usterr-signal-safe.h \
ust_snprintf.h \
ust-comm.h \
+ ust-fd.h \
lttng/ust-tid.h \
lttng/bitfield.h \
lttng/ust-dlfcn.h \
const char *enum_name);
void lttng_ust_dl_update(void *ip);
+void lttng_ust_fixup_fd_tracker_tls(void);
/* For backward compatibility. Leave those exported symbols in place. */
extern struct lttng_ctx *lttng_static_ctx;
--- /dev/null
+#ifndef _LTTNG_UST_FD_H
+#define _LTTNG_UST_FD_H
+
+/*
+ * Copyright (C) 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
+ */
+
+/*
+ * This header is meant for liblttng and libust internal use ONLY.
+ * These declarations should NOT be considered stable API.
+ */
+
+void lttng_ust_init_fd_tracker(void);
+void lttng_ust_add_fd_to_tracker(int fd);
+void lttng_ust_delete_fd_from_tracker(int fd);
+void lttng_ust_lock_fd_tracker(void);
+void lttng_ust_unlock_fd_tracker(void);
+
+int lttng_ust_safe_close_fd(int fd, int (*close_cb)(int));
+int lttng_ust_safe_closefrom_fd(int lowfd, int (*close_cb)(int));
+
+#endif /* _LTTNG_UST_FD_H */
noinst_LTLIBRARIES = liblttng-ust-comm.la
-liblttng_ust_comm_la_SOURCES = lttng-ust-comm.c
+liblttng_ust_comm_la_SOURCES = lttng-ust-comm.c lttng-ust-fd-tracker.c
#include <lttng/ust-ctl.h>
#include <ust-comm.h>
+#include <ust-fd.h>
#include <helper.h>
#include <lttng/ust-error.h>
#include <lttng/ust-events.h>
* ustcomm_connect_unix_sock
*
* Connect to unix socket using the path name.
+ *
+ * Caller handles FD tracker.
*/
int ustcomm_connect_unix_sock(const char *pathname, long timeout)
{
* ustcomm_close_unix_sock
*
* Shutdown cleanly a unix socket.
+ *
+ * Handles fd tracker internally.
*/
int ustcomm_close_unix_sock(int sock)
{
int ret;
+ lttng_ust_lock_fd_tracker();
ret = close(sock);
- if (ret < 0) {
+ if (!ret) {
+ lttng_ust_delete_fd_from_tracker(sock);
+ } else {
PERROR("close");
ret = -errno;
}
+ lttng_ust_unlock_fd_tracker();
return ret;
}
goto error_recv;
}
/* recv wakeup fd */
+ lttng_ust_lock_fd_tracker();
nr_fd = ustcomm_recv_fds_unix_sock(sock, &wakeup_fd, 1);
if (nr_fd <= 0) {
+ lttng_ust_unlock_fd_tracker();
if (nr_fd < 0) {
len = nr_fd;
goto error_recv;
}
}
*_wakeup_fd = wakeup_fd;
+ lttng_ust_add_fd_to_tracker(wakeup_fd);
+ lttng_ust_unlock_fd_tracker();
*_chan_data = chan_data;
return len;
int fds[2];
/* recv shm fd and wakeup fd */
+ lttng_ust_lock_fd_tracker();
len = ustcomm_recv_fds_unix_sock(sock, fds, 2);
if (len <= 0) {
+ lttng_ust_unlock_fd_tracker();
if (len < 0) {
ret = len;
goto error;
}
*shm_fd = fds[0];
*wakeup_fd = fds[1];
+ lttng_ust_add_fd_to_tracker(fds[0]);
+ lttng_ust_add_fd_to_tracker(fds[1]);
+ lttng_ust_unlock_fd_tracker();
return 0;
error:
--- /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(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;
+}
#include <lttng/ust-events.h>
#include <lttng/ust-version.h>
#include <lttng/tracepoint.h>
+#include <ust-fd.h>
#include "tracepoint-internal.h"
#include <usterr-signal-safe.h>
#include <helper.h>
{
int close_ret;
+ lttng_ust_lock_fd_tracker();
close_ret = close(wakeup_fd);
+ lttng_ust_unlock_fd_tracker();
if (close_ret) {
PERROR("close");
}
#include <lttng/ust-ctl.h>
#include <urcu/tls-compat.h>
#include <ust-comm.h>
+#include <ust-fd.h>
#include <usterr-signal-safe.h>
#include <helper.h>
#include "tracepoint-internal.h"
lttng_fixup_nest_count_tls();
lttng_fixup_procname_tls();
lttng_fixup_ust_mutex_nest_tls();
+ lttng_ust_fixup_fd_tracker_tls();
}
int lttng_get_notify_socket(void *owner)
goto error;
}
+ lttng_ust_lock_fd_tracker();
wait_shm_fd = get_wait_shm(sock_info, page_size);
if (wait_shm_fd < 0) {
+ lttng_ust_unlock_fd_tracker();
goto error;
}
+ lttng_ust_add_fd_to_tracker(wait_shm_fd);
+ lttng_ust_unlock_fd_tracker();
+
wait_shm_mmap = mmap(NULL, page_size, PROT_READ,
MAP_SHARED, wait_shm_fd, 0);
+
/* close shm fd immediately after taking the mmap reference */
+ lttng_ust_lock_fd_tracker();
ret = close(wait_shm_fd);
- if (ret) {
+ if (!ret) {
+ lttng_ust_delete_fd_from_tracker(wait_shm_fd);
+ } else {
PERROR("Error closing fd");
}
+ lttng_ust_unlock_fd_tracker();
+
if (wait_shm_mmap == MAP_FAILED) {
DBG("mmap error (can be caused by race with sessiond). Fallback to poll mode.");
goto error;
}
if (sock_info->socket != -1) {
+ /* FD tracker is updated by ustcomm_close_unix_sock() */
ret = ustcomm_close_unix_sock(sock_info->socket);
if (ret) {
ERR("Error closing %s ust cmd socket",
sock_info->socket = -1;
}
if (sock_info->notify_socket != -1) {
+ /* FD tracker is updated by ustcomm_close_unix_sock() */
ret = ustcomm_close_unix_sock(sock_info->notify_socket);
if (ret) {
ERR("Error closing %s ust notify socket",
sock_info->notify_socket = -1;
}
+ if (ust_lock()) {
+ goto quit;
+ }
+
/*
* Register. We need to perform both connect and sending
* registration message before doing the next connect otherwise
* first connect registration message.
*/
/* Connect cmd socket */
+ lttng_ust_lock_fd_tracker();
ret = ustcomm_connect_unix_sock(sock_info->sock_path,
get_connect_sock_timeout());
if (ret < 0) {
+ lttng_ust_unlock_fd_tracker();
DBG("Info: sessiond not accepting connections to %s apps socket", sock_info->name);
prev_connect_failed = 1;
- if (ust_lock()) {
- goto quit;
- }
-
/*
* If we cannot find the sessiond daemon, don't delay
* constructor execution.
ust_unlock();
goto restart;
}
+ lttng_ust_add_fd_to_tracker(ret);
+ lttng_ust_unlock_fd_tracker();
sock_info->socket = ret;
+ ust_unlock();
+ /*
+ * Unlock/relock ust lock because connect is blocking (with
+ * timeout). Don't delay constructors on the ust lock for too
+ * long.
+ */
if (ust_lock()) {
goto quit;
}
}
ust_unlock();
+ /*
+ * Unlock/relock ust lock because connect is blocking (with
+ * timeout). Don't delay constructors on the ust lock for too
+ * long.
+ */
+ if (ust_lock()) {
+ goto quit;
+ }
/* Connect notify socket */
+ lttng_ust_lock_fd_tracker();
ret = ustcomm_connect_unix_sock(sock_info->sock_path,
get_connect_sock_timeout());
if (ret < 0) {
+ lttng_ust_unlock_fd_tracker();
DBG("Info: sessiond not accepting connections to %s apps socket", sock_info->name);
prev_connect_failed = 1;
- if (ust_lock()) {
- goto quit;
- }
-
/*
* If we cannot find the sessiond daemon, don't delay
* constructor execution.
ust_unlock();
goto restart;
}
+ lttng_ust_add_fd_to_tracker(ret);
+ lttng_ust_unlock_fd_tracker();
sock_info->notify_socket = ret;
+ ust_unlock();
+ /*
+ * Unlock/relock ust lock because connect is blocking (with
+ * timeout). Don't delay constructors on the ust lock for too
+ * long.
+ */
+ if (ust_lock()) {
+ goto quit;
+ }
+
timeout = get_notify_sock_timeout();
if (timeout >= 0) {
/*
WARN("Unsupported timeout value %ld", timeout);
}
- if (ust_lock()) {
- goto quit;
- }
-
ret = register_to_sessiond(sock_info->notify_socket,
USTCTL_SOCKET_NOTIFY);
if (ret < 0) {
*/
init_usterr();
init_tracepoint();
+ lttng_ust_init_fd_tracker();
lttng_ust_clock_init();
lttng_ust_getcpu_init();
lttng_ust_statedump_init();
}
static void channel_free(struct channel *chan,
- struct lttng_ust_shm_handle *handle)
+ struct lttng_ust_shm_handle *handle,
+ int consumer)
{
channel_backend_free(&chan->backend, handle);
/* chan is freed by shm teardown */
- shm_object_table_destroy(handle->table);
+ shm_object_table_destroy(handle->table, consumer);
free(handle);
}
error_backend_init:
error_append:
- shm_object_table_destroy(handle->table);
+ shm_object_table_destroy(handle->table, 1);
error_table_alloc:
free(handle);
return NULL;
return handle;
error_table_object:
- shm_object_table_destroy(handle->table);
+ shm_object_table_destroy(handle->table, 0);
error_table_alloc:
free(handle);
return NULL;
}
static
-void channel_release(struct channel *chan, struct lttng_ust_shm_handle *handle)
+void channel_release(struct channel *chan, struct lttng_ust_shm_handle *handle,
+ int consumer)
{
- channel_free(chan, handle);
+ channel_free(chan, handle, consumer);
}
/**
* sessiond/consumer are keeping a reference on the shm file
* descriptor directly. No need to refcount.
*/
- channel_release(chan, handle);
+ channel_release(chan, handle, consumer);
return;
}
#include <lttng/align.h>
#include <limits.h>
#include <helper.h>
+#include <ust-fd.h>
/*
* Ensure we have the required amount of space available by writing 0
}
static
-void shmp_object_destroy(struct shm_object *obj)
+void shmp_object_destroy(struct shm_object *obj, int consumer)
{
switch (obj->type) {
case SHM_OBJECT_SHM:
PERROR("umnmap");
assert(0);
}
+
if (obj->shm_fd_ownership) {
- ret = close(obj->shm_fd);
- if (ret) {
- PERROR("close");
- assert(0);
+ /* Delete FDs only if called from app (not consumer). */
+ if (!consumer) {
+ lttng_ust_lock_fd_tracker();
+ ret = close(obj->shm_fd);
+ if (!ret) {
+ lttng_ust_delete_fd_from_tracker(obj->shm_fd);
+ } else {
+ PERROR("close");
+ assert(0);
+ }
+ lttng_ust_unlock_fd_tracker();
+ } else {
+ ret = close(obj->shm_fd);
+ if (ret) {
+ PERROR("close");
+ assert(0);
+ }
}
}
for (i = 0; i < 2; i++) {
if (obj->wait_fd[i] < 0)
continue;
- ret = close(obj->wait_fd[i]);
- if (ret) {
- PERROR("close");
- assert(0);
+ if (!consumer) {
+ lttng_ust_lock_fd_tracker();
+ ret = close(obj->wait_fd[i]);
+ if (!ret) {
+ lttng_ust_delete_fd_from_tracker(obj->wait_fd[i]);
+ } else {
+ PERROR("close");
+ assert(0);
+ }
+ lttng_ust_unlock_fd_tracker();
+ } else {
+ ret = close(obj->wait_fd[i]);
+ if (ret) {
+ PERROR("close");
+ assert(0);
+ }
}
}
break;
for (i = 0; i < 2; i++) {
if (obj->wait_fd[i] < 0)
continue;
- ret = close(obj->wait_fd[i]);
- if (ret) {
- PERROR("close");
- assert(0);
+ if (!consumer) {
+ lttng_ust_lock_fd_tracker();
+ ret = close(obj->wait_fd[i]);
+ if (!ret) {
+ lttng_ust_delete_fd_from_tracker(obj->wait_fd[i]);
+ } else {
+ PERROR("close");
+ assert(0);
+ }
+ lttng_ust_unlock_fd_tracker();
+ } else {
+ ret = close(obj->wait_fd[i]);
+ if (ret) {
+ PERROR("close");
+ assert(0);
+ }
}
}
free(obj->memory_map);
}
}
-void shm_object_table_destroy(struct shm_object_table *table)
+void shm_object_table_destroy(struct shm_object_table *table, int consumer)
{
int i;
for (i = 0; i < table->allocated_len; i++)
- shmp_object_destroy(&table->objects[i]);
+ shmp_object_destroy(&table->objects[i], consumer);
free(table);
}
/* mem ownership is passed to shm_object_table_append_mem(). */
struct shm_object *shm_object_table_append_mem(struct shm_object_table *table,
void *mem, size_t memory_map_size, int wakeup_fd);
-void shm_object_table_destroy(struct shm_object_table *table);
+void shm_object_table_destroy(struct shm_object_table *table, int consumer);
/*
* zalloc_shm - allocate memory within a shm object.
projects / lttng-ust.git / commitdiff
