1 /* 2 * Copyright (c) 2011, 2018, 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), _delim(delim), _len(::strlen(str)), 86 _cursor(0) {} 87 bool has_next() const { return _cursor < _len; } 88 CmdLine next() { 89 assert(_cursor <= _len, "Cannot iterate more"); 90 size_t n = _cursor; 91 while (n < _len && _str[n] != _delim) n++; 92 CmdLine line(&(_str[_cursor]), n - _cursor, false); 93 _cursor = n + 1; 94 // The default copy constructor of CmdLine is used to return a CmdLine 95 // instance to the caller. 96 return line; 97 } 98 }; 99 100 // Iterator class to iterate over diagnostic command arguments 101 class DCmdArgIter : public ResourceObj { 102 const char* const _buffer; 103 const size_t _len; 104 size_t _cursor; 105 const char* _key_addr; 106 size_t _key_len; 107 const char* _value_addr; 108 size_t _value_len; 109 const char _delim; 110 public: 111 DCmdArgIter(const char* buf, size_t len, char delim) 112 : _buffer(buf), _len(len), _cursor(0), _key_addr(NULL), 113 _key_len(0), _value_addr(NULL), _value_len(0), _delim(delim) {} 114 115 bool next(TRAPS); 116 const char* key_addr() const { return _key_addr; } 117 size_t key_length() const { return _key_len; } 118 const char* value_addr() const { return _value_addr; } 119 size_t value_length() const { return _value_len; } 120 }; 121 122 // A DCmdInfo instance provides a description of a diagnostic command. It is 123 // used to export the description to the JMX interface of the framework. 124 class DCmdInfo : public ResourceObj { 125 protected: 126 const char* const _name; /* Name of the diagnostic command */ 127 const char* const _description; /* Short description */ 128 const char* const _impact; /* Impact on the JVM */ 129 const JavaPermission _permission; /* Java Permission required to execute this command if any */ 130 const int _num_arguments; /* Number of supported options or arguments */ 131 const bool _is_enabled; /* True if the diagnostic command can be invoked, false otherwise */ 132 public: 133 DCmdInfo(const char* name, 134 const char* description, 135 const char* impact, 136 JavaPermission permission, 137 int num_arguments, 138 bool enabled) 139 : _name(name), _description(description), _impact(impact), _permission(permission), 140 _num_arguments(num_arguments), _is_enabled(enabled) {} 141 const char* name() const { return _name; } 142 const char* description() const { return _description; } 143 const char* impact() const { return _impact; } 144 const JavaPermission& permission() const { return _permission; } 145 int num_arguments() const { return _num_arguments; } 146 bool is_enabled() const { return _is_enabled; } 147 148 static bool by_name(void* name, DCmdInfo* info); 149 }; 150 151 // A DCmdArgumentInfo instance provides a description of a diagnostic command 152 // argument. It is used to export the description to the JMX interface of the 153 // framework. 154 class DCmdArgumentInfo : public ResourceObj { 155 protected: 156 const char* const _name; /* Option/Argument name*/ 157 const char* const _description; /* Short description */ 158 const char* const _type; /* Type: STRING, BOOLEAN, etc. */ 159 const char* const _default_string; /* Default value in a parsable string */ 160 const bool _mandatory; /* True if the option/argument is mandatory */ 161 const bool _option; /* True if it is an option, false if it is an argument */ 162 /* (see diagnosticFramework.hpp for option/argument definitions) */ 163 const bool _multiple; /* True is the option can be specified several time */ 164 const int _position; /* Expected position for this argument (this field is */ 165 /* meaningless for options) */ 166 public: 167 DCmdArgumentInfo(const char* name, const char* description, const char* type, 168 const char* default_string, bool mandatory, bool option, 169 bool multiple, int position = -1) 170 : _name(name), _description(description), _type(type), 171 _default_string(default_string), _mandatory(mandatory), _option(option), 172 _multiple(multiple), _position(position) {} 173 174 const char* name() const { return _name; } 175 const char* description() const { return _description; } 176 const char* type() const { return _type; } 177 const char* default_string() const { return _default_string; } 178 bool is_mandatory() const { return _mandatory; } 179 bool is_option() const { return _option; } 180 bool is_multiple() const { return _multiple; } 181 int position() const { return _position; } 182 }; 183 184 // The DCmdParser class can be used to create an argument parser for a 185 // diagnostic command. It is not mandatory to use it to parse arguments. 186 // The DCmdParser parses a CmdLine instance according to the parameters that 187 // have been declared by its associated diagnostic command. A parameter can 188 // either be an option or an argument. Options are identified by the option name 189 // while arguments are identified by their position in the command line. The 190 // position of an argument is defined relative to all arguments passed on the 191 // command line, options are not considered when defining an argument position. 192 // The generic syntax of a diagnostic command is: 193 // 194 // <command name> [<option>=<value>] [<argument_value>] 195 // 196 // Example: 197 // 198 // command_name option1=value1 option2=value argumentA argumentB argumentC 199 // 200 // In this command line, the diagnostic command receives five parameters, two 201 // options named option1 and option2, and three arguments. argumentA's position 202 // is 0, argumentB's position is 1 and argumentC's position is 2. 203 class DCmdParser { 204 private: 205 GenDCmdArgument* _options; 206 GenDCmdArgument* _arguments_list; 207 public: 208 DCmdParser() 209 : _options(NULL), _arguments_list(NULL) {} 210 void add_dcmd_option(GenDCmdArgument* arg); 211 void add_dcmd_argument(GenDCmdArgument* arg); 212 GenDCmdArgument* lookup_dcmd_option(const char* name, size_t len); 213 GenDCmdArgument* arguments_list() const { return _arguments_list; }; 214 void check(TRAPS); 215 void parse(CmdLine* line, char delim, TRAPS); 216 void print_help(outputStream* out, const char* cmd_name) const; 217 void reset(TRAPS); 218 void cleanup(); 219 int num_arguments() const; 220 GrowableArray<const char*>* argument_name_array() const; 221 GrowableArray<DCmdArgumentInfo*>* argument_info_array() const; 222 }; 223 224 // The DCmd class is the parent class of all diagnostic commands 225 // Diagnostic command instances should not be instantiated directly but 226 // created using the associated factory. The factory can be retrieved with 227 // the DCmdFactory::getFactory() method. 228 // A diagnostic command instance can either be allocated in the resource Area 229 // or in the C-heap. Allocation in the resource area is recommended when the 230 // current thread is the only one which will access the diagnostic command 231 // instance. Allocation in the C-heap is required when the diagnostic command 232 // is accessed by several threads (for instance to perform asynchronous 233 // execution). 234 // To ensure a proper cleanup, it's highly recommended to use a DCmdMark for 235 // each diagnostic command instance. In case of a C-heap allocated diagnostic 236 // command instance, the DCmdMark must be created in the context of the last 237 // thread that will access the instance. 238 class DCmd : public ResourceObj { 239 protected: 240 outputStream* const _output; 241 const bool _is_heap_allocated; 242 public: 243 DCmd(outputStream* output, bool heap_allocated) 244 : _output(output), _is_heap_allocated(heap_allocated) {} 245 246 // Child classes: please always provide these methods: 247 // static const char* name() { return "<command name>";} 248 // static const char* description() { return "<command help>";} 249 250 static const char* disabled_message() { return "Diagnostic command currently disabled"; } 251 252 // The impact() method returns a description of the intrusiveness of the diagnostic 253 // command on the Java Virtual Machine behavior. The rational for this method is that some 254 // diagnostic commands can seriously disrupt the behavior of the Java Virtual Machine 255 // (for instance a Thread Dump for an application with several tens of thousands of threads, 256 // or a Head Dump with a 40GB+ heap size) and other diagnostic commands have no serious 257 // impact on the JVM (for instance, getting the command line arguments or the JVM version). 258 // The recommended format for the description is <impact level>: [longer description], 259 // where the impact level is selected among this list: {Low, Medium, High}. The optional 260 // longer description can provide more specific details like the fact that Thread Dump 261 // impact depends on the heap size. 262 static const char* impact() { return "Low: No impact"; } 263 264 // The permission() method returns the description of Java Permission. This 265 // permission is required when the diagnostic command is invoked via the 266 // DiagnosticCommandMBean. The rationale for this permission check is that 267 // the DiagnosticCommandMBean can be used to perform remote invocations of 268 // diagnostic commands through the PlatformMBeanServer. The (optional) Java 269 // Permission associated with each diagnostic command should ease the work 270 // of system administrators to write policy files granting permissions to 271 // execute diagnostic commands to remote users. Any diagnostic command with 272 // a potential impact on security should overwrite this method. 273 static const JavaPermission permission() { 274 JavaPermission p = {NULL, NULL, NULL}; 275 return p; 276 } 277 static int num_arguments() { return 0; } 278 outputStream* output() const { return _output; } 279 bool is_heap_allocated() const { return _is_heap_allocated; } 280 virtual void print_help(const char* name) const { 281 output()->print_cr("Syntax: %s", name); 282 } 283 virtual void parse(CmdLine* line, char delim, TRAPS) { 284 DCmdArgIter iter(line->args_addr(), line->args_len(), delim); 285 bool has_arg = iter.next(CHECK); 286 if (has_arg) { 287 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), 288 "The argument list of this diagnostic command should be empty."); 289 } 290 } 291 virtual void execute(DCmdSource source, TRAPS) { } 292 virtual void reset(TRAPS) { } 293 virtual void cleanup() { } 294 295 // support for the JMX interface 296 virtual GrowableArray<const char*>* argument_name_array() const { 297 GrowableArray<const char*>* array = new GrowableArray<const char*>(0); 298 return array; 299 } 300 virtual GrowableArray<DCmdArgumentInfo*>* argument_info_array() const { 301 GrowableArray<DCmdArgumentInfo*>* array = new GrowableArray<DCmdArgumentInfo*>(0); 302 return array; 303 } 304 305 // main method to invoke the framework 306 static void parse_and_execute(DCmdSource source, outputStream* out, const char* cmdline, 307 char delim, TRAPS); 308 }; 309 310 class DCmdWithParser : public DCmd { 311 protected: 312 DCmdParser _dcmdparser; 313 public: 314 DCmdWithParser (outputStream *output, bool heap=false) : DCmd(output, heap) { } 315 static const char* disabled_message() { return "Diagnostic command currently disabled"; } 316 static const char* impact() { return "Low: No impact"; } 317 virtual void parse(CmdLine *line, char delim, TRAPS); 318 virtual void execute(DCmdSource source, TRAPS) { } 319 virtual void reset(TRAPS); 320 virtual void cleanup(); 321 virtual void print_help(const char* name) const; 322 virtual GrowableArray<const char*>* argument_name_array() const; 323 virtual GrowableArray<DCmdArgumentInfo*>* argument_info_array() const; 324 }; 325 326 class DCmdMark : public StackObj { 327 DCmd* const _ref; 328 public: 329 DCmdMark(DCmd* cmd) : _ref(cmd) {} 330 ~DCmdMark() { 331 if (_ref != NULL) { 332 _ref->cleanup(); 333 if (_ref->is_heap_allocated()) { 334 delete _ref; 335 } 336 } 337 } 338 }; 339 340 // Diagnostic commands are not directly instantiated but created with a factory. 341 // Each diagnostic command class has its own factory. The DCmdFactory class also 342 // manages the status of the diagnostic command (hidden, enabled). A DCmdFactory 343 // has to be registered to make the diagnostic command available (see 344 // management.cpp) 345 class DCmdFactory: public CHeapObj<mtInternal> { 346 private: 347 static Mutex* _dcmdFactory_lock; 348 static bool _send_jmx_notification; 349 static bool _has_pending_jmx_notification; 350 static DCmdFactory* _DCmdFactoryList; 351 352 // Pointer to the next factory in the singly-linked list of registered 353 // diagnostic commands 354 DCmdFactory* _next; 355 // When disabled, a diagnostic command cannot be executed. Any attempt to 356 // execute it will result in the printing of the disabled message without 357 // instantiating the command. 358 const bool _enabled; 359 // When hidden, a diagnostic command doesn't appear in the list of commands 360 // provided by the 'help' command. 361 const bool _hidden; 362 const uint32_t _export_flags; 363 const int _num_arguments; 364 365 public: 366 DCmdFactory(int num_arguments, uint32_t flags, bool enabled, bool hidden) 367 : _next(NULL), _enabled(enabled), _hidden(hidden), 368 _export_flags(flags), _num_arguments(num_arguments) {} 369 bool is_enabled() const { return _enabled; } 370 bool is_hidden() const { return _hidden; } 371 uint32_t export_flags() const { return _export_flags; } 372 int num_arguments() const { return _num_arguments; } 373 DCmdFactory* next() const { return _next; } 374 virtual DCmd* create_resource_instance(outputStream* output) const = 0; 375 virtual const char* name() const = 0; 376 virtual const char* description() const = 0; 377 virtual const char* impact() const = 0; 378 virtual const JavaPermission permission() const = 0; 379 virtual const char* disabled_message() const = 0; 380 // Register a DCmdFactory to make a diagnostic command available. 381 // Once registered, a diagnostic command must not be unregistered. 382 // To prevent a diagnostic command from being executed, just set the 383 // enabled flag to false. 384 static int register_DCmdFactory(DCmdFactory* factory); 385 static DCmdFactory* factory(DCmdSource source, const char* cmd, size_t len); 386 // Returns a resourceArea allocated diagnostic command for the given command line 387 static DCmd* create_local_DCmd(DCmdSource source, CmdLine &line, outputStream* out, TRAPS); 388 static GrowableArray<const char*>* DCmd_list(DCmdSource source); 389 static GrowableArray<DCmdInfo*>* DCmdInfo_list(DCmdSource source); 390 391 static void set_jmx_notification_enabled(bool enabled) { 392 _send_jmx_notification = enabled; 393 } 394 static void push_jmx_notification_request(); 395 static bool has_pending_jmx_notification() { return _has_pending_jmx_notification; } 396 static void send_notification(TRAPS); 397 private: 398 static void send_notification_internal(TRAPS); 399 400 friend class HelpDCmd; 401 }; 402 403 // Template to easily create DCmdFactory instances. See management.cpp 404 // where this template is used to create and register factories. 405 template <class DCmdClass> class DCmdFactoryImpl : public DCmdFactory { 406 public: 407 DCmdFactoryImpl(uint32_t flags, bool enabled, bool hidden) : 408 DCmdFactory(DCmdClass::num_arguments(), flags, enabled, hidden) { } 409 // Returns a resourceArea allocated instance 410 DCmd* create_resource_instance(outputStream* output) const { 411 return new DCmdClass(output, false); 412 } 413 const char* name() const { 414 return DCmdClass::name(); 415 } 416 const char* description() const { 417 return DCmdClass::description(); 418 } 419 const char* impact() const { 420 return DCmdClass::impact(); 421 } 422 const JavaPermission permission() const { 423 return DCmdClass::permission(); 424 } 425 const char* disabled_message() const { 426 return DCmdClass::disabled_message(); 427 } 428 }; 429 430 // This class provides a convenient way to register Dcmds, without a need to change 431 // management.cpp every time. Body of these two methods resides in 432 // diagnosticCommand.cpp 433 434 class DCmdRegistrant : public AllStatic { 435 436 private: 437 static void register_dcmds(); 438 static void register_dcmds_ext(); 439 440 friend class Management; 441 }; 442 443 #endif // SHARE_VM_SERVICES_DIAGNOSTICFRAMEWORK_HPP