dbus/device_reservation.c

   1 /*
   2     Copyright (C) 2009 Grame
   3     Copyright (C) 2024 Nedko Arnaudov
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17
  18 */
  19
  20 #include <string.h>
  21 #include <unistd.h>
  22 #include <errno.h>
  23 #include <stdlib.h>
  24 #include <stdio.h>
  25 #include <assert.h>
  26 #include <stdint.h>
  27
  28 #include "reserve.h"
  29 #include "device_reservation.h"
  30 #include "jack/control.h"
  31
  32 #define DEVICE_MAX 2
  33
  34 /* string like "Audio2", "Midi5" or "Video3" */
  35 #define MAX_DEVICE_NAME 63
  36
  37 typedef struct reserved_audio_device {
  38
  39      char device_name[MAX_DEVICE_NAME+1];
  40      rd_device * reserved_device;
  41
  42 } reserved_audio_device;
  43
  44 static DBusConnection* gConnection = NULL;
  45 static reserved_audio_device gReservedDevice[DEVICE_MAX];
  46 static int gReserveCount = 0;
  47
  48 int device_reservation_init(void)
  49 {
  50     DBusError error;
  51     dbus_error_init(&error);
  52
  53     if (!(gConnection = dbus_bus_get(DBUS_BUS_SESSION, &error))) {
  54         jack_error("Failed to connect to session bus for device reservation: %s\n", error.message);
  55         return -1;
  56     }
  57
  58     jack_info("audio_reservation_init");
  59     return 0;
  60 }
  61
  62 int device_reservation_finish(void)
  63 {
  64     if (gConnection) {
  65         dbus_connection_unref(gConnection);
  66         gConnection = NULL;
  67         jack_info("audio_reservation_finish");
  68     }
  69     return 0;
  70 }
  71
  72 bool device_reservation_acquire(const char * device_name)
  73 {
  74     DBusError error;
  75     int ret;
  76
  77     // Open DBus connection first time
  78     if (gReserveCount == 0) {
  79         if (device_reservation_init() != 0) {
  80             return false;
  81         }
  82     }
  83
  84     assert(gReserveCount < DEVICE_MAX);
  85
  86     if (gReserveCount != 0) {
  87         jack_error("Ignoring reservation for more than one device (acquire)");
  88         return false;
  89     }
  90
  91     strncpy(gReservedDevice[gReserveCount].device_name, device_name, MAX_DEVICE_NAME);
  92     if (strcmp(gReservedDevice[gReserveCount].device_name, device_name) != 0)
  93     {
  94         jack_error("Ignoring reservation for device with too long name");
  95         return false;
  96     }
  97
  98     dbus_error_init(&error);
  99
 100     if ((ret= rd_acquire(
 101                  &gReservedDevice[gReserveCount].reserved_device,
 102                  gConnection,
 103                  device_name,
 104                  "Jack audio server",
 105                  INT32_MAX,
 106                  NULL,
 107                  &error)) < 0) {
 108
 109         jack_error("Failed to acquire device name : %s error : %s", device_name, (error.message ? error.message : strerror(-ret)));
 110         dbus_error_free(&error);
 111         return false;
 112     }
 113
 114     gReserveCount++;
 115     jack_info("Acquire audio card %s", device_name);
 116     return true;
 117 }
 118
 119 void device_reservation_release(const char * device_name)
 120 {
 121     int i;
 122
 123     // Look for corresponding reserved device
 124     for (i = 0; i < DEVICE_MAX; i++) {
 125         if (strcmp(gReservedDevice[i].device_name, device_name) == 0)
 126             break;
 127     }
 128
 129     if (i < DEVICE_MAX) {
 130         jack_info("Released audio card %s", device_name);
 131         rd_release(gReservedDevice[i].reserved_device);
 132     } else {
 133         jack_error("Audio card %s not found!!", device_name);
 134     }
 135
 136     // Close DBus connection last time
 137     gReserveCount--;
 138     if (gReserveCount == 0)
 139         device_reservation_finish();
 140 }
 141
 142 void device_reservation_loop(void)
 143 {
 144     if (gConnection != NULL) {
 145        dbus_connection_read_write_dispatch (gConnection, 200);
 146     }
 147 }
 148