| /* Copyright libuv project 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. |
| */ |
| |
| #include "uv.h" |
| #include "internal.h" |
| |
| /* POSIX defines poll() as a portable way to wait on file descriptors. |
| * Here we maintain a dynamically sized array of file descriptors and |
| * events to pass as the first argument to poll(). |
| */ |
| |
| #include <assert.h> |
| #include <stddef.h> |
| #include <stdint.h> |
| #include <errno.h> |
| #include <unistd.h> |
| |
| int uv__platform_loop_init(uv_loop_t* loop) { |
| loop->poll_fds = NULL; |
| loop->poll_fds_used = 0; |
| loop->poll_fds_size = 0; |
| loop->poll_fds_iterating = 0; |
| return 0; |
| } |
| |
| void uv__platform_loop_delete(uv_loop_t* loop) { |
| uv__free(loop->poll_fds); |
| loop->poll_fds = NULL; |
| } |
| |
| int uv__io_fork(uv_loop_t* loop) { |
| uv__platform_loop_delete(loop); |
| return uv__platform_loop_init(loop); |
| } |
| |
| /* Allocate or dynamically resize our poll fds array. */ |
| static void uv__pollfds_maybe_resize(uv_loop_t* loop) { |
| size_t i; |
| size_t n; |
| struct pollfd* p; |
| |
| if (loop->poll_fds_used < loop->poll_fds_size) |
| return; |
| |
| n = loop->poll_fds_size ? loop->poll_fds_size * 2 : 64; |
| p = uv__realloc(loop->poll_fds, n * sizeof(*loop->poll_fds)); |
| if (p == NULL) |
| abort(); |
| |
| loop->poll_fds = p; |
| for (i = loop->poll_fds_size; i < n; i++) { |
| loop->poll_fds[i].fd = -1; |
| loop->poll_fds[i].events = 0; |
| loop->poll_fds[i].revents = 0; |
| } |
| loop->poll_fds_size = n; |
| } |
| |
| /* Primitive swap operation on poll fds array elements. */ |
| static void uv__pollfds_swap(uv_loop_t* loop, size_t l, size_t r) { |
| struct pollfd pfd; |
| pfd = loop->poll_fds[l]; |
| loop->poll_fds[l] = loop->poll_fds[r]; |
| loop->poll_fds[r] = pfd; |
| } |
| |
| /* Add a watcher's fd to our poll fds array with its pending events. */ |
| static void uv__pollfds_add(uv_loop_t* loop, uv__io_t* w) { |
| size_t i; |
| struct pollfd* pe; |
| |
| /* If the fd is already in the set just update its events. */ |
| assert(!loop->poll_fds_iterating); |
| for (i = 0; i < loop->poll_fds_used; ++i) { |
| if (loop->poll_fds[i].fd == w->fd) { |
| loop->poll_fds[i].events = w->pevents; |
| return; |
| } |
| } |
| |
| /* Otherwise, allocate a new slot in the set for the fd. */ |
| uv__pollfds_maybe_resize(loop); |
| pe = &loop->poll_fds[loop->poll_fds_used++]; |
| pe->fd = w->fd; |
| pe->events = w->pevents; |
| } |
| |
| /* Remove a watcher's fd from our poll fds array. */ |
| static void uv__pollfds_del(uv_loop_t* loop, int fd) { |
| size_t i; |
| assert(!loop->poll_fds_iterating); |
| for (i = 0; i < loop->poll_fds_used;) { |
| if (loop->poll_fds[i].fd == fd) { |
| /* swap to last position and remove */ |
| --loop->poll_fds_used; |
| uv__pollfds_swap(loop, i, loop->poll_fds_used); |
| loop->poll_fds[loop->poll_fds_used].fd = -1; |
| loop->poll_fds[loop->poll_fds_used].events = 0; |
| loop->poll_fds[loop->poll_fds_used].revents = 0; |
| /* This method is called with an fd of -1 to purge the invalidated fds, |
| * so we may possibly have multiples to remove. |
| */ |
| if (-1 != fd) |
| return; |
| } else { |
| /* We must only increment the loop counter when the fds do not match. |
| * Otherwise, when we are purging an invalidated fd, the value just |
| * swapped here from the previous end of the array will be skipped. |
| */ |
| ++i; |
| } |
| } |
| } |
| |
| |
| void uv__io_poll(uv_loop_t* loop, int timeout) { |
| sigset_t* pset; |
| sigset_t set; |
| uint64_t time_base; |
| uint64_t time_diff; |
| QUEUE* q; |
| uv__io_t* w; |
| size_t i; |
| unsigned int nevents; |
| int nfds; |
| int have_signals; |
| struct pollfd* pe; |
| int fd; |
| |
| if (loop->nfds == 0) { |
| assert(QUEUE_EMPTY(&loop->watcher_queue)); |
| return; |
| } |
| |
| /* Take queued watchers and add their fds to our poll fds array. */ |
| while (!QUEUE_EMPTY(&loop->watcher_queue)) { |
| q = QUEUE_HEAD(&loop->watcher_queue); |
| QUEUE_REMOVE(q); |
| QUEUE_INIT(q); |
| |
| w = QUEUE_DATA(q, uv__io_t, watcher_queue); |
| assert(w->pevents != 0); |
| assert(w->fd >= 0); |
| assert(w->fd < (int) loop->nwatchers); |
| |
| uv__pollfds_add(loop, w); |
| |
| w->events = w->pevents; |
| } |
| |
| /* Prepare a set of signals to block around poll(), if any. */ |
| pset = NULL; |
| if (loop->flags & UV_LOOP_BLOCK_SIGPROF) { |
| pset = &set; |
| sigemptyset(pset); |
| sigaddset(pset, SIGPROF); |
| } |
| |
| assert(timeout >= -1); |
| time_base = loop->time; |
| |
| /* Loop calls to poll() and processing of results. If we get some |
| * results from poll() but they turn out not to be interesting to |
| * our caller then we need to loop around and poll() again. |
| */ |
| for (;;) { |
| if (pset != NULL) |
| if (pthread_sigmask(SIG_BLOCK, pset, NULL)) |
| abort(); |
| nfds = poll(loop->poll_fds, (nfds_t)loop->poll_fds_used, timeout); |
| if (pset != NULL) |
| if (pthread_sigmask(SIG_UNBLOCK, pset, NULL)) |
| abort(); |
| |
| /* Update loop->time unconditionally. It's tempting to skip the update when |
| * timeout == 0 (i.e. non-blocking poll) but there is no guarantee that the |
| * operating system didn't reschedule our process while in the syscall. |
| */ |
| SAVE_ERRNO(uv__update_time(loop)); |
| |
| if (nfds == 0) { |
| assert(timeout != -1); |
| return; |
| } |
| |
| if (nfds == -1) { |
| if (errno != EINTR) |
| abort(); |
| |
| if (timeout == -1) |
| continue; |
| |
| if (timeout == 0) |
| return; |
| |
| /* Interrupted by a signal. Update timeout and poll again. */ |
| goto update_timeout; |
| } |
| |
| /* Tell uv__platform_invalidate_fd not to manipulate our array |
| * while we are iterating over it. |
| */ |
| loop->poll_fds_iterating = 1; |
| |
| /* Initialize a count of events that we care about. */ |
| nevents = 0; |
| have_signals = 0; |
| |
| /* Loop over the entire poll fds array looking for returned events. */ |
| for (i = 0; i < loop->poll_fds_used; i++) { |
| pe = loop->poll_fds + i; |
| fd = pe->fd; |
| |
| /* Skip invalidated events, see uv__platform_invalidate_fd. */ |
| if (fd == -1) |
| continue; |
| |
| assert(fd >= 0); |
| assert((unsigned) fd < loop->nwatchers); |
| |
| w = loop->watchers[fd]; |
| |
| if (w == NULL) { |
| /* File descriptor that we've stopped watching, ignore. */ |
| uv__platform_invalidate_fd(loop, fd); |
| continue; |
| } |
| |
| /* Filter out events that user has not requested us to watch |
| * (e.g. POLLNVAL). |
| */ |
| pe->revents &= w->pevents | POLLERR | POLLHUP; |
| |
| if (pe->revents != 0) { |
| /* Run signal watchers last. */ |
| if (w == &loop->signal_io_watcher) { |
| have_signals = 1; |
| } else { |
| w->cb(loop, w, pe->revents); |
| } |
| |
| nevents++; |
| } |
| } |
| |
| if (have_signals != 0) |
| loop->signal_io_watcher.cb(loop, &loop->signal_io_watcher, POLLIN); |
| |
| loop->poll_fds_iterating = 0; |
| |
| /* Purge invalidated fds from our poll fds array. */ |
| uv__pollfds_del(loop, -1); |
| |
| if (have_signals != 0) |
| return; /* Event loop should cycle now so don't poll again. */ |
| |
| if (nevents != 0) |
| return; |
| |
| if (timeout == 0) |
| return; |
| |
| if (timeout == -1) |
| continue; |
| |
| update_timeout: |
| assert(timeout > 0); |
| |
| time_diff = loop->time - time_base; |
| if (time_diff >= (uint64_t) timeout) |
| return; |
| |
| timeout -= time_diff; |
| } |
| } |
| |
| /* Remove the given fd from our poll fds array because no one |
| * is interested in its events anymore. |
| */ |
| void uv__platform_invalidate_fd(uv_loop_t* loop, int fd) { |
| size_t i; |
| |
| assert(fd >= 0); |
| |
| if (loop->poll_fds_iterating) { |
| /* uv__io_poll is currently iterating. Just invalidate fd. */ |
| for (i = 0; i < loop->poll_fds_used; i++) |
| if (loop->poll_fds[i].fd == fd) { |
| loop->poll_fds[i].fd = -1; |
| loop->poll_fds[i].events = 0; |
| loop->poll_fds[i].revents = 0; |
| } |
| } else { |
| /* uv__io_poll is not iterating. Delete fd from the set. */ |
| uv__pollfds_del(loop, fd); |
| } |
| } |
| |
| /* Check whether the given fd is supported by poll(). */ |
| int uv__io_check_fd(uv_loop_t* loop, int fd) { |
| struct pollfd p[1]; |
| int rv; |
| |
| p[0].fd = fd; |
| p[0].events = POLLIN; |
| |
| do |
| rv = poll(p, 1, 0); |
| while (rv == -1 && (errno == EINTR || errno == EAGAIN)); |
| |
| if (rv == -1) |
| return UV__ERR(errno); |
| |
| if (p[0].revents & POLLNVAL) |
| return UV_EINVAL; |
| |
| return 0; |
| } |