X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fkernel.c;h=535a5b8e8c4035918f0e2665ac0af8f0e7ad8eda;hb=e1f3997aa650554880105d787a864653add7c070;hp=bf9f8b623288eb2e7eb58652bb5f26493ecf399e;hpb=d0ae4ea864f84fa2456563abb20fe42e5cc29625;p=lttng-tools.git

diff --git a/src/bin/lttng-sessiond/kernel.c b/src/bin/lttng-sessiond/kernel.c
index bf9f8b623..535a5b8e8 100644
--- a/src/bin/lttng-sessiond/kernel.c
+++ b/src/bin/lttng-sessiond/kernel.c
@@ -15,9 +15,7 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#define _GNU_SOURCE
 #define _LGPL_SOURCE
-#include <errno.h>
 #include <fcntl.h>
 #include <stdlib.h>
 #include <stdio.h>
@@ -36,8 +34,16 @@
 #include "kern-modules.h"
 #include "utils.h"
 
+/*
+ * Key used to reference a channel between the sessiond and the consumer. This
+ * is only read and updated with the session_list lock held.
+ */
+static uint64_t next_kernel_channel_key;
+
 /*
  * Add context on a kernel channel.
+ *
+ * Assumes the ownership of ctx.
  */
 int kernel_add_channel_context(struct ltt_kernel_channel *chan,
 		struct ltt_kernel_context *ctx)
@@ -50,20 +56,31 @@ int kernel_add_channel_context(struct ltt_kernel_channel *chan,
 	DBG("Adding context to channel %s", chan->channel->name);
 	ret = kernctl_add_context(chan->fd, &ctx->ctx);
 	if (ret < 0) {
-		if (errno != EEXIST) {
-			PERROR("add context ioctl");
-		} else {
+		switch (-ret) {
+		case ENOSYS:
+			/* Exists but not available for this kernel */
+			ret = LTTNG_ERR_KERN_CONTEXT_UNAVAILABLE;
+			goto error;
+		case EEXIST:
 			/* If EEXIST, we just ignore the error */
 			ret = 0;
+			goto end;
+		default:
+			PERROR("add context ioctl");
+			ret = LTTNG_ERR_KERN_CONTEXT_FAIL;
+			goto error;
 		}
-		goto error;
 	}
+	ret = 0;
 
+end:
 	cds_list_add_tail(&ctx->list, &chan->ctx_list);
-
-	return 0;
-
+	ctx->in_list = true;
+	ctx = NULL;
 error:
+	if (ctx) {
+		trace_kernel_destroy_context(ctx);
+	}
 	return ret;
 }
 
@@ -158,8 +175,10 @@ int kernel_create_channel(struct ltt_kernel_session *session,
 	cds_list_add(&lkc->list, &session->channel_list.head);
 	session->channel_count++;
 	lkc->session = session;
+	lkc->key = ++next_kernel_channel_key;
 
-	DBG("Kernel channel %s created (fd: %d)", lkc->channel->name, lkc->fd);
+	DBG("Kernel channel %s created (fd: %d, key: %" PRIu64 ")",
+			lkc->channel->name, lkc->fd, lkc->key);
 
 	return 0;
 
@@ -177,7 +196,9 @@ error:
  * We own filter_expression and filter.
  */
 int kernel_create_event(struct lttng_event *ev,
-		struct ltt_kernel_channel *channel)
+		struct ltt_kernel_channel *channel,
+		char *filter_expression,
+		struct lttng_filter_bytecode *filter)
 {
 	int ret;
 	struct ltt_kernel_event *event;
@@ -185,7 +206,9 @@ int kernel_create_event(struct lttng_event *ev,
 	assert(ev);
 	assert(channel);
 
-	event = trace_kernel_create_event(ev);
+	/* We pass ownership of filter_expression and filter */
+	event = trace_kernel_create_event(ev, filter_expression,
+			filter);
 	if (event == NULL) {
 		ret = -1;
 		goto error;
@@ -193,7 +216,7 @@ int kernel_create_event(struct lttng_event *ev,
 
 	ret = kernctl_create_event(channel->fd, event->event);
 	if (ret < 0) {
-		switch (errno) {
+		switch (-ret) {
 		case EEXIST:
 			break;
 		case ENOSYS:
@@ -205,7 +228,6 @@ int kernel_create_event(struct lttng_event *ev,
 		default:
 			PERROR("create event ioctl");
 		}
-		ret = -errno;
 		goto free_event;
 	}
 
@@ -217,6 +239,26 @@ int kernel_create_event(struct lttng_event *ev,
 		PERROR("fcntl session fd");
 	}
 
+	if (filter) {
+		ret = kernctl_filter(event->fd, filter);
+		if (ret) {
+			goto filter_error;
+		}
+	}
+
+	ret = kernctl_enable(event->fd);
+	if (ret < 0) {
+		switch (-ret) {
+		case EEXIST:
+			ret = LTTNG_ERR_KERN_EVENT_EXIST;
+			break;
+		default:
+			PERROR("enable kernel event");
+			break;
+		}
+		goto enable_error;
+	}
+
 	/* Add event to event list */
 	cds_list_add(&event->list, &channel->events_list.head);
 	channel->event_count++;
@@ -225,6 +267,16 @@ int kernel_create_event(struct lttng_event *ev,
 
 	return 0;
 
+enable_error:
+filter_error:
+	{
+		int closeret;
+
+		closeret = close(event->fd);
+		if (closeret) {
+			PERROR("close event fd");
+		}
+	}
 free_event:
 	free(event);
 error:
@@ -243,12 +295,12 @@ int kernel_disable_channel(struct ltt_kernel_channel *chan)
 	ret = kernctl_disable(chan->fd);
 	if (ret < 0) {
 		PERROR("disable chan ioctl");
-		ret = errno;
 		goto error;
 	}
 
 	chan->enabled = 0;
-	DBG("Kernel channel %s disabled (fd: %d)", chan->channel->name, chan->fd);
+	DBG("Kernel channel %s disabled (fd: %d, key: %" PRIu64 ")",
+			chan->channel->name, chan->fd, chan->key);
 
 	return 0;
 
@@ -266,13 +318,14 @@ int kernel_enable_channel(struct ltt_kernel_channel *chan)
 	assert(chan);
 
 	ret = kernctl_enable(chan->fd);
-	if (ret < 0 && errno != EEXIST) {
+	if (ret < 0 && ret != -EEXIST) {
 		PERROR("Enable kernel chan");
 		goto error;
 	}
 
 	chan->enabled = 1;
-	DBG("Kernel channel %s enabled (fd: %d)", chan->channel->name, chan->fd);
+	DBG("Kernel channel %s enabled (fd: %d, key: %" PRIu64 ")",
+			chan->channel->name, chan->fd, chan->key);
 
 	return 0;
 
@@ -291,7 +344,7 @@ int kernel_enable_event(struct ltt_kernel_event *event)
 
 	ret = kernctl_enable(event->fd);
 	if (ret < 0) {
-		switch (errno) {
+		switch (-ret) {
 		case EEXIST:
 			ret = LTTNG_ERR_KERN_EVENT_EXIST;
 			break;
@@ -322,7 +375,7 @@ int kernel_disable_event(struct ltt_kernel_event *event)
 
 	ret = kernctl_disable(event->fd);
 	if (ret < 0) {
-		switch (errno) {
+		switch (-ret) {
 		case EEXIST:
 			ret = LTTNG_ERR_KERN_EVENT_EXIST;
 			break;
@@ -345,16 +398,46 @@ error:
 
 int kernel_track_pid(struct ltt_kernel_session *session, int pid)
 {
+	int ret;
+
 	DBG("Kernel track PID %d for session id %" PRIu64 ".",
 			pid, session->id);
-	return kernctl_track_pid(session->fd, pid);
+	ret = kernctl_track_pid(session->fd, pid);
+	if (!ret) {
+		return LTTNG_OK;
+	}
+	switch (-ret) {
+	case EINVAL:
+		return LTTNG_ERR_INVALID;
+	case ENOMEM:
+		return LTTNG_ERR_NOMEM;
+	case EEXIST:
+		return LTTNG_ERR_PID_TRACKED;
+	default:
+		return LTTNG_ERR_UNK;
+	}
 }
 
 int kernel_untrack_pid(struct ltt_kernel_session *session, int pid)
 {
+	int ret;
+
 	DBG("Kernel untrack PID %d for session id %" PRIu64 ".",
 			pid, session->id);
-	return kernctl_untrack_pid(session->fd, pid);
+	ret = kernctl_untrack_pid(session->fd, pid);
+	if (!ret) {
+		return LTTNG_OK;
+	}
+	switch (-ret) {
+	case EINVAL:
+		return LTTNG_ERR_INVALID;
+	case ENOMEM:
+		return LTTNG_ERR_NOMEM;
+	case ENOENT:
+		return LTTNG_ERR_PID_NOT_TRACKED;
+	default:
+		return LTTNG_ERR_UNK;
+	}
 }
 
 ssize_t kernel_list_tracker_pids(struct ltt_kernel_session *session,
@@ -509,25 +592,6 @@ void kernel_wait_quiescent(int fd)
 	}
 }
 
-/*
- * Kernel calibrate
- */
-int kernel_calibrate(int fd, struct lttng_kernel_calibrate *calibrate)
-{
-	int ret;
-
-	assert(calibrate);
-
-	ret = kernctl_calibrate(fd, calibrate);
-	if (ret < 0) {
-		PERROR("calibrate ioctl");
-		return -1;
-	}
-
-	return 0;
-}
-
-
 /*
  *  Force flush buffer of metadata.
  */
@@ -596,17 +660,22 @@ error:
  * Open stream of channel, register it to the kernel tracer and add it
  * to the stream list of the channel.
  *
+ * Note: given that the streams may appear in random order wrt CPU
+ * number (e.g. cpu hotplug), the index value of the stream number in
+ * the stream name is not necessarily linked to the CPU number.
+ *
  * Return the number of created stream. Else, a negative value.
  */
 int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
 {
-	int ret, count = 0;
+	int ret;
 	struct ltt_kernel_stream *lks;
 
 	assert(channel);
 
 	while ((ret = kernctl_create_stream(channel->fd)) >= 0) {
-		lks = trace_kernel_create_stream(channel->channel->name, count);
+		lks = trace_kernel_create_stream(channel->channel->name,
+				channel->stream_count);
 		if (lks == NULL) {
 			ret = close(ret);
 			if (ret) {
@@ -625,13 +694,10 @@ int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
 		lks->tracefile_size = channel->channel->attr.tracefile_size;
 		lks->tracefile_count = channel->channel->attr.tracefile_count;
 
-		/* Add stream to channe stream list */
+		/* Add stream to channel stream list */
 		cds_list_add(&lks->list, &channel->stream_list.head);
 		channel->stream_count++;
 
-		/* Increment counter which represent CPU number. */
-		count++;
-
 		DBG("Kernel stream %s created (fd: %d, state: %d)", lks->name, lks->fd,
 				lks->state);
 	}
@@ -766,7 +832,7 @@ int kernel_validate_version(int tracer_fd)
 
 	ret = kernctl_tracer_version(tracer_fd, &version);
 	if (ret < 0) {
-		ERR("Failed at getting the lttng-modules version");
+		ERR("Failed to retrieve the lttng-modules version");
 		goto error;
 	}
 
@@ -778,11 +844,11 @@ int kernel_validate_version(int tracer_fd)
 	}
 	ret = kernctl_tracer_abi_version(tracer_fd, &abi_version);
 	if (ret < 0) {
-		ERR("Failed at getting lttng-modules ABI version");
+		ERR("Failed to retrieve lttng-modules ABI version");
 		goto error;
 	}
 	if (abi_version.major != LTTNG_MODULES_ABI_MAJOR_VERSION) {
-		ERR("Kernel tracer ABI version (%d.%d) is not compatible with expected ABI major version (%d.*)",
+		ERR("Kernel tracer ABI version (%d.%d) does not match the expected ABI major version (%d.*)",
 			abi_version.major, abi_version.minor,
 			LTTNG_MODULES_ABI_MAJOR_VERSION);
 		goto error;
@@ -796,6 +862,7 @@ error_version:
 	ret = -1;
 
 error:
+	ERR("Kernel tracer version check failed; kernel tracing will not be available");
 	return ret;
 }
 
@@ -972,12 +1039,10 @@ int kernel_snapshot_record(struct ltt_kernel_session *ksess,
 
 		/* For each channel, ask the consumer to snapshot it. */
 		cds_list_for_each_entry(chan, &ksess->channel_list.head, list) {
-			pthread_mutex_lock(socket->lock);
 			ret = consumer_snapshot_channel(socket, chan->fd, output, 0,
 					ksess->uid, ksess->gid,
 					DEFAULT_KERNEL_TRACE_DIR, wait,
 					nb_packets_per_stream);
-			pthread_mutex_unlock(socket->lock);
 			if (ret < 0) {
 				ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
 				(void) kernel_consumer_destroy_metadata(socket,
@@ -987,11 +1052,9 @@ int kernel_snapshot_record(struct ltt_kernel_session *ksess,
 		}
 
 		/* Snapshot metadata, */
-		pthread_mutex_lock(socket->lock);
 		ret = consumer_snapshot_channel(socket, ksess->metadata->fd, output,
 				1, ksess->uid, ksess->gid,
 				DEFAULT_KERNEL_TRACE_DIR, wait, 0);
-		pthread_mutex_unlock(socket->lock);
 		if (ret < 0) {
 			ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
 			goto error_consumer;
@@ -1037,3 +1100,35 @@ int kernel_syscall_mask(int chan_fd, char **syscall_mask, uint32_t *nr_bits)
 
 	return kernctl_syscall_mask(chan_fd, syscall_mask, nr_bits);
 }
+
+/*
+ * Check for the support of the RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS via abi
+ * version number.
+ *
+ * Return 1 on success, 0 when feature is not supported, negative value in case
+ * of errors.
+ */
+int kernel_supports_ring_buffer_snapshot_sample_positions(int tracer_fd)
+{
+	int ret = 0; // Not supported by default
+	struct lttng_kernel_tracer_abi_version abi;
+
+	ret = kernctl_tracer_abi_version(tracer_fd, &abi);
+	if (ret < 0) {
+		ERR("Failed to retrieve lttng-modules ABI version");
+		goto error;
+	}
+
+	/*
+	 * RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS was introduced in 2.3
+	 */
+	if (abi.major >= 2 && abi.minor >= 3) {
+		/* Supported */
+		ret = 1;
+	} else {
+		/* Not supported */
+		ret = 0;
+	}
+error:
+	return ret;
+}