2 * This file is part of DisOrder.
3 * Copyright (C) 2005, 2006, 2007, 2009 Richard Kettlewell
4 * Portions (C) 2007 Mark Wooding
6 * This program is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
19 /** @file lib/uaudio-command.c
20 * @brief Support for commmand backend
22 * We use the code in @ref lib/uaudio-schedule.c to ensure that we write at
23 * approximately the 'real' rate. For disorder-playrtp this isn't very useful
24 * (thought it might reduce the size of various buffers downstream of us) but
25 * when run from the speaker it means that pausing stands a chance of working.
37 #include "configuration.h"
39 /** @brief Pipe to subprocess */
40 static int command_fd;
42 /** @brief Child process ID */
43 static pid_t command_pid;
45 static const char *const command_options[] = {
50 /** @brief Close pipe and wait for subprocess to terminate */
51 static void command_wait(void) {
57 while((rc = waitpid(command_pid, &w, 0) < 0 && errno == EINTR))
60 fatal(errno, "waitpid");
63 error(0, "command subprocess %s", ws);
68 /** @brief Create subprocess */
69 static void command_open(void) {
73 if(!(command = uaudio_get("command", NULL)))
74 fatal(0, "'command' not set");
76 command_pid = xfork();
79 signal(SIGPIPE, SIG_DFL);
83 /* TODO it would be nice to set some environment variables given the sample
84 * format. The original intended model is that you adapt DisOrder to the
85 * command you run but it'd be nice to support the opposite. */
86 execl("/bin/sh", "sh", "-c", command, (char *)0);
87 fatal(errno, "error executing /bin/sh");
93 /** @brief Send audio data to subprocess */
94 static size_t command_play(void *buffer, size_t nsamples) {
95 uaudio_schedule_synchronize();
96 const size_t bytes = nsamples * uaudio_sample_size;
97 int written = write(command_fd, buffer, bytes);
101 return 0; /* will retry */
103 error(0, "audio command subprocess terminated");
106 return 0; /* will retry */
108 fatal(errno, "error writing to audio command subprocess");
111 const size_t written_samples = written / uaudio_sample_size;
112 uaudio_schedule_update(written_samples);
113 return written_samples;
116 static void command_start(uaudio_callback *callback,
119 uaudio_schedule_init();
120 uaudio_thread_start(callback,
124 4096 / uaudio_sample_size);
127 static void command_stop(void) {
128 uaudio_thread_stop();
132 static void command_activate(void) {
133 uaudio_schedule_reactivated = 1;
134 uaudio_thread_activate();
137 static void command_deactivate(void) {
138 uaudio_thread_deactivate();
141 static void command_configure(void) {
142 uaudio_set("command", config->speaker_command);
145 const struct uaudio uaudio_command = {
147 .options = command_options,
148 .start = command_start,
149 .stop = command_stop,
150 .activate = command_activate,
151 .deactivate = command_deactivate,
152 .configure = command_configure,