From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Fri, 2 Mar 2012 17:57:38 +0000 (-0500)
Subject: Fix: large audit of close() use in sessiond main.c
X-Git-Tag: v2.0.0-rc2~12
X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=76d7553fcee76da7c103c3b51a6b01f46cd784c8

Fix: large audit of close() use in sessiond main.c

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/src/bin/lttng-sessiond/main.c b/src/bin/lttng-sessiond/main.c
index efe2143dd..17ef7f71c 100644
--- a/src/bin/lttng-sessiond/main.c
+++ b/src/bin/lttng-sessiond/main.c
@@ -125,19 +125,19 @@ static char wait_shm_path[PATH_MAX];
 static int client_sock = -1;
 static int apps_sock = -1;
 static int kernel_tracer_fd = -1;
-static int kernel_poll_pipe[2];
+static int kernel_poll_pipe[2] = { -1, -1 };
 
 /*
  * Quit pipe for all threads. This permits a single cancellation point
  * for all threads when receiving an event on the pipe.
  */
-static int thread_quit_pipe[2];
+static int thread_quit_pipe[2] = { -1, -1 };
 
 /*
  * This pipe is used to inform the thread managing application communication
  * that a command is queued and ready to be processed.
  */
-static int apps_cmd_pipe[2];
+static int apps_cmd_pipe[2] = { -1, -1 };
 
 /* Pthread, Mutexes and Semaphores */
 static pthread_t apps_thread;
@@ -299,7 +299,7 @@ static int init_thread_quit_pipe(void)
 
 	ret = pipe2(thread_quit_pipe, O_CLOEXEC);
 	if (ret < 0) {
-		perror("thread quit pipe");
+		PERROR("thread quit pipe");
 		goto error;
 	}
 
@@ -378,7 +378,7 @@ static void stop_threads(void)
  */
 static void cleanup(void)
 {
-	int ret;
+	int ret, i;
 	char *cmd;
 	struct ltt_session *sess, *stmp;
 
@@ -420,14 +420,43 @@ static void cleanup(void)
 	if (is_root && !opt_no_kernel) {
 		DBG2("Closing kernel fd");
 		if (kernel_tracer_fd >= 0) {
-			close(kernel_tracer_fd);
+			ret = close(kernel_tracer_fd);
+			if (ret) {
+				PERROR("close");
+			}
 		}
 		DBG("Unloading kernel modules");
 		modprobe_remove_lttng_all();
 	}
 
-	close(thread_quit_pipe[0]);
-	close(thread_quit_pipe[1]);
+	/*
+	 * Closing all pipes used for communication between threads.
+	 */
+	for (i = 0; i < 2; i++) {
+		if (kernel_poll_pipe[i] >= 0) {
+			ret = close(kernel_poll_pipe[i]);
+			if (ret) {
+				PERROR("close");
+			}
+			
+		}
+	}
+	for (i = 0; i < 2; i++) {
+		if (thread_quit_pipe[i] >= 0) {
+			ret = close(thread_quit_pipe[i]);
+			if (ret) {
+				PERROR("close");
+			}
+		}
+	}
+	for (i = 0; i < 2; i++) {
+		if (apps_cmd_pipe[i] >= 0) {
+			ret = close(apps_cmd_pipe[i]);
+			if (ret) {
+				PERROR("close");
+			}
+		}
+	}
 
 	/* <fun> */
 	DBG("%c[%d;%dm*** assert failed :-) *** ==> %c[%dm%c[%d;%dm"
@@ -491,7 +520,7 @@ static int send_kconsumer_channel_streams(struct consumer_data *consumer_data,
 	DBG("Sending channel %d to consumer", lkm.u.channel.channel_key);
 	ret = lttcomm_send_unix_sock(sock, &lkm, sizeof(lkm));
 	if (ret < 0) {
-		perror("send consumer channel");
+		PERROR("send consumer channel");
 		goto error;
 	}
 
@@ -513,12 +542,12 @@ static int send_kconsumer_channel_streams(struct consumer_data *consumer_data,
 		DBG("Sending stream %d to consumer", lkm.u.stream.stream_key);
 		ret = lttcomm_send_unix_sock(sock, &lkm, sizeof(lkm));
 		if (ret < 0) {
-			perror("send consumer stream");
+			PERROR("send consumer stream");
 			goto error;
 		}
 		ret = lttcomm_send_fds_unix_sock(sock, &stream->fd, 1);
 		if (ret < 0) {
-			perror("send consumer stream ancillary data");
+			PERROR("send consumer stream ancillary data");
 			goto error;
 		}
 	}
@@ -558,7 +587,7 @@ static int send_kconsumer_session_streams(struct consumer_data *consumer_data,
 		DBG("Sending metadata channel %d to consumer", lkm.u.stream.stream_key);
 		ret = lttcomm_send_unix_sock(sock, &lkm, sizeof(lkm));
 		if (ret < 0) {
-			perror("send consumer channel");
+			PERROR("send consumer channel");
 			goto error;
 		}
 
@@ -576,12 +605,12 @@ static int send_kconsumer_session_streams(struct consumer_data *consumer_data,
 		DBG("Sending metadata stream %d to consumer", lkm.u.stream.stream_key);
 		ret = lttcomm_send_unix_sock(sock, &lkm, sizeof(lkm));
 		if (ret < 0) {
-			perror("send consumer stream");
+			PERROR("send consumer stream");
 			goto error;
 		}
 		ret = lttcomm_send_fds_unix_sock(sock, &session->metadata_stream_fd, 1);
 		if (ret < 0) {
-			perror("send consumer stream");
+			PERROR("send consumer stream");
 			goto error;
 		}
 	}
@@ -642,7 +671,7 @@ static int setup_lttng_msg(struct command_ctx *cmd_ctx, size_t size)
 
 	cmd_ctx->llm = zmalloc(sizeof(struct lttcomm_lttng_msg) + buf_size);
 	if (cmd_ctx->llm == NULL) {
-		perror("zmalloc");
+		PERROR("zmalloc");
 		ret = -ENOMEM;
 		goto error;
 	}
@@ -802,7 +831,7 @@ static void *thread_manage_kernel(void *data)
 
 	ret = create_thread_poll_set(&events, 2);
 	if (ret < 0) {
-		goto error;
+		goto error_poll_create;
 	}
 
 	ret = lttng_poll_add(&events, kernel_poll_pipe[0], LPOLLIN);
@@ -887,12 +916,9 @@ static void *thread_manage_kernel(void *data)
 	}
 
 error:
-	DBG("Kernel thread dying");
-	close(kernel_poll_pipe[0]);
-	close(kernel_poll_pipe[1]);
-
 	lttng_poll_clean(&events);
-
+error_poll_create:
+	DBG("Kernel thread dying");
 	return NULL;
 }
 
@@ -901,7 +927,7 @@ error:
  */
 static void *thread_manage_consumer(void *data)
 {
-	int sock = 0, i, ret, pollfd;
+	int sock = -1, i, ret, pollfd;
 	uint32_t revents, nb_fd;
 	enum lttcomm_return_code code;
 	struct lttng_poll_event events;
@@ -911,7 +937,7 @@ static void *thread_manage_consumer(void *data)
 
 	ret = lttcomm_listen_unix_sock(consumer_data->err_sock);
 	if (ret < 0) {
-		goto error;
+		goto error_listen;
 	}
 
 	/*
@@ -920,7 +946,7 @@ static void *thread_manage_consumer(void *data)
 	 */
 	ret = create_thread_poll_set(&events, 2);
 	if (ret < 0) {
-		goto error;
+		goto error_poll;
 	}
 
 	ret = lttng_poll_add(&events, consumer_data->err_sock, LPOLLIN | LPOLLRDHUP);
@@ -1052,16 +1078,33 @@ restart_poll:
 	ERR("consumer return code : %s", lttcomm_get_readable_code(-code));
 
 error:
-	DBG("consumer thread dying");
-	close(consumer_data->err_sock);
-	close(consumer_data->cmd_sock);
-	close(sock);
+	if (consumer_data->err_sock >= 0) {
+		ret = close(consumer_data->err_sock);
+		if (ret) {
+			PERROR("close");
+		}
+	}
+	if (consumer_data->cmd_sock >= 0) {
+		ret = close(consumer_data->cmd_sock);
+		if (ret) {
+			PERROR("close");
+		}
+	}
+	if (sock >= 0) {
+		ret = close(sock);
+		if (ret) {
+			PERROR("close");
+		}
+	}
 
 	unlink(consumer_data->err_unix_sock_path);
 	unlink(consumer_data->cmd_unix_sock_path);
 	consumer_data->pid = 0;
 
 	lttng_poll_clean(&events);
+error_poll:
+error_listen:
+	DBG("consumer thread cleanup completed");
 
 	return NULL;
 }
@@ -1083,7 +1126,7 @@ static void *thread_manage_apps(void *data)
 
 	ret = create_thread_poll_set(&events, 2);
 	if (ret < 0) {
-		goto error;
+		goto error_poll_create;
 	}
 
 	ret = lttng_poll_add(&events, apps_cmd_pipe[0], LPOLLIN | LPOLLRDHUP);
@@ -1132,7 +1175,7 @@ static void *thread_manage_apps(void *data)
 					/* Empty pipe */
 					ret = read(apps_cmd_pipe[0], &ust_cmd, sizeof(ust_cmd));
 					if (ret < 0 || ret < sizeof(ust_cmd)) {
-						perror("read apps cmd pipe");
+						PERROR("read apps cmd pipe");
 						goto error;
 					}
 
@@ -1203,12 +1246,9 @@ static void *thread_manage_apps(void *data)
 	}
 
 error:
-	DBG("Application communication apps dying");
-	close(apps_cmd_pipe[0]);
-	close(apps_cmd_pipe[1]);
-
 	lttng_poll_clean(&events);
-
+error_poll_create:
+	DBG("Application communication apps thread cleanup complete");
 	rcu_thread_offline();
 	rcu_unregister_thread();
 	return NULL;
@@ -1255,7 +1295,7 @@ static void *thread_dispatch_ust_registration(void *data)
 			ret = write(apps_cmd_pipe[1], ust_cmd,
 					sizeof(struct ust_command));
 			if (ret < 0) {
-				perror("write apps cmd pipe");
+				PERROR("write apps cmd pipe");
 				if (errno == EBADF) {
 					/*
 					 * We can't inform the application thread to process
@@ -1296,7 +1336,7 @@ static void *thread_registration_apps(void *data)
 
 	ret = lttcomm_listen_unix_sock(apps_sock);
 	if (ret < 0) {
-		goto error;
+		goto error_listen;
 	}
 
 	/*
@@ -1305,13 +1345,13 @@ static void *thread_registration_apps(void *data)
 	 */
 	ret = create_thread_poll_set(&events, 2);
 	if (ret < 0) {
-		goto error;
+		goto error_create_poll;
 	}
 
 	/* Add the application registration socket */
 	ret = lttng_poll_add(&events, apps_sock, LPOLLIN | LPOLLRDHUP);
 	if (ret < 0) {
-		goto error;
+		goto error_poll_add;
 	}
 
 	/* Notify all applications to register */
@@ -1365,7 +1405,7 @@ static void *thread_registration_apps(void *data)
 					/* Create UST registration command for enqueuing */
 					ust_cmd = zmalloc(sizeof(struct ust_command));
 					if (ust_cmd == NULL) {
-						perror("ust command zmalloc");
+						PERROR("ust command zmalloc");
 						goto error;
 					}
 
@@ -1377,12 +1417,16 @@ static void *thread_registration_apps(void *data)
 							sizeof(struct ust_register_msg));
 					if (ret < 0 || ret < sizeof(struct ust_register_msg)) {
 						if (ret < 0) {
-							perror("lttcomm_recv_unix_sock register apps");
+							PERROR("lttcomm_recv_unix_sock register apps");
 						} else {
 							ERR("Wrong size received on apps register");
 						}
 						free(ust_cmd);
-						close(sock);
+						ret = close(sock);
+						if (ret) {
+							PERROR("close");
+						}
+						sock = -1;
 						continue;
 					}
 
@@ -1412,20 +1456,28 @@ static void *thread_registration_apps(void *data)
 	}
 
 error:
-	DBG("UST Registration thread dying");
-
 	/* Notify that the registration thread is gone */
 	notify_ust_apps(0);
 
 	if (apps_sock >= 0) {
-		close(apps_sock);
+		ret = close(apps_sock);
+		if (ret) {
+			PERROR("close");
+		}
 	}
 	if (clock >= 0) {
-		close(sock);
+		ret = close(sock);
+		if (ret) {
+			PERROR("close");
+		}
 	}
 	unlink(apps_unix_sock_path);
 
+error_poll_add:
 	lttng_poll_clean(&events);
+error_listen:
+error_create_poll:
+	DBG("UST Registration thread cleanup complete");
 
 	return NULL;
 }
@@ -1665,17 +1717,17 @@ static pid_t spawn_consumerd(struct consumer_data *consumer_data)
 			break;
 		}
 		default:
-			perror("unknown consumer type");
+			PERROR("unknown consumer type");
 			exit(EXIT_FAILURE);
 		}
 		if (errno != 0) {
-			perror("kernel start consumer exec");
+			PERROR("kernel start consumer exec");
 		}
 		exit(EXIT_FAILURE);
 	} else if (pid > 0) {
 		ret = pid;
 	} else {
-		perror("start consumer fork");
+		PERROR("start consumer fork");
 		ret = -errno;
 	}
 error:
@@ -1766,12 +1818,18 @@ static int init_kernel_tracer(void)
 
 error_version:
 	modprobe_remove_lttng_control();
-	close(kernel_tracer_fd);
-	kernel_tracer_fd = 0;
+	ret = close(kernel_tracer_fd);
+	if (ret) {
+		PERROR("close");
+	}
+	kernel_tracer_fd = -1;
 	return LTTCOMM_KERN_VERSION;
 
 error_modules:
-	close(kernel_tracer_fd);
+	ret = close(kernel_tracer_fd);
+	if (ret) {
+		PERROR("close");
+	}
 
 error_open:
 	modprobe_remove_lttng_control();
@@ -2948,7 +3006,7 @@ static int cmd_destroy_session(struct ltt_session *session, char *name)
 	 */
 	ret = notify_thread_pipe(kernel_poll_pipe[1]);
 	if (ret < 0) {
-		perror("write kernel poll pipe");
+		PERROR("write kernel poll pipe");
 	}
 
 	ret = session_destroy(session);
@@ -3685,14 +3743,14 @@ static void *thread_manage_clients(void *data)
 		/* Allocate context command to process the client request */
 		cmd_ctx = zmalloc(sizeof(struct command_ctx));
 		if (cmd_ctx == NULL) {
-			perror("zmalloc cmd_ctx");
+			PERROR("zmalloc cmd_ctx");
 			goto error;
 		}
 
 		/* Allocate data buffer for reception */
 		cmd_ctx->lsm = zmalloc(sizeof(struct lttcomm_session_msg));
 		if (cmd_ctx->lsm == NULL) {
-			perror("zmalloc cmd_ctx->lsm");
+			PERROR("zmalloc cmd_ctx->lsm");
 			goto error;
 		}
 
@@ -3709,7 +3767,11 @@ static void *thread_manage_clients(void *data)
 				sizeof(struct lttcomm_session_msg), &cmd_ctx->creds);
 		if (ret <= 0) {
 			DBG("Nothing recv() from client... continuing");
-			close(sock);
+			ret = close(sock);
+			if (ret) {
+				PERROR("close");
+			}
+			sock = -1;
 			free(cmd_ctx);
 			continue;
 		}
@@ -3745,7 +3807,11 @@ static void *thread_manage_clients(void *data)
 		}
 
 		/* End of transmission */
-		close(sock);
+		ret = close(sock);
+		if (ret) {
+			PERROR("close");
+		}
+		sock = -1;
 
 		clean_command_ctx(&cmd_ctx);
 	}
@@ -3753,11 +3819,17 @@ static void *thread_manage_clients(void *data)
 error:
 	DBG("Client thread dying");
 	unlink(client_unix_sock_path);
-	if (sock >= 0) {
-		close(client_sock);
+	if (client_sock >= 0) {
+		ret = close(client_sock);
+		if (ret) {
+			PERROR("close");
+		}
 	}
 	if (sock >= 0) {
-		close(sock);
+		ret = close(sock);
+		if (ret) {
+			PERROR("close");
+		}
 	}
 
 	lttng_poll_clean(&events);
@@ -3942,7 +4014,7 @@ static int init_daemon_socket(void)
 	ret = chmod(client_unix_sock_path, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
 	if (ret < 0) {
 		ERR("Set file permissions failed: %s", client_unix_sock_path);
-		perror("chmod");
+		PERROR("chmod");
 		goto end;
 	}
 
@@ -3959,7 +4031,7 @@ static int init_daemon_socket(void)
 			S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
 	if (ret < 0) {
 		ERR("Set file permissions failed: %s", apps_unix_sock_path);
-		perror("chmod");
+		PERROR("chmod");
 		goto end;
 	}
 
@@ -4004,42 +4076,42 @@ static int set_permissions(char *rundir)
 	ret = chown(rundir, 0, gid);
 	if (ret < 0) {
 		ERR("Unable to set group on %s", rundir);
-		perror("chown");
+		PERROR("chown");
 	}
 
 	/* Ensure tracing group can search the run dir */
 	ret = chmod(rundir, S_IRWXU | S_IXGRP | S_IXOTH);
 	if (ret < 0) {
 		ERR("Unable to set permissions on %s", rundir);
-		perror("chmod");
+		PERROR("chmod");
 	}
 
 	/* lttng client socket path */
 	ret = chown(client_unix_sock_path, 0, gid);
 	if (ret < 0) {
 		ERR("Unable to set group on %s", client_unix_sock_path);
-		perror("chown");
+		PERROR("chown");
 	}
 
 	/* kconsumer error socket path */
 	ret = chown(kconsumer_data.err_unix_sock_path, 0, gid);
 	if (ret < 0) {
 		ERR("Unable to set group on %s", kconsumer_data.err_unix_sock_path);
-		perror("chown");
+		PERROR("chown");
 	}
 
 	/* 64-bit ustconsumer error socket path */
 	ret = chown(ustconsumer64_data.err_unix_sock_path, 0, gid);
 	if (ret < 0) {
 		ERR("Unable to set group on %s", ustconsumer64_data.err_unix_sock_path);
-		perror("chown");
+		PERROR("chown");
 	}
 
 	/* 32-bit ustconsumer compat32 error socket path */
 	ret = chown(ustconsumer32_data.err_unix_sock_path, 0, gid);
 	if (ret < 0) {
 		ERR("Unable to set group on %s", ustconsumer32_data.err_unix_sock_path);
-		perror("chown");
+		PERROR("chown");
 	}
 
 	DBG("All permissions are set");
@@ -4050,6 +4122,7 @@ end:
 
 /*
  * Create the pipe used to wake up the kernel thread.
+ * Closed in cleanup().
  */
 static int create_kernel_poll_pipe(void)
 {
@@ -4058,6 +4131,7 @@ static int create_kernel_poll_pipe(void)
 
 /*
  * Create the application command pipe to wake thread_manage_apps.
+ * Closed in cleanup().
  */
 static int create_apps_cmd_pipe(void)
 {
@@ -4182,7 +4256,7 @@ static int set_signal_handler(void)
 	sigset_t sigset;
 
 	if ((ret = sigemptyset(&sigset)) < 0) {
-		perror("sigemptyset");
+		PERROR("sigemptyset");
 		return ret;
 	}
 
@@ -4190,17 +4264,17 @@ static int set_signal_handler(void)
 	sa.sa_mask = sigset;
 	sa.sa_flags = 0;
 	if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) {
-		perror("sigaction");
+		PERROR("sigaction");
 		return ret;
 	}
 
 	if ((ret = sigaction(SIGINT, &sa, NULL)) < 0) {
-		perror("sigaction");
+		PERROR("sigaction");
 		return ret;
 	}
 
 	if ((ret = sigaction(SIGPIPE, &sa, NULL)) < 0) {
-		perror("sigaction");
+		PERROR("sigaction");
 		return ret;
 	}
 
@@ -4224,7 +4298,7 @@ static void set_ulimit(void)
 
 	ret = setrlimit(RLIMIT_NOFILE, &lim);
 	if (ret < 0) {
-		perror("failed to set open files limit");
+		PERROR("failed to set open files limit");
 	}
 }
 
@@ -4258,7 +4332,7 @@ int main(int argc, char **argv)
 	if (opt_daemon) {
 		ret = daemon(0, 0);
 		if (ret < 0) {
-			perror("daemon");
+			PERROR("daemon");
 			goto error;
 		}
 	}
@@ -4462,7 +4536,7 @@ int main(int argc, char **argv)
 	ret = pthread_create(&client_thread, NULL,
 			thread_manage_clients, (void *) NULL);
 	if (ret != 0) {
-		perror("pthread_create clients");
+		PERROR("pthread_create clients");
 		goto exit_client;
 	}
 
@@ -4470,7 +4544,7 @@ int main(int argc, char **argv)
 	ret = pthread_create(&dispatch_thread, NULL,
 			thread_dispatch_ust_registration, (void *) NULL);
 	if (ret != 0) {
-		perror("pthread_create dispatch");
+		PERROR("pthread_create dispatch");
 		goto exit_dispatch;
 	}
 
@@ -4478,7 +4552,7 @@ int main(int argc, char **argv)
 	ret = pthread_create(&reg_apps_thread, NULL,
 			thread_registration_apps, (void *) NULL);
 	if (ret != 0) {
-		perror("pthread_create registration");
+		PERROR("pthread_create registration");
 		goto exit_reg_apps;
 	}
 
@@ -4486,7 +4560,7 @@ int main(int argc, char **argv)
 	ret = pthread_create(&apps_thread, NULL,
 			thread_manage_apps, (void *) NULL);
 	if (ret != 0) {
-		perror("pthread_create apps");
+		PERROR("pthread_create apps");
 		goto exit_apps;
 	}
 
@@ -4494,47 +4568,47 @@ int main(int argc, char **argv)
 	ret = pthread_create(&kernel_thread, NULL,
 			thread_manage_kernel, (void *) NULL);
 	if (ret != 0) {
-		perror("pthread_create kernel");
+		PERROR("pthread_create kernel");
 		goto exit_kernel;
 	}
 
 	ret = pthread_join(kernel_thread, &status);
 	if (ret != 0) {
-		perror("pthread_join");
+		PERROR("pthread_join");
 		goto error;	/* join error, exit without cleanup */
 	}
 
 exit_kernel:
 	ret = pthread_join(apps_thread, &status);
 	if (ret != 0) {
-		perror("pthread_join");
+		PERROR("pthread_join");
 		goto error;	/* join error, exit without cleanup */
 	}
 
 exit_apps:
 	ret = pthread_join(reg_apps_thread, &status);
 	if (ret != 0) {
-		perror("pthread_join");
+		PERROR("pthread_join");
 		goto error;	/* join error, exit without cleanup */
 	}
 
 exit_reg_apps:
 	ret = pthread_join(dispatch_thread, &status);
 	if (ret != 0) {
-		perror("pthread_join");
+		PERROR("pthread_join");
 		goto error;	/* join error, exit without cleanup */
 	}
 
 exit_dispatch:
 	ret = pthread_join(client_thread, &status);
 	if (ret != 0) {
-		perror("pthread_join");
+		PERROR("pthread_join");
 		goto error;	/* join error, exit without cleanup */
 	}
 
 	ret = join_consumer_thread(&kconsumer_data);
 	if (ret != 0) {
-		perror("join_consumer");
+		PERROR("join_consumer");
 		goto error;	/* join error, exit without cleanup */
 	}
 
diff --git a/src/common/compat/poll.h b/src/common/compat/poll.h
index 1580a4fb2..7af2ef050 100644
--- a/src/common/compat/poll.h
+++ b/src/common/compat/poll.h
@@ -50,6 +50,7 @@ static inline void __lttng_poll_free(void *events)
  */
 #ifdef HAVE_EPOLL
 #include <sys/epoll.h>
+#include <stdio.h>
 
 /* See man epoll(7) for this define path */
 #define COMPAT_EPOLL_PROC_PATH "/proc/sys/fs/epoll/max_user_watches"
@@ -146,8 +147,13 @@ static inline void lttng_poll_reset(struct lttng_poll_event *events)
  */
 static inline void lttng_poll_clean(struct lttng_poll_event *events)
 {
+	int ret;
+
 	if (events) {
-		close(events->epfd);
+		ret = close(events->epfd);
+		if (ret) {
+			perror("close");
+		}
 		__lttng_poll_free((void *) events->events);
 	}
 }
diff --git a/src/common/error.h b/src/common/error.h
index 81c20223d..822dccfed 100644
--- a/src/common/error.h
+++ b/src/common/error.h
@@ -75,7 +75,8 @@ extern int opt_verbose;
 		" [in %s() at " __FILE__ ":" XSTR(__LINE__) "]\n", ## args, __func__)
 
 #define _PERROR(fmt, args...) \
-	__lttng_print(PRINT_ERR, "perror " fmt "\n", ## args)
+	__lttng_print(PRINT_ERR, "PERROR: " fmt \
+		" [in %s() at " __FILE__ ":" XSTR(__LINE__) "]\n", ## args, __func__)
 
 #define PERROR(call, args...) \
     do { \