#include <lttng-ust-comm.h>
#include <ust/usterr-signal-safe.h>
#include <pthread.h>
+#include <assert.h>
+
+/*
+ * communication thread mutex. Held when handling a command, also held
+ * by fork() to deal with removal of threads, and by exit path.
+ */
+static pthread_mutex_t lttng_ust_comm_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+/* Should the ust comm thread quit ? */
+static int lttng_ust_comm_should_quit;
+
+/*
+ * Info about socket and associated listener thread.
+ */
+struct sock_info {
+ char sock_path[PATH_MAX];
+ int socket;
+ pthread_t ust_listener; /* listener thread */
+ int root_handle;
+};
/* Socket from app (connect) to session daemon (listen) for communication */
-static char global_apps_sock_path[PATH_MAX] = DEFAULT_GLOBAL_APPS_UNIX_SOCK;
-static pthread_t global_ust_listener;
+struct sock_info global_apps = {
+ .sock_path = DEFAULT_GLOBAL_APPS_UNIX_SOCK,
+ .socket = -1,
+ .root_handle = -1,
+};
/* TODO: allow global_apps_sock_path override */
-static char local_apps_sock_path[PATH_MAX];
-static pthread_t local_ust_listener;
+struct sock_info local_apps = {
+ .socket = -1,
+ .root_handle = -1,
+};
static
int setup_local_apps_socket(void)
home_dir = (const char *) getenv("HOME");
if (!home_dir)
return -ENOENT;
- snprintf(local_apps_sock_path, PATH_MAX,
+ snprintf(local_apps.sock_path, PATH_MAX,
DEFAULT_HOME_APPS_UNIX_SOCK, home_dir);
return 0;
}
return ret;
}
+static
+int send_reply(int sock, struct lttcomm_ust_reply *lur)
+{
+ ssize_t len;
+
+ len = lttcomm_send_unix_sock(sock, lur, sizeof(*lur));
+ switch (len) {
+ case sizeof(*lur):
+ DBG("message successfully sent");
+ return 0;
+ case -1:
+ if (errno == ECONNRESET) {
+ printf("remote end closed connection\n");
+ return 0;
+ }
+ return -1;
+ default:
+ printf("incorrect message size: %zd\n", len);
+ return -1;
+ }
+}
static
int handle_message(int sock, struct lttcomm_ust_msg *lum)
{
- ssize_t len;
- int ret;
+ int ret = 0;
+ const struct objd_ops *ops;
+ struct lttcomm_ust_reply lur;
- switch (lum->cmd_type) {
- case UST_CREATE_SESSION:
- {
- struct lttcomm_ust_reply lur;
+ pthread_mutex_lock(<tng_ust_comm_mutex);
- DBG("Handling create session message");
- memset(&lur, 0, sizeof(lur));
- lur.cmd_type = UST_CREATE_SESSION;
+ memset(&lur, 0, sizeof(lur));
- /* ... */
- ret = 0;
+ if (lttng_ust_comm_should_quit) {
+ ret = -EPERM;
+ goto end;
+ }
- if (!ret)
- lur.ret_code = LTTCOMM_OK;
+ ops = objd_ops(lum->handle);
+ if (!ops) {
+ ret = -ENOENT;
+ goto end;
+ }
+
+ switch (lum->cmd) {
+ case LTTNG_UST_RELEASE:
+ if (lum->handle == LTTNG_UST_ROOT_HANDLE)
+ ret = -EPERM;
else
- lur.ret_code = LTTCOMM_SESSION_FAIL;
- lur.ret_val = 42;
- len = lttcomm_send_unix_sock(sock, &lur, sizeof(lur));
- switch (len) {
- case sizeof(lur):
- printf("message successfully sent\n");
- break;
- case -1:
- if (errno == ECONNRESET) {
- printf("remote end closed connection\n");
- return 0;
- }
- return -1;
- default:
- printf("incorrect message size: %zd\n", len);
- return -1;
- }
+ ret = objd_unref(lum->handle);
break;
- }
default:
- ERR("Unimplemented command %d", (int) lum->cmd_type);
- return -1;
+ if (ops->cmd)
+ ret = ops->cmd(lum->handle, lum->cmd,
+ (unsigned long) &lum->u);
+ else
+ ret = -ENOSYS;
+ break;
}
- return 0;
+
+end:
+ lur.handle = lum->handle;
+ lur.cmd = lum->cmd;
+ lur.ret_val = ret;
+ if (ret >= 0) {
+ lur.ret_code = LTTCOMM_OK;
+ } else {
+ lur.ret_code = LTTCOMM_SESSION_FAIL;
+ }
+ ret = send_reply(sock, &lur);
+
+ pthread_mutex_unlock(<tng_ust_comm_mutex);
+ return ret;
}
static
-void *ust_listener_thread(void *arg)
+void cleanup_sock_info(struct sock_info *sock_info)
{
- const char *sock_path = (const char *) arg;
- int sock;
int ret;
+ if (sock_info->socket != -1) {
+ ret = close(sock_info->socket);
+ if (ret) {
+ ERR("Error closing local apps socket");
+ }
+ sock_info->socket = -1;
+ }
+ if (sock_info->root_handle != -1) {
+ ret = objd_unref(sock_info->root_handle);
+ if (ret) {
+ ERR("Error unref root handle");
+ }
+ sock_info->root_handle = -1;
+ }
+}
+
+/*
+ * This thread does not allocate any resource, except within
+ * handle_message, within mutex protection. This mutex protects against
+ * fork and exit.
+ * The other moment it allocates resources is at socket connexion, which
+ * is also protected by the mutex.
+ */
+static
+void *ust_listener_thread(void *arg)
+{
+ struct sock_info *sock_info = arg;
+ int sock, ret;
+
/* Restart trying to connect to the session daemon */
restart:
+ pthread_mutex_lock(<tng_ust_comm_mutex);
+
+ if (lttng_ust_comm_should_quit) {
+ pthread_mutex_unlock(<tng_ust_comm_mutex);
+ goto quit;
+ }
+
+ if (sock_info->socket != -1) {
+ ret = close(sock_info->socket);
+ if (ret) {
+ ERR("Error closing local apps socket");
+ }
+ sock_info->socket = -1;
+ }
/* Check for sessiond availability with pipe TODO */
/* Register */
- ret = lttcomm_connect_unix_sock(sock_path);
+ ret = lttcomm_connect_unix_sock(sock_info->sock_path);
if (ret < 0) {
ERR("Error connecting to global apps socket");
+ pthread_mutex_unlock(<tng_ust_comm_mutex);
+ sleep(5);
+ goto restart;
}
- sock = ret;
+
+ sock_info->socket = sock = ret;
+
+ /*
+ * Create only one root handle per listener thread for the whole
+ * process lifetime.
+ */
+ if (sock_info->root_handle == -1) {
+ ret = lttng_abi_create_root_handle();
+ if (ret) {
+ ERR("Error creating root handle");
+ pthread_mutex_unlock(<tng_ust_comm_mutex);
+ goto quit;
+ }
+ sock_info->root_handle = ret;
+ }
+
ret = register_app_to_sessiond(sock);
if (ret < 0) {
ERR("Error registering app to local apps socket");
+ pthread_mutex_unlock(<tng_ust_comm_mutex);
sleep(5);
goto restart;
}
+ pthread_mutex_unlock(<tng_ust_comm_mutex);
+
for (;;) {
ssize_t len;
struct lttcomm_ust_msg lum;
- /* Receive session handle */
len = lttcomm_recv_unix_sock(sock, &lum, sizeof(lum));
switch (len) {
case 0: /* orderly shutdown */
case sizeof(lum):
DBG("message received\n");
ret = handle_message(sock, &lum);
- if (ret) {
+ if (ret < 0) {
ERR("Error handling message\n");
}
continue;
}
end:
- ret = close(sock);
- if (ret) {
- ERR("Error closing local apps socket");
- }
goto restart; /* try to reconnect */
+quit:
return NULL;
}
init_usterr();
- /* Connect to the per-user (local) sessiond apps socket */
ret = setup_local_apps_socket();
if (ret) {
ERR("Error setting up to local apps socket");
}
#if 0
- ret = pthread_create(&global_ust_listener, NULL,
- ust_listener_thread, global_apps_sock_path);
+ ret = pthread_create(&global_apps.ust_listener, NULL,
+ ust_listener_thread, &global_apps);
#endif //0
- ret = pthread_create(&local_ust_listener, NULL,
- ust_listener_thread, local_apps_sock_path);
+ ret = pthread_create(&local_apps.ust_listener, NULL,
+ ust_listener_thread, &local_apps);
}
void __attribute__((destructor)) lttng_ust_comm_exit(void)
* A) we don't want to hang application teardown.
* B) the thread is not allocating any resource.
*/
- ret = pthread_cancel(global_ust_listener);
+
+ /*
+ * Require the communication thread to quit. Synchronize with
+ * mutexes to ensure it is not in a mutex critical section when
+ * pthread_cancel is later called.
+ */
+ pthread_mutex_lock(<tng_ust_comm_mutex);
+ lttng_ust_comm_should_quit = 1;
+ pthread_mutex_unlock(<tng_ust_comm_mutex);
+
+#if 0
+ ret = pthread_cancel(global_apps.ust_listener);
if (ret) {
ERR("Error cancelling global ust listener thread");
}
- ret = pthread_cancel(local_ust_listener);
+#endif //0
+
+ cleanup_sock_info(&global_apps);
+
+ ret = pthread_cancel(local_apps.ust_listener);
if (ret) {
ERR("Error cancelling local ust listener thread");
}
+
+ cleanup_sock_info(&local_apps);
+
lttng_ust_abi_exit();
+ ltt_events_exit();
}
projects / lttng-ust.git / blobdiff