components/volume.c

   1 /* See LICENSE file for copyright and license details. */
   2 #include <fcntl.h>
   3 #include <stdio.h>
   4 #include <string.h>
   5 #if defined(__OpenBSD__)
   6         #include <soundcard.h>
   7 #else
   8         #include <sys/soundcard.h>
   9 #endif
  10 #include <sys/ioctl.h>
  11 #include <unistd.h>
  12
  13 #include "../util.h"
  14
  15 const char *
  16 vol_perc(const char *card)
  17 {
  18         size_t i;
  19         int v, afd, devmask;
  20         char *vnames[] = SOUND_DEVICE_NAMES;
  21
  22         if ((afd = open(card, O_RDONLY | O_NONBLOCK)) < 0) {
  23                 warn("open '%s':", card);
  24                 return NULL;
  25         }
  26
  27         if (ioctl(afd, (int)SOUND_MIXER_READ_DEVMASK, &devmask) < 0) {
  28                 warn("ioctl 'SOUND_MIXER_READ_DEVMASK':");
  29                 close(afd);
  30                 return NULL;
  31         }
  32         for (i = 0; i < LEN(vnames); i++) {
  33                 if (devmask & (1 << i) && !strcmp("vol", vnames[i])) {
  34                         if (ioctl(afd, MIXER_READ(i), &v) < 0) {
  35                                 warn("ioctl 'MIXER_READ(%ld)':", i);
  36                                 close(afd);
  37                                 return NULL;
  38                         }
  39                 }
  40         }
  41
  42         close(afd);
  43
  44         return bprintf("%d", v & 0xff);
  45 }