cmd/csh/sh.c

/*
 * Copyright (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*  Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */
/*    All Rights Reserved   */

/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved.  The Berkeley Software License Agreement
 * specifies the terms and conditions for redistribution.
 */

#include <locale.h>
#include "sh.h"
/* #include <sys/ioctl.h> */
#include <fcntl.h>
#include <sys/filio.h>
#include "sh.tconst.h"
#include <pwd.h>
#include <stdlib.h>
#ifdef  TRACE
#include <stdio.h>
#endif

/*
 * We use these csh(1) private versions of the select macros, (see select(3C))
 * so as not to be limited by the size of struct fd_set (ie 1024).
 */
#define CSH_FD_SET(n, p)   ((*((p) + ((n)/NFDBITS))) |= (1 << ((n) % NFDBITS)))
#define CSH_FD_CLR(n, p)   ((*((p) + ((n)/NFDBITS))) &= ~(1 << ((n) % NFDBITS)))
#define CSH_FD_ISSET(n, p) ((*((p) + ((n)/NFDBITS))) & (1 << ((n) % NFDBITS)))
#define CSH_FD_ZERO(p, n)  memset((void *)(p), 0,  (n))

tchar *pathlist[] = { S_usrbin /* "/usr/bin" */, S_DOT /* "." */, 0 };
tchar *dumphist[] = { S_history /* "history" */, S_h /* "-h" */, 0, 0 };
tchar *loadhist[] = { S_source /* "source" */, S_h /* "-h" */,
    S_NDOThistory /* "~/.history" */, 0 };
tchar HIST = '!';
tchar HISTSUB = '^';
int nofile;
bool    reenter;
bool    nverbose;
bool    nexececho;
bool    quitit;
bool    fast;
bool    batch;
bool    prompt = 1;
bool    enterhist = 0;

extern  gid_t getegid(), getgid();
extern  uid_t geteuid(), getuid();
extern tchar **strblktotsblk(/* char **, int */);

extern void hupforegnd(void);
void interactive_hup(void);
void interactive_login_hup(void);

void    importpath(tchar *);
void    srccat(tchar *, tchar *);
void    srccat_inlogin(tchar *, tchar *);
void    srcunit(int, bool, bool);
void    rechist(void);
void    goodbye(void);
void    pintr1(bool);
void    process(bool);
void    dosource(tchar **);
void    mailchk(void);
void    printprompt(void);
void    sigwaiting(void);
void    siglwp(void);
void    initdesc(int, char *[]);
void    initdesc_x(int, char *[], int);
void    closem(void);
void    unsetfd(int);
void    phup(void);

#ifdef  TRACE
FILE *trace;
/*
 * Trace routines
 */
#define TRACEFILE   "/tmp/trace.XXXXXX"

/*
 * Initialize trace file.
 * Called from main.
 */
void
trace_init(void)
{
    char name[128];
    char *p;

    strcpy(name, TRACEFILE);
    p = mktemp(name);
    trace = fopen(p, "w");
}

/*
 * write message to trace file
 */
/*VARARGS1*/
void
tprintf(fmt, a, b, c, d, e, f, g, h, i, j)
    char *fmt;
{
    if (trace) {
        fprintf(trace, fmt, a, b, c, d, e, f, g, h, i, j);
        fflush(trace);
    }
}
#endif

int
main(int c, char **av)
{
    tchar **v, *cp, *r;
    int f;
    struct sigvec osv;
    struct sigaction sa;
    tchar s_prompt[MAXHOSTNAMELEN+3];
    char *c_max_var_len;
    int c_max_var_len_size;

    /*
     * set up the error exit, if there is an error before
     * this is done, it will core dump, and we don't
     * tolerate core dumps
     */
    haderr = 0;
    setexit();
    if (haderr) {
        /*
         *  if were here, there was an error in the csh
         *  startup so just punt
         */
        printf("csh startup error, csh exiting...\n");
        flush();
        exitstat();
    }


    (void) setlocale(LC_ALL, "");
#if !defined(TEXT_DOMAIN)   /* Should be defined by cc -D */
#define TEXT_DOMAIN "SYS_TEST"  /* Use this only if it weren't */
#endif
    (void) textdomain(TEXT_DOMAIN);

    /* Copy arguments */
    v = strblktotsblk(av, c);

    /*
     * Initialize paraml list
     */
    paraml.next = paraml.prev = &paraml;

    settimes();         /* Immed. estab. timing base */

    if (eq(v[0], S_aout /* "a.out" */)) /* A.out's are quittable */
        quitit = 1;
    uid = getuid();
    loginsh = **v == '-';
    if (loginsh)
        (void) time(&chktim);

    /*
     * Move the descriptors to safe places.
     * The variable didfds is 0 while we have only FSH* to work with.
     * When didfds is true, we have 0,1,2 and prefer to use these.
     *
     * Also, setup data for csh internal file descriptor book keeping.
     */
    initdesc(c, av);

    /*
     * Initialize the shell variables.
     * ARGV and PROMPT are initialized later.
     * STATUS is also munged in several places.
     * CHILD is munged when forking/waiting
     */

    c_max_var_len_size = snprintf(NULL, 0, "%ld", MAX_VAR_LEN);
    c_max_var_len = (char *)xalloc(c_max_var_len_size + 1);
    (void) snprintf(c_max_var_len, (c_max_var_len_size + 1),
        "%ld", MAX_VAR_LEN);
    set(S_SUNW_VARLEN,  strtots(NOSTR, c_max_var_len));
    xfree(c_max_var_len);

    /* don't do globbing here, just set exact copies */
    setNS(S_noglob);

    set(S_status /* "status" */, S_0 /* "0" */);
    dinit(cp = getenvs_("HOME"));   /* dinit thinks that HOME==cwd in a */
                    /* login shell */
    if (cp == NOSTR)
        fast++;         /* No home -> can't read scripts */
    else {
        if (strlen_(cp) >= BUFSIZ - 10) {
            cp = NOSTR;
            fast++;
            printf("%s\n", gettext("Pathname too long"));
            set(S_home /* "home" */, savestr(cp));
            local_setenv(S_HOME, savestr(cp));
        }
        set(S_home /* "home" */, savestr(cp));
    }
    /*
     * Grab other useful things from the environment.
     * Should we grab everything??
     */
    if ((cp = getenvs_("USER")) != NOSTR)
        set(S_user /* "user" */, savestr(cp));
    else {
        /*
         * If USER is not defined, set it here.
         */
        struct passwd *pw;
        pw = getpwuid(getuid());

        if (pw != NULL) {
            set(S_user, strtots((tchar *)0, pw->pw_name));
            local_setenv(S_USER, strtots((tchar *)0, pw->pw_name));
        } else if (loginsh) { /* Give up setting USER variable. */
    printf("Warning: USER environment variable could not be set.\n");
        }
    }
    if ((cp = getenvs_("TERM")) != NOSTR)
        set(S_term /* "term" */, savestr(cp));
    /*
     * Re-initialize path if set in environment
     */
    if ((cp = getenvs_("PATH")) == NOSTR)
        set1(S_path /* "path" */, saveblk(pathlist), &shvhed);
    else
        importpath(cp);
    set(S_shell /* "shell" */, S_SHELLPATH);

    doldol = putn(getpid());        /* For $$ */

    /* restore globbing until the user says otherwise */
    unsetv(S_noglob);

    /*
     * Record the interrupt states from the parent process.
     * If the parent is non-interruptible our hand must be forced
     * or we (and our children) won't be either.
     * Our children inherit termination from our parent.
     * We catch it only if we are the login shell.
     */
        /* parents interruptibility */
    (void) sigvec(SIGINT, (struct sigvec *)0, &osv);
    parintr = osv.sv_handler;
        /* parents terminability */
    (void) sigvec(SIGTERM, (struct sigvec *)0, &osv);
    parterm = osv.sv_handler;

    _signal(SIGLWP, siglwp);
    _signal(SIGWAITING, sigwaiting);
    if (loginsh) {
        (void) signal(SIGHUP, phup);    /* exit processing on HUP */
        (void) signal(SIGXCPU, phup);   /* ...and on XCPU */
        (void) signal(SIGXFSZ, phup);   /* ...and on XFSZ */
    }

    /*
     * Process the arguments.
     *
     * Note that processing of -v/-x is actually delayed till after
     * script processing.
     */
    c--, v++;
    while (c > 0 && (cp = v[0])[0] == '-' && *++cp != '\0' && !batch) {
        do switch (*cp++) {

        case 'b':       /* -b   Next arg is input file */
            batch++;
            break;

        case 'c':       /* -c   Command input from arg */
            if (c == 1)
                exit(0);
            c--, v++;
            arginp = v[0];
            prompt = 0;
            nofile++;
            cflg++;
            break;

        case 'e':       /* -e   Exit on any error */
            exiterr++;
            break;

        case 'f':       /* -f   Fast start */
            fast++;
            break;

        case 'i':       /* -i   Interactive, even if !intty */
            intact++;
            nofile++;
            break;

        case 'n':       /* -n   Don't execute */
            noexec++;
            break;

        case 'q':       /* -q   (Undoc'd) ... die on quit */
            quitit = 1;
            break;

        case 's':       /* -s   Read from std input */
            nofile++;
            break;

        case 't':       /* -t   Read one line from input */
            onelflg = 2;
            prompt = 0;
            nofile++;
            break;
#ifdef TRACE
        case 'T':       /* -T   trace switch on */
            trace_init();
            break;
#endif

        case 'v':       /* -v   Echo hist expanded input */
            nverbose = 1;           /* ... later */
            break;

        case 'x':       /* -x   Echo just before execution */
            nexececho = 1;          /* ... later */
            break;

        case 'V':       /* -V   Echo hist expanded input */
            setNS(S_verbose /* "verbose" */);   /* NOW! */
            break;

        case 'X':       /* -X   Echo just before execution */
            setNS(S_echo /* "echo" */);     /* NOW! */
            break;

        } while (*cp);
        v++, c--;
    }

    if (quitit)         /* With all due haste, for debugging */
        (void) signal(SIGQUIT, SIG_DFL);

    /*
     * Unless prevented by -c, -i, -s, or -t, if there
     * are remaining arguments the first of them is the name
     * of a shell file from which to read commands.
     */
    if (!batch && (uid != geteuid() || getgid() != getegid())) {
        errno = EACCES;
        child++;            /* So this ... */
        Perror(S_csh /* "csh" */);  /* ... doesn't return */
    }

    if (nofile == 0 && c > 0) {
        nofile = open_(v[0], 0);
        if (nofile < 0) {
            child++;        /* So this ... */
            Perror(v[0]);       /* ... doesn't return */
        }
        file = v[0];
        SHIN = dmove(nofile, FSHIN);    /* Replace FSHIN */
        (void) fcntl(SHIN, F_SETFD, 1);
        prompt = 0;
        c--, v++;
    }

    /*
     * Consider input a tty if it really is or we are interactive.
     */
    intty = intact || isatty(SHIN);

    /*
     * Decide whether we should play with signals or not.
     * If we are explicitly told (via -i, or -) or we are a login
     * shell (arg0 starts with -) or the input and output are both
     * the ttys("csh", or "csh</dev/ttyx>/dev/ttyx")
     * Note that in only the login shell is it likely that parent
     * may have set signals to be ignored
     */
    if (loginsh || intact || intty && isatty(SHOUT))
        setintr = 1;
#ifdef TELL
    settell();
#endif
    /*
     * Save the remaining arguments in argv.
     */
    setq(S_argv /* "argv" */, copyblk(v), &shvhed);

    /*
     * Set up the prompt.
     */
    if (prompt) {
        gethostname_(s_prompt, MAXHOSTNAMELEN);
        strcat_(s_prompt,
            uid == 0 ? S_SHARPSP /* "# " */ : S_PERSENTSP /* "% " */);
        set(S_prompt /* "prompt" */, s_prompt);
    }

    /*
     * If we are an interactive shell, then start fiddling
     * with the signals; this is a tricky game.
     */
    shpgrp = getpgid(0);
    opgrp = tpgrp = -1;
    if (setintr) {
        **av = '-';
        if (!quitit)        /* Wary! */
            (void) signal(SIGQUIT, SIG_IGN);
        (void) signal(SIGINT, pintr);
        (void) sigblock(sigmask(SIGINT));
        (void) signal(SIGTERM, SIG_IGN);

        /*
         * Explicitly terminate foreground jobs and exit if we are
         * interactive shell
         */
        if (loginsh) {
            (void) signal(SIGHUP, interactive_login_hup);
        } else {
            (void) signal(SIGHUP, interactive_hup);
        }

        if (quitit == 0 && arginp == 0) {
            (void) signal(SIGTSTP, SIG_IGN);
            (void) signal(SIGTTIN, SIG_IGN);
            (void) signal(SIGTTOU, SIG_IGN);
            /*
             * Wait till in foreground, in case someone
             * stupidly runs
             *  csh &
             * dont want to try to grab away the tty.
             */
            if (isatty(FSHDIAG))
                f = FSHDIAG;
            else if (isatty(FSHOUT))
                f = FSHOUT;
            else if (isatty(OLDSTD))
                f = OLDSTD;
            else
                f = -1;
retry:
            if (ioctl(f, TIOCGPGRP,  (char *)&tpgrp) == 0 &&
                tpgrp != -1) {
                if (tpgrp != shpgrp) {
                    void (*old)() = (void (*)())
                        signal(SIGTTIN, SIG_DFL);
                    (void) kill(0, SIGTTIN);
                    (void) signal(SIGTTIN, old);
                    goto retry;
                }
                opgrp = shpgrp;
                shpgrp = getpid();
                tpgrp = shpgrp;
                (void) setpgid(0, shpgrp);
                (void) ioctl(f, TIOCSPGRP,  (char *)&shpgrp);
                (void) fcntl(dcopy(f, FSHTTY), F_SETFD, 1);
            } else {
notty:
printf("Warning: no access to tty; thus no job control in this shell...\n");
                tpgrp = -1;
            }
        }
    }
    if (setintr == 0 && parintr == SIG_DFL)
        setintr++;

    /*
     * Set SIGCHLD handler, making sure that reads restart after it runs.
     */
    sigemptyset(&sa.sa_mask);
    sa.sa_handler = pchild;
    sa.sa_flags = SA_RESTART;
    (void) sigaction(SIGCHLD, &sa, (struct sigaction *)NULL);

    /*
     * Set an exit here in case of an interrupt or error reading
     * the shell start-up scripts.
     */
    setexit();
    haderr = 0;     /* In case second time through */
    if (!fast && reenter == 0) {
        reenter++;

        /*
         * If this is a login csh, and /etc/.login exists,
         * source /etc/.login first.
         */
        if (loginsh) {
            tchar tmp_etc[4+1]; /* strlen("/etc")+1 */
            tchar tmp_login[7+1];   /* strlen("/.login")+1 */

            strtots(tmp_etc, "/etc");
            strtots(tmp_login, "/.login");
            srccat_inlogin(tmp_etc, tmp_login);
        }

        /* Will have value("home") here because set fast if don't */
        srccat(value(S_home /* "home" */),
            S_SLADOTcshrc /* "/.cshrc" */);

        /* Hash path */
        if (!fast && !arginp && !onelflg && !havhash)
            dohash(xhash);


        /*
         * Reconstruct the history list now, so that it's
         * available from within .login.
         */
        dosource(loadhist);
        if (loginsh) {
            srccat_inlogin(value(S_home /* "home" */),
                S_SLADOTlogin /* "/.login" */);
        }

        /*
         * To get cdpath hashing $cdpath must have a
         * value, not $CDPATH.  So if after reading
         * the startup files ( .cshrc ), and
         * user has specified a value for cdpath, then
         * cache $cdpath paths. xhash2 is global array
         * for $cdpath caching.
         */
        if (!fast && !arginp && !onelflg && !havhash2)
                dohash(xhash2);
    }

    /*
     * Now are ready for the -v and -x flags
     */
    if (nverbose)
        setNS(S_verbose /* "verbose" */);
    if (nexececho)
        setNS(S_echo /* "echo" */);

    /*
     * All the rest of the world is inside this call.
     * The argument to process indicates whether it should
     * catch "error unwinds".  Thus if we are a interactive shell
     * our call here will never return by being blown past on an error.
     */
    process(setintr);

    /*
     * Mop-up.
     */
    if (loginsh) {
        printf("logout\n");
        (void) close(SHIN); /* No need for unsetfd(). */
        child++;
        goodbye();
    }
    rechist();
    exitstat();
}

void
untty(void)
{

    if (tpgrp > 0) {
        (void) setpgid(0, opgrp);
        (void) ioctl(FSHTTY, TIOCSPGRP,  (char *)&opgrp);
    }
}

void
importpath(tchar *cp)
{
    int i = 0;
    tchar *dp;
    tchar **pv;
    int c;
    static tchar dot[2] = {'.', 0};

    for (dp = cp; *dp; dp++)
        if (*dp == ':')
            i++;
    /*
     * i+2 where i is the number of colons in the path.
     * There are i+1 directories in the path plus we need
     * room for a zero terminator.
     */
    pv =  (tchar **)xcalloc((unsigned)(i + 2), sizeof (tchar **));
    dp = cp;
    i = 0;
    if (*dp)
    for (;;) {
        if ((c = *dp) == ':' || c == 0) {
            *dp = 0;
            pv[i++] = savestr(*cp ? cp : dot);
            if (c) {
                cp = dp + 1;
                *dp = ':';
            } else
                break;
        }
        dp++;
    }
    pv[i] = 0;
    set1(S_path /* "path" */, pv, &shvhed);
}

/*
 * Source to the file which is the catenation of the argument names.
 */
void
srccat(tchar *cp, tchar *dp)
{
    tchar *ep = strspl(cp, dp);
    int unit = dmove(open_(ep, 0), -1);

    (void) fcntl(unit, F_SETFD, 1);
    xfree(ep);
#ifdef INGRES
    srcunit(unit, 0, 0);
#else
    srcunit(unit, 1, 0);
#endif
}

/*
 * Source to the file which is the catenation of the argument names.
 *  This one does not check the ownership.
 */
void
srccat_inlogin(tchar *cp, tchar *dp)
{
    tchar *ep = strspl(cp, dp);
    int unit = dmove(open_(ep, 0), -1);

    (void) fcntl(unit, F_SETFD, 1);
    xfree(ep);
    srcunit(unit, 0, 0);
}

/*
 * Source to a unit.  If onlyown it must be our file or our group or
 * we don't chance it.  This occurs on ".cshrc"s and the like.
 */
void
srcunit(int unit, bool onlyown, bool hflg)
{
    /* We have to push down a lot of state here */
    /* All this could go into a structure */
    int oSHIN = -1, oldintty = intty;
    struct whyle *oldwhyl = whyles;
    tchar *ogointr = gointr, *oarginp = arginp;
    tchar *oevalp = evalp, **oevalvec = evalvec;
    int oonelflg = onelflg;
    bool oenterhist = enterhist;
    tchar OHIST = HIST;
#ifdef TELL
    bool otell = cantell;
#endif
    struct Bin saveB;

    /* The (few) real local variables */
    jmp_buf oldexit;
    int reenter, omask;

    if (unit < 0)
        return;
    if (didfds)
        donefds();
    if (onlyown) {
        struct stat stb;

        if (fstat(unit, &stb) < 0 ||
            (stb.st_uid != uid && stb.st_gid != getgid())) {
            (void) close(unit);
            unsetfd(unit);
            return;
        }
    }

    /*
     * There is a critical section here while we are pushing down the
     * input stream since we have stuff in different structures.
     * If we weren't careful an interrupt could corrupt SHIN's Bin
     * structure and kill the shell.
     *
     * We could avoid the critical region by grouping all the stuff
     * in a single structure and pointing at it to move it all at
     * once.  This is less efficient globally on many variable references
     * however.
     */
    getexit(oldexit);
    reenter = 0;
    if (setintr)
        omask = sigblock(sigmask(SIGINT));
    setexit();
    reenter++;
    if (reenter == 1) {
        /* Setup the new values of the state stuff saved above */
        copy((char *)&saveB, (char *)&B, sizeof (saveB));
        fbuf =  (tchar **) 0;
        fseekp = feobp = fblocks = 0;
        oSHIN = SHIN, SHIN = unit, arginp = 0, onelflg = 0;
        intty = isatty(SHIN), whyles = 0, gointr = 0;
        evalvec = 0; evalp = 0;
        enterhist = hflg;
        if (enterhist)
            HIST = '\0';
        /*
         * Now if we are allowing commands to be interrupted,
         * we let ourselves be interrupted.
         */
        if (setintr)
            (void) sigsetmask(omask);
#ifdef TELL
        settell();
#endif
        process(0);     /* 0 -> blow away on errors */
    }
    if (setintr)
        (void) sigsetmask(omask);
    if (oSHIN >= 0) {
        int i;

        /* We made it to the new state... free up its storage */
        /* This code could get run twice but xfree doesn't care */
        for (i = 0; i < fblocks; i++)
            xfree(fbuf[i]);
        xfree((char *)fbuf);

        /* Reset input arena */
        copy((char *)&B, (char *)&saveB, sizeof (B));

        (void) close(SHIN), SHIN = oSHIN;
        unsetfd(SHIN);
        arginp = oarginp, onelflg = oonelflg;
        evalp = oevalp, evalvec = oevalvec;
        intty = oldintty, whyles = oldwhyl, gointr = ogointr;
        if (enterhist)
            HIST = OHIST;
        enterhist = oenterhist;
#ifdef TELL
        cantell = otell;
#endif
    }

    resexit(oldexit);
    /*
     * If process reset() (effectively an unwind) then
     * we must also unwind.
     */
    if (reenter >= 2)
        error(NULL);
}

void
rechist(void)
{
    tchar buf[BUFSIZ];
    int fp, ftmp, oldidfds;

    if (!fast) {
        if (value(S_savehist /* "savehist" */)[0] == '\0')
            return;
        (void) strcpy_(buf, value(S_home /* "home" */));
        (void) strcat_(buf, S_SLADOThistory /* "/.history" */);
        fp = creat_(buf, 0666);
        if (fp == -1)
            return;
        oldidfds = didfds;
        didfds = 0;
        ftmp = SHOUT;
        SHOUT = fp;
        (void) strcpy_(buf, value(S_savehist /* "savehist" */));
        dumphist[2] = buf;
        dohist(dumphist);
        (void) close(fp);
        unsetfd(fp);
        SHOUT = ftmp;
        didfds = oldidfds;
    }
}

void
goodbye(void)
{
    if (loginsh) {
        (void) signal(SIGQUIT, SIG_IGN);
        (void) signal(SIGINT, SIG_IGN);
        (void) signal(SIGTERM, SIG_IGN);
        setintr = 0;        /* No interrupts after "logout" */
        if (adrof(S_home /* "home" */))
            srccat(value(S_home /* "home" */),
                S_SLADOTlogout /* "/.logout" */);
    }
    rechist();
    exitstat();
}

void
exitstat(void)
{

#ifdef PROF
    monitor(0);
#endif
    /*
     * Note that if STATUS is corrupted (i.e. getn bombs)
     * then error will exit directly because we poke child here.
     * Otherwise we might continue unwarrantedly (sic).
     */
    child++;
    untty();
    exit(getn(value(S_status /* "status" */)));
}

/*
 * in the event of a HUP we want to save the history
 */
void
phup(void)
{
    rechist();
    exit(1);
}

void
interactive_hup(void)
{
    hupforegnd();
    exit(1);
}

void
interactive_login_hup(void)
{
    rechist();
    hupforegnd();
    exit(1);
}

tchar *jobargv[2] = { S_jobs /* "jobs" */, 0 };
/*
 * Catch an interrupt, e.g. during lexical input.
 * If we are an interactive shell, we reset the interrupt catch
 * immediately.  In any case we drain the shell output,
 * and finally go through the normal error mechanism, which
 * gets a chance to make the shell go away.
 */
void
pintr(void)
{
    pintr1(1);
}

void
pintr1(bool wantnl)
{
    tchar **v;
    int omask;

    omask = sigblock(0);
    if (setintr) {
        (void) sigsetmask(omask & ~sigmask(SIGINT));
        if (pjobs) {
            pjobs = 0;
            printf("\n");
            dojobs(jobargv);
            bferr("Interrupted");
        }
    }
    (void) sigsetmask(omask & ~sigmask(SIGCHLD));
    draino();

    /*
     * If we have an active "onintr" then we search for the label.
     * Note that if one does "onintr -" then we shan't be interruptible
     * so we needn't worry about that here.
     */
    if (gointr) {
        search(ZGOTO, 0, gointr);
        timflg = 0;
        if (v = pargv)
            pargv = 0, blkfree(v);
        if (v = gargv)
            gargv = 0, blkfree(v);
        reset();
    } else if (intty && wantnl)
        printf("\n");       /* Some like this, others don't */
    error(NULL);
}

/*
 * Process is the main driving routine for the shell.
 * It runs all command processing, except for those within { ... }
 * in expressions (which is run by a routine evalav in sh.exp.c which
 * is a stripped down process), and `...` evaluation which is run
 * also by a subset of this code in sh.glob.c in the routine backeval.
 *
 * The code here is a little strange because part of it is interruptible
 * and hence freeing of structures appears to occur when none is necessary
 * if this is ignored.
 *
 * Note that if catch is not set then we will unwind on any error.
 * If an end-of-file occurs, we return.
 */
void
process(bool catch)
{
    jmp_buf osetexit;
    struct command *t;

    getexit(osetexit);
    for (;;) {
        pendjob();
        freelex(&paraml);
        paraml.next = paraml.prev = &paraml;
        paraml.word = S_ /* "" */;
        t = 0;
        setexit();
        justpr = enterhist; /* execute if not entering history */

        /*
         * Interruptible during interactive reads
         */
        if (setintr)
            (void) sigsetmask(sigblock(0) & ~sigmask(SIGINT));

        /*
         * For the sake of reset()
         */
        freelex(&paraml), freesyn(t), t = 0;

        if (haderr) {
            if (!catch) {
                /* unwind */
                doneinp = 0;
                resexit(osetexit);
                reset();
            }
            haderr = 0;
            /*
             * Every error is eventually caught here or
             * the shell dies.  It is at this
             * point that we clean up any left-over open
             * files, by closing all but a fixed number
             * of pre-defined files.  Thus routines don't
             * have to worry about leaving files open due
             * to deeper errors... they will get closed here.
             */
            closem();
            continue;
        }
        if (doneinp) {
            doneinp = 0;
            break;
        }
        if (chkstop)
            chkstop--;
        if (neednote)
            pnote();
        if (intty && prompt && evalvec == 0) {
            mailchk();
            /*
             * If we are at the end of the input buffer
             * then we are going to read fresh stuff.
             * Otherwise, we are rereading input and don't
             * need or want to prompt.
             */
            if (fseekp == feobp)
                printprompt();
        }
        err = 0;

        /*
         * Echo not only on VERBOSE, but also with history expansion.
         */
        if (lex(&paraml) && intty ||
            adrof(S_verbose /* "verbose" */)) {
            haderr = 1;
            prlex(&paraml);
            haderr = 0;
        }

        /*
         * The parser may lose space if interrupted.
         */
        if (setintr)
            (void) sigblock(sigmask(SIGINT));

        /*
         * Save input text on the history list if
         * reading in old history, or it
         * is from the terminal at the top level and not
         * in a loop.
         */
        if (enterhist || catch && intty && !whyles)
            savehist(&paraml);

        /*
         * Print lexical error messages, except when sourcing
         * history lists.
         */
        if (!enterhist && err)
            error("%s", gettext(err));

        /*
         * If had a history command :p modifier then
         * this is as far as we should go
         */
        if (justpr)
            reset();

        alias(&paraml);

        /*
         * Parse the words of the input into a parse tree.
         */
        t = syntax(paraml.next, &paraml, 0);
        if (err)
            error("%s", gettext(err));

        /*
         * Execute the parse tree
         */
        {
            /*
             * POSIX requires SIGCHLD to be held
             * until all processes have joined the
             * process group in order to avoid race
             * condition.
             */
            int omask;

            omask = sigblock(sigmask(SIGCHLD));
            execute(t, tpgrp);
            (void) sigsetmask(omask &~ sigmask(SIGCHLD));
        }

        if (err)
            error("%s", gettext(err));
        /*
         * Made it!
         */
        freelex(&paraml), freesyn(t);
    }
    resexit(osetexit);
}

void
dosource(tchar **t)
{
    tchar *f;
    int u;
    bool hflg = 0;
    tchar buf[BUFSIZ];

    t++;
    if (*t && eq(*t, S_h /* "-h" */)) {
        if (*++t == NOSTR)
            bferr("Too few arguments.");
        hflg++;
    }
    (void) strcpy_(buf, *t);
    f = globone(buf);
    u = dmove(open_(f, 0), -1);
    xfree(f);
    freelex(&paraml);
    if (u < 0 && !hflg)
        Perror(f);
    (void) fcntl(u, F_SETFD, 1);
    srcunit(u, 0, hflg);
}

/*
 * Check for mail.
 * If we are a login shell, then we don't want to tell
 * about any mail file unless its been modified
 * after the time we started.
 * This prevents us from telling the user things he already
 * knows, since the login program insists on saying
 * "You have mail."
 */
void
mailchk(void)
{
    struct varent *v;
    tchar **vp;
    time_t t;
    int intvl, cnt;
    struct stat stb;
    bool new;

    v = adrof(S_mail /* "mail" */);
    if (v == 0)
        return;
    (void) time(&t);
    vp = v->vec;
    cnt = blklen(vp);
    intvl = (cnt && number(*vp)) ? (--cnt, getn(*vp++)) : MAILINTVL;
    if (intvl < 1)
        intvl = 1;
    if (chktim + intvl > t)
        return;
    for (; *vp; vp++) {
        if (stat_(*vp, &stb) < 0)
            continue;
        new = stb.st_mtime > time0.tv_sec;
        if (stb.st_size == 0 || stb.st_atime >= stb.st_mtime ||
            (stb.st_atime <= chktim && stb.st_mtime <= chktim) ||
            loginsh && !new)
            continue;
        if (cnt == 1)
            printf("You have %smail.\n", new ? "new " : "");
        else
            printf("%s in %t.\n", new ? "New mail" : "Mail", *vp);
    }
    chktim = t;
}

/*
 * Extract a home directory from the password file
 * The argument points to a buffer where the name of the
 * user whose home directory is sought is currently.
 * We write the home directory of the user back there.
 */
int
gethdir(tchar *home)
{
    /* getpwname will not be modified, so we need temp. buffer */
    char home_str[BUFSIZ];
    tchar home_ts[BUFSIZ];
    struct passwd *pp /* = getpwnam(home) */;

    pp = getpwnam(tstostr(home_str, home));
    if (pp == 0)
        return (1);
    (void) strcpy_(home, strtots(home_ts, pp->pw_dir));
    return (0);
}


#if 0
void
#ifdef PROF
done(int i)
#else
exit(int i)
#endif
{

    untty();
    _exit(i);
}
#endif

void
printprompt(void)
{
    tchar *cp;

    if (!whyles) {
        /*
         * Print the prompt string
         */
        for (cp = value(S_prompt /* "prompt" */); *cp; cp++)
            if (*cp == HIST)
                printf("%d", eventno + 1);
            else {
                if (*cp == '\\' && cp[1] == HIST)
                    cp++;
                Putchar(*cp | QUOTE);
            }
    } else
        /*
         * Prompt for forward reading loop
         * body content.
         */
        printf("? ");
    flush();
}

/*
 * Save char * block.
 */
tchar **
strblktotsblk(char **v, int num)
{
    tchar **newv =
        (tchar **)xcalloc((unsigned)(num+ 1), sizeof (tchar **));
    tchar **onewv = newv;

    while (*v && num--)
        *newv++ = strtots(NOSTR, *v++);
    *newv = 0;
    return (onewv);
}

void
sigwaiting(void)
{
    _signal(SIGWAITING, sigwaiting);
}

void
siglwp(void)
{
    _signal(SIGLWP, siglwp);
}


/*
 * Following functions and data are used for csh to do its
 * file descriptors book keeping.
 */

static int *fdinuse = NULL; /* The list of files opened by csh */
static int nbytesused = 0;  /* no of bytes allocated to fdinuse */
static int max_fd = 0;      /* The maximum descriptor in fdinuse */
static int my_pid;      /* The process id set in initdesc() */
static int NoFile = NOFILE; /* The number of files I can use. */

/*
 * Get the number of files this csh can use.
 *
 * Move the initial descriptors to their eventual
 * resting places, closing all other units.
 *
 * Also, reserve 0/1/2, so NIS+ routines do not get
 * hold of them. And initialize fdinuse list and set
 * the current process id.
 *
 * If this csh was invoked from setuid'ed script file,
 * do not close the third argument passed. The file
 * must be one of /dev/fd/0,1,2,,,
 *  (execv() always passes three arguments when it execs a script
 *   file in a form of #! /bin/csh -b.)
 *
 * If is_reinit is set in initdesc_x(), then we only close the file
 * descriptors that we actually opened (as recorded in fdinuse).
 */
void
initdesc(int argc, char *argv[])
{
    initdesc_x(argc, argv, 0);
}

void
reinitdesc(int argc, char *argv[])
{
    initdesc_x(argc, argv, 1);
}

/*
 * Callback functions for closing all file descriptors.
 */
static int
close_except(void *cd, int fd)
{
    int script_fd = *(int *)cd;

    if (fd >= 3 && fd < NoFile && fd != script_fd)
        (void) close(fd);
    return (0);
}

static int
close_inuse(void *cd, int fd)
{
    int script_fd = *(int *)cd;

    if (fd >= 3 && fd < NoFile && fd != script_fd &&
        CSH_FD_ISSET(fd, fdinuse)) {
        (void) close(fd);
        unsetfd(fd);
    }
    return (0);
}

void
initdesc_x(int argc, char *argv[], int is_reinit)
{

    int script_fd = -1;
    struct stat buf;
    struct rlimit rlp;

    /*
     * Get pid of this shell
     */
    my_pid = getpid();

    /*
     * Get the hard limit numbers of descriptors
     * this csh can use.
     */
    if (getrlimit(RLIMIT_NOFILE, &rlp) == 0)
        NoFile = rlp.rlim_cur;

    /*
     * If this csh was invoked for executing setuid script file,
     * the third argument passed is the special file name
     * which should not be closed.  This special file name is
     * in the form /dev/fd/X.
     */
    if (argc >= 3)
        if (sscanf(argv[2], "/dev/fd/%d", &script_fd) != 1)
            script_fd = -1;
        else
            /* Make sure to close this file on exec.  */
            fcntl(script_fd, F_SETFD, 1);

    if (fdinuse == NULL) {
        nbytesused = sizeof (int) *
            howmany(NoFile, sizeof (int) * NBBY);
        fdinuse = (int *)xalloc(nbytesused);
    }

    /*
     * Close all files except 0/1/2 to get a clean
     * file descritor space.
     */
    if (!is_reinit)
        (void) fdwalk(close_except, &script_fd);
    else
        (void) fdwalk(close_inuse, &script_fd);

    didfds = 0;         /* 0, 1, 2 aren't set up */

    if (fstat(0, &buf) < 0)
        open("/dev/null", 0);

    (void) fcntl(SHIN = dcopy(0, FSHIN), F_SETFD,  1);
    (void) fcntl(SHOUT = dcopy(1, FSHOUT), F_SETFD,  1);
    (void) fcntl(SHDIAG = dcopy(2, FSHDIAG), F_SETFD,  1);
    (void) fcntl(OLDSTD = dcopy(SHIN, FOLDSTD), F_SETFD,  1);

    /*
     * Open 0/1/2 to avoid Nis+ functions to pick them up.
     *  Now, 0/1/2 are saved, close them and open them.
     */
    close(0); close(1); close(2);
    open("/dev/null", 0);
    dup(0);
    dup(0);

    /*
     * Clear fd_set mask
     */
    if (!is_reinit)
        CSH_FD_ZERO(fdinuse, nbytesused);
}

/*
 * This routine is called after an error to close up
 * any units which may have been left open accidentally.
 *
 * You only need to remove files in fdinuse list.
 * After you have removed the files, you can clear the
 * list and max_fd.
 */
void
closem(void)
{
    int f;

    for (f = 3; f <= max_fd; f++) {
        if (CSH_FD_ISSET(f, fdinuse) &&
            f != SHIN && f != SHOUT && f != SHDIAG &&
            f != OLDSTD && f != FSHTTY)
            close(f);
    }
    CSH_FD_ZERO(fdinuse, nbytesused);
    max_fd = 0;
}

/*
 * Reset my_pid when a new process is created.  Only call this
 * if you want the process to affect fdinuse (e.g., fork, but
 * not vfork).
 */
void
new_process(void)
{
    my_pid = getpid();
}


/*
 * Whenever Csh open/create/dup/pipe a file or files,
 * Csh keeps track of its open files. The open files
 * are kept in "fdinuse, Fd In Use" list.
 *
 * When a file descriptor is newly allocated, setfd() is
 * used to mark the fact in "fdinuse" list.
 *  For example,
 *      fd = open("newfile", 0);
 *      setfd(fd);
 *
 * When a file is freed by close() function, unsetfd() is
 * used to remove the fd from "fdinuse" list.
 *  For example,
 *      close(fd);
 *      unsetfd(fd);
 */
void
setfd(int fd)
{
    /*
     * Because you want to avoid
     * conflict due to vfork().
     */
    if (my_pid != getpid())
        return;

    if (fd >= NoFile || fd < 0)
        return;

    if (fd > max_fd)
        max_fd = fd;
    CSH_FD_SET(fd, fdinuse);
}

void
unsetfd(int fd)
{
    int i;

    /*
     * Because you want to avoid
     * conflict due to vfork().
     */
    if (my_pid != getpid())
        return;

    if (fd >= NoFile || fd < 0)
        return;

    CSH_FD_CLR(fd, fdinuse);
    if (fd == max_fd) {
        for (i = max_fd-1; i >= 3; i--)
            if (CSH_FD_ISSET(i, fdinuse)) {
                max_fd = i;
                return;
            }
        max_fd = 0;
    }
}