X-Git-Url: https://git.liburcu.org/?a=blobdiff_plain;f=src%2Fcommon%2Fcompat%2Fcompat-poll.c;h=01de4f5489c578ebfcdd9caf50ca95920f8b1163;hb=1a8c9d1d35d4d71aac912f2dc2eceebb84b4eb8b;hp=0220b27854ab776294404c6c80e9a5608bfdeb54;hpb=22a7367148c238daf481e8e6756cdb76a73fd3a0;p=lttng-tools.git diff --git a/src/common/compat/compat-poll.c b/src/common/compat/compat-poll.c index 0220b2785..01de4f548 100644 --- a/src/common/compat/compat-poll.c +++ b/src/common/compat/compat-poll.c @@ -1,19 +1,9 @@ /* - * Copyright (C) 2011 - David Goulet - * Copyright (C) 2019 - Yannick Lamarre + * Copyright (C) 2011 David Goulet + * Copyright (C) 2019 Yannick Lamarre * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License, version 2 only, - * as published by the Free Software Foundation. + * SPDX-License-Identifier: GPL-2.0-only * - * This program is distributed in the hope that it will be useful, but WITHOUT - * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or - * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for - * more details. - * - * You should have received a copy of the GNU General Public License along - * with this program; if not, write to the Free Software Foundation, Inc., - * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #define _LGPL_SOURCE @@ -30,7 +20,14 @@ #include "poll.h" -unsigned int poll_max_size; + +/* + * Maximum number of fd we can monitor. + * + * For poll(2), the max fds must not exceed RLIMIT_NOFILE given by + * getrlimit(2). + */ +static unsigned int poll_max_size; /* * Resize the epoll events structure of the new size. @@ -103,6 +100,7 @@ error: /* * Create pollfd data structure. */ +LTTNG_HIDDEN int compat_poll_create(struct lttng_poll_event *events, int size) { struct compat_poll_event_array *current, *wait; @@ -155,6 +153,7 @@ error: /* * Add fd to pollfd data structure with requested events. */ +LTTNG_HIDDEN int compat_poll_add(struct lttng_poll_event *events, int fd, uint32_t req_events) { @@ -201,6 +200,7 @@ error: /* * Modify an fd's events.. */ +LTTNG_HIDDEN int compat_poll_mod(struct lttng_poll_event *events, int fd, uint32_t req_events) { @@ -237,6 +237,7 @@ error: /* * Remove a fd from the pollfd structure. */ +LTTNG_HIDDEN int compat_poll_del(struct lttng_poll_event *events, int fd) { int i, count = 0, ret; @@ -291,17 +292,17 @@ error: /* * Wait on poll() with timeout. Blocking call. */ -int compat_poll_wait(struct lttng_poll_event *events, int timeout) +LTTNG_HIDDEN +int compat_poll_wait(struct lttng_poll_event *events, int timeout, + bool interruptible) { int ret, active_fd_count; - int idle_pfd_index = 0; - size_t i; + size_t pos = 0, consecutive_entries = 0, non_idle_pos; if (events == NULL || events->current.events == NULL) { ERR("poll wait arguments error"); goto error; } - assert(events->current.nb_fd >= 0); if (events->current.nb_fd == 0) { /* Return an invalid error to be consistent with epoll. */ @@ -320,44 +321,47 @@ int compat_poll_wait(struct lttng_poll_event *events, int timeout) do { ret = poll(events->wait.events, events->wait.nb_fd, timeout); - } while (ret == -1 && errno == EINTR); + } while (!interruptible && ret == -1 && errno == EINTR); if (ret < 0) { - /* At this point, every error is fatal */ - PERROR("poll wait"); + if (errno != EINTR) { + PERROR("poll wait"); + } goto error; } active_fd_count = ret; /* - * Swap all active pollfd structs to the beginning of the - * array to emulate compat-epoll behaviour. This algorithm takes - * advantage of poll's returned value and the burst nature of active - * events on the file descriptors. The while loop guarantees that - * idle_pfd will always point to an idle fd. + * Move all active pollfd structs to the beginning of the + * array to emulate compat-epoll behaviour. */ if (active_fd_count == events->wait.nb_fd) { goto end; } - while (idle_pfd_index < active_fd_count && - events->wait.events[idle_pfd_index].revents != 0) { - idle_pfd_index++; - } - for (i = idle_pfd_index + 1; idle_pfd_index < active_fd_count; - i++) { - struct pollfd swap_pfd; - struct pollfd *idle_pfd = &events->wait.events[idle_pfd_index]; - struct pollfd *current_pfd = &events->wait.events[i]; - - if (ipfd->revents != 0) { - swap_pfd = *current_pfd; - *current_pfd = *idle_pfd; - *idle_pfd = swap_pfd; - idle_pfd_index++; + while (consecutive_entries != active_fd_count) { + struct pollfd *current = &events->wait.events[pos]; + struct pollfd idle_entry; + + if (current->revents != 0) { + consecutive_entries++; + pos++; + continue; } - } + non_idle_pos = pos; + + /* Look for next non-idle entry. */ + while (events->wait.events[++non_idle_pos].revents == 0); + + /* Swap idle and non-idle entries. */ + idle_entry = *current; + *current = events->wait.events[non_idle_pos]; + events->wait.events[non_idle_pos] = idle_entry; + + consecutive_entries++; + pos++; + } end: return ret; @@ -368,6 +372,7 @@ error: /* * Setup poll set maximum size. */ +LTTNG_HIDDEN int compat_poll_set_max_size(void) { int ret, retval = 0;