Fix: dereference before null check

Found by Coverity:
CID 1090602 (#1 of 1): Dereference before null check (REVERSE_INULL)
check_after_deref: Null-checking "stream" suggests that it may be null,
but it has already been dereferenced on all paths leading to the check

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/liblttng-ust-ctl/ustctl.c b/liblttng-ust-ctl/ustctl.c
index bc3ea9b12266531be1a5b1d7f760b06192ff93d9..854d8ae391d25c43a2179193c99dc398a9ee7ef4 100644 (file)
--- a/liblttng-ust-ctl/ustctl.c
+++ b/liblttng-ust-ctl/ustctl.c
@@ -1523,11 +1523,13 @@ int ustctl_get_timestamp_begin(struct ustctl_consumer_stream *stream,
                uint64_t *timestamp_begin)
 {
        struct lttng_ust_client_lib_ring_buffer_client_cb *client_cb;
-       struct lttng_ust_lib_ring_buffer *buf = stream->buf;
-       struct lttng_ust_shm_handle *handle = stream->chan->chan->handle;
+       struct lttng_ust_lib_ring_buffer *buf;
+       struct lttng_ust_shm_handle *handle;
 
        if (!stream || !timestamp_begin)
                return -EINVAL;
+       buf = stream->buf;
+       handle = stream->chan->chan->handle;
        client_cb = get_client_cb(buf, handle);
        if (!client_cb)
                return -ENOSYS;
@@ -1538,11 +1540,13 @@ int ustctl_get_timestamp_end(struct ustctl_consumer_stream *stream,
        uint64_t *timestamp_end)
 {
        struct lttng_ust_client_lib_ring_buffer_client_cb *client_cb;
-       struct lttng_ust_lib_ring_buffer *buf = stream->buf;
-       struct lttng_ust_shm_handle *handle = stream->chan->chan->handle;
+       struct lttng_ust_lib_ring_buffer *buf;
+       struct lttng_ust_shm_handle *handle;
 
        if (!stream || !timestamp_end)
                return -EINVAL;
+       buf = stream->buf;
+       handle = stream->chan->chan->handle;
        client_cb = get_client_cb(buf, handle);
        if (!client_cb)
                return -ENOSYS;
@@ -1553,11 +1557,13 @@ int ustctl_get_events_discarded(struct ustctl_consumer_stream *stream,
        uint64_t *events_discarded)
 {
        struct lttng_ust_client_lib_ring_buffer_client_cb *client_cb;
-       struct lttng_ust_lib_ring_buffer *buf = stream->buf;
-       struct lttng_ust_shm_handle *handle = stream->chan->chan->handle;
+       struct lttng_ust_lib_ring_buffer *buf;
+       struct lttng_ust_shm_handle *handle;
 
        if (!stream || !events_discarded)
                return -EINVAL;
+       buf = stream->buf;
+       handle = stream->chan->chan->handle;
        client_cb = get_client_cb(buf, handle);
        if (!client_cb)
                return -ENOSYS;
@@ -1568,11 +1574,13 @@ int ustctl_get_content_size(struct ustctl_consumer_stream *stream,
        uint64_t *content_size)
 {
        struct lttng_ust_client_lib_ring_buffer_client_cb *client_cb;
-       struct lttng_ust_lib_ring_buffer *buf = stream->buf;
-       struct lttng_ust_shm_handle *handle = stream->chan->chan->handle;
+       struct lttng_ust_lib_ring_buffer *buf;
+       struct lttng_ust_shm_handle *handle;
 
        if (!stream || !content_size)
                return -EINVAL;
+       buf = stream->buf;
+       handle = stream->chan->chan->handle;
        client_cb = get_client_cb(buf, handle);
        if (!client_cb)
                return -ENOSYS;
@@ -1583,11 +1591,13 @@ int ustctl_get_packet_size(struct ustctl_consumer_stream *stream,
        uint64_t *packet_size)
 {
        struct lttng_ust_client_lib_ring_buffer_client_cb *client_cb;
-       struct lttng_ust_lib_ring_buffer *buf = stream->buf;
-       struct lttng_ust_shm_handle *handle = stream->chan->chan->handle;
+       struct lttng_ust_lib_ring_buffer *buf;
+       struct lttng_ust_shm_handle *handle;
 
        if (!stream || !packet_size)
                return -EINVAL;
+       buf = stream->buf;
+       handle = stream->chan->chan->handle;
        client_cb = get_client_cb(buf, handle);
        if (!client_cb)
                return -ENOSYS;
@@ -1598,11 +1608,13 @@ int ustctl_get_stream_id(struct ustctl_consumer_stream *stream,
                uint64_t *stream_id)
 {
        struct lttng_ust_client_lib_ring_buffer_client_cb *client_cb;
-       struct lttng_ust_lib_ring_buffer *buf = stream->buf;
-       struct lttng_ust_shm_handle *handle = stream->chan->chan->handle;
+       struct lttng_ust_lib_ring_buffer *buf;
+       struct lttng_ust_shm_handle *handle;
 
        if (!stream || !stream_id)
                return -EINVAL;
+       buf = stream->buf;
+       handle = stream->chan->chan->handle;
        client_cb = get_client_cb(buf, handle);
        if (!client_cb)
                return -ENOSYS;
@@ -1613,11 +1625,13 @@ int ustctl_get_current_timestamp(struct ustctl_consumer_stream *stream,
                uint64_t *ts)
 {
        struct lttng_ust_client_lib_ring_buffer_client_cb *client_cb;
-       struct lttng_ust_lib_ring_buffer *buf = stream->buf;
-       struct lttng_ust_shm_handle *handle = stream->chan->chan->handle;
+       struct lttng_ust_lib_ring_buffer *buf;
+       struct lttng_ust_shm_handle *handle;
 
        if (!stream || !ts)
                return -EINVAL;
+       buf = stream->buf;
+       handle = stream->chan->chan->handle;
        client_cb = get_client_cb(buf, handle);
        if (!client_cb || !client_cb->current_timestamp)
                return -ENOSYS;