Fix: don't dereference NULL pointers

[lttng-ust.git] / liblttng-ust-ctl / ustctl.c

diff --git a/liblttng-ust-ctl/ustctl.c b/liblttng-ust-ctl/ustctl.c
index ca17255d914e9b65346685e4e1988382d5e18d0b..6b6f295b38bd81ff4ce3e26ad47f7ea37c351fc0 100644 (file)
--- a/liblttng-ust-ctl/ustctl.c
+++ b/liblttng-ust-ctl/ustctl.c
@@ -32,6 +32,7 @@
 #include "../libringbuffer/frontend.h"
 #include "../liblttng-ust/wait.h"
 #include "../liblttng-ust/lttng-rb-clients.h"
+#include "../liblttng-ust/clock.h"
 
 /*
  * Number of milliseconds to retry before failing metadata writes on
@@ -1340,6 +1341,8 @@ int ustctl_get_mmap_read_offset(struct ustctl_consumer_stream *stream,
        unsigned long sb_bindex;
        struct lttng_ust_lib_ring_buffer *buf;
        struct ustctl_consumer_channel *consumer_chan;
+       struct lttng_ust_lib_ring_buffer_backend_pages_shmp *barray_idx;
+       struct lttng_ust_lib_ring_buffer_backend_pages *pages;
 
        if (!stream)
                return -EINVAL;
@@ -1350,8 +1353,14 @@ int ustctl_get_mmap_read_offset(struct ustctl_consumer_stream *stream,
                return -EINVAL;
        sb_bindex = subbuffer_id_get_index(&chan->backend.config,
                                        buf->backend.buf_rsb.id);
-       *off = shmp(consumer_chan->chan->handle,
-               shmp_index(consumer_chan->chan->handle, buf->backend.array, sb_bindex)->shmp)->mmap_offset;
+       barray_idx = shmp_index(consumer_chan->chan->handle, buf->backend.array,
+                       sb_bindex);
+       if (!barray_idx)
+               return -EINVAL;
+       pages = shmp(consumer_chan->chan->handle, barray_idx->shmp);
+       if (!pages)
+               return -EINVAL;
+       *off = pages->mmap_offset;
        return 0;
 }
 
@@ -1517,6 +1526,8 @@ struct lttng_ust_client_lib_ring_buffer_client_cb *get_client_cb(
        struct lttng_ust_client_lib_ring_buffer_client_cb *client_cb;
 
        chan = shmp(handle, buf->backend.chan);
+       if (!chan)
+               return NULL;
        config = &chan->backend.config;
        if (!config->cb_ptr)
                return NULL;
@@ -2003,6 +2014,7 @@ static __attribute__((constructor))
 void ustctl_init(void)
 {
        init_usterr();
+       lttng_ust_clock_init();
        lttng_ring_buffer_metadata_client_init();
        lttng_ring_buffer_client_overwrite_init();
        lttng_ring_buffer_client_overwrite_rt_init();