X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=liblttng-ust-comm%2Flttng-ust-fd-tracker.c;h=9659f349e54ac85a3afad50b2cfc2055abcfacfc;hb=HEAD;hp=c9b5fdc0250c72d3538fe6fc9d35b77c45ce3d31;hpb=864a1eda22ed99266509ac76451c6f27f91aa17e;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 c9b5fdc0..00000000
--- a/liblttng-ust-comm/lttng-ust-fd-tracker.c
+++ /dev/null
@@ -1,481 +0,0 @@
-/*
- * SPDX-License-Identifier: LGPL-2.1-only
- *
- * Copyright (C) 2016 Aravind HT <aravind.ht@gmail.com>
- * Copyright (C) 2016 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- */
-
-#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 <signal.h>
-#include <stdbool.h>
-#include <urcu/compiler.h>
-#include <urcu/tls-compat.h>
-#include <urcu/system.h>
-
-#include <ust-fd.h>
-#include <ust-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)
-#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.
- *
- * The ust_safe_guard_fd_mutex nests within the ust_mutex. This mutex
- * is also held across fork.
- */
-static pthread_mutex_t ust_safe_guard_fd_mutex = PTHREAD_MUTEX_INITIALIZER;
-
-/*
- * Cancel state when grabbing the ust_safe_guard_fd_mutex. Saved when
- * locking, restored on unlock. Protected by ust_safe_guard_fd_mutex.
- */
-static int ust_safe_guard_saved_cancelstate;
-
-/*
- * Track whether we are within lttng-ust or application, for close
- * system call override by LD_PRELOAD library. This also tracks whether
- * we are invoking close() from a signal handler nested on an
- * application thread.
- */
-static DEFINE_URCU_TLS(int, ust_fd_mutex_nest);
-
-/* 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(ust_fd_mutex_nest)));
-}
-
-/*
- * 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((&lttng_fd_set[i]));
-	CMM_STORE_SHARED(init_done, 1);
-}
-
-void lttng_ust_lock_fd_tracker(void)
-{
-	sigset_t sig_all_blocked, orig_mask;
-	int ret, oldstate;
-
-	ret = pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldstate);
-	if (ret) {
-		ERR("pthread_setcancelstate: %s", strerror(ret));
-	}
-	sigfillset(&sig_all_blocked);
-	ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_mask);
-	if (ret) {
-		ERR("pthread_sigmask: %s", strerror(ret));
-	}
-	if (!URCU_TLS(ust_fd_mutex_nest)++) {
-		/*
-		 * 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);
-		ust_safe_guard_saved_cancelstate = oldstate;
-	}
-	ret = pthread_sigmask(SIG_SETMASK, &orig_mask, NULL);
-	if (ret) {
-		ERR("pthread_sigmask: %s", strerror(ret));
-	}
-}
-
-void lttng_ust_unlock_fd_tracker(void)
-{
-	sigset_t sig_all_blocked, orig_mask;
-	int ret, newstate, oldstate;
-	bool restore_cancel = false;
-
-	sigfillset(&sig_all_blocked);
-	ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_mask);
-	if (ret) {
-		ERR("pthread_sigmask: %s", strerror(ret));
-	}
-	/*
-	 * Ensure the compiler don't move the store before the close()
-	 * call, in case close() would be marked as leaf.
-	 */
-	cmm_barrier();
-	if (!--URCU_TLS(ust_fd_mutex_nest)) {
-		newstate = ust_safe_guard_saved_cancelstate;
-		restore_cancel = true;
-		pthread_mutex_unlock(&ust_safe_guard_fd_mutex);
-	}
-	ret = pthread_sigmask(SIG_SETMASK, &orig_mask, NULL);
-	if (ret) {
-		ERR("pthread_sigmask: %s", strerror(ret));
-	}
-	if (restore_cancel) {
-		ret = pthread_setcancelstate(newstate, &oldstate);
-		if (ret) {
-			ERR("pthread_setcancelstate: %s", strerror(ret));
-		}
-	}
-}
-
-static int dup_std_fd(int fd)
-{
-	int ret, i;
-	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 (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 (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(ust_fd_mutex_nest));
-
-	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(ust_fd_mutex_nest));
-	/* 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(ust_fd_mutex_nest))
-		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(ust_fd_mutex_nest))
-		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(ust_fd_mutex_nest)) {
-		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;
-}