Fix: Don't assume that PROT_WRITE grants read permissions

[babeltrace.git] / formats / ctf / ctf.c

diff --git a/formats/ctf/ctf.c b/formats/ctf/ctf.c
index 8318a96a0781742837f9f4c754754d83c25d9f68..58b5488920d006e71aafe96b764e5f49ec7c5b6d 100644 (file)
--- a/formats/ctf/ctf.c
+++ b/formats/ctf/ctf.c
@@ -763,7 +763,7 @@ int ctf_init_pos(struct ctf_stream_pos *pos, struct bt_trace_descriptor *trace,
                pos->parent.trace = trace;
                break;
        case O_RDWR:
-               pos->prot = PROT_WRITE; /* Write has priority */
+               pos->prot = PROT_READ | PROT_WRITE;
                pos->flags = MAP_SHARED;
                pos->parent.rw_table = write_dispatch_table;
                pos->parent.event_cb = ctf_write_event;
@@ -779,7 +779,7 @@ int ctf_init_pos(struct ctf_stream_pos *pos, struct bt_trace_descriptor *trace,
 
 int ctf_fini_pos(struct ctf_stream_pos *pos)
 {
-       if (pos->prot == PROT_WRITE && pos->content_size_loc)
+       if ((pos->prot & PROT_WRITE) && pos->content_size_loc)
                *pos->content_size_loc = pos->offset;
        if (pos->base_mma) {
                int ret;
@@ -873,7 +873,7 @@ void ctf_packet_seek(struct bt_stream_pos *stream_pos, size_t index, int whence)
                assert(0);
        }
 
-       if (pos->prot == PROT_WRITE && pos->content_size_loc)
+       if ((pos->prot & PROT_WRITE) && pos->content_size_loc)
                *pos->content_size_loc = pos->offset;
 
        if (pos->base_mma) {
@@ -891,7 +891,7 @@ void ctf_packet_seek(struct bt_stream_pos *stream_pos, size_t index, int whence)
         * The caller should never ask for ctf_move_pos across packets,
         * except to get exactly at the beginning of the next packet.
         */
-       if (pos->prot == PROT_WRITE) {
+       if (pos->prot & PROT_WRITE) {
                switch (whence) {
                case SEEK_CUR:
                        /* The writer will add padding */
@@ -1001,12 +1001,14 @@ void ctf_packet_seek(struct bt_stream_pos *stream_pos, size_t index, int whence)
        }
 
        /* update trace_packet_header and stream_packet_context */
-       if (pos->prot != PROT_WRITE && file_stream->parent.trace_packet_header) {
+       if (!(pos->prot & PROT_WRITE) &&
+               file_stream->parent.trace_packet_header) {
                /* Read packet header */
                ret = generic_rw(&pos->parent, &file_stream->parent.trace_packet_header->p);
                assert(!ret);
        }
-       if (pos->prot != PROT_WRITE && file_stream->parent.stream_packet_context) {
+       if (!(pos->prot & PROT_WRITE) &&
+               file_stream->parent.stream_packet_context) {
                /* Read packet context */
                ret = generic_rw(&pos->parent, &file_stream->parent.stream_packet_context->p);
                assert(!ret);