X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;ds=sidebyside;f=src%2Fbin%2Flttng-sessiond%2Fagent-thread.c;h=9ac975cbf1ea9539c4d81db352089b25d12af561;hb=d558f2363a2daf3e456a28a6089f7464837ed542;hp=6790a63c642bd78bb37484a6c6af0b1af39081c7;hpb=fefd409b002735b415c5f653cdb2587be454f145;p=lttng-tools.git

diff --git a/src/bin/lttng-sessiond/agent-thread.c b/src/bin/lttng-sessiond/agent-thread.c
index 6790a63c6..9ac975cbf 100644
--- a/src/bin/lttng-sessiond/agent-thread.c
+++ b/src/bin/lttng-sessiond/agent-thread.c
@@ -16,6 +16,7 @@
  */
 
 #define _GNU_SOURCE
+#define _LGPL_SOURCE
 #include <assert.h>
 
 #include <common/common.h>
@@ -60,10 +61,12 @@ static void update_agent_app(struct agent_app *app)
 		if (session->ust_session) {
 			struct agent *agt;
 
+			rcu_read_lock();
 			agt = trace_ust_find_agent(session->ust_session, app->domain);
 			if (agt) {
 				agent_update(agt, app->sock->fd);
 			}
+			rcu_read_unlock();
 		}
 		session_unlock(session);
 	}
@@ -87,13 +90,13 @@ static void destroy_agent_app(int sock)
 	rcu_read_lock();
 	app = agent_find_app_by_sock(sock);
 	assert(app);
-	rcu_read_unlock();
 
-	/* RCU read side lock is taken in this function call. */
+	/* RCU read side lock is assumed to be held by this function. */
 	agent_delete_app(app);
 
 	/* The application is freed in a RCU call but the socket is closed here. */
 	agent_destroy_app(app);
+	rcu_read_unlock();
 }
 
 /*
@@ -198,6 +201,7 @@ static int handle_registration(struct lttcomm_sock *reg_sock,
 {
 	int ret;
 	pid_t pid;
+	uint32_t major_version, minor_version;
 	ssize_t size;
 	enum lttng_domain_type domain;
 	struct agent_app *app;
@@ -214,11 +218,23 @@ static int handle_registration(struct lttcomm_sock *reg_sock,
 
 	size = new_sock->ops->recvmsg(new_sock, &msg, sizeof(msg), 0);
 	if (size < sizeof(msg)) {
-		ret = -errno;
+		ret = -EINVAL;
 		goto error_socket;
 	}
 	domain = be32toh(msg.domain);
 	pid = be32toh(msg.pid);
+	major_version = be32toh(msg.major_version);
+	minor_version = be32toh(msg.minor_version);
+
+	/* Test communication protocol version of the registring agent. */
+	if (major_version != AGENT_MAJOR_VERSION) {
+		ret = -EINVAL;
+		goto error_socket;
+	}
+	if (minor_version != AGENT_MINOR_VERSION) {
+		ret = -EINVAL;
+		goto error_socket;
+	}
 
 	DBG2("[agent-thread] New registration for pid %d domain %d on socket %d",
 			pid, domain, new_sock->fd);
@@ -291,12 +307,13 @@ void *agent_thread_manage_registration(void *data)
 	}
 
 	while (1) {
-		DBG3("[agent-thread] Manage agent polling on %d fds",
-				LTTNG_POLL_GETNB(&events));
+		DBG3("[agent-thread] Manage agent polling");
 
 		/* Inifinite blocking call, waiting for transmission */
 restart:
 		ret = lttng_poll_wait(&events, -1);
+		DBG3("[agent-thread] Manage agent return from poll on %d fds",
+				LTTNG_POLL_GETNB(&events));
 		if (ret < 0) {
 			/*
 			 * Restart interrupted system call.
@@ -314,6 +331,11 @@ restart:
 			revents = LTTNG_POLL_GETEV(&events, i);
 			pollfd = LTTNG_POLL_GETFD(&events, i);
 
+			if (!revents) {
+				/* No activity for this FD (poll implementation). */
+				continue;
+			}
+
 			/* Thread quit pipe has been closed. Killing thread. */
 			ret = sessiond_check_thread_quit_pipe(pollfd, revents);
 			if (ret) {