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