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1 /* | |
2 * Copyright (c) 2009 The WebRTC project authors. All Rights Reserved. | |
3 * | |
4 * Use of this source code is governed by a BSD-style license | |
5 * that can be found in the LICENSE file in the root of the source | |
6 * tree. An additional intellectual property rights grant can be found | |
7 * in the file PATENTS. All contributing project authors may | |
8 * be found in the AUTHORS file in the root of the source tree. | |
9 */ | |
10 | |
11 /* | |
12 * Author: lexnikitin@google.com (Alexey Nikitin) | |
13 * | |
14 * V4LLookup provides basic functionality to work with V2L2 devices in Linux | |
15 * The functionality is implemented as a class with virtual methods for | |
16 * the purpose of unit testing. | |
17 */ | |
18 #include "webrtc/media/devices/v4llookup.h" | |
19 | |
20 #include <errno.h> | |
21 #include <fcntl.h> | |
22 #include <linux/types.h> | |
23 #include <linux/videodev2.h> | |
24 #include <string.h> | |
25 #include <sys/ioctl.h> | |
26 #include <sys/stat.h> | |
27 #include <sys/types.h> | |
28 #include <unistd.h> | |
29 | |
30 #include "webrtc/base/logging.h" | |
31 | |
32 namespace cricket { | |
33 | |
34 V4LLookup *V4LLookup::v4l_lookup_ = NULL; | |
35 | |
36 bool V4LLookup::CheckIsV4L2Device(const std::string& device_path) { | |
37 // check device major/minor numbers are in the range for video devices. | |
38 struct stat s; | |
39 | |
40 if (lstat(device_path.c_str(), &s) != 0 || !S_ISCHR(s.st_mode)) return false; | |
41 | |
42 int video_fd = -1; | |
43 bool is_v4l2 = false; | |
44 | |
45 // check major/minur device numbers are in range for video device | |
46 if (major(s.st_rdev) == 81) { | |
47 dev_t num = minor(s.st_rdev); | |
48 if (num <= 63) { | |
49 video_fd = ::open(device_path.c_str(), O_RDONLY | O_NONBLOCK); | |
50 if ((video_fd >= 0) || (errno == EBUSY)) { | |
51 ::v4l2_capability video_caps; | |
52 memset(&video_caps, 0, sizeof(video_caps)); | |
53 | |
54 if ((errno == EBUSY) || | |
55 (::ioctl(video_fd, VIDIOC_QUERYCAP, &video_caps) >= 0 && | |
56 (video_caps.capabilities & V4L2_CAP_VIDEO_CAPTURE))) { | |
57 LOG(LS_INFO) << "Found V4L2 capture device " << device_path; | |
58 | |
59 is_v4l2 = true; | |
60 } else { | |
61 LOG_ERRNO(LS_ERROR) << "VIDIOC_QUERYCAP failed for " << device_path; | |
62 } | |
63 } else { | |
64 LOG_ERRNO(LS_ERROR) << "Failed to open " << device_path; | |
65 } | |
66 } | |
67 } | |
68 | |
69 if (video_fd >= 0) | |
70 ::close(video_fd); | |
71 | |
72 return is_v4l2; | |
73 } | |
74 | |
75 }; // namespace cricket | |
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