+int pass_buffer_as_shm(int fd, uint8_t band, const char *buf, size_t size)
+{
+ int ret, shmid;
+ void *shm;
+ struct callback_result *cr;
+
+ if (size == 0)
+ assert(band != SBD_OUTPUT);
+ ret = shm_new(size + sizeof(*cr));
+ if (ret < 0)
+ return ret;
+ shmid = ret;
+ ret = shm_attach(shmid, ATTACH_RW, &shm);
+ if (ret < 0)
+ goto err;
+ cr = shm;
+ cr->result_size = size;
+ cr->band = band;
+ if (size > 0)
+ memcpy(shm + sizeof(*cr), buf, size);
+ ret = shm_detach(shm);
+ if (ret < 0)
+ goto err;
+ ret = write_all(fd, (char *)&shmid, sizeof(int));
+ if (ret >= 0)
+ return ret;
+err:
+ if (shm_destroy(shmid) < 0)
+ PARA_ERROR_LOG("destroy result failed\n");
+ return ret;
+}
+
+static int call_callback(int fd, int query_shmid)
+{
+ 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 -ERRNO_TO_PARA_ERROR(EINVAL);
+ 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)