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Commit	Line	Data
	1	/*
	2	* This file is part of DisOrder
	3	* Copyright (C) 2005, 2006, 2007 Richard Kettlewell
	4	* Portions (C) 2007 Mark Wooding
	5	*
	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.
	10	*
	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.
	15	*
	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/>.
	18	*/
	19	/** @file server/speaker-command.c
	20	* @brief Support for @ref BACKEND_COMMAND */
	21
	22	#include "common.h"
	23
	24	#include <unistd.h>
	25	#include <poll.h>
	26	#include <errno.h>
	27
	28	#include "configuration.h"
	29	#include "syscalls.h"
	30	#include "log.h"
	31	#include "speaker-protocol.h"
	32	#include "speaker.h"
	33
	34	/** @brief Pipe to subprocess
	35	*
	36	* This is the file descriptor to write to for @ref BACKEND_COMMAND.
	37	*/
	38	static int cmdfd = -1;
	39
	40	/** @brief poll array slot for @ref cmdfd
	41	*
	42	* Set by command_beforepoll().
	43	*/
	44	static int cmdfd_slot;
	45
	46	/** @brief Start the subprocess for @ref BACKEND_COMMAND */
	47	static void fork_cmd(void) {
	48	pid_t cmdpid;
	49	int pfd[2];
	50	if(cmdfd != -1) close(cmdfd);
	51	xpipe(pfd);
	52	cmdpid = xfork();
	53	if(!cmdpid) {
	54	exitfn = _exit;
	55	signal(SIGPIPE, SIG_DFL);
	56	xdup2(pfd[0], 0);
	57	close(pfd[0]);
	58	close(pfd[1]);
	59	execl("/bin/sh", "sh", "-c", config->speaker_command, (char *)0);
	60	fatal(errno, "error execing /bin/sh");
	61	}
	62	close(pfd[0]);
	63	cmdfd = pfd[1];
	64	D(("forked cmd %d, fd = %d", cmdpid, cmdfd));
	65	}
	66
	67	/** @brief Command backend initialization */
	68	static void command_init(void) {
	69	info("selected command backend");
	70	fork_cmd();
	71	}
	72
	73	/** @brief Play to a subprocess */
	74	static size_t command_play(size_t frames) {
	75	size_t bytes = frames * bpf;
	76	int written_bytes;
	77
	78	written_bytes = write(cmdfd, playing->buffer + playing->start, bytes);
	79	D(("actually play %zu bytes, wrote %d",
	80	bytes, written_bytes));
	81	if(written_bytes < 0) {
	82	switch(errno) {
	83	case EPIPE:
	84	error(0, "hmm, command died; trying another");
	85	fork_cmd();
	86	return 0;
	87	case EAGAIN:
	88	return 0;
	89	default:
	90	fatal(errno, "error writing to subprocess");
	91	}
	92	} else
	93	return written_bytes / bpf;
	94	}
	95
	96	/** @brief Update poll array for writing to subprocess */
	97	static void command_beforepoll(int attribute((unused)) *timeoutp) {
	98	/* We send sample data to the subprocess as fast as it can accept it.
	99	* This isn't ideal as pause latency can be very high as a result. */
	100	if(cmdfd >= 0)
	101	cmdfd_slot = addfd(cmdfd, POLLOUT);
	102	}
	103
	104	/** @brief Process poll() results for subprocess play */
	105	static int command_ready(void) {
	106	if(fds[cmdfd_slot].revents & (POLLOUT \| POLLERR))
	107	return 1;
	108	else
	109	return 0;
	110	}
	111
	112	const struct speaker_backend command_backend = {
	113	BACKEND_COMMAND,
	114	0,
	115	command_init,
	116	0, /* activate */
	117	command_play,
	118	0, /* deactivate */
	119	command_beforepoll,
	120	command_ready
	121	};
	122
	123	/*
	124	Local Variables:
	125	c-basic-offset:2
	126	comment-column:40
	127	fill-column:79
	128	indent-tabs-mode:nil
	129	End:
	130	*/