common: trace-chunk: track all files within a chunk

Track all files added/removed in a chunk. Required by the clear
feature so all files of a prior chunk can be unlinked, even if
they belong to applications which have already closed their
stream with per-pid UST buffers.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I41bf8ac61f9a8ed1e8f206520ef8845a102b1c1e
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

diff --git a/src/common/trace-chunk.c b/src/common/trace-chunk.c
index bba90f1ac6b8026e1886aef4fbf28a3c1426f9a4..8a450c547017ac3dd85bac29fde8a893db229d40 100644 (file)
--- a/src/common/trace-chunk.c
+++ b/src/common/trace-chunk.c
@@ -78,6 +78,11 @@ struct lttng_trace_chunk {
         * Only used by _owner_ mode chunks.
         */
        struct lttng_dynamic_pointer_array top_level_directories;
+       /*
+        * All files contained within the trace chunk.
+        * Array of paths (char *).
+        */
+       struct lttng_dynamic_pointer_array files;
        /* Is contained within an lttng_trace_chunk_registry_element? */
        bool in_registry_element;
        bool name_overridden;
@@ -220,6 +225,7 @@ void lttng_trace_chunk_init(struct lttng_trace_chunk *chunk)
        urcu_ref_init(&chunk->ref);
        pthread_mutex_init(&chunk->lock, NULL);
        lttng_dynamic_pointer_array_init(&chunk->top_level_directories, free);
+       lttng_dynamic_pointer_array_init(&chunk->files, free);
 }
 
 static
@@ -237,6 +243,7 @@ void lttng_trace_chunk_fini(struct lttng_trace_chunk *chunk)
        free(chunk->name);
        chunk->name = NULL;
        lttng_dynamic_pointer_array_reset(&chunk->top_level_directories);
+       lttng_dynamic_pointer_array_reset(&chunk->files);
        pthread_mutex_destroy(&chunk->lock);
 }
 
@@ -817,6 +824,80 @@ end:
        return status;
 }
 
+/*
+ * TODO: Implement O(1) lookup.
+ */
+static
+bool lttng_trace_chunk_find_file(struct lttng_trace_chunk *chunk,
+               const char *path, size_t *index)
+{
+       size_t i, count;
+
+       count = lttng_dynamic_pointer_array_get_count(&chunk->files);
+       for (i = 0; i < count; i++) {
+               const char *iter_path =
+                               lttng_dynamic_pointer_array_get_pointer(
+                                       &chunk->files, i);
+               if (!strcmp(iter_path, path)) {
+                       if (index) {
+                               *index = i;
+                       }
+                       return true;
+               }
+       }
+       return false;
+}
+
+static
+enum lttng_trace_chunk_status lttng_trace_chunk_add_file(
+               struct lttng_trace_chunk *chunk,
+               const char *path)
+{
+       char *copy;
+       int ret;
+       enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
+
+       if (lttng_trace_chunk_find_file(chunk, path, NULL)) {
+               return LTTNG_TRACE_CHUNK_STATUS_OK;
+       }
+       DBG("Adding new file \"%s\" to trace chunk \"%s\"",
+                       path, chunk->name ? : "(unnamed)");
+       copy = strdup(path);
+       if (!copy) {
+               PERROR("Failed to copy path");
+               status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
+               goto end;
+       }
+       ret = lttng_dynamic_pointer_array_add_pointer(
+                       &chunk->files, copy);
+       if (ret) {
+               ERR("Allocation failure while adding file to a trace chunk");
+               free(copy);
+               status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
+               goto end;
+       }
+end:
+       return status;
+}
+
+static
+void lttng_trace_chunk_remove_file(
+               struct lttng_trace_chunk *chunk,
+               const char *path)
+{
+       size_t index;
+       bool found;
+       int ret;
+
+       found = lttng_trace_chunk_find_file(chunk, path, &index);
+       if (!found) {
+               return;
+       }
+       ret = lttng_dynamic_pointer_array_remove_pointer(
+                       &chunk->files, index);
+       assert(!ret);
+}
+
 LTTNG_HIDDEN
 enum lttng_trace_chunk_status lttng_trace_chunk_open_file(
                struct lttng_trace_chunk *chunk, const char *file_path,
@@ -843,6 +924,10 @@ enum lttng_trace_chunk_status lttng_trace_chunk_open_file(
                status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
                goto end;
        }
+       status = lttng_trace_chunk_add_file(chunk, file_path);
+       if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
+               goto end;
+       }
        ret = lttng_directory_handle_open_file_as_user(
                        chunk->chunk_directory, file_path, flags, mode,
                        chunk->credentials.value.use_current_user ?
@@ -855,6 +940,7 @@ enum lttng_trace_chunk_status lttng_trace_chunk_open_file(
                                file_path, flags, (int) mode);
                        status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
                }
+               lttng_trace_chunk_remove_file(chunk, file_path);
                goto end;
        }
        *out_fd = ret;
@@ -896,6 +982,7 @@ int lttng_trace_chunk_unlink_file(struct lttng_trace_chunk *chunk,
                status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
                goto end;
        }
+       lttng_trace_chunk_remove_file(chunk, file_path);
 end:
        pthread_mutex_unlock(&chunk->lock);
        return status;