X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=liblttng-ust%2Flttng-ust-comm.c;h=59b9a98f4d74647b3cab1871148eeb451104a926;hb=824a00a7baa26b73d590d7ddae8c3e71fd0c9a66;hp=1a1f7181df22c262c4e3bb5a4546cac97ee95793;hpb=dde70ea0d552734c58d9776bb74b73b6314b9168;p=lttng-ust.git

diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c
index 1a1f7181..59b9a98f 100644
--- a/liblttng-ust/lttng-ust-comm.c
+++ b/liblttng-ust/lttng-ust-comm.c
@@ -43,6 +43,7 @@
 #include <lttng/ust.h>
 #include <ust-comm.h>
 #include <usterr-signal-safe.h>
+#include <helper.h>
 #include "tracepoint-internal.h"
 #include "ltt-tracer-core.h"
 #include "compat.h"
@@ -78,6 +79,12 @@ static sem_t constructor_wait;
  */
 static int sem_count = { 2 };
 
+/*
+ * Counting nesting within lttng-ust. Used to ensure that calling fork()
+ * from liblttng-ust does not execute the pre/post fork handlers.
+ */
+static int __thread lttng_ust_nest_count;
+
 /*
  * Info about socket and associated listener thread.
  */
@@ -130,6 +137,15 @@ extern void ltt_ring_buffer_client_overwrite_exit(void);
 extern void ltt_ring_buffer_client_discard_exit(void);
 extern void ltt_ring_buffer_metadata_client_exit(void);
 
+/*
+ * Force a read (imply TLS fixup for dlopen) of TLS variables.
+ */
+static
+void lttng_fixup_nest_count_tls(void)
+{
+	asm volatile ("" : : "m" (lttng_ust_nest_count));
+}
+
 static
 int setup_local_apps(void)
 {
@@ -141,14 +157,16 @@ int setup_local_apps(void)
 	 * Disallow per-user tracing for setuid binaries.
 	 */
 	if (uid != geteuid()) {
-		local_apps.allowed = 0;
+		assert(local_apps.allowed == 0);
 		return 0;
-	} else {
-		local_apps.allowed = 1;
 	}
 	home_dir = (const char *) getenv("HOME");
-	if (!home_dir)
+	if (!home_dir) {
+		WARN("HOME environment variable not set. Disabling LTTng-UST per-user tracing.");
+		assert(local_apps.allowed == 0);
 		return -ENOENT;
+	}
+	local_apps.allowed = 1;
 	snprintf(local_apps.sock_path, PATH_MAX,
 		 DEFAULT_HOME_APPS_UNIX_SOCK, home_dir);
 	snprintf(local_apps.wait_shm_path, PATH_MAX,
@@ -266,6 +284,74 @@ int handle_message(struct sock_info *sock_info,
 		else
 			ret = lttng_ust_objd_unref(lum->handle);
 		break;
+	case LTTNG_UST_FILTER:
+	{
+		/* Receive filter data */
+		struct lttng_ust_filter_bytecode *bytecode;
+
+		if (lum->u.filter.data_size > FILTER_BYTECODE_MAX_LEN) {
+			ERR("Filter data size is too large: %u bytes\n",
+				lum->u.filter.data_size);
+			ret = -EINVAL;
+			goto error;
+		}
+
+		if (lum->u.filter.reloc_offset > lum->u.filter.data_size) {
+			ERR("Filter reloc offset %u is not within data\n",
+				lum->u.filter.reloc_offset);
+			ret = -EINVAL;
+			goto error;
+		}
+
+		bytecode = zmalloc(sizeof(*bytecode) + lum->u.filter.data_size);
+		if (!bytecode) {
+			ret = -ENOMEM;
+			goto error;
+		}
+		len = ustcomm_recv_unix_sock(sock, bytecode->data,
+				lum->u.filter.data_size);
+		switch (len) {
+		case 0:	/* orderly shutdown */
+			ret = 0;
+			free(bytecode);
+			goto error;
+		case -1:
+			DBG("Receive failed from lttng-sessiond with errno %d", errno);
+			if (errno == ECONNRESET) {
+				ERR("%s remote end closed connection\n", sock_info->name);
+				ret = -EINVAL;
+				free(bytecode);
+				goto error;
+			}
+			ret = -EINVAL;
+			goto end;
+		default:
+			if (len == lum->u.filter.data_size) {
+				DBG("filter data received\n");
+				break;
+			} else {
+				ERR("incorrect filter data message size: %zd\n", len);
+				ret = -EINVAL;
+				free(bytecode);
+				goto end;
+			}
+		}
+		bytecode->len = lum->u.filter.data_size;
+		bytecode->reloc_offset = lum->u.filter.reloc_offset;
+		if (ops->cmd) {
+			ret = ops->cmd(lum->handle, lum->cmd,
+					(unsigned long) bytecode,
+					&args);
+			if (ret) {
+				free(bytecode);
+			}
+			/* don't free bytecode if everything went fine. */
+		} else {
+			ret = -ENOSYS;
+			free(bytecode);
+		}
+		break;
+	}
 	default:
 		if (ops->cmd)
 			ret = ops->cmd(lum->handle, lum->cmd,
@@ -481,7 +567,9 @@ int get_wait_shm(struct sock_info *sock_info, size_t mmap_size)
 	 * If the open failed because the file did not exist, try
 	 * creating it ourself.
 	 */
+	lttng_ust_nest_count++;
 	pid = fork();
+	lttng_ust_nest_count--;
 	if (pid > 0) {
 		int status;
 
@@ -530,9 +618,9 @@ int get_wait_shm(struct sock_info *sock_info, size_t mmap_size)
 			ret = ftruncate(wait_shm_fd, mmap_size);
 			if (ret) {
 				PERROR("ftruncate");
-				exit(EXIT_FAILURE);
+				_exit(EXIT_FAILURE);
 			}
-			exit(EXIT_SUCCESS);
+			_exit(EXIT_SUCCESS);
 		}
 		/*
 		 * For local shm, we need to have rw access to accept
@@ -544,13 +632,13 @@ int get_wait_shm(struct sock_info *sock_info, size_t mmap_size)
 		 */
 		if (!sock_info->global && errno != EACCES) {
 			ERR("Error opening shm %s", sock_info->wait_shm_path);
-			exit(EXIT_FAILURE);
+			_exit(EXIT_FAILURE);
 		}
 		/*
 		 * The shm exists, but we cannot open it RW. Report
 		 * success.
 		 */
-		exit(EXIT_SUCCESS);
+		_exit(EXIT_SUCCESS);
 	} else {
 		return -1;
 	}
@@ -664,7 +752,7 @@ error:
  * 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
+ * The other moment it allocates resources is at socket connection, which
  * is also protected by the mutex.
  */
 static
@@ -850,6 +938,7 @@ void __attribute__((constructor)) lttng_ust_init(void)
 {
 	struct timespec constructor_timeout;
 	sigset_t sig_all_blocked, orig_parent_mask;
+	pthread_attr_t thread_attr;
 	int timeout_mode;
 	int ret;
 
@@ -864,6 +953,8 @@ void __attribute__((constructor)) lttng_ust_init(void)
 	lttng_fixup_event_tls();
 	lttng_fixup_ringbuffer_tls();
 	lttng_fixup_vtid_tls();
+	lttng_fixup_nest_count_tls();
+	lttng_fixup_procname_tls();
 
 	/*
 	 * We want precise control over the order in which we construct
@@ -884,7 +975,7 @@ void __attribute__((constructor)) lttng_ust_init(void)
 
 	ret = setup_local_apps();
 	if (ret) {
-		ERR("Error setting up to local apps");
+		DBG("local apps setup returned %d", ret);
 	}
 
 	/* A new thread created by pthread_create inherits the signal mask
@@ -895,23 +986,41 @@ void __attribute__((constructor)) lttng_ust_init(void)
 	sigfillset(&sig_all_blocked);
 	ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_parent_mask);
 	if (ret) {
-		PERROR("pthread_sigmask: %s", strerror(ret));
+		ERR("pthread_sigmask: %s", strerror(ret));
 	}
 
-	ret = pthread_create(&global_apps.ust_listener, NULL,
-			ust_listener_thread, &global_apps);
+	ret = pthread_attr_init(&thread_attr);
+	if (ret) {
+		ERR("pthread_attr_init: %s", strerror(ret));
+	}
+	ret = pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED);
+	if (ret) {
+		ERR("pthread_attr_setdetachstate: %s", strerror(ret));
+	}
 
+	ret = pthread_create(&global_apps.ust_listener, &thread_attr,
+			ust_listener_thread, &global_apps);
+	if (ret) {
+		ERR("pthread_create global: %s", strerror(ret));
+	}
 	if (local_apps.allowed) {
-		ret = pthread_create(&local_apps.ust_listener, NULL,
+		ret = pthread_create(&local_apps.ust_listener, &thread_attr,
 				ust_listener_thread, &local_apps);
+		if (ret) {
+			ERR("pthread_create local: %s", strerror(ret));
+		}
 	} else {
 		handle_register_done(&local_apps);
 	}
+	ret = pthread_attr_destroy(&thread_attr);
+	if (ret) {
+		ERR("pthread_attr_destroy: %s", strerror(ret));
+	}
 
 	/* Restore original signal mask in parent */
 	ret = pthread_sigmask(SIG_SETMASK, &orig_parent_mask, NULL);
 	if (ret) {
-		PERROR("pthread_sigmask: %s", strerror(ret));
+		ERR("pthread_sigmask: %s", strerror(ret));
 	}
 
 	switch (timeout_mode) {
@@ -987,12 +1096,14 @@ void __attribute__((destructor)) lttng_ust_exit(void)
 	/* cancel threads */
 	ret = pthread_cancel(global_apps.ust_listener);
 	if (ret) {
-		ERR("Error cancelling global ust listener thread");
+		ERR("Error cancelling global ust listener thread: %s",
+			strerror(ret));
 	}
 	if (local_apps.allowed) {
 		ret = pthread_cancel(local_apps.ust_listener);
 		if (ret) {
-			ERR("Error cancelling local ust listener thread");
+			ERR("Error cancelling local ust listener thread: %s",
+				strerror(ret));
 		}
 	}
 	/*
@@ -1024,6 +1135,8 @@ void ust_before_fork(sigset_t *save_sigset)
 	sigset_t all_sigs;
 	int ret;
 
+	if (lttng_ust_nest_count)
+		return;
 	/* Disable signals */
 	sigfillset(&all_sigs);
 	ret = sigprocmask(SIG_BLOCK, &all_sigs, save_sigset);
@@ -1049,6 +1162,8 @@ static void ust_after_fork_common(sigset_t *restore_sigset)
 
 void ust_after_fork_parent(sigset_t *restore_sigset)
 {
+	if (lttng_ust_nest_count)
+		return;
 	DBG("process %d", getpid());
 	rcu_bp_after_fork_parent();
 	/* Release mutexes and reenable signals */
@@ -1066,6 +1181,8 @@ void ust_after_fork_parent(sigset_t *restore_sigset)
  */
 void ust_after_fork_child(sigset_t *restore_sigset)
 {
+	if (lttng_ust_nest_count)
+		return;
 	DBG("process %d", getpid());
 	/* Release urcu mutexes */
 	rcu_bp_after_fork_child();