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() { return _cmd_len == 0; }
69 bool is_executable() { return is_empty() || _cmd[0] != '#'; }
70 bool is_stop() { 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* _str;
79 char _delim;
80 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 }
90 bool has_next() { return _cursor < _len; }
91 CmdLine next() {
92 assert(_cursor <= _len, "Cannot iterate more");
93 size_t n = _cursor;
94 while (n < _len && _str[n] != _delim) n++;
95 CmdLine line(&(_str[_cursor]), n - _cursor, false);
96 _cursor = n + 1;
97 // The default copy constructor of CmdLine is used to return a CmdLine
98 // instance to the caller.
99 return line;
100 }
101 };
102
103 // Iterator class to iterate over diagnostic command arguments
104 class DCmdArgIter : public ResourceObj {
105 const char* _buffer;
106 size_t _len;
107 size_t _cursor;
108 const char* _key_addr;
109 size_t _key_len;
110 const char* _value_addr;
111 size_t _value_len;
112 char _delim;
113 public:
114 DCmdArgIter(const char* buf, size_t len, char delim) {
115 _buffer = buf;
116 _len = len;
117 _delim = delim;
118 _cursor = 0;
119 }
120 bool next(TRAPS);
121 const char* key_addr() { return _key_addr; }
122 size_t key_length() { return _key_len; }
123 const char* value_addr() { return _value_addr; }
124 size_t value_length() { return _value_len; }
125 };
126
127 // A DCmdInfo instance provides a description of a diagnostic command. It is
128 // used to export the description to the JMX interface of the framework.
129 class DCmdInfo : public ResourceObj {
130 protected:
131 const char* _name; /* Name of the diagnostic command */
132 const char* _description; /* Short description */
133 const char* _impact; /* Impact on the JVM */
134 JavaPermission _permission; /* Java Permission required to execute this command if any */
135 int _num_arguments; /* Number of supported options or arguments */
136 bool _is_enabled; /* True if the diagnostic command can be invoked, false otherwise */
137 public:
138 DCmdInfo(const char* name,
139 const char* description,
140 const char* impact,
141 JavaPermission permission,
142 int num_arguments,
143 bool enabled) {
144 this->_name = name;
145 this->_description = description;
146 this->_impact = impact;
147 this->_permission = permission;
148 this->_num_arguments = num_arguments;
149 this->_is_enabled = enabled;
150 }
151 const char* name() const { return _name; }
152 const char* description() const { return _description; }
153 const char* impact() const { return _impact; }
154 JavaPermission permission() const { return _permission; }
155 int num_arguments() const { return _num_arguments; }
156 bool is_enabled() const { return _is_enabled; }
157
158 static bool by_name(void* name, DCmdInfo* info);
159 };
160
161 // A DCmdArgumentInfo instance provides a description of a diagnostic command
162 // argument. It is used to export the description to the JMX interface of the
163 // framework.
164 class DCmdArgumentInfo : public ResourceObj {
165 protected:
166 const char* _name; /* Option/Argument name*/
167 const char* _description; /* Short description */
168 const char* _type; /* Type: STRING, BOOLEAN, etc. */
169 const char* _default_string; /* Default value in a parsable string */
170 bool _mandatory; /* True if the option/argument is mandatory */
171 bool _option; /* True if it is an option, false if it is an argument */
172 /* (see diagnosticFramework.hpp for option/argument definitions) */
173 bool _multiple; /* True is the option can be specified several time */
174 int _position; /* Expected position for this argument (this field is */
175 /* meaningless for options) */
176 public:
177 DCmdArgumentInfo(const char* name, const char* description, const char* type,
178 const char* default_string, bool mandatory, bool option,
179 bool multiple) {
180 this->_name = name;
181 this->_description = description;
182 this->_type = type;
183 this->_default_string = default_string;
184 this->_option = option;
185 this->_mandatory = mandatory;
186 this->_option = option;
187 this->_multiple = multiple;
188 this->_position = -1;
189 }
190 DCmdArgumentInfo(const char* name, const char* description, const char* type,
191 const char* default_string, bool mandatory, bool option,
192 bool multiple, int position) {
193 this->_name = name;
194 this->_description = description;
195 this->_type = type;
196 this->_default_string = default_string;
197 this->_option = option;
198 this->_mandatory = mandatory;
199 this->_option = option;
200 this->_multiple = multiple;
201 this->_position = position;
202 }
203 const char* name() const { return _name; }
204 const char* description() const { return _description; }
205 const char* type() const { return _type; }
206 const char* default_string() const { return _default_string; }
207 bool is_mandatory() const { return _mandatory; }
208 bool is_option() const { return _option; }
209 bool is_multiple() const { return _multiple; }
210 int position() const { return _position; }
211 };
212
213 // The DCmdParser class can be used to create an argument parser for a
214 // diagnostic command. It is not mandatory to use it to parse arguments.
215 // The DCmdParser parses a CmdLine instance according to the parameters that
216 // have been declared by its associated diagnostic command. A parameter can
217 // either be an option or an argument. Options are identified by the option name
218 // while arguments are identified by their position in the command line. The
219 // position of an argument is defined relative to all arguments passed on the
220 // command line, options are not considered when defining an argument position.
221 // The generic syntax of a diagnostic command is:
222 //
223 // <command name> [<option>=<value>] [<argument_value>]
224 //
225 // Example:
226 //
227 // command_name option1=value1 option2=value argumentA argumentB argumentC
228 //
229 // In this command line, the diagnostic command receives five parameters, two
230 // options named option1 and option2, and three arguments. argumentA's position
231 // is 0, argumentB's position is 1 and argumentC's position is 2.
232 class DCmdParser {
233 private:
234 GenDCmdArgument* _options;
235 GenDCmdArgument* _arguments_list;
236 char _delim;
237 public:
238 DCmdParser() {
239 _options = NULL;
240 _arguments_list = NULL;
241 _delim = ' ';
242 }
243 void add_dcmd_option(GenDCmdArgument* arg);
244 void add_dcmd_argument(GenDCmdArgument* arg);
245 GenDCmdArgument* lookup_dcmd_option(const char* name, size_t len);
246 GenDCmdArgument* arguments_list() { return _arguments_list; };
247 void check(TRAPS);
248 void parse(CmdLine* line, char delim, TRAPS);
249 void print_help(outputStream* out, const char* cmd_name);
250 void reset(TRAPS);
251 void cleanup();
252 int num_arguments();
253 GrowableArray<const char*>* argument_name_array();
254 GrowableArray<DCmdArgumentInfo*>* argument_info_array();
255 };
256
257 // The DCmd class is the parent class of all diagnostic commands
258 // Diagnostic command instances should not be instantiated directly but
259 // created using the associated factory. The factory can be retrieved with
260 // the DCmdFactory::getFactory() method.
261 // A diagnostic command instance can either be allocated in the resource Area
262 // or in the C-heap. Allocation in the resource area is recommended when the
263 // current thread is the only one which will access the diagnostic command
264 // instance. Allocation in the C-heap is required when the diagnostic command
265 // is accessed by several threads (for instance to perform asynchronous
266 // execution).
267 // To ensure a proper cleanup, it's highly recommended to use a DCmdMark for
268 // each diagnostic command instance. In case of a C-heap allocated diagnostic
269 // command instance, the DCmdMark must be created in the context of the last
270 // thread that will access the instance.
271 class DCmd : public ResourceObj {
272 protected:
273 outputStream* _output;
274 bool _is_heap_allocated;
275 public:
276 DCmd(outputStream* output, bool heap_allocated) {
277 _output = output;
278 _is_heap_allocated = heap_allocated;
279 }
280
281 static const char* name() { return "No Name";}
282 static const char* description() { return "No Help";}
283 static const char* disabled_message() { return "Diagnostic command currently disabled"; }
284 // The impact() method returns a description of the intrusiveness of the diagnostic
285 // command on the Java Virtual Machine behavior. The rational for this method is that some
286 // diagnostic commands can seriously disrupt the behavior of the Java Virtual Machine
287 // (for instance a Thread Dump for an application with several tens of thousands of threads,
288 // or a Head Dump with a 40GB+ heap size) and other diagnostic commands have no serious
289 // impact on the JVM (for instance, getting the command line arguments or the JVM version).
290 // The recommended format for the description is <impact level>: [longer description],
291 // where the impact level is selected among this list: {Low, Medium, High}. The optional
292 // longer description can provide more specific details like the fact that Thread Dump
293 // impact depends on the heap size.
294 static const char* impact() { return "Low: No impact"; }
295 // The permission() method returns the description of Java Permission. This
296 // permission is required when the diagnostic command is invoked via the
297 // DiagnosticCommandMBean. The rationale for this permission check is that
298 // the DiagnosticCommandMBean can be used to perform remote invocations of
299 // diagnostic commands through the PlatformMBeanServer. The (optional) Java
300 // Permission associated with each diagnostic command should ease the work
301 // of system administrators to write policy files granting permissions to
302 // execute diagnostic commands to remote users. Any diagnostic command with
303 // a potential impact on security should overwrite this method.
304 static const JavaPermission permission() {
305 JavaPermission p = {NULL, NULL, NULL};
306 return p;
307 }
308 static int num_arguments() { return 0; }
309 outputStream* output() { return _output; }
310 bool is_heap_allocated() { return _is_heap_allocated; }
311 virtual void print_help(const char* name) {
312 output()->print_cr("Syntax: %s", name);
313 }
314 virtual void parse(CmdLine* line, char delim, TRAPS) {
315 DCmdArgIter iter(line->args_addr(), line->args_len(), delim);
316 bool has_arg = iter.next(CHECK);
317 if (has_arg) {
318 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
319 "The argument list of this diagnostic command should be empty.");
320 }
321 }
322 virtual void execute(DCmdSource source, TRAPS) { }
323 virtual void reset(TRAPS) { }
324 virtual void cleanup() { }
325
326 // support for the JMX interface
327 virtual GrowableArray<const char*>* argument_name_array() {
328 GrowableArray<const char*>* array = new GrowableArray<const char*>(0);
329 return array;
330 }
331 virtual GrowableArray<DCmdArgumentInfo*>* argument_info_array() {
332 GrowableArray<DCmdArgumentInfo*>* array = new GrowableArray<DCmdArgumentInfo*>(0);
333 return array;
334 }
335
336 // main method to invoke the framework
337 static void parse_and_execute(DCmdSource source, outputStream* out, const char* cmdline,
338 char delim, TRAPS);
339 };
340
341 class DCmdWithParser : public DCmd {
342 protected:
343 DCmdParser _dcmdparser;
344 public:
345 DCmdWithParser (outputStream *output, bool heap=false) : DCmd(output, heap) { }
346 static const char* name() { return "No Name";}
347 static const char* description() { return "No Help";}
348 static const char* disabled_message() { return "Diagnostic command currently disabled"; }
349 static const char* impact() { return "Low: No impact"; }
350 static const JavaPermission permission() {JavaPermission p = {NULL, NULL, NULL}; return p; }
351 static int num_arguments() { return 0; }
352 virtual void parse(CmdLine *line, char delim, TRAPS);
353 virtual void execute(DCmdSource source, TRAPS) { }
354 virtual void reset(TRAPS);
355 virtual void cleanup();
356 virtual void print_help(const char* name);
357 virtual GrowableArray<const char*>* argument_name_array();
358 virtual GrowableArray<DCmdArgumentInfo*>* argument_info_array();
359 };
360
361 class DCmdMark : public StackObj {
362 DCmd* _ref;
363 public:
364 DCmdMark(DCmd* cmd) { _ref = cmd; }
365 ~DCmdMark() {
366 if (_ref != NULL) {
367 _ref->cleanup();
368 if (_ref->is_heap_allocated()) {
369 delete _ref;
370 }
371 }
372 }
373 };
374
375 // Diagnostic commands are not directly instantiated but created with a factory.
376 // Each diagnostic command class has its own factory. The DCmdFactory class also
377 // manages the status of the diagnostic command (hidden, enabled). A DCmdFactory
378 // has to be registered to make the diagnostic command available (see
379 // management.cpp)
380 class DCmdFactory: public CHeapObj<mtInternal> {
381 private:
382 static Mutex* _dcmdFactory_lock;
383 static bool _send_jmx_notification;
384 static bool _has_pending_jmx_notification;
385 // Pointer to the next factory in the singly-linked list of registered
386 // diagnostic commands
387 DCmdFactory* _next;
388 // When disabled, a diagnostic command cannot be executed. Any attempt to
389 // execute it will result in the printing of the disabled message without
390 // instantiating the command.
391 bool _enabled;
392 // When hidden, a diagnostic command doesn't appear in the list of commands
393 // provided by the 'help' command.
394 bool _hidden;
395 uint32_t _export_flags;
396 int _num_arguments;
397 static DCmdFactory* _DCmdFactoryList;
398 public:
399 DCmdFactory(int num_arguments, uint32_t flags, bool enabled, bool hidden) {
400 _next = NULL;
401 _enabled = enabled;
402 _hidden = hidden;
403 _export_flags = flags;
404 _num_arguments = num_arguments;
405 }
406 bool is_enabled() const { return _enabled; }
407 void set_enabled(bool b) { _enabled = b; }
408 bool is_hidden() const { return _hidden; }
409 void set_hidden(bool b) { _hidden = b; }
410 uint32_t export_flags() { return _export_flags; }
411 void set_export_flags(uint32_t f) { _export_flags = f; }
412 int num_arguments() { return _num_arguments; }
413 DCmdFactory* next() { return _next; }
414 virtual DCmd* create_Cheap_instance(outputStream* output) = 0;
415 virtual DCmd* create_resource_instance(outputStream* output) = 0;
416 virtual const char* name() const = 0;
417 virtual const char* description() const = 0;
418 virtual const char* impact() const = 0;
419 virtual const JavaPermission permission() const = 0;
420 virtual const char* disabled_message() const = 0;
421 // Register a DCmdFactory to make a diagnostic command available.
422 // Once registered, a diagnostic command must not be unregistered.
423 // To prevent a diagnostic command from being executed, just set the
424 // enabled flag to false.
425 static int register_DCmdFactory(DCmdFactory* factory);
426 static DCmdFactory* factory(DCmdSource source, const char* cmd, size_t len);
427 // Returns a C-heap allocated diagnostic command for the given command line
428 static DCmd* create_global_DCmd(DCmdSource source, CmdLine &line, outputStream* out, TRAPS);
429 // Returns a resourceArea allocated diagnostic command for the given command line
430 static DCmd* create_local_DCmd(DCmdSource source, CmdLine &line, outputStream* out, TRAPS);
431 static GrowableArray<const char*>* DCmd_list(DCmdSource source);
432 static GrowableArray<DCmdInfo*>* DCmdInfo_list(DCmdSource source);
433
434 static void set_jmx_notification_enabled(bool enabled) {
435 _send_jmx_notification = enabled;
436 }
437 static void push_jmx_notification_request();
438 static bool has_pending_jmx_notification() { return _has_pending_jmx_notification; }
439 static void send_notification(TRAPS);
440 private:
441 static void send_notification_internal(TRAPS);
442
443 friend class HelpDCmd;
444 };
445
446 // Template to easily create DCmdFactory instances. See management.cpp
447 // where this template is used to create and register factories.
448 template <class DCmdClass> class DCmdFactoryImpl : public DCmdFactory {
449 public:
450 DCmdFactoryImpl(uint32_t flags, bool enabled, bool hidden) :
451 DCmdFactory(DCmdClass::num_arguments(), flags, enabled, hidden) { }
452 // Returns a C-heap allocated instance
453 virtual DCmd* create_Cheap_instance(outputStream* output) {
454 return new (ResourceObj::C_HEAP, mtInternal) DCmdClass(output, true);
455 }
456 // Returns a resourceArea allocated instance
457 virtual DCmd* create_resource_instance(outputStream* output) {
458 return new DCmdClass(output, false);
459 }
460 virtual const char* name() const {
461 return DCmdClass::name();
462 }
463 virtual const char* description() const {
464 return DCmdClass::description();
465 }
466 virtual const char* impact() const {
467 return DCmdClass::impact();
468 }
469 virtual const JavaPermission permission() const {
470 return DCmdClass::permission();
471 }
472 virtual const char* disabled_message() const {
473 return DCmdClass::disabled_message();
474 }
475 };
476
477 // This class provides a convenient way to register Dcmds, without a need to change
478 // management.cpp every time. Body of these two methods resides in
479 // diagnosticCommand.cpp
480
481 class DCmdRegistrant : public AllStatic {
482
483 private:
484 static void register_dcmds();
485 static void register_dcmds_ext();
486
487 friend class Management;
488 };
489
490 #endif // SHARE_VM_SERVICES_DIAGNOSTICFRAMEWORK_HPP