1 /*
2 * Copyright (C) 2015 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 #include <pthread.h>
18 #include <stdint.h>
19 #include <string.h>
20 #include <sys/types.h>
21 #include <time.h>
22 #include <ucontext.h>
23
24 #include "BacktraceLog.h"
25 #include "ThreadEntry.h"
26
27 // Initialize static member variables.
28 ThreadEntry* ThreadEntry::list_ = nullptr;
29 pthread_mutex_t ThreadEntry::list_mutex_ = PTHREAD_MUTEX_INITIALIZER;
30
31 // Assumes that ThreadEntry::list_mutex_ has already been locked before
32 // creating a ThreadEntry object.
ThreadEntry(pid_t pid,pid_t tid)33 ThreadEntry::ThreadEntry(pid_t pid, pid_t tid)
34 : pid_(pid), tid_(tid), ref_count_(1), mutex_(PTHREAD_MUTEX_INITIALIZER),
35 wait_mutex_(PTHREAD_MUTEX_INITIALIZER), wait_value_(0),
36 next_(ThreadEntry::list_), prev_(nullptr) {
37 pthread_condattr_t attr;
38 pthread_condattr_init(&attr);
39 pthread_condattr_setclock(&attr, CLOCK_MONOTONIC);
40 pthread_cond_init(&wait_cond_, &attr);
41
42 // Add ourselves to the list.
43 if (ThreadEntry::list_) {
44 ThreadEntry::list_->prev_ = this;
45 }
46 ThreadEntry::list_ = this;
47 }
48
Get(pid_t pid,pid_t tid,bool create)49 ThreadEntry* ThreadEntry::Get(pid_t pid, pid_t tid, bool create) {
50 pthread_mutex_lock(&ThreadEntry::list_mutex_);
51 ThreadEntry* entry = list_;
52 while (entry != nullptr) {
53 if (entry->Match(pid, tid)) {
54 break;
55 }
56 entry = entry->next_;
57 }
58
59 if (!entry) {
60 if (create) {
61 entry = new ThreadEntry(pid, tid);
62 }
63 } else {
64 entry->ref_count_++;
65 }
66 pthread_mutex_unlock(&ThreadEntry::list_mutex_);
67
68 return entry;
69 }
70
Remove(ThreadEntry * entry)71 void ThreadEntry::Remove(ThreadEntry* entry) {
72 entry->Unlock();
73
74 pthread_mutex_lock(&ThreadEntry::list_mutex_);
75 if (--entry->ref_count_ == 0) {
76 delete entry;
77 }
78 pthread_mutex_unlock(&ThreadEntry::list_mutex_);
79 }
80
81 // Assumes that ThreadEntry::list_mutex_ has already been locked before
82 // deleting a ThreadEntry object.
~ThreadEntry()83 ThreadEntry::~ThreadEntry() {
84 if (list_ == this) {
85 list_ = next_;
86 } else {
87 if (next_) {
88 next_->prev_ = prev_;
89 }
90 prev_->next_ = next_;
91 }
92
93 next_ = nullptr;
94 prev_ = nullptr;
95
96 pthread_cond_destroy(&wait_cond_);
97 }
98
Wait(int value)99 bool ThreadEntry::Wait(int value) {
100 timespec ts;
101 clock_gettime(CLOCK_MONOTONIC, &ts);
102 ts.tv_sec += 5;
103
104 bool wait_completed = true;
105 pthread_mutex_lock(&wait_mutex_);
106 while (wait_value_ != value) {
107 int ret = pthread_cond_timedwait(&wait_cond_, &wait_mutex_, &ts);
108 if (ret != 0) {
109 BACK_LOGW("pthread_cond_timedwait for value %d failed: %s", value, strerror(ret));
110 wait_completed = false;
111 break;
112 }
113 }
114 pthread_mutex_unlock(&wait_mutex_);
115
116 return wait_completed;
117 }
118
Wake()119 void ThreadEntry::Wake() {
120 pthread_mutex_lock(&wait_mutex_);
121 wait_value_++;
122 pthread_mutex_unlock(&wait_mutex_);
123
124 pthread_cond_signal(&wait_cond_);
125 }
126
CopyUcontextFromSigcontext(void * sigcontext)127 void ThreadEntry::CopyUcontextFromSigcontext(void* sigcontext) {
128 ucontext_t* ucontext = reinterpret_cast<ucontext_t*>(sigcontext);
129 // The only thing the unwinder cares about is the mcontext data.
130 memcpy(&ucontext_.uc_mcontext, &ucontext->uc_mcontext, sizeof(ucontext->uc_mcontext));
131 }
132