258 lines
7.3 KiB
C
258 lines
7.3 KiB
C
/*
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* Copyright (C) 2014 Robin Gareus <robin@gareus.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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// NB generate man-page with
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// help2man -N -n "alsa/ardour dbus device request tool" -o ardour-request-device.1 ./build/libs/ardouralsautil/ardour-request-device
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <getopt.h>
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#include <signal.h>
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#include <string.h>
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#include <fcntl.h>
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#include <errno.h>
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#include "ardouralsautil/reserve.h"
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#ifndef ARD_PROG_NAME
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#define ARD_PROG_NAME "alsa_request_device"
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#endif
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#ifndef ARD_APPL_NAME
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#define ARD_APPL_NAME "ALSA User"
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#endif
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#ifndef VERSION
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#define VERSION "v0.3"
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#endif
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static int run = 1;
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static int release_wait_for_signal = 0;
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static pid_t parent_pid = 0;
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static void wearedone(int sig) {
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(void) sig; // skip 'unused variable' compiler warning;
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fprintf(stderr, "caught signal - shutting down.\n");
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run=0;
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}
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static int stdin_available(void) {
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errno = 0;
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if (fcntl(STDIN_FILENO, F_GETFD) == 1) return 0;
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return errno != EBADF;
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}
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static void print_version () {
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printf (ARD_PROG_NAME " " VERSION "\n\n");
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printf (
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"Copyright (C) 2014 Robin Gareus <robin@gareus.org>\n"
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"This is free software; see the source for copying conditions. There is NO\n"
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"warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\n"
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);
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exit (EXIT_SUCCESS);
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}
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static void usage () {
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printf (ARD_PROG_NAME " - DBus Audio Reservation Utility.\n");
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printf ("Usage: " ARD_PROG_NAME " [ OPTIONS ] <Audio-Device-ID>\n");
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printf ("Options:\n\
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-h, --help display this help and exit\n\
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-p, --priority <int> reservation priority (default: int32_max)\n\
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-P, --pid <int> process-id to watch (default 0: none)\n\
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-n, --name <string> application name to use for registration\n\
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-V, --version print version information and exit\n\
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-w, --releasewait wait for signal on yield-release\n\
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");
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printf ("\n\
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This tool issues a dbus request to reserve an ALSA Audio-device.\n\
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If successful other users of the device (e.g. pulseaudio) will\n\
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release the device.\n\
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\n\
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" ARD_PROG_NAME " by default announces itself as \"" ARD_APPL_NAME "\"\n\
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and uses the maximum possible priority for requesting the device.\n\
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These settings can be overridden using the -n and -p options respectively.\n\
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\n\
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If a PID is given the tool will watch the process and if that is not running\n\
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release the device and exit. Otherwise " ARD_PROG_NAME " runs until\n\
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either stdin is closed, a SIGINT or SIGTERM is received or some other\n\
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application requests the device with a higher priority.\n\
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\n\
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Without the -w option, " ARD_PROG_NAME " yields the device after 500ms to\n\
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any higher-priority request. With the -w option this tool waits until it\n\
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for SIGINT or SIGTERM - but at most 4 sec to acknowledge before releasing.\n\
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\n\
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The audio-device-id is a string e.g. 'Audio1'\n\
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\n\
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Examples:\n\
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" ARD_PROG_NAME " Audio0\n\
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\n");
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printf ("Report bugs to Robin Gareus <robin@gareus.org>\n");
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exit (EXIT_SUCCESS);
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}
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static struct option const long_options[] =
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{
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{"help", no_argument, 0, 'h'},
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{"name", required_argument, 0, 'n'},
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{"pid", required_argument, 0, 'P'},
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{"priority", required_argument, 0, 'p'},
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{"version", no_argument, 0, 'V'},
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{"releasewait", no_argument, 0, 'w'},
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{NULL, 0, NULL, 0}
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};
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static int request_cb(rd_device *d, int forced) {
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(void) d; // skip 'unused variable' compiler warning;
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(void) forced; // skip 'unused variable' compiler warning;
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fprintf(stdout, "Received higher priority request - releasing device.\n");
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fflush(stdout);
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if(!release_wait_for_signal) {
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usleep (500000);
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run = 0;
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} else if (run) {
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int timeout = 4000;
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fprintf(stdout, "Waiting for acknowledge signal to release.\n");
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while (release_wait_for_signal && run && --timeout) {
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if (!stdin_available()) {
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break;
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}
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if (parent_pid > 0 && kill (parent_pid, 0)) {
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break;
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}
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usleep (1000);
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}
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run = 0;
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}
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return 1; // OK
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}
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int main(int argc, char **argv) {
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DBusConnection* dbus_connection = NULL;
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rd_device * reserved_device = NULL;
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DBusError error;
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int ret, c;
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int32_t priority = INT32_MAX;
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char *name = strdup(ARD_APPL_NAME);
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while ((c = getopt_long (argc, argv,
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"h" /* help */
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"n:" /* name */
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"P:" /* pid */
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"p:" /* priority */
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"V" /* version */
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"w", /* release wait for signal */
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long_options, (int *) 0)) != EOF)
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{
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switch (c) {
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case 'h':
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free(name);
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usage ();
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break;
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case 'n':
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free(name);
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name = strdup(optarg);
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break;
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case 'p':
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priority = atoi (optarg);
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if (priority < 0) priority = 0;
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break;
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case 'P':
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parent_pid = atoi (optarg);
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break;
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case 'V':
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free(name);
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print_version ();
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break;
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case 'w':
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release_wait_for_signal = 1;
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break;
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default:
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free(name);
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fprintf (stderr, "Error: unrecognized option. See --help for usage information.\n");
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exit (EXIT_FAILURE);
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break;
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}
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}
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if (optind + 1 != argc) {
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fprintf (stderr, "Error: Missing parameter. See --help for usage information.\n");
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free(name);
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return EXIT_FAILURE;
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}
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const char *device_name = argv[optind];
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if (parent_pid > 0 && kill (parent_pid, 0)) {
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fprintf(stderr, "Given PID to watch is not running.\n");
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free(name);
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return EXIT_FAILURE;
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}
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dbus_error_init(&error);
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if (!(dbus_connection = dbus_bus_get (DBUS_BUS_SESSION, &error))) {
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fprintf(stderr, "Failed to connect to session bus for device reservation: %s\n", error.message ? error.message : "unknown error.");
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dbus_error_free(&error);
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free(name);
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return EXIT_FAILURE;
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}
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if ((ret = rd_acquire (
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&reserved_device,
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dbus_connection,
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device_name,
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name,
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priority,
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request_cb,
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&error)) < 0)
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{
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fprintf(stderr, "Failed to acquire device: '%s'\n%s\n", device_name, (error.message ? error.message : strerror(-ret)));
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dbus_error_free(&error);
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dbus_connection_unref(dbus_connection);
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free(name);
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return EXIT_FAILURE;
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}
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fprintf(stdout, "Acquired audio-card '%s'\n", device_name);
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fprintf(stdout, "Press Ctrl+C or close stdin to release the device.\n");
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fflush(stdout);
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signal(SIGTERM, wearedone);
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signal(SIGINT, wearedone);
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while (run && dbus_connection_read_write_dispatch (dbus_connection, 200)) {
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if (!stdin_available()) {
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fprintf(stderr, "stdin closed - releasing device.\n");
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break;
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}
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if (parent_pid > 0 && kill (parent_pid, 0)) {
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fprintf(stderr, "watched PID no longer exists - releasing device.\n");
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break;
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}
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}
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rd_release (reserved_device);
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fprintf(stdout, "Released audio-card '%s'\n", device_name);
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dbus_connection_unref(dbus_connection);
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dbus_error_free(&error);
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free(name);
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return EXIT_SUCCESS;
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}
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