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 /*

  * Copyright (c) 2011, 2013, 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"

 enum DCmdSource {

   DCmd_Source_Internal  = 0x01U,  // invocation from the JVM

   DCmd_Source_AttachAPI = 0x02U,  // invocation via the attachAPI

   DCmd_Source_MBean     = 0x04U   // invocation via a MBean

 };

 // Warning: strings referenced by the JavaPermission struct are passed to

 // the native part of the JDK. Avoid use of dynamically allocated strings

 // that could be de-allocated before the JDK native code had time to

 // convert them into Java Strings.

 struct JavaPermission {

   const char* _class;

   const char* _name;

   const char* _action;

 };

 // 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;           /* Name of the diagnostic command */

   const char* _description;    /* Short description */

   const char* _impact;         /* Impact on the JVM */

   JavaPermission _permission;  /* Java Permission required to execute this command if any */

   int         _num_arguments;  /* Number of supported options or arguments */

   bool        _is_enabled;     /* True if the diagnostic command can be invoked, false otherwise */

 public:

   DCmdInfo(const char* name,

           const char* description,

           const char* impact,

           JavaPermission permission,

           int num_arguments,

           bool enabled) {

     this->_name = name;

     this->_description = description;

     this->_impact = impact;

     this->_permission = permission;

     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; }

   JavaPermission permission() const { return _permission; }

   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;            /* Option/Argument name*/

   const char* _description;     /* Short description */

   const char* _type;            /* Type: STRING, BOOLEAN, etc. */

   const char* _default_string;  /* Default value in a parsable string */

   bool        _mandatory;       /* True if the option/argument is mandatory */

   bool        _option;          /* True if it is an option, false if it is an argument */

                                 /* (see diagnosticFramework.hpp for option/argument definitions) */

   bool        _multiple;        /* True is the option can be specified several time */

   int         _position;        /* Expected position for this argument (this field is */

                                 /* meaningless for options) */

 public:

   DCmdArgumentInfo(const char* name, const char* description, const char* type,

                    const char* default_string, bool mandatory, bool option,

                    bool multiple) {

     this->_name = name;

     this->_description = description;

     this->_type = type;

     this->_default_string = default_string;

     this->_option = option;

     this->_mandatory = mandatory;

     this->_option = option;

     this->_multiple = multiple;

     this->_position = -1;

   }

   DCmdArgumentInfo(const char* name, const char* description, const char* type,

                    const char* default_string, bool mandatory, bool option,

                    bool multiple, 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->_multiple = multiple;

     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; }

   bool is_multiple() const { return _multiple; }

   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.

 // The DCmdParser parses a CmdLine instance according to the parameters that

 // have been declared by its associated diagnostic command. A parameter can

 // either be an option or an argument. Options are identified by the option name

 // while arguments are identified by their position in the command line. The

 // position of an argument is defined relative to all arguments passed on the

 // command line, options are not considered when defining an argument position.

 // The generic syntax of a diagnostic command is:

 //

 //    <command name> [<option>=<value>] [<argument_value>]

 //

 // Example:

 //

 //    command_name option1=value1 option2=value argumentA argumentB argumentC

 //

 // In this command line, the diagnostic command receives five parameters, two

 // options named option1 and option2, and three arguments. argumentA's position

 // is 0, argumentB's position is 1 and argumentC's position is 2.

 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"; }

   // The permission() method returns the description of Java Permission. This

   // permission is required when the diagnostic command is invoked via the

   // DiagnosticCommandMBean. The rationale for this permission check is that

   // the DiagnosticCommandMBean can be used to perform remote invocations of

   // diagnostic commands through the PlatformMBeanServer. The (optional) Java

   // Permission associated with each diagnostic command should ease the work

   // of system administrators to write policy files granting permissions to

   // execute diagnostic commands to remote users. Any diagnostic command with

   // a potential impact on security should overwrite this method.

   static const JavaPermission permission() {

     JavaPermission p = {NULL, NULL, NULL};

     return p;

   }

   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(DCmdSource source, 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(DCmdSource source, 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 const JavaPermission permission() {JavaPermission p = {NULL, NULL, NULL}; return p; }

   static int num_arguments() { return 0; }

   virtual void parse(CmdLine *line, char delim, TRAPS);

   virtual void execute(DCmdSource source, 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;

   static bool         _send_jmx_notification;

   static bool         _has_pending_jmx_notification;

   // 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;

   uint32_t            _export_flags;

   int                 _num_arguments;

   static DCmdFactory* _DCmdFactoryList;

 public:

   DCmdFactory(int num_arguments, uint32_t flags, bool enabled, bool hidden) {

     _next = NULL;

     _enabled = enabled;

     _hidden = hidden;

     _export_flags = flags;

     _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; }

   uint32_t export_flags() { return _export_flags; }

   void set_export_flags(uint32_t f) { _export_flags = f; }

   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 JavaPermission permission() 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(DCmdSource source, const char* cmd, size_t len);

   // Returns a C-heap allocated diagnostic command for the given command line

   static DCmd* create_global_DCmd(DCmdSource source, CmdLine &line, outputStream* out, TRAPS);

   // Returns a resourceArea allocated diagnostic command for the given command line

   static DCmd* create_local_DCmd(DCmdSource source, CmdLine &line, outputStream* out, TRAPS);

   static GrowableArray<const char*>* DCmd_list(DCmdSource source);

   static GrowableArray<DCmdInfo*>* DCmdInfo_list(DCmdSource source);

   static void set_jmx_notification_enabled(bool enabled) {

     _send_jmx_notification = enabled;

   }

   static void push_jmx_notification_request();

   static bool has_pending_jmx_notification() { return _has_pending_jmx_notification; }

   static void send_notification(TRAPS);

 private:

   static void send_notification_internal(TRAPS);

   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(uint32_t flags, bool enabled, bool hidden) :

     DCmdFactory(DCmdClass::num_arguments(), flags, 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 JavaPermission permission() const {

     return DCmdClass::permission();

   }

   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