+++ /dev/null
-/*
- * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
- *
- * SPDX-License-Identifier: GPL-2.0-only
- *
- */
-
-#define _LGPL_SOURCE
-#include <assert.h>
-#include <fcntl.h>
-#include <limits.h>
-#include <stdlib.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
-#include <stdbool.h>
-
-#include <common/error.h>
-#include <common/defaults.h>
-#include <common/macros.h>
-#include <common/utils.h>
-
-#include "poll.h"
-
-/*
- * Maximum number of fd we can monitor.
- *
- * For epoll(7), /proc/sys/fs/epoll/max_user_watches (since Linux 2.6.28) will
- * be used for the maximum size of the poll set. If this interface is not
- * available, according to the manpage, the max_user_watches value is 1/25 (4%)
- * of the available low memory divided by the registration cost in bytes which
- * is 90 bytes on a 32-bit kernel and 160 bytes on a 64-bit kernel.
- *
- */
-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 lttng_poll_event *events,
- uint32_t new_size)
-{
- struct epoll_event *ptr;
-
- assert(events);
-
- ptr = realloc(events->events, new_size * sizeof(*ptr));
- if (ptr == NULL) {
- PERROR("realloc epoll add");
- goto error;
- }
- if (new_size > events->alloc_size) {
- /* Zero newly allocated memory */
- memset(ptr + events->alloc_size, 0,
- (new_size - events->alloc_size) * sizeof(*ptr));
- }
- events->events = ptr;
- events->alloc_size = new_size;
-
- return 0;
-
-error:
- return -1;
-}
-
-/*
- * Create epoll set and allocate returned events structure.
- */
-LTTNG_HIDDEN
-int compat_epoll_create(struct lttng_poll_event *events, int size, int flags)
-{
- int ret;
-
- if (events == NULL || size <= 0) {
- 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;
- }
-
- ret = compat_glibc_epoll_create(size, flags);
- if (ret < 0) {
- /* At this point, every error is fatal */
- PERROR("epoll_create1");
- goto error;
- }
-
- events->epfd = ret;
-
- /* This *must* be freed by using lttng_poll_free() */
- events->events = zmalloc(size * sizeof(struct epoll_event));
- if (events->events == NULL) {
- PERROR("zmalloc epoll set");
- goto error_close;
- }
-
- events->alloc_size = events->init_size = size;
- events->nb_fd = 0;
-
- return 0;
-
-error_close:
- ret = close(events->epfd);
- if (ret) {
- PERROR("close");
- }
-error:
- return -1;
-}
-
-/*
- * Add a fd to the epoll set with requesting events.
- */
-LTTNG_HIDDEN
-int compat_epoll_add(struct lttng_poll_event *events, int fd, uint32_t req_events)
-{
- int ret;
- struct epoll_event ev;
-
- if (events == NULL || events->events == NULL || fd < 0) {
- ERR("Bad compat epoll add arguments");
- goto error;
- }
-
- /*
- * Zero struct epoll_event to ensure all representations of its
- * union are zeroed.
- */
- memset(&ev, 0, sizeof(ev));
- ev.events = req_events;
- ev.data.fd = fd;
-
- ret = epoll_ctl(events->epfd, EPOLL_CTL_ADD, fd, &ev);
- if (ret < 0) {
- switch (errno) {
- case EEXIST:
- /* If exist, it's OK. */
- goto end;
- case ENOSPC:
- case EPERM:
- /* Print PERROR and goto end not failing. Show must go on. */
- PERROR("epoll_ctl ADD");
- goto end;
- default:
- PERROR("epoll_ctl ADD fatal");
- goto error;
- }
- }
-
- events->nb_fd++;
-
-end:
- return 0;
-
-error:
- return -1;
-}
-
-/*
- * Remove a fd from the epoll set.
- */
-LTTNG_HIDDEN
-int compat_epoll_del(struct lttng_poll_event *events, int fd)
-{
- int ret;
-
- if (events == NULL || fd < 0 || events->nb_fd == 0) {
- goto error;
- }
-
- ret = epoll_ctl(events->epfd, EPOLL_CTL_DEL, fd, NULL);
- if (ret < 0) {
- switch (errno) {
- case ENOENT:
- case EPERM:
- /* Print PERROR and goto end not failing. Show must go on. */
- PERROR("epoll_ctl DEL");
- goto end;
- default:
- PERROR("epoll_ctl DEL fatal");
- goto error;
- }
- }
-
- events->nb_fd--;
-
-end:
- return 0;
-
-error:
- return -1;
-}
-
-/*
- * Set an fd's events.
- */
-LTTNG_HIDDEN
-int compat_epoll_mod(struct lttng_poll_event *events, int fd, uint32_t req_events)
-{
- int ret;
- struct epoll_event ev;
-
- if (events == NULL || fd < 0 || events->nb_fd == 0) {
- goto error;
- }
-
- /*
- * Zero struct epoll_event to ensure all representations of its
- * union are zeroed.
- */
- memset(&ev, 0, sizeof(ev));
- ev.events = req_events;
- ev.data.fd = fd;
-
- ret = epoll_ctl(events->epfd, EPOLL_CTL_MOD, fd, &ev);
- if (ret < 0) {
- switch (errno) {
- case ENOENT:
- case EPERM:
- /* Print PERROR and goto end not failing. Show must go on. */
- PERROR("epoll_ctl MOD");
- goto end;
- default:
- PERROR("epoll_ctl MOD fatal");
- goto error;
- }
- }
-
-end:
- return 0;
-
-error:
- return -1;
-}
-
-/*
- * Wait on epoll set. This is a blocking call of timeout value.
- */
-LTTNG_HIDDEN
-int compat_epoll_wait(struct lttng_poll_event *events, int timeout,
- bool interruptible)
-{
- int ret;
- uint32_t new_size;
-
- if (events == NULL || events->events == NULL) {
- ERR("Wrong arguments in compat_epoll_wait");
- goto error;
- }
-
- if (events->nb_fd == 0) {
- errno = EINVAL;
- return -1;
- }
-
- /*
- * Resize if needed before waiting. We could either expand the array or
- * shrink it down. It's important to note that after this step, we are
- * ensured that the events argument of the epoll_wait call will be large
- * enough to hold every possible returned events.
- */
- new_size = 1U << utils_get_count_order_u32(events->nb_fd);
- if (new_size != events->alloc_size && new_size >= events->init_size) {
- ret = resize_poll_event(events, new_size);
- if (ret < 0) {
- /* ENOMEM problem at this point. */
- goto error;
- }
- }
-
- do {
- ret = epoll_wait(events->epfd, events->events, events->nb_fd, timeout);
- } while (!interruptible && ret == -1 && errno == EINTR);
- if (ret < 0) {
- if (errno != EINTR) {
- PERROR("epoll_wait");
- }
- goto error;
- }
-
- /*
- * Since the returned events are set sequentially in the "events" structure
- * we only need to return the epoll_wait value and iterate over it.
- */
- return ret;
-
-error:
- return -1;
-}
-
-/*
- * Setup poll set maximum size.
- */
-LTTNG_HIDDEN
-int compat_epoll_set_max_size(void)
-{
- int ret, fd, retval = 0;
- ssize_t size_ret;
- char buf[64];
-
- fd = open(COMPAT_EPOLL_PROC_PATH, O_RDONLY);
- if (fd < 0) {
- /*
- * Failing on opening [1] is not an error per see. [1] was
- * introduced in Linux 2.6.28 but epoll is available since
- * 2.5.44. Hence, goto end and set a default value without
- * setting an error return value.
- *
- * [1] /proc/sys/fs/epoll/max_user_watches
- */
- retval = 0;
- goto end;
- }
-
- size_ret = lttng_read(fd, buf, sizeof(buf));
- /*
- * Allow reading a file smaller than buf, but keep space for
- * final \0.
- */
- if (size_ret < 0 || size_ret >= sizeof(buf)) {
- PERROR("read set max size");
- retval = -1;
- goto end_read;
- }
- buf[size_ret] = '\0';
- poll_max_size = atoi(buf);
-end_read:
- ret = close(fd);
- if (ret) {
- PERROR("close");
- }
-end:
- if (!poll_max_size) {
- poll_max_size = DEFAULT_POLL_SIZE;
- }
- DBG("epoll set max size is %d", poll_max_size);
- return retval;
-}
projects / lttng-tools.git / blobdiff