Add mmap trace reading

This set of functions allows a client to open a trace that is not stored
on tracefiles but instead is in memory.
Since the parameters required for such an operation are really different
than typical traces, we define the open_mmap_trace function.
This patch also introduces the mmap_stream structure and
mmap_stream_list that represents a list of FDs readable by mmap.

[ Edit by Mathieu Desnoyers: cleanup ]

Signed-off-by: Julien Desfossez <julien.desfossez@polymtl.ca>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/formats/ctf/ctf.c b/formats/ctf/ctf.c
index 7767c3478ca0e2b005f732e4b858f602d58310f4..0af34aab01412b6c558b0157bf550d30b87b9a59 100644 (file)
--- a/formats/ctf/ctf.c
+++ b/formats/ctf/ctf.c
@@ -59,6 +59,12 @@ struct trace_descriptor *ctf_open_trace(const char *path, int flags,
                void (*move_pos_slow)(struct ctf_stream_pos *pos, size_t offset,
                        int whence), FILE *metadata_fp);
 static
                void (*move_pos_slow)(struct ctf_stream_pos *pos, size_t offset,
                        int whence), FILE *metadata_fp);
 static

+struct trace_descriptor *ctf_open_mmap_trace(
+               struct mmap_stream_list *mmap_list,
+               void (*move_pos_slow)(struct ctf_stream_pos *pos, size_t offset, int whence),
+               FILE *metadata_fp);
+
+static

 void ctf_close_trace(struct trace_descriptor *descriptor);
 
 static
 void ctf_close_trace(struct trace_descriptor *descriptor);
 
 static


@@ -88,6 +94,7 @@ rw_dispatch write_dispatch_table[] = {
 static
 struct format ctf_format = {
        .open_trace = ctf_open_trace,
 static
 struct format ctf_format = {
        .open_trace = ctf_open_trace,

+       .open_mmap_trace = ctf_open_mmap_trace,

        .close_trace = ctf_close_trace,
 };
 
        .close_trace = ctf_close_trace,
 };
 


@@ -1239,6 +1246,153 @@ error:
        return NULL;
 }
 
        return NULL;
 }
 

+
+void ctf_init_mmap_pos(struct ctf_stream_pos *pos,
+               struct mmap_stream *mmap_info)
+{
+       pos->mmap_offset = 0;
+       pos->packet_size = 0;
+       pos->content_size = 0;
+       pos->content_size_loc = NULL;
+       pos->fd = mmap_info->fd;
+       pos->base = 0;
+       pos->offset = 0;
+       pos->dummy = false;
+       pos->cur_index = 0;
+       pos->packet_index = NULL;
+       pos->prot = PROT_READ;
+       pos->flags = MAP_PRIVATE;
+       pos->parent.rw_table = read_dispatch_table;
+       pos->parent.event_cb = ctf_read_event;
+}
+
+static
+int prepare_mmap_stream_definition(struct ctf_trace *td,
+               struct ctf_file_stream *file_stream)
+{
+       struct ctf_stream_class *stream;
+       uint64_t stream_id = 0;
+       int ret;
+
+       file_stream->parent.stream_id = stream_id;
+       if (stream_id >= td->streams->len) {
+               fprintf(stdout, "[error] Stream %" PRIu64 " is not declared "
+                               "in metadata.\n", stream_id);
+               ret = -EINVAL;
+               goto end;
+       }
+       stream = g_ptr_array_index(td->streams, stream_id);
+       if (!stream) {
+               fprintf(stdout, "[error] Stream %" PRIu64 " is not declared "
+                               "in metadata.\n", stream_id);
+               ret = -EINVAL;
+               goto end;
+       }
+       file_stream->parent.stream_class = stream;
+       ret = create_stream_definitions(td, &file_stream->parent);
+end:
+       return ret;
+}
+
+static
+int ctf_open_mmap_stream_read(struct ctf_trace *td,
+               struct mmap_stream *mmap_info,
+               void (*move_pos_slow)(struct ctf_stream_pos *pos, size_t offset,
+                       int whence))
+{
+       int ret;
+       struct ctf_file_stream *file_stream;
+
+       file_stream = g_new0(struct ctf_file_stream, 1);
+       ctf_init_mmap_pos(&file_stream->pos, mmap_info);
+
+       file_stream->pos.move_pos_slow = move_pos_slow;
+
+       ret = create_trace_definitions(td, &file_stream->parent);
+       if (ret) {
+               goto error_def;
+       }
+
+       ret = prepare_mmap_stream_definition(td, file_stream);
+       if (ret)
+               goto error_index;
+
+       /* Add stream file to stream class */
+       g_ptr_array_add(file_stream->parent.stream_class->streams,
+                       &file_stream->parent);
+       return 0;
+
+error_index:
+       if (file_stream->parent.trace_packet_header)
+               definition_unref(&file_stream->parent.trace_packet_header->p);
+error_def:
+       g_free(file_stream);
+       return ret;
+}
+
+int ctf_open_mmap_trace_read(struct ctf_trace *td,
+               struct mmap_stream_list *mmap_list,
+               void (*move_pos_slow)(struct ctf_stream_pos *pos, size_t offset,
+                       int whence),
+               FILE *metadata_fp)
+{
+       int ret;
+       struct mmap_stream *mmap_info;
+
+       ret = ctf_open_trace_metadata_read(td, ctf_move_pos_slow, metadata_fp);
+       if (ret) {
+               goto error;
+       }
+
+       /*
+        * for each stream, try to open, check magic number, and get the
+        * stream ID to add to the right location in the stream array.
+        */
+       cds_list_for_each_entry(mmap_info, &mmap_list->head, list) {
+               ret = ctf_open_mmap_stream_read(td, mmap_info, move_pos_slow);
+               if (ret) {
+                       fprintf(stdout, "[error] Open file mmap stream error.\n");
+                       goto error;
+               }
+       }
+
+       return 0;
+
+error:
+       return ret;
+}
+
+static
+struct trace_descriptor *ctf_open_mmap_trace(
+               struct mmap_stream_list *mmap_list,
+               void (*move_pos_slow)(struct ctf_stream_pos *pos, size_t offset, int whence),
+               FILE *metadata_fp)
+{
+       struct ctf_trace *td;
+       int ret;
+
+       if (!metadata_fp) {
+               fprintf(stderr, "[error] No metadata file pointer associated, "
+                               "required for mmap parsing\n");
+               goto error;
+       }
+       if (!move_pos_slow) {
+               fprintf(stderr, "[error] move_pos_slow function undefined.\n");
+               goto error;
+       }
+       td = g_new0(struct ctf_trace, 1);
+       ret = ctf_open_mmap_trace_read(td, mmap_list, move_pos_slow, metadata_fp);
+       if (ret)
+               goto error_free;
+
+       return &td->parent;
+
+error_free:
+       g_free(td);
+error:
+       return NULL;
+}
+

 static
 void ctf_close_file_stream(struct ctf_file_stream *file_stream)
 {
 static
 void ctf_close_file_stream(struct ctf_file_stream *file_stream)
 {

diff --git a/include/babeltrace/format.h b/include/babeltrace/format.h
index 5b2f694573b65caf00df81ba17a3f4ad912d6999..5cf795a76418f5f281b826a5f33b455e001dec93 100644 (file)
--- a/include/babeltrace/format.h
+++ b/include/babeltrace/format.h
@@ -31,12 +31,25 @@
 struct trace_descriptor {
 };
 
 struct trace_descriptor {
 };
 

+struct mmap_stream {
+       int fd;
+       struct cds_list_head list;
+};
+
+struct mmap_stream_list {
+       struct cds_list_head head;
+};
+

 struct format {
        GQuark name;
 
        struct trace_descriptor *(*open_trace)(const char *path, int flags,
                        void (*move_pos_slow)(struct ctf_stream_pos *pos, size_t offset,
                                int whence), FILE *metadata_fp);
 struct format {
        GQuark name;
 
        struct trace_descriptor *(*open_trace)(const char *path, int flags,
                        void (*move_pos_slow)(struct ctf_stream_pos *pos, size_t offset,
                                int whence), FILE *metadata_fp);

+       struct trace_descriptor *(*open_mmap_trace)(
+                       struct mmap_stream_list *mmap_list,
+                       void (*move_pos_slow)(struct ctf_stream_pos *pos, size_t offset,
+                               int whence), FILE *metadata_fp);

        void (*close_trace)(struct trace_descriptor *descriptor);
 };
 
        void (*close_trace)(struct trace_descriptor *descriptor);
 };