1 /* 2 * libjingle 3 * Copyright 2009 Google Inc. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright notice, 9 * this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright notice, 11 * this list of conditions and the following disclaimer in the documentation 12 * and/or other materials provided with the distribution. 13 * 3. The name of the author may not be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO 19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 /* 29 * Author: lexnikitin (at) google.com (Alexey Nikitin) 30 * 31 * V4LLookup provides basic functionality to work with V2L2 devices in Linux 32 * The functionality is implemented as a class with virtual methods for 33 * the purpose of unit testing. 34 */ 35 #include "talk/media/devices/v4llookup.h" 36 37 #include <errno.h> 38 #include <fcntl.h> 39 #include <linux/types.h> 40 #include <linux/videodev2.h> 41 #include <string.h> 42 #include <sys/ioctl.h> 43 #include <sys/stat.h> 44 #include <sys/types.h> 45 #include <unistd.h> 46 47 #include "webrtc/base/logging.h" 48 49 namespace cricket { 50 51 V4LLookup *V4LLookup::v4l_lookup_ = NULL; 52 53 bool V4LLookup::CheckIsV4L2Device(const std::string& device_path) { 54 // check device major/minor numbers are in the range for video devices. 55 struct stat s; 56 57 if (lstat(device_path.c_str(), &s) != 0 || !S_ISCHR(s.st_mode)) return false; 58 59 int video_fd = -1; 60 bool is_v4l2 = false; 61 62 // check major/minur device numbers are in range for video device 63 if (major(s.st_rdev) == 81) { 64 dev_t num = minor(s.st_rdev); 65 if (num <= 63) { 66 video_fd = ::open(device_path.c_str(), O_RDONLY | O_NONBLOCK); 67 if ((video_fd >= 0) || (errno == EBUSY)) { 68 ::v4l2_capability video_caps; 69 memset(&video_caps, 0, sizeof(video_caps)); 70 71 if ((errno == EBUSY) || 72 (::ioctl(video_fd, VIDIOC_QUERYCAP, &video_caps) >= 0 && 73 (video_caps.capabilities & V4L2_CAP_VIDEO_CAPTURE))) { 74 LOG(LS_INFO) << "Found V4L2 capture device " << device_path; 75 76 is_v4l2 = true; 77 } else { 78 LOG_ERRNO(LS_ERROR) << "VIDIOC_QUERYCAP failed for " << device_path; 79 } 80 } else { 81 LOG_ERRNO(LS_ERROR) << "Failed to open " << device_path; 82 } 83 } 84 } 85 86 if (video_fd >= 0) 87 ::close(video_fd); 88 89 return is_v4l2; 90 } 91 92 }; // namespace cricket 93
