diff options
Diffstat (limited to 'Utilities/cmlibuv/src/unix/posix-poll.c')
| -rw-r--r-- | Utilities/cmlibuv/src/unix/posix-poll.c | 374 |
1 files changed, 374 insertions, 0 deletions
diff --git a/Utilities/cmlibuv/src/unix/posix-poll.c b/Utilities/cmlibuv/src/unix/posix-poll.c new file mode 100644 index 0000000..0f4bf93 --- /dev/null +++ b/Utilities/cmlibuv/src/unix/posix-poll.c @@ -0,0 +1,374 @@ +/* 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__reallocf(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; + int user_timeout; + int reset_timeout; + + 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; + + if (uv__get_internal_fields(loop)->flags & UV_METRICS_IDLE_TIME) { + reset_timeout = 1; + user_timeout = timeout; + timeout = 0; + } else { + reset_timeout = 0; + } + + /* 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 (;;) { + /* Only need to set the provider_entry_time if timeout != 0. The function + * will return early if the loop isn't configured with UV_METRICS_IDLE_TIME. + */ + if (timeout != 0) + uv__metrics_set_provider_entry_time(loop); + + 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) { + if (reset_timeout != 0) { + timeout = user_timeout; + reset_timeout = 0; + if (timeout == -1) + continue; + if (timeout > 0) + goto update_timeout; + } + + assert(timeout != -1); + return; + } + + if (nfds == -1) { + if (errno != EINTR) + abort(); + + if (reset_timeout != 0) { + timeout = user_timeout; + reset_timeout = 0; + } + + 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 { + uv__metrics_update_idle_time(loop); + w->cb(loop, w, pe->revents); + } + + nevents++; + } + } + + if (reset_timeout != 0) { + timeout = user_timeout; + reset_timeout = 0; + } + + if (have_signals != 0) { + uv__metrics_update_idle_time(loop); + 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; +} |