#define _LGPL_SOURCE
#include <sys/types.h>
#include <sys/socket.h>
+#include <sys/prctl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <usterr-signal-safe.h>
#include "tracepoint-internal.h"
#include "ltt-tracer-core.h"
-#include "compat.h"
+#include "../libringbuffer/tlsfixup.h"
/*
* Has lttng ust comm constructor been called ?
int register_app_to_sessiond(int socket)
{
ssize_t ret;
+ int prctl_ret;
struct {
uint32_t major;
uint32_t minor;
reg_msg.uid = getuid();
reg_msg.gid = getgid();
reg_msg.bits_per_long = CAA_BITS_PER_LONG;
- lttng_ust_getprocname(reg_msg.name);
+ prctl_ret = prctl(PR_GET_NAME, (unsigned long) reg_msg.name, 0, 0, 0);
+ if (prctl_ret) {
+ ERR("Error executing prctl");
+ return -errno;
+ }
ret = ustcomm_send_unix_sock(socket, ®_msg, sizeof(reg_msg));
if (ret >= 0 && ret != sizeof(reg_msg))
//lur.ret_code = USTCOMM_SESSION_FAIL;
lur.ret_code = ret;
}
- switch (lum->cmd) {
- case LTTNG_UST_STREAM:
- /*
- * Special-case reply to send stream info.
- * Use lum.u output.
- */
- lur.u.stream.memory_map_size = *args.stream.memory_map_size;
- shm_fd = *args.stream.shm_fd;
- wait_fd = *args.stream.wait_fd;
- break;
- case LTTNG_UST_METADATA:
- case LTTNG_UST_CHANNEL:
- lur.u.channel.memory_map_size = *args.channel.memory_map_size;
- shm_fd = *args.channel.shm_fd;
- wait_fd = *args.channel.wait_fd;
- break;
- case LTTNG_UST_TRACER_VERSION:
- lur.u.version = lum->u.version;
- break;
- case LTTNG_UST_TRACEPOINT_LIST_GET:
- memcpy(&lur.u.tracepoint, &lum->u.tracepoint, sizeof(lur.u.tracepoint));
- break;
+ if (ret >= 0) {
+ switch (lum->cmd) {
+ case LTTNG_UST_STREAM:
+ /*
+ * Special-case reply to send stream info.
+ * Use lum.u output.
+ */
+ lur.u.stream.memory_map_size = *args.stream.memory_map_size;
+ shm_fd = *args.stream.shm_fd;
+ wait_fd = *args.stream.wait_fd;
+ break;
+ case LTTNG_UST_METADATA:
+ case LTTNG_UST_CHANNEL:
+ lur.u.channel.memory_map_size = *args.channel.memory_map_size;
+ shm_fd = *args.channel.shm_fd;
+ wait_fd = *args.channel.wait_fd;
+ break;
+ case LTTNG_UST_TRACER_VERSION:
+ lur.u.version = lum->u.version;
+ break;
+ case LTTNG_UST_TRACEPOINT_LIST_GET:
+ memcpy(&lur.u.tracepoint, &lum->u.tracepoint, sizeof(lur.u.tracepoint));
+ break;
+ }
}
ret = send_reply(sock, &lur);
if (ret < 0) {
}
static
-void cleanup_sock_info(struct sock_info *sock_info)
+void cleanup_sock_info(struct sock_info *sock_info, int exiting)
{
int ret;
if (sock_info->socket != -1) {
- ret = close(sock_info->socket);
+ ret = ustcomm_close_unix_sock(sock_info->socket);
if (ret) {
ERR("Error closing apps socket");
}
sock_info->root_handle = -1;
}
sock_info->constructor_sem_posted = 0;
- if (sock_info->wait_shm_mmap) {
+ /*
+ * wait_shm_mmap is used by listener threads outside of the
+ * ust lock, so we cannot tear it down ourselves, because we
+ * cannot join on these threads. Leave this task to the OS
+ * process exit.
+ */
+ if (!exiting && sock_info->wait_shm_mmap) {
ret = munmap(sock_info->wait_shm_mmap, sysconf(_SC_PAGE_SIZE));
if (ret) {
ERR("Error unmapping wait shm");
static
void wait_for_sessiond(struct sock_info *sock_info)
{
- int ret, oldtype;
+ int ret;
ust_lock();
if (lttng_ust_comm_should_quit) {
ust_unlock();
DBG("Waiting for %s apps sessiond", sock_info->name);
- /*
- * sys_futex does not honor pthread cancel requests. Set to
- * async.
- */
- ret = pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &oldtype);
- if (ret) {
- ERR("Error setting thread cancel type");
- }
/* Wait for futex wakeup */
if (uatomic_read((int32_t *) sock_info->wait_shm_mmap) == 0) {
ret = futex_async((int32_t *) sock_info->wait_shm_mmap,
}
}
}
- ret = pthread_setcanceltype(oldtype, &oldtype);
- if (ret) {
- ERR("Error setting thread cancel type");
- }
return;
quit:
}
if (sock_info->socket != -1) {
- ret = close(sock_info->socket);
+ ret = ustcomm_close_unix_sock(sock_info->socket);
if (ret) {
ERR("Error closing %s apps socket", sock_info->name);
}
if (uatomic_xchg(&initialized, 1) == 1)
return;
+ /*
+ * Fixup interdependency between TLS fixup mutex (which happens
+ * to be the dynamic linker mutex) and ust_lock, taken within
+ * the ust lock.
+ */
+ lttng_fixup_event_tls();
+ lttng_fixup_ringbuffer_tls();
+ lttng_fixup_vtid_tls();
+
/*
* We want precise control over the order in which we construct
* our sub-libraries vs starting to receive commands from
static
void lttng_ust_cleanup(int exiting)
{
- cleanup_sock_info(&global_apps);
+ cleanup_sock_info(&global_apps, exiting);
if (local_apps.allowed) {
- cleanup_sock_info(&local_apps);
+ cleanup_sock_info(&local_apps, exiting);
}
+ /*
+ * The teardown in this function all affect data structures
+ * accessed under the UST lock by the listener thread. This
+ * lock, along with the lttng_ust_comm_should_quit flag, ensure
+ * that none of these threads are accessing this data at this
+ * point.
+ */
lttng_ust_abi_exit();
lttng_ust_events_exit();
ltt_ring_buffer_client_discard_exit();
ERR("Error cancelling local ust listener thread");
}
}
- /* join threads */
- ret = pthread_join(global_apps.ust_listener, NULL);
- if (ret) {
- ERR("Error joining global ust listener thread");
- }
- if (local_apps.allowed) {
- ret = pthread_join(local_apps.ust_listener, NULL);
- if (ret) {
- ERR("Error joining local ust listener thread");
- }
- }
+ /*
+ * Do NOT join threads: use of sys_futex makes it impossible to
+ * join the threads without using async-cancel, but async-cancel
+ * is delivered by a signal, which could hit the target thread
+ * anywhere in its code path, including while the ust_lock() is
+ * held, causing a deadlock for the other thread. Let the OS
+ * cleanup the threads if there are stalled in a syscall.
+ */
lttng_ust_cleanup(1);
}
projects / lttng-ust.git / blobdiff