X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=src%2Fcommon%2Fcompat%2Fcompat-poll.c;h=01de4f5489c578ebfcdd9caf50ca95920f8b1163;hb=1a8c9d1d35d4d71aac912f2dc2eceebb84b4eb8b;hp=b45b39dc6bdbd45daf69944316b1d663f1744867;hpb=8a2827515ad2b019753b84bcc3cb726af4ae428d;p=lttng-tools.git diff --git a/src/common/compat/compat-poll.c b/src/common/compat/compat-poll.c index b45b39dc6..01de4f548 100644 --- a/src/common/compat/compat-poll.c +++ b/src/common/compat/compat-poll.c @@ -1,18 +1,9 @@ /* - * Copyright (C) 2011 - David Goulet + * 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 @@ -29,7 +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. @@ -102,6 +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; @@ -154,6 +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) { @@ -200,14 +200,15 @@ error: /* * Modify an fd's events.. */ +LTTNG_HIDDEN int compat_poll_mod(struct lttng_poll_event *events, int fd, uint32_t req_events) { int i; - bool fd_found = false; struct compat_poll_event_array *current; - if (events == NULL || events->current.events == NULL || fd < 0) { + if (events == NULL || events->current.nb_fd == 0 || + events->current.events == NULL || fd < 0) { ERR("Bad compat poll mod arguments"); goto error; } @@ -216,16 +217,16 @@ int compat_poll_mod(struct lttng_poll_event *events, int fd, for (i = 0; i < current->nb_fd; i++) { if (current->events[i].fd == fd) { - fd_found = true; current->events[i].events = req_events; events->need_update = 1; break; } } - if (!fd_found) { - goto error; - } + /* + * The epoll flavor doesn't flag modifying a non-included FD as an + * error. + */ return 0; @@ -236,13 +237,15 @@ error: /* * Remove a fd from the pollfd structure. */ +LTTNG_HIDDEN int compat_poll_del(struct lttng_poll_event *events, int fd) { - int new_size, i, count = 0, ret; + int i, count = 0, ret; + uint32_t new_size; struct compat_poll_event_array *current; - if (events == NULL || events->current.events == NULL || fd < 0) { - ERR("Wrong arguments for poll del"); + if (events == NULL || events->current.nb_fd == 0 || + events->current.events == NULL || fd < 0) { goto error; } @@ -257,13 +260,20 @@ int compat_poll_del(struct lttng_poll_event *events, int fd) count++; } } + + /* The fd was not in our set, return no error as with epoll. */ + if (current->nb_fd == count) { + goto end; + } + /* No fd duplicate should be ever added into array. */ assert(current->nb_fd - 1 == count); current->nb_fd = count; /* Resize array if needed. */ new_size = 1U << utils_get_count_order_u32(current->nb_fd); - if (new_size != current->alloc_size && new_size >= current->init_size) { + if (new_size != current->alloc_size && new_size >= current->init_size + && current->nb_fd != 0) { ret = resize_poll_event(current, new_size); if (ret < 0) { goto error; @@ -272,6 +282,7 @@ int compat_poll_del(struct lttng_poll_event *events, int fd) events->need_update = 1; +end: return 0; error: @@ -281,15 +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; + int ret, active_fd_count; + 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. */ @@ -308,18 +321,49 @@ 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; + /* - * poll() should always iterate on all FDs since we handle the pollset in - * user space and after poll returns, we have to try every fd for a match. + * Move all active pollfd structs to the beginning of the + * array to emulate compat-epoll behaviour. */ - return events->wait.nb_fd; + if (active_fd_count == events->wait.nb_fd) { + goto end; + } + + 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; error: return -1; @@ -328,6 +372,7 @@ error: /* * Setup poll set maximum size. */ +LTTNG_HIDDEN int compat_poll_set_max_size(void) { int ret, retval = 0;