X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fkernel.c;h=fea51b761c8ea2f0b224f2dfd2dc8589a9c8ad8b;hp=afa5e604fbefff9a9a2465fb5809cfe884d19f60;hb=799e2c4f4ecb595fcb52c3e6affd3b4ec7b5b24e;hpb=db7586006bc1a2b9057a2c108bf1e7d20fd6903f

diff --git a/src/bin/lttng-sessiond/kernel.c b/src/bin/lttng-sessiond/kernel.c
index afa5e604f..fea51b761 100644
--- a/src/bin/lttng-sessiond/kernel.c
+++ b/src/bin/lttng-sessiond/kernel.c
@@ -28,6 +28,7 @@
 #include <common/kernel-ctl/kernel-ctl.h>
 
 #include "kernel.h"
+#include "kern-modules.h"
 
 /*
  * Add context on a kernel channel.
@@ -41,7 +42,7 @@ int kernel_add_channel_context(struct ltt_kernel_channel *chan,
 	ret = kernctl_add_context(chan->fd, ctx);
 	if (ret < 0) {
 		if (errno != EEXIST) {
-			perror("add context ioctl");
+			PERROR("add context ioctl");
 		} else {
 			/* If EEXIST, we just ignore the error */
 			ret = 0;
@@ -51,7 +52,7 @@ int kernel_add_channel_context(struct ltt_kernel_channel *chan,
 
 	chan->ctx = zmalloc(sizeof(struct lttng_kernel_context));
 	if (chan->ctx == NULL) {
-		perror("zmalloc event context");
+		PERROR("zmalloc event context");
 		goto error;
 	}
 
@@ -74,13 +75,13 @@ int kernel_add_event_context(struct ltt_kernel_event *event,
 	DBG("Adding context to event %s", event->event->name);
 	ret = kernctl_add_context(event->fd, ctx);
 	if (ret < 0) {
-		perror("add context ioctl");
+		PERROR("add context ioctl");
 		goto error;
 	}
 
 	event->ctx = zmalloc(sizeof(struct lttng_kernel_context));
 	if (event->ctx == NULL) {
-		perror("zmalloc event context");
+		PERROR("zmalloc event context");
 		goto error;
 	}
 
@@ -111,7 +112,7 @@ int kernel_create_session(struct ltt_session *session, int tracer_fd)
 	/* Kernel tracer session creation */
 	ret = kernctl_create_session(tracer_fd);
 	if (ret < 0) {
-		perror("ioctl kernel create session");
+		PERROR("ioctl kernel create session");
 		goto error;
 	}
 
@@ -119,7 +120,7 @@ int kernel_create_session(struct ltt_session *session, int tracer_fd)
 	/* Prevent fd duplication after execlp() */
 	ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
 	if (ret < 0) {
-		perror("fcntl session fd");
+		PERROR("fcntl session fd");
 	}
 
 	lks->consumer_fds_sent = 0;
@@ -152,7 +153,7 @@ int kernel_create_channel(struct ltt_kernel_session *session,
 	/* Kernel tracer channel creation */
 	ret = kernctl_create_channel(session->fd, &lkc->channel->attr);
 	if (ret < 0) {
-		perror("ioctl kernel create channel");
+		PERROR("ioctl kernel create channel");
 		goto error;
 	}
 
@@ -161,7 +162,7 @@ int kernel_create_channel(struct ltt_kernel_session *session,
 	/* Prevent fd duplication after execlp() */
 	ret = fcntl(lkc->fd, F_SETFD, FD_CLOEXEC);
 	if (ret < 0) {
-		perror("fcntl session fd");
+		PERROR("fcntl session fd");
 	}
 
 	/* Add channel to session */
@@ -203,28 +204,32 @@ int kernel_create_event(struct lttng_event *ev,
 	}
 
 	/*
-	 * LTTNG_KERNEL_SYSCALL event creation will return 0 on success. However
-	 * this FD must not be added to the event list.
+	 * LTTNG_KERNEL_SYSCALL event creation will return 0 on success.
 	 */
 	if (ret == 0 && event->event->instrumentation == LTTNG_KERNEL_SYSCALL) {
 		DBG2("Kernel event syscall creation success");
-		goto end;
+		/*
+		 * We use fd == -1 to ensure that we never trigger a close of fd
+		 * 0.
+		 */
+		event->fd = -1;
+		goto add_list;
 	}
 
 	event->fd = ret;
 	/* Prevent fd duplication after execlp() */
 	ret = fcntl(event->fd, F_SETFD, FD_CLOEXEC);
 	if (ret < 0) {
-		perror("fcntl session fd");
+		PERROR("fcntl session fd");
 	}
 
+add_list:
 	/* Add event to event list */
 	cds_list_add(&event->list, &channel->events_list.head);
 	channel->event_count++;
 
 	DBG("Event %s created (fd: %d)", ev->name, event->fd);
 
-end:
 	return 0;
 
 free_event:
@@ -242,7 +247,7 @@ int kernel_disable_channel(struct ltt_kernel_channel *chan)
 
 	ret = kernctl_disable(chan->fd);
 	if (ret < 0) {
-		perror("disable chan ioctl");
+		PERROR("disable chan ioctl");
 		ret = errno;
 		goto error;
 	}
@@ -265,7 +270,7 @@ int kernel_enable_channel(struct ltt_kernel_channel *chan)
 
 	ret = kernctl_enable(chan->fd);
 	if (ret < 0 && errno != EEXIST) {
-		perror("Enable kernel chan");
+		PERROR("Enable kernel chan");
 		goto error;
 	}
 
@@ -287,7 +292,7 @@ int kernel_enable_event(struct ltt_kernel_event *event)
 
 	ret = kernctl_enable(event->fd);
 	if (ret < 0 && errno != EEXIST) {
-		perror("enable kernel event");
+		PERROR("enable kernel event");
 		goto error;
 	}
 
@@ -309,7 +314,7 @@ int kernel_disable_event(struct ltt_kernel_event *event)
 
 	ret = kernctl_disable(event->fd);
 	if (ret < 0 && errno != EEXIST) {
-		perror("disable kernel event");
+		PERROR("disable kernel event");
 		goto error;
 	}
 
@@ -347,7 +352,7 @@ int kernel_open_metadata(struct ltt_kernel_session *session, char *path)
 	/* Prevent fd duplication after execlp() */
 	ret = fcntl(lkm->fd, F_SETFD, FD_CLOEXEC);
 	if (ret < 0) {
-		perror("fcntl session fd");
+		PERROR("fcntl session fd");
 	}
 
 	session->metadata = lkm;
@@ -369,7 +374,7 @@ int kernel_start_session(struct ltt_kernel_session *session)
 
 	ret = kernctl_start_session(session->fd);
 	if (ret < 0) {
-		perror("ioctl start session");
+		PERROR("ioctl start session");
 		goto error;
 	}
 
@@ -392,7 +397,7 @@ void kernel_wait_quiescent(int fd)
 
 	ret = kernctl_wait_quiescent(fd);
 	if (ret < 0) {
-		perror("wait quiescent ioctl");
+		PERROR("wait quiescent ioctl");
 		ERR("Kernel quiescent wait failed");
 	}
 }
@@ -406,7 +411,7 @@ int kernel_calibrate(int fd, struct lttng_kernel_calibrate *calibrate)
 
 	ret = kernctl_calibrate(fd, calibrate);
 	if (ret < 0) {
-		perror("calibrate ioctl");
+		PERROR("calibrate ioctl");
 		return -1;
 	}
 
@@ -443,7 +448,7 @@ int kernel_flush_buffer(struct ltt_kernel_channel *channel)
 		DBG("Flushing channel stream %d", stream->fd);
 		ret = kernctl_buffer_flush(stream->fd);
 		if (ret < 0) {
-			perror("ioctl");
+			PERROR("ioctl");
 			ERR("Fail to flush buffer for stream %d (ret: %d)",
 					stream->fd, ret);
 		}
@@ -483,10 +488,13 @@ int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
 	int ret;
 	struct ltt_kernel_stream *lks;
 
-	while ((ret = kernctl_create_stream(channel->fd)) > 0) {
+	while ((ret = kernctl_create_stream(channel->fd)) >= 0) {
 		lks = trace_kernel_create_stream();
 		if (lks == NULL) {
-			close(ret);
+			ret = close(ret);
+			if (ret) {
+				PERROR("close");
+			}
 			goto error;
 		}
 
@@ -494,13 +502,13 @@ int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
 		/* Prevent fd duplication after execlp() */
 		ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
 		if (ret < 0) {
-			perror("fcntl session fd");
+			PERROR("fcntl session fd");
 		}
 
 		ret = asprintf(&lks->pathname, "%s/%s_%d",
 				channel->pathname, channel->channel->name, channel->stream_count);
 		if (ret < 0) {
-			perror("asprintf kernel create stream");
+			PERROR("asprintf kernel create stream");
 			goto error;
 		}
 
@@ -527,7 +535,7 @@ int kernel_open_metadata_stream(struct ltt_kernel_session *session)
 
 	ret = kernctl_create_stream(session->metadata->fd);
 	if (ret < 0) {
-		perror("kernel create metadata stream");
+		PERROR("kernel create metadata stream");
 		goto error;
 	}
 
@@ -536,7 +544,7 @@ int kernel_open_metadata_stream(struct ltt_kernel_session *session)
 	/* Prevent fd duplication after execlp() */
 	ret = fcntl(session->metadata_stream_fd, F_SETFD, FD_CLOEXEC);
 	if (ret < 0) {
-		perror("fcntl session fd");
+		PERROR("fcntl session fd");
 	}
 
 	return 0;
@@ -550,7 +558,7 @@ error:
  */
 ssize_t kernel_list_events(int tracer_fd, struct lttng_event **events)
 {
-	int fd, pos;
+	int fd, pos, ret;
 	char *event;
 	size_t nbmem, count = 0;
 	ssize_t size;
@@ -559,13 +567,13 @@ ssize_t kernel_list_events(int tracer_fd, struct lttng_event **events)
 
 	fd = kernctl_tracepoint_list(tracer_fd);
 	if (fd < 0) {
-		perror("kernel tracepoint list");
+		PERROR("kernel tracepoint list");
 		goto error;
 	}
 
 	fp = fdopen(fd, "r");
 	if (fp == NULL) {
-		perror("kernel tracepoint list fdopen");
+		PERROR("kernel tracepoint list fdopen");
 		goto error_fp;
 	}
 
@@ -584,7 +592,7 @@ ssize_t kernel_list_events(int tracer_fd, struct lttng_event **events)
 			nbmem <<= 1;
 			elist = realloc(elist, nbmem * sizeof(struct lttng_event));
 			if (elist == NULL) {
-				perror("realloc list events");
+				PERROR("realloc list events");
 				count = -ENOMEM;
 				goto end;
 			}
@@ -598,11 +606,82 @@ ssize_t kernel_list_events(int tracer_fd, struct lttng_event **events)
 	*events = elist;
 	DBG("Kernel list events done (%zu events)", count);
 end:
-	fclose(fp);	/* closes both fp and fd */
+	ret = fclose(fp);	/* closes both fp and fd */
+	if (ret) {
+		PERROR("fclose");
+	}
 	return count;
 
 error_fp:
-	close(fd);
+	ret = close(fd);
+	if (ret) {
+		PERROR("close");
+	}
 error:
 	return -1;
 }
+
+/*
+ * Get kernel version and validate it.
+ */
+int kernel_validate_version(int tracer_fd)
+{
+	int ret;
+	struct lttng_kernel_tracer_version version;
+
+	ret = kernctl_tracer_version(tracer_fd, &version);
+	if (ret < 0) {
+		ERR("Failed at getting the lttng-modules version");
+		goto error;
+	}
+
+	/* Validate version */
+	if (version.major != KERN_MODULES_PRE_MAJOR
+		&& version.major != KERN_MODULES_MAJOR) {
+		goto error_version;
+	}
+
+	DBG2("Kernel tracer version validated (major version %d)", version.major);
+	return 0;
+
+error_version:
+	ERR("Kernel major version %d is not compatible (supporting <= %d)",
+			version.major, KERN_MODULES_MAJOR)
+	ret = -1;
+
+error:
+	return ret;
+}
+
+/*
+ * Kernel work-arounds called at the start of sessiond main().
+ */
+int init_kernel_workarounds(void)
+{
+	int ret;
+	FILE *fp;
+
+	/*
+	 * boot_id needs to be read once before being used concurrently
+	 * to deal with a Linux kernel race. A fix is proposed for
+	 * upstream, but the work-around is needed for older kernels.
+	 */
+	fp = fopen("/proc/sys/kernel/random/boot_id", "r");
+	if (!fp) {
+		goto end_boot_id;
+	}
+	while (!feof(fp)) {
+		char buf[37] = "";
+
+		ret = fread(buf, 1, sizeof(buf), fp);
+		if (ret < 0) {
+			/* Ignore error, we don't really care */
+		}
+	}
+	ret = fclose(fp);
+	if (ret) {
+		PERROR("fclose");
+	}
+end_boot_id:
+	return 0;
+}