/*

 * 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