X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=ltt-sessiond%2Fmain.c;h=eb5d47f62bb6b9bab5e04c7f91524ce22c8c1b12;hp=5337d6df44781980c7cc77fd4211932fcf540de0;hb=1b6083d908666ac98359cd8fc1b32158196db18d;hpb=1d4b027abdef2dc52b41b05ec56c5046c5000c4c

diff --git a/ltt-sessiond/main.c b/ltt-sessiond/main.c
index 5337d6df4..eb5d47f62 100644
--- a/ltt-sessiond/main.c
+++ b/ltt-sessiond/main.c
@@ -390,22 +390,28 @@ static void *thread_manage_kconsumerd(void *data)
 		sem_post(&kconsumerd_sem);
 		DBG("Kconsumerd command socket ready");
 	} else {
-		DBG("[sessiond] Kconsumerd error when waiting for SOCK_READY : %s",
+		DBG("Kconsumerd error when waiting for SOCK_READY : %s",
 				lttcomm_get_readable_code(-code));
 		goto error;
 	}
 
-	/* Wait for any kconsumerd error */
-	ret = lttcomm_recv_unix_sock(sock, &code, sizeof(enum lttcomm_return_code));
-	if (ret <= 0) {
-		ERR("[sessiond] Kconsumerd closed the command socket");
-		goto error;
-	}
+	while (1) {
+		/* Wait for any kconsumerd error */
+		ret = lttcomm_recv_unix_sock(sock, &code, sizeof(enum lttcomm_return_code));
+		if (ret <= 0) {
+			ERR("Kconsumerd closed the command socket");
+			goto error;
+		}
 
-	ERR("Kconsumerd return code : %s", lttcomm_get_readable_code(-code));
+		ERR("Kconsumerd return code : %s", lttcomm_get_readable_code(-code));
+		if (code != KCONSUMERD_POLL_HUP) {
+			goto error;
+		}
+	}
 
 error:
 	kconsumerd_pid = 0;
+	DBG("Kconsumerd thread dying");
 	return NULL;
 }
 
@@ -477,12 +483,12 @@ error:
 }
 
 /*
- *  start_kconsumerd_thread
+ *  spawn_kconsumerd_thread
  *
  *  Start the thread_manage_kconsumerd. This must be done after a kconsumerd
  *  exec or it will fails.
  */
-static int start_kconsumerd_thread(void)
+static int spawn_kconsumerd_thread(void)
 {
 	int ret;
 
@@ -495,6 +501,7 @@ static int start_kconsumerd_thread(void)
 		goto error;
 	}
 
+	/* Wait for the kconsumerd thread to be ready */
 	sem_wait(&kconsumerd_sem);
 
 	return 0;
@@ -504,13 +511,17 @@ error:
 }
 
 /*
- *  kernel_start_consumer
+ *  spawn_kconsumerd
+ *
+ *  Fork and exec a kernel consumer daemon (kconsumerd).
  *
- *  Start a kernel consumer daemon (kconsumerd).
+ *  NOTE: It is very important to fork a kconsumerd BEFORE opening any kernel
+ *  file descriptor using the libkernelctl or kernel-ctl functions. So, a
+ *  kernel consumer MUST only be spawned before creating a kernel session.
  *
  *  Return pid if successful else -1.
  */
-pid_t kernel_start_consumer(void)
+static pid_t spawn_kconsumerd(void)
 {
 	int ret;
 	pid_t pid;
@@ -538,6 +549,49 @@ error:
 	return ret;
 }
 
+/*
+ *  start_kconsumerd
+ *
+ *  Spawn the kconsumerd daemon and session daemon thread.
+ */
+static int start_kconsumerd(void)
+{
+	int ret;
+
+	DBG("Spawning kconsumerd");
+
+	pthread_mutex_lock(&kconsumerd_pid_mutex);
+	if (kconsumerd_pid == 0) {
+		ret = spawn_kconsumerd();
+		if (ret < 0) {
+			ERR("Spawning kconsumerd failed");
+			ret = LTTCOMM_KERN_CONSUMER_FAIL;
+			pthread_mutex_unlock(&kconsumerd_pid_mutex);
+			goto error;
+		}
+
+		/* Setting up the global kconsumerd_pid */
+		kconsumerd_pid = ret;
+	}
+	pthread_mutex_unlock(&kconsumerd_pid_mutex);
+
+	DBG("Kconsumerd pid %d", ret);
+
+	DBG("Spawning kconsumerd thread");
+
+	ret = spawn_kconsumerd_thread();
+	if (ret < 0) {
+		ERR("Fatal error spawning kconsumerd thread");
+		ret = LTTCOMM_FATAL;
+		goto error;
+	}
+
+	return 0;
+
+error:
+	return ret;
+}
+
 /*
  *  send_kconsumerd_fds
  *
@@ -612,6 +666,7 @@ static int create_trace_dir(struct ltt_kernel_session *session)
 
 	/* Create all channel directories */
 	cds_list_for_each_entry(chan, &session->channel_list.head, list) {
+		DBG("Creating trace directory at %s", chan->pathname);
 		ret = mkdir(chan->pathname, S_IRWXU | S_IRWXG );
 		if (ret < 0) {
 			perror("mkdir trace path");
@@ -626,7 +681,6 @@ error:
 	return ret;
 }
 
-
 /*
  * 	process_client_msg
  *
@@ -695,26 +749,8 @@ static int process_client_msg(struct command_ctx *cmd_ctx)
 			goto setup_error;
 		}
 
-		DBG("Checking if kconsumerd is alive");
-		pthread_mutex_lock(&kconsumerd_pid_mutex);
-		if (kconsumerd_pid == 0) {
-			ret = kernel_start_consumer();
-			if (ret < 0) {
-				ERR("Kernel start kconsumerd failed");
-				ret = LTTCOMM_KERN_CONSUMER_FAIL;
-				pthread_mutex_unlock(&kconsumerd_pid_mutex);
-				goto error;
-			}
-
-			/* Setting up the global kconsumerd_pid */
-			kconsumerd_pid = ret;
-		}
-		pthread_mutex_unlock(&kconsumerd_pid_mutex);
-
-		ret = start_kconsumerd_thread();
+		ret = start_kconsumerd();
 		if (ret < 0) {
-			ERR("Fatal error : start_kconsumerd_thread()");
-			ret = LTTCOMM_FATAL;
 			goto error;
 		}
 
@@ -864,6 +900,11 @@ static int process_client_msg(struct command_ctx *cmd_ctx)
 			goto setup_error;
 		}
 
+		if (cmd_ctx->session->kernel_session == NULL) {
+			ret = LTTCOMM_KERN_NO_SESSION;
+			goto error;
+		}
+
 		DBG("Stop kernel tracing");
 
 		ret = kernel_stop_session(cmd_ctx->session->kernel_session);