+++ /dev/null
-/*
- * Copyright (C) 2016 - Aravind HT <aravind.ht@gmail.com>
- * 2016 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; only
- * version 2.1 of the License.
- *
- * This library 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
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-#define _GNU_SOURCE
-#include <limits.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/types.h>
-#include <unistd.h>
-#include <assert.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <sys/select.h>
-#include <sys/resource.h>
-#include <sys/time.h>
-#include <fcntl.h>
-#include <pthread.h>
-#include <urcu/compiler.h>
-#include <urcu/tls-compat.h>
-
-#include <ust-fd.h>
-#include <helper.h>
-#include <lttng/ust-error.h>
-#include <usterr-signal-safe.h>
-
-#include "../liblttng-ust/compat.h"
-
-/* Operations on the fd set. */
-#define IS_FD_VALID(fd) ((fd) >= 0 && (fd) < lttng_ust_max_fd)
-#define GET_FD_SET_FOR_FD(fd, fd_sets) (&((fd_sets)[(fd) / FD_SETSIZE]))
-#define CALC_INDEX_TO_SET(fd) ((fd) % FD_SETSIZE)
-
-/* Check fd validity before calling these. */
-#define ADD_FD_TO_SET(fd, fd_sets) \
- FD_SET(CALC_INDEX_TO_SET(fd), GET_FD_SET_FOR_FD(fd, fd_sets))
-#define IS_FD_SET(fd, fd_sets) \
- FD_ISSET(CALC_INDEX_TO_SET(fd), GET_FD_SET_FOR_FD(fd, fd_sets))
-#define DEL_FD_FROM_SET(fd, fd_sets) \
- FD_CLR(CALC_INDEX_TO_SET(fd), GET_FD_SET_FOR_FD(fd, fd_sets))
-
-/*
- * Protect the lttng_fd_set. Nests within the ust_lock, and therefore
- * within the libc dl lock. Therefore, we need to fixup the TLS before
- * nesting into this lock.
- */
-static pthread_mutex_t ust_safe_guard_fd_mutex = PTHREAD_MUTEX_INITIALIZER;
-/*
- * Track whether we are within lttng-ust or application, for close
- * system call override by LD_PRELOAD library.
- */
-static DEFINE_URCU_TLS_IE(int, thread_fd_tracking);
-
-/* fd_set used to book keep fd being used by lttng-ust. */
-static fd_set *lttng_fd_set;
-static int lttng_ust_max_fd;
-static int num_fd_sets;
-
-/*
- * Force a read (imply TLS fixup for dlopen) of TLS variables.
- */
-void lttng_ust_fixup_fd_tracker_tls(void)
-{
- asm volatile ("" : : "m" (URCU_TLS(thread_fd_tracking)));
-}
-
-/*
- * Allocate the fd set array based on the hard limit set for this
- * process. This will be called during the constructor execution
- * and will also be called in the child after fork via lttng_ust_init.
- */
-void lttng_ust_init_fd_tracker(void)
-{
- struct rlimit rlim;
- int i;
-
- memset(&rlim, 0, sizeof(rlim));
- /* Get the current possible max number of fd for this process. */
- if (getrlimit(RLIMIT_NOFILE, &rlim) < 0)
- abort();
- /*
- * FD set array size determined using the hard limit. Even if
- * the process wishes to increase its limit using setrlimit, it
- * can only do so with the softlimit which will be less than the
- * hard limit.
- */
- lttng_ust_max_fd = rlim.rlim_max;
- num_fd_sets = lttng_ust_max_fd / FD_SETSIZE;
- if (lttng_ust_max_fd % FD_SETSIZE)
- ++num_fd_sets;
- if (lttng_fd_set != NULL) {
- free(lttng_fd_set);
- lttng_fd_set = NULL;
- }
- lttng_fd_set = malloc(num_fd_sets * (sizeof(fd_set)));
- if (!lttng_fd_set)
- abort();
- for (i = 0; i < num_fd_sets; i++)
- FD_ZERO((<tng_fd_set[i]));
-}
-
-void lttng_ust_lock_fd_tracker(void)
-{
- URCU_TLS(thread_fd_tracking) = 1;
- /*
- * Ensure the compiler don't move the store after the close()
- * call in case close() would be marked as leaf.
- */
- cmm_barrier();
- pthread_mutex_lock(&ust_safe_guard_fd_mutex);
-}
-
-void lttng_ust_unlock_fd_tracker(void)
-{
- pthread_mutex_unlock(&ust_safe_guard_fd_mutex);
- /*
- * Ensure the compiler don't move the store before the close()
- * call, in case close() would be marked as leaf.
- */
- cmm_barrier();
- URCU_TLS(thread_fd_tracking) = 0;
-}
-
-/*
- * Needs to be called with ust_safe_guard_fd_mutex held when opening the fd.
- * Has strict checking of fd validity.
- */
-void lttng_ust_add_fd_to_tracker(int fd)
-{
- assert(URCU_TLS(thread_fd_tracking));
- /* Trying to add an fd which we can not accommodate. */
- assert(IS_FD_VALID(fd));
- /* Setting an fd thats already set. */
- assert(!IS_FD_SET(fd, lttng_fd_set));
-
- ADD_FD_TO_SET(fd, lttng_fd_set);
-}
-
-/*
- * Needs to be called with ust_safe_guard_fd_mutex held when opening the fd.
- * Has strict checking for fd validity.
- */
-void lttng_ust_delete_fd_from_tracker(int fd)
-{
- assert(URCU_TLS(thread_fd_tracking));
- /* Not a valid fd. */
- assert(IS_FD_VALID(fd));
- /* Deleting an fd which was not set. */
- assert(IS_FD_SET(fd, lttng_fd_set));
-
- DEL_FD_FROM_SET(fd, lttng_fd_set);
-}
-
-/*
- * Interface allowing applications to close arbitrary file descriptors.
- * We check if it is owned by lttng-ust, and return -1, errno=EBADF
- * instead of closing it if it is the case.
- */
-int lttng_ust_safe_close_fd(int fd, int (*close_cb)(int fd))
-{
- int ret = 0;
-
- lttng_ust_fixup_fd_tracker_tls();
-
- /*
- * If called from lttng-ust, we directly call close without
- * validating whether the FD is part of the tracked set.
- */
- if (URCU_TLS(thread_fd_tracking))
- return close_cb(fd);
-
- lttng_ust_lock_fd_tracker();
- if (IS_FD_VALID(fd) && IS_FD_SET(fd, lttng_fd_set)) {
- ret = -1;
- errno = EBADF;
- } else {
- ret = close_cb(fd);
- }
- lttng_ust_unlock_fd_tracker();
-
- return ret;
-}
-
-#ifdef __OpenBSD__
-static void set_close_success(int *p)
-{
- *p = 1;
-}
-static int test_close_success(const int *p)
-{
- return *p;
-}
-#else
-static void set_close_success(int *p __attribute__((unused)))
-{
-}
-static int test_close_success(const int *p __attribute__((unused)))
-{
- return 1;
-}
-#endif
-
-/*
- * Implement helper for closefrom() override.
- */
-int lttng_ust_safe_closefrom_fd(int lowfd, int (*close_cb)(int fd))
-{
- int ret = 0, close_success = 0, i;
-
- lttng_ust_fixup_fd_tracker_tls();
-
- if (lowfd < 0) {
- /*
- * NetBSD return EBADF if fd is invalid.
- */
- errno = EBADF;
- ret = -1;
- goto end;
- }
- /*
- * If called from lttng-ust, we directly call close without
- * validating whether the FD is part of the tracked set.
- */
- if (URCU_TLS(thread_fd_tracking)) {
- for (i = lowfd; i < lttng_ust_max_fd; i++) {
- if (close_cb(i) < 0) {
- switch (errno) {
- case EBADF:
- continue;
- case EINTR:
- default:
- ret = -1;
- goto end;
- }
- }
- set_close_success(&close_success);
- }
- } else {
- lttng_ust_lock_fd_tracker();
- for (i = lowfd; i < lttng_ust_max_fd; i++) {
- if (IS_FD_VALID(i) && IS_FD_SET(i, lttng_fd_set))
- continue;
- if (close_cb(i) < 0) {
- switch (errno) {
- case EBADF:
- continue;
- case EINTR:
- default:
- ret = -1;
- lttng_ust_unlock_fd_tracker();
- goto end;
- }
- }
- set_close_success(&close_success);
- }
- lttng_ust_unlock_fd_tracker();
- }
- if (!test_close_success(&close_success)) {
- /*
- * OpenBSD return EBADF if fd is greater than all open
- * file descriptors.
- */
- ret = -1;
- errno = EBADF;
- }
-end:
- return ret;
-}
projects / lttng-ust.git / blobdiff