X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust-comm%2Flttng-ust-fd-tracker.c;h=9659f349e54ac85a3afad50b2cfc2055abcfacfc;hb=HEAD;hp=329339f98a038736fe528bc856bdeff1737b4c2b;hpb=f5c453e975e5d417590b9a1be2a9f8504db063c0;p=lttng-ust.git diff --git a/liblttng-ust-comm/lttng-ust-fd-tracker.c b/liblttng-ust-comm/lttng-ust-fd-tracker.c deleted file mode 100644 index 329339f9..00000000 --- a/liblttng-ust-comm/lttng-ust-fd-tracker.c +++ /dev/null @@ -1,440 +0,0 @@ -/* - * Copyright (C) 2016 - Aravind HT - * 2016 - Mathieu Desnoyers - * - * 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 -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -#include -#include -#include -#include - -#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) -#define IS_FD_STD(fd) (IS_FD_VALID(fd) && (fd) <= STDERR_FILENO) - -/* 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(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; -static int init_done; - -/* - * 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; - - if (CMM_LOAD_SHARED(init_done)) - return; - - 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])); - CMM_STORE_SHARED(init_done, 1); -} - -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; -} - -static int dup_std_fd(int fd) -{ - int ret; - int fd_to_close[STDERR_FILENO + 1]; - int fd_to_close_count = 0; - int dup_cmd = F_DUPFD; /* Default command */ - int fd_valid = -1; - - if (!(IS_FD_STD(fd))) { - /* Should not be here */ - ret = -1; - goto error; - } - - /* Check for FD_CLOEXEC flag */ - ret = fcntl(fd, F_GETFD); - if (ret < 0) { - PERROR("fcntl on f_getfd"); - ret = -1; - goto error; - } - - if (ret & FD_CLOEXEC) { - dup_cmd = F_DUPFD_CLOEXEC; - } - - /* Perform dup */ - for (int i = 0; i < STDERR_FILENO + 1; i++) { - ret = fcntl(fd, dup_cmd, 0); - if (ret < 0) { - PERROR("fcntl dup fd"); - goto error; - } - - if (!(IS_FD_STD(ret))) { - /* fd is outside of STD range, use it. */ - fd_valid = ret; - /* Close fd received as argument. */ - fd_to_close[i] = fd; - fd_to_close_count++; - break; - } - - fd_to_close[i] = ret; - fd_to_close_count++; - } - - /* Close intermediary fds */ - for (int i = 0; i < fd_to_close_count; i++) { - ret = close(fd_to_close[i]); - if (ret) { - PERROR("close on temporary fd: %d.", fd_to_close[i]); - /* - * Not using an abort here would yield a complicated - * error handling for the caller. If a failure occurs - * here, the system is already in a bad state. - */ - abort(); - } - } - - ret = fd_valid; -error: - return ret; -} - -/* - * Needs to be called with ust_safe_guard_fd_mutex held when opening the fd. - * Has strict checking of fd validity. - * - * If fd <= 2, dup the fd until fd > 2. This enables us to bypass - * problems that can be encountered if UST uses stdin, stdout, stderr - * fds for internal use (daemon etc.). This can happen if the - * application closes either of those file descriptors. Intermediary fds - * are closed as needed. - * - * Return -1 on error. - * - */ -int lttng_ust_add_fd_to_tracker(int fd) -{ - int ret; - /* - * Ensure the tracker is initialized when called from - * constructors. - */ - lttng_ust_init_fd_tracker(); - assert(URCU_TLS(thread_fd_tracking)); - - if (IS_FD_STD(fd)) { - ret = dup_std_fd(fd); - if (ret < 0) { - goto error; - } - fd = ret; - } - - /* 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); - return fd; -error: - return ret; -} - -/* - * 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) -{ - /* - * Ensure the tracker is initialized when called from - * constructors. - */ - lttng_ust_init_fd_tracker(); - - 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(); - - /* - * Ensure the tracker is initialized when called from - * constructors. - */ - lttng_ust_init_fd_tracker(); - - /* - * 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; -} - -/* - * Interface allowing applications to close arbitrary streams. - * 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_fclose_stream(FILE *stream, int (*fclose_cb)(FILE *stream)) -{ - int ret = 0, fd; - - lttng_ust_fixup_fd_tracker_tls(); - - /* - * Ensure the tracker is initialized when called from - * constructors. - */ - lttng_ust_init_fd_tracker(); - - /* - * If called from lttng-ust, we directly call fclose without - * validating whether the FD is part of the tracked set. - */ - if (URCU_TLS(thread_fd_tracking)) - return fclose_cb(stream); - - fd = fileno(stream); - - lttng_ust_lock_fd_tracker(); - if (IS_FD_VALID(fd) && IS_FD_SET(fd, lttng_fd_set)) { - ret = -1; - errno = EBADF; - } else { - ret = fclose_cb(stream); - } - 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(); - - /* - * Ensure the tracker is initialized when called from - * constructors. - */ - lttng_ust_init_fd_tracker(); - - 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; -}