| /* Copyright Joyent, Inc. and other Node contributors. All rights reserved. |
| * Permission is hereby granted, free of charge, to any person obtaining a copy |
| * of this software and associated documentation files (the "Software"), to |
| * deal in the Software without restriction, including without limitation the |
| * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or |
| * sell copies of the Software, and to permit persons to whom the Software is |
| * furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be included in |
| * all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
| * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS |
| * IN THE SOFTWARE. |
| */ |
| |
| /* This file contains both the uv__async internal infrastructure and the |
| * user-facing uv_async_t functions. |
| */ |
| |
| #include "uv.h" |
| #include "internal.h" |
| #include "atomic-ops.h" |
| |
| #include <errno.h> |
| #include <stdio.h> /* snprintf() */ |
| #include <assert.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <unistd.h> |
| |
| static void uv__async_send(uv_loop_t* loop); |
| static int uv__async_start(uv_loop_t* loop); |
| static int uv__async_eventfd(void); |
| |
| |
| int uv_async_init(uv_loop_t* loop, uv_async_t* handle, uv_async_cb async_cb) { |
| int err; |
| |
| err = uv__async_start(loop); |
| if (err) |
| return err; |
| |
| uv__handle_init(loop, (uv_handle_t*)handle, UV_ASYNC); |
| handle->async_cb = async_cb; |
| handle->pending = 0; |
| |
| QUEUE_INSERT_TAIL(&loop->async_handles, &handle->queue); |
| uv__handle_start(handle); |
| |
| return 0; |
| } |
| |
| |
| int uv_async_send(uv_async_t* handle) { |
| /* Do a cheap read first. */ |
| if (ACCESS_ONCE(int, handle->pending) != 0) |
| return 0; |
| |
| if (cmpxchgi(&handle->pending, 0, 1) == 0) |
| uv__async_send(handle->loop); |
| |
| return 0; |
| } |
| |
| |
| void uv__async_close(uv_async_t* handle) { |
| QUEUE_REMOVE(&handle->queue); |
| uv__handle_stop(handle); |
| } |
| |
| |
| static void uv__async_io(uv_loop_t* loop, uv__io_t* w, unsigned int events) { |
| char buf[1024]; |
| ssize_t r; |
| QUEUE queue; |
| QUEUE* q; |
| uv_async_t* h; |
| |
| assert(w == &loop->async_io_watcher); |
| |
| for (;;) { |
| r = read(w->fd, buf, sizeof(buf)); |
| |
| if (r == sizeof(buf)) |
| continue; |
| |
| if (r != -1) |
| break; |
| |
| if (errno == EAGAIN || errno == EWOULDBLOCK) |
| break; |
| |
| if (errno == EINTR) |
| continue; |
| |
| abort(); |
| } |
| |
| QUEUE_MOVE(&loop->async_handles, &queue); |
| while (!QUEUE_EMPTY(&queue)) { |
| q = QUEUE_HEAD(&queue); |
| h = QUEUE_DATA(q, uv_async_t, queue); |
| |
| QUEUE_REMOVE(q); |
| QUEUE_INSERT_TAIL(&loop->async_handles, q); |
| |
| if (cmpxchgi(&h->pending, 1, 0) == 0) |
| continue; |
| |
| if (h->async_cb == NULL) |
| continue; |
| |
| h->async_cb(h); |
| } |
| } |
| |
| |
| static void uv__async_send(uv_loop_t* loop) { |
| const void* buf; |
| ssize_t len; |
| int fd; |
| int r; |
| |
| buf = ""; |
| len = 1; |
| fd = loop->async_wfd; |
| |
| #if defined(__linux__) |
| if (fd == -1) { |
| static const uint64_t val = 1; |
| buf = &val; |
| len = sizeof(val); |
| fd = loop->async_io_watcher.fd; /* eventfd */ |
| } |
| #endif |
| |
| do |
| r = write(fd, buf, len); |
| while (r == -1 && errno == EINTR); |
| |
| if (r == len) |
| return; |
| |
| if (r == -1) |
| if (errno == EAGAIN || errno == EWOULDBLOCK) |
| return; |
| |
| abort(); |
| } |
| |
| |
| static int uv__async_start(uv_loop_t* loop) { |
| int pipefd[2]; |
| int err; |
| |
| if (loop->async_io_watcher.fd != -1) |
| return 0; |
| |
| err = uv__async_eventfd(); |
| if (err >= 0) { |
| pipefd[0] = err; |
| pipefd[1] = -1; |
| } |
| else if (err == UV_ENOSYS) { |
| err = uv__make_pipe(pipefd, UV__F_NONBLOCK); |
| #if defined(__linux__) |
| /* Save a file descriptor by opening one of the pipe descriptors as |
| * read/write through the procfs. That file descriptor can then |
| * function as both ends of the pipe. |
| */ |
| if (err == 0) { |
| char buf[32]; |
| int fd; |
| |
| snprintf(buf, sizeof(buf), "/proc/self/fd/%d", pipefd[0]); |
| fd = uv__open_cloexec(buf, O_RDWR); |
| if (fd >= 0) { |
| uv__close(pipefd[0]); |
| uv__close(pipefd[1]); |
| pipefd[0] = fd; |
| pipefd[1] = fd; |
| } |
| } |
| #endif |
| } |
| |
| if (err < 0) |
| return err; |
| |
| uv__io_init(&loop->async_io_watcher, uv__async_io, pipefd[0]); |
| uv__io_start(loop, &loop->async_io_watcher, POLLIN); |
| loop->async_wfd = pipefd[1]; |
| |
| return 0; |
| } |
| |
| |
| int uv__async_fork(uv_loop_t* loop) { |
| if (loop->async_io_watcher.fd == -1) /* never started */ |
| return 0; |
| |
| uv__async_stop(loop); |
| |
| return uv__async_start(loop); |
| } |
| |
| |
| void uv__async_stop(uv_loop_t* loop) { |
| if (loop->async_io_watcher.fd == -1) |
| return; |
| |
| if (loop->async_wfd != -1) { |
| if (loop->async_wfd != loop->async_io_watcher.fd) |
| uv__close(loop->async_wfd); |
| loop->async_wfd = -1; |
| } |
| |
| uv__io_stop(loop, &loop->async_io_watcher, POLLIN); |
| uv__close(loop->async_io_watcher.fd); |
| loop->async_io_watcher.fd = -1; |
| } |
| |
| |
| static int uv__async_eventfd(void) { |
| #if defined(__linux__) |
| static int no_eventfd2; |
| static int no_eventfd; |
| int fd; |
| |
| if (no_eventfd2) |
| goto skip_eventfd2; |
| |
| fd = uv__eventfd2(0, UV__EFD_CLOEXEC | UV__EFD_NONBLOCK); |
| if (fd != -1) |
| return fd; |
| |
| if (errno != ENOSYS) |
| return UV__ERR(errno); |
| |
| no_eventfd2 = 1; |
| |
| skip_eventfd2: |
| |
| if (no_eventfd) |
| goto skip_eventfd; |
| |
| fd = uv__eventfd(0); |
| if (fd != -1) { |
| uv__cloexec(fd, 1); |
| uv__nonblock(fd, 1); |
| return fd; |
| } |
| |
| if (errno != ENOSYS) |
| return UV__ERR(errno); |
| |
| no_eventfd = 1; |
| |
| skip_eventfd: |
| |
| #endif |
| |
| return UV_ENOSYS; |
| } |