1/*
2 * Copyright (c) 2011, 2019, 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_SERVICES_DIAGNOSTICFRAMEWORK_HPP
26#define SHARE_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
36enum 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.
46struct 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
56class CmdLine : public StackObj {
57private:
58 const char* _cmd;
59 size_t _cmd_len;
60 const char* _args;
61 size_t _args_len;
62public:
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.
75class DCmdIter : public StackObj {
76 friend class DCmd;
77private:
78 const char* const _str;
79 const char _delim;
80 const size_t _len;
81 size_t _cursor;
82public:
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
101class 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;
110public:
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.
124class DCmdInfo : public ResourceObj {
125protected:
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 */
132public:
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.
154class DCmdArgumentInfo : public ResourceObj {
155protected:
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) */
166public:
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.
203class DCmdParser {
204private:
205 GenDCmdArgument* _options;
206 GenDCmdArgument* _arguments_list;
207public:
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.
238class DCmd : public ResourceObj {
239protected:
240 outputStream* const _output;
241 const bool _is_heap_allocated;
242public:
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
310class DCmdWithParser : public DCmd {
311protected:
312 DCmdParser _dcmdparser;
313public:
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
326class DCmdMark : public StackObj {
327 DCmd* const _ref;
328public:
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)
345class DCmdFactory: public CHeapObj<mtInternal> {
346private:
347 static bool _send_jmx_notification;
348 static bool _has_pending_jmx_notification;
349 static DCmdFactory* _DCmdFactoryList;
350
351 // Pointer to the next factory in the singly-linked list of registered
352 // diagnostic commands
353 DCmdFactory* _next;
354 // When disabled, a diagnostic command cannot be executed. Any attempt to
355 // execute it will result in the printing of the disabled message without
356 // instantiating the command.
357 const bool _enabled;
358 // When hidden, a diagnostic command doesn't appear in the list of commands
359 // provided by the 'help' command.
360 const bool _hidden;
361 const uint32_t _export_flags;
362 const int _num_arguments;
363
364public:
365 DCmdFactory(int num_arguments, uint32_t flags, bool enabled, bool hidden)
366 : _next(NULL), _enabled(enabled), _hidden(hidden),
367 _export_flags(flags), _num_arguments(num_arguments) {}
368 bool is_enabled() const { return _enabled; }
369 bool is_hidden() const { return _hidden; }
370 uint32_t export_flags() const { return _export_flags; }
371 int num_arguments() const { return _num_arguments; }
372 DCmdFactory* next() const { return _next; }
373 virtual DCmd* create_resource_instance(outputStream* output) const = 0;
374 virtual const char* name() const = 0;
375 virtual const char* description() const = 0;
376 virtual const char* impact() const = 0;
377 virtual const JavaPermission permission() const = 0;
378 virtual const char* disabled_message() const = 0;
379 // Register a DCmdFactory to make a diagnostic command available.
380 // Once registered, a diagnostic command must not be unregistered.
381 // To prevent a diagnostic command from being executed, just set the
382 // enabled flag to false.
383 static int register_DCmdFactory(DCmdFactory* factory);
384 static DCmdFactory* factory(DCmdSource source, const char* cmd, size_t len);
385 // Returns a resourceArea allocated diagnostic command for the given command line
386 static DCmd* create_local_DCmd(DCmdSource source, CmdLine &line, outputStream* out, TRAPS);
387 static GrowableArray<const char*>* DCmd_list(DCmdSource source);
388 static GrowableArray<DCmdInfo*>* DCmdInfo_list(DCmdSource source);
389
390 static void set_jmx_notification_enabled(bool enabled) {
391 _send_jmx_notification = enabled;
392 }
393 static void push_jmx_notification_request();
394 static bool has_pending_jmx_notification() { return _has_pending_jmx_notification; }
395 static void send_notification(TRAPS);
396private:
397 static void send_notification_internal(TRAPS);
398
399 friend class HelpDCmd;
400};
401
402// Template to easily create DCmdFactory instances. See management.cpp
403// where this template is used to create and register factories.
404template <class DCmdClass> class DCmdFactoryImpl : public DCmdFactory {
405public:
406 DCmdFactoryImpl(uint32_t flags, bool enabled, bool hidden) :
407 DCmdFactory(DCmdClass::num_arguments(), flags, enabled, hidden) { }
408 // Returns a resourceArea allocated instance
409 DCmd* create_resource_instance(outputStream* output) const {
410 return new DCmdClass(output, false);
411 }
412 const char* name() const {
413 return DCmdClass::name();
414 }
415 const char* description() const {
416 return DCmdClass::description();
417 }
418 const char* impact() const {
419 return DCmdClass::impact();
420 }
421 const JavaPermission permission() const {
422 return DCmdClass::permission();
423 }
424 const char* disabled_message() const {
425 return DCmdClass::disabled_message();
426 }
427};
428
429// This class provides a convenient way to register Dcmds, without a need to change
430// management.cpp every time. Body of these two methods resides in
431// diagnosticCommand.cpp
432
433class DCmdRegistrant : public AllStatic {
434
435private:
436 static void register_dcmds();
437 static void register_dcmds_ext();
438
439 friend class Management;
440};
441
442#endif // SHARE_SERVICES_DIAGNOSTICFRAMEWORK_HPP
443