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livetrax/libs/ardouralsautil/request_device.c

140 lines
4.0 KiB
C

/*
* Copyright (C) 2014 Robin Gareus <robin@gareus.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include "ardouralsautil/reserve.h"
static int run = 1;
static void wearedone(int sig) {
(void) sig; // skip 'unused variable' compiler warning;
fprintf(stderr, "caught signal - shutting down.\n");
run=0;
}
static int stdin_available(void) {
errno = 0;
if (fcntl(STDIN_FILENO, F_GETFD) == 1) return 0;
return errno != EBADF;
}
static void usage(int status) {
printf ("ardour-request-device - DBus Audio Reservation Utility.\n");
printf ("Usage: ardour-request-device [ OPTIONS ] <Audio-Device-ID>\n");
printf ("Options:\n\
-h, --help display this help and exit\n\
-V, --version print version information and exit\n\
");
printf ("\n\
This tool issues a dbus request to reserve an ALSA Audio-device.\n\
If successful other users of the device (e.g. pulseaudio) will\n\
release the device so that ardour can access it.\n\
\n\
ardour-request-device announces itself as \"Ardour ALSA Backend\" and uses the\n\
maximum possible priority for requesting the device.\n\
\n\
The audio-device-id is a string e.g. 'Audio1'\n\
\n\
Examples:\n\
ardour-request-device Audio0\n\
\n");
printf ("Report bugs to Robin Gareus <robin@gareus.org>\n");
exit (status);
}
static void print_version(void) {
printf ("ardour-request-device 0.1\n\n");
printf (
"Copyright (C) 2014 Robin Gareus <robin@gareus.org>\n"
"This is free software; see the source for copying conditions. There is NO\n"
"warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\n"
);
exit (0);
}
int main(int argc, char **argv) {
DBusConnection* dbus_connection = NULL;
rd_device * reserved_device = NULL;
DBusError error;
int ret;
if (argc < 2 || argc > 2) {
usage(EXIT_FAILURE);
}
if (!strcmp(argv[1], "-V") || !strcmp(argv[1], "--version")) {
print_version();
}
if (!strcmp(argv[1], "-h") || !strcmp(argv[1], "--help")) {
usage(EXIT_SUCCESS);
}
const char *device_name = argv[1];
dbus_error_init(&error);
if (!(dbus_connection = dbus_bus_get (DBUS_BUS_SESSION, &error))) {
fprintf(stderr, "Failed to connect to session bus for device reservation: %s\n", error.message ? error.message : "unknown error.");
dbus_error_free(&error);
return EXIT_FAILURE;
}
if ((ret = rd_acquire (
&reserved_device,
dbus_connection,
device_name,
"Ardour ALSA Backend",
INT32_MAX,
NULL,
&error)) < 0)
{
fprintf(stderr, "Failed to acquire device: '%s'\n%s\n", device_name, (error.message ? error.message : strerror(-ret)));
dbus_error_free(&error);
dbus_connection_unref(dbus_connection);
return EXIT_FAILURE;
}
fprintf(stdout, "Acquired audio-card '%s'\n", device_name);
fprintf(stdout, "Press Ctrl+C or close stdin to release the device.\n");
fflush(stdout);
signal(SIGTERM, wearedone);
signal(SIGINT, wearedone);
while (run && dbus_connection_read_write_dispatch (dbus_connection, 200)) {
if (!stdin_available()) {
fprintf(stderr, "stdin closed - shutting down.\n");
break;
}
}
rd_release (reserved_device);
fprintf(stdout, "Released audio-card '%s'\n", device_name);
dbus_error_free(&error);
dbus_connection_unref(dbus_connection);
return EXIT_SUCCESS;
}