Add safety assert() in session daemon

[lttng-tools.git] / src / bin / lttng-sessiond / kernel.c

diff --git a/src/bin/lttng-sessiond/kernel.c b/src/bin/lttng-sessiond/kernel.c
index 00172e80170c3089a9160bcd49ce8d72357107c0..32c40531d21b3e50f4d7b1851594b2ad1090ea4f 100644 (file)
--- a/src/bin/lttng-sessiond/kernel.c
+++ b/src/bin/lttng-sessiond/kernel.c
@@ -40,6 +40,9 @@ int kernel_add_channel_context(struct ltt_kernel_channel *chan,
 {
        int ret;
 
+       assert(chan);
+       assert(ctx);
+
        DBG("Adding context to channel %s", chan->channel->name);
        ret = kernctl_add_context(chan->fd, ctx);
        if (ret < 0) {
@@ -75,6 +78,8 @@ int kernel_create_session(struct ltt_session *session, int tracer_fd)
        int ret;
        struct ltt_kernel_session *lks;
 
+       assert(session);
+
        /* Allocate data structure */
        lks = trace_kernel_create_session(session->path);
        if (lks == NULL) {
@@ -118,6 +123,10 @@ int kernel_create_channel(struct ltt_kernel_session *session,
        int ret;
        struct ltt_kernel_channel *lkc;
 
+       assert(session);
+       assert(chan);
+       assert(path);
+
        /* Allocate kernel channel */
        lkc = trace_kernel_create_channel(chan, path);
        if (lkc == NULL) {
@@ -148,6 +157,7 @@ int kernel_create_channel(struct ltt_kernel_session *session,
        /* Add channel to session */
        cds_list_add(&lkc->list, &session->channel_list.head);
        session->channel_count++;
+       lkc->session = session;
 
        DBG("Kernel channel %s created (fd: %d)", lkc->channel->name, lkc->fd);
 
@@ -167,6 +177,9 @@ int kernel_create_event(struct lttng_event *ev,
        int ret;
        struct ltt_kernel_event *event;
 
+       assert(ev);
+       assert(channel);
+
        event = trace_kernel_create_event(ev);
        if (event == NULL) {
                ret = -1;
@@ -230,6 +243,8 @@ int kernel_disable_channel(struct ltt_kernel_channel *chan)
 {
        int ret;
 
+       assert(chan);
+
        ret = kernctl_disable(chan->fd);
        if (ret < 0) {
                PERROR("disable chan ioctl");
@@ -253,6 +268,8 @@ int kernel_enable_channel(struct ltt_kernel_channel *chan)
 {
        int ret;
 
+       assert(chan);
+
        ret = kernctl_enable(chan->fd);
        if (ret < 0 && errno != EEXIST) {
                PERROR("Enable kernel chan");
@@ -275,6 +292,8 @@ int kernel_enable_event(struct ltt_kernel_event *event)
 {
        int ret;
 
+       assert(event);
+
        ret = kernctl_enable(event->fd);
        if (ret < 0) {
                switch (errno) {
@@ -304,6 +323,8 @@ int kernel_disable_event(struct ltt_kernel_event *event)
 {
        int ret;
 
+       assert(event);
+
        ret = kernctl_disable(event->fd);
        if (ret < 0) {
                switch (errno) {
@@ -335,6 +356,8 @@ int kernel_open_metadata(struct ltt_kernel_session *session)
        int ret;
        struct ltt_kernel_metadata *lkm;
 
+       assert(session);
+
        /* Allocate kernel metadata */
        lkm = trace_kernel_create_metadata();
        if (lkm == NULL) {
@@ -371,6 +394,8 @@ int kernel_start_session(struct ltt_kernel_session *session)
 {
        int ret;
 
+       assert(session);
+
        ret = kernctl_start_session(session->fd);
        if (ret < 0) {
                PERROR("ioctl start session");
@@ -408,6 +433,8 @@ 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");
@@ -441,6 +468,8 @@ int kernel_flush_buffer(struct ltt_kernel_channel *channel)
        int ret;
        struct ltt_kernel_stream *stream;
 
+       assert(channel);
+
        DBG("Flush buffer for channel %s", channel->channel->name);
 
        cds_list_for_each_entry(stream, &channel->stream_list.head, list) {
@@ -463,6 +492,8 @@ int kernel_stop_session(struct ltt_kernel_session *session)
 {
        int ret;
 
+       assert(session);
+
        ret = kernctl_stop_session(session->fd);
        if (ret < 0) {
                goto error;
@@ -487,6 +518,8 @@ int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
        int ret, count = 0;
        struct ltt_kernel_stream *lks;
 
+       assert(channel);
+
        while ((ret = kernctl_create_stream(channel->fd)) >= 0) {
                lks = trace_kernel_create_stream(channel->channel->name, count);
                if (lks == NULL) {
@@ -528,6 +561,8 @@ int kernel_open_metadata_stream(struct ltt_kernel_session *session)
 {
        int ret;
 
+       assert(session);
+
        ret = kernctl_create_stream(session->metadata->fd);
        if (ret < 0) {
                PERROR("kernel create metadata stream");
@@ -556,10 +591,11 @@ ssize_t kernel_list_events(int tracer_fd, struct lttng_event **events)
        int fd, pos, ret;
        char *event;
        size_t nbmem, count = 0;
-       ssize_t size;
        FILE *fp;
        struct lttng_event *elist;
 
+       assert(events);
+
        fd = kernctl_tracepoint_list(tracer_fd);
        if (fd < 0) {
                PERROR("kernel tracepoint list");
@@ -584,7 +620,7 @@ ssize_t kernel_list_events(int tracer_fd, struct lttng_event **events)
                goto end;
        }
 
-       while ((size = fscanf(fp, "event { name = %m[^;]; };%n\n", &event, &pos)) == 1) {
+       while (fscanf(fp, "event { name = %m[^;]; };%n\n", &event, &pos) == 1) {
                if (count >= nbmem) {
                        struct lttng_event *new_elist;
 
@@ -709,3 +745,33 @@ void kernel_destroy_session(struct ltt_kernel_session *ksess)
 
        trace_kernel_destroy_session(ksess);
 }
+
+/*
+ * Destroy a kernel channel object. It does not do anything on the tracer side.
+ */
+void kernel_destroy_channel(struct ltt_kernel_channel *kchan)
+{
+       struct ltt_kernel_session *ksess = NULL;
+
+       assert(kchan);
+       assert(kchan->channel);
+
+       DBG3("Kernel destroy channel %s", kchan->channel->name);
+
+       /* Update channel count of associated session. */
+       if (kchan->session) {
+               /* Keep pointer reference so we can update it after the destroy. */
+               ksess = kchan->session;
+       }
+
+       trace_kernel_destroy_channel(kchan);
+
+       /*
+        * At this point the kernel channel is not visible anymore. This is safe
+        * since in order to work on a visible kernel session, the tracing session
+        * lock (ltt_session.lock) MUST be acquired.
+        */
+       if (ksess) {
+               ksess->channel_count--;
+       }
+}