+++ /dev/null
-/*
- * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
- * Copyright (C) 2019 Yannick Lamarre <ylamarre@efficios.com>
- *
- * SPDX-License-Identifier: GPL-2.0-only
- *
- */
-
-#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"
-
-
-/*
- * 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.
- *
- * 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 (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. */
- events->need_update = 0;
-
- return 0;
-
-error:
- return -1;
-}
-
-/*
- * Create pollfd data structure.
- */
-LTTNG_HIDDEN
-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;
- }
-
- 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));
-
- 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");
- goto error;
- }
-
- 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;
-
-error:
- return -1;
-}
-
-/*
- * 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)
-{
- int new_size, ret, i;
- struct compat_poll_event_array *current;
-
- if (events == NULL || events->current.events == NULL || fd < 0) {
- ERR("Bad compat poll add arguments");
- goto error;
- }
-
- current = &events->current;
-
- /* Check if fd we are trying to add is already there. */
- for (i = 0; i < current->nb_fd; i++) {
- if (current->events[i].fd == fd) {
- errno = EEXIST;
- goto error;
- }
- }
-
- /* 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;
- }
- }
-
- 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, current->nb_fd);
-
- return 0;
-
-error:
- return -1;
-}
-
-/*
- * Modify an fd's events..
- */
-LTTNG_HIDDEN
-int compat_poll_mod(struct lttng_poll_event *events, int fd,
- uint32_t req_events)
-{
- int i;
- struct compat_poll_event_array *current;
-
- if (events == NULL || events->current.nb_fd == 0 ||
- events->current.events == NULL || fd < 0) {
- ERR("Bad compat poll mod arguments");
- goto error;
- }
-
- current = &events->current;
-
- 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;
- }
- }
-
- /*
- * 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->events[count].fd = current->events[i].fd;
- current->events[count].events = current->events[i].events;
- 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
- && current->nb_fd != 0) {
- ret = resize_poll_event(current, new_size);
- if (ret < 0) {
- goto error;
- }
- }
-
- events->need_update = 1;
-
-end:
- return 0;
-
-error:
- return -1;
-}
-
-/*
- * Wait on poll() with timeout. Blocking call.
- */
-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;
-
- if (events == NULL || events->current.events == NULL) {
- ERR("poll wait arguments error");
- goto 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;
- }
-
- if (events->need_update) {
- ret = update_current_events(events);
- if (ret < 0) {
- errno = ENOMEM;
- goto error;
- }
- }
-
- do {
- ret = poll(events->wait.events, events->wait.nb_fd, timeout);
- } while (!interruptible && ret == -1 && errno == EINTR);
- if (ret < 0) {
- 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.
- */
- 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.
- */
-LTTNG_HIDDEN
-int compat_poll_set_max_size(void)
-{
- int ret, retval = 0;
- struct rlimit lim;
-
- ret = getrlimit(RLIMIT_NOFILE, &lim);
- if (ret < 0) {
- PERROR("getrlimit poll RLIMIT_NOFILE");
- retval = -1;
- goto end;
- }
-
- poll_max_size = lim.rlim_cur;
-end:
- if (poll_max_size == 0) {
- poll_max_size = DEFAULT_POLL_SIZE;
- }
- DBG("poll set max size set to %u", poll_max_size);
- return retval;
-}
projects / lttng-tools.git / blobdiff