X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=liblttng-ust%2Flttng-ust-comm.c;h=a464e88bfee2143e429273c646adabbf8aaa61bb;hb=6ddc916dfa930b6b9018ffd53a76faeb61b81ebd;hp=0765c9b538a6a9370570647fea6780fe49070705;hpb=50be2fc41b02ee04860b5199d0ce2d346b1ea7c2;p=lttng-ust.git

diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c
index 0765c9b5..a464e88b 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)
 {
@@ -236,6 +252,7 @@ int handle_message(struct sock_info *sock_info,
 	struct ustcomm_ust_reply lur;
 	int shm_fd, wait_fd;
 	union ust_args args;
+	ssize_t len;
 
 	ust_lock();
 
@@ -265,6 +282,74 @@ 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 - 1) {
+			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,
@@ -346,6 +431,22 @@ end:
 			goto error;
 		}
 	}
+	/*
+	 * LTTNG_UST_TRACEPOINT_FIELD_LIST_GET needs to send the field
+	 * after the reply.
+	 */
+	if (lur.ret_code == USTCOMM_OK) {
+		switch (lum->cmd) {
+		case LTTNG_UST_TRACEPOINT_FIELD_LIST_GET:
+			len = ustcomm_send_unix_sock(sock,
+				&args.field_list.entry,
+				sizeof(args.field_list.entry));
+			if (len != sizeof(args.field_list.entry)) {
+				ret = -1;
+				goto error;
+			}
+		}
+	}
 	/*
 	 * We still have the memory map reference, and the fds have been
 	 * sent to the sessiond. We can therefore close those fds. Note
@@ -464,7 +565,9 @@ 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;
 
@@ -513,9 +616,9 @@ 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
@@ -527,13 +630,13 @@ 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;
 	}
@@ -647,7 +750,7 @@ 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
@@ -832,6 +935,8 @@ int get_timeout(struct timespec *constructor_timeout)
 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;
 
@@ -846,6 +951,7 @@ void __attribute__((constructor)) lttng_ust_init(void)
 	lttng_fixup_event_tls();
 	lttng_fixup_ringbuffer_tls();
 	lttng_fixup_vtid_tls();
+	lttng_fixup_nest_count_tls();
 
 	/*
 	 * We want precise control over the order in which we construct
@@ -868,15 +974,51 @@ void __attribute__((constructor)) lttng_ust_init(void)
 	if (ret) {
 		ERR("Error setting up to local apps");
 	}
-	ret = pthread_create(&local_apps.ust_listener, NULL,
-			ust_listener_thread, &local_apps);
 
+	/* A new thread created by pthread_create inherits the signal mask
+	 * from the parent. To avoid any signal being received by the
+	 * listener thread, we block all signals temporarily in the parent,
+	 * while we create the listener thread.
+	 */
+	sigfillset(&sig_all_blocked);
+	ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_parent_mask);
+	if (ret) {
+		ERR("pthread_sigmask: %s", strerror(ret));
+	}
+
+	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(&global_apps.ust_listener, NULL,
-				ust_listener_thread, &global_apps);
+		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) {
+		ERR("pthread_sigmask: %s", strerror(ret));
+	}
 
 	switch (timeout_mode) {
 	case 1:	/* timeout wait */
@@ -951,12 +1093,14 @@ 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));
 		}
 	}
 	/*
@@ -988,6 +1132,8 @@ 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);
@@ -1013,6 +1159,8 @@ 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 */
@@ -1030,6 +1178,8 @@ 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();