Fix: report truncated files while reading

When index files are available, this ensures we report the issue
properly before mapping a truncated packet rather than hitting a
SIGBUS.

For traces without index files, remove the check that was done at
index creation, and use the new check done when mapping the packet
instead. This ensures babeltrace can print stream data prior to the
truncated packet for this stream.

TODO: What is _not_ done in this patch is changing handling of truncated
packets: this should be treated as a warning rather than an error, so
processing of other streams continue.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Jonathan Rajotte-Julien <jonathan.rajotte-julien@efficios.com>
CC: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

diff --git a/formats/ctf/ctf.c b/formats/ctf/ctf.c
index 5d22d9e44de2574391fb157d3739db7a2c3b8b03..5b6e3b90cf886e559b05cfb6fd1992e5805b6bef 100644 (file)
--- a/formats/ctf/ctf.c
+++ b/formats/ctf/ctf.c
@@ -1174,6 +1174,14 @@ void ctf_packet_seek(struct bt_stream_pos *stream_pos, size_t index, int whence)
                                goto end;
                        }
                }
+
+               if (packet_index->packet_size > ((uint64_t) pos->file_length - packet_index->offset) * CHAR_BIT) {
+                       fprintf(stderr, "[error] Packet size (%" PRIu64 " bits) is larger than remaining file size (%" PRIu64 " bits).\n",
+                               packet_index->packet_size, ((uint64_t) pos->file_length - packet_index->offset) * CHAR_BIT);
+                       ret = -1;
+                       goto end;
+               }
+
                pos->content_size = packet_index->content_size;
                pos->packet_size = packet_index->packet_size;
                pos->mmap_offset = packet_index->offset;
@@ -1702,8 +1710,7 @@ int stream_assign_class(struct ctf_trace *td,
 static
 int create_stream_one_packet_index(struct ctf_stream_pos *pos,
                        struct ctf_trace *td,
-                       struct ctf_file_stream *file_stream,
-                       size_t filesize)
+                       struct ctf_file_stream *file_stream)
 {
        struct packet_index packet_index;
        uint64_t stream_id = 0;
@@ -1718,8 +1725,8 @@ begin:
                first_packet = 1;
        }
 
-       if (filesize - pos->mmap_offset < (packet_map_len >> LOG2_CHAR_BIT)) {
-               packet_map_len = (filesize - pos->mmap_offset) << LOG2_CHAR_BIT;
+       if (pos->file_length - pos->mmap_offset < (packet_map_len >> LOG2_CHAR_BIT)) {
+               packet_map_len = (pos->file_length - pos->mmap_offset) << LOG2_CHAR_BIT;
        }
 
        if (pos->base_mma) {
@@ -1837,7 +1844,7 @@ begin:
                        packet_index.packet_size = bt_get_unsigned_int(field);
                } else {
                        /* Use file size for packet size */
-                       packet_index.packet_size = filesize * CHAR_BIT;
+                       packet_index.packet_size = pos->file_length * CHAR_BIT;
                }
 
                /* read content size from header */
@@ -1849,7 +1856,7 @@ begin:
                        packet_index.content_size = bt_get_unsigned_int(field);
                } else {
                        /* Use packet size if non-zero, else file size */
-                       packet_index.content_size = packet_index.packet_size ? : filesize * CHAR_BIT;
+                       packet_index.content_size = packet_index.packet_size ? : pos->file_length * CHAR_BIT;
                }
 
                /* read timestamp begin from header */
@@ -1906,9 +1913,9 @@ begin:
                }
        } else {
                /* Use file size for packet size */
-               packet_index.packet_size = filesize * CHAR_BIT;
+               packet_index.packet_size = pos->file_length * CHAR_BIT;
                /* Use packet size if non-zero, else file size */
-               packet_index.content_size = packet_index.packet_size ? : filesize * CHAR_BIT;
+               packet_index.content_size = packet_index.packet_size ? : pos->file_length * CHAR_BIT;
        }
 
        /* Validate content size and packet size values */
@@ -1918,12 +1925,6 @@ begin:
                return -EINVAL;
        }
 
-       if (packet_index.packet_size > ((uint64_t) filesize - packet_index.offset) * CHAR_BIT) {
-               fprintf(stderr, "[error] Packet size (%" PRIu64 " bits) is larger than remaining file size (%" PRIu64 " bits).\n",
-                       packet_index.packet_size, ((uint64_t) filesize - packet_index.offset) * CHAR_BIT);
-               return -EINVAL;
-       }
-
        if (packet_index.content_size < pos->offset) {
                fprintf(stderr, "[error] Invalid CTF stream: content size is smaller than packet headers.\n");
                return -EINVAL;
@@ -1946,7 +1947,7 @@ begin:
 
        /* Retry with larger mapping */
 retry:
-       if (packet_map_len == ((filesize - pos->mmap_offset) << LOG2_CHAR_BIT)) {
+       if (packet_map_len == ((pos->file_length - pos->mmap_offset) << LOG2_CHAR_BIT)) {
                /*
                 * Reached EOF, but still expecting header/context data.
                 */
@@ -1969,17 +1970,12 @@ int create_stream_packet_index(struct ctf_trace *td,
                        struct ctf_file_stream *file_stream)
 {
        struct ctf_stream_pos *pos;
-       struct stat filestats;
        int ret;
 
        pos = &file_stream->pos;
 
-       ret = fstat(pos->fd, &filestats);
-       if (ret < 0)
-               return ret;
-
        /* Deal with empty files */
-       if (!filestats.st_size) {
+       if (!pos->file_length) {
                if (file_stream->parent.trace_packet_header
                                || file_stream->parent.stream_packet_context) {
                        /*
@@ -2002,9 +1998,8 @@ int create_stream_packet_index(struct ctf_trace *td,
                }
        }
 
-       for (pos->mmap_offset = 0; pos->mmap_offset < filestats.st_size; ) {
-               ret = create_stream_one_packet_index(pos, td, file_stream,
-                       filestats.st_size);
+       for (pos->mmap_offset = 0; pos->mmap_offset < pos->file_length; ) {
+               ret = create_stream_one_packet_index(pos, td, file_stream);
                if (ret)
                        return ret;
        }
@@ -2189,6 +2184,7 @@ int ctf_open_file_stream_read(struct ctf_trace *td, const char *path, int flags,
        file_stream->pos.last_offset = LAST_OFFSET_POISON;
        file_stream->pos.fd = -1;
        file_stream->pos.index_fp = NULL;
+       file_stream->pos.file_length = statbuf.st_size;
 
        strncpy(file_stream->parent.path, path, PATH_MAX);
        file_stream->parent.path[PATH_MAX - 1] = '\0';

diff --git a/include/babeltrace/ctf/types.h b/include/babeltrace/ctf/types.h
index 59ce99811f73993457ffdd9aacff7d2d73e1b691..0bc003c8f8f6b65706436902d33d57b01feb92d9 100644 (file)
--- a/include/babeltrace/ctf/types.h
+++ b/include/babeltrace/ctf/types.h
@@ -92,6 +92,7 @@ struct ctf_stream_pos {
 
        int dummy;              /* dummy position, for length calculation */
        struct bt_stream_callbacks *cb; /* Callbacks registered for iterator. */
+       size_t file_length;     /* length of backing file, in bytes. */
        void *priv;
 };