src/udev/v4l_id/v4l_id.c

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * Copyright (c) 2009 Filippo Argiolas <filippo.argiolas@gmail.com>
   4  */
   5
   6 #include <fcntl.h>
   7 #include <getopt.h>
   8 #include <linux/videodev2.h>
   9 #include <stdio.h>
  10 #include <sys/ioctl.h>
  11
  12 #include "build.h"
  13 #include "errno-util.h"
  14 #include "fd-util.h"
  15 #include "log.h"
  16 #include "main-func.h"
  17
  18 static const char *arg_device = NULL;
  19
  20 static int parse_argv(int argc, char *argv[]) {
  21         static const struct option options[] = {
  22                 { "help",     no_argument, NULL, 'h' },
  23                 { "version",  no_argument, NULL, 'v' },
  24                 {}
  25         };
  26         int c;
  27
  28         while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)
  29                 switch (c) {
  30                 case 'h':
  31                         printf("%s [OPTIONS...] DEVICE\n\n"
  32                                "Video4Linux device identification.\n\n"
  33                                "  -h --help     Show this help text\n"
  34                                "     --version  Show package version\n",
  35                                program_invocation_short_name);
  36                         return 0;
  37                 case 'v':
  38                         return version();
  39                 case '?':
  40                         return -EINVAL;
  41                 default:
  42                         assert_not_reached();
  43                 }
  44
  45         if (!argv[optind])
  46                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
  47                                        "DEVICE argument missing.");
  48
  49         arg_device = argv[optind];
  50         return 1;
  51 }
  52
  53 static int run(int argc, char *argv[]) {
  54         _cleanup_close_ int fd = -EBADF;
  55         struct v4l2_capability v2cap;
  56         int r;
  57
  58         r = parse_argv(argc, argv);
  59         if (r <= 0)
  60                 return r;
  61
  62         fd = open(arg_device, O_RDONLY|O_CLOEXEC|O_NOCTTY);
  63         if (fd < 0) {
  64                 bool ignore = ERRNO_IS_DEVICE_ABSENT(errno);
  65                 log_full_errno(ignore ? LOG_DEBUG : LOG_WARNING, errno,
  66                                "Failed to open device node '%s'%s: %m",
  67                                arg_device, ignore ? ", ignoring" : "");
  68                 return ignore ? 0 : -errno;
  69         }
  70
  71         if (ioctl(fd, VIDIOC_QUERYCAP, &v2cap) == 0) {
  72                 int capabilities;
  73
  74                 printf("ID_V4L_VERSION=2\n");
  75                 printf("ID_V4L_PRODUCT=%s\n", v2cap.card);
  76                 printf("ID_V4L_CAPABILITIES=:");
  77
  78                 if (v2cap.capabilities & V4L2_CAP_DEVICE_CAPS)
  79                         capabilities = v2cap.device_caps;
  80                 else
  81                         capabilities = v2cap.capabilities;
  82
  83                 if ((capabilities & V4L2_CAP_VIDEO_CAPTURE) > 0 ||
  84                     (capabilities & V4L2_CAP_VIDEO_CAPTURE_MPLANE) > 0)
  85                         printf("capture:");
  86                 if ((capabilities & V4L2_CAP_VIDEO_OUTPUT) > 0 ||
  87                     (capabilities & V4L2_CAP_VIDEO_OUTPUT_MPLANE) > 0)
  88                         printf("video_output:");
  89                 if ((capabilities & V4L2_CAP_VIDEO_OVERLAY) > 0)
  90                         printf("video_overlay:");
  91                 if ((capabilities & V4L2_CAP_AUDIO) > 0)
  92                         printf("audio:");
  93                 if ((capabilities & V4L2_CAP_TUNER) > 0)
  94                         printf("tuner:");
  95                 if ((capabilities & V4L2_CAP_RADIO) > 0)
  96                         printf("radio:");
  97                 printf("\n");
  98         }
  99
 100         return 0;
 101 }
 102
 103 DEFINE_MAIN_FUNCTION(run);