X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=liblttng-ust%2Flttng-ust-comm.c;h=b61833155425988d261e9e584247e3b76ebf9c90;hb=2eb235ecd28828cef90ff371a96cd532e92ba9f6;hp=eec049b31fb2a09de4add833adac706e2e4168ce;hpb=553bbf7f38652084ed7966c7817b8ccb372b14e1;p=lttng-ust.git

diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c
index eec049b3..b6183315 100644
--- a/liblttng-ust/lttng-ust-comm.c
+++ b/liblttng-ust/lttng-ust-comm.c
@@ -27,6 +27,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+#include <dlfcn.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <errno.h>
@@ -59,6 +60,9 @@
 #include "../libringbuffer/getcpu.h"
 #include "getenv.h"
 
+/* Concatenate lttng ust shared library name with its major version number. */
+#define LTTNG_UST_LIB_SO_NAME "liblttng-ust.so." LTTNG_UST_LIBRARY_VERSION_MAJOR
+
 /*
  * Has lttng ust comm constructor been called ?
  */
@@ -86,7 +90,7 @@ static int initialized;
 static pthread_mutex_t ust_mutex = PTHREAD_MUTEX_INITIALIZER;
 
 /* Allow nesting the ust_mutex within the same thread. */
-static DEFINE_URCU_TLS_IE(int, ust_mutex_nest);
+static DEFINE_URCU_TLS(int, ust_mutex_nest);
 
 /*
  * ust_exit_mutex protects thread_active variable wrt thread exit. It
@@ -1261,7 +1265,18 @@ char *get_map_shm(struct sock_info *sock_info)
 		lttng_ust_unlock_fd_tracker();
 		goto error;
 	}
-	lttng_ust_add_fd_to_tracker(wait_shm_fd);
+
+	ret = lttng_ust_add_fd_to_tracker(wait_shm_fd);
+	if (ret < 0) {
+		ret = close(wait_shm_fd);
+		if (!ret) {
+			PERROR("Error closing fd");
+		}
+		lttng_ust_unlock_fd_tracker();
+		goto error;
+	}
+
+	wait_shm_fd = ret;
 	lttng_ust_unlock_fd_tracker();
 
 	wait_shm_mmap = mmap(NULL, page_size, PROT_READ,
@@ -1353,7 +1368,7 @@ static
 void *ust_listener_thread(void *arg)
 {
 	struct sock_info *sock_info = arg;
-	int sock, ret, prev_connect_failed = 0, has_waited = 0;
+	int sock, ret, prev_connect_failed = 0, has_waited = 0, fd;
 	long timeout;
 
 	lttng_ust_fixup_tls();
@@ -1385,6 +1400,10 @@ restart:
 		prev_connect_failed = 0;
 	}
 
+	if (ust_lock()) {
+		goto quit;
+	}
+
 	if (sock_info->socket != -1) {
 		/* FD tracker is updated by ustcomm_close_unix_sock() */
 		ret = ustcomm_close_unix_sock(sock_info->socket);
@@ -1404,9 +1423,6 @@ restart:
 		sock_info->notify_socket = -1;
 	}
 
-	if (ust_lock()) {
-		goto quit;
-	}
 
 	/*
 	 * Register. We need to perform both connect and sending
@@ -1433,9 +1449,21 @@ restart:
 		ust_unlock();
 		goto restart;
 	}
-	lttng_ust_add_fd_to_tracker(ret);
-	lttng_ust_unlock_fd_tracker();
+	fd = ret;
+	ret = lttng_ust_add_fd_to_tracker(fd);
+	if (ret < 0) {
+		ret = close(fd);
+		if (ret) {
+			PERROR("close on sock_info->socket");
+		}
+		ret = -1;
+		lttng_ust_unlock_fd_tracker();
+		ust_unlock();
+		goto quit;
+	}
+
 	sock_info->socket = ret;
+	lttng_ust_unlock_fd_tracker();
 
 	ust_unlock();
 	/*
@@ -1504,9 +1532,22 @@ restart:
 		ust_unlock();
 		goto restart;
 	}
-	lttng_ust_add_fd_to_tracker(ret);
-	lttng_ust_unlock_fd_tracker();
+
+	fd = ret;
+	ret = lttng_ust_add_fd_to_tracker(fd);
+	if (ret < 0) {
+		ret = close(fd);
+		if (ret) {
+			PERROR("close on sock_info->notify_socket");
+		}
+		ret = -1;
+		lttng_ust_unlock_fd_tracker();
+		ust_unlock();
+		goto quit;
+	}
+
 	sock_info->notify_socket = ret;
+	lttng_ust_unlock_fd_tracker();
 
 	ust_unlock();
 	/*
@@ -1648,6 +1689,7 @@ void __attribute__((constructor)) lttng_ust_init(void)
 	pthread_attr_t thread_attr;
 	int timeout_mode;
 	int ret;
+	void *handle;
 
 	if (uatomic_xchg(&initialized, 1) == 1)
 		return;
@@ -1661,6 +1703,26 @@ void __attribute__((constructor)) lttng_ust_init(void)
 
 	lttng_ust_loaded = 1;
 
+	/*
+	 * We need to ensure that the liblttng-ust library is not unloaded to avoid
+	 * the unloading of code used by the ust_listener_threads as we can not
+	 * reliably know when they exited. To do that, manually load
+	 * liblttng-ust.so to increment the dynamic loader's internal refcount for
+	 * this library so it never becomes zero, thus never gets unloaded from the
+	 * address space of the process. Since we are already running in the
+	 * constructor of the LTTNG_UST_LIB_SO_NAME library, calling dlopen will
+	 * simply increment the refcount and no additionnal work is needed by the
+	 * dynamic loader as the shared library is already loaded in the address
+	 * space. As a safe guard, we use the RTLD_NODELETE flag to prevent
+	 * unloading of the UST library if its refcount becomes zero (which should
+	 * never happen). Do the return value check but discard the handle at the
+	 * end of the function as it's not needed.
+	 */
+	handle = dlopen(LTTNG_UST_LIB_SO_NAME, RTLD_LAZY | RTLD_NODELETE);
+	if (!handle) {
+		ERR("dlopen of liblttng-ust shared library (%s).", LTTNG_UST_LIB_SO_NAME);
+	}
+
 	/*
 	 * We want precise control over the order in which we construct
 	 * our sub-libraries vs starting to receive commands from
@@ -1949,7 +2011,9 @@ void ust_after_fork_child(sigset_t *restore_sigset)
 {
 	if (URCU_TLS(lttng_ust_nest_count))
 		return;
+	lttng_context_vpid_reset();
 	lttng_context_vtid_reset();
+	lttng_context_procname_reset();
 	DBG("process %d", getpid());
 	/* Release urcu mutexes */
 	rcu_bp_after_fork_child();