+ void *query_shm;
+ struct callback_query *cq;
+ int ret, ret2;
+ struct afs_callback_arg aca = {.fd = fd};
+
+ ret = shm_attach(query_shmid, ATTACH_RW, &query_shm);
+ if (ret < 0)
+ return ret;
+ cq = query_shm;
+ aca.query.data = (char *)query_shm + sizeof(*cq);
+ aca.query.size = cq->query_size;
+ aca.pbout.max_size = shm_get_shmmax();
+ aca.pbout.max_size_handler = afs_max_size_handler;
+ aca.pbout.private_data = &(struct afs_max_size_handler_data) {
+ .fd = fd,
+ .band = SBD_OUTPUT
+ };
+ ret = cq->handler(&aca);
+ ret2 = shm_detach(query_shm);
+ if (ret2 < 0) {
+ if (ret < 0) /* ignore (but log) detach error */
+ PARA_ERROR_LOG("could not detach sma: %s\n",
+ para_strerror(-ret2));
+ else
+ ret = ret2;
+ }
+ flush_and_free_pb(&aca.pbout);
+ if (ret < 0) {
+ ret2 = pass_buffer_as_shm(fd, SBD_AFS_CB_FAILURE,
+ (const char *)&ret, sizeof(ret));
+ if (ret2 < 0)
+ PARA_ERROR_LOG("could not pass cb failure packet: %s\n",
+ para_strerror(-ret));
+ }
+ return ret;
+}
+
+static int execute_server_command(fd_set *rfds)
+{
+ char buf[8];
+ size_t n;
+ int ret = read_nonblock(server_socket, buf, sizeof(buf) - 1, rfds, &n);
+
+ if (ret < 0 || n == 0)
+ return ret;
+ buf[n] = '\0';
+ if (strcmp(buf, "new"))
+ return -E_BAD_CMD;
+ return open_next_audio_file();
+}
+
+/* returns 0 if no data available, 1 else */
+static int execute_afs_command(int fd, fd_set *rfds, uint32_t expected_cookie)
+{
+ uint32_t cookie;
+ int query_shmid;
+ char buf[sizeof(cookie) + sizeof(query_shmid)];
+ size_t n;
+ int ret = read_nonblock(fd, buf, sizeof(buf), rfds, &n);
+
+ if (ret < 0)
+ goto err;
+ if (n == 0)
+ return 0;
+ if (n != sizeof(buf)) {
+ PARA_NOTICE_LOG("short read (%d bytes, expected %lu)\n",
+ ret, (long unsigned) sizeof(buf));
+ return 1;
+ }
+ cookie = *(uint32_t *)buf;
+ if (cookie != expected_cookie) {
+ PARA_NOTICE_LOG("received invalid cookie (got %u, expected %u)\n",
+ (unsigned)cookie, (unsigned)expected_cookie);
+ return 1;
+ }
+ query_shmid = *(int *)(buf + sizeof(cookie));
+ if (query_shmid < 0) {
+ PARA_WARNING_LOG("received invalid query shmid %d)\n",
+ query_shmid);
+ return 1;
+ }
+ ret = call_callback(fd, query_shmid);
+ if (ret >= 0)
+ return 1;
+err:
+ PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
+ return 1;
+}
+
+/** Shutdown connection if query has not arrived until this many seconds. */
+#define AFS_CLIENT_TIMEOUT 3
+
+static int command_post_select(struct sched *s, void *context)
+{
+ struct command_task *ct = context;
+ struct sockaddr_un unix_addr;
+ struct afs_client *client, *tmp;
+ int fd, ret;
+
+ ret = task_get_notification(ct->task);
+ if (ret < 0)
+ return ret;
+ ret = execute_server_command(&s->rfds);
+ if (ret < 0) {
+ PARA_EMERG_LOG("%s\n", para_strerror(-ret));
+ task_notify_all(s, -ret);
+ return ret;
+ }
+ /* Check the list of connected clients. */
+ list_for_each_entry_safe(client, tmp, &afs_client_list, node) {
+ ret = execute_afs_command(client->fd, &s->rfds, ct->cookie);
+ if (ret == 0) { /* prevent bogus connection flooding */
+ struct timeval diff;
+ tv_diff(now, &client->connect_time, &diff);
+ if (diff.tv_sec < AFS_CLIENT_TIMEOUT)
+ continue;
+ PARA_WARNING_LOG("connection timeout\n");
+ }
+ close(client->fd);
+ list_del(&client->node);
+ free(client);
+ }
+ /* Accept connections on the local socket. */
+ ret = para_accept(ct->fd, &s->rfds, &unix_addr, sizeof(unix_addr), &fd);
+ if (ret < 0)
+ PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
+ if (ret <= 0)
+ return 0;
+ ret = mark_fd_nonblocking(fd);
+ if (ret < 0) {
+ PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
+ close(fd);
+ return 0;
+ }
+ client = para_malloc(sizeof(*client));
+ client->fd = fd;
+ client->connect_time = *now;
+ para_list_add(&client->node, &afs_client_list);
+ return 0;
+}
+
+static void register_command_task(uint32_t cookie, struct sched *s)
+{
+ struct command_task *ct = &command_task_struct;
+ ct->fd = setup_command_socket_or_die();
+ ct->cookie = cookie;
+
+ ct->task = task_register(&(struct task_info) {
+ .name = "afs command",
+ .pre_select = command_pre_select,
+ .post_select = command_post_select,
+ .context = ct,
+ }, s);