=head1 NAME
C<perl5db.pl> - the perl debugger
=head1 SYNOPSIS
perl -d your_Perl_script
=head1 DESCRIPTION
C<perl5db.pl> is the perl debugger. It is loaded automatically by Perl when
you invoke a script with C<perl -d>. This documentation tries to outline the
structure and services provided by C<perl5db.pl>, and to describe how you
can use them.
=head1 GENERAL NOTES
The debugger can look pretty forbidding to many Perl programmers. There are
a number of reasons for this, many stemming out of the debugger's history.
When the debugger was first written, Perl didn't have a lot of its nicer
features - no references, no lexical variables, no closures, no object-oriented
programming. So a lot of the things one would normally have done using such
features was done using global variables, globs and the C<local()> operator
in creative ways.
Some of these have survived into the current debugger; a few of the more
interesting and still-useful idioms are noted in this section, along with notes
on the comments themselves.
=head2 Why not use more lexicals?
Experienced Perl programmers will note that the debugger code tends to use
mostly package globals rather than lexically-scoped variables. This is done
to allow a significant amount of control of the debugger from outside the
debugger itself.
Unfortunately, though the variables are accessible, they're not well
documented, so it's generally been a decision that hasn't made a lot of
difference to most users. Where appropriate, comments have been added to
make variables more accessible and usable, with the understanding that these
i<are> debugger internals, and are therefore subject to change. Future
development should probably attempt to replace the globals with a well-defined
API, but for now, the variables are what we've got.
=head2 Automated variable stacking via C<local()>
As you may recall from reading C<perlfunc>, the C<local()> operator makes a
temporary copy of a variable in the current scope. When the scope ends, the
old copy is restored. This is often used in the debugger to handle the
automatic stacking of variables during recursive calls:
sub foo {
local $some_global++;
# Do some stuff, then ...
return;
}
What happens is that on entry to the subroutine, C<$some_global> is localized,
then altered. When the subroutine returns, Perl automatically undoes the
localization, restoring the previous value. Voila, automatic stack management.
The debugger uses this trick a I<lot>. Of particular note is C<DB::eval>,
which lets the debugger get control inside of C<eval>'ed code. The debugger
localizes a saved copy of C<$@> inside the subroutine, which allows it to
keep C<$@> safe until it C<DB::eval> returns, at which point the previous
value of C<$@> is restored. This makes it simple (well, I<simpler>) to keep
track of C<$@> inside C<eval>s which C<eval> other C<eval's>.
In any case, watch for this pattern. It occurs fairly often.
=head2 The C<^> trick
This is used to cleverly reverse the sense of a logical test depending on
the value of an auxiliary variable. For instance, the debugger's C<S>
(search for subroutines by pattern) allows you to negate the pattern
like this:
# Find all non-'foo' subs:
S !/foo/
Boolean algebra states that the truth table for XOR looks like this:
=over 4
=item * 0 ^ 0 = 0
(! not present and no match) --> false, don't print
=item * 0 ^ 1 = 1
(! not present and matches) --> true, print
=item * 1 ^ 0 = 1
(! present and no match) --> true, print
=item * 1 ^ 1 = 0
(! present and matches) --> false, don't print
=back
As you can see, the first pair applies when C<!> isn't supplied, and
the second pair applies when it isn't. The XOR simply allows us to
compact a more complicated if-then-elseif-else into a more elegant
(but perhaps overly clever) single test. After all, it needed this
explanation...
=head2 FLAGS, FLAGS, FLAGS
There is a certain C programming legacy in the debugger. Some variables,
such as C<$single>, C<$trace>, and C<$frame>, have "magical" values composed
of 1, 2, 4, etc. (powers of 2) OR'ed together. This allows several pieces
of state to be stored independently in a single scalar.
A test like
if ($scalar & 4) ...
is checking to see if the appropriate bit is on. Since each bit can be
"addressed" independently in this way, C<$scalar> is acting sort of like
an array of bits. Obviously, since the contents of C<$scalar> are just a
bit-pattern, we can save and restore it easily (it will just look like
a number).
The problem, is of course, that this tends to leave magic numbers scattered
all over your program whenever a bit is set, cleared, or checked. So why do
it?
=over 4
=item * First, doing an arithmetical or bitwise operation on a scalar is
just about the fastest thing you can do in Perl: C<use constant> actually
creates a subroutine call, and array hand hash lookups are much slower. Is
this over-optimization at the expense of readability? Possibly, but the
debugger accesses these variables a I<lot>. Any rewrite of the code will
probably have to benchmark alternate implementations and see which is the
best balance of readability and speed, and then document how it actually
works.
=item * Second, it's very easy to serialize a scalar number. This is done in
the restart code; the debugger state variables are saved in C<%ENV> and then
restored when the debugger is restarted. Having them be just numbers makes
this trivial.
=item * Third, some of these variables are being shared with the Perl core
smack in the middle of the interpreter's execution loop. It's much faster for
a C program (like the interpreter) to check a bit in a scalar than to access
several different variables (or a Perl array).
=back
=head2 What are those C<XXX> comments for?
Any comment containing C<XXX> means that the comment is either somewhat
speculative - it's not exactly clear what a given variable or chunk of
code is doing, or that it is incomplete - the basics may be clear, but the
subtleties are not completely documented.
Send in a patch if you can clear up, fill out, or clarify an C<XXX>.
=head1 DATA STRUCTURES MAINTAINED BY CORE
There are a number of special data structures provided to the debugger by
the Perl interpreter.
The array C<@{$main::{'_<'.$filename}}> (aliased locally to C<@dbline> via glob
assignment) contains the text from C<$filename>, with each element
corresponding to a single line of C<$filename>.
The hash C<%{'_<'.$filename}> (aliased locally to C<%dbline> via glob
assignment) contains breakpoints and actions. The keys are line numbers;
you can set individual values, but not the whole hash. The Perl interpreter
uses this hash to determine where breakpoints have been set. Any true value is
considered to be a breakpoint; C<perl5db.pl> uses "$break_condition\0$action".
Values are magical in numeric context: 1 if the line is breakable, 0 if not.
The scalar ${'_<'.$filename} contains $filename XXX What?
=head1 DEBUGGER STARTUP
When C<perl5db.pl> starts, it reads an rcfile (C<perl5db.ini> for
non-interactive sessions, C<.perldb> for interactive ones) that can set a number
of options. In addition, this file may define a subroutine C<&afterinit>
that will be executed (in the debugger's context) after the debugger has
initialized itself.
Next, it checks the C<PERLDB_OPTS> environment variable and treats its
contents as the argument of a debugger <C<o> command.
=head2 STARTUP-ONLY OPTIONS
The following options can only be specified at startup.
To set them in your rcfile, add a call to
C<&parse_options("optionName=new_value")>.
=over 4
=item * TTY
the TTY to use for debugging i/o.
=item * noTTY
if set, goes in NonStop mode. On interrupt, if TTY is not set,
Term::Rendezvous. Current variant is to have the name of TTY in this
file.
=item * ReadLine
If false, a dummy ReadLine is used, so you can debug
ReadLine applications.
=item * NonStop
if true, no i/o is performed until interrupt.
=item * LineInfo
file or pipe to print line number info to. If it is a
pipe, a short "emacs like" message is used.
=item * RemotePort
host:port to connect to on remote host for remote debugging.
=back
=head3 SAMPLE RCFILE
&parse_options("NonStop=1 LineInfo=db.out");
sub afterinit { $trace = 1; }
The script will run without human intervention, putting trace
information into C<db.out>. (If you interrupt it, you had better
reset C<LineInfo> to something "interactive"!)
=head1 INTERNALS DESCRIPTION
=head2 DEBUGGER INTERFACE VARIABLES
Perl supplies the values for C<%sub>. It effectively inserts
a C<&DB'DB();> in front of each place that can have a
breakpoint. At each subroutine call, it calls C<&DB::sub> with
C<$DB::sub> set to the called subroutine. It also inserts a C<BEGIN
{require 'perl5db.pl'}> before the first line.
After each C<require>d file is compiled, but before it is executed, a
call to C<&DB::postponed($main::{'_<'.$filename})> is done. C<$filename>
is the expanded name of the C<require>d file (as found via C<%INC>).
=head3 IMPORTANT INTERNAL VARIABLES
=head4 C<$CreateTTY>
Used to control when the debugger will attempt to acquire another TTY to be
used for input.
=over
=item * 1 - on C<fork()>
=item * 2 - debugger is started inside debugger
=item * 4 - on startup
=back
=head4 C<$doret>
The value -2 indicates that no return value should be printed.
Any other positive value causes C<DB::sub> to print return values.
=head4 C<$evalarg>
The item to be eval'ed by C<DB::eval>. Used to prevent messing with the current
contents of C<@_> when C<DB::eval> is called.
=head4 C<$frame>
Determines what messages (if any) will get printed when a subroutine (or eval)
is entered or exited.
=over 4
=item * 1 - Print "entering" messages on subroutine entry
=item * 2 - Adds exit messages on subroutine exit. If no other flag is on, acts like 1+2.
=item * 4 - Extended messages: C<in|out> I<context>=I<fully-qualified sub name> from I<file>:I<line>>. If no other flag is on, acts like 1+4.
=item * 8 - Adds parameter information to messages, and overloaded stringify and tied FETCH is enabled on the printed arguments. Ignored if C<4> is not on.
=item * 16 - Adds C<I<context> return from I<subname>: I<value>> messages on subroutine/eval exit. Ignored if C<4> is is not on.
=back
To get everything, use C<$frame=30> (or C<o f-30> as a debugger command).
The debugger internally juggles the value of C<$frame> during execution to
protect external modules that the debugger uses from getting traced.
=head4 C<$level>
Tracks current debugger nesting level. Used to figure out how many
C<E<lt>E<gt>> pairs to surround the line number with when the debugger
outputs a prompt. Also used to help determine if the program has finished
during command parsing.
=head4 C<$onetimeDump>
Controls what (if anything) C<DB::eval()> will print after evaluating an
expression.
=over 4
=item * C<undef> - don't print anything
=item * C<dump> - use C<dumpvar.pl> to display the value returned
=item * C<methods> - print the methods callable on the first item returned
=back
=head4 C<$onetimeDumpDepth>
Controls how far down C<dumpvar.pl> will go before printing '...' while
dumping a structure. Numeric. If C<undef>, print all levels.
=head4 C<$signal>
Used to track whether or not an C<INT> signal has been detected. C<DB::DB()>,
which is called before every statement, checks this and puts the user into
command mode if it finds C<$signal> set to a true value.
=head4 C<$single>
Controls behavior during single-stepping. Stacked in C<@stack> on entry to
each subroutine; popped again at the end of each subroutine.
=over 4
=item * 0 - run continuously.
=item * 1 - single-step, go into subs. The 's' command.
=item * 2 - single-step, don't go into subs. The 'n' command.
=item * 4 - print current sub depth (turned on to force this when "too much
recursion" occurs.
=back
=head4 C<$trace>
Controls the output of trace information.
=over 4
=item * 1 - The C<t> command was entered to turn on tracing (every line executed is printed)
=item * 2 - watch expressions are active
=item * 4 - user defined a C<watchfunction()> in C<afterinit()>
=back
=head4 C<$slave_editor>
1 if C<LINEINFO> was directed to a pipe; 0 otherwise.
=head4 C<@cmdfhs>
Stack of filehandles that C<DB::readline()> will read commands from.
Manipulated by the debugger's C<source> command and C<DB::readline()> itself.
=head4 C<@dbline>
Local alias to the magical line array, C<@{$main::{'_<'.$filename}}> ,
supplied by the Perl interpreter to the debugger. Contains the source.
=head4 C<@old_watch>
Previous values of watch expressions. First set when the expression is
entered; reset whenever the watch expression changes.
=head4 C<@saved>
Saves important globals (C<$@>, C<$!>, C<$^E>, C<$,>, C<$/>, C<$\>, C<$^W>)
so that the debugger can substitute safe values while it's running, and
restore them when it returns control.
=head4 C<@stack>
Saves the current value of C<$single> on entry to a subroutine.
Manipulated by the C<c> command to turn off tracing in all subs above the
current one.
=head4 C<@to_watch>
The 'watch' expressions: to be evaluated before each line is executed.
=head4 C<@typeahead>
The typeahead buffer, used by C<DB::readline>.
=head4 C<%alias>
Command aliases. Stored as character strings to be substituted for a command
entered.
=head4 C<%break_on_load>
Keys are file names, values are 1 (break when this file is loaded) or undef
(don't break when it is loaded).
=head4 C<%dbline>
Keys are line numbers, values are "condition\0action". If used in numeric
context, values are 0 if not breakable, 1 if breakable, no matter what is
in the actual hash entry.
=head4 C<%had_breakpoints>
Keys are file names; values are bitfields:
=over 4
=item * 1 - file has a breakpoint in it.
=item * 2 - file has an action in it.
=back
A zero or undefined value means this file has neither.
=head4 C<%option>
Stores the debugger options. These are character string values.
=head4 C<%postponed>
Saves breakpoints for code that hasn't been compiled yet.
Keys are subroutine names, values are:
=over 4
=item * 'compile' - break when this sub is compiled
=item * 'break +0 if <condition>' - break (conditionally) at the start of this routine. The condition will be '1' if no condition was specified.
=back
=head4 C<%postponed_file>
This hash keeps track of breakpoints that need to be set for files that have
not yet been compiled. Keys are filenames; values are references to hashes.
Each of these hashes is keyed by line number, and its values are breakpoint
definitions ("condition\0action").
=head1 DEBUGGER INITIALIZATION
The debugger's initialization actually jumps all over the place inside this
package. This is because there are several BEGIN blocks (which of course
execute immediately) spread through the code. Why is that?
The debugger needs to be able to change some things and set some things up
before the debugger code is compiled; most notably, the C<$deep> variable that
C<DB::sub> uses to tell when a program has recursed deeply. In addition, the
debugger has to turn off warnings while the debugger code is compiled, but then
restore them to their original setting before the program being debugged begins
executing.
The first C<BEGIN> block simply turns off warnings by saving the current
setting of C<$^W> and then setting it to zero. The second one initializes
the debugger variables that are needed before the debugger begins executing.
The third one puts C<$^X> back to its former value.
We'll detail the second C<BEGIN> block later; just remember that if you need
to initialize something before the debugger starts really executing, that's
where it has to go.
=cut
package DB;
# Debugger for Perl 5.00x; perl5db.pl patch level:
$VERSION = 1.25;
$header = "perl5db.pl version $VERSION";
=head1 DEBUGGER ROUTINES
=head2 C<DB::eval()>
This function replaces straight C<eval()> inside the debugger; it simplifies
the process of evaluating code in the user's context.
The code to be evaluated is passed via the package global variable
C<$DB::evalarg>; this is done to avoid fiddling with the contents of C<@_>.
We preserve the current settings of X<C<$trace>>, X<C<$single>>, and X<C<$^D>>;
add the X<C<$usercontext>> (that's the preserved values of C<$@>, C<$!>,
C<$^E>, C<$,>, C<$/>, C<$\>, and C<$^W>, grabbed when C<DB::DB> got control,
and the user's current package) and a add a newline before we do the C<eval()>.
This causes the proper context to be used when the eval is actually done.
Afterward, we restore C<$trace>, C<$single>, and C<$^D>.
Next we need to handle C<$@> without getting confused. We save C<$@> in a
local lexical, localize C<$saved[0]> (which is where C<save()> will put
C<$@>), and then call C<save()> to capture C<$@>, C<$!>, C<$^E>, C<$,>,
C<$/>, C<$\>, and C<$^W>) and set C<$,>, C<$/>, C<$\>, and C<$^W> to values
considered sane by the debugger. If there was an C<eval()> error, we print
it on the debugger's output. If X<C<$onetimedump>> is defined, we call
X<C<dumpit>> if it's set to 'dump', or X<C<methods>> if it's set to
'methods'. Setting it to something else causes the debugger to do the eval
but not print the result - handy if you want to do something else with it
(the "watch expressions" code does this to get the value of the watch
expression but not show it unless it matters).
In any case, we then return the list of output from C<eval> to the caller,
and unwinding restores the former version of C<$@> in C<@saved> as well
(the localization of C<$saved[0]> goes away at the end of this scope).
=head3 Parameters and variables influencing execution of DB::eval()
C<DB::eval> isn't parameterized in the standard way; this is to keep the
debugger's calls to C<DB::eval()> from mucking with C<@_>, among other things.
The variables listed below influence C<DB::eval()>'s execution directly.
=over 4
=item C<$evalarg> - the thing to actually be eval'ed
=item C<$trace> - Current state of execution tracing (see X<$trace>)
=item C<$single> - Current state of single-stepping (see X<$single>)
=item C<$onetimeDump> - what is to be displayed after the evaluation
=item C<$onetimeDumpDepth> - how deep C<dumpit()> should go when dumping results
=back
The following variables are altered by C<DB::eval()> during its execution. They
are "stacked" via C<local()>, enabling recursive calls to C<DB::eval()>.
=over 4
=item C<@res> - used to capture output from actual C<eval>.
=item C<$otrace> - saved value of C<$trace>.
=item C<$osingle> - saved value of C<$single>.
=item C<$od> - saved value of C<$^D>.
=item C<$saved[0]> - saved value of C<$@>.
=item $\ - for output of C<$@> if there is an evaluation error.
=back
=head3 The problem of lexicals
The context of C<DB::eval()> presents us with some problems. Obviously,
we want to be 'sandboxed' away from the debugger's internals when we do
the eval, but we need some way to control how punctuation variables and
debugger globals are used.
We can't use local, because the code inside C<DB::eval> can see localized
variables; and we can't use C<my> either for the same reason. The code
in this routine compromises and uses C<my>.
After this routine is over, we don't have user code executing in the debugger's
context, so we can use C<my> freely.
=cut
############################################## Begin lexical danger zone
# 'my' variables used here could leak into (that is, be visible in)
# the context that the code being evaluated is executing in. This means that
# the code could modify the debugger's variables.
#
# Fiddling with the debugger's context could be Bad. We insulate things as
# much as we can.
sub eval {
# 'my' would make it visible from user code
# but so does local! --tchrist
# Remember: this localizes @DB::res, not @main::res.
local @res;
{
# Try to keep the user code from messing with us. Save these so that
# even if the eval'ed code changes them, we can put them back again.
# Needed because the user could refer directly to the debugger's
# package globals (and any 'my' variables in this containing scope)
# inside the eval(), and we want to try to stay safe.
local $od = $^D;
# Untaint the incoming eval() argument.
# $usercontext built in DB::DB near the comment
# "set up the context for DB::eval ..."
# Evaluate and save any results.
@res =
eval "$usercontext $evalarg;\n"; # '\n' for nice recursive debug
# Restore those old values.
$^D = $od;
}
# Save the current value of $@, and preserve it in the debugger's copy
# of the saved precious globals.
my $at = $@;
# Since we're only saving $@, we only have to localize the array element
# that it will be stored in.
# Now see whether we need to report an error back to the user.
if ($at) {
local $\ = '';
}
# Display as required by the caller. $onetimeDump and $onetimedumpDepth
# are package globals.
elsif ($onetimeDump) {
if ($onetimeDump eq 'dump') {
if defined $onetimedumpDepth;
}
elsif ($onetimeDump eq 'methods') {
}
} ## end elsif ($onetimeDump)
@res;
} ## end sub eval
############################################## End lexical danger zone
# After this point it is safe to introduce lexicals.
# The code being debugged will be executing in its own context, and
# can't see the inside of the debugger.
#
# However, one should not overdo it: leave as much control from outside as
# possible. If you make something a lexical, it's not going to be addressable
# from outside the debugger even if you know its name.
# This file is automatically included if you do perl -d.
# It's probably not useful to include this yourself.
#
# Before venturing further into these twisty passages, it is
# wise to read the perldebguts man page or risk the ire of dragons.
#
# (It should be noted that perldebguts will tell you a lot about
# the underlying mechanics of how the debugger interfaces into the
# Perl interpreter, but not a lot about the debugger itself. The new
# comments in this code try to address this problem.)
# Note that no subroutine call is possible until &DB::sub is defined
# (for subroutines defined outside of the package DB). In fact the same is
# true if $deep is not defined.
#
# $Log: perldb.pl,v $
# Enhanced by ilya@math.ohio-state.edu (Ilya Zakharevich)
# modified Perl debugger, to be run from Emacs in perldb-mode
# Ray Lischner (uunet!mntgfx!lisch) as of 5 Nov 1990
# Johan Vromans -- upgrade to 4.0 pl 10
# Ilya Zakharevich -- patches after 5.001 (and some before ;-)
# (We have made efforts to clarify the comments in the change log
# in other places; some of them may seem somewhat obscure as they
# were originally written, and explaining them away from the code
# in question seems conterproductive.. -JM)
########################################################################
# Changes: 0.94
# + A lot of things changed after 0.94. First of all, core now informs
# debugger about entry into XSUBs, overloaded operators, tied operations,
# BEGIN and END. Handy with `O f=2'.
# + This can make debugger a little bit too verbose, please be patient
# and report your problems promptly.
# + Now the option frame has 3 values: 0,1,2. XXX Document!
# + Note that if DESTROY returns a reference to the object (or object),
# the deletion of data may be postponed until the next function call,
# due to the need to examine the return value.
#
# Changes: 0.95
# + `v' command shows versions.
#
# Changes: 0.96
# + `v' command shows version of readline.
# primitive completion works (dynamic variables, subs for `b' and `l',
# options). Can `p %var'
# + Better help (`h <' now works). New commands <<, >>, {, {{.
# {dump|print}_trace() coded (to be able to do it from <<cmd).
# + `c sub' documented.
# + At last enough magic combined to stop after the end of debuggee.
# + !! should work now (thanks to Emacs bracket matching an extra
# `]' in a regexp is caught).
# + `L', `D' and `A' span files now (as documented).
# + Breakpoints in `require'd code are possible (used in `R').
# + Some additional words on internal work of debugger.
# + `b load filename' implemented.
# + `b postpone subr' implemented.
# + now only `q' exits debugger (overwritable on $inhibit_exit).
# + When restarting debugger breakpoints/actions persist.
# + Buglet: When restarting debugger only one breakpoint/action per
# autoloaded function persists.
#
# Changes: 0.97: NonStop will not stop in at_exit().
# + Option AutoTrace implemented.
# + Trace printed differently if frames are printed too.
# + new `inhibitExit' option.
# + printing of a very long statement interruptible.
# Changes: 0.98: New command `m' for printing possible methods
# + 'l -' is a synonym for `-'.
# + Cosmetic bugs in printing stack trace.
# + `frame' & 8 to print "expanded args" in stack trace.
# + new `maxTraceLen' option.
# + frame & 4 and frame & 8 granted.
# + new command `m'
# + nonstoppable lines do not have `:' near the line number.
# + `b compile subname' implemented.
# + Will not use $` any more.
# + `-' behaves sane now.
# Changes: 0.99: Completion for `f', `m'.
# + `m' will remove duplicate names instead of duplicate functions.
# + `b load' strips trailing whitespace.
# completion ignores leading `|'; takes into account current package
# when completing a subroutine name (same for `l').
# Changes: 1.07: Many fixed by tchrist 13-March-2000
# BUG FIXES:
# + Added bare minimal security checks on perldb rc files, plus
# comments on what else is needed.
# + Fixed the ornaments that made "|h" completely unusable.
# They are not used in print_help if they will hurt. Strip pod
# if we're paging to less.
# + Fixed mis-formatting of help messages caused by ornaments
# to restore Larry's original formatting.
# + Fixed many other formatting errors. The code is still suboptimal,
# and needs a lot of work at restructuring. It's also misindented
# in many places.
# + Fixed bug where trying to look at an option like your pager
# shows "1".
# + Fixed some $? processing. Note: if you use csh or tcsh, you will
# lose. You should consider shell escapes not using their shell,
# or else not caring about detailed status. This should really be
# unified into one place, too.
# + Fixed bug where invisible trailing whitespace on commands hoses you,
# tricking Perl into thinking you weren't calling a debugger command!
# + Fixed bug where leading whitespace on commands hoses you. (One
# suggests a leading semicolon or any other irrelevant non-whitespace
# to indicate literal Perl code.)
# + Fixed bugs that ate warnings due to wrong selected handle.
# + Fixed a precedence bug on signal stuff.
# + Fixed some unseemly wording.
# + Fixed bug in help command trying to call perl method code.
# + Fixed to call dumpvar from exception handler. SIGPIPE killed us.
# ENHANCEMENTS:
# + Added some comments. This code is still nasty spaghetti.
# very easy to do if you just typed a bare >, <, or {. (A command
# without an argument should *never* be a destructive action; this
# API is fundamentally screwed up; likewise option setting, which
# is equally buggered.)
# + Added command stack dump on argument of "?" for >, <, or {.
# + Added a semi-built-in doc viewer command that calls man with the
# proper %Config::Config path (and thus gets caching, man -k, etc),
# or else perldoc on obstreperous platforms.
# + Added to and rearranged the help information.
# + Detected apparent misuse of { ... } to declare a block; this used
# to work but now is a command, and mysteriously gave no complaint.
#
# Changes: 1.08: Apr 25, 2001 Jon Eveland <jweveland@yahoo.com>
# BUG FIX:
# + This patch to perl5db.pl cleans up formatting issues on the help
# summary (h h) screen in the debugger. Mostly columnar alignment
# issues, plus converted the printed text to use all spaces, since
# tabs don't seem to help much here.
#
# Changes: 1.09: May 19, 2001 Ilya Zakharevich <ilya@math.ohio-state.edu>
# Minor bugs corrected;
# + Support for auto-creation of new TTY window on startup, either
# unconditionally, or if started as a kid of another debugger session;
# + New `O'ption CreateTTY
# I<CreateTTY> bits control attempts to create a new TTY on events:
# 1: on fork()
# 2: debugger is started inside debugger
# 4: on startup
# + Code to auto-create a new TTY window on OS/2 (currently one
# extra window per session - need named pipes to have more...);
# + Simplified interface for custom createTTY functions (with a backward
# compatibility hack); now returns the TTY name to use; return of ''
# means that the function reset the I/O handles itself;
# + Better message on the semantic of custom createTTY function;
# + Convert the existing code to create a TTY into a custom createTTY
# function;
# + Consistent support for TTY names of the form "TTYin,TTYout";
# + Switch line-tracing output too to the created TTY window;
# + make `b fork' DWIM with CORE::GLOBAL::fork;
# + High-level debugger API cmd_*():
# cmd_b_load($filenamepart) # b load filenamepart
# cmd_b_line($lineno [, $cond]) # b lineno [cond]
# cmd_b_sub($sub [, $cond]) # b sub [cond]
# cmd_stop() # Control-C
# cmd_d($lineno) # d lineno (B)
# The cmd_*() API returns FALSE on failure; in this case it outputs
# the error message to the debugging output.
# + Low-level debugger API
# break_on_load($filename) # b load filename
# @files = report_break_on_load() # List files with load-breakpoints
# breakable_line_in_filename($name, $from [, $to])
# # First breakable line in the
# # range $from .. $to. $to defaults
# # to $from, and may be less than
# # $to
# breakable_line($from [, $to]) # Same for the current file
# break_on_filename_line($name, $lineno [, $cond])
# # Set breakpoint,$cond defaults to
# # 1
# break_on_filename_line_range($name, $from, $to [, $cond])
# # As above, on the first
# # breakable line in range
# break_on_line($lineno [, $cond]) # As above, in the current file
# break_subroutine($sub [, $cond]) # break on the first breakable line
# ($name, $from, $to) = subroutine_filename_lines($sub)
# # The range of lines of the text
# The low-level API returns TRUE on success, and die()s on failure.
#
# Changes: 1.10: May 23, 2001 Daniel Lewart <d-lewart@uiuc.edu>
# BUG FIXES:
# + Fixed warnings generated by "perl -dWe 42"
# + Corrected spelling errors
# + Squeezed Help (h) output into 80 columns
#
# Changes: 1.11: May 24, 2001 David Dyck <dcd@tc.fluke.com>
# + Made "x @INC" work like it used to
#
# Changes: 1.12: May 24, 2001 Daniel Lewart <d-lewart@uiuc.edu>
# + Fixed warnings generated by "O" (Show debugger options)
# + Fixed warnings generated by "p 42" (Print expression)
# Changes: 1.13: Jun 19, 2001 Scott.L.Miller@compaq.com
# + Added windowSize option
# Changes: 1.14: Oct 9, 2001 multiple
# + Clean up after itself on VMS (Charles Lane in 12385)
# + Adding "@ file" syntax (Peter Scott in 12014)
# + Debug reloading selfloaded stuff (Ilya Zakharevich in 11457)
# + $^S and other debugger fixes (Ilya Zakharevich in 11120)
# + Forgot a my() declaration (Ilya Zakharevich in 11085)
# Changes: 1.15: Nov 6, 2001 Michael G Schwern <schwern@pobox.com>
# + Updated 1.14 change log
# + Added *dbline explainatory comments
# + Mentioning perldebguts man page
# Changes: 1.16: Feb 15, 2002 Mark-Jason Dominus <mjd@plover.com>
# + $onetimeDump improvements
# Changes: 1.17: Feb 20, 2002 Richard Foley <richard.foley@rfi.net>
# Moved some code to cmd_[.]()'s for clarity and ease of handling,
# rationalised the following commands and added cmd_wrapper() to
# enable switching between old and frighteningly consistent new
# behaviours for diehards: 'o CommandSet=pre580' (sigh...)
# a(add), A(del) # action expr (added del by line)
# + b(add), B(del) # break [line] (was b,D)
# + w(add), W(del) # watch expr (was W,W)
# # added del by expr
# + h(summary), h h(long) # help (hh) (was h h,h)
# + m(methods), M(modules) # ... (was m,v)
# + o(option) # lc (was O)
# + v(view code), V(view Variables) # ... (was w,V)
# Changes: 1.18: Mar 17, 2002 Richard Foley <richard.foley@rfi.net>
# + fixed missing cmd_O bug
# Changes: 1.19: Mar 29, 2002 Spider Boardman
# + Added missing local()s -- DB::DB is called recursively.
# Changes: 1.20: Feb 17, 2003 Richard Foley <richard.foley@rfi.net>
# + pre'n'post commands no longer trashed with no args
# + watch val joined out of eval()
# Changes: 1.21: Jun 04, 2003 Joe McMahon <mcmahon@ibiblio.org>
# + Added comments and reformatted source. No bug fixes/enhancements.
# + Includes cleanup by Robin Barker and Jarkko Hietaniemi.
# Changes: 1.22 Jun 09, 2003 Alex Vandiver <alexmv@MIT.EDU>
# Changes: 1.23: Dec 21, 2003 Dominique Quatravaux
# + Fix a side-effect of bug #24674 in the perl debugger ("odd taint bug")
# Changes: 1.24: Mar 03, 2004 Richard Foley <richard.foley@rfi.net>
# + Added command to save all debugger commands for sourcing later.
# + Added command to display parent inheritence tree of given class.
# + Fixed minor newline in history bug.
# Changes: 1.25: Apr 17, 2004 Richard Foley <richard.foley@rfi.net>
# + Fixed option bug (setting invalid options + not recognising valid short forms)
####################################################################
=head1 DEBUGGER INITIALIZATION
The debugger starts up in phases.
=head2 BASIC SETUP
First, it initializes the environment it wants to run in: turning off
warnings during its own compilation, defining variables which it will need
to avoid warnings later, setting itself up to not exit when the program
terminates, and defaulting to printing return values for the C<r> command.
=cut
# Needed for the statement after exec():
#
# This BEGIN block is simply used to switch off warnings during debugger
# compiliation. Probably it would be better practice to fix the warnings,
# but this is how it's done at the moment.
BEGIN {
$ini_warn = $^W;
$^W = 0;
} # Switch compilation warnings off until another BEGIN.
local ($^W) = 0; # Switch run-time warnings off during init.
# This would probably be better done with "use vars", but that wasn't around
# when this code was originally written. (Neither was "use strict".) And on
# the principle of not fiddling with something that was working, this was
# left alone.
warn( # Do not ;-)
# These variables control the execution of 'dumpvar.pl'.
# used to save @ARGV and extract any debugger-related flags.
@ARGS,
# used to control die() reporting in diesignal()
# used to prevent multiple entries to diesignal()
# (if for instance diesignal() itself dies)
$panic,
# used to prevent the debugger from running nonstop
# after a restart
)
if 0;
# Command-line + PERLLIB:
# Save the contents of @INC before they are modified elsewhere.
# This was an attempt to clear out the previous values of various
# trapped errors. Apparently it didn't help. XXX More info needed!
# $prevwarn = $prevdie = $prevbus = $prevsegv = ''; # Does not help?!
# We set these variables to safe values. We don't want to blindly turn
# off warnings, because other packages may still want them.
# (local $^W cannot help - other packages!).
# Default to not exiting when program finishes; print the return
# value when the 'r' command is used to return from a subroutine.
=head1 OPTION PROCESSING
The debugger's options are actually spread out over the debugger itself and
C<dumpvar.pl>; some of these are variables to be set, while others are
subs to be called with a value. To try to make this a little easier to
manage, the debugger uses a few data structures to define what options
are legal and how they are to be processed.
First, the C<@options> array defines the I<names> of all the options that
are to be accepted.
=cut
@options = qw(
);
=pod
Second, C<optionVars> lists the variables that each option uses to save its
state.
=cut
%optionVars = (
CommandSet => \$CommandSet,
inhibit_exit => \$inhibit_exit,
maxTraceLen => \$maxtrace,
ImmediateStop => \$ImmediateStop,
RemotePort => \$remoteport,
windowSize => \$window,
);
=pod
Third, C<%optionAction> defines the subroutine to be called to process each
option.
=cut
%optionAction = (
recallCommand => \&recallCommand,
signalLevel => \&signalLevel,
RemotePort => \&RemotePort,
);
=pod
Last, the C<%optionRequire> notes modules that must be C<require>d if an
option is used.
=cut
# Note that this list is not complete: several options not listed here
# actually require that dumpvar.pl be loaded for them to work, but are
# not in the table. A subsequent patch will correct this problem; for
# the moment, we're just recommenting, and we are NOT going to change
# function.
%optionRequire = (
compactDump => 'dumpvar.pl',
veryCompact => 'dumpvar.pl',
quote => 'dumpvar.pl',
);
=pod
There are a number of initialization-related variables which can be set
by putting code to set them in a BEGIN block in the C<PERL5DB> environment
variable. These are:
=over 4
=item C<$rl> - readline control XXX needs more explanation
=item C<$warnLevel> - whether or not debugger takes over warning handling
=item C<$dieLevel> - whether or not debugger takes over die handling
=item C<$signalLevel> - whether or not debugger takes over signal handling
=item C<$pre> - preprompt actions (array reference)
=item C<$post> - postprompt actions (array reference)
=item C<$pretype>
=item C<$CreateTTY> - whether or not to create a new TTY for this debugger
=item C<$CommandSet> - which command set to use (defaults to new, documented set)
=back
=cut
# These guys may be defined in $ENV{PERL5DB} :
=pod
The default C<die>, C<warn>, and C<signal> handlers are set up.
=cut
=pod
The pager to be used is needed next. We try to get it from the
environment first. if it's not defined there, we try to find it in
the Perl C<Config.pm>. If it's not there, we default to C<more>. We
then call the C<pager()> function to save the pager name.
=cut
# This routine makes sure $pager is set up so that '|' can use it.
# If PAGER is defined in the environment, use it.
# If not, see if Config.pm defines it.
# If not, fall back to 'more'.
: 'more'
)
unless defined $pager;
=pod
We set up the command to be used to access the man pages, the command
recall character ("!" unless otherwise defined) and the shell escape
character ("!" unless otherwise defined). Yes, these do conflict, and
neither works in the debugger at the moment.
=cut
setman();
# Set up defaults for command recall and shell escape (note:
# these currently don't work in linemode debugging).
=pod
We then set up the gigantic string containing the debugger help.
We also set the limit on the number of arguments we'll display during a
trace.
=cut
sethelp();
# set it here.
=head2 SETTING UP THE DEBUGGER GREETING
The debugger 'greeting' helps to inform the user how many debuggers are
running, and whether the current debugger is the primary or a child.
If we are the primary, we just hang onto our pid so we'll have it when
or if we start a child debugger. If we are a child, we'll set things up
so we'll have a unique greeting and so the parent will give us our own
TTY later.
We save the current contents of the C<PERLDB_PIDS> environment variable
because we mess around with it. We'll also need to hang onto it because
we'll need it if we restart.
Child debuggers make a label out of the current PID structure recorded in
PERLDB_PIDS plus the new PID. They also mark themselves as not having a TTY
yet so the parent will give them one later via C<resetterm()>.
=cut
# Save the current contents of the environment; we're about to
# much with it. We'll need this if we have to restart.
if (defined $ENV{PERLDB_PIDS}) {
# We're a child. Make us a label out of the current PID structure
# recorded in PERLDB_PIDS plus our (new) PID. Mark us as not having
# a term yet so the parent will give us one later via resetterm().
$pids = "[$ENV{PERLDB_PIDS}]";
$term_pid = -1;
} ## end if (defined $ENV{PERLDB_PIDS...
else {
# We're the parent PID. Initialize PERLDB_PID in case we end up with a
# child debugger, and mark us as the parent, so we'll know to set up
# more TTY's is we have to.
$pids = "{pid=$$}";
$term_pid = $$;
}
$pidprompt = '';
# Sets up $emacs as a synonym for $slave_editor.
=head2 READING THE RC FILE
The debugger will read a file of initialization options if supplied. If
running interactively, this is C<.perldb>; if not, it's C<perldb.ini>.
=cut
# As noted, this test really doesn't check accurately that the debugger
# is running at a terminal or not.
$rcfile = ".perldb";
}
else {
$rcfile = "perldb.ini";
}
=pod
The debugger does a safety test of the file to be read. It must be owned
either by the current user or root, and must only be writable by the owner.
=cut
# This wraps a safety test around "do" to read and evaluate the init file.
#
# This isn't really safe, because there's a race
# between checking and opening. The solution is to
# open and fstat the handle, but then you have to read and
# eval the contents. But then the silly thing gets
# your lexical scope, which is unfortunate at best.
sub safe_do {
my $file = shift;
# Just exactly what part of the word "CORE::" don't you understand?
unless (is_safe_file($file)) {
return;
} ## end unless (is_safe_file($file...
do $file;
CORE::warn("perldb: couldn't parse $file: $@") if $@;
} ## end sub safe_do
# This is the safety test itself.
#
# Verifies that owner is either real user or superuser and that no
# one but owner may write to it. This function is of limited use
# when called on a path instead of upon a handle, because there are
# no guarantees that filename (by dirent) whose file (by ino) is
# eventually accessed is the same as the one tested.
# Assumes that the file's existence is not in doubt.
sub is_safe_file {
my $path = shift;
stat($path) || return; # mysteriously vaporized
return 1;
} ## end sub is_safe_file
# If the rcfile (whichever one we decided was the right one to read)
# exists, we safely do it.
if (-f $rcfile) {
safe_do("./$rcfile");
}
# If there isn't one here, try the user's home directory.
safe_do("$ENV{HOME}/$rcfile");
}
# Else try the login directory.
safe_do("$ENV{LOGDIR}/$rcfile");
}
# If the PERLDB_OPTS variable has options in it, parse those out next.
if (defined $ENV{PERLDB_OPTS}) {
}
=pod
The last thing we do during initialization is determine which subroutine is
to be used to obtain a new terminal when a new debugger is started. Right now,
the debugger only handles X Windows and OS/2.
=cut
# Set up the get_fork_TTY subroutine to be aliased to the proper routine.
# Works if you're running an xterm or xterm-like window, or you're on
# OS/2. This may need some expansion: for instance, this doesn't handle
# OS X Terminal windows.
if (not defined &get_fork_TTY # no routine exists,
# of terminal this is,
# window this is,
# on,
{
} ## end if (not defined &get_fork_TTY...
elsif ($^O eq 'os2') { # If this is OS/2,
}
# untaint $^O, which may have been tainted by the last statement.
# see bug [perl #24674]
$^O =~ m/^(.*)\z/; $^O = $1;
# "Here begin the unreadable code. It needs fixing."
=head2 RESTART PROCESSING
This section handles the restart command. When the C<R> command is invoked, it
tries to capture all of the state it can into environment variables, and
then sets C<PERLDB_RESTART>. When we start executing again, we check to see
if C<PERLDB_RESTART> is there; if so, we reload all the information that
the R command stuffed into the environment variables.
PERLDB_RESTART - flag only, contains no restart data itself.
PERLDB_HIST - command history, if it's available
PERLDB_ON_LOAD - breakpoints set by the rc file
PERLDB_VISITED - files that had breakpoints
PERLDB_FILE_... - breakpoints for a file
PERLDB_OPT - active options
PERLDB_INC - the original @INC
PERLDB_PRETYPE - preprompt debugger actions
PERLDB_PRE - preprompt Perl code
PERLDB_POST - post-prompt Perl code
PERLDB_TYPEAHEAD - typeahead captured by readline()
We chug through all these variables and plug the values saved in them
back into the appropriate spots in the debugger.
=cut
if (exists $ENV{PERLDB_RESTART}) {
# We're restarting, so we don't need the flag that says to restart anymore.
delete $ENV{PERLDB_RESTART};
# $restart = 1;
# restore breakpoints/actions
for (0 .. $#had_breakpoints) {
}
# restore options
$val =~ s/[\\\']/\\$1/g;
parse_options("$opt'$val'");
}
# restore original @INC
# return pre/postprompt actions and typeahead buffer
} ## end if (exists $ENV{PERLDB_RESTART...
=head2 SETTING UP THE TERMINAL
Now, we'll decide how the debugger is going to interact with the user.
If there's no TTY, we set the debugger to run non-stop; there's not going
to be anyone there to enter commands.
=cut
if ($notty) {
$runnonstop = 1;
}
=pod
If there is a TTY, we have to determine who it belongs to before we can
proceed. If this is a slave editor or graphical debugger (denoted by
the first command-line switch being '-emacs'), we shift this off and
set C<$rl> to 0 (XXX ostensibly to do straight reads).
=cut
else {
# Is Perl being run from a slave editor or graphical debugger?
# If so, don't use readline, and set $slave_editor = 1.
$slave_editor =
#require Term::ReadLine;
=pod
We then determine what the console should be on various systems:
=over 4
=item * Cygwin - We use C<stdin> instead of a separate device.
=cut
if ($^O eq 'cygwin') {
undef $console;
}
=cut
}
=item * Windows or MSDOS - use C<con>.
=cut
elsif ($^O eq 'dos' or -e "con" or $^O eq 'MSWin32') {
$console = "con";
}
=item * MacOS - use C<Dev:Console:Perl Debug> if this is the MPW version; C<Dev:
Console> if not. (Note that Mac OS X returns 'darwin', not 'MacOS'. Also note that the debugger doesn't do anything special for 'darwin'. Maybe it should.)
=cut
elsif ($^O eq 'MacOS') {
$console =
"Dev:Console:Perl Debug"; # Separate window for application
}
else {
$console = "Dev:Console";
}
} ## end elsif ($^O eq 'MacOS')
=item * VMS - use C<sys$command>.
=cut
else {
# everything else is ...
$console = "sys\$command";
}
=pod
=back
Several other systems don't use a specific console. We C<undef $console>
with a slave editor, Epoc).
=cut
$console = undef;
}
if ($^O eq 'NetWare') {
$console = undef;
}
# In OS/2, we need to use STDIN to get textmode too, even though
# it pretty much looks like Unix otherwise.
{ # In OS/2
$console = undef;
}
# EPOC also falls into the 'got to use STDIN' camp.
if ($^O eq 'epoc') {
$console = undef;
}
=pod
If there is a TTY hanging around from a parent, we use that as the console.
=cut
=head2 SOCKET HANDLING
The debugger is capable of opening a socket and carrying out a debugging
session over the socket.
If C<RemotePort> was defined in the options, the debugger assumes that it
should try to start a debugging session on that port. It builds the socket
and then tries to connect the input and output filehandles to it.
=cut
# Handle socket stuff.
if (defined $remoteport) {
# If RemotePort was defined in the options, connect input and output
# to the socket.
Timeout => '10',
PeerAddr => $remoteport,
Proto => 'tcp',
);
if (!$OUT) { die "Unable to connect to remote host: $remoteport\n"; }
} ## end if (defined $remoteport)
=pod
If no C<RemotePort> was defined, and we want to create a TTY on startup,
this is probably a situation where multiple debuggers are running (for example,
a backticked command that starts up another debugger). We create a new IN and
OUT filehandle, and do the necessary mojo to create a new TTY if we know how
and if we can.
=cut
# Non-socket.
else {
# Two debuggers running (probably a system or a backtick that invokes
# the debugger itself under the running one). create a new IN and OUT
# filehandle, and do the necessary mojo to create a new tty if we
# know how, and we can.
if ($console) {
# If we have a console, check to see if there are separate ins and
# outs to open. (They are assumed identiical if not.)
my ($i, $o) = split /,/, $console;
$o = $i unless defined $o;
open(IN, "+<$i") ||
open(IN, "<$i") ||
open(IN, "<&STDIN");
# or merge with STDERR, or merge with STDOUT.
open(OUT, "+>$o") ||
open(OUT, ">$o") ||
open(OUT, ">&STDERR") ||
} ## end if ($console)
elsif (not defined $console) {
# No console. Open STDIN.
open(IN, "<&STDIN");
# merge with STDERR, or with STDOUT.
open(OUT, ">&STDERR") ||
} ## end elsif (not defined $console)
# Keep copies of the filehandles so that when the pager runs, it
# can close standard input without clobbering ours.
} ## end elsif (from if(defined $remoteport))
# Unbuffer DB::OUT. We need to see responses right away.
$| = 1; # for DB::OUT
select($previous);
# Line info goes to debugger output unless pointed elsewhere.
# Pointing elsewhere makes it possible for slave editors to
# keep track of file and position. We have both a filehandle
# and a I/O description to keep track of.
=pod
To finish initialization, we show the debugger greeting,
and then call the C<afterinit()> subroutine if there is one.
=cut
# Show the debugger greeting.
unless ($runnonstop) {
local $\ = '';
local $, = '';
if ($term_pid eq '-1') {
print $OUT "\nDaughter DB session started...\n";
}
else {
print $OUT "\nLoading DB routines from $header\n";
print $OUT (
"Editor support ",
);
print $OUT
"\nEnter h or `h h' for help, or `$doccmd perldebug' for more help.\n\n";
} ## end else [ if ($term_pid eq '-1')
} ## end unless ($runnonstop)
} ## end else [ if ($notty)
# XXX This looks like a bug to me.
# Why copy to @ARGS and then futz with @args?
for (@args) {
# Make sure backslashes before single quotes are stripped out, and
# keep args unless they are numeric (XXX why?)
s/\'/\\\'/g;
s/(.*)/'$1'/ unless /^-?[\d.]+$/;
}
# If there was an afterinit() sub defined, call it. It will get
# executed in our scope, so it can fiddle with debugger globals.
if (defined &afterinit) { # May be defined in $rcfile
&afterinit();
}
# Inform us about "Stack dump during die enabled ..." in dieLevel().
$I_m_init = 1;
############################################################ Subroutines
=head1 SUBROUTINES
=head2 DB
This gigantic subroutine is the heart of the debugger. Called before every
statement, its job is to determine if a breakpoint has been reached, and
stop if so; read commands from the user, parse them, and execute
them, and hen send execution off to the next statement.
Note that the order in which the commands are processed is very important;
some commands earlier in the loop will actually alter the C<$cmd> variable
to create other commands to be executed later. This is all highly "optimized"
but can be confusing. Check the comments for each C<$cmd ... && do {}> to
see what's happening in any given command.
=cut
sub DB {
# Check for whether we should be running continuously or not.
# _After_ the perl program is compiled, $single is set to 1:
if ($single and not $second_time++) {
# Options say run non-stop. Run until we get an interrupt.
if ($runnonstop) { # Disable until signal
# If there's any call stack in place, turn off single
# stepping into subs throughout the stack.
for ($i = 0 ; $i <= $stack_depth ;) {
$stack[$i++] &= ~1;
}
# And we are now no longer in single-step mode.
$single = 0;
# If we simply returned at this point, we wouldn't get
# the trace info. Fall on through.
# return;
} ## end if ($runnonstop)
elsif ($ImmediateStop) {
# We are supposed to stop here; XXX probably a break.
# us into the command loop
}
} ## end if ($single and not $second_time...
# If we're in single-step mode, or an interrupt (real or fake)
# has occurred, turn off non-stop mode.
# Preserve current values of $@, $!, $^E, $,, $/, $\, $^W.
# The code being debugged may have altered them.
&save;
# Since DB::DB gets called after every line, we can use caller() to
# figure out where we last were executing. Sneaky, eh? This works because
# caller is returning all the extra information when called from the
# debugger.
local $filename_ini = $filename;
# set up the context for DB::eval, so it can properly execute
# code on behalf of the user. We add the package in so that the
# code is eval'ed in the proper package (not in the debugger!).
local $usercontext =
'($@, $!, $^E, $,, $/, $\, $^W) = @saved;' .
"package $package;";
# Create an alias to the active file magical array to simplify
# the code here.
# we need to check for pseudofiles on Mac OS (these are files
# not attached to a filename, but instead stored in Dev:Pseudo)
if ($^O eq 'MacOS' && $#dbline < 0) {
}
# Last line in the program.
local $max = $#dbline;
# if we have something here, see if we should break.
# Stop if the stop criterion says to just stop.
if ($stop eq '1') {
$signal |= 1;
}
# It's a conditional stop; eval it in the user's context and
# see if we should stop. If so, remove the one-time sigil.
elsif ($stop) {
$evalarg = "\$DB::signal |= 1 if do {$stop}";
&eval;
}
} ## end if ($dbline{$line} && ...
# Preserve the current stop-or-not, and see if any of the W
# (watch expressions) has changed.
my $was_signal = $signal;
# If we have any watch expressions ...
if ($trace & 2) {
for (my $n = 0 ; $n <= $#to_watch ; $n++) {
local $onetimeDump; # Tell DB::eval() to not output results
# Fix context DB::eval() wants to return an array, but
# we need a scalar here.
my ($val) =
join ( "', '", &eval );
# Did it change?
# Yep! Show the difference, and fake an interrupt.
$signal = 1;
} ## end if ($val ne $old_watch...
} ## end for (my $n = 0 ; $n <= ...
} ## end if ($trace & 2)
=head2 C<watchfunction()>
C<watchfunction()> is a function that can be defined by the user; it is a
function which will be run on each entry to C<DB::DB>; it gets the
current package, filename, and line as its parameters.
The watchfunction can do anything it likes; it is executing in the
debugger's context, so it has access to all of the debugger's internal
data structures and functions.
C<watchfunction()> can control the debugger's actions. Any of the following
will cause the debugger to return control to the user's program after
C<watchfunction()> executes:
=over 4
=item * Returning a false value from the C<watchfunction()> itself.
=item * Altering C<$single> to a false value.
=item * Altering C<$signal> to a false value.
=item * Turning off the '4' bit in C<$trace> (this also disables the
check for C<watchfunction()>. This can be done with
$trace &= ~4;
=back
=cut
# If there's a user-defined DB::watchfunction, call it with the
# current package, filename, and line. The function executes in
# the DB:: package.
return
and not $single
and not $was_signal
and not($trace & ~4);
} ## end if ($trace & 4)
# Pick up any alteration to $signal in the watchfunction, and
# turn off the signal now.
$was_signal = $signal;
$signal = 0;
=head2 GETTING READY TO EXECUTE COMMANDS
The debugger decides to take control if single-step mode is on, the
C<t> command was entered, or the user generated a signal. If the program
has fallen off the end, we set things up so that entering further commands
won't cause trouble, and we say that the program is over.
=cut
# Check to see if we should grab control ($single true,
# trace set appropriately, or we got a signal).
# Yes, grab control.
if ($slave_editor) {
# Tell the editor to update its position.
$position = "\032\032$filename:$line:0\n";
}
=pod
Special check: if we're in package C<DB::fake>, we've gone through the
C<END> block at least once. We set up everything so that we can continue
to enter commands and have a valid context to be in.
=cut
elsif ($package eq 'DB::fake') {
# Fallen off the end already.
print_help(<<EOP);
# Set the DB::eval context appropriately.
$package = 'main';
$usercontext =
'($@, $!, $^E, $,, $/, $\, $^W) = @saved;' .
"package $package;"; # this won't let them modify, alas
} ## end elsif ($package eq 'DB::fake')
=pod
If the program hasn't finished executing, we scan forward to the
next executable line, print that out, build the prompt from the file and line
number information, and print that.
=cut
else {
# Still somewhere in the midst of execution. Set up the
# debugger prompt.
# Perl 5 ones (sorry, we don't print Klingon
#module names)
$prefix .= "$sub($filename:";
# Break up the prompt if it's really long.
if (length($prefix) > 30) {
$position = "$prefix$line):\n$line:\t$dbline[$line]$after";
$prefix = "";
$infix = ":\t";
}
else {
$infix = "):\t";
$position = "$prefix$line$infix$dbline[$line]$after";
}
# Print current line info, indenting if necessary.
if ($frame) {
"$line:\t$dbline[$line]$after");
}
else {
}
# Scan forward, stopping at either the end or the next
# unbreakable line.
{ #{ vi
# Drop out on null statements, block closers, and comments.
last if $dbline[$i] =~ /^\s*[\;\}\#\n]/;
# Drop out if the user interrupted us.
last if $signal;
# Append a newline if the line doesn't have one. Can happen
# in eval'ed text, for instance.
# Next executable line.
$incr_pos = "$prefix$i$infix$dbline[$i]$after";
if ($frame) {
# Print it indented if tracing is on.
"$i:\t$dbline[$i]$after");
}
else {
}
} ## end for ($i = $line + 1 ; $i...
} ## end else [ if ($slave_editor)
} ## end if ($single || ($trace...
=pod
If there's an action to be executed for the line we stopped at, execute it.
If there are any preprompt actions, execute those as well.
=cut
# If there's an action, do it now.
# Are we nested another level (e.g., did we evaluate a function
# that had a breakpoint in it at the debugger prompt)?
if ($single || $was_signal) {
# Yes, go down a level.
# Do any pre-prompt actions.
&eval;
}
# Complain about too much recursion if we passed the limit.
if $single & 4;
# The line we're currently on. Set $incr to -1 to stay here
# until we get a command that tells us to advance.
# Tack preprompt debugger actions ahead of any actual input.
=head2 WHERE ARE WE?
XXX Relocate this section?
The debugger normally shows the line corresponding to the current line of
execution. Sometimes, though, we want to see the next line, or to move elsewhere
in the file. This is done via the C<$incr>, C<$start>, and C<$max> variables.
C<$incr> controls by how many lines the "current" line should move forward
after a command is executed. If set to -1, this indicates that the "current"
line shouldn't change.
C<$start> is the "current" line. It is used for things like knowing where to
move forwards or backwards from when doing an C<L> or C<-> command.
C<$max> tells the debugger where the last line of the current file is. It's
used to terminate loops most often.
=head2 THE COMMAND LOOP
Most of C<DB::DB> is actually a command parsing and dispatch loop. It comes
in two parts:
=over 4
=item * The outer part of the loop, starting at the C<CMD> label. This loop
reads a command and then executes it.
=item * The inner part of the loop, starting at the C<PIPE> label. This part
is wholly contained inside the C<CMD> block and only executes a command.
Used to handle commands running inside a pager.
=back
So why have two labels to restart the loop? Because sometimes, it's easier to
have a command I<generate> another command and then re-execute the loop to do
the new command. This is faster, but perhaps a bit more convoluted.
=cut
# The big command dispatch loop. It keeps running until the
# user yields up control again.
#
# If we have a terminal for input, and we get something back
# from readline(), keep on processing.
CMD:
while (
# We have a terminal, or can get one ...
# ... and it belogs to this PID or we get one for this PID ...
# ... and we got a line of command input ...
defined(
)
)
)
{
# ... try to execute the input as debugger commands.
# Don't stop running.
$single = 0;
# No signal is active.
$signal = 0;
# Handle continued commands (ending with \):
$cmd =~ s/\\$/\n/ && do {
redo CMD;
};
we'll do nothing below (no command will match). If there was, we also save it
=cut
# Empty input means repeat the last command.
chomp($cmd); # get rid of the annoying extra newline
# This is a restart point for commands that didn't arrive
# via direct user input. It allows us to 'redo PIPE' to
# re-execute command processing without reading a new command.
PIPE: {
$cmd =~ s/^\s+//s; # trim annoying leading whitespace
$cmd =~ s/\s+$//s; # trim annoying trailing whitespace
($i) = split (/\s+/, $cmd);
=cut
# See if there's an alias for the command, and set it up if so.
if ($alias{$i}) {
# Squelch signal handling; we want to keep control here
# if something goes loco during the alias eval.
# This is a command, so we eval it in the DEBUGGER's
# scope! Otherwise, we can't see the special debugger
# variables, or get to the debugger's subs. (Well, we
# _could_, but why make it even more complicated?)
eval "\$cmd =~ $alias{$i}";
if ($@) {
local $\ = '';
print $OUT "Couldn't evaluate `$i' alias: $@";
next CMD;
}
} ## end if ($alias{$i})
=cut
$cmd =~ /^q$/ && do {
$fall_off_end = 1;
clean_ENV();
exit $?;
};
=cut
$cmd =~ /^t$/ && do {
$trace ^= 1;
local $\ = '';
"\n";
next CMD;
};
=cut
$cmd =~ /^S(\s+(!)?(.+))?$/ && do {
# Need to make these sane here.
local $\ = '';
local $, = '';
# Search through the debugger's magical hash of subs.
# If $nocheck is true, just print the sub name.
# Otherwise, check it against the pattern. We then use
# the XOR trick to reverse the condition as required.
}
}
next CMD;
};
=cut
=cut
# Bare V commands get the currently-being-debugged package
# added.
$cmd =~ /^V$/ && do {
$cmd = "V $package";
};
# V - show variables in package.
$cmd =~ /^V\b\s*(\S+)\s*(.*)/ && do {
# Save the currently selected filehandle and
# force output to debugger's filehandle (dumpvar
# just does "print" for output).
# Grab package name and variables to dump.
$packname = $1;
# If main::dumpvar isn't here, get it.
# for the moment, along with return values.
local $frame = 0;
local $doret = -2;
# must detect sigpipe failures - not catching
# then will cause the debugger to die.
eval {
$packname,
: -1, # assume -1 unless specified
@vars
);
};
# The die doesn't need to include the $@, because
# it will automatically get propagated for us.
if ($@) {
}
} ## end if (defined &main::dumpvar)
else {
# Couldn't load dumpvar.
print $OUT "dumpvar.pl not available.\n";
}
# Restore the output filehandle, and go round again.
select($savout);
next CMD;
};
=cut
$cmd =~ s/^x\b/ / && do { # Remainder gets done by DB::eval()
# handle special "x 3 blah" syntax XXX propagate
# doc back to special variables.
if ($cmd =~ s/^\s*(\d+)(?=\s)/ /) {
$onetimedumpDepth = $1;
}
};
=cut
$cmd =~ s/^m\s+([\w:]+)\s*$/ / && do {
methods($1);
next CMD;
};
# m expr - set up DB::eval to do the work
$cmd =~ s/^m\b/ / && do { # Rest gets done by DB::eval()
};
=cut
$cmd =~ /^f\b\s*(.*)/ && do {
$file = $1;
$file =~ s/\s+$//;
# help for no arguments (old-style was return from sub).
if (!$file) {
print $OUT
"The old f command is now the r command.\n"; # hint
print $OUT "The new f command switches filenames.\n";
next CMD;
} ## end if (!$file)
# if not in magic file list, try a close match.
if (($try) = grep(m#^_<.*$file#, keys %main::)) {
{
print $OUT
"Choosing $try matching `$file':\n";
}
} ## end if (($try) = grep(m#^_<.*$file#...
} ## end if (!defined $main::{ ...
# If not successfully switched now, we failed.
print $OUT "No file matching `$file' is loaded.\n";
next CMD;
}
# We switched, so switch the debugger internals around.
$max = $#dbline;
$start = 1;
$cmd = "l";
} ## end elsif ($file ne $filename)
# We didn't switch; say we didn't.
else {
print $OUT "Already in $file.\n";
next CMD;
}
};
=cut
# . command.
$cmd =~ /^\.$/ && do {
# Reset everything to the old location.
$filename = $filename_ini;
$max = $#dbline;
# Now where are we?
next CMD;
};
=cut
# - - back a window.
$cmd =~ /^-$/ && do {
# back up by a window; go to 1 if back too far.
# Generate and execute a "l +" command (handled below).
};
=head3 PRE-580 COMMANDS VS. NEW COMMANDS: C<a, A, b, B, h, l, L, M, o, O, P, v, w, W, E<lt>, E<lt>E<lt>, {, {{>
=cut
# All of these commands were remapped in perl 5.8.0;
# we send them off to the secondary dispatcher (see below).
next CMD;
};
=cut
$cmd =~ /^y(?:\s+(\d*)\s*(.*))?$/ && do {
# See if we've got the necessary support.
or &warn(
$@ =~ /locate/
? "PadWalker module not found - please install\n"
: $@
)
and next CMD;
# Load up dumpvar if we don't have it. If we can, that is.
or print $OUT "dumpvar.pl not available.\n"
and next CMD;
# Got all the modules we need. Find them and print them.
# Find the pad.
# Oops. Can't find it.
# Show the desired vars with dumplex().
# Have dumplex dump the lexicals.
$_,
$h->{$_},
@vars
) for sort keys %$h;
select($savout);
next CMD;
};
demarcation' above which commands can be entered anytime, and below which
=cut
# n - next
$cmd =~ /^n$/ && do {
# Single step, but don't enter subs.
$single = 2;
# Save for empty command (repeat last).
last CMD;
};
=cut
# s - single step.
$cmd =~ /^s$/ && do {
# Get out and restart the command loop if program
# has finished.
# Single step should enter subs.
$single = 1;
# Save for empty command (repeat last).
last CMD;
};
=cut
# c - start continuous execution.
$cmd =~ /^c\b\s*([\w:]*)\s*$/ && do {
# Hey, show's over. The debugged program finished
# executing already.
# Capture the place to put a one-time break.
$subname = $i = $1;
# Probably not needed, since we finish an interactive
# sub-session anyway...
# local $filename = $filename;
# local *dbline = *dbline; # XXX Would this work?!
#
# The above question wonders if localizing the alias
# to the magic array works or not. Since it's commented
# out, we'll just leave that to speculation for now.
# If the "subname" isn't all digits, we'll assume it
# is a subroutine name, and try to find it.
if ($subname =~ /\D/) { # subroutine name
# Qualify it to the current package unless it's
# already qualified.
unless $subname =~ /::/;
# find_sub will return "file:line_number" corresponding
# to where the subroutine is defined; we call find_sub,
# break up the return value, and assign it in one
# operation.
# Force the line number to be numeric.
$i += 0;
# If we got a line number, we found the sub.
if ($i) {
# Switch all the debugger's internals around so
# we're actually working with that file.
# Mark that there's a breakpoint in this file.
# Scan forward to the first executable line
# after the 'sub whatever' line.
$max = $#dbline;
} ## end if ($i)
# We didn't find a sub by that name.
else {
print $OUT "Subroutine $subname not found.\n";
next CMD;
}
} ## end if ($subname =~ /\D/)
# At this point, either the subname was all digits (an
# absolute line-break request) or we've scanned through
# the code following the definition of the sub, looking
# for an executable, which we may or may not have found.
#
# If $i (which we set $subname from) is non-zero, we
# got a request to break at some line somewhere. On
# one hand, if there wasn't any real subroutine name
# involved, this will be a request to break in the current
# file at the specified line, so we have to check to make
# sure that the line specified really is breakable.
#
# On the other hand, if there was a subname supplied, the
# preceeding block has moved us to the proper file and
# location within that file, and then scanned forward
# looking for the next executable line. We have to make
# sure that one was found.
#
# On the gripping hand, we can't do anything unless the
# current value of $i points to a valid breakable line.
# Check that.
if ($i) {
# Breakable?
if ($dbline[$i] == 0) {
print $OUT "Line $i not breakable.\n";
next CMD;
}
# Yes. Set up the one-time-break sigil.
$dbline{$i} =~
s/($|\0)/;9$1/; # add one-time-only b.p.
} ## end if ($i)
# Turn off stack tracing from here up.
for ($i = 0 ; $i <= $stack_depth ;) {
$stack[$i++] &= ~1;
}
last CMD;
};
=cut
# r - return from the current subroutine.
$cmd =~ /^r$/ && do {
# Can't do anythign if the program's over.
# Turn on stack trace.
# Print return value unless the stack is empty.
last CMD;
};
=cut
# R - restart execution.
$cmd =~ /^R$/ && do {
# I may not be able to resurrect you, but here goes ...
print $OUT
"Warning: some settings and command-line options may be lost!\n";
# If warn was on before, turn it on again.
# Rebuild the -I flags that were on the initial
# command line.
for (@ini_INC) {
push @flags, '-I', $_;
}
# Turn on taint if it was on before.
# Arrange for setting the old INC:
# Save the current @init_INC in the environment.
# If this was a perl one-liner, go to the "file"
# corresponding to the one-liner read all the lines
# out of it (except for the first one, which is going
# to be added back on again when 'perl -d' runs: that's
# the 'require perl5db.pl;' line), and add them back on
# to the command line to be executed.
if ($0 eq '-e') {
for (1 .. $#{'::_<-e'}) { # The first line is PERL5DB
chomp($cl = ${'::_<-e'}[$_]);
}
} ## end if ($0 eq '-e')
# Otherwise we just reuse the original name we had
# before.
else {
@script = $0;
}
=pod
After the command line has been reconstructed, the next step is to save
the debugger's status in environment variables. The C<DB::set_list> routine
is used to save aggregate variables (both hashes and arrays); scalars are
just popped into environment variables directly.
=cut
# If the terminal supported history, grab it and
# save that in the environment.
set_list("PERLDB_HIST",
? $term->GetHistory
: @hist);
# Find all the files that were visited during this
# session (i.e., the debugger had magic hashes
# corresponding to them) and stick them in the environment.
my @had_breakpoints = keys %had_breakpoints;
# Save the debugger options we chose.
# Save the break-on-loads.
=pod
The most complex part of this is the saving of all of the breakpoints. They
can live in an awful lot of places, and we have to go through all of them,
find the breakpoints, and then save them in the appropriate environment
variable via C<DB::set_list>.
=cut
# Go through all the breakpoints and make sure they're
# still valid.
my @hard;
for (0 .. $#had_breakpoints) {
# We were in this file.
my $file = $had_breakpoints[$_];
# Grab that file's magic line hash.
# Skip out if it doesn't exist, or if the breakpoint
# is in a postponed file (we'll do postponed ones
# later).
# In an eval. This is a little harder, so we'll
# do more processing on that below.
if $file =~ /^\(\w*eval/;
# XXX I have no idea what this is doing. Yet.
my @add;
if $postponed_file{$file};
# Save the list of all the breakpoints for this file.
} ## end for (0 .. $#had_breakpoints)
# The breakpoint was inside an eval. This is a little
# more difficult. XXX and I don't understand it.
for (@hard) {
# Get over to the eval in question.
}
unless (%subs) {
print $OUT
"No subroutines in $_, ignoring breakpoints.\n";
next;
}
# One breakpoint per sub only:
if (
$line # Not after the subroutine
and (
not defined $offset # Not caught
or $offset < 0
)
)
{ # or badly caught
if $offset >= 0;
} ## end if ($subs{$sub}->[1] >=...
} ## end for $sub (keys %subs)
if (defined $offset) {
"break $offset if $dbline{$line}";
}
else {
print $OUT
"Breakpoint in $_:$line ignored: after all the subroutines.\n";
}
} ## end for $line (keys %dbline)
} ## end for (@hard)
# Save the other things that don't need to be
# processed.
# We are oficially restarting.
# We are junking all child debuggers.
# Set this back to the initial pid.
=pod
After all the debugger status has been saved, we take the command we built
up and then C<exec()> it. The debugger will spot the C<PERLDB_RESTART>
environment variable and realize it needs to reload its state from the
environment.
=cut
# And run Perl again. Add the "-d" flag, all the
# flags we built up, the script (whether a one-liner
# or a file), add on the -emacs flag for a slave editor,
# and then the old arguments. We use exec() to keep the
# PID stable (and that way $ini_pids is still valid).
print $OUT "exec failed: $!\n";
last CMD;
};
=cut
$cmd =~ /^T$/ && do {
next CMD;
};
=cut
=cut
=cut
$cmd =~ /^\/(.*)$/ && do {
# The pattern as a string.
$inpat = $1;
# Remove the final slash.
$inpat =~ s:([^\\])/$:$1:;
# If the pattern isn't null ...
if ($inpat ne "") {
# Turn of warn and die procesing for a bit.
# Create the pattern.
eval '$inpat =~ m' . "\a$inpat\a";
if ($@ ne "") {
# Oops. Bad pattern. No biscuit.
# Print the eval error and go back for more
# commands.
print $OUT "$@";
next CMD;
}
} ## end if ($inpat ne "")
# Set up to stop on wrap-around.
# Don't move off the current line.
$incr = -1;
# Done in eval so nothing breaks if the pattern
# does something weird.
eval '
for (;;) {
# Move ahead one line.
++$start;
# Wrap if we pass the last line.
# Stop if we have gotten back to this line again,
# A hit! (Note, though, that we are doing
# case-insensitive matching. Maybe a qr//
# expression would be better, so the user could
# do case-sensitive matching if desired.
if ($slave_editor) {
# Handle proper escaping in the slave.
print $OUT "\032\032$filename:$start:0\n";
}
else {
# Just print the line normally.
}
# And quit since we found something.
last;
}
} ';
# If we wrapped, there never was a match.
next CMD;
};
=cut
# ? - backward pattern search.
$cmd =~ /^\?(.*)$/ && do {
# Get the pattern, remove trailing question mark.
$inpat = $1;
$inpat =~ s:([^\\])\?$:$1:;
# If we've got one ...
if ($inpat ne "") {
# Turn off die & warn handlers.
eval '$inpat =~ m' . "\a$inpat\a";
if ($@ ne "") {
# Ouch. Not good. Print the error.
print $OUT $@;
next CMD;
}
} ## end if ($inpat ne "")
# Where we are now is where to stop after wraparound.
# Don't move away from this line.
$incr = -1;
# Search inside the eval to prevent pattern badness
# from killing us.
eval '
for (;;) {
# Back up a line.
--$start;
# Wrap if we pass the first line.
# Quit if we get back where we started,
# Match?
if ($slave_editor) {
# Yep, follow slave editor requirements.
print $OUT "\032\032$filename:$start:0\n";
}
else {
# Yep, just print normally.
}
# Found, so done.
last;
}
} ';
# Say we failed if the loop never found anything,
next CMD;
};
=cut
# $rc - recall command.
# No arguments, take one thing off history.
# Relative (- found)?
# Y - index back from most recent (by 1 if bare minus)
# N - go to that particular command slot or the last
# thing if nothing following.
$i = $1 ? ($#hist - ($2 || 1)) : ($2 || $#hist);
# Pick out the command desired.
# Print the command to be executed and restart the loop
# with that command in the buffer.
redo CMD;
};
=cut
# $sh$sh - run a shell command (if it's all ASCII).
# Can't run shell commands with Unicode in the debugger, hmm.
# System it.
&system($1);
next CMD;
};
=cut
# $rc pattern $rc - find a command in the history.
# Create the pattern to use.
$pat = "^$1";
# Toss off last entry if length is >1 (and it always is).
# Look backward through the history.
for ($i = $#hist ; $i ; --$i) {
# Stop if we find it.
}
if (!$i) {
# Never found it.
print $OUT "No such command!\n\n";
next CMD;
}
# Found it. Put it in the buffer, print it, and process it.
redo CMD;
};
=cut
# $sh - start a shell.
# Run the user's shell. If none defined, run Bourne.
# We resume execution when the shell terminates.
next CMD;
};
=cut
# $sh command - start a shell and run a command in it.
# XXX: using csh or tcsh destroys sigint retvals!
#&system($1); # use this instead
# use the user's shell, or Bourne if none defined.
next CMD;
};
=cut
$cmd =~ /^H\b\s*(-(\d+))?/ && do {
# Anything other than negative numbers is ignored by
# the (incorrect) pattern, so this test does nothing.
# Set to the minimum if less than zero.
# Start at the end of the array.
# Stay in while we're still above the ending value.
# Tick back by one each time around the loop.
for ($i = $#hist ; $i > $end ; $i--) {
# Print the command unless it has no arguments.
unless $hist[$i] =~ /^.?$/;
}
next CMD;
};
=cut
# man, perldoc, doc - show manual pages.
runman($1);
next CMD;
};
=head4 C<p> - print
=cut
# p - print (no args): print $_.
# p - print the given expression.
=cut
# = - set up a command alias.
$cmd =~ s/^=\s*// && do {
my @keys;
if (length $cmd == 0) {
# No args, get current aliases.
}
elsif (my ($k, $v) = ($cmd =~ /^(\S+)\s+(\S.*)/)) {
# Creating a new alias. $k is alias name, $v is
# alias value.
# can't use $_ or kill //g state
for my $x ($k, $v) {
# Escape "alarm" characters.
$x =~ s/\a/\\a/g
}
# Substitute key for value, using alarm chars
# as separators (which is why we escaped them in
# the command).
$alias{$k} = "s\a$k\a$v\a";
# Turn off standard warn and die behavior.
# Is it valid Perl?
unless (eval "sub { s\a$k\a$v\a }; 1") {
# Nope. Bad alias. Say so and get out.
print $OUT "Can't alias $k to $v: $@\n";
delete $alias{$k};
next CMD;
}
# We'll only list the new one.
@keys = ($k);
} ## end elsif (my ($k, $v) = ($cmd...
# The argument is the alias to list.
else {
}
# List aliases.
for my $k (@keys) {
# Messy metaquoting: Trim the substiution code off.
# We use control-G as the delimiter because it's not
# likely to appear in the alias.
if ((my $v = $alias{$k}) =~ ss\a$k\a(.*)\a$1) {
# Print the alias.
print $OUT "$k\t= $1\n";
}
elsif (defined $alias{$k}) {
# Couldn't trim it off; just print the alias code.
print $OUT "$k\t$alias{$k}\n";
}
else {
# No such, dude.
print "No alias for $k\n";
}
} ## end for my $k (@keys)
next CMD;
};
=cut
# source - read commands from a file (or pipe!) and execute.
if (open my $fh, $1) {
# Opened OK; stick it in the list of file handles.
}
else {
# Couldn't open it.
&warn("Can't execute `$1': $!\n");
}
next CMD;
};
=cut
# save source - write commands to a file for later use
if (open my $fh, "> $file") {
# chomp to remove extraneous newlines from source'd files
print "commands saved in $file\n";
} else {
&warn("Can't save debugger commands in '$1': $!\n");
}
next CMD;
};
=cut
# || - run command in the pager, with output to DB::OUT.
$cmd =~ /^\|\|?\s*[^|]/ && do {
if ($pager =~ /^\|/) {
# Default pager is into a pipe. Redirect I/O.
open(SAVEOUT, ">&STDOUT") ||
&warn("Can't save STDOUT");
open(STDOUT, ">&OUT") ||
&warn("Can't redirect STDOUT");
} ## end if ($pager =~ /^\|/)
else {
# Not into a pipe. STDOUT is safe.
}
# Fix up environment to record we have less if so.
fix_less();
# Couldn't open pipe to pager.
&warn("Can't pipe output to `$pager'");
if ($pager =~ /^\|/) {
# Redirect I/O back again.
|| &warn("Can't restore DB::OUT");
open(STDOUT, ">&SAVEOUT") ||
&warn("Can't restore STDOUT");
close(SAVEOUT);
} ## end if ($pager =~ /^\|/)
else {
# Redirect I/O. STDOUT already safe.
|| &warn("Can't restore DB::OUT");
}
next CMD;
} ## end unless ($piped = open(OUT,...
# Set up broken-pipe handler if necessary.
if $pager =~ /^\|/ &&
# Save current filehandle, unbuffer out, and put it back.
$| = 1;
# Don't put it back if pager was a pipe.
# Trim off the pipe symbols and run the command now.
$cmd =~ s/^\|+\s*//;
redo PIPE;
};
=cut
# t - turn trace on.
# s - single-step. Remember the last command was 's'.
# n - single-step, but not into subs. Remember last command
# was 'n'.
} # PIPE:
# Make sure the flag that says "the debugger's running" is
# still on, to make sure we get control again.
$evalarg = "\$^D = \$^D | \$DB::db_stop;\n$cmd";
# Run *our* eval that executes in the caller's context.
&eval;
# Turn off the one-time-dump stuff now.
if ($onetimeDump) {
$onetimeDump = undef;
$onetimedumpDepth = undef;
}
elsif ($term_pid == $$) {
# XXX If this is the master pid, print a newline.
print $OUT "\n";
}
} ## end while (($term || &setterm...
=cut
continue { # CMD:
# At the end of every command:
if ($piped) {
# Unhook the pipe mechanism now.
if ($pager =~ /^\|/) {
# No error from the child.
$? = 0;
# we cannot warn here: the handle is missing --tchrist
# most of the $? crud was coping with broken cshisms
# $? is explicitly set to 0, so this never runs.
if ($?) {
print SAVEOUT "Pager `$pager' failed: ";
if ($? == -1) {
print SAVEOUT "shell returned -1\n";
}
elsif ($? >> 8) {
print SAVEOUT ($? & 127)
? " (SIG#" . ($? & 127) . ")"
: "", ($? & 128) ? " -- core dumped" : "", "\n";
}
else {
}
} ## end if ($?)
# Reopen filehandle for our output (if we can) and
# restore STDOUT (if we can).
open(STDOUT, ">&SAVEOUT") ||
&warn("Can't restore STDOUT");
# Turn off pipe exception handler if necessary.
# Will stop ignoring SIGPIPE if done like nohup(1)
# does SIGINT but Perl doesn't give us a choice.
} ## end if ($pager =~ /^\|/)
else {
# Non-piped "pager". Just restore STDOUT.
}
# Close filehandle pager was using, restore the normal one
# if necessary,
close(SAVEOUT);
# No pipes now.
$piped = "";
} ## end if ($piped)
} # CMD:
=cut
# No more commands? Quit.
# Evaluate post-prompt commands.
&eval;
}
} # if ($single || $signal)
# Put the user's globals back where you found them.
($@, $!, $^E, $,, $/, $\, $^W) = @saved;
();
} ## end sub DB
# The following code may be executed now:
# BEGIN {warn 4}
=head2 sub
C<sub> is called whenever a subroutine call happens in the program being
debugged. The variable C<$DB::sub> contains the name of the subroutine
being called.
The core function of this subroutine is to actually call the sub in the proper
context, capturing its output. This of course causes C<DB::DB> to get called
again, repeating until the subroutine ends and returns control to C<DB::sub>
again. Once control returns, C<DB::sub> figures out whether or not to dump the
return value, and returns its captured copy of the return value as its own
return value. The value then feeds back into the program being debugged as if
C<DB::sub> hadn't been there at all.
C<sub> does all the work of printing the subroutine entry and exit messages
enabled by setting C<$frame>. It notes what sub the autoloader got called for,
and also prints the return value if needed (for the C<r> command and if
the 16 bit is set in C<$frame>).
It also tracks the subroutine call depth by saving the current setting of
C<$single> in the C<@stack> package global; if this exceeds the value in
C<$deep>, C<sub> automatically turns on printing of the current depth by
setting the 4 bit in C<$single>. In any case, it keeps the current setting
=head3 C<caller()> support
If C<caller()> is called from the package C<DB>, it provides some
additional data, in the following order:
=over 4
=item * C<$package>
The package name the sub was in
=item * C<$filename>
The filename it was defined in
=item * C<$line>
The line number it was defined on
=item * C<$subroutine>
The subroutine name; C<'(eval)'> if an C<eval>().
=item * C<$hasargs>
1 if it has arguments, 0 if not
=item * C<$wantarray>
1 if array context, 0 if scalar context
=item * C<$evaltext>
The C<eval>() text, if any (undefined for C<eval BLOCK>)
=item * C<$is_require>
frame was created by a C<use> or C<require> statement
=item * C<$hints>
pragma information; subject to change between versions
=item * C<$bitmask>
pragma information: subject to change between versions
=item * C<@DB::args>
arguments with which the subroutine was invoked
=back
=cut
sub sub {
# Whether or not the autoloader was running, a scalar to put the
# sub's return value in (if needed), and an array to put the sub's
# return value in (if needed).
# If the last ten characters are C'::AUTOLOAD', note we've traced
# into AUTOLOAD for $sub.
$al = " for $$sub";
}
# We stack the stack pointer and then increment it to protect us
# from a situation that might unwind a whole bunch of call frames
# at once. Localizing the stack pointer means that it will automatically
# unwind the same amount when multiple stack frames are unwound.
# Expand @stack.
$#stack = $stack_depth;
# Save current single-step setting.
# Turn off all flags except single-stepping.
$single &= 1;
# If we've gotten really deeply recursed, turn on the flag that will
# make us stop with the 'deep recursion' message.
# If frame messages are on ...
(
? (
# Why -1? But it works! :-(
# Because print_trace will call add 1 to it and then call
# dump_trace; this results in our skipping -1+1 = 0 stack frames
# in dump_trace.
)
# standard frame entry message
)
if $frame;
# Determine the sub's return type,and capture approppriately.
if (wantarray) {
# Called in array context. call sub and capture output.
# DB::DB will recursively get control again if appropriate; we'll come
# back here when the sub is finished.
# Pop the single-step value back off the stack.
# Check for exit trace messages...
(
? (
)
# Standard exit message
)
if $frame & 2;
# Print the return info if we need to.
# Turn off output record separator.
local $\ = '';
# Indent if we're printing because of $frame tracing.
# Print the return value.
print $fh "list context return from $sub:\n";
# And don't print it again.
$doret = -2;
} ## end if ($doret eq $stack_depth...
# And we have to return the return value now.
@ret;
} ## end if (wantarray)
# Scalar context.
else {
if (defined wantarray) {
# Save the value if it's wanted at all.
}
else {
# Void return, explicitly.
&$sub;
undef $ret;
}
# Pop the single-step value off the stack.
# If we're doing exit messages...
(
? (
)
# Standard messages
)
if $frame & 2;
# If we are supposed to show the return value... same as before.
local $\ = '';
print $fh (
defined wantarray
? "scalar context return from $sub: "
: "void context return from $sub\n"
);
$doret = -2;
} ## end if ($doret eq $stack_depth...
# Return the appropriate scalar value.
$ret;
} ## end else [ if (wantarray)
} ## end sub sub
=head1 EXTENDED COMMAND HANDLING AND THE COMMAND API
In Perl 5.8.0, there was a major realignment of the commands and what they did,
Most of the changes were to systematize the command structure and to eliminate
commands that threw away user input without checking.
The following sections describe the code added to make it easy to support
multiple command sets with conflicting command names. This section is a start
at unifying all command processing to make it simpler to develop commands.
Note that all the cmd_[a-zA-Z] subroutines require the command name, a line
number, and C<$dbline> (the current line) as arguments.
Support functions in this section which have multiple modes of failure C<die>
on error; the rest simply return a false value.
The user-interface functions (all of the C<cmd_*> functions) just output
error messages.
=head2 C<%set>
The C<%set> hash defines the mapping from command letter to subroutine
name suffix.
C<%set> is a two-level hash, indexed by set name and then by command name.
Note that trying to set the CommandSet to 'foobar' simply results in the
5.8.0 command set being used, since there's no top-level entry for 'foobar'.
=cut
### The API section
my %set = ( #
'pre580' => {
'a' => 'pre580_a',
'A' => 'pre580_null',
'b' => 'pre580_b',
'B' => 'pre580_null',
'd' => 'pre580_null',
'D' => 'pre580_D',
'h' => 'pre580_h',
'M' => 'pre580_null',
'O' => 'o',
'o' => 'pre580_null',
'v' => 'M',
'w' => 'v',
'W' => 'pre580_W',
},
'pre590' => {
'<' => 'pre590_prepost',
'<<' => 'pre590_prepost',
'>' => 'pre590_prepost',
'>>' => 'pre590_prepost',
'{' => 'pre590_prepost',
'{{' => 'pre590_prepost',
},
);
=head2 C<cmd_wrapper()> (API)
C<cmd_wrapper()> allows the debugger to switch command sets
depending on the value of the C<CommandSet> option.
It tries to look up the command in the X<C<%set>> package-level I<lexical>
(which means external entities can't fiddle with it) and create the name of
the sub to call based on the value found in the hash (if it's there). I<All>
of the commands to be handled in a set have to be added to C<%set>; if they
aren't found, the 5.8.0 equivalent is called (if there is one).
This code uses symbolic references.
=cut
sub cmd_wrapper {
my $cmd = shift;
my $line = shift;
my $dblineno = shift;
# Assemble the command subroutine's name by looking up the
# command set and command name in %set. If we can't find it,
# default to the older version of the command.
my $call = 'cmd_'
# Call the command subroutine, call it by name.
} ## end sub cmd_wrapper
=cut
sub cmd_a {
my $cmd = shift;
my $dbline = shift;
# If it's dot (here), or not all digits, use the current line.
# Should be a line number followed by an expression.
if ($line =~ /^\s*(\d*)\s*(\S.+)/) {
# If we have an expression ...
if (length $expr) {
# ... but the line isn't breakable, complain.
print $OUT
"Line $lineno($dbline[$lineno]) does not have an action?\n";
}
else {
# It's executable. Record that the line has an action.
# Remove any action, temp breakpoint, etc.
# Add the action to the line.
}
} ## end if (length $expr)
} ## end if ($line =~ /^\s*(\d*)\s*(\S.+)/)
else {
# Syntax wrong.
print $OUT
"Adding an action requires an optional lineno and an expression\n"
; # hint
}
} ## end sub cmd_a
subroutine, C<delete_action>.
=cut
sub cmd_A {
my $cmd = shift;
my $line = shift || '';
my $dbline = shift;
# Dot is this line.
# Call delete_action with a null param to delete them all.
# The '1' forces the eval to be true. It'll be false only
# if delete_action blows up for some reason, in which case
# we print $@ and get out.
if ($line eq '*') {
}
# There's a real line number. Pass it to delete_action.
# Error trapping is as above.
elsif ($line =~ /^(\S.*)/) {
}
# Swing and a miss. Bad syntax.
else {
print $OUT
"Deleting an action requires a line number, or '*' for all\n"
; # hint
}
} ## end sub cmd_A
couldn't have had an action). If it is, we just take the action off (this
=cut
sub delete_action {
my $i = shift;
if (defined($i)) {
# Can there be one?
# Nuke whatever's there.
}
else {
print $OUT "Deleting all actions...\n";
for my $file (keys %had_breakpoints) {
my $max = $#dbline;
my $was;
for ($i = 1 ; $i <= $max ; $i++) {
if (defined $dbline{$i}) {
}
delete $had_breakpoints{$file};
}
} ## end for ($i = 1 ; $i <= $max...
} ## end for my $file (keys %had_breakpoints)
} ## end else [ if (defined($i))
} ## end sub delete_action
=cut
sub cmd_b {
my $cmd = shift;
my $line = shift; # [.|line] [cond]
my $dbline = shift;
# Make . the current line number if it's there..
# No line number, no condition. Simple break on current line.
if ($line =~ /^\s*$/) {
}
# Break on load for a file.
my $file = $1;
$file =~ s/\s+$//;
&cmd_b_load($file);
}
# b compile|postpone <some sub> [<condition>]
# The interpreter actually traps this one for us; we just put the
# necessary condition in the %postponed hash.
# Capture the condition if there is one. Make it true if none.
# Save the sub name and set $break to 1 if $1 was 'postpone', 0
# if it was 'compile'.
# De-Perl4-ify the name - ' separators to ::.
$subname =~ s/\'/::/g;
# Qualify it into the current package unless it's already qualified.
# Add main if it starts with ::.
# Save the break type for this sub.
} ## end elsif ($line =~ ...
# b <sub name> [<condition>]
elsif ($line =~ /^([':A-Za-z_][':\w]*(?:\[.*\])?)\s*(.*)/) {
#
$subname = $1;
}
# b <line> [<condition>].
elsif ($line =~ /^(\d*)\s*(.*)/) {
# Capture the line. If none, it's the current line.
# If there's no condition, make it '1'.
# Break on line.
}
# Line didn't make sense.
else {
print "confused by line($line)?\n";
}
} ## end sub cmd_b
C<%had_breakpoints>.
=cut
sub break_on_load {
my $file = shift;
}
=cut
sub report_break_on_load {
sort keys %break_on_load;
}
=cut
sub cmd_b_load {
my $file = shift;
my @files;
# This is a block because that way we can use a redo inside it
# even without there being any looping structure at all outside it.
{
# Save short name and full path if found.
# Tack on .pm and do it again unless there was a '.' in the name
# already.
}
# Do the real work here.
break_on_load($_) for @files;
# All the files that have break-on-load breakpoints.
# Normalize for the purposes of our printing this.
local $\ = '';
local $" = ' ';
print $OUT "Will stop on load of `@files'.\n";
} ## end sub cmd_b_load
=over 4
=item * Localizes C<$filename_error> and sets it to the name of the file to be processed.
=item * Localizes the C<*dbline> glob and reassigns it to point to the file we want to process.
=item * Calls the first function.
The first function works on the "current" (i.e., the one we changed to) file,
and prints C<$filename_error> in the error message (the name of the other file)
if it needs to. When the functions return, C<*dbline> is restored to point to the actual current file (the one we're executing in) and C<$filename_error> is
restored to C<''>. This restores everything to the way it was before the
second function was called at all.
See the comments in C<breakable_line> and C<breakable_line_in_file> for more
details.
=back
=cut
$filename_error = '';
=cut
sub breakable_line {
# $i is the start point. (Where are the FORTRAN programs of yesteryear?)
my $i = $from;
# If there are at least 2 arguments, we're trying to search a range.
if (@_ >= 2) {
# $delta is positive for a forward search, negative for a backward one.
# Keep us from running off the ends of the file.
# Clever test. If you're a mathematician, it's obvious why this
# test works. If not:
# If $delta is positive (going forward), $limit will be $#dbline.
# If $to is less than $limit, ($limit - $to) will be positive, times
# $delta of 1 (positive), so the result is > 0 and we should use $to
# as the stopping point.
#
# If $to is greater than $limit, ($limit - $to) is negative,
# times $delta of 1 (positive), so the result is < 0 and we should
# use $limit ($#dbline) as the stopping point.
#
# If $delta is negative (going backward), $limit will be 1.
# If $to is zero, ($limit - $to) will be 1, times $delta of -1
# (negative) so the result is > 0, and we use $to as the stopping
# point.
#
# If $to is less than zero, ($limit - $to) will be positive,
# times $delta of -1 (negative), so the result is not > 0, and
# we use $limit (1) as the stopping point.
#
# If $to is 1, ($limit - $to) will zero, times $delta of -1
# (negative), still giving zero; the result is not > 0, and
# we use $limit (1) as the stopping point.
#
# if $to is >1, ($limit - $to) will be negative, times $delta of -1
# (negative), giving a positive (>0) value, so we'll set $limit to
# $to.
# The real search loop.
# $i starts at $from (the point we want to start searching from).
# We move through @dbline in the appropriate direction (determined
# by $delta: either -1 (back) or +1 (ahead).
# We stay in as long as we haven't hit an executable line
# ($dbline[$i] == 0 means not executable) and we haven't reached
# the limit yet (test similar to the above).
} ## end if (@_ >= 2)
# If $i points to a line that is executable, return that.
return $i unless $dbline[$i] == 0;
# Format the message and print it: no breakable lines in range.
# If there's a filename in filename_error, we'll see it.
# If not, not.
die "Line$pl $from$upto$filename_error not breakable\n";
} ## end sub breakable_line
=cut
# Capture the file name.
my ($f) = shift;
# Swap the magic line array over there temporarily.
# If there's an error, it's in this other file.
local $filename_error = " of `$f'";
# Find the breakable line.
breakable_line(@_);
# *dbline and $filename_error get restored when this block ends.
} ## end sub breakable_line_in_filename
=cut
sub break_on_line {
my ($i, $cond) = @_;
# Always true if no condition supplied.
my $inii = $i;
my $after = '';
my $pl = '';
# Woops, not a breakable line. $filename_error allows us to say
# if it was in a different file.
# Mark this file as having breakpoints in it.
# If there is an action or condition here already ...
if ($dbline{$i}) {
# ... swap this condition for the existing one.
}
else {
# Nothing here - just add the condition.
}
} ## end sub break_on_line
doesn't work.
=cut
sub cmd_b_line {
eval { break_on_line(@_); 1 } or do {
local $\ = '';
print $OUT $@ and return;
};
} ## end sub cmd_b_line
=cut
sub break_on_filename_line {
my ($f, $i, $cond) = @_;
# Always true if condition left off.
# Switch the magical hash temporarily.
# Localize the variables that break_on_line uses to make its message.
local $filename_error = " of `$f'";
local $filename = $f;
# Add the breakpoint.
break_on_line($i, $cond);
} ## end sub break_on_filename_line
=cut
# Find a breakable line if there is one.
# Always true if missing.
# Add the breakpoint.
break_on_filename_line($f, $i, $cond);
} ## end sub break_on_filename_line_range
=cut
# Returned value from find_sub() is fullpathname:startline-endline.
# The match creates the list (fullpathname, start, end). Falling off
# the end of the subroutine returns this implicitly.
} ## end sub subroutine_filename_lines
=cut
sub break_subroutine {
my $subname = shift;
# Get filename, start, and end.
or die "Subroutine $subname not found.\n";
# Null condition changes to '1' (always true).
# Put a break the first place possible in the range of lines
# that make up this subroutine.
break_on_filename_line_range($file, $s, $e, @_);
} ## end sub break_subroutine
=over 4
=item 1. If it's already fully-qualified, leave it alone.
=item 2. Try putting it in the current package.
=item 3. If it's not there, try putting it in CORE::GLOBAL if it exists there.
=item 4. If it starts with '::', put it in 'main::'.
=back
After all this cleanup, we call C<break_subroutine> to try to set the
breakpoint.
=cut
sub cmd_b_sub {
# Add always-true condition if we have none.
# If the subname isn't a code reference, qualify it so that
# break_subroutine() will work right.
unless (ref $subname eq 'CODE') {
# Not Perl4.
$subname =~ s/\'/::/g;
my $s = $subname;
# Put it in this package unless it's already qualified.
unless $subname =~ /::/;
# Requalify it into CORE::GLOBAL if qualifying it into this
# package resulted in its not being defined, but only do so
# if it really is in CORE::GLOBAL.
$subname = "CORE::GLOBAL::$s"
if not defined &$subname
and $s !~ /::/
and defined &{"CORE::GLOBAL::$s"};
# Put it in package 'main' if it has a leading ::.
} ## end unless (ref $subname eq 'CODE')
# Try to set the breakpoint.
local $\ = '';
print $OUT $@ and return;
}
} ## end sub cmd_b_sub
=cut
sub cmd_B {
my $cmd = shift;
# No line spec? Use dbline.
# If there is one, use it if it's non-zero, or wipe it out if it is.
my $dbline = shift;
# If the line was dot, make the line the current one.
# If it's * we're deleting all the breakpoints.
if ($line eq '*') {
}
# If there is a line spec, delete the breakpoint on that line.
elsif ($line =~ /^(\S.*)/) {
local $\ = '';
print $OUT $@ and return;
};
} ## end elsif ($line =~ /^(\S.*)/)
# No line spec.
else {
print $OUT
"Deleting a breakpoint requires a line number, or '*' for all\n"
; # hint
}
} ## end sub cmd_B
=cut
sub delete_breakpoint {
my $i = shift;
# If we got a line, delete just that one.
if (defined($i)) {
# Woops. This line wasn't breakable at all.
# Kill the condition, but leave any action.
$dbline{$i} =~ s/^[^\0]*//;
# Remove the entry entirely if there's no action left.
}
# No line; delete them all.
else {
print $OUT "Deleting all breakpoints...\n";
# %had_breakpoints lists every file that had at least one
# breakpoint in it.
for my $file (keys %had_breakpoints) {
# Switch to the desired file temporarily.
my $max = $#dbline;
my $was;
# For all lines in this file ...
for ($i = 1 ; $i <= $max ; $i++) {
# If there's a breakpoint or action on this line ...
if (defined $dbline{$i}) {
# ... remove the breakpoint.
$dbline{$i} =~ s/^[^\0]+//;
if ($dbline{$i} =~ s/^\0?$//) {
# Remove the entry altogether if no action is there.
delete $dbline{$i};
}
} ## end if (defined $dbline{$i...
} ## end for ($i = 1 ; $i <= $max...
# If, after we turn off the "there were breakpoints in this file"
# bit, the entry in %had_breakpoints for this file is zero,
# we should remove this file from the hash.
delete $had_breakpoints{$file};
}
} ## end for my $file (keys %had_breakpoints)
# Kill off all the other breakpoints that are waiting for files that
# haven't been loaded yet.
undef %postponed;
undef %postponed_file;
undef %break_on_load;
} ## end else [ if (defined($i))
} ## end sub delete_breakpoint
=cut
$signal = 1;
}
=over 4
=item * Showing all the debugger help
=item * Showing help for a specific command
=back
=cut
sub cmd_h {
my $cmd = shift;
# If we have no operand, assume null.
my $line = shift || '';
# 'h h'. Print the long-format help.
if ($line =~ /^h\s*/) {
print_help($help);
}
# 'h <something>'. Search for the command and print only its help.
elsif ($line =~ /^(\S.*)$/) {
# support long commands; otherwise bogus errors
# happen when you ask for h on <CR> for example
# (for proper error message)
# want to use it as a pattern.
# XXX: finds CR but not <CR>
# Search the help string for the command.
if ($help =~ /^ # Start of a line
<? # Optional '<'
(?:[IB]<) # Optional markup
$qasked # The requested command
/mx) {
# It's there; pull it out and print it.
while ($help =~ /^
(<? # Optional '<'
(?:[IB]<) # Optional markup
$qasked # The command
([\s\S]*?) # Description line(s)
\n) # End of last description line
(?!\s) # Next line not starting with
# whitespace
/mgx) {
print_help($1);
}
}
# Not found; not a debugger command.
else {
print_help("B<$asked> is not a debugger command.\n");
}
} ## end elsif ($line =~ /^(\S.*)$/)
# 'h' - print the summary help.
else {
}
} ## end sub cmd_h
=cut
sub cmd_i {
my $cmd = shift;
my $line = shift;
if ($@) {
} else {
ISA:
no strict 'refs';
print join(', ', map { # snaffled unceremoniously from Class::ISA
"$_".(defined(${"$_\::VERSION"}) ? ' '.${"$_\::VERSION"} : undef)
print "\n";
}
}
} ## end sub cmd_i
=cut
sub cmd_l {
my $current_line = $line;
my $cmd = shift;
my $line = shift;
# If this is '-something', delete any spaces after the dash.
$line =~ s/^-\s*$/-/;
# If the line is '$something', assume this is a scalar containing a
# line number.
if ($line =~ /^(\$.*)/s) {
# Set up for DB::eval() - evaluate in *user* context.
$evalarg = $1;
my ($s) = &eval;
# Ooops. Bad scalar.
# Good scalar. If it's a reference, find what it points to.
$s = CvGV_name($s);
print($OUT "Interpreted as: $1 $s\n");
$line = "$1 $s";
# Call self recursively to really do the command.
&cmd_l('l', $s);
} ## end if ($line =~ /^(\$.*)/s)
# l name. Try to find a sub by that name.
elsif ($line =~ /^([\':A-Za-z_][\':\w]*(\[.*\])?)/s) {
my $s = $subname = $1;
# De-Perl4.
$subname =~ s/\'/::/;
# Put it in this package unless it starts with ::.
# Put it in CORE::GLOBAL if t doesn't start with :: and
# it doesn't live in this package and it lives in CORE::GLOBAL.
$subname = "CORE::GLOBAL::$s"
if not defined &$subname
and $s !~ /::/
and defined &{"CORE::GLOBAL::$s"};
# Put leading '::' names into 'main::'.
# Get name:start-stop from find_sub, and break this up at
# colons.
# Pull off start-stop.
# If the name contained colons, the split broke it up.
# Put it back together.
# If we're not in that file, switch over to it.
print $OUT "Switching to file '$file'.\n"
unless $slave_editor;
# Switch debugger's magic structures.
$max = $#dbline;
} ## end if ($file ne $filename)
# Subrange is 'start-stop'. If this is less than a window full,
# swap it to 'start+', which will list a window from the start point.
if ($subrange) {
$subrange =~ s/-.*/+/;
}
# Call self recursively to list the range.
} ## end if ($subrange)
# Couldn't find it.
else {
print $OUT "Subroutine $subname not found.\n";
}
} ## end elsif ($line =~ /^([\':A-Za-z_][\':\w]*(\[.*\])?)/s)
# Bare 'l' command.
elsif ($line =~ /^\s*$/) {
# Compute new range to list.
# Recurse to do it.
}
# l [start]+number_of_lines
elsif ($line =~ /^(\d*)\+(\d*)$/) {
# Don't reset start for 'l +nnn'.
# Increment for list. Use window size if not specified.
# (Allows 'l +' to work.)
$incr = $2;
# Create a line range we'll understand, and recurse to do it.
} ## end elsif ($line =~ /^(\d*)\+(\d*)$/)
# l start-stop or l start,stop
elsif ($line =~ /^((-?[\d\$\.]+)([-,]([\d\$\.]+))?)?/) {
# Determine end point; use end of file if not specified.
# Go on to the end, and then stop.
# Determine start line.
$i = $2;
$i = $line if $i eq '.';
$i = 1 if $i < 1;
# If we're running under a slave editor, force it to show the lines.
if ($slave_editor) {
print $OUT "\032\032$filename:$i:0\n";
$i = $end;
}
# We're doing it ourselves. We want to show the line and special
# markers for:
# - the current line in execution
# - whether a line is breakable or not
# - whether a line has a break or not
# - whether a line has an action or not
else {
for (; $i <= $end ; $i++) {
# Check for breakpoints and actions.
if $dbline{$i};
# ==> if this is the current line in execution,
# : if it's breakable.
$arrow =
? '==>'
# Add break and action indicators.
# Print the line.
# Move on to the next line. Drop out on an interrupt.
$i++, last if $signal;
} ## end for (; $i <= $end ; $i++)
# Line the prompt up; print a newline if the last line listed
# didn't have a newline.
} ## end else [ if ($slave_editor)
# Save the point we last listed to in case another relative 'l'
# command is desired. Don't let it run off the end.
$start = $i;
} ## end elsif ($line =~ /^((-?[\d\$\.]+)([-,]([\d\$\.]+))?)?/)
} ## end sub cmd_l
=cut
sub cmd_L {
my $cmd = shift;
# If no argument, list everything. Pre-5.8.0 version always lists
# everything
my $arg = shift || 'abw';
# See what is wanted.
# Breaks and actions are found together, so we look in the same place
# for both.
if ($break_wanted or $action_wanted) {
# Look in all the files with breakpoints...
for my $file (keys %had_breakpoints) {
# Temporary switch to this file.
# Set up to look through the whole file.
my $max = $#dbline;
my $was; # Flag: did we print something
# in this file?
# For each line in the file ...
for ($i = 1 ; $i <= $max ; $i++) {
# We've got something on this line.
if (defined $dbline{$i}) {
# Print the header if we haven't.
# Print the line.
# Pull out the condition and the action.
# Print the break if there is one and it's wanted.
if $stop
and $break_wanted;
# Print the action if there is one and it's wanted.
if $action
and $action_wanted;
# Quit if the user hit interrupt.
last if $signal;
} ## end if (defined $dbline{$i...
} ## end for ($i = 1 ; $i <= $max...
} ## end for my $file (keys %had_breakpoints)
} ## end if ($break_wanted or $action_wanted)
# Look for breaks in not-yet-compiled subs:
if (%postponed and $break_wanted) {
print $OUT "Postponed breakpoints in subroutines:\n";
my $subname;
print $OUT " $subname\t$postponed{$subname}\n";
last if $signal;
}
} ## end if (%postponed and $break_wanted)
# Find files that have not-yet-loaded breaks:
my @have = map { # Combined keys
keys %{ $postponed_file{$_} }
} keys %postponed_file;
# If there are any, list them.
print $OUT "Postponed breakpoints in files:\n";
for $file (keys %postponed_file) {
print $OUT " $file:\n";
print $OUT " $line:\n";
if $stop
and $break_wanted;
if $action
and $action_wanted;
last if $signal;
} ## end for $line (sort { $a <=>...
last if $signal;
} ## end for $file (keys %postponed_file)
} ## end if (@have and ($break_wanted...
if (%break_on_load and $break_wanted) {
print $OUT "Breakpoints on load:\n";
my $file;
for $file (keys %break_on_load) {
print $OUT " $file\n";
last if $signal;
}
} ## end if (%break_on_load and...
if ($watch_wanted) {
if ($trace & 2) {
print $OUT " $expr\n";
last if $signal;
}
} ## end if ($trace & 2)
} ## end if ($watch_wanted)
} ## end sub cmd_L
=cut
sub cmd_M {
&list_modules();
}
C<parse_options> for processing.
=cut
sub cmd_o {
my $cmd = shift;
# Nonblank. Try to parse and process.
if ($opt =~ /^(\S.*)/) {
&parse_options($1);
}
# Blank. List the current option settings.
else {
for (@options) {
&dump_option($_);
}
}
} ## end sub cmd_o
=cut
sub cmd_O {
}
=cut
sub cmd_v {
my $cmd = shift;
my $line = shift;
# Extract the line to list around. (Astute readers will have noted that
# this pattern will match whether or not a numeric line is specified,
# which means that we'll always enter this loop (though a non-numeric
# argument results in no action at all)).
if ($line =~ /^(\d*)$/) {
# Total number of lines to list (a windowful).
# Set the start to the argument given (if there was one).
# Back up by the context amount.
# Put together a linespec that cmd_l will like.
# List the lines.
} ## end if ($line =~ /^(\d*)$/)
} ## end sub cmd_v
=cut
sub cmd_w {
my $cmd = shift;
# Null expression if no arguments.
my $expr = shift || '';
# If expression is not null ...
if ($expr =~ /^(\S.*)/) {
# ... save it.
# Parameterize DB::eval and call it to get the expression's value
# in the user's context. This version can handle expressions which
# return a list value.
# Save the current value of the expression.
# We are now watching expressions.
$trace |= 2;
} ## end if ($expr =~ /^(\S.*)/)
# You have to give one to get one.
else {
print $OUT
"Adding a watch-expression requires an expression\n"; # hint
}
} ## end sub cmd_w
=cut
sub cmd_W {
my $cmd = shift;
my $expr = shift || '';
# Delete them all.
if ($expr eq '*') {
# Not watching now.
$trace &= ~2;
print $OUT "Deleting all watch expressions ...\n";
# And all gone.
}
# Delete one of them.
elsif ($expr =~ /^(\S.*)/) {
# Where we are in the list.
my $i_cnt = 0;
# For each expression ...
foreach (@to_watch) {
# Does this one match the command argument?
# Yes. Turn it off, and its value too.
}
$i_cnt++;
} ## end foreach (@to_watch)
# We don't bother to turn watching off because
# a) we don't want to stop calling watchfunction() it it exists
# b) foreach over a null list doesn't do anything anyway
} ## end elsif ($expr =~ /^(\S.*)/)
# No command arguments entered.
else {
print $OUT
"Deleting a watch-expression requires an expression, or '*' for all\n"
; # hint
}
} ## end sub cmd_W
### END of the API section
=head1 SUPPORT ROUTINES
These are general support routines that are used in a number of places
throughout the debugger.
=head2 save
save() saves the user's versions of globals that would mess us up in C<@saved>,
and installs the versions we like better.
=cut
sub save {
# Save eval failure, command failure, extended OS error, output field
# separator, input record separator, output record separator and
# the warning setting.
@saved = ($@, $!, $^E, $,, $/, $\, $^W);
$, = ""; # output field separator is null string
$/ = "\n"; # input record separator is newline
$\ = ""; # output record separator is null string
$^W = 0; # warnings are off
} ## end sub save
=head2 C<print_lineinfo> - show where we are now
print_lineinfo prints whatever it is that it is handed; it prints it to the
C<$LINEINFO> filehandle instead of just printing it to STDOUT. This allows
us to feed line information to a slave editor without messing up the
debugger output.
=cut
sub print_lineinfo {
# Make the terminal sensible if we're not the primary debugger.
local $\ = '';
local $, = '';
print $LINEINFO @_;
} ## end sub print_lineinfo
=head2 C<postponed_sub>
Handles setting postponed breakpoints in subroutines once they're compiled.
For breakpoints, we use C<DB::find_sub> to locate the source file and line
range for the subroutine, then mark the file as having a breakpoint,
temporarily switch the C<*dbline> glob over to the source file, and then
search the given range of lines to find a breakable line. If we find one,
we set the breakpoint on it, deleting the breakpoint from C<%postponed>.
=cut
# The following takes its argument via $evalarg to preserve current @_
sub postponed_sub {
# Get the subroutine name.
my $subname = shift;
# If this is a 'break +<n> if <condition>' ...
# If there's no offset, use '+0'.
# find_sub's value is 'fullpath-filename:start-stop'. It's
# possible that the filename might have colons in it too.
if ($i) {
# We got the start line. Add the offset '+<n>' from
# $postponed{subname}.
$i += $offset;
# Switch to the file this sub is in, temporarily.
# No warnings, please.
local $^W = 0; # != 0 is magical below
# This file's got a breakpoint in it.
# Last line in file.
my $max = $#dbline;
# Search forward until we hit a breakable line or get to
# the end of the file.
# Copy the breakpoint in and delete it from %postponed.
} ## end if ($i)
# find_sub didn't find the sub.
else {
local $\ = '';
print $OUT "Subroutine $subname not found.\n";
}
return;
} ## end if ($postponed{$subname...
#print $OUT "In postponed_sub for `$subname'.\n";
} ## end sub postponed_sub
=head2 C<postponed>
Called after each required file is compiled, but before it is executed;
also called if the name of a just-compiled subroutine is a key of
C<%postponed>. Propagates saved breakpoints (from C<b compile>, C<b load>,
etc.) into the just-compiled code.
If this is a C<require>'d file, the incoming parameter is the glob
C<*{"_<$filename"}>, with C<$filename> the name of the C<require>'d file.
If it's a subroutine, the incoming parameter is the subroutine name.
=cut
sub postponed {
# If there's a break, process it.
if ($ImmediateStop) {
# Right, we've stopped. Turn it off.
$ImmediateStop = 0;
# Enter the command loop when DB::DB gets called.
$signal = 1;
}
# If this is a subroutine, let postponed_sub() deal with it.
# Not a subroutine. Deal with the file.
local *dbline = shift;
$filename =~ s/^_<//;
local $\ = '';
if $break_on_load{$filename};
# Do we have any breakpoints to put in this file?
return unless $postponed_file{$filename};
# Yes. Mark this file as having breakpoints.
# "Cannot be done: unsufficient magic" - we can't just put the
# breakpoints saved in %postponed_file into %dbline by assigning
# the whole hash; we have to do it one item at a time for the
# breakpoints to be set properly.
#%dbline = %{$postponed_file{$filename}};
# Set the breakpoints, one at a time.
my $key;
# Stash the saved breakpoint into the current file's magic line array.
}
# This file's been compiled; discard the stored breakpoints.
delete $postponed_file{$filename};
} ## end sub postponed
=head2 C<dumpit>
C<dumpit> is the debugger's wrapper around dumpvar.pl.
It gets a filehandle (to which C<dumpvar.pl>'s output will be directed) and
a reference to a variable (the thing to be dumped) as its input.
The incoming filehandle is selected for output (C<dumpvar.pl> is printing to
the currently-selected filehandle, thank you very much). The current
values of the package globals C<$single> and C<$trace> are backed up in
lexicals, and they are turned off (this keeps the debugger from trying
to single-step through C<dumpvar.pl> (I think.)). C<$frame> is localized to
messages from printing, and C<$doret> is localized as well and set to -2 to
prevent return values from being shown.
C<dumpit()> then checks to see if it needs to load C<dumpvar.pl> and
tries to load it (note: if you have a C<dumpvar.pl> ahead of the
installed version in @INC, yours will be used instead. Possible security
problem?).
It then checks to see if the subroutine C<main::dumpValue> is now defined
(it should have been defined by C<dumpvar.pl>). If it has, C<dumpit()>
localizes the globals necessary for things to be sane when C<main::dumpValue()>
is called, and picks up the variable to be dumped from the parameter list.
It checks the package global C<%options> to see if there's a C<dumpDepth>
specified. If not, -1 is assumed; if so, the supplied value gets passed on to
C<dumpvar.pl>. This tells C<dumpvar.pl> where to leave off when dumping a
structure: -1 means dump everything.
C<dumpValue()> is then called if possible; if not, C<dumpit()>just prints a
warning.
In either case, C<$single>, C<$trace>, C<$frame>, and C<$doret> are restored
and we then return to the caller.
=cut
sub dumpit {
# Save the current output filehandle and switch to the one
# passed in as the first parameter.
local ($savout) = select(shift);
# Save current settings of $single and $trace, and then turn them off.
# XXX Okay, what do $frame and $doret do, again?
local $frame = 0;
local $doret = -2;
# Load dumpvar.pl unless we've already got the sub we need from it.
do 'dumpvar.pl';
}
# If the load succeeded (or we already had dumpvalue()), go ahead
# and dump things.
local $\ = '';
local $, = '';
local $" = ' ';
my $v = shift;
} ## end if (defined &main::dumpValue)
# Oops, couldn't load dumpvar.pl.
else {
local $\ = '';
print $OUT "dumpvar.pl not available.\n";
}
# Reset $single and $trace to their old values.
# Restore the old filehandle.
select($savout);
} ## end sub dumpit
=head2 C<print_trace>
C<print_trace>'s job is to print a stack trace. It does this via the
C<dump_trace> routine, which actually does all the ferreting-out of the
stack trace data. C<print_trace> takes care of formatting it nicely and
printing it to the proper filehandle.
Parameters:
=over 4
=item * The filehandle to print to.
=item * How many frames to skip before starting trace.
=item * How many frames to print.
=item * A flag: if true, print a "short" trace without filenames, line numbers, or arguments
=back
The original comment below seems to be noting that the traceback may not be
correct if this routine is called in a tied method.
=cut
# Tied method do not create a context, so may get wrong message:
sub print_trace {
local $\ = '';
my $fh = shift;
# If this is going to a slave editor, but we're not the primary
# debugger, reset it first.
resetterm(1)
and $term_pid != $$; # not the primary
# Collect the actual trace information to be formatted.
# This is an array of hashes of subroutine call info.
# Grab the "short report" flag from @_.
# Run through the traceback info, format it, and print it.
my $s;
for ($i = 0 ; $i <= $#sub ; $i++) {
# Drop out if the user has lost interest and hit control-C.
last if $signal;
# Set the separator so arrys print nice.
local $" = ', ';
# Grab and stringify the arguments if they are there.
my $args =
? "(@{ $sub[$i]{args} })"
: '';
# Shorten them up if $maxtrace says they're too long.
# Get the file name.
# Put in a filename header if short is off.
# Get the actual sub's name, and shorten to $maxtrace's requirement.
$s = $sub[$i]{sub};
# Short report uses trimmed file and sub names.
if ($short) {
print $fh
"$sub[$i]{context}=$sub$args from $file:$sub[$i]{line}\n";
} ## end if ($short)
# Non-short report includes full names.
else {
" line $sub[$i]{line}\n";
}
} ## end for ($i = 0 ; $i <= $#sub...
} ## end sub print_trace
=head2 dump_trace(skip[,count])
Actually collect the traceback information available via C<caller()>. It does
some filtering and cleanup of the data, but mostly it just collects it to
make C<print_trace()>'s job easier.
C<skip> defines the number of stack frames to be skipped, working backwards
from the most current. C<count> determines the total number of frames to
be returned; all of them (well, the first 10^9) are returned if C<count>
is omitted.
This routine returns a list of hashes, from most-recent to least-recent
stack frame. Each has the following keys and values:
=over 4
=item * C<context> - C<.> (null), C<$> (scalar), or C<@> (array)
=item * C<sub> - subroutine name, or C<eval> information
=item * C<args> - undef, or a reference to an array of arguments
=item * C<file> - the file in which this item was defined (if any)
=item * C<line> - the line on which it was defined
=back
=cut
sub dump_trace {
# How many levels to skip.
my $skip = shift;
# How many levels to show. (1e9 is a cheap way of saying "all of them";
# it's unlikely that we'll have more than a billion stack frames. If you
# do, you've got an awfully big machine...)
my $count = shift || 1e9;
# We increment skip because caller(1) is the first level *back* from
# the current one. Add $skip to the count of frames so we have a
# simple stop criterion, counting from $skip to $count+$skip.
$skip++;
# These variables are used to capture output from caller();
# XXX Okay... why'd we do that?
local $frame = 0;
# Do not want to trace this.
$trace = 0;
# Start out at the skip count.
# If we haven't reached the number of frames requested, and caller() is
# still returning something, stay in the loop. (If we pass the requested
# number of stack frames, or we run out - caller() returns nothing - we
# quit.
# Up the stack frame index to go back one more level each time.
for (
$i = $skip ;
$i < $count
$i++
)
{
# Go through the arguments and save them for later.
@a = ();
my $type;
if (not defined $arg) { # undefined parameter
push @a, "undef";
}
push @a, "tied";
}
push @a, "ref($type)";
}
else { # can be stringified
local $_ =
"$arg"; # Safe to stringify now - should not call f().
# Backslash any single-quotes or backslashes.
s/([\'\\])/\\$1/g;
# Single-quote it unless it's a number or a colon-separated
# name.
s/(.*)/'$1'/s
unless /^(?: -?[\d.]+ | \*[\w:]* )$/x;
# Turn high-bit characters into meta-whatever.
# Turn control characters into ^-whatever.
push (@a, $_);
} ## end else [ if (not defined $arg)
} ## end for $arg (@args)
# If context is true, this is array (@)context.
# If context is false, this is scalar ($) context.
# If neither, context isn't defined. (This is apparently a 'can't
# happen' trap.)
# if the sub has args ($h true), make an anonymous array of the
# dumped args.
$args = $h ? [@a] : undef;
# remove trailing newline-whitespace-semicolon-end of line sequence
# from the eval text, if any.
$e =~ s/\n\s*\;\s*\Z// if $e;
# Escape backslashed single-quotes again if necessary.
$e =~ s/([\\\'])/\\$1/g if $e;
# if the require flag is true, the eval text is from a require.
if ($r) {
$sub = "require '$e'";
}
# if it's false, the eval text is really from an eval.
elsif (defined $r) {
$sub = "eval '$e'";
}
# If the sub is '(eval)', this is a block eval, meaning we don't
# know what the eval'ed text actually was.
elsif ($sub eq '(eval)') {
$sub = "eval {...}";
}
# Stick the collected information into @sub as an anonymous hash.
push (
@sub,
{
sub => $sub,
}
);
# Stop processing frames if the user hit control-C.
last if $signal;
} ## end for ($i = $skip ; $i < ...
# Restore the trace value again.
@sub;
} ## end sub dump_trace
=head2 C<action()>
C<action()> takes input provided as the argument to an add-action command,
either pre- or post-, and makes sure it's a complete command. It doesn't do
any fancy parsing; it just keeps reading input until it gets a string
without a trailing backslash.
=cut
sub action {
my $action = shift;
while ($action =~ s/\\$//) {
# We have a backslash on the end. Read more.
} ## end while ($action =~ s/\\$//)
# Return the assembled action.
$action;
} ## end sub action
=head2 unbalanced
This routine mostly just packages up a regular expression to be used
to check that the thing it's being matched against has properly-matched
curly braces.
Of note is the definition of the $balanced_brace_re global via ||=, which
speeds things up by only creating the qr//'ed expression once; if it's
already defined, we don't try to define it again. A speed hack.
=cut
sub unbalanced {
# I hate using globals!
$balanced_brace_re ||= qr{
^ \{
(?:
(?> [^{}] + ) # Non-parens without backtracking
|
(??{ $balanced_brace_re }) # Group with matching parens
) *
\} $
}x;
return $_[0] !~ m/$balanced_brace_re/;
} ## end sub unbalanced
=head2 C<gets()>
C<gets()> is a primitive (very primitive) routine to read continuations.
It was devised for reading continuations for actions.
it just reads more input with X<C<readline()>> and returns it.
=cut
sub gets {
&readline("cont: ");
}
=head2 C<DB::system()> - handle calls to<system()> without messing up the debugger
The C<system()> function assumes that it can just go ahead and use STDIN and
STDOUT, but under the debugger, we want it to use the debugger's input and
outout filehandles.
C<DB::system()> socks away the program's STDIN and STDOUT, and then substitutes
the debugger's IN and OUT filehandles for them. It does the C<system()> call,
and then puts everything back again.
=cut
sub system {
# We save, change, then restore STDIN and STDOUT to avoid fork() since
# some non-Unix systems can do system() but have problems with fork().
# XXX: using csh or tcsh destroys sigint retvals!
system(@_);
close(SAVEIN);
close(SAVEOUT);
# most of the $? crud was coping with broken cshisms
if ($? >> 8) {
}
elsif ($?) {
&warn(
"(Command died of SIG#",
($? & 127),
(($? & 128) ? " -- core dumped" : ""),
")", "\n"
);
} ## end elsif ($?)
return $?;
} ## end sub system
=head1 TTY MANAGEMENT
The subs here do some of the terminal management for multiple debuggers.
=head2 setterm
Top-level function called when we want to set up a new terminal for use
by the debugger.
If the C<noTTY> debugger option was set, we'll either use the terminal
supplied (the value of the C<noTTY> option), or we'll use C<Term::Rendezvous>
to find one. If we're a forked debugger, we call C<resetterm> to try to
get a whole new terminal if we can.
In either case, we set up the terminal next. If the C<ReadLine> option was
true, we'll get a C<Term::ReadLine> object for the current terminal and save
the appropriate attributes. We then
=cut
sub setterm {
# Load Term::Readline, but quietly; don't debug it and don't trace it.
local $frame = 0;
local $doret = -2;
# If noTTY is set, but we have a TTY name, go ahead and hook up to it.
if ($notty) {
if ($tty) {
my ($i, $o) = split $tty, /,/;
$o = $i unless defined $o;
$| = 1;
select($sel);
} ## end if ($tty)
# We don't have a TTY - try to find one via Term::Rendezvous.
else {
eval "require Term::Rendezvous;" or die;
# See if we have anything to pass to Term::Rendezvous.
# Rendezvous and get the filehandles.
} ## end else [ if ($tty)
} ## end if ($notty)
# We're a daughter debugger. Try to fork off another TTY.
resetterm(2);
}
# If we shouldn't use Term::ReadLine, don't.
if (!$rl) {
}
# We're using Term::ReadLine. Get all the attributes for this terminal.
else {
if defined $rl_attribs->{basic_word_break_characters}
} ## end else [ if (!$rl)
# Set up the LINEINFO filehandle.
}
# XXX Ornaments are turned on unconditionally, which is not
# always a good thing.
$term_pid = $$;
} ## end sub setterm
=head1 GET_FORK_TTY EXAMPLE FUNCTIONS
When the process being debugged forks, or the process invokes a command
via C<system()> which starts a new debugger, we need to be able to get a new
C<IN> and C<OUT> filehandle for the new debugger. Otherwise, the two processes
fight over the terminal, and you can never quite be sure who's going to get the
input you're typing.
C<get_fork_TTY> is a glob-aliased function which calls the real function that
is tasked with doing all the necessary operating system mojo to get a new
TTY (and probably another window) and to direct the new debugger to read and
write there.
The debugger provides C<get_fork_TTY> functions which work for X Windows and
OS/2. Other systems are not supported. You are encouraged to write
C<get_fork_TTY> functions which work for I<your> platform and contribute them.
=head3 C<xterm_get_fork_TTY>
This function provides the C<get_fork_TTY> function for X windows. If a
program running under the debugger forks, a new <xterm> window is opened and
the subsidiary debugger is directed there.
The C<open()> call is of particular note here. We have the new C<xterm>
we're spawning route file number 3 to STDOUT, and then execute the C<tty>
command (which prints the device name of the TTY we'll want to use for input
and output to STDOUT, then C<sleep> for a very long time, routing this output
to file number 3. This way we can simply read from the <XT> filehandle (which
is STDOUT from the I<commands> we ran) to get the TTY we want to use.
Only works if C<xterm> is in your path and C<$ENV{DISPLAY}>, etc. are
properly set up.
=cut
sub xterm_get_fork_TTY {
(my $name = $0) =~ s,^.*[/\\],,s;
open XT,
sleep 10000000' |];
# Get the output from 'tty' and clean it up a little.
chomp $tty;
# There's our new TTY.
return $tty;
} ## end sub xterm_get_fork_TTY
=cut
# This example function resets $IN, $OUT itself
sub os2_get_fork_TTY {
local $^F = 40; # XXXX Fixme!
local $\ = '';
# Having -d in PERL5OPT would lead to a disaster...
(my $name = $0) =~ s,^.*[/\\],,s;
my @args;
if (
# system P_SESSION will fail if there is another process
# in the same session with a "dependent" asynchronous child session.
and @args = (
"Daughter Perl debugger $pids $name"
)
and (
END {sleep 5 unless $loaded}
set_title pop;
my $out = shift;
select OUT; $| = 1;
or warn "system P_SESSION: $!, $^E" and 0
)
and close $in1
and close $out2
)
{
$tty = '*reset*';
return ''; # Indicate that reset_IN_OUT is called
} ## end if (pipe $in1, $out1 and...
return;
} ## end sub os2_get_fork_TTY
=head2 C<create_IN_OUT($flags)>
Create a new pair of filehandles, pointing to a new TTY. If impossible,
try to diagnose why.
Flags are:
=over 4
=item * 1 - Don't know how to create a new TTY.
=item * 2 - Debugger has forked, but we can't get a new TTY.
=item * 4 - standard debugger startup is happening.
=back
=cut
# If we know how to get a new TTY, do it! $in will have
# the TTY name if get_fork_TTY works.
# It used to be that
if (not defined $in) {
my $why = shift;
# We don't know how.
I<#########> Forked, but do not know how to create a new B<TTY>. I<#########>
# Forked debugger.
I<#########> Daughter session, do not know how to change a B<TTY>. I<#########>
# Note that both debuggers are fighting over the same input.
print_help(<<EOP);
} ## end if (not defined $in)
elsif ($in ne '') {
}
else {
}
undef $fork_TTY;
} ## end sub create_IN_OUT
=head2 C<resetterm>
Handles rejiggering the prompt when we've forked off a new debugger.
If the new debugger happened because of a C<system()> that invoked a
program under the debugger, the arrow between the old pid and the new
in the prompt has I<two> dashes instead of one.
We take the current list of pids and add this one to the end. If there
isn't any list yet, we make one up out of the initial pid associated with
the terminal and our new pid, sticking an arrow (either one-dashed or
two dashed) in between them.
If C<CreateTTY> is off, or C<resetterm> was called with no arguments,
we don't try to create a new IN and OUT filehandle. Otherwise, we go ahead
and try to do that.
=cut
# Needs to be passed to create_IN_OUT() as well.
my $in = shift;
# resetterm(2): got in here because of a system() starting a debugger.
# resetterm(1): just forked.
# If there's already a list of pids, add this to the end.
if ($pids) {
}
# No pid list. Time to make one.
else {
$pids = "[$term_pid->$$]";
}
# The prompt we're going to be using for this debugger.
# We now 0wnz this terminal.
$term_pid = $$;
# Just return if we're not supposed to try to create a new TTY.
create_IN_OUT($in);
} ## end sub resetterm
=head2 C<readline>
First, we handle stuff in the typeahead buffer. If there is any, we shift off
the next line, print a message saying we got it, add it to the terminal
history (if possible), and return it.
If there's nothing in the typeahead buffer, check the command filehandle stack.
If there are any filehandles there, read from the last one, and return the line
if we got one. If not, we pop the filehandle off and close it, and try the
next one up the stack.
If we've emptied the filehandle stack, we check to see if we've got a socket
open, and we read that and return it if we do. If we don't, we just call the
core C<readline()> and return its value.
=cut
sub readline {
# Localize to prevent it from being smashed in the program being debugged.
local $.;
# Pull a line out of the typeahead if there's stuff there.
if (@typeahead) {
# How many lines left.
# Get the next line.
# Print a message saying we got input from the typeahead.
local $\ = '';
# Add it to the terminal history (if possible).
if length($got) > 1
return $got;
} ## end if (@typeahead)
# return value printing.
local $frame = 0;
local $doret = -2;
# If there are stacked filehandles to read from ...
while (@cmdfhs) {
# Read from the last one in the stack.
# If we got a line ...
defined $line
: close pop @cmdfhs; # Pop and close
} ## end while (@cmdfhs)
# Nothing on the filehandle stack. Socket?
# Send anyting we have to send.
$OUT->write(join ('', @_));
# Receive anything there is to receive.
my $stuff;
# XXX Don't know. You tell me.
# What we got.
$stuff;
} ## end if (ref $OUT and UNIVERSAL::isa...
# No socket. Just read from the terminal.
else {
$term->readline(@_);
}
} ## end sub readline
=head1 OPTIONS SUPPORT ROUTINES
These routines handle listing and setting option values.
=head2 C<dump_option> - list the current value of an option setting
This routine uses C<option_val> to look up the value for an option.
It cleans up escaped single-quotes and then displays the option and
its value.
=cut
sub dump_option {
$val =~ s/([\\\'])/\\$1/g;
} ## end sub dump_option
=head2 C<option_val> - find the current value of an option
This can't just be a simple hash lookup because of the indirect way that
the option values are stored. Some are retrieved by calling a subroutine,
some are just variables.
You must supply a default value to be used in case the option isn't set.
=cut
sub option_val {
my $val;
# Does this option exist, and is it a variable?
# If so, retrieve the value via the value in %optionVars.
if ( defined $optionVars{$opt}
and defined ${ $optionVars{$opt} }) {
}
# Does this option exist, and it's a subroutine?
# If so, call the subroutine via the ref in %optionAction
# and capture the value.
elsif ( defined $optionAction{$opt}
and defined &{ $optionAction{$opt} }) {
}
# If there's an action or variable for the supplied option,
# but no value was set, use the default.
{
}
# Otherwise, do the simple hash lookup.
else {
}
# If the value isn't defined, use the default.
# Then return whatever the value is.
$val;
} ## end sub option_val
=head2 C<parse_options>
Handles the parsing and execution of option setting/displaying commands.
An option entered by itself is assumed to be 'set me to 1' (the default value)
if the option is a boolean one. If not, the user is prompted to enter a valid
value or to query the current value (via 'option? ').
If 'option=value' is entered, we try to extract a quoted string from the
value (if it is quoted). If it's not, we just use the whole value as-is.
We load any modules required to service this option, and then we set it: if
it just gets stuck in a variable, we do that; if there's a subroutine to
handle setting the option, we call that.
Finally, if we're running in interactive mode, we display the effect of the
user's command back to the terminal, skipping this if we're setting things
during initialization.
=cut
sub parse_options {
local ($_) = @_;
local $\ = '';
# These options need a value. Don't allow them to be clobbered by accident.
my %opt_needs_val = map { ($_ => 1) } qw{
};
while (length) {
my $val_defaulted;
# Clean off excess leading whitespace.
s/^\s+// && next;
# Options are always all word characters, followed by a non-word
# separator.
s/^(\w+)(\W?)// or print($OUT "Invalid option `$_'\n"), last;
# Make sure that such an option exists.
my $val;
# '?' as separator means query, but must have whitespace after it.
if ("?" eq $sep) {
print($OUT "Option query `$opt?' followed by non-space `$_'\n"),
last
if /^\S/;
#&dump_option($opt);
} ## end if ("?" eq $sep)
# Separator is whitespace (or just a carriage return).
# They're going for a default, which we assume is 1.
elsif ($sep !~ /\S/) {
$val_defaulted = 1;
}
# Separator is =. Trying to set a value.
elsif ($sep eq "=") {
# If quoted, extract a quoted string.
if (s/ (["']) ( (?: \\. | (?! \1 ) [^\\] )* ) \1 //x) {
my $quote = $1;
}
# Not quoted. Use the whole thing. Warn about 'option='.
else {
s/^(\S*)//;
$val = $1;
unless length $val;
} ## end else [ if (s/ (["']) ( (?: \\. | (?! \1 ) [^\\] )* ) \1 //x)
} ## end elsif ($sep eq "=")
# "Quoted" with [], <>, or {}.
else { #{ to "let some poor schmuck bounce on the % key in B<vi>."
or print($OUT "Unclosed option value `$opt$sep$_'\n"), last;
} ## end else [ if ("?" eq $sep)
# Exclude non-booleans from getting set to 1 by default.
print $OUT
"Option `$opt' is non-boolean. Use `$cmd $option=VAL' to set, `$cmd $option?' to query\n";
next;
} ## end if ($opt_needs_val{$option...
# Save the option value.
# Load any module that this option requires.
eval qq{
local \$frame = 0;
local \$doret = -2;
require '$optionRequire{$option}';
1;
} || die # XXX: shouldn't happen
if defined $optionRequire{$option} &&
defined $val;
# Set it.
# Stick it in the proper variable if it goes in a variable.
if defined $optionVars{$option} &&
defined $val;
# Call the appropriate sub if it gets set via sub.
if defined $optionAction{$option} &&
defined &{ $optionAction{$option} } &&
defined $val;
# Not initialization - echo the value we set it to.
} ## end while (length)
} ## end sub parse_options
=head1 RESTART SUPPORT
These routines are used to store (and restore) lists of items in environment
variables during a restart.
=head2 set_list
Set_list packages up items to be stored in a set of environment variables
(VAR_n, containing the number of items, and VAR_0, VAR_1, etc., containing
the values). Values outside the standard ASCII charset are stored by encoding
then as hexadecimal values.
=cut
sub set_list {
my $val;
# VAR_n: how many we have. Scalar assignment gets the number of items.
# Grab each item in the list, escape the backslashes, encode the non-ASCII
# as hex, and then save in the appropriate VAR_0, VAR_1, etc.
for $i (0 .. $#list) {
$val =~ s/\\/\\\\/g;
} ## end for $i (0 .. $#list)
} ## end sub set_list
=head2 get_list
Reverse the set_list operation: grab VAR_n to see how many we should be getting
back, and then pull VAR_0, VAR_1. etc. back out.
=cut
sub get_list {
my $stem = shift;
my @list;
my $n = delete $ENV{"${stem}_n"};
my $val;
for $i (0 .. $n - 1) {
}
@list;
} ## end sub get_list
=head1 MISCELLANEOUS SIGNAL AND I/O MANAGEMENT
=head2 catch()
The C<catch()> subroutine is the essence of fast and low-impact. We simply
set an already-existing global scalar variable to a constant value. This
avoids allocating any memory possibly in the middle of something that will
get all confused if we do.
=cut
sub catch {
$signal = 1;
}
=head2 C<warn()>
C<warn> emits a warning, by joining together its arguments and printing
them, with couple of fillips.
If the composited message I<doesn't> end with a newline, we automatically
add C<$!> and a newline to the end of the message. The subroutine expects $OUT
to be set to the filehandle to be used to output warnings; it makes no
assumptions about what filehandles are available.
=cut
sub warn {
my ($msg) = join ("", @_);
local $\ = '';
} ## end sub warn
=head1 INITIALIZATION TTY SUPPORT
=head2 C<reset_IN_OUT>
This routine handles restoring the debugger's input and output filehandles
after we've tried and failed to move them elsewhere. In addition, it assigns
the debugger's output filehandle to $LINEINFO if it was already open there.
=cut
sub reset_IN_OUT {
# If there's a term and it's able to get a new tty, try to get one.
}
# This term can't get a new tty now. Better luck later.
elsif ($term) {
}
# Set the filehndles up as they were.
else {
}
# Unbuffer the output filehandle.
my $o = select $OUT;
$| = 1;
select $o;
# Point LINEINFO to the same output filehandle if it was there before.
} ## end sub reset_IN_OUT
=head1 OPTION SUPPORT ROUTINES
The following routines are used to process some of the more complicated
debugger options.
=head2 C<TTY>
Sets the input and output filehandles to the specified files or pipes.
If the terminal supports switching, we go ahead and do it. If not, and
there's already a terminal in place, we save the information to take effect
on restart.
If there's no terminal yet (for instance, during debugger initialization),
we go ahead and set C<$console> and C<$tty> to the file indicated.
=cut
sub TTY {
# This terminal supports switching to a new TTY.
# Can be a list of two files, or on string containing both names,
# comma-separated.
# XXX Should this perhaps be an assignment from @_?
if ($in =~ /,/) {
# Split list apart if supplied.
}
else {
# Use the same file for both input and output.
}
# Open file onto the debugger's filehandles, if you can.
# Swap to the new filehandles.
# Save the setting for later.
} ## end if (@_ and $term and $term...
# Terminal doesn't support new TTY, or doesn't support readline.
# Can't do it now, try restarting.
# Useful if done through PERLDB_OPTS:
# Return whatever the TTY is.
} ## end sub TTY
=head2 C<noTTY>
Sets the C<$notty> global, controlling whether or not the debugger tries to
get a terminal to read from. If called after a terminal is already in place,
we save the value to use it if we're restarted.
=cut
sub noTTY {
if ($term) {
&warn("Too late to set noTTY, enabled on next `R'!\n") if @_;
}
$notty = shift if @_;
$notty;
} ## end sub noTTY
=head2 C<ReadLine>
Sets the C<$rl> option variable. If 0, we use C<Term::ReadLine::Stub>
(essentially, no C<readline> processing on this "terminal"). Otherwise, we
use C<Term::ReadLine>. Can't be changed after a terminal's in place; we save
the value in case a restart is done so we can change it then.
=cut
sub ReadLine {
if ($term) {
&warn("Too late to set ReadLine, enabled on next `R'!\n") if @_;
}
$rl = shift if @_;
$rl;
} ## end sub ReadLine
=head2 C<RemotePort>
Sets the port that the debugger will try to connect to when starting up.
If the terminal's already been set up, we can't do it, but we remember the
setting in case the user does a restart.
=cut
sub RemotePort {
if ($term) {
&warn("Too late to set RemotePort, enabled on next 'R'!\n") if @_;
}
$remoteport = shift if @_;
} ## end sub RemotePort
=head2 C<tkRunning>
Checks with the terminal to see if C<Tk> is running, and returns true or
false. Returns false if the current terminal doesn't support C<readline>.
=cut
sub tkRunning {
}
else {
local $\ = '';
print $OUT "tkRunning not supported by current ReadLine package.\n";
0;
}
} ## end sub tkRunning
=head2 C<NonStop>
Sets nonstop mode. If a terminal's already been set up, it's too late; the
debugger remembers the setting in case you restart, though.
=cut
sub NonStop {
if ($term) {
&warn("Too late to set up NonStop mode, enabled on next `R'!\n")
if @_;
}
$runnonstop = shift if @_;
} ## end sub NonStop
=head2 C<pager>
Set up the C<$pager> variable. Adds a pipe to the front unless there's one
there already.
=cut
sub pager {
if (@_) {
$pager = shift;
}
$pager;
} ## end sub pager
=head2 C<shellBang>
Sets the shell escape command, and generates a printable copy to be used
in the help.
=cut
sub shellBang {
# If we got an argument, meta-quote it, and add '\b' if it
# ends in a word character.
if (@_) {
$sh = quotemeta shift;
}
# Generate the printable version for the help:
$psh =~ s/\\b$//; # Take off trailing \b if any
$psh; # return the printable version
} ## end sub shellBang
=head2 C<ornaments>
If the terminal has its own ornaments, fetch them. Otherwise accept whatever
was passed as the argument. (This means you can't override the terminal's
ornaments.)
=cut
sub ornaments {
if (defined $term) {
# We don't want to show warning backtraces, but we do want die() ones.
# No ornaments if the terminal doesn't support them.
}
# Use what was passed in if we can't determine it ourselves.
else {
$ornaments = shift;
}
} ## end sub ornaments
=head2 C<recallCommand>
Sets the recall command, and builds a printable version which will appear in
the help text.
=cut
sub recallCommand {
# If there is input, metaquote it. Add '\b' if it ends with a word
# character.
if (@_) {
$rc = quotemeta shift;
}
# Build it into a printable version.
$prc =~ s/\\b$//; # Remove trailing \b
$prc; # Return the printable version
} ## end sub recallCommand
=head2 C<LineInfo> - where the line number information goes
Called with no arguments, returns the file or pipe that line info should go to.
Called with an argument (a file or a pipe), it opens that onto the
C<LINEINFO> filehandle, unbuffers the filehandle, and then returns the
file or pipe again to the caller.
=cut
sub LineInfo {
return $lineinfo unless @_;
$lineinfo = shift;
# If this is a valid "thing to be opened for output", tack a
# '>' onto the front.
# If this is a pipe, the stream points to a slave editor.
$slave_editor = ($stream =~ /^\|/);
# Open it up and unbuffer it.
$| = 1;
select($save);
# Hand the file or pipe back again.
$lineinfo;
} ## end sub LineInfo
=head1 COMMAND SUPPORT ROUTINES
These subroutines provide functionality for various commands.
=head2 C<list_modules>
For the C<M> command: list modules loaded and their versions.
Essentially just runs through the keys in %INC, picks up the
$VERSION package globals from each package, gets the file name, and formats the
information for output.
=cut
my %version;
my $file;
# keys are the "as-loaded" name, values are the fully-qualified path
# to the file itself.
for (keys %INC) {
$file = $_; # get the module name
s,\.p[lm]$,,i; # remove '.pl' or '.pm'
s,/,::,g; # change '/' to '::'
# moves to package DB
# If the package has a $VERSION package global (as all good packages
# should!) decode it and save as partial message.
if (defined ${ $_ . '::VERSION' }) {
}
# Finish up the message with the file the package came from.
} ## end for (keys %INC)
# Hey, dumpit() formats a hash nicely, so why not use it?
} ## end sub list_modules
=head2 C<sethelp()>
Sets up the monster string used to format and print the help.
=head3 HELP MESSAGE FORMAT
The help message is a peculiar format unto itself; it mixes C<pod> 'ornaments'
(BE<lt>E<gt>, IE<gt>E<lt>) with tabs to come up with a format that's fairly
easy to parse and portable, but which still allows the help to be a little
nicer than just plain text.
Essentially, you define the command name (usually marked up with BE<gt>E<lt>
and IE<gt>E<lt>), followed by a tab, and then the descriptive text, ending in a newline. The descriptive text can also be marked up in the same way. If you
need to continue the descriptive text to another line, start that line with
just tabs and then enter the marked-up text.
If you are modifying the help text, I<be careful>. The help-string parser is
not very sophisticated, and if you don't follow these rules it will mangle the
help beyond hope until you fix the string.
=cut
sub sethelp {
# XXX: make sure there are tabs between the command and explanation,
# or print_help will screw up your formatting if you have
# eeevil ornaments enabled. This is an insane mess.
$help = "
. (
? ""
: "
)
. "
`B<R>' after you set them).
Type `|h h' for a paged display if this was too hard to read.
"; # Fix balance of vi % matching: }}}}
# note: tabs in the following section are not-so-helpful
$summary = <<"END_SUM";
B<<>[B<<>]|B<{>[B<{>]|B<>>[B<>>] [I<cmd>] Do pre/post-prompt B<b> [I<ln>|I<event>|I<sub>] [I<cnd>] Set breakpoint
# ')}}; # Fix balance of vi % matching
# and this is really numb...
$pre580_help = "
. (
? ""
: "
) .
"
`B<R>' after you set them).
Type `|h' for a paged display if this was too hard to read.
"; # Fix balance of vi % matching: }}}}
# note: tabs in the following section are not-so-helpful
$pre580_summary = <<"END_SUM";
B<<>[B<<>]|B<{>[B<{>]|B<>>[B<>>] [I<cmd>] Do pre/post-prompt B<b> [I<ln>|I<event>|I<sub>] [I<cnd>] Set breakpoint
# ')}}; # Fix balance of vi % matching
} ## end sub sethelp
=head2 C<print_help()>
Most of what C<print_help> does is just text formatting. It finds the
C<B> and C<I> ornaments, cleans them off, and substitutes the proper
terminal control characters to simulate them (courtesy of
<Term::ReadLine::TermCap>).
=cut
sub print_help {
local $_ = shift;
# Restore proper alignment destroyed by eeevil I<> and B<>
# ornaments: A pox on both their houses!
#
# A help command will have everything up to and including
# the first tab sequence padded into a field 16 (or if indented 20)
# wide. If it's wider than that, an extra space will be added.
s{
^ # only matters at start of line
( \040{4} | \t )* # some subcommands are indented
( < ? # so <CR> works
[BI] < [^\t\n] + ) # find an eeevil ornament
( \t+ ) # original separation, discarded
( .* ) # this will now start (no earlier) than
# column 16
} {
# replace with this whole string:
. $command
. $text;
}mgex;
s{ # handle bold ornaments
B < ( [^>] + | > ) >
} {
. $1
}gex;
s{ # handle italic ornaments
I < ( [^>] + | > ) >
} {
. $1
}gex;
local $\ = '';
print $OUT $_;
} ## end sub print_help
=head2 C<fix_less>
This routine does a lot of gyrations to be sure that the pager is C<less>.
It checks for C<less> masquerading as C<more> and records the result in
C<$ENV{LESS}> so we don't have to go through doing the stats again.
=cut
sub fix_less {
# We already know if this is set.
# Pager is less for sure.
# Nope, set to more. See what's out there.
# is it really less, pretending to be more?
@st_less &&
} ## end if ($pager =~ /\bmore\b/)
# changes environment!
# 'r' added so we don't do (slow) stats again.
} ## end sub fix_less
=head1 DIE AND WARN MANAGEMENT
=head2 C<diesignal>
C<diesignal> is a just-drop-dead C<die> handler. It's most useful when trying
to debug a debugger problem.
It does its best to report the error that occurred, and then forces the
program, debugger, and everything to die.
=cut
sub diesignal {
local $frame = 0;
# No return value prints.
local $doret = -2;
# set the abort signal handling to the default (just terminate).
# If we enter the signal handler recursively, kill myself with an
# abort signal (so we just terminate).
kill 'ABRT', $$ if $panic++;
# If we can show detailed info, do so.
# Don't recursively enter the warn handler, since we're carping.
# Skip two levels before reporting traceback: we're skipping
# mydie and confess.
# Tell us all about it.
}
# No Carp. Tell us about the signal as best we can.
else {
local $\ = '';
}
# Drop dead.
kill 'ABRT', $$;
} ## end sub diesignal
=head2 C<dbwarn>
The debugger's own default C<$SIG{__WARN__}> handler. We load C<Carp> to
be able to get a stack trace, and output the warning message vi C<DB::dbwarn()>.
=cut
sub dbwarn {
local $frame = 0;
# No return value printing.
local $doret = -2;
# Turn off warn and die handling to prevent recursive entries to this
# routine.
# Load Carp if we can. If $^S is false (current thing being compiled isn't
# done yet), we may not be able to do a require.
eval { require Carp }
# require may be broken.
# Use the core warn() unless Carp loaded OK.
CORE::warn(@_,
"\nCannot print stack trace, load with -MCarp option to see stack"),
return
# Save the current values of $single and $trace, and then turn them off.
$single = 0;
$trace = 0;
# We can call Carp::longmess without its being "debugged" (which we
# don't want - we just want to use it!). Capture this for later.
# Restore $single and $trace to their original values.
# Use the debugger's own special way of printing warnings to print
# the stack trace message.
} ## end sub dbwarn
=head2 C<dbdie>
The debugger's own C<$SIG{__DIE__}> handler. Handles providing a stack trace
by loading C<Carp> and calling C<Carp::longmess()> to get it. We turn off
single stepping and tracing during the call to C<Carp::longmess> to avoid
debugging it - we just want to use it.
If C<dieLevel> is zero, we let the program being debugged handle the
exceptions. If it's 1, you get backtraces for any exception. If it's 2,
the debugger takes over all exception handling, printing a backtrace and
displaying the exception via its C<dbwarn()> routine.
=cut
sub dbdie {
local $frame = 0;
local $doret = -2;
my $i = 0;
my $ineval = 0;
my $sub;
if ($dieLevel > 2) {
&warn(@_); # Yell no matter what
return;
}
if ($dieLevel < 2) {
die @_ if $^S; # in eval propagate
}
# The code used to check $^S to see if compiliation of the current thing
# hadn't finished. We don't do it anymore, figuring eval is pretty stable.
eval { require Carp };
die (@_,
"\nCannot print stack trace, load with -MCarp option to see stack")
# We do not want to debug this chunk (automatic disabling works
# inside DB::DB, but not in Carp). Save $single and $trace, turn them off,
# get the stack trace from Carp::longmess (if possible), restore $signal
# and $trace, and then die with the stack trace.
$single = 0;
$trace = 0;
my $mess = "@_";
{
}
die $mess;
} ## end sub dbdie
=head2 C<warnlevel()>
Set the C<$DB::warnLevel> variable that stores the value of the
C<warnLevel> option. Calling C<warnLevel()> with a positive value
results in the debugger taking over all warning handlers. Setting
C<warnLevel> to zero leaves any warning handlers set up by the program
being debugged in place.
=cut
sub warnLevel {
if (@_) {
$warnLevel = shift;
if ($warnLevel) {
}
elsif ($prevwarn) {
}
} ## end if (@_)
} ## end sub warnLevel
=head2 C<dielevel>
Similar to C<warnLevel>. Non-zero values for C<dieLevel> result in the
C<DB::dbdie()> function overriding any other C<die()> handler. Setting it to
zero lets you use your own C<die()> handler.
=cut
sub dieLevel {
local $\ = '';
if (@_) {
$dieLevel = shift;
if ($dieLevel) {
# Always set it to dbdie() for non-zero values.
# No longer exists, so don't try to use it.
#$SIG{__DIE__} = \&DB::diehard if $dieLevel >= 2;
# If we've finished initialization, mention that stack dumps
# are enabled, If dieLevel is 1, we won't stack dump if we die
# in an eval().
print $OUT "Stack dump during die enabled",
if $I_m_init;
# XXX This is probably obsolete, given that diehard() is gone.
} ## end if ($dieLevel)
# Put the old one back if there was one.
elsif ($prevdie) {
print $OUT "Default die handler restored.\n";
}
} ## end if (@_)
$dieLevel;
} ## end sub dieLevel
=head2 C<signalLevel>
Number three in a series: set C<signalLevel> to zero to keep your own
takes over and handles them with C<DB::diesignal()>.
=cut
sub signalLevel {
if (@_) {
$signalLevel = shift;
if ($signalLevel) {
}
else {
}
} ## end if (@_)
} ## end sub signalLevel
=head1 SUBROUTINE DECODING SUPPORT
These subroutines are used during the C<x> and C<X> commands to try to
produce as much information as possible about a code reference. They use
L<Devel::Peek> to try to find the glob in which this code reference lives
(if it does) - this allows us to actually code references which correspond
to named subroutines (including those aliased via glob assignment).
=head2 C<CvGV_name()>
Wrapper for X<CvGV_name_or_bust>; tries to get the name of a reference
via that routine. If this fails, return the reference again (when the
reference is stringified, it'll come out as "SOMETHING(0X...)").
=cut
sub CvGV_name {
my $in = shift;
}
=head2 C<CvGV_name_or_bust> I<coderef>
Calls L<Devel::Peek> to try to find the glob the ref lives in; returns
C<undef> if L<Devel::Peek> can't be loaded, or if C<Devel::Peek::CvGV> can't
find a glob for this ref.
Returns "I<package>::I<glob name>" if the code ref is found in a glob.
=cut
sub CvGV_name_or_bust {
my $in = shift;
return if $skipCvGV; # Backdoor to avoid problems if XS broken...
return unless ref $in;
} ## end sub CvGV_name_or_bust
=head2 C<find_sub>
A utility routine used in various places; finds the file where a subroutine
was defined, and returns that filename and a line-number range.
Tries to use X<@sub> first; if it can't find it there, it tries building a
reference to the subroutine and uses X<CvGV_name_or_bust> to locate it,
loading it into X<@sub> as a side effect (XXX I think). If it can't find it
this way, it brute-force searches X<%sub>, checking for identical references.
=cut
sub find_sub {
my $subr = shift;
return unless defined &$subr;
my $data;
# Old stupid way...
my $s;
for (keys %sub) {
$s = $_, last if $subr eq \&$_;
}
$sub{$s} if $s;
} ## end do
} ## end sub find_sub
=head2 C<methods>
A subroutine that uses the utility function X<methods_via> to find all the
methods in the class corresponding to the current reference and in
C<UNIVERSAL>.
=cut
sub methods {
# Figure out the class - either this is the class or it's a reference
# to something blessed into that class.
my $class = shift;
local %seen;
local %packs;
# Show the methods that this class has.
# Show the methods that UNIVERSAL has.
} ## end sub methods
=head2 C<methods_via($class, $prefix, $crawl_upward)>
C<methods_via> does the work of crawling up the C<@ISA> tree and reporting
all the parent class methods. C<$class> is the name of the next class to
try; C<$prefix> is the message prefix, which gets built up as we go up the
C<@ISA> tree to show parentage; C<$crawl_upward> is 1 if we should try to go
higher in the C<@ISA> tree, 0 if we should stop.
=cut
sub methods_via {
# If we've processed this class already, just quit.
my $class = shift;
# This is a package that is contributing the methods we're about to print.
my $prefix = shift;
my $name;
for $name (
# Keep if this is a defined subroutine in this class.
grep { defined &{ ${"${class}::"}{$_} } }
# Extract from all the symbols in this class.
sort keys %{"${class}::"}
) {
# If we printed this already, skip it.
# Print the new method name.
local $\ = '';
local $, = '';
} ## end for $name (grep { defined...
# If the $crawl_upward argument is false, just quit here.
return unless shift;
# $crawl_upward true: keep going up the tree.
# Find all the classes this one is a subclass of.
for $name (@{"${class}::ISA"}) {
# Set up the new prefix.
# Crawl up the tree and keep trying to crawl up.
}
} ## end sub methods_via
=head2 C<setman> - figure out which command to use to show documentation
Just checks the contents of C<$^O> and sets the C<$doccmd> global accordingly.
=cut
sub setman {
$doccmd =
? "man" # O Happy Day!
: "perldoc"; # Alas, poor unfortunates
} ## end sub setman
=head2 C<runman> - run the appropriate command to show documentation
Accepts a man page name; runs the appropriate command to display it (set up
during debugger initialization). Uses C<DB::system> to avoid mucking up the
program's STDIN and STDOUT.
=cut
sub runman {
my $page = shift;
unless ($page) {
&system("$doccmd $doccmd");
return;
}
# this way user can override, like with $doccmd="man -Mwhatever"
# or even just "man " to disable the path check.
unless ($doccmd eq 'man') {
&system("$doccmd $page");
return;
}
require Config;
my $manpath = '';
# harmless if missing, I figure
if (
CORE::system(
$doccmd,
# I just *know* there are men without -M
split ' ', $page
)
)
{
if (
grep { $page eq $_ }
qw{
}
)
{
$page);
} ## end if (grep { $page eq $_...
} ## end unless ($page =~ /^perl\w/)
} ## end if (CORE::system($doccmd...
if (defined $oldpath) {
}
else {
}
} ## end sub runman
#use Carp; # This did break, left for debugging
=head1 DEBUGGER INITIALIZATION - THE SECOND BEGIN BLOCK
Because of the way the debugger interface to the Perl core is designed, any
debugger package globals that C<DB::sub()> requires have to be defined before
any subroutines can be called. These are defined in the second C<BEGIN> block.
This block sets things up so that (basically) the world is sane
before the debugger starts executing. We set up various variables that the
debugger has to have set up before the Perl core starts running:
=over 4
=item * The debugger's own filehandles (copies of STD and STDOUT for now).
=item * Characters for shell escapes, the recall command, and the history command.
=item * The maximum recursion depth.
=item * The size of a C<w> command's window.
=item * The before-this-line context to be printed in a C<v> (view a window around this line) command.
=item * The fact that we're not in a sub at all right now.
=item * The default SIGINT handler for the debugger.
=item * The appropriate value of the flag in C<$^D> that says the debugger is running
=item * The current debugger recursion level
=item * The list of postponed (XXX define) items and the C<$single> stack
=back
=cut
# The following BEGIN is very handy if debugger goes havoc, debugging debugger?
BEGIN { # This does not compile, alas. (XXX eh?)
# Define characters used by command parsing.
@truehist=(); # Can be saved for replay (per session)
# This defines the point at which you get the 'deep recursion'
# warning. It MUST be defined or the debugger will not load.
$deep = 100;
# Number of lines around the current one that are shown in the
# 'w' command.
$window = 10;
# How much before-the-current-line context the 'v' command should
# use in calculating the start of the window it will display.
$preview = 3;
# We're not in any sub yet, but we need this to be a defined value.
$sub = '';
# Set up the debugger's interrupt handler. It simply sets a flag
# ($signal) that DB::DB() will check before each command is executed.
# The following lines supposedly, if uncommented, allow the debugger to
# debug itself. Perhaps we can try that someday.
# This may be enabled to debug debugger:
#$warnLevel = 1 unless defined $warnLevel;
#$dieLevel = 1 unless defined $dieLevel;
#$signalLevel = 1 unless defined $signalLevel;
# This is the flag that says "a debugger is running, please call
# DB::DB and DB::sub". We will turn it on forcibly before we try to
# execute anything in the user's context, because we always want to
# get control back.
# This variable records how many levels we're nested in debugging. Used
# Used in the debugger prompt, and in determining whether it's all over or
# not.
# "Triggers bug (?) in perl if we postpone this until runtime."
# XXX No details on this yet, or whether we should fix the bug instead
# of work around it. Stay tuned.
# Used to track the current stack depth using the auto-stacked-variable
# trick.
# Don't print return values on exiting a subroutine.
$doret = -2;
$frame = 0;
} ## end BEGIN
BEGIN { $^W = $ini_warn; } # Switch warnings back
=head1 READLINE SUPPORT - COMPLETION FUNCTION
=head2 db_complete
C<readline> support - adds command completion to basic C<readline>.
Returns a list of possible completions to C<readline> when invoked. C<readline>
will print the longest common substring following the text already entered.
If there is only a single possible completion, C<readline> will use it in full.
This code uses C<map> and C<grep> heavily to create lists of possible
completion. Think LISP in this section.
=cut
sub db_complete {
# Specific code for b c l V m f O, &blah, $blah, @blah, %blah
# $text is the text to be completed.
# $line is the incoming line typed by the user.
# $start is the start of the text to be completed in the incoming line.
# Save the initial text.
# The search pattern is current package, ::, extract the next qualifier
# Prefix and pack are set to undef.
($text, "^\Q${'package'}::\E([^:]+)\$");
=over 4
=item * Find all the subroutines that might match in this package
=item * Add "postpone", "load", and "compile" as possibles (we may be completing the keyword itself
=item * Include all the rest of the subs that are known
=item * C<grep> out the ones that match the text we have so far
=item * Return this as the list of possible completions
=back
=cut
=cut
=cut
=cut
and $text =~ /^(.*[^:])::?(\w*)$/
and $prefix = $1;
=over 4
=item 1. The original source file itself
=item 2. A file from C<@INC>
=item 3. An C<eval> (the debugger gets a C<(eval N)> fake file for each C<eval>).
=back
=cut
if ($line =~ /^\|*f\s+(.*)/) { # Loaded files
# We might possibly want to switch to an eval (which has a "filename"
# like '(eval 9)'), so we may need to clean up the completion text
# before proceeding.
$text = $1;
=pod
(C<eval>s are C<_E<lt>(eval NNN)>) keys in C<%main::>. We pull all of these
out of C<%main::>, add the initial source file, and extract the ones that
match the completion text so far.
=cut
return sort
$0;
} ## end if ($line =~ /^\|*f\s+(.*)/)
=cut
$prefix = "&";
(
map { /$search/ ? ($1) : () }
keys %sub
);
} ## end if ((substr $text, 0, ...
=cut
if ($text =~ /^[\$@%](.*)::(.*)/) { # symbols in a package
=pod
=over 4
=item * Determine the package that the symbol is in. Put it in C<::> (effectively C<main::>) if no package is specified.
=cut
=pod
=item * Figure out the prefix vs. what needs completing.
=cut
$text = $2;
=pod
=item * Look through all the symbols in the package. C<grep> out all the possible hashes/arrays/scalars, and then C<grep> the possible matches out of those. C<map> the prefix onto all the possibilities.
=cut
keys %$pack;
=pod
=item * If there's only one hit, and it's a package qualifier, and it's not equal to the initial text, re-complete it using the symbol we actually found.
=cut
}
# Return the list of possibles.
return sort @out;
} ## end if ($text =~ /^[\$@%](.*)::(.*)/)
=pod
=back
=head3 Symbol completion: current package or package C<main>.
=cut
if ($text =~ /^[\$@%]/) { # symbols (in $package + packages in main)
=pod
=over 4
=item * If it's C<main>, delete main to just get C<::> leading.
=cut
=pod
=item * We set the prefix to the item's sigil, and trim off the sigil to get the text to be completed.
=cut
=pod
=item * If the package is C<::> (C<main>), create an empty list; if it's something else, create a list of all the packages known. Append whichever list to a list of all the possible symbols in the current package. C<grep> out the matches to the text entered so far, then C<map> the prefix back onto the symbols.
=cut
($pack eq '::' ? () : (grep /::$/, keys %::));
=item * If there's only one hit, it's a package qualifier, and it's not equal to the initial text, recomplete using this symbol.
=back
=cut
}
# Return the list of possibles.
return sort @out;
} ## end if ($text =~ /^[\$@%]/)
=cut
# We look for the text to be matched in the list of possible options,
# and fetch the current value.
# Set up a 'query option's value' command.
my $out = '? ';
# There's really nothing else we can do.
}
# We have a value. Create a proper option-setting command.
elsif ($val =~ /\s/) {
# XXX This may be an extraneous variable.
my $found;
# We'll want to quote the string (because of the embedded
# whtespace), but we want to make sure we don't end up with
# mismatched quote characters. We try several possibilities.
foreach $l (split //, qq/\"\'\#\|/) {
# If we didn't find this quote character in the value,
# quote it using this quote character.
}
} ## end elsif ($val =~ /\s/)
# Don't need any quotes.
else {
$out = "=$val ";
}
# If there were multiple possible values, return '? ', which
# makes the command into a query command. If there was just one,
# have readline append that.
# Return list of possibilities.
return sort @out;
} ## end if ((substr $line, 0, ...
=cut
} ## end sub db_complete
=head1 MISCELLANEOUS SUPPORT FUNCTIONS
Functions that possibly ought to be somewhere else.
=head2 end_report
Say we're done.
=cut
sub end_report {
local $\ = '';
print $OUT "Use `q' to quit or `R' to restart. `h q' for details.\n";
}
=head2 clean_ENV
If we have $ini_pids, save it in the environment; else remove it from the
environment. Used by the C<R> (restart) command.
=cut
sub clean_ENV {
if (defined($ini_pids)) {
}
else {
delete($ENV{PERLDB_PIDS});
}
} ## end sub clean_ENV
=head1 END PROCESSING - THE C<END> BLOCK
Come here at the very end of processing. We want to go into a
loop where we allow the user to enter commands and interact with the
debugger, but we don't want anything else to execute.
First we set the C<$finished> variable, so that some commands that
shouldn't be run after the end of program quit working.
We then figure out whether we're truly done (as in the user entered a C<q>
command, or we finished execution while running nonstop). If we aren't,
we set C<$single> to 1 (causing the debugger to get control again).
We then call C<DB::fake::at_exit()>, which returns the C<Use 'q' to quit ...">
message and returns control to the debugger. Repeat.
When the user finally enters a C<q> command, C<$fall_off_end> is set to
1 and the C<END> block simply exits with C<$single> set to 0 (don't
break, run to completion.).
=cut
END {
# Do not stop in at_exit() and destructors on exit:
} ## end END
=head1 PRE-5.8 COMMANDS
Some of the commands changed function quite a bit in the 5.8 command
realignment, so much so that the old code had to be replaced completely.
Because we wanted to retain the option of being able to go back to the
former command set, we moved the old code off to this section.
There's an awful lot of duplicated code here. We've duplicated the
comments to keep things clear.
=head2 Null command
Does nothing. Used to 'turn off' commands.
=cut
sub cmd_pre580_null {
# do nothing...
}
=head2 Old C<a> command.
This version added actions if you supplied them, and deleted them
if you didn't.
=cut
sub cmd_pre580_a {
my $xcmd = shift;
my $cmd = shift;
# Argument supplied. Add the action.
if ($cmd =~ /^(\d*)\s*(.*)/) {
# If the line isn't there, use the current line.
$i = $1 || $line;
$j = $2;
# If there is an action ...
if (length $j) {
# ... but the line isn't breakable, skip it.
if ($dbline[$i] == 0) {
print $OUT "Line $i may not have an action.\n";
}
else {
# ... and the line is breakable:
# Mark that there's an action in this file.
# Delete any current action.
# Add the new action, continuing the line as needed.
}
} ## end if (length $j)
# No action supplied.
else {
# Delete the action.
# Mark as having no break or action if nothing's left.
}
} ## end if ($cmd =~ /^(\d*)\s*(.*)/)
} ## end sub cmd_pre580_a
=head2 Old C<b> command
Add breakpoints.
=cut
sub cmd_pre580_b {
my $xcmd = shift;
my $cmd = shift;
my $dbline = shift;
# Break on load.
my $file = $1;
$file =~ s/\s+$//;
&cmd_b_load($file);
}
# b compile|postpone <some sub> [<condition>]
# The interpreter actually traps this one for us; we just put the
# necessary condition in the %postponed hash.
# Capture the condition if there is one. Make it true if none.
# Save the sub name and set $break to 1 if $1 was 'postpone', 0
# if it was 'compile'.
# De-Perl4-ify the name - ' separators to ::.
$subname =~ s/\'/::/g;
# Qualify it into the current package unless it's already qualified.
unless $subname =~ /::/;
# Add main if it starts with ::.
# Save the break type for this sub.
} ## end elsif ($cmd =~ ...
# b <sub name> [<condition>]
elsif ($cmd =~ /^([':A-Za-z_][':\w]*(?:\[.*\])?)\s*(.*)/) {
my $subname = $1;
}
# b <line> [<condition>].
elsif ($cmd =~ /^(\d*)\s*(.*)/) {
my $i = $1 || $dbline;
&cmd_b_line($i, $cond);
}
} ## end sub cmd_pre580_b
=head2 Old C<D> command.
Delete all breakpoints unconditionally.
=cut
sub cmd_pre580_D {
my $xcmd = shift;
my $cmd = shift;
if ($cmd =~ /^\s*$/) {
print $OUT "Deleting all breakpoints...\n";
# %had_breakpoints lists every file that had at least one
# breakpoint in it.
my $file;
for $file (keys %had_breakpoints) {
# Switch to the desired file temporarily.
my $max = $#dbline;
my $was;
# For all lines in this file ...
for ($i = 1 ; $i <= $max ; $i++) {
# If there's a breakpoint or action on this line ...
if (defined $dbline{$i}) {
# ... remove the breakpoint.
$dbline{$i} =~ s/^[^\0]+//;
if ($dbline{$i} =~ s/^\0?$//) {
# Remove the entry altogether if no action is there.
delete $dbline{$i};
}
} ## end if (defined $dbline{$i...
} ## end for ($i = 1 ; $i <= $max...
# If, after we turn off the "there were breakpoints in this file"
# bit, the entry in %had_breakpoints for this file is zero,
# we should remove this file from the hash.
delete $had_breakpoints{$file};
}
} ## end for $file (keys %had_breakpoints)
# Kill off all the other breakpoints that are waiting for files that
# haven't been loaded yet.
undef %postponed;
undef %postponed_file;
undef %break_on_load;
} ## end if ($cmd =~ /^\s*$/)
} ## end sub cmd_pre580_D
=head2 Old C<h> command
Print help. Defaults to printing the long-form help; the 5.8 version
prints the summary by default.
=cut
sub cmd_pre580_h {
my $xcmd = shift;
my $cmd = shift;
# Print the *right* help, long format.
if ($cmd =~ /^\s*$/) {
}
# 'h h' - explicitly-requested summary.
elsif ($cmd =~ /^h\s*/) {
}
# Find and print a command's help.
elsif ($cmd =~ /^h\s+(\S.*)$/) {
# XXX: finds CR but not <CR>
if ($pre580_help =~ /^
<? # Optional '<'
(?:[IB]<) # Optional markup
$qasked # The command name
/mx) {
while (
$pre580_help =~ /^
( # The command help:
<? # Optional '<'
(?:[IB]<) # Optional markup
$qasked # The command name
([\s\S]*?) # Lines starting with tabs
\n # Final newline
)
(?!\s)/mgx) # Line not starting with space
# (Next command's help)
{
print_help($1);
}
} ## end if ($pre580_help =~ /^<?(?:[IB]<)$qasked/m)
# Help not found.
else {
print_help("B<$asked> is not a debugger command.\n");
}
} ## end elsif ($cmd =~ /^h\s+(\S.*)$/)
} ## end sub cmd_pre580_h
=head2 Old C<W> command
C<W E<lt>exprE<gt>> adds a watch expression, C<W> deletes them all.
=cut
sub cmd_pre580_W {
my $xcmd = shift;
my $cmd = shift;
# Delete all watch expressions.
if ($cmd =~ /^$/) {
# No watching is going on.
$trace &= ~2;
# Kill all the watch expressions and values.
}
# Add a watch expression.
elsif ($cmd =~ /^(.*)/s) {
# add it to the list to be watched.
push @to_watch, $1;
# Get the current value of the expression.
# Doesn't handle expressions returning list values!
$evalarg = $1;
# Save it.
# We're watching stuff.
$trace |= 2;
} ## end elsif ($cmd =~ /^(.*)/s)
} ## end sub cmd_pre580_W
=head1 PRE-AND-POST-PROMPT COMMANDS AND ACTIONS
The debugger used to have a bunch of nearly-identical code to handle
the pre-and-post-prompt action commands. C<cmd_pre590_prepost> and
C<cmd_prepost> unify all this into one set of code to handle the
appropriate actions.
=head2 C<cmd_pre590_prepost>
A small wrapper around C<cmd_prepost>; it makes sure that the default doesn't
do something destructive. In pre 5.8 debuggers, the default action was to
delete all the actions.
=cut
sub cmd_pre590_prepost {
my $cmd = shift;
my $line = shift || '*';
my $dbline = shift;
} ## end sub cmd_pre590_prepost
=head2 C<cmd_prepost>
Actually does all the handling foe C<E<lt>>, C<E<gt>>, C<{{>, C<{>, etc.
Since the lists of actions are all held in arrays that are pointed to by
references anyway, all we have to do is pick the right array reference and
then use generic code to all, delete, or list actions.
=cut
# No action supplied defaults to 'list'.
my $line = shift || '?';
# Figure out what to put in the prompt.
my $which = '';
# Make sure we have some array or another to address later.
# This means that if ssome reason the tests fail, we won't be
# trying to stash actions or delete them from the wrong place.
my $aref = [];
# < - Perl code to run before prompt.
if ( $cmd =~ /^\</o ) {
$which = 'pre-perl';
}
# > - Perl code to run after prompt.
elsif ( $cmd =~ /^\>/o ) {
$which = 'post-perl';
}
# { - first check for properly-balanced braces.
elsif ( $cmd =~ /^\{/o ) {
print $OUT
"$cmd is now a debugger command\nuse `;$cmd' if you mean Perl code\n";
}
# Properly balanced. Pre-prompt debugger actions.
else {
$which = 'pre-debugger';
}
} ## end elsif ( $cmd =~ /^\{/o )
# Did we find something that makes sense?
unless ($which) {
print $OUT "Confused by command: $cmd\n";
}
# Yes.
else {
# List actions.
if ( $line =~ /^\s*\?\s*$/o ) {
unless (@$aref) {
# Nothing there. Complain.
print $OUT "No $which actions.\n";
}
else {
# List the actions in the selected list.
print $OUT "$which commands:\n";
print $OUT "\t$cmd -- $action\n";
}
} ## end else
} ## end if ( $line =~ /^\s*\?\s*$/o)
# Might be a delete.
else {
if ( length($cmd) == 1 ) {
if ( $line =~ /^\s*\*\s*$/o ) {
# It's a delete. Get rid of the old actions in the
# selected list..
@$aref = ();
print $OUT "All $cmd actions cleared.\n";
}
else {
# Replace all the actions. (This is a <, >, or {).
}
} ## end if ( length($cmd) == 1)
elsif ( length($cmd) == 2 ) {
# Add the action to the line. (This is a <<, >>, or {{).
}
else {
# <<<, >>>>, {{{{{{ ... something not a command.
print $OUT
"Confused by strange length of $which command($cmd)...\n";
}
} ## end else [ if ( $line =~ /^\s*\?\s*$/o)
} ## end else
} ## end sub cmd_prepost
=head1 C<DB::fake>
Contains the C<at_exit> routine that the debugger uses to issue the
C<Debugged program terminated ...> message after the program completes. See
the C<END> block documentation for more details.
=cut
sub at_exit {
"Debugged program terminated. Use `q' to quit or `R' to restart.";
}
1;