Fix: use memstream instead of tmp file for live metadata

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

diff --git a/formats/lttng-live/lttng-live-comm.c b/formats/lttng-live/lttng-live-comm.c
index 0cf38e6e0437abc39cd12ca7a5ee4a7c2a8a7ea9..7076f9c5edb723972f69ddeadfd66e2ecdabb1cb 100644 (file)
--- a/formats/lttng-live/lttng-live-comm.c
+++ b/formats/lttng-live/lttng-live-comm.c
@@ -49,6 +49,8 @@
 #include <babeltrace/ctf/events-internal.h>
 #include <formats/ctf/events-private.h>
 
+#include <babeltrace/compat/memstream.h>
+
 #include "lttng-live.h"
 #include "lttng-viewer-abi.h"
 
@@ -67,7 +69,8 @@ static void ctf_live_packet_seek(struct bt_stream_pos *stream_pos,
 static void add_traces(gpointer key, gpointer value, gpointer user_data);
 static int del_traces(gpointer key, gpointer value, gpointer user_data);
 static int get_new_metadata(struct lttng_live_ctx *ctx,
-               struct lttng_live_viewer_stream *viewer_stream);
+               struct lttng_live_viewer_stream *viewer_stream,
+               char **metadata_buf);
 
 int lttng_live_connect_viewer(struct lttng_live_ctx *ctx)
 {
@@ -348,6 +351,22 @@ int lttng_live_ctf_trace_assign(struct lttng_live_viewer_stream *stream,
        return ret;
 }
 
+static
+int open_metadata_fp_write(struct lttng_live_viewer_stream *stream,
+               char **metadata_buf, size_t *size)
+{
+       int ret = 0;
+
+       stream->metadata_fp_write =
+               babeltrace_open_memstream(metadata_buf, size);
+       if (!stream->metadata_fp_write) {
+               perror("Metadata open_memstream");
+               ret = -1;
+       }
+
+       return ret;
+}
+
 int lttng_live_attach_session(struct lttng_live_ctx *ctx, uint64_t id)
 {
        struct lttng_viewer_cmd cmd;
@@ -473,35 +492,7 @@ int lttng_live_attach_session(struct lttng_live_ctx *ctx, uint64_t id)
                ctx->session->streams[i].mmap_size = 0;
 
                if (be32toh(stream.metadata_flag)) {
-                       char *path;
-
-                       path = strdup(LTTNG_METADATA_PATH_TEMPLATE);
-                       if (!path) {
-                               perror("strdup");
-                               ret = -1;
-                               goto error;
-                       }
-                       if (!mkdtemp(path)) {
-                               perror("mkdtemp");
-                               free(path);
-                               ret = -1;
-                               goto error;
-                       }
                        ctx->session->streams[i].metadata_flag = 1;
-                       snprintf(ctx->session->streams[i].path,
-                                       sizeof(ctx->session->streams[i].path),
-                                       "%s/%s", path,
-                                       stream.channel_name);
-                       ret = open(ctx->session->streams[i].path,
-                                       O_WRONLY | O_CREAT | O_TRUNC,
-                                       S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
-                       if (ret < 0) {
-                               perror("open");
-                               free(path);
-                               goto error;
-                       }
-                       ctx->session->streams[i].fd = ret;
-                       free(path);
                }
                ret = lttng_live_ctf_trace_assign(&ctx->session->streams[i],
                                be64toh(stream.ctf_trace_id));
@@ -813,14 +804,17 @@ int get_one_metadata_packet(struct lttng_live_ctx *ctx,
        assert(ret_len == len);
 
        do {
-               ret_len = write(metadata_stream->fd, data, len);
+               ret_len = fwrite(data, 1, len,
+                               metadata_stream->metadata_fp_write);
        } while (ret_len < 0 && errno == EINTR);
        if (ret_len < 0) {
+               fprintf(stderr, "[error] Writing in the metadata fp\n");
                free(data);
                ret = ret_len;
                goto error;
        }
        assert(ret_len == len);
+       metadata_stream->metadata_len += len;
        ret = len;
 
        free(data);
@@ -835,12 +829,19 @@ error:
  */
 static
 int get_new_metadata(struct lttng_live_ctx *ctx,
-               struct lttng_live_viewer_stream *viewer_stream)
+               struct lttng_live_viewer_stream *viewer_stream,
+               char **metadata_buf)
 {
        int ret = 0;
        struct lttng_live_viewer_stream *metadata_stream;
+       size_t size;
 
        metadata_stream = viewer_stream->ctf_trace->metadata_stream;
+       metadata_stream->metadata_len = 0;
+       ret = open_metadata_fp_write(metadata_stream, metadata_buf, &size);
+       if (ret < 0) {
+               goto error;
+       }
 
        do {
                /*
@@ -851,6 +852,10 @@ int get_new_metadata(struct lttng_live_ctx *ctx,
                ret = get_one_metadata_packet(ctx, metadata_stream);
        } while (ret > 0);
 
+       fclose(metadata_stream->metadata_fp_write);
+       metadata_stream->metadata_fp_write = NULL;
+
+error:
        return ret;
 }
 
@@ -932,11 +937,23 @@ retry:
                index->events_discarded = be64toh(rp.events_discarded);
 
                if (rp.flags & LTTNG_VIEWER_FLAG_NEW_METADATA) {
+                       struct lttng_live_viewer_stream *metadata;
+                       char *metadata_buf = NULL;
+
                        printf_verbose("get_next_index: new metadata needed\n");
-                       ret = get_new_metadata(ctx, viewer_stream);
+                       ret = get_new_metadata(ctx, viewer_stream, &metadata_buf);
                        if (ret < 0) {
                                goto error;
                        }
+                       metadata = viewer_stream->ctf_trace->metadata_stream;
+                       metadata->ctf_trace->metadata_fp =
+                               babeltrace_fmemopen(metadata_buf,
+                                       metadata->metadata_len, "rb");
+                       if (!metadata->ctf_trace->metadata_fp) {
+                               perror("Metadata fmemopen");
+                               ret = -1;
+                               goto error;
+                       }
                }
                if (rp.flags & LTTNG_VIEWER_FLAG_NEW_STREAM) {
                        ret = ask_new_streams(ctx);
@@ -953,7 +970,6 @@ retry:
        case LTTNG_VIEWER_INDEX_HUP:
                printf_verbose("get_next_index: stream hung up\n");
                viewer_stream->id = -1ULL;
-               viewer_stream->fd = -1;
                index->offset = EOF;
                ctx->session->stream_count--;
                break;
@@ -1206,11 +1222,29 @@ void add_traces(gpointer key, gpointer value, gpointer user_data)
                        new_mmap_stream->fd = -1;
                        bt_list_add(&new_mmap_stream->list, &mmap_list.head);
                } else {
+                       char *metadata_buf = NULL;
+
                        /* Get all possible metadata before starting */
-                       ret = get_new_metadata(ctx, stream);
-                       if (ret)
+                       ret = get_new_metadata(ctx, stream, &metadata_buf);
+                       if (ret) {
+                               free(metadata_buf);
+                               goto end_free;
+                       }
+                       if (!stream->metadata_len) {
+                               fprintf(stderr, "[error] empty metadata\n");
+                               ret = -1;
+                               free(metadata_buf);
+                               goto end_free;
+                       }
+
+                       trace->metadata_fp = babeltrace_fmemopen(metadata_buf,
+                                       stream->metadata_len, "rb");
+                       if (!trace->metadata_fp) {
+                               perror("Metadata fmemopen");
+                               ret = -1;
+                               free(metadata_buf);
                                goto end_free;
-                       trace->metadata_fp = fopen(stream->path, "r");
+                       }
                }
        }
 
@@ -1225,6 +1259,8 @@ void add_traces(gpointer key, gpointer value, gpointer user_data)
                fprintf(stderr, "[error] Error adding trace\n");
                goto end_free;
        }
+       trace->metadata_stream->metadata_len = 0;
+
        handle = (struct bt_trace_handle *) g_hash_table_lookup(
                        bt_ctx->trace_handles,
                        (gpointer) (unsigned long) ret);
@@ -1360,35 +1396,7 @@ int lttng_live_get_new_streams(struct lttng_live_ctx *ctx, uint64_t id)
                ctx->session->streams[i].mmap_size = 0;
 
                if (be32toh(stream.metadata_flag)) {
-                       char *path;
-
-                       path = strdup(LTTNG_METADATA_PATH_TEMPLATE);
-                       if (!path) {
-                               perror("strdup");
-                               ret = -1;
-                               goto error;
-                       }
-                       if (!mkdtemp(path)) {
-                               perror("mkdtemp");
-                               free(path);
-                               ret = -1;
-                               goto error;
-                       }
                        ctx->session->streams[i].metadata_flag = 1;
-                       snprintf(ctx->session->streams[i].path,
-                                       sizeof(ctx->session->streams[i].path),
-                                       "%s/%s", path,
-                                       stream.channel_name);
-                       ret = open(ctx->session->streams[i].path,
-                                       O_WRONLY | O_CREAT | O_TRUNC,
-                                       S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
-                       if (ret < 0) {
-                               perror("open");
-                               free(path);
-                               goto error;
-                       }
-                       ctx->session->streams[i].fd = ret;
-                       free(path);
                }
                ret = lttng_live_ctf_trace_assign(&ctx->session->streams[i],
                                be64toh(stream.ctf_trace_id));

diff --git a/formats/lttng-live/lttng-live.h b/formats/lttng-live/lttng-live.h
index 071f288183564e95ceb69346d094e490952a1a02..09de20b92e1431bb92830bdded8aa9929ce36604 100644 (file)
--- a/formats/lttng-live/lttng-live.h
+++ b/formats/lttng-live/lttng-live.h
@@ -26,7 +26,6 @@
 
 #include <stdint.h>
 
-#define LTTNG_METADATA_PATH_TEMPLATE           "/tmp/lttng-live-XXXXXX"
 #define LTTNG_DEFAULT_NETWORK_VIEWER_PORT      5344
 
 #define LTTNG_LIVE_MAJOR                       2
@@ -46,7 +45,8 @@ struct lttng_live_ctx {
 struct lttng_live_viewer_stream {
        uint64_t id;
        uint64_t mmap_size;
-       int fd;
+       FILE *metadata_fp_write;
+       ssize_t metadata_len;
        int metadata_flag;
        int first_read;
        struct lttng_live_session *session;