X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fcompat%2Fcompat-poll.c;h=4893768a098543815207c90283eb9591d97a3a4a;hp=50ef37472dc0a94db9eec258f21ce632f7d615d3;hb=53efb85a242809ed5ed21e9ab40effa696ecbc6f;hpb=0ba98ebc83bf874d34c8c84b164a6ad803e9de75 diff --git a/src/common/compat/compat-poll.c b/src/common/compat/compat-poll.c index 50ef37472..4893768a0 100644 --- a/src/common/compat/compat-poll.c +++ b/src/common/compat/compat-poll.c @@ -1,35 +1,111 @@ /* * Copyright (C) 2011 - David Goulet * - * This program is free software; you can redistribute it and/or modify it - * under the terms of the GNU General Public License as published by the Free - * Software Foundation; only version 2 of the License. + * 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. * * 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., 59 Temple - * Place - Suite 330, Boston, MA 02111-1307, USA. + * 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 +#include #include #include #include -#include +#include +#include +#include +#include #include "poll.h" unsigned int poll_max_size; +/* + * Resize the epoll events structure of the new size. + * + * Return 0 on success or else -1 with the current events pointer untouched. + */ +static int resize_poll_event(struct compat_poll_event_array *array, + uint32_t new_size) +{ + struct pollfd *ptr; + + 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; + + return 0; + +error: + return -1; +} + +/* + * Update events with the current events object. + */ +static int update_current_events(struct lttng_poll_event *events) +{ + int ret; + struct compat_poll_event_array *current, *wait; + + assert(events); + + current = &events->current; + wait = &events->wait; + + wait->nb_fd = current->nb_fd; + if (events->need_realloc) { + 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. */ + events->need_update = 0; + events->need_realloc = 0; + + return 0; + +error: + return -1; +} + /* * Create pollfd data structure. */ int compat_poll_create(struct lttng_poll_event *events, int size) { + struct compat_poll_event_array *current, *wait; + if (events == NULL || size <= 0) { ERR("Wrong arguments for poll create"); goto error; @@ -40,15 +116,29 @@ int compat_poll_create(struct lttng_poll_event *events, int 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() */ - events->events = zmalloc(size * sizeof(struct pollfd)); - if (events->events == NULL) { + wait->events = zmalloc(size * sizeof(struct pollfd)); + if (wait->events == NULL) { perror("zmalloc struct pollfd"); goto error; } - events->events_size = size; - events->nb_fd = 0; + wait->alloc_size = wait->init_size = size; + + current->events = zmalloc(size * sizeof(struct pollfd)); + if (current->events == NULL) { + perror("zmalloc struct current pollfd"); + goto error; + } + + current->alloc_size = current->init_size = size; return 0; @@ -62,31 +152,45 @@ error: int compat_poll_add(struct lttng_poll_event *events, int fd, uint32_t req_events) { - int new_size; - struct pollfd *ptr; + int new_size, ret, i; + struct compat_poll_event_array *current; - if (events == NULL || events->events == NULL || fd < 0) { + if (events == NULL || events->current.events == NULL || fd < 0) { ERR("Bad compat poll add arguments"); goto error; } - /* Reallocate pollfd structure by a factor of 2 if needed. */ - if (events->nb_fd >= events->events_size) { - new_size = 2 * events->events_size; - ptr = realloc(events->events, new_size * sizeof(struct pollfd)); - if (ptr == NULL) { - perror("realloc poll add"); + /* 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 = max_t(int, + 1U << utils_get_count_order_u32(current->nb_fd), + current->alloc_size << 1UL); + ret = resize_poll_event(current, new_size); + if (ret < 0) { goto error; } - events->events = ptr; - events->events_size = new_size; + events->need_realloc = 1; } - events->events[events->nb_fd].fd = fd; - events->events[events->nb_fd].events = req_events; - events->nb_fd++; + current->events[current->nb_fd].fd = fd; + current->events[current->nb_fd].events = req_events; + current->nb_fd++; + events->need_update = 1; - DBG("fd %d of %d added to pollfd", fd, events->nb_fd); + DBG("fd %d of %d added to pollfd", fd, current->nb_fd); return 0; @@ -99,42 +203,45 @@ error: */ int compat_poll_del(struct lttng_poll_event *events, int fd) { - int new_size, i, count = 0; - struct pollfd *old = NULL, *new = NULL; + int new_size, i, count = 0, ret; + struct compat_poll_event_array *current; - if (events == NULL || events->events == NULL || fd < 0) { + if (events == NULL || events->current.events == NULL || fd < 0) { ERR("Wrong arguments for poll del"); goto error; } - old = events->events; - new_size = events->events_size - 1; - - /* Safety check on size */ - if (new_size > poll_max_size) { - new_size = poll_max_size; - } - - new = zmalloc(new_size * sizeof(struct pollfd)); - if (new == NULL) { - perror("zmalloc poll del"); - goto error; + /* Ease our life a bit. */ + current = &events->current; + + /* 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 = max_t(int, + utils_get_count_order_u32(current->nb_fd) >> 1U, + current->alloc_size >> 1U); + ret = resize_poll_event(current, new_size); + if (ret < 0) { + goto error; + } + events->need_realloc = 1; } - for (i = 0; i < events->events_size; i++) { + for (i = 0; i < current->nb_fd; i++) { /* Don't put back the fd we want to delete */ - if (old[i].fd != fd) { - new[count].fd = old[i].fd; - new[count].events = old[i].events; + if (current->events[i].fd != fd) { + current->events[count].fd = current->events[i].fd; + current->events[count].events = current->events[i].events; count++; } } - events->events_size = new_size; - events->events = new; - events->nb_fd--; - - free(old); + current->nb_fd--; + events->need_update = 1; return 0; @@ -149,20 +256,37 @@ int compat_poll_wait(struct lttng_poll_event *events, int timeout) { int ret; - if (events == NULL || events->events == NULL || - events->events_size < events->nb_fd) { + if (events == NULL || events->current.events == NULL) { ERR("poll wait arguments error"); goto error; } - ret = poll(events->events, events->nb_fd, timeout); + if (events->current.nb_fd == 0) { + /* Return an invalid error to be consistent with epoll. */ + errno = EINVAL; + goto error; + } + + if (events->need_update) { + ret = update_current_events(events); + if (ret < 0) { + errno = ENOMEM; + goto error; + } + } + + ret = poll(events->wait.events, events->wait.nb_fd, timeout); if (ret < 0) { /* At this point, every error is fatal */ perror("poll wait"); goto error; } - return 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. + */ + return events->wait.nb_fd; error: return -1; @@ -177,7 +301,7 @@ void compat_poll_set_max_size(void) struct rlimit lim; /* Default value */ - poll_max_size = LTTNG_POLL_DEFAULT_SIZE; + poll_max_size = DEFAULT_POLL_SIZE; ret = getrlimit(RLIMIT_NOFILE, &lim); if (ret < 0) { @@ -186,9 +310,9 @@ void compat_poll_set_max_size(void) } poll_max_size = lim.rlim_cur; - if (poll_max_size <= 0) { + if (poll_max_size == 0) { /* Extra precaution */ - poll_max_size = LTTNG_POLL_DEFAULT_SIZE; + poll_max_size = DEFAULT_POLL_SIZE; } DBG("poll set max size set to %u", poll_max_size);