xref: /third_party/libuv/src/unix/async.c (revision e66f31c5) 
1/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
2 * Permission is hereby granted, free of charge, to any person obtaining a copy
3 * of this software and associated documentation files (the "Software"), to
4 * deal in the Software without restriction, including without limitation the
5 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
6 * sell copies of the Software, and to permit persons to whom the Software is
7 * furnished to do so, subject to the following conditions:
8 *
9 * The above copyright notice and this permission notice shall be included in
10 * all copies or substantial portions of the Software.
11 *
12 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
13 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
14 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
15 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
16 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
17 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
18 * IN THE SOFTWARE.
19 */
20
21/* This file contains both the uv__async internal infrastructure and the
22 * user-facing uv_async_t functions.
23 */
24
25#include "uv.h"
26#include "internal.h"
27#include "uv_log.h"
28
29#include <errno.h>
30#include <stdatomic.h>
31#include <stdio.h>  /* snprintf() */
32#include <assert.h>
33#include <stdlib.h>
34#include <string.h>
35#include <unistd.h>
36#include <sched.h>  /* sched_yield() */
37
38#ifdef __linux__
39#include <sys/eventfd.h>
40#endif
41
42#ifdef USE_FFRT
43#include "ffrt.h"
44#include "c/executor_task.h"
45#endif
46
47static void uv__async_send(uv_async_t* handle);
48static int uv__async_start(uv_loop_t* loop);
49
50
51int uv_async_init(uv_loop_t* loop, uv_async_t* handle, uv_async_cb async_cb) {
52  int err;
53
54  err = uv__async_start(loop);
55  if (err)
56    return err;
57
58  uv__handle_init(loop, (uv_handle_t*)handle, UV_ASYNC);
59  handle->async_cb = async_cb;
60  handle->pending = 0;
61
62  uv__queue_insert_tail(&loop->async_handles, &handle->queue);
63  uv__handle_start(handle);
64
65  return 0;
66}
67
68
69int uv_async_send(uv_async_t* handle) {
70  _Atomic int* pending;
71
72#ifdef USE_OHOS_DFX
73  if (handle == NULL) {
74    UV_LOGF("handle is NULL");
75    return -1;
76  }
77#endif
78
79  pending = (_Atomic int*) &handle->pending;
80
81
82  /* Do a cheap read first. */
83  if (atomic_load_explicit(pending, memory_order_relaxed) != 0)
84    return 0;
85
86  /* Wake up the other thread's event loop. */
87  if (atomic_exchange(pending, 1) != 0)
88    return 0;
89
90  /* Wake up the other thread's event loop. */
91  uv__async_send(handle);
92  return 0;
93}
94
95
96
97void uv__async_close(uv_async_t* handle) {
98  atomic_exchange((_Atomic int*) &handle->pending, 0);
99  uv__queue_remove(&handle->queue);
100  uv__handle_stop(handle);
101}
102
103
104static void uv__async_io(uv_loop_t* loop, uv__io_t* w, unsigned int events) {
105  char buf[1024];
106  ssize_t r;
107  struct uv__queue queue;
108  struct uv__queue* q;
109  uv_async_t* h;
110  _Atomic int *pending;
111
112  assert(w == &loop->async_io_watcher);
113
114  for (;;) {
115    r = read(w->fd, buf, sizeof(buf));
116
117    if (r == sizeof(buf))
118      continue;
119
120    if (r != -1)
121      break;
122
123    if (errno == EAGAIN || errno == EWOULDBLOCK)
124      break;
125
126    if (errno == EINTR)
127      continue;
128
129#ifdef PRINT_ERRNO_ABORT
130    UV_ERRNO_ABORT("errno is %d, loop addr is %zu, fd is %d (%s:%s:%d)",
131      errno, (size_t)loop, w->fd, __FILE__, __func__, __LINE__);
132#else
133    abort();
134#endif
135  }
136
137  uv__queue_move(&loop->async_handles, &queue);
138  while (!uv__queue_empty(&queue)) {
139    q = uv__queue_head(&queue);
140    h = uv__queue_data(q, uv_async_t, queue);
141
142    uv__queue_remove(q);
143    uv__queue_insert_tail(&loop->async_handles, q);
144
145    /* Atomically fetch and clear pending flag */
146    pending = (_Atomic int*) &h->pending;
147    if (atomic_exchange(pending, 0) == 0)
148      continue;
149
150    if (h->async_cb == NULL)
151      continue;
152
153    h->async_cb(h);
154  }
155}
156
157
158static void uv__async_send(uv_async_t* handle) {
159  const void* buf;
160  ssize_t len;
161  int fd;
162  int r;
163
164  uv_loop_t* loop = handle->loop;
165  if (loop == NULL) {
166    UV_LOGF("loop is NULL");
167    return;
168  }
169
170  buf = "";
171  len = 1;
172  fd = loop->async_wfd;
173
174#if defined(__linux__)
175  if (fd == -1) {
176    static const uint64_t val = 1;
177    buf = &val;
178    len = sizeof(val);
179    fd = loop->async_io_watcher.fd;  /* eventfd */
180  }
181#endif
182
183  do
184    r = write(fd, buf, len);
185  while (r == -1 && errno == EINTR && atomic_load_explicit((_Atomic int*) &handle->pending, memory_order_relaxed) == 1);
186
187  if (r == len)
188    return;
189
190  if (r == -1)
191    if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
192      return;
193
194#ifdef PRINT_ERRNO_ABORT
195    UV_ERRNO_ABORT("errno is %d, loop addr is %zu, fd is %d (%s:%s:%d)",
196      errno, (size_t)loop, fd, __FILE__, __func__, __LINE__);
197#else
198    abort();
199#endif
200}
201
202
203static int uv__async_start(uv_loop_t* loop) {
204  int pipefd[2];
205  int err;
206
207  if (loop->async_io_watcher.fd != -1)
208    return 0;
209
210#ifdef __linux__
211  err = eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK);
212  if (err < 0)
213    return UV__ERR(errno);
214
215  pipefd[0] = err;
216  pipefd[1] = -1;
217#ifdef USE_OHOS_DFX
218  fdsan_exchange_owner_tag(pipefd[0], 0, uv__get_addr_tag((void *)&loop->async_io_watcher));
219#endif
220#else
221  err = uv__make_pipe(pipefd, UV_NONBLOCK_PIPE);
222  if (err < 0)
223    return err;
224#endif
225
226  uv__io_init(&loop->async_io_watcher, uv__async_io, pipefd[0]);
227  uv__io_start(loop, &loop->async_io_watcher, POLLIN);
228  loop->async_wfd = pipefd[1];
229  UV_LOGI("open:%{public}zu, pipefd[0]:%{public}d", (size_t)loop, pipefd[0]);
230  return 0;
231}
232
233
234int uv__async_fork(uv_loop_t* loop) {
235  if (loop->async_io_watcher.fd == -1) /* never started */
236    return 0;
237
238  uv__async_stop(loop);
239
240  return uv__async_start(loop);
241}
242
243
244void uv__async_stop(uv_loop_t* loop) {
245  if (loop->async_io_watcher.fd == -1)
246    return;
247
248  if (loop->async_wfd != -1) {
249    if (loop->async_wfd != loop->async_io_watcher.fd) {
250      UV_LOGI("close:%{public}zu, async_wfd:%{public}d", (size_t)loop, loop->async_wfd);
251      uv__close(loop->async_wfd);
252    }
253    loop->async_wfd = -1;
254  }
255
256  uv__io_stop(loop, &loop->async_io_watcher, POLLIN);
257#ifdef USE_FFRT
258  if (ffrt_get_cur_task() != NULL) {
259    uv__epoll_ctl(loop->backend_fd, EPOLL_CTL_DEL, loop->async_io_watcher.fd, NULL);
260  }
261#endif
262
263#if defined(__linux__) && defined(USE_OHOS_DFX)
264  fdsan_close_with_tag(loop->async_io_watcher.fd, uv__get_addr_tag((void *)&loop->async_io_watcher));
265#else
266  uv__close(loop->async_io_watcher.fd);
267#endif
268  UV_LOGI("close:%{public}zu, async_io_wfd:%{public}d", (size_t)loop, loop->async_io_watcher.fd);
269  loop->async_io_watcher.fd = -1;
270}
271
272