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/*------------------------------------------------------------------------
* Copyright 2008-2009 (c) Jeff Brown <spadix@users.sourceforge.net>
*
* 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 "config.h"
#include <fcntl.h>
#include <ftw.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <linux/videodev2.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#ifdef MAJOR_IN_SYSMACROS
#include <sys/sysmacros.h>
#endif
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);
}
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