[Fix] Try to avoid incomplete writes

diff --git a/src/libserver/maps/map.c b/src/libserver/maps/map.c
index a053ac7ea3c5ca16004b00659a8b89d86a42b852..f365c5901e6249ecbd2f7ba409a6aa2b1ccd26bf 100644 (file)
--- a/src/libserver/maps/map.c
+++ b/src/libserver/maps/map.c
@@ -360,6 +360,7 @@ http_map_finish(struct rspamd_http_connection *conn,
                        cbd->data->last_modified = msg->date;
                }
 
+
                /* Unsigned version - just open file */
                cbd->shmem_data = rspamd_http_message_shmem_ref(msg);
                cbd->data_len = msg->body_buf.len;
@@ -423,12 +424,7 @@ http_map_finish(struct rspamd_http_connection *conn,
 
                MAP_RETAIN(cbd->shmem_data, "shmem_data");
                cbd->data->gen++;
-               /*
-                * We know that a map is in the locked state
-                */
-               g_atomic_int_set(&data->cache->available, 1);
-               g_atomic_int_set(&map->shared->loaded, 1);
-               g_atomic_int_set(&map->shared->cached, 0);
+
                /* Store cached data */
                rspamd_strlcpy(data->cache->shmem_name, cbd->shmem_data->shm_name,
                                           sizeof(data->cache->shmem_name));
@@ -530,6 +526,12 @@ http_map_finish(struct rspamd_http_connection *conn,
 
                cbd->periodic->cur_backend++;
                munmap(in, dlen);
+
+               /* Announce for other processes */
+               g_atomic_int_set(&data->cache->available, 1);
+               g_atomic_int_set(&map->shared->loaded, 1);
+               g_atomic_int_set(&map->shared->cached, 0);
+
                rspamd_map_process_periodic(cbd->periodic);
        }
        else if (msg->code == 304 && cbd->check) {
@@ -1483,7 +1485,7 @@ rspamd_map_save_http_cached_file(struct rspamd_map *map,
                                                                 const unsigned char *data,
                                                                 gsize len)
 {
-       char path[PATH_MAX];
+       char path[PATH_MAX], temp_path[PATH_MAX];
        unsigned char digest[rspamd_cryptobox_HASHBYTES];
        struct rspamd_config *cfg = map->cfg;
        int fd;
@@ -1496,8 +1498,10 @@ rspamd_map_save_http_cached_file(struct rspamd_map *map,
        rspamd_cryptobox_hash(digest, bk->uri, strlen(bk->uri), NULL, 0);
        rspamd_snprintf(path, sizeof(path), "%s%c%*xs.map", cfg->maps_cache_dir,
                                        G_DIR_SEPARATOR, 20, digest);
+       rspamd_snprintf(temp_path, sizeof(temp_path), "%s.tmp.%d.%d", path,
+                                       (int) getpid(), (int) rspamd_get_calendar_ticks());
 
-       fd = rspamd_file_xopen(path, O_WRONLY | O_TRUNC | O_CREAT,
+       fd = rspamd_file_xopen(temp_path, O_WRONLY | O_TRUNC | O_CREAT,
                                                   00600, FALSE);
 
        if (fd == -1) {
@@ -1505,8 +1509,9 @@ rspamd_map_save_http_cached_file(struct rspamd_map *map,
        }
 
        if (!rspamd_file_lock(fd, FALSE)) {
-               msg_err_map("cannot lock file %s: %s", path, strerror(errno));
+               msg_err_map("cannot lock file %s: %s", temp_path, strerror(errno));
                close(fd);
+               unlink(temp_path);
 
                return FALSE;
        }
@@ -1525,9 +1530,10 @@ rspamd_map_save_http_cached_file(struct rspamd_map *map,
        }
 
        if (write(fd, &header, sizeof(header)) != sizeof(header)) {
-               msg_err_map("cannot write file %s (header stage): %s", path, strerror(errno));
+               msg_err_map("cannot write file %s (header stage): %s", temp_path, strerror(errno));
                rspamd_file_unlock(fd, FALSE);
                close(fd);
+               unlink(temp_path);
 
                return FALSE;
        }
@@ -1535,9 +1541,10 @@ rspamd_map_save_http_cached_file(struct rspamd_map *map,
        if (header.etag_len > 0) {
                if (write(fd, RSPAMD_FSTRING_DATA(htdata->etag), header.etag_len) !=
                        header.etag_len) {
-                       msg_err_map("cannot write file %s (etag stage): %s", path, strerror(errno));
+                       msg_err_map("cannot write file %s (etag stage): %s", temp_path, strerror(errno));
                        rspamd_file_unlock(fd, FALSE);
                        close(fd);
+                       unlink(temp_path);
 
                        return FALSE;
                }
@@ -1545,9 +1552,10 @@ rspamd_map_save_http_cached_file(struct rspamd_map *map,
 
        /* Now write the rest */
        if (write(fd, data, len) != len) {
-               msg_err_map("cannot write file %s (data stage): %s", path, strerror(errno));
+               msg_err_map("cannot write file %s (data stage): %s", temp_path, strerror(errno));
                rspamd_file_unlock(fd, FALSE);
                close(fd);
+               unlink(temp_path);
 
                return FALSE;
        }
@@ -1555,6 +1563,13 @@ rspamd_map_save_http_cached_file(struct rspamd_map *map,
        rspamd_file_unlock(fd, FALSE);
        close(fd);
 
+       /* Atomically move temp file to final location */
+       if (rename(temp_path, path) != 0) {
+               msg_err_map("cannot rename %s to %s: %s", temp_path, path, strerror(errno));
+               unlink(temp_path);
+               return FALSE;
+       }
+
        msg_info_map("saved data from %s in %s, %uz bytes", bk->uri, path, len + sizeof(header) + header.etag_len);
 
        return TRUE;