1 /* 2 * Copyright (c) 2011, 2014, 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/vmThread.hpp" 33 #include "utilities/ostream.hpp" 34 35 36 enum DCmdSource { 37 DCmd_Source_Internal = 0x01U, // invocation from the JVM 38 DCmd_Source_AttachAPI = 0x02U, // invocation via the attachAPI 39 DCmd_Source_MBean = 0x04U // invocation via a MBean 40 }; 41 42 // Warning: strings referenced by the JavaPermission struct are passed to 43 // the native part of the JDK. Avoid use of dynamically allocated strings 44 // that could be de-allocated before the JDK native code had time to 45 // convert them into Java Strings. 46 struct JavaPermission { 47 const char* _class; 48 const char* _name; 49 const char* _action; 50 }; 51 52 // CmdLine is the class used to handle a command line containing a single 53 // diagnostic command and its arguments. It provides methods to access the 54 // command name and the beginning of the arguments. The class is also 55 // able to identify commented command lines and the "stop" keyword 56 class CmdLine : public StackObj { 57 private: 58 const char* _cmd; 59 size_t _cmd_len; 60 const char* _args; 61 size_t _args_len; 62 public: 63 CmdLine(const char* line, size_t len, bool no_command_name); 64 const char* args_addr() const { return _args; } 65 size_t args_len() const { return _args_len; } 66 const char* cmd_addr() const { return _cmd; } 67 size_t cmd_len() const { return _cmd_len; } 68 bool is_empty() const { return _cmd_len == 0; } 69 bool is_executable() const { return is_empty() || _cmd[0] != '#'; } 70 bool is_stop() const { return !is_empty() && strncmp("stop", _cmd, _cmd_len) == 0; } 71 }; 72 73 // Iterator class taking a character string in input and returning a CmdLine 74 // instance for each command line. The argument delimiter has to be specified. 75 class DCmdIter : public StackObj { 76 friend class DCmd; 77 private: 78 const char* const _str; 79 const char _delim; 80 const size_t _len; 81 size_t _cursor; 82 public: 83 84 DCmdIter(const char* str, char delim) 85 : _str(str) 86 , _delim(delim) 87 , _len(::strlen(str)) 88 , _cursor(0) {} 89 bool has_next() const { return _cursor < _len; } 90 CmdLine next() { 91 assert(_cursor <= _len, "Cannot iterate more"); 92 size_t n = _cursor; 93 while (n < _len && _str[n] != _delim) n++; 94 CmdLine line(&(_str[_cursor]), n - _cursor, false); 95 _cursor = n + 1; 96 // The default copy constructor of CmdLine is used to return a CmdLine 97 // instance to the caller. 98 return line; 99 } 100 }; 101 102 // Iterator class to iterate over diagnostic command arguments 103 class DCmdArgIter : public ResourceObj { 104 const char* const _buffer; 105 const size_t _len; 106 size_t _cursor; 107 const char* _key_addr; 108 size_t _key_len; 109 const char* _value_addr; 110 size_t _value_len; 111 const char _delim; 112 public: 113 DCmdArgIter(const char* buf, size_t len, char delim) 114 : _buffer(buf) 115 , _len(len) 116 , _cursor(0) 117 , _key_addr(NULL) 118 , _key_len(0) 119 , _value_addr(NULL) 120 , _value_len(0) 121 , _delim(delim) 122 {} 123 124 bool next(TRAPS); 125 const char* key_addr() const { return _key_addr; } 126 size_t key_length() const { return _key_len; } 127 const char* value_addr() const { return _value_addr; } 128 size_t value_length() const { return _value_len; } 129 }; 130 131 // A DCmdInfo instance provides a description of a diagnostic command. It is 132 // used to export the description to the JMX interface of the framework. 133 class DCmdInfo : public ResourceObj { 134 protected: 135 const char* const _name; /* Name of the diagnostic command */ 136 const char* const _description; /* Short description */ 137 const char* const _impact; /* Impact on the JVM */ 138 const JavaPermission _permission; /* Java Permission required to execute this command if any */ 139 const int _num_arguments; /* Number of supported options or arguments */ 140 const bool _is_enabled; /* True if the diagnostic command can be invoked, false otherwise */ 141 public: 142 DCmdInfo(const char* name, 143 const char* description, 144 const char* impact, 145 JavaPermission permission, 146 int num_arguments, 147 bool enabled) 148 : _name(name) 149 , _description(description) 150 , _impact(impact) 151 , _permission(permission) 152 , _num_arguments(num_arguments) 153 , _is_enabled(enabled) {} 154 const char* name() const { return _name; } 155 const char* description() const { return _description; } 156 const char* impact() const { return _impact; } 157 const JavaPermission& permission() const { return _permission; } 158 int num_arguments() const { return _num_arguments; } 159 bool is_enabled() const { return _is_enabled; } 160 161 static bool by_name(void* name, DCmdInfo* info); 162 }; 163 164 // A DCmdArgumentInfo instance provides a description of a diagnostic command 165 // argument. It is used to export the description to the JMX interface of the 166 // framework. 167 class DCmdArgumentInfo : public ResourceObj { 168 protected: 169 const char* const _name; /* Option/Argument name*/ 170 const char* const _description; /* Short description */ 171 const char* const _type; /* Type: STRING, BOOLEAN, etc. */ 172 const char* const _default_string; /* Default value in a parsable string */ 173 const bool _mandatory; /* True if the option/argument is mandatory */ 174 const bool _option; /* True if it is an option, false if it is an argument */ 175 /* (see diagnosticFramework.hpp for option/argument definitions) */ 176 const bool _multiple; /* True is the option can be specified several time */ 177 const int _position; /* Expected position for this argument (this field is */ 178 /* meaningless for options) */ 179 public: 180 DCmdArgumentInfo(const char* name, const char* description, const char* type, 181 const char* default_string, bool mandatory, bool option, 182 bool multiple, int position = -1) 183 : _name(name) 184 , _description(description) 185 , _type(type) 186 , _default_string(default_string) 187 , _mandatory(mandatory) 188 , _option(option) 189 , _multiple(multiple) 190 , _position(position) {} 191 192 const char* name() const { return _name; } 193 const char* description() const { return _description; } 194 const char* type() const { return _type; } 195 const char* default_string() const { return _default_string; } 196 bool is_mandatory() const { return _mandatory; } 197 bool is_option() const { return _option; } 198 bool is_multiple() const { return _multiple; } 199 int position() const { return _position; } 200 }; 201 202 // The DCmdParser class can be used to create an argument parser for a 203 // diagnostic command. It is not mandatory to use it to parse arguments. 204 // The DCmdParser parses a CmdLine instance according to the parameters that 205 // have been declared by its associated diagnostic command. A parameter can 206 // either be an option or an argument. Options are identified by the option name 207 // while arguments are identified by their position in the command line. The 208 // position of an argument is defined relative to all arguments passed on the 209 // command line, options are not considered when defining an argument position. 210 // The generic syntax of a diagnostic command is: 211 // 212 // <command name> [<option>=<value>] [<argument_value>] 213 // 214 // Example: 215 // 216 // command_name option1=value1 option2=value argumentA argumentB argumentC 217 // 218 // In this command line, the diagnostic command receives five parameters, two 219 // options named option1 and option2, and three arguments. argumentA's position 220 // is 0, argumentB's position is 1 and argumentC's position is 2. 221 class DCmdParser { 222 private: 223 GenDCmdArgument* _options; 224 GenDCmdArgument* _arguments_list; 225 public: 226 DCmdParser() 227 : _options(NULL) 228 , _arguments_list(NULL) {} 229 void add_dcmd_option(GenDCmdArgument* arg); 230 void add_dcmd_argument(GenDCmdArgument* arg); 231 GenDCmdArgument* lookup_dcmd_option(const char* name, size_t len); 232 GenDCmdArgument* arguments_list() const { return _arguments_list; }; 233 void check(TRAPS); 234 void parse(CmdLine* line, char delim, TRAPS); 235 void print_help(outputStream* out, const char* cmd_name) const; 236 void reset(TRAPS); 237 void cleanup(); 238 int num_arguments() const; 239 GrowableArray<const char*>* argument_name_array() const; 240 GrowableArray<DCmdArgumentInfo*>* argument_info_array() const; 241 }; 242 243 // The DCmd class is the parent class of all diagnostic commands 244 // Diagnostic command instances should not be instantiated directly but 245 // created using the associated factory. The factory can be retrieved with 246 // the DCmdFactory::getFactory() method. 247 // A diagnostic command instance can either be allocated in the resource Area 248 // or in the C-heap. Allocation in the resource area is recommended when the 249 // current thread is the only one which will access the diagnostic command 250 // instance. Allocation in the C-heap is required when the diagnostic command 251 // is accessed by several threads (for instance to perform asynchronous 252 // execution). 253 // To ensure a proper cleanup, it's highly recommended to use a DCmdMark for 254 // each diagnostic command instance. In case of a C-heap allocated diagnostic 255 // command instance, the DCmdMark must be created in the context of the last 256 // thread that will access the instance. 257 class DCmd : public ResourceObj { 258 protected: 259 outputStream* const _output; 260 const bool _is_heap_allocated; 261 public: 262 DCmd(outputStream* output, bool heap_allocated) 263 : _output(output) 264 , _is_heap_allocated(heap_allocated) {} 265 266 // Child classes: please always provide these methods: 267 // static const char* name() { return "<command name>";} 268 // static const char* description() { return "<command help>";} 269 270 static const char* disabled_message() { return "Diagnostic command currently disabled"; } 271 272 // The impact() method returns a description of the intrusiveness of the diagnostic 273 // command on the Java Virtual Machine behavior. The rational for this method is that some 274 // diagnostic commands can seriously disrupt the behavior of the Java Virtual Machine 275 // (for instance a Thread Dump for an application with several tens of thousands of threads, 276 // or a Head Dump with a 40GB+ heap size) and other diagnostic commands have no serious 277 // impact on the JVM (for instance, getting the command line arguments or the JVM version). 278 // The recommended format for the description is <impact level>: [longer description], 279 // where the impact level is selected among this list: {Low, Medium, High}. The optional 280 // longer description can provide more specific details like the fact that Thread Dump 281 // impact depends on the heap size. 282 static const char* impact() { return "Low: No impact"; } 283 284 // The permission() method returns the description of Java Permission. This 285 // permission is required when the diagnostic command is invoked via the 286 // DiagnosticCommandMBean. The rationale for this permission check is that 287 // the DiagnosticCommandMBean can be used to perform remote invocations of 288 // diagnostic commands through the PlatformMBeanServer. The (optional) Java 289 // Permission associated with each diagnostic command should ease the work 290 // of system administrators to write policy files granting permissions to 291 // execute diagnostic commands to remote users. Any diagnostic command with 292 // a potential impact on security should overwrite this method. 293 static const JavaPermission permission() { 294 JavaPermission p = {NULL, NULL, NULL}; 295 return p; 296 } 297 static int num_arguments() { return 0; } 298 outputStream* output() const { return _output; } 299 bool is_heap_allocated() const { return _is_heap_allocated; } 300 virtual void print_help(const char* name) const { 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() const { 317 GrowableArray<const char*>* array = new GrowableArray<const char*>(0); 318 return array; 319 } 320 virtual GrowableArray<DCmdArgumentInfo*>* argument_info_array() const { 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* disabled_message() { return "Diagnostic command currently disabled"; } 336 static const char* impact() { return "Low: No impact"; } 337 virtual void parse(CmdLine *line, char delim, TRAPS); 338 virtual void execute(DCmdSource source, TRAPS) { } 339 virtual void reset(TRAPS); 340 virtual void cleanup(); 341 virtual void print_help(const char* name) const; 342 virtual GrowableArray<const char*>* argument_name_array() const; 343 virtual GrowableArray<DCmdArgumentInfo*>* argument_info_array() const; 344 }; 345 346 class DCmdMark : public StackObj { 347 DCmd* const _ref; 348 public: 349 DCmdMark(DCmd* cmd) : _ref(cmd) {} 350 ~DCmdMark() { 351 if (_ref != NULL) { 352 _ref->cleanup(); 353 if (_ref->is_heap_allocated()) { 354 delete _ref; 355 } 356 } 357 } 358 }; 359 360 // Diagnostic commands are not directly instantiated but created with a factory. 361 // Each diagnostic command class has its own factory. The DCmdFactory class also 362 // manages the status of the diagnostic command (hidden, enabled). A DCmdFactory 363 // has to be registered to make the diagnostic command available (see 364 // management.cpp) 365 class DCmdFactory: public CHeapObj<mtInternal> { 366 private: 367 static Mutex* _dcmdFactory_lock; 368 static bool _send_jmx_notification; 369 static bool _has_pending_jmx_notification; 370 static DCmdFactory* _DCmdFactoryList; 371 372 // Pointer to the next factory in the singly-linked list of registered 373 // diagnostic commands 374 DCmdFactory* _next; 375 // When disabled, a diagnostic command cannot be executed. Any attempt to 376 // execute it will result in the printing of the disabled message without 377 // instantiating the command. 378 const bool _enabled; 379 // When hidden, a diagnostic command doesn't appear in the list of commands 380 // provided by the 'help' command. 381 const bool _hidden; 382 const uint32_t _export_flags; 383 const int _num_arguments; 384 385 public: 386 DCmdFactory(int num_arguments, uint32_t flags, bool enabled, bool hidden) 387 : _next(NULL) 388 , _enabled(enabled) 389 , _hidden(hidden) 390 , _export_flags(flags) 391 , _num_arguments(num_arguments) {} 392 bool is_enabled() const { return _enabled; } 393 bool is_hidden() const { return _hidden; } 394 uint32_t export_flags() const { return _export_flags; } 395 int num_arguments() const { return _num_arguments; } 396 DCmdFactory* next() const { return _next; } 397 virtual DCmd* create_resource_instance(outputStream* output) const = 0; 398 virtual const char* name() const = 0; 399 virtual const char* description() const = 0; 400 virtual const char* impact() const = 0; 401 virtual const JavaPermission permission() const = 0; 402 virtual const char* disabled_message() const = 0; 403 // Register a DCmdFactory to make a diagnostic command available. 404 // Once registered, a diagnostic command must not be unregistered. 405 // To prevent a diagnostic command from being executed, just set the 406 // enabled flag to false. 407 static int register_DCmdFactory(DCmdFactory* factory); 408 static DCmdFactory* factory(DCmdSource source, const char* cmd, size_t len); 409 // Returns a resourceArea allocated diagnostic command for the given command line 410 static DCmd* create_local_DCmd(DCmdSource source, CmdLine &line, outputStream* out, TRAPS); 411 static GrowableArray<const char*>* DCmd_list(DCmdSource source); 412 static GrowableArray<DCmdInfo*>* DCmdInfo_list(DCmdSource source); 413 414 static void set_jmx_notification_enabled(bool enabled) { 415 _send_jmx_notification = enabled; 416 } 417 static void push_jmx_notification_request(); 418 static bool has_pending_jmx_notification() { return _has_pending_jmx_notification; } 419 static void send_notification(TRAPS); 420 private: 421 static void send_notification_internal(TRAPS); 422 423 friend class HelpDCmd; 424 }; 425 426 // Template to easily create DCmdFactory instances. See management.cpp 427 // where this template is used to create and register factories. 428 template <class DCmdClass> class DCmdFactoryImpl : public DCmdFactory { 429 public: 430 DCmdFactoryImpl(uint32_t flags, bool enabled, bool hidden) : 431 DCmdFactory(DCmdClass::num_arguments(), flags, enabled, hidden) { } 432 // Returns a resourceArea allocated instance 433 DCmd* create_resource_instance(outputStream* output) const { 434 return new DCmdClass(output, false); 435 } 436 const char* name() const { 437 return DCmdClass::name(); 438 } 439 const char* description() const { 440 return DCmdClass::description(); 441 } 442 const char* impact() const { 443 return DCmdClass::impact(); 444 } 445 const JavaPermission permission() const { 446 return DCmdClass::permission(); 447 } 448 const char* disabled_message() const { 449 return DCmdClass::disabled_message(); 450 } 451 }; 452 453 // This class provides a convenient way to register Dcmds, without a need to change 454 // management.cpp every time. Body of these two methods resides in 455 // diagnosticCommand.cpp 456 457 class DCmdRegistrant : public AllStatic { 458 459 private: 460 static void register_dcmds(); 461 static void register_dcmds_ext(); 462 463 friend class Management; 464 }; 465 466 #endif // SHARE_VM_SERVICES_DIAGNOSTICFRAMEWORK_HPP