1 /*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #ifndef ART_RUNTIME_JDWP_JDWP_H_
18 #define ART_RUNTIME_JDWP_JDWP_H_
19
20 #include "atomic.h"
21 #include "base/mutex.h"
22 #include "jdwp/jdwp_bits.h"
23 #include "jdwp/jdwp_constants.h"
24 #include "jdwp/jdwp_expand_buf.h"
25
26 #include <pthread.h>
27 #include <stddef.h>
28 #include <stdint.h>
29 #include <string.h>
30 #include <vector>
31
32 struct iovec;
33
34 namespace art {
35
36 class ArtField;
37 class ArtMethod;
38 union JValue;
39 class Thread;
40
41 namespace mirror {
42 class Class;
43 class Object;
44 class Throwable;
45 } // namespace mirror
46 class Thread;
47
48 namespace JDWP {
49
50 /*
51 * Fundamental types.
52 *
53 * ObjectId and RefTypeId must be the same size.
54 * Its OK to change MethodId and FieldId sizes as long as the size is <= 8 bytes.
55 * Note that ArtFields are 64 bit pointers on 64 bit targets. So this one must remain 8 bytes.
56 */
57 typedef uint64_t FieldId; /* static or instance field */
58 typedef uint64_t MethodId; /* any kind of method, including constructors */
59 typedef uint64_t ObjectId; /* any object (threadID, stringID, arrayID, etc) */
60 typedef uint64_t RefTypeId; /* like ObjectID, but unique for Class objects */
61 typedef uint64_t FrameId; /* short-lived stack frame ID */
62
63 ObjectId ReadObjectId(const uint8_t** pBuf);
64
SetFieldId(uint8_t * buf,FieldId val)65 static inline void SetFieldId(uint8_t* buf, FieldId val) { return Set8BE(buf, val); }
SetMethodId(uint8_t * buf,MethodId val)66 static inline void SetMethodId(uint8_t* buf, MethodId val) { return Set8BE(buf, val); }
SetObjectId(uint8_t * buf,ObjectId val)67 static inline void SetObjectId(uint8_t* buf, ObjectId val) { return Set8BE(buf, val); }
SetRefTypeId(uint8_t * buf,RefTypeId val)68 static inline void SetRefTypeId(uint8_t* buf, RefTypeId val) { return Set8BE(buf, val); }
SetFrameId(uint8_t * buf,FrameId val)69 static inline void SetFrameId(uint8_t* buf, FrameId val) { return Set8BE(buf, val); }
expandBufAddFieldId(ExpandBuf * pReply,FieldId id)70 static inline void expandBufAddFieldId(ExpandBuf* pReply, FieldId id) { expandBufAdd8BE(pReply, id); }
expandBufAddMethodId(ExpandBuf * pReply,MethodId id)71 static inline void expandBufAddMethodId(ExpandBuf* pReply, MethodId id) { expandBufAdd8BE(pReply, id); }
expandBufAddObjectId(ExpandBuf * pReply,ObjectId id)72 static inline void expandBufAddObjectId(ExpandBuf* pReply, ObjectId id) { expandBufAdd8BE(pReply, id); }
expandBufAddRefTypeId(ExpandBuf * pReply,RefTypeId id)73 static inline void expandBufAddRefTypeId(ExpandBuf* pReply, RefTypeId id) { expandBufAdd8BE(pReply, id); }
expandBufAddFrameId(ExpandBuf * pReply,FrameId id)74 static inline void expandBufAddFrameId(ExpandBuf* pReply, FrameId id) { expandBufAdd8BE(pReply, id); }
75
76 struct EventLocation {
77 ArtMethod* method;
78 uint32_t dex_pc;
79 };
80
81 /*
82 * Holds a JDWP "location".
83 */
84 struct JdwpLocation {
85 JdwpTypeTag type_tag;
86 RefTypeId class_id;
87 MethodId method_id;
88 uint64_t dex_pc;
89 };
90 std::ostream& operator<<(std::ostream& os, const JdwpLocation& rhs)
91 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
92 bool operator==(const JdwpLocation& lhs, const JdwpLocation& rhs);
93 bool operator!=(const JdwpLocation& lhs, const JdwpLocation& rhs);
94
95 /*
96 * How we talk to the debugger.
97 */
98 enum JdwpTransportType {
99 kJdwpTransportUnknown = 0,
100 kJdwpTransportSocket, // transport=dt_socket
101 kJdwpTransportAndroidAdb, // transport=dt_android_adb
102 };
103 std::ostream& operator<<(std::ostream& os, const JdwpTransportType& rhs);
104
105 struct JdwpOptions {
106 JdwpTransportType transport = kJdwpTransportUnknown;
107 bool server = false;
108 bool suspend = false;
109 std::string host = "";
110 uint16_t port = static_cast<uint16_t>(-1);
111 };
112
113 bool operator==(const JdwpOptions& lhs, const JdwpOptions& rhs);
114
115 struct JdwpEvent;
116 class JdwpNetStateBase;
117 struct ModBasket;
118 class Request;
119
120 /*
121 * State for JDWP functions.
122 */
123 struct JdwpState {
124 /*
125 * Perform one-time initialization.
126 *
127 * Among other things, this binds to a port to listen for a connection from
128 * the debugger.
129 *
130 * Returns a newly-allocated JdwpState struct on success, or nullptr on failure.
131 */
132 static JdwpState* Create(const JdwpOptions* options)
133 LOCKS_EXCLUDED(Locks::mutator_lock_);
134
135 ~JdwpState();
136
137 /*
138 * Returns "true" if a debugger or DDM is connected.
139 */
140 bool IsActive();
141
142 /**
143 * Returns the Thread* for the JDWP daemon thread.
144 */
145 Thread* GetDebugThread();
146
147 /*
148 * Get time, in milliseconds, since the last debugger activity.
149 */
150 int64_t LastDebuggerActivity();
151
152 void ExitAfterReplying(int exit_status);
153
154 // Acquires/releases the JDWP synchronization token for the debugger
155 // thread (command handler) so no event thread posts an event while
156 // it processes a command. This must be called only from the debugger
157 // thread.
158 void AcquireJdwpTokenForCommand() LOCKS_EXCLUDED(jdwp_token_lock_);
159 void ReleaseJdwpTokenForCommand() LOCKS_EXCLUDED(jdwp_token_lock_);
160
161 // Acquires/releases the JDWP synchronization token for the event thread
162 // so no other thread (debugger thread or event thread) interleaves with
163 // it when posting an event. This must NOT be called from the debugger
164 // thread, only event thread.
165 void AcquireJdwpTokenForEvent(ObjectId threadId) LOCKS_EXCLUDED(jdwp_token_lock_);
166 void ReleaseJdwpTokenForEvent() LOCKS_EXCLUDED(jdwp_token_lock_);
167
168 /*
169 * These notify the debug code that something interesting has happened. This
170 * could be a thread starting or ending, an exception, or an opportunity
171 * for a breakpoint. These calls do not mean that an event the debugger
172 * is interested has happened, just that something has happened that the
173 * debugger *might* be interested in.
174 *
175 * The item of interest may trigger multiple events, some or all of which
176 * are grouped together in a single response.
177 *
178 * The event may cause the current thread or all threads (except the
179 * JDWP support thread) to be suspended.
180 */
181
182 /*
183 * The VM has finished initializing. Only called when the debugger is
184 * connected at the time initialization completes.
185 */
186 void PostVMStart() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
187
188 /*
189 * A location of interest has been reached. This is used for breakpoints,
190 * single-stepping, and method entry/exit. (JDWP requires that these four
191 * events are grouped together in a single response.)
192 *
193 * In some cases "*pLoc" will just have a method and class name, e.g. when
194 * issuing a MethodEntry on a native method.
195 *
196 * "eventFlags" indicates the types of events that have occurred.
197 *
198 * "returnValue" is non-null for MethodExit events only.
199 */
200 void PostLocationEvent(const EventLocation* pLoc, mirror::Object* thisPtr, int eventFlags,
201 const JValue* returnValue)
202 LOCKS_EXCLUDED(event_list_lock_)
203 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
204
205 /*
206 * A field of interest has been accessed or modified. This is used for field access and field
207 * modification events.
208 *
209 * "fieldValue" is non-null for field modification events only.
210 * "is_modification" is true for field modification, false for field access.
211 */
212 void PostFieldEvent(const EventLocation* pLoc, ArtField* field, mirror::Object* thisPtr,
213 const JValue* fieldValue, bool is_modification)
214 LOCKS_EXCLUDED(event_list_lock_)
215 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
216
217 /*
218 * An exception has been thrown.
219 *
220 * Pass in a zeroed-out "*pCatchLoc" if the exception wasn't caught.
221 */
222 void PostException(const EventLocation* pThrowLoc, mirror::Throwable* exception_object,
223 const EventLocation* pCatchLoc, mirror::Object* thisPtr)
224 LOCKS_EXCLUDED(event_list_lock_)
225 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
226
227 /*
228 * A thread has started or stopped.
229 */
230 void PostThreadChange(Thread* thread, bool start)
231 LOCKS_EXCLUDED(event_list_lock_)
232 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
233
234 /*
235 * Class has been prepared.
236 */
237 void PostClassPrepare(mirror::Class* klass)
238 LOCKS_EXCLUDED(event_list_lock_)
239 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
240
241 /*
242 * The VM is about to stop.
243 */
244 bool PostVMDeath();
245
246 // Called if/when we realize we're talking to DDMS.
247 void NotifyDdmsActive() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
248
249
250 void SetupChunkHeader(uint32_t type, size_t data_len, size_t header_size, uint8_t* out_header);
251
252 /*
253 * Send up a chunk of DDM data.
254 */
255 void DdmSendChunkV(uint32_t type, const iovec* iov, int iov_count)
256 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
257
258 bool HandlePacket();
259
260 void SendRequest(ExpandBuf* pReq);
261
262 void ResetState()
263 LOCKS_EXCLUDED(event_list_lock_)
264 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
265
266 /* atomic ops to get next serial number */
267 uint32_t NextRequestSerial();
268 uint32_t NextEventSerial();
269
270 void Run()
271 LOCKS_EXCLUDED(Locks::mutator_lock_,
272 Locks::thread_suspend_count_lock_);
273
274 /*
275 * Register an event by adding it to the event list.
276 *
277 * "*pEvent" must be storage allocated with jdwpEventAlloc(). The caller
278 * may discard its pointer after calling this.
279 */
280 JdwpError RegisterEvent(JdwpEvent* pEvent)
281 LOCKS_EXCLUDED(event_list_lock_)
282 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
283
284 /*
285 * Unregister an event, given the requestId.
286 */
287 void UnregisterEventById(uint32_t requestId)
288 LOCKS_EXCLUDED(event_list_lock_)
289 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
290
291 /*
292 * Unregister all events.
293 */
294 void UnregisterAll()
295 LOCKS_EXCLUDED(event_list_lock_)
296 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
297
298 private:
299 explicit JdwpState(const JdwpOptions* options);
300 size_t ProcessRequest(Request* request, ExpandBuf* pReply, bool* skip_reply);
301 bool InvokeInProgress();
302 bool IsConnected();
303 void SuspendByPolicy(JdwpSuspendPolicy suspend_policy, JDWP::ObjectId thread_self_id)
304 LOCKS_EXCLUDED(Locks::mutator_lock_);
305 void SendRequestAndPossiblySuspend(ExpandBuf* pReq, JdwpSuspendPolicy suspend_policy,
306 ObjectId threadId)
307 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
308 void CleanupMatchList(const std::vector<JdwpEvent*>& match_list)
309 EXCLUSIVE_LOCKS_REQUIRED(event_list_lock_)
310 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
311 void EventFinish(ExpandBuf* pReq);
312 bool FindMatchingEvents(JdwpEventKind eventKind, const ModBasket& basket,
313 std::vector<JdwpEvent*>* match_list)
314 LOCKS_EXCLUDED(event_list_lock_)
315 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
316 void FindMatchingEventsLocked(JdwpEventKind eventKind, const ModBasket& basket,
317 std::vector<JdwpEvent*>* match_list)
318 EXCLUSIVE_LOCKS_REQUIRED(event_list_lock_)
319 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
320 void UnregisterEvent(JdwpEvent* pEvent)
321 EXCLUSIVE_LOCKS_REQUIRED(event_list_lock_)
322 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
323 void SendBufferedRequest(uint32_t type, const std::vector<iovec>& iov);
324
325 /*
326 * When we hit a debugger event that requires suspension, it's important
327 * that we wait for the thread to suspend itself before processing any
328 * additional requests. Otherwise, if the debugger immediately sends a
329 * "resume thread" command, the resume might arrive before the thread has
330 * suspended itself.
331 *
332 * It's also important no event thread suspends while we process a command
333 * from the debugger. Otherwise we could post an event ("thread death")
334 * before sending the reply of the command being processed ("resume") and
335 * cause bad synchronization with the debugger.
336 *
337 * The thread wanting "exclusive" access to the JDWP world must call the
338 * SetWaitForJdwpToken method before processing a command from the
339 * debugger or sending an event to the debugger.
340 * Once the command is processed or the event thread has posted its event,
341 * it must call the ClearWaitForJdwpToken method to allow another thread
342 * to do JDWP stuff.
343 *
344 * Therefore the main JDWP handler loop will wait for the event thread
345 * suspension before processing the next command. Once the event thread
346 * has suspended itself and cleared the token, the JDWP handler continues
347 * processing commands. This works in the suspend-all case because the
348 * event thread doesn't suspend itself until everything else has suspended.
349 *
350 * It's possible that multiple threads could encounter thread-suspending
351 * events at the same time, so we grab a mutex in the SetWaitForJdwpToken
352 * call, and release it in the ClearWaitForJdwpToken call.
353 */
354 void SetWaitForJdwpToken(ObjectId threadId) LOCKS_EXCLUDED(jdwp_token_lock_);
355 void ClearWaitForJdwpToken() LOCKS_EXCLUDED(jdwp_token_lock_);
356
357 public: // TODO: fix privacy
358 const JdwpOptions* options_;
359
360 private:
361 /* wait for creation of the JDWP thread */
362 Mutex thread_start_lock_ DEFAULT_MUTEX_ACQUIRED_AFTER;
363 ConditionVariable thread_start_cond_ GUARDED_BY(thread_start_lock_);
364
365 pthread_t pthread_;
366 Thread* thread_;
367
368 volatile int32_t debug_thread_started_ GUARDED_BY(thread_start_lock_);
369 ObjectId debug_thread_id_;
370
371 private:
372 bool run;
373
374 public: // TODO: fix privacy
375 JdwpNetStateBase* netState;
376
377 private:
378 // For wait-for-debugger.
379 Mutex attach_lock_ ACQUIRED_AFTER(thread_start_lock_);
380 ConditionVariable attach_cond_ GUARDED_BY(attach_lock_);
381
382 // Time of last debugger activity, in milliseconds.
383 Atomic<int64_t> last_activity_time_ms_;
384
385 // Global counters and a mutex to protect them.
386 AtomicInteger request_serial_;
387 AtomicInteger event_serial_;
388
389 // Linked list of events requested by the debugger (breakpoints, class prep, etc).
390 Mutex event_list_lock_ DEFAULT_MUTEX_ACQUIRED_AFTER ACQUIRED_BEFORE(Locks::breakpoint_lock_);
391 JdwpEvent* event_list_ GUARDED_BY(event_list_lock_);
392 size_t event_list_size_ GUARDED_BY(event_list_lock_); // Number of elements in event_list_.
393
394 // Used to synchronize JDWP command handler thread and event threads so only one
395 // thread does JDWP stuff at a time. This prevent from interleaving command handling
396 // and event notification. Otherwise we could receive a "resume" command for an
397 // event thread that is not suspended yet, or post a "thread death" or event "VM death"
398 // event before sending the reply of the "resume" command that caused it.
399 Mutex jdwp_token_lock_ DEFAULT_MUTEX_ACQUIRED_AFTER;
400 ConditionVariable jdwp_token_cond_ GUARDED_BY(jdwp_token_lock_);
401 ObjectId jdwp_token_owner_thread_id_;
402
403 bool ddm_is_active_;
404
405 // Used for VirtualMachine.Exit command handling.
406 bool should_exit_;
407 int exit_status_;
408
409 // Used to synchronize runtime shutdown with JDWP command handler thread.
410 // When the runtime shuts down, it needs to stop JDWP command handler thread by closing the
411 // JDWP connection. However, if the JDWP thread is processing a command, it needs to wait
412 // for the command to finish so we can send its reply before closing the connection.
413 Mutex shutdown_lock_ ACQUIRED_AFTER(event_list_lock_);
414 ConditionVariable shutdown_cond_ GUARDED_BY(shutdown_lock_);
415 bool processing_request_ GUARDED_BY(shutdown_lock_);
416 };
417
418 std::string DescribeField(const FieldId& field_id) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
419 std::string DescribeMethod(const MethodId& method_id) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
420 std::string DescribeRefTypeId(const RefTypeId& ref_type_id) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
421
422 class Request {
423 public:
424 Request(const uint8_t* bytes, uint32_t available);
425 ~Request();
426
427 std::string ReadUtf8String();
428
429 // Helper function: read a variable-width value from the input buffer.
430 uint64_t ReadValue(size_t width);
431
432 int32_t ReadSigned32(const char* what);
433
434 uint32_t ReadUnsigned32(const char* what);
435
436 FieldId ReadFieldId() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
437
438 MethodId ReadMethodId() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
439
440 ObjectId ReadObjectId(const char* specific_kind);
441
442 ObjectId ReadArrayId();
443
444 ObjectId ReadObjectId();
445
446 ObjectId ReadThreadId();
447
448 ObjectId ReadThreadGroupId();
449
450 RefTypeId ReadRefTypeId() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
451
452 FrameId ReadFrameId();
453
ReadEnum1(const char * specific_kind)454 template <typename T> T ReadEnum1(const char* specific_kind) {
455 T value = static_cast<T>(Read1());
456 VLOG(jdwp) << " " << specific_kind << " " << value;
457 return value;
458 }
459
460 JdwpTag ReadTag();
461
462 JdwpTypeTag ReadTypeTag();
463
464 JdwpLocation ReadLocation() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
465
466 JdwpModKind ReadModKind();
467
468 //
469 // Return values from this JDWP packet's header.
470 //
GetLength()471 size_t GetLength() { return byte_count_; }
GetId()472 uint32_t GetId() { return id_; }
GetCommandSet()473 uint8_t GetCommandSet() { return command_set_; }
GetCommand()474 uint8_t GetCommand() { return command_; }
475
476 // Returns the number of bytes remaining.
size()477 size_t size() { return end_ - p_; }
478
479 // Returns a pointer to the next byte.
data()480 const uint8_t* data() { return p_; }
481
Skip(size_t count)482 void Skip(size_t count) { p_ += count; }
483
484 void CheckConsumed();
485
486 private:
487 uint8_t Read1();
488 uint16_t Read2BE();
489 uint32_t Read4BE();
490 uint64_t Read8BE();
491
492 uint32_t byte_count_;
493 uint32_t id_;
494 uint8_t command_set_;
495 uint8_t command_;
496
497 const uint8_t* p_;
498 const uint8_t* end_;
499
500 DISALLOW_COPY_AND_ASSIGN(Request);
501 };
502
503 } // namespace JDWP
504
505 } // namespace art
506
507 #endif // ART_RUNTIME_JDWP_JDWP_H_
508