1 /*
   2  * Copyright (c) 2011, 2012, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_SERVICES_DIAGNOSTICFRAMEWORK_HPP
  26 #define SHARE_VM_SERVICES_DIAGNOSTICFRAMEWORK_HPP
  27 
  28 #include "classfile/vmSymbols.hpp"
  29 #include "memory/allocation.hpp"
  30 #include "runtime/arguments.hpp"
  31 #include "runtime/os.hpp"
  32 #include "runtime/vm_version.hpp"
  33 #include "runtime/vmThread.hpp"
  34 #include "utilities/ostream.hpp"
  35 
  36 
  37 enum DCmdSource {
  38   DCmd_Source_Internal  = 0x01U,  // invocation from the JVM
  39   DCmd_Source_AttachAPI = 0x02U,  // invocation via the attachAPI
  40   DCmd_Source_MBean     = 0x04U   // invocation via a MBean
  41 };
  42 
  43 // Warning: strings referenced by the JavaPermission struct are passed to
  44 // the native part of the JDK. Avoid use of dynamically allocated strings
  45 // that could be de-allocated before the JDK native code had time to
  46 // convert them into Java Strings.
  47 struct JavaPermission {
  48   const char* _class;
  49   const char* _name;
  50   const char* _action;
  51 };
  52 
  53 // CmdLine is the class used to handle a command line containing a single
  54 // diagnostic command and its arguments. It provides methods to access the
  55 // command name and the beginning of the arguments. The class is also
  56 // able to identify commented command lines and the "stop" keyword
  57 class CmdLine : public StackObj {
  58 private:
  59   const char* _cmd;
  60   size_t      _cmd_len;
  61   const char* _args;
  62   size_t      _args_len;
  63 public:
  64   CmdLine(const char* line, size_t len, bool no_command_name);
  65   const char* args_addr() const { return _args; }
  66   size_t args_len() const { return _args_len; }
  67   const char* cmd_addr() const { return _cmd; }
  68   size_t cmd_len() const { return _cmd_len; }
  69   bool is_empty() { return _cmd_len == 0; }
  70   bool is_executable() { return is_empty() || _cmd[0] != '#'; }
  71   bool is_stop() { return !is_empty() && strncmp("stop", _cmd, _cmd_len) == 0; }
  72 };
  73 
  74 // Iterator class taking a character string in input and returning a CmdLine
  75 // instance for each command line. The argument delimiter has to be specified.
  76 class DCmdIter : public StackObj {
  77   friend class DCmd;
  78 private:
  79   const char* _str;
  80   char        _delim;
  81   size_t      _len;
  82   size_t      _cursor;
  83 public:
  84 
  85   DCmdIter(const char* str, char delim) {
  86     _str = str;
  87     _delim = delim;
  88     _len = strlen(str);
  89     _cursor = 0;
  90   }
  91   bool has_next() { return _cursor < _len; }
  92   CmdLine next() {
  93     assert(_cursor <= _len, "Cannot iterate more");
  94     size_t n = _cursor;
  95     while (n < _len && _str[n] != _delim) n++;
  96     CmdLine line(&(_str[_cursor]), n - _cursor, false);
  97     _cursor = n + 1;
  98     // The default copy constructor of CmdLine is used to return a CmdLine
  99     // instance to the caller.
 100     return line;
 101   }
 102 };
 103 
 104 // Iterator class to iterate over diagnostic command arguments
 105 class DCmdArgIter : public ResourceObj {
 106   const char* _buffer;
 107   size_t      _len;
 108   size_t      _cursor;
 109   const char* _key_addr;
 110   size_t      _key_len;
 111   const char* _value_addr;
 112   size_t      _value_len;
 113   char        _delim;
 114 public:
 115   DCmdArgIter(const char* buf, size_t len, char delim) {
 116     _buffer = buf;
 117     _len = len;
 118     _delim = delim;
 119     _cursor = 0;
 120   }
 121   bool next(TRAPS);
 122   const char* key_addr() { return _key_addr; }
 123   size_t key_length() { return _key_len; }
 124   const char* value_addr() { return _value_addr; }
 125   size_t value_length() { return _value_len; }
 126 };
 127 
 128 // A DCmdInfo instance provides a description of a diagnostic command. It is
 129 // used to export the description to the JMX interface of the framework.
 130 class DCmdInfo : public ResourceObj {
 131 protected:
 132   const char* _name;           /* Name of the diagnostic command */
 133   const char* _description;    /* Short description */
 134   const char* _impact;         /* Impact on the JVM */
 135   JavaPermission _permission;  /* Java Permission required to execute this command if any */
 136   int         _num_arguments;  /* Number of supported options or arguments */
 137   bool        _is_enabled;     /* True if the diagnostic command can be invoked, false otherwise */
 138 public:
 139   DCmdInfo(const char* name,
 140           const char* description,
 141           const char* impact,
 142           JavaPermission permission,
 143           int num_arguments,
 144           bool enabled) {
 145     this->_name = name;
 146     this->_description = description;
 147     this->_impact = impact;
 148     this->_permission = permission;
 149     this->_num_arguments = num_arguments;
 150     this->_is_enabled = enabled;
 151   }
 152   const char* name() const { return _name; }
 153   const char* description() const { return _description; }
 154   const char* impact() const { return _impact; }
 155   JavaPermission permission() const { return _permission; }
 156   int num_arguments() const { return _num_arguments; }
 157   bool is_enabled() const { return _is_enabled; }
 158 
 159   static bool by_name(void* name, DCmdInfo* info);
 160 };
 161 
 162 // A DCmdArgumentInfo instance provides a description of a diagnostic command
 163 // argument. It is used to export the description to the JMX interface of the
 164 // framework.
 165 class DCmdArgumentInfo : public ResourceObj {
 166 protected:
 167   const char* _name;            /* Option/Argument name*/
 168   const char* _description;     /* Short description */
 169   const char* _type;            /* Type: STRING, BOOLEAN, etc. */
 170   const char* _default_string;  /* Default value in a parsable string */
 171   bool        _mandatory;       /* True if the option/argument is mandatory */
 172   bool        _option;          /* True if it is an option, false if it is an argument */
 173                                 /* (see diagnosticFramework.hpp for option/argument definitions) */
 174   bool        _multiple;        /* True is the option can be specified several time */
 175   int         _position;        /* Expected position for this argument (this field is */
 176                                 /* meaningless for options) */
 177 public:
 178   DCmdArgumentInfo(const char* name, const char* description, const char* type,
 179                    const char* default_string, bool mandatory, bool option,
 180                    bool multiple) {
 181     this->_name = name;
 182     this->_description = description;
 183     this->_type = type;
 184     this->_default_string = default_string;
 185     this->_option = option;
 186     this->_mandatory = mandatory;
 187     this->_option = option;
 188     this->_multiple = multiple;
 189     this->_position = -1;
 190   }
 191   DCmdArgumentInfo(const char* name, const char* description, const char* type,
 192                    const char* default_string, bool mandatory, bool option,
 193                    bool multiple, int position) {
 194     this->_name = name;
 195     this->_description = description;
 196     this->_type = type;
 197     this->_default_string = default_string;
 198     this->_option = option;
 199     this->_mandatory = mandatory;
 200     this->_option = option;
 201     this->_multiple = multiple;
 202     this->_position = position;
 203   }
 204   const char* name() const { return _name; }
 205   const char* description() const { return _description; }
 206   const char* type() const { return _type; }
 207   const char* default_string() const { return _default_string; }
 208   bool is_mandatory() const { return _mandatory; }
 209   bool is_option() const { return _option; }
 210   bool is_multiple() const { return _multiple; }
 211   int position() const { return _position; }
 212 };
 213 
 214 // The DCmdParser class can be used to create an argument parser for a
 215 // diagnostic command. It is not mandatory to use it to parse arguments.
 216 // The DCmdParser parse a CmdLine instance according to the parameters that
 217 // have been declared by its associated diagnostic command. A parameter can
 218 // either be an option or an argument. Options are identified by the option name
 219 // while arguments are identified by their position in the command line. The
 220 // position of an argument is defined relatively to all arguments passed on the
 221 // command line, options are not considered when defining an argument position.
 222 // The generic syntax of a diagnostic command is:
 223 //
 224 //    <command name> [<option>=<value>] [<argument_value>]
 225 //
 226 // Example:
 227 //
 228 //    command_name option1=value1 option2=value argumentA argumentB argumentC
 229 //
 230 // In this command line, the diagnostic command receives five parameters, two
 231 // options named option1 and option2, and three arguments. argumentA's position
 232 // is 0, argumentB's position is 1 and argumentC's position is 2.
 233 class DCmdParser {
 234 private:
 235   GenDCmdArgument* _options;
 236   GenDCmdArgument* _arguments_list;
 237   char             _delim;
 238 public:
 239   DCmdParser() {
 240     _options = NULL;
 241     _arguments_list = NULL;
 242     _delim = ' ';
 243   }
 244   void add_dcmd_option(GenDCmdArgument* arg);
 245   void add_dcmd_argument(GenDCmdArgument* arg);
 246   GenDCmdArgument* lookup_dcmd_option(const char* name, size_t len);
 247   GenDCmdArgument* arguments_list() { return _arguments_list; };
 248   void check(TRAPS);
 249   void parse(CmdLine* line, char delim, TRAPS);
 250   void print_help(outputStream* out, const char* cmd_name);
 251   void reset(TRAPS);
 252   void cleanup();
 253   int num_arguments();
 254   GrowableArray<const char*>* argument_name_array();
 255   GrowableArray<DCmdArgumentInfo*>* argument_info_array();
 256 };
 257 
 258 // The DCmd class is the parent class of all diagnostic commands
 259 // Diagnostic command instances should not be instantiated directly but
 260 // created using the associated factory. The factory can be retrieved with
 261 // the DCmdFactory::getFactory() method.
 262 // A diagnostic command instance can either be allocated in the resource Area
 263 // or in the C-heap. Allocation in the resource area is recommended when the
 264 // current thread is the only one which will access the diagnostic command
 265 // instance. Allocation in the C-heap is required when the diagnostic command
 266 // is accessed by several threads (for instance to perform asynchronous
 267 // execution).
 268 // To ensure a proper cleanup, it's highly recommended to use a DCmdMark for
 269 // each diagnostic command instance. In case of a C-heap allocated diagnostic
 270 // command instance, the DCmdMark must be created in the context of the last
 271 // thread that will access the instance.
 272 class DCmd : public ResourceObj {
 273 protected:
 274   outputStream* _output;
 275   bool          _is_heap_allocated;
 276 public:
 277   DCmd(outputStream* output, bool heap_allocated) {
 278     _output = output;
 279     _is_heap_allocated = heap_allocated;
 280   }
 281 
 282   static const char* name() { return "No Name";}
 283   static const char* description() { return "No Help";}
 284   static const char* disabled_message() { return "Diagnostic command currently disabled"; }
 285   // The impact() method returns a description of the intrusiveness of the diagnostic
 286   // command on the Java Virtual Machine behavior. The rational for this method is that some
 287   // diagnostic commands can seriously disrupt the behavior of the Java Virtual Machine
 288   // (for instance a Thread Dump for an application with several tens of thousands of threads,
 289   // or a Head Dump with a 40GB+ heap size) and other diagnostic commands have no serious
 290   // impact on the JVM (for instance, getting the command line arguments or the JVM version).
 291   // The recommended format for the description is <impact level>: [longer description],
 292   // where the impact level is selected among this list: {Low, Medium, High}. The optional
 293   // longer description can provide more specific details like the fact that Thread Dump
 294   // impact depends on the heap size.
 295   static const char* impact() { return "Low: No impact"; }
 296   static const JavaPermission permission() {JavaPermission p = {NULL, NULL, NULL}; return p; }
 297   static int num_arguments() { return 0; }
 298   outputStream* output() { return _output; }
 299   bool is_heap_allocated()  { return _is_heap_allocated; }
 300   virtual void print_help(const char* name) {
 301     output()->print_cr("Syntax: %s", name);
 302   }
 303   virtual void parse(CmdLine* line, char delim, TRAPS) {
 304     DCmdArgIter iter(line->args_addr(), line->args_len(), delim);
 305     bool has_arg = iter.next(CHECK);
 306     if (has_arg) {
 307       THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
 308                 "The argument list of this diagnostic command should be empty.");
 309     }
 310   }
 311   virtual void execute(DCmdSource source, TRAPS) { }
 312   virtual void reset(TRAPS) { }
 313   virtual void cleanup() { }
 314 
 315   // support for the JMX interface
 316   virtual GrowableArray<const char*>* argument_name_array() {
 317     GrowableArray<const char*>* array = new GrowableArray<const char*>(0);
 318     return array;
 319   }
 320   virtual GrowableArray<DCmdArgumentInfo*>* argument_info_array() {
 321     GrowableArray<DCmdArgumentInfo*>* array = new GrowableArray<DCmdArgumentInfo*>(0);
 322     return array;
 323   }
 324 
 325   // main method to invoke the framework
 326   static void parse_and_execute(DCmdSource source, outputStream* out, const char* cmdline,
 327                                 char delim, TRAPS);
 328 };
 329 
 330 class DCmdWithParser : public DCmd {
 331 protected:
 332   DCmdParser _dcmdparser;
 333 public:
 334   DCmdWithParser (outputStream *output, bool heap=false) : DCmd(output, heap) { }
 335   static const char* name() { return "No Name";}
 336   static const char* description() { return "No Help";}
 337   static const char* disabled_message() { return "Diagnostic command currently disabled"; }
 338   static const char* impact() { return "Low: No impact"; }
 339   static const JavaPermission permission() {JavaPermission p = {NULL, NULL, NULL}; return p; }
 340   static int num_arguments() { return 0; }
 341   virtual void parse(CmdLine *line, char delim, TRAPS);
 342   virtual void execute(DCmdSource source, TRAPS) { }
 343   virtual void reset(TRAPS);
 344   virtual void cleanup();
 345   virtual void print_help(const char* name);
 346   virtual GrowableArray<const char*>* argument_name_array();
 347   virtual GrowableArray<DCmdArgumentInfo*>* argument_info_array();
 348 };
 349 
 350 class DCmdMark : public StackObj {
 351   DCmd* _ref;
 352 public:
 353   DCmdMark(DCmd* cmd) { _ref = cmd; }
 354   ~DCmdMark() {
 355     if (_ref != NULL) {
 356       _ref->cleanup();
 357       if (_ref->is_heap_allocated()) {
 358         delete _ref;
 359       }
 360     }
 361   }
 362 };
 363 
 364 // Diagnostic commands are not directly instantiated but created with a factory.
 365 // Each diagnostic command class has its own factory. The DCmdFactory class also
 366 // manages the status of the diagnostic command (hidden, enabled). A DCmdFactory
 367 // has to be registered to make the diagnostic command available (see
 368 // management.cpp)
 369 class DCmdFactory: public CHeapObj<mtInternal> {
 370 private:
 371   static Mutex*       _dcmdFactory_lock;
 372   static bool         _send_jmx_notification;
 373   static bool         _has_pending_jmx_notification;
 374   // Pointer to the next factory in the singly-linked list of registered
 375   // diagnostic commands
 376   DCmdFactory*        _next;
 377   // When disabled, a diagnostic command cannot be executed. Any attempt to
 378   // execute it will result in the printing of the disabled message without
 379   // instantiating the command.
 380   bool                _enabled;
 381   // When hidden, a diagnostic command doesn't appear in the list of commands
 382   // provided by the 'help' command.
 383   bool                _hidden;
 384   uint32_t            _export_flags;
 385   int                 _num_arguments;
 386   static DCmdFactory* _DCmdFactoryList;
 387 public:
 388   DCmdFactory(int num_arguments, uint32_t flags, bool enabled, bool hidden) {
 389     _next = NULL;
 390     _enabled = enabled;
 391     _hidden = hidden;
 392     _export_flags = flags;
 393     _num_arguments = num_arguments;
 394   }
 395   bool is_enabled() const { return _enabled; }
 396   void set_enabled(bool b) { _enabled = b; }
 397   bool is_hidden() const { return _hidden; }
 398   void set_hidden(bool b) { _hidden = b; }
 399   uint32_t export_flags() { return _export_flags; }
 400   void set_export_flags(uint32_t f) { _export_flags = f; }
 401   int num_arguments() { return _num_arguments; }
 402   DCmdFactory* next() { return _next; }
 403   virtual DCmd* create_Cheap_instance(outputStream* output) = 0;
 404   virtual DCmd* create_resource_instance(outputStream* output) = 0;
 405   virtual const char* name() const = 0;
 406   virtual const char* description() const = 0;
 407   virtual const char* impact() const = 0;
 408   virtual const JavaPermission permission() const = 0;
 409   virtual const char* disabled_message() const = 0;
 410   // Register a DCmdFactory to make a diagnostic command available.
 411   // Once registered, a diagnostic command must not be unregistered.
 412   // To prevent a diagnostic command from being executed, just set the
 413   // enabled flag to false.
 414   static int register_DCmdFactory(DCmdFactory* factory);
 415   static DCmdFactory* factory(DCmdSource source, const char* cmd, size_t len);
 416   // Returns a C-heap allocated diagnostic command for the given command line
 417   static DCmd* create_global_DCmd(DCmdSource source, CmdLine &line, outputStream* out, TRAPS);
 418   // Returns a resourceArea allocated diagnostic command for the given command line
 419   static DCmd* create_local_DCmd(DCmdSource source, CmdLine &line, outputStream* out, TRAPS);
 420   static GrowableArray<const char*>* DCmd_list(DCmdSource source);
 421   static GrowableArray<DCmdInfo*>* DCmdInfo_list(DCmdSource source);
 422 
 423   static void set_jmx_notification_enabled(bool enabled) {
 424     _send_jmx_notification = enabled;
 425   }
 426   static void push_jmx_notification_request();
 427   static bool has_pending_jmx_notification() { return _has_pending_jmx_notification; }
 428   static void send_notification(TRAPS);
 429 private:
 430   static void send_notification_internal(TRAPS);
 431   
 432   friend class HelpDCmd;
 433 };
 434 
 435 // Template to easily create DCmdFactory instances. See management.cpp
 436 // where this template is used to create and register factories.
 437 template <class DCmdClass> class DCmdFactoryImpl : public DCmdFactory {
 438 public:
 439   DCmdFactoryImpl(uint32_t flags, bool enabled, bool hidden) :
 440     DCmdFactory(DCmdClass::num_arguments(), flags, enabled, hidden) { }
 441   // Returns a C-heap allocated instance
 442   virtual DCmd* create_Cheap_instance(outputStream* output) {
 443     return new (ResourceObj::C_HEAP, mtInternal) DCmdClass(output, true);
 444   }
 445   // Returns a resourceArea allocated instance
 446   virtual DCmd* create_resource_instance(outputStream* output) {
 447     return new DCmdClass(output, false);
 448   }
 449   virtual const char* name() const {
 450     return DCmdClass::name();
 451   }
 452   virtual const char* description() const {
 453     return DCmdClass::description();
 454   }
 455   virtual const char* impact() const {
 456     return DCmdClass::impact();
 457   }
 458   virtual const JavaPermission permission() const {
 459     return DCmdClass::permission();
 460   }
 461   virtual const char* disabled_message() const {
 462      return DCmdClass::disabled_message();
 463   }
 464 };
 465 
 466 // This class provides a convenient way to register Dcmds, without a need to change
 467 // management.cpp every time. Body of these two methods resides in
 468 // diagnosticCommand.cpp
 469 
 470 class DCmdRegistrant : public AllStatic {
 471 
 472 private:
 473     static void register_dcmds();
 474     static void register_dcmds_ext();
 475 
 476     friend class Management;
 477 };
 478 
 479 #endif // SHARE_VM_SERVICES_DIAGNOSTICFRAMEWORK_HPP