/*
* Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#ifndef SHARE_VM_SERVICES_DIAGNOSTICFRAMEWORK_HPP
#define SHARE_VM_SERVICES_DIAGNOSTICFRAMEWORK_HPP
#include "classfile/vmSymbols.hpp"
#include "memory/allocation.hpp"
#include "runtime/arguments.hpp"
#include "runtime/os.hpp"
#include "runtime/vm_version.hpp"
#include "runtime/vmThread.hpp"
#include "utilities/ostream.hpp"
// CmdLine is the class used to handle a command line containing a single
// diagnostic command and its arguments. It provides methods to access the
// command name and the beginning of the arguments. The class is also
// able to identify commented command lines and the "stop" keyword
class CmdLine : public StackObj {
private:
const char* _cmd;
size_t _cmd_len;
const char* _args;
size_t _args_len;
public:
CmdLine(const char* line, size_t len, bool no_command_name);
const char* args_addr() const { return _args; }
size_t args_len() const { return _args_len; }
const char* cmd_addr() const { return _cmd; }
size_t cmd_len() const { return _cmd_len; }
bool is_empty() { return _cmd_len == 0; }
bool is_executable() { return is_empty() || _cmd[0] != '#'; }
bool is_stop() { return !is_empty() && strncmp("stop", _cmd, _cmd_len) == 0; }
};
// Iterator class taking a character string in input and returning a CmdLine
// instance for each command line. The argument delimiter has to be specified.
class DCmdIter : public StackObj {
friend class DCmd;
private:
const char* _str;
char _delim;
size_t _len;
size_t _cursor;
public:
DCmdIter(const char* str, char delim) {
_str = str;
_delim = delim;
_len = strlen(str);
_cursor = 0;
}
bool has_next() { return _cursor < _len; }
CmdLine next() {
assert(_cursor <= _len, "Cannot iterate more");
size_t n = _cursor;
while (n < _len && _str[n] != _delim) n++;
CmdLine line(&(_str[_cursor]), n - _cursor, false);
_cursor = n + 1;
// The default copy constructor of CmdLine is used to return a CmdLine
// instance to the caller.
return line;
}
};
// Iterator class to iterate over diagnostic command arguments
class DCmdArgIter : public ResourceObj {
const char* _buffer;
size_t _len;
size_t _cursor;
const char* _key_addr;
size_t _key_len;
const char* _value_addr;
size_t _value_len;
char _delim;
public:
DCmdArgIter(const char* buf, size_t len, char delim) {
_buffer = buf;
_len = len;
_delim = delim;
_cursor = 0;
}
bool next(TRAPS);
const char* key_addr() { return _key_addr; }
size_t key_length() { return _key_len; }
const char* value_addr() { return _value_addr; }
size_t value_length() { return _value_len; }
};
// A DCmdInfo instance provides a description of a diagnostic command. It is
// used to export the description to the JMX interface of the framework.
class DCmdInfo : public ResourceObj {
protected:
const char* _name;
const char* _description;
const char* _impact;
int _num_arguments;
bool _is_enabled;
public:
DCmdInfo(const char* name,
const char* description,
const char* impact,
int num_arguments,
bool enabled) {
this->_name = name;
this->_description = description;
this->_impact = impact;
this->_num_arguments = num_arguments;
this->_is_enabled = enabled;
}
const char* name() const { return _name; }
const char* description() const { return _description; }
const char* impact() const { return _impact; }
int num_arguments() const { return _num_arguments; }
bool is_enabled() const { return _is_enabled; }
static bool by_name(void* name, DCmdInfo* info);
};
// A DCmdArgumentInfo instance provides a description of a diagnostic command
// argument. It is used to export the description to the JMX interface of the
// framework.
class DCmdArgumentInfo : public ResourceObj {
protected:
const char* _name;
const char* _description;
const char* _type;
const char* _default_string;
bool _mandatory;
bool _option;
int _position;
public:
DCmdArgumentInfo(const char* name, const char* description, const char* type,
const char* default_string, bool mandatory, bool option) {
this->_name = name;
this->_description = description;
this->_type = type;
this->_default_string = default_string;
this->_option = option;
this->_mandatory = mandatory;
this->_option = option;
this->_position = -1;
}
DCmdArgumentInfo(const char* name, const char* description, const char* type,
const char* default_string, bool mandatory, bool option,
int position) {
this->_name = name;
this->_description = description;
this->_type = type;
this->_default_string = default_string;
this->_option = option;
this->_mandatory = mandatory;
this->_option = option;
this->_position = position;
}
const char* name() const { return _name; }
const char* description() const { return _description; }
const char* type() const { return _type; }
const char* default_string() const { return _default_string; }
bool is_mandatory() const { return _mandatory; }
bool is_option() const { return _option; }
int position() const { return _position; }
};
// The DCmdParser class can be used to create an argument parser for a
// diagnostic command. It is not mandatory to use it to parse arguments.
class DCmdParser {
private:
GenDCmdArgument* _options;
GenDCmdArgument* _arguments_list;
char _delim;
public:
DCmdParser() {
_options = NULL;
_arguments_list = NULL;
_delim = ' ';
}
void add_dcmd_option(GenDCmdArgument* arg);
void add_dcmd_argument(GenDCmdArgument* arg);
GenDCmdArgument* lookup_dcmd_option(const char* name, size_t len);
GenDCmdArgument* arguments_list() { return _arguments_list; };
void check(TRAPS);
void parse(CmdLine* line, char delim, TRAPS);
void print_help(outputStream* out, const char* cmd_name);
void reset(TRAPS);
void cleanup();
int num_arguments();
GrowableArray<const char*>* argument_name_array();
GrowableArray<DCmdArgumentInfo*>* argument_info_array();
};
// The DCmd class is the parent class of all diagnostic commands
// Diagnostic command instances should not be instantiated directly but
// created using the associated factory. The factory can be retrieved with
// the DCmdFactory::getFactory() method.
// A diagnostic command instance can either be allocated in the resource Area
// or in the C-heap. Allocation in the resource area is recommended when the
// current thread is the only one which will access the diagnostic command
// instance. Allocation in the C-heap is required when the diagnostic command
// is accessed by several threads (for instance to perform asynchronous
// execution).
// To ensure a proper cleanup, it's highly recommended to use a DCmdMark for
// each diagnostic command instance. In case of a C-heap allocated diagnostic
// command instance, the DCmdMark must be created in the context of the last
// thread that will access the instance.
class DCmd : public ResourceObj {
protected:
outputStream* _output;
bool _is_heap_allocated;
public:
DCmd(outputStream* output, bool heap_allocated) {
_output = output;
_is_heap_allocated = heap_allocated;
}
static const char* name() { return "No Name";}
static const char* description() { return "No Help";}
static const char* disabled_message() { return "Diagnostic command currently disabled"; }
// The impact() method returns a description of the intrusiveness of the diagnostic
// command on the Java Virtual Machine behavior. The rational for this method is that some
// diagnostic commands can seriously disrupt the behavior of the Java Virtual Machine
// (for instance a Thread Dump for an application with several tens of thousands of threads,
// or a Head Dump with a 40GB+ heap size) and other diagnostic commands have no serious
// impact on the JVM (for instance, getting the command line arguments or the JVM version).
// The recommended format for the description is <impact level>: [longer description],
// where the impact level is selected among this list: {Low, Medium, High}. The optional
// longer description can provide more specific details like the fact that Thread Dump
// impact depends on the heap size.
static const char* impact() { return "Low: No impact"; }
static int num_arguments() { return 0; }
outputStream* output() { return _output; }
bool is_heap_allocated() { return _is_heap_allocated; }
virtual void print_help(const char* name) {
output()->print_cr("Syntax: %s", name);
}
virtual void parse(CmdLine* line, char delim, TRAPS) {
DCmdArgIter iter(line->args_addr(), line->args_len(), delim);
bool has_arg = iter.next(CHECK);
if (has_arg) {
THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
"The argument list of this diagnostic command should be empty.");
}
}
virtual void execute(TRAPS) { }
virtual void reset(TRAPS) { }
virtual void cleanup() { }
// support for the JMX interface
virtual GrowableArray<const char*>* argument_name_array() {
GrowableArray<const char*>* array = new GrowableArray<const char*>(0);
return array;
}
virtual GrowableArray<DCmdArgumentInfo*>* argument_info_array() {
GrowableArray<DCmdArgumentInfo*>* array = new GrowableArray<DCmdArgumentInfo*>(0);
return array;
}
// main method to invoke the framework
static void parse_and_execute(outputStream* out, const char* cmdline,
char delim, TRAPS);
};
class DCmdWithParser : public DCmd {
protected:
DCmdParser _dcmdparser;
public:
DCmdWithParser (outputStream *output, bool heap=false) : DCmd(output, heap) { }
static const char* name() { return "No Name";}
static const char* description() { return "No Help";}
static const char* disabled_message() { return "Diagnostic command currently disabled"; }
static const char* impact() { return "Low: No impact"; }
static int num_arguments() { return 0; }
virtual void parse(CmdLine *line, char delim, TRAPS);
virtual void execute(TRAPS) { }
virtual void reset(TRAPS);
virtual void cleanup();
virtual void print_help(const char* name);
virtual GrowableArray<const char*>* argument_name_array();
virtual GrowableArray<DCmdArgumentInfo*>* argument_info_array();
};
class DCmdMark : public StackObj {
DCmd* _ref;
public:
DCmdMark(DCmd* cmd) { _ref = cmd; }
~DCmdMark() {
if (_ref != NULL) {
_ref->cleanup();
if (_ref->is_heap_allocated()) {
delete _ref;
}
}
}
};
// Diagnostic commands are not directly instantiated but created with a factory.
// Each diagnostic command class has its own factory. The DCmdFactory class also
// manages the status of the diagnostic command (hidden, enabled). A DCmdFactory
// has to be registered to make the diagnostic command available (see
// management.cpp)
class DCmdFactory: public CHeapObj<mtInternal> {
private:
static Mutex* _dcmdFactory_lock;
// Pointer to the next factory in the singly-linked list of registered
// diagnostic commands
DCmdFactory* _next;
// When disabled, a diagnostic command cannot be executed. Any attempt to
// execute it will result in the printing of the disabled message without
// instantiating the command.
bool _enabled;
// When hidden, a diagnostic command doesn't appear in the list of commands
// provided by the 'help' command.
bool _hidden;
int _num_arguments;
static DCmdFactory* _DCmdFactoryList;
public:
DCmdFactory(int num_arguments, bool enabled, bool hidden) {
_next = NULL;
_enabled = enabled;
_hidden = hidden;
_num_arguments = num_arguments;
}
bool is_enabled() const { return _enabled; }
void set_enabled(bool b) { _enabled = b; }
bool is_hidden() const { return _hidden; }
void set_hidden(bool b) { _hidden = b; }
int num_arguments() { return _num_arguments; }
DCmdFactory* next() { return _next; }
virtual DCmd* create_Cheap_instance(outputStream* output) = 0;
virtual DCmd* create_resource_instance(outputStream* output) = 0;
virtual const char* name() const = 0;
virtual const char* description() const = 0;
virtual const char* impact() const = 0;
virtual const char* disabled_message() const = 0;
// Register a DCmdFactory to make a diagnostic command available.
// Once registered, a diagnostic command must not be unregistered.
// To prevent a diagnostic command from being executed, just set the
// enabled flag to false.
static int register_DCmdFactory(DCmdFactory* factory);
static DCmdFactory* factory(const char* cmd, size_t len);
// Returns a C-heap allocated diagnostic command for the given command line
static DCmd* create_global_DCmd(CmdLine &line, outputStream* out, TRAPS);
// Returns a resourceArea allocated diagnostic command for the given command line
static DCmd* create_local_DCmd(CmdLine &line, outputStream* out, TRAPS);
static GrowableArray<const char*>* DCmd_list();
static GrowableArray<DCmdInfo*>* DCmdInfo_list();
friend class HelpDCmd;
};
// Template to easily create DCmdFactory instances. See management.cpp
// where this template is used to create and register factories.
template <class DCmdClass> class DCmdFactoryImpl : public DCmdFactory {
public:
DCmdFactoryImpl(bool enabled, bool hidden) :
DCmdFactory(DCmdClass::num_arguments(), enabled, hidden) { }
// Returns a C-heap allocated instance
virtual DCmd* create_Cheap_instance(outputStream* output) {
return new (ResourceObj::C_HEAP, mtInternal) DCmdClass(output, true);
}
// Returns a resourceArea allocated instance
virtual DCmd* create_resource_instance(outputStream* output) {
return new DCmdClass(output, false);
}
virtual const char* name() const {
return DCmdClass::name();
}
virtual const char* description() const {
return DCmdClass::description();
}
virtual const char* impact() const {
return DCmdClass::impact();
}
virtual const char* disabled_message() const {
return DCmdClass::disabled_message();
}
};
// This class provides a convenient way to register Dcmds, without a need to change
// management.cpp every time. Body of these two methods resides in
// diagnosticCommand.cpp
class DCmdRegistrant : public AllStatic {
private:
static void register_dcmds();
static void register_dcmds_ext();
friend class Management;
};
#endif // SHARE_VM_SERVICES_DIAGNOSTICFRAMEWORK_HPP