/*------------------------------------------------------------------------ * Copyright 2008-2009 (c) Jeff Brown * * This file is part of the ZBar Bar Code Reader. * * The ZBar Bar Code Reader is free software; you can redistribute it * and/or modify it under the terms of the GNU Lesser Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * The ZBar Bar Code Reader is distributed in the hope that it will be * useful, but WITHOUT ANY WARRANTY; without even the implied warranty * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser Public License for more details. * * You should have received a copy of the GNU Lesser Public License * along with the ZBar Bar Code Reader; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, * Boston, MA 02110-1301 USA * * http://sourceforge.net/projects/zbar *------------------------------------------------------------------------*/ #include #include #include #include #include #include #include #include #include #include typedef void (cb_t) (void *userdata, const char *device); struct devnodes { char *fname; int minor; int is_valid; }; static unsigned int n_devices = 0; static struct devnodes *devices = NULL; /* * Sort order: * * - Valid devices comes first * - Lowest minors comes first * * For devnode names, it sorts on this order: * - custom udev given names * - /dev/v4l/by-id/ * - /dev/v4l/by-path/ * - /dev/video * - /dev/char/ * * - Device name is sorted alphabetically if follows same pattern */ static int sort_devices(const void *__a, const void *__b) { const struct devnodes *a = __a; const struct devnodes *b = __b; int val_a, val_b; if (a->is_valid != b->is_valid) return !a->is_valid - !b->is_valid; if (a->minor != b->minor) return a->minor - b->minor; /* Ensure that /dev/video* devices will stay at the top */ if (strstr(a->fname, "by-id")) val_a = 1; if (strstr(a->fname, "by-path")) val_a = 2; else if (strstr(a->fname, "/dev/video")) val_a = 3; else if (strstr(a->fname, "char")) val_a = 4; else /* Customized names comes first */ val_a = 0; if (strstr(b->fname, "by-id")) val_b = 1; if (strstr(b->fname, "by-path")) val_b = 2; else if (strstr(b->fname, "/dev/video")) val_b = 3; else if (strstr(b->fname, "char")) val_b = 4; else /* Customized names comes first */ val_b = 0; if (val_a != val_b) return val_a - val_b; /* Finally, just use alphabetic order */ return strcmp(a->fname, b->fname); } static int handle_video_devs(const char *file, const struct stat *st, int flag) { int dev_minor, first_device = -1, fd; unsigned int i; struct v4l2_capability vid_cap = { 0 }; /* Discard devices that can't be a videodev */ if (!S_ISCHR(st->st_mode) || major(st->st_rdev) != 81) return 0; dev_minor = minor(st->st_rdev); /* check if it is an already existing device */ if (devices) { for (i = 0; i < n_devices; i++) { if (dev_minor == devices[i].minor) { first_device = i; break; } } } devices = realloc(devices, (n_devices + 1) * sizeof(struct devnodes)); if (!devices) { perror("Can't allocate memory to store devices"); exit(1); } memset(&devices[n_devices], 0, sizeof(struct devnodes)); if (first_device < 0) { fd = open(file, O_RDWR); if (fd < 0) { devices[n_devices].is_valid = 0; } else { if (ioctl(fd, VIDIOC_QUERYCAP, &vid_cap) == -1) { devices[n_devices].is_valid = 0; } else { #ifdef V4L2_CID_ALPHA_COMPONENT /* * device_caps was added on Kernel 3.3. The preferred * way to handle such compat stuff would be to include * a recent videodev2.h at ZBar's source and check the * V4L2 API returned by VIDIOC_QUERYCAP. * However, doing that require some care, as other * compat code should be checked to see if they would work. * Also, it is painful to keep updating the Kernel headers. * Thankfully, V4L2_CID_ALPHA_COMPONENT was also added on * Kernel 3.3, so just checking if this is defined should * be enough to do the right thing. */ if (!(vid_cap.device_caps & V4L2_CAP_VIDEO_CAPTURE)) devices[n_devices].is_valid = 0; else devices[n_devices].is_valid = 1; #else if (!(vid_cap.device_caps & V4L2_CAP_VIDEO_CAPTURE)) devices[n_devices].is_valid = 0; else devices[n_devices].is_valid = 1; #endif } } close(fd); } else { devices[n_devices].is_valid = devices[first_device].is_valid; } devices[n_devices].fname = strdup(file); devices[n_devices].minor = dev_minor; n_devices++; return(0); } /* scan /dev for v4l video devices and call add_device for each. * also looks for a specified "default" device (if not NULL) * if not found, the default will be appended to the list. * returns the index+1 of the default_device, or 0 if the default * was not specified. NB *not* reentrant */ int scan_video (cb_t add_dev, void *userdata, const char *default_dev) { unsigned int i, idx = 0; int default_idx = -1, last_minor = -1; if(ftw("/dev", handle_video_devs, 4)) { perror("search for video devices failed"); return -1; } qsort(devices, n_devices, sizeof(struct devnodes), sort_devices); for (i = 0; i < n_devices; i++) { if (!devices[i].is_valid) continue; if (devices[i].minor == last_minor) continue; add_dev(userdata, devices[i].fname); last_minor = devices[i].minor; idx++; if (default_dev && !strcmp(default_dev, devices[i].fname)) default_idx = idx; else if (!default_dev && default_idx < 0) default_idx = idx; } for (i = 0; i < n_devices; i++) free(devices[i].fname); free(devices); n_devices = 0; devices = NULL; return(default_idx); }