#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 <helper.h>
#include <lttng/ust-error.h>
#include <usterr-signal-safe.h>
+#include <lttng/ust-cancelstate.h>
#include "../liblttng-ust/compat.h"
*/
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.
+ * 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, thread_fd_tracking);
+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;
*/
void lttng_ust_fixup_fd_tracker_tls(void)
{
- asm volatile ("" : : "m" (URCU_TLS(thread_fd_tracking)));
+ asm volatile ("" : : "m" (URCU_TLS(ust_fd_mutex_nest)));
}
/*
void lttng_ust_lock_fd_tracker(void)
{
- int ret, oldstate;
+ sigset_t sig_all_blocked, orig_mask;
+ int ret;
- ret = pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldstate);
+ if (lttng_ust_cancelstate_disable_push()) {
+ ERR("lttng_ust_cancelstate_disable_push");
+ }
+ sigfillset(&sig_all_blocked);
+ ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_mask);
if (ret) {
- ERR("pthread_setcancelstate: %s", strerror(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);
+ }
+ ret = pthread_sigmask(SIG_SETMASK, &orig_mask, NULL);
+ if (ret) {
+ ERR("pthread_sigmask: %s", strerror(ret));
}
- 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);
- ust_safe_guard_saved_cancelstate = oldstate;
}
void lttng_ust_unlock_fd_tracker(void)
{
- int ret, newstate, oldstate;
+ sigset_t sig_all_blocked, orig_mask;
+ int ret;
- newstate = ust_safe_guard_saved_cancelstate;
- pthread_mutex_unlock(&ust_safe_guard_fd_mutex);
+ 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();
- URCU_TLS(thread_fd_tracking) = 0;
- ret = pthread_setcancelstate(newstate, &oldstate);
+ if (!--URCU_TLS(ust_fd_mutex_nest)) {
+ pthread_mutex_unlock(&ust_safe_guard_fd_mutex);
+ }
+ ret = pthread_sigmask(SIG_SETMASK, &orig_mask, NULL);
if (ret) {
- ERR("pthread_setcancelstate: %s", strerror(ret));
+ ERR("pthread_sigmask: %s", strerror(ret));
+ }
+ if (lttng_ust_cancelstate_disable_pop()) {
+ ERR("lttng_ust_cancelstate_disable_pop");
}
}
* constructors.
*/
lttng_ust_init_fd_tracker();
- assert(URCU_TLS(thread_fd_tracking));
+ assert(URCU_TLS(ust_fd_mutex_nest));
if (IS_FD_STD(fd)) {
ret = dup_std_fd(fd);
*/
lttng_ust_init_fd_tracker();
- assert(URCU_TLS(thread_fd_tracking));
+ assert(URCU_TLS(ust_fd_mutex_nest));
/* Not a valid fd. */
assert(IS_FD_VALID(fd));
/* Deleting an fd which was not set. */
* 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))
+ if (URCU_TLS(ust_fd_mutex_nest))
return close_cb(fd);
lttng_ust_lock_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))
+ if (URCU_TLS(ust_fd_mutex_nest))
return fclose_cb(stream);
fd = fileno(stream);
* 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)) {
+ if (URCU_TLS(ust_fd_mutex_nest)) {
for (i = lowfd; i < lttng_ust_max_fd; i++) {
if (close_cb(i) < 0) {
switch (errno) {
end:
return ret;
}
+
+/*
+ * Implement helper for close_range() override.
+ */
+int lttng_ust_safe_close_range_fd(unsigned int first, unsigned int last, int flags,
+ int (*close_range_cb)(unsigned int first, unsigned int last, int flags))
+{
+ int ret = 0, i;
+
+ lttng_ust_fixup_fd_tracker_tls();
+
+ /*
+ * Ensure the tracker is initialized when called from
+ * constructors.
+ */
+ lttng_ust_init_fd_tracker();
+
+ if (first > last || last > INT_MAX) {
+ ret = -1;
+ errno = EINVAL;
+ goto end;
+ }
+ /*
+ * If called from lttng-ust, we directly call close_range
+ * without validating whether the FD is part of the tracked set.
+ */
+ if (URCU_TLS(ust_fd_mutex_nest)) {
+ if (close_range_cb(first, last, flags) < 0) {
+ ret = -1;
+ goto end;
+ }
+ } else {
+ int last_check = last;
+
+ if (last > lttng_ust_max_fd)
+ last_check = lttng_ust_max_fd;
+ lttng_ust_lock_fd_tracker();
+ for (i = first; i <= last_check; i++) {
+ if (IS_FD_VALID(i) && IS_FD_SET(i, lttng_fd_set))
+ continue;
+ if (close_range_cb(i, i, flags) < 0) {
+ ret = -1;
+ /* propagate errno from close_range_cb. */
+ lttng_ust_unlock_fd_tracker();
+ goto end;
+ }
+ }
+ if (last > lttng_ust_max_fd) {
+ if (close_range_cb(lttng_ust_max_fd + 1, last, flags) < 0) {
+ ret = -1;
+ lttng_ust_unlock_fd_tracker();
+ goto end;
+ }
+ }
+ lttng_ust_unlock_fd_tracker();
+ }
+end:
+ return ret;
+}