1 /******************************************************************************
2 *
3 * Copyright (C) 2014 Google, Inc.
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at:
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 ******************************************************************************/
18
19 #define LOG_TAG "bt_osi_thread"
20
21 #include "osi/include/thread.h"
22
23 #include <assert.h>
24 #include <errno.h>
25 #include <malloc.h>
26 #include <pthread.h>
27 #include <string.h>
28 #include <sys/prctl.h>
29 #include <sys/resource.h>
30 #include <sys/types.h>
31
32 #include "osi/include/allocator.h"
33 #include "osi/include/compat.h"
34 #include "osi/include/fixed_queue.h"
35 #include "osi/include/log.h"
36 #include "osi/include/reactor.h"
37 #include "osi/include/semaphore.h"
38
39 struct thread_t {
40 bool is_joined;
41 pthread_t pthread;
42 pid_t tid;
43 char name[THREAD_NAME_MAX + 1];
44 reactor_t *reactor;
45 fixed_queue_t *work_queue;
46 };
47
48 struct start_arg {
49 thread_t *thread;
50 semaphore_t *start_sem;
51 int error;
52 };
53
54 typedef struct {
55 thread_fn func;
56 void *context;
57 } work_item_t;
58
59 static void *run_thread(void *start_arg);
60 static void work_queue_read_cb(void *context);
61
62 static const size_t DEFAULT_WORK_QUEUE_CAPACITY = 128;
63
thread_new_sized(const char * name,size_t work_queue_capacity)64 thread_t *thread_new_sized(const char *name, size_t work_queue_capacity) {
65 assert(name != NULL);
66 assert(work_queue_capacity != 0);
67
68 thread_t *ret = osi_calloc(sizeof(thread_t));
69
70 ret->reactor = reactor_new();
71 if (!ret->reactor)
72 goto error;
73
74 ret->work_queue = fixed_queue_new(work_queue_capacity);
75 if (!ret->work_queue)
76 goto error;
77
78 // Start is on the stack, but we use a semaphore, so it's safe
79 struct start_arg start;
80 start.start_sem = semaphore_new(0);
81 if (!start.start_sem)
82 goto error;
83
84 strncpy(ret->name, name, THREAD_NAME_MAX);
85 start.thread = ret;
86 start.error = 0;
87 pthread_create(&ret->pthread, NULL, run_thread, &start);
88 semaphore_wait(start.start_sem);
89 semaphore_free(start.start_sem);
90
91 if (start.error)
92 goto error;
93
94 return ret;
95
96 error:;
97 if (ret) {
98 fixed_queue_free(ret->work_queue, osi_free);
99 reactor_free(ret->reactor);
100 }
101 osi_free(ret);
102 return NULL;
103 }
104
thread_new(const char * name)105 thread_t *thread_new(const char *name) {
106 return thread_new_sized(name, DEFAULT_WORK_QUEUE_CAPACITY);
107 }
108
thread_free(thread_t * thread)109 void thread_free(thread_t *thread) {
110 if (!thread)
111 return;
112
113 thread_stop(thread);
114 thread_join(thread);
115
116 fixed_queue_free(thread->work_queue, osi_free);
117 reactor_free(thread->reactor);
118 osi_free(thread);
119 }
120
thread_join(thread_t * thread)121 void thread_join(thread_t *thread) {
122 assert(thread != NULL);
123
124 // TODO(zachoverflow): use a compare and swap when ready
125 if (!thread->is_joined) {
126 thread->is_joined = true;
127 pthread_join(thread->pthread, NULL);
128 }
129 }
130
thread_post(thread_t * thread,thread_fn func,void * context)131 bool thread_post(thread_t *thread, thread_fn func, void *context) {
132 assert(thread != NULL);
133 assert(func != NULL);
134
135 // TODO(sharvil): if the current thread == |thread| and we've run out
136 // of queue space, we should abort this operation, otherwise we'll
137 // deadlock.
138
139 // Queue item is freed either when the queue itself is destroyed
140 // or when the item is removed from the queue for dispatch.
141 work_item_t *item = (work_item_t *)osi_malloc(sizeof(work_item_t));
142 item->func = func;
143 item->context = context;
144 fixed_queue_enqueue(thread->work_queue, item);
145 return true;
146 }
147
thread_stop(thread_t * thread)148 void thread_stop(thread_t *thread) {
149 assert(thread != NULL);
150 reactor_stop(thread->reactor);
151 }
152
thread_set_priority(thread_t * thread,int priority)153 bool thread_set_priority(thread_t *thread, int priority) {
154 if (!thread)
155 return false;
156
157 const int rc = setpriority(PRIO_PROCESS, thread->tid, priority);
158 if (rc < 0) {
159 LOG_ERROR(LOG_TAG, "%s unable to set thread priority %d for tid %d, error %d",
160 __func__, priority, thread->tid, rc);
161 return false;
162 }
163
164 return true;
165 }
166
thread_is_self(const thread_t * thread)167 bool thread_is_self(const thread_t *thread) {
168 assert(thread != NULL);
169 return !!pthread_equal(pthread_self(), thread->pthread);
170 }
171
thread_get_reactor(const thread_t * thread)172 reactor_t *thread_get_reactor(const thread_t *thread) {
173 assert(thread != NULL);
174 return thread->reactor;
175 }
176
thread_name(const thread_t * thread)177 const char *thread_name(const thread_t *thread) {
178 assert(thread != NULL);
179 return thread->name;
180 }
181
run_thread(void * start_arg)182 static void *run_thread(void *start_arg) {
183 assert(start_arg != NULL);
184
185 struct start_arg *start = start_arg;
186 thread_t *thread = start->thread;
187
188 assert(thread != NULL);
189
190 if (prctl(PR_SET_NAME, (unsigned long)thread->name) == -1) {
191 LOG_ERROR(LOG_TAG, "%s unable to set thread name: %s", __func__, strerror(errno));
192 start->error = errno;
193 semaphore_post(start->start_sem);
194 return NULL;
195 }
196 thread->tid = gettid();
197
198 LOG_WARN(LOG_TAG, "%s: thread id %d, thread name %s started", __func__, thread->tid, thread->name);
199
200 semaphore_post(start->start_sem);
201
202 int fd = fixed_queue_get_dequeue_fd(thread->work_queue);
203 void *context = thread->work_queue;
204
205 reactor_object_t *work_queue_object = reactor_register(thread->reactor, fd, context, work_queue_read_cb, NULL);
206 reactor_start(thread->reactor);
207 reactor_unregister(work_queue_object);
208
209 // Make sure we dispatch all queued work items before exiting the thread.
210 // This allows a caller to safely tear down by enqueuing a teardown
211 // work item and then joining the thread.
212 size_t count = 0;
213 work_item_t *item = fixed_queue_try_dequeue(thread->work_queue);
214 while (item && count <= fixed_queue_capacity(thread->work_queue)) {
215 item->func(item->context);
216 osi_free(item);
217 item = fixed_queue_try_dequeue(thread->work_queue);
218 ++count;
219 }
220
221 if (count > fixed_queue_capacity(thread->work_queue))
222 LOG_DEBUG(LOG_TAG, "%s growing event queue on shutdown.", __func__);
223
224 LOG_WARN(LOG_TAG, "%s: thread id %d, thread name %s exited", __func__, thread->tid, thread->name);
225 return NULL;
226 }
227
work_queue_read_cb(void * context)228 static void work_queue_read_cb(void *context) {
229 assert(context != NULL);
230
231 fixed_queue_t *queue = (fixed_queue_t *)context;
232 work_item_t *item = fixed_queue_dequeue(queue);
233 item->func(item->context);
234 osi_free(item);
235 }
236