/*
- * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
+ * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
+ * Copyright (C) 2019 Yannick Lamarre <ylamarre@efficios.com>
*
- * 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 _GNU_SOURCE
+#define _LGPL_SOURCE
#include <assert.h>
#include <stdlib.h>
#include <sys/resource.h>
#include <sys/time.h>
+#include <stdbool.h>
#include <common/defaults.h>
#include <common/error.h>
+#include <common/macros.h>
+#include <common/utils.h>
#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.
assert(array);
+ /* Refuse to resize the array more than the max size. */
+ if (new_size > poll_max_size) {
+ goto error;
+ }
+
ptr = realloc(array->events, new_size * sizeof(*ptr));
if (ptr == NULL) {
PERROR("realloc epoll add");
goto error;
}
+ if (new_size > array->alloc_size) {
+ /* Zero newly allocated memory */
+ memset(ptr + array->alloc_size, 0,
+ (new_size - array->alloc_size) * sizeof(*ptr));
+ }
array->events = ptr;
array->alloc_size = new_size;
wait = &events->wait;
wait->nb_fd = current->nb_fd;
- if (events->need_realloc) {
+ if (current->alloc_size != wait->alloc_size) {
ret = resize_poll_event(wait, current->alloc_size);
if (ret < 0) {
goto error;
memcpy(wait->events, current->events,
current->nb_fd * sizeof(*current->events));
- /* Update is done and realloc as well. */
+ /* Update is done. */
events->need_update = 0;
- events->need_realloc = 0;
return 0;
/*
* Create pollfd data structure.
*/
+LTTNG_HIDDEN
int compat_poll_create(struct lttng_poll_event *events, int size)
{
struct compat_poll_event_array *current, *wait;
goto error;
}
+ if (!poll_max_size) {
+ if (lttng_poll_set_max_size()) {
+ goto error;
+ }
+ }
+
/* Don't bust the limit here */
if (size > poll_max_size) {
size = poll_max_size;
/* Reset everything before begining the allocation. */
memset(events, 0, sizeof(struct lttng_poll_event));
- /* Ease our life a bit. */
current = &events->current;
wait = &events->wait;
/* This *must* be freed by using lttng_poll_free() */
wait->events = zmalloc(size * sizeof(struct pollfd));
if (wait->events == NULL) {
- perror("zmalloc struct pollfd");
+ PERROR("zmalloc struct pollfd");
goto error;
}
current->events = zmalloc(size * sizeof(struct pollfd));
if (current->events == NULL) {
- perror("zmalloc struct current pollfd");
+ PERROR("zmalloc struct current pollfd");
goto 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)
{
goto error;
}
- /* Ease our life a bit. */
current = &events->current;
/* Check if fd we are trying to add is already there. */
for (i = 0; i < current->nb_fd; i++) {
- /* Don't put back the fd we want to delete */
if (current->events[i].fd == fd) {
errno = EEXIST;
goto error;
}
}
- /* Check for a needed resize of the array. */
- if (current->nb_fd > current->alloc_size) {
- /* Expand it by a power of two of the current size. */
- new_size = current->alloc_size << 1UL;
+ /* Resize array if needed. */
+ new_size = 1U << utils_get_count_order_u32(current->nb_fd + 1);
+ if (new_size != current->alloc_size && new_size >= current->init_size) {
ret = resize_poll_event(current, new_size);
if (ret < 0) {
goto error;
}
- events->need_realloc = 1;
}
current->events[current->nb_fd].fd = fd;
}
/*
- * Remove a fd from the pollfd structure.
+ * Modify an fd's events..
*/
-int compat_poll_del(struct lttng_poll_event *events, int fd)
+LTTNG_HIDDEN
+int compat_poll_mod(struct lttng_poll_event *events, int fd,
+ uint32_t req_events)
{
- int new_size, i, count = 0, ret;
+ int i;
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) {
+ ERR("Bad compat poll mod arguments");
goto error;
}
- /* Ease our life a bit. */
current = &events->current;
- /* Safety check on size */
- if (new_size > poll_max_size) {
- new_size = poll_max_size;
+ for (i = 0; i < current->nb_fd; i++) {
+ if (current->events[i].fd == fd) {
+ current->events[i].events = req_events;
+ events->need_update = 1;
+ break;
+ }
}
- /* Check if we need to shrink it down. */
- if ((current->nb_fd << 1UL) <= current->alloc_size &&
- current->nb_fd >= current->init_size) {
- /*
- * Shrink if nb_fd multiplied by two is <= than the actual size and we
- * are above the initial size.
- */
- new_size = current->alloc_size >> 1UL;
- ret = resize_poll_event(current, new_size);
- if (ret < 0) {
- goto error;
- }
- events->need_realloc = 1;
+ /*
+ * The epoll flavor doesn't flag modifying a non-included FD as an
+ * error.
+ */
+
+ return 0;
+
+error:
+ return -1;
+}
+
+/*
+ * 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;
+ uint32_t new_size;
+ struct compat_poll_event_array *current;
+
+ if (events == NULL || events->current.nb_fd == 0 ||
+ events->current.events == NULL || fd < 0) {
+ goto error;
}
+ /* Ease our life a bit. */
+ current = &events->current;
+
for (i = 0; i < current->nb_fd; i++) {
/* Don't put back the fd we want to delete */
if (current->events[i].fd != fd) {
}
}
- current->nb_fd--;
+ /* 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
+ && current->nb_fd != 0) {
+ ret = resize_poll_event(current, new_size);
+ if (ret < 0) {
+ goto error;
+ }
+ }
+
events->need_update = 1;
+end:
return 0;
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;
+ int idle_pfd_index = 0;
+ size_t i;
if (events == NULL || events->current.events == NULL) {
ERR("poll wait arguments error");
if (events->current.nb_fd == 0) {
/* Return an invalid error to be consistent with epoll. */
errno = EINVAL;
+ events->wait.nb_fd = 0;
goto error;
}
}
}
- ret = poll(events->wait.events, events->wait.nb_fd, timeout);
+ do {
+ ret = poll(events->wait.events, events->wait.nb_fd, timeout);
+ } 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.
+ * 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.
*/
- return events->wait.nb_fd;
+ 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 (idle_pfd->revents != 0) {
+ swap_pfd = *current_pfd;
+ *current_pfd = *idle_pfd;
+ *idle_pfd = swap_pfd;
+ idle_pfd_index++;
+ }
+ }
+
+end:
+ return ret;
error:
return -1;
/*
* Setup poll set maximum size.
*/
-void compat_poll_set_max_size(void)
+LTTNG_HIDDEN
+int compat_poll_set_max_size(void)
{
- int ret;
+ int ret, retval = 0;
struct rlimit lim;
- /* Default value */
- poll_max_size = DEFAULT_POLL_SIZE;
-
ret = getrlimit(RLIMIT_NOFILE, &lim);
if (ret < 0) {
- perror("getrlimit poll RLIMIT_NOFILE");
- return;
+ PERROR("getrlimit poll RLIMIT_NOFILE");
+ retval = -1;
+ goto end;
}
poll_max_size = lim.rlim_cur;
+end:
if (poll_max_size == 0) {
- /* Extra precaution */
poll_max_size = DEFAULT_POLL_SIZE;
}
-
DBG("poll set max size set to %u", poll_max_size);
+ return retval;
}
projects / lttng-tools.git / blobdiff