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authorHans Verkuil <hverkuil@xs4all.nl>2019-02-15 08:10:24 (GMT)
committerHans Verkuil <hverkuil-cisco@xs4all.nl>2019-02-15 14:35:18 (GMT)
commit51bca2a40095ac20fc775a4346bf71d6ff9f2552 (patch)
tree55b26808d19ad113e376ea0c6745ced56f8db16b
parentbb65901ea23701ef08344f3d357030b9d97d93a9 (diff)
media-ctl: support a bus-info string as argument to -d
If the device passed to the -d option is not found, then interpret it as a bus-info string and try to open all media devices and see which one reports a bus-info string equal to the -d argument. That makes it possible to open a specific media device without having to know the name of the media device. Similar functionality has been implemented for v4l2-ctl and v4l2-compliance, and for the cec utilities. This allows scripts that no longer need to care about the name of a device node, instead they can find it based on a unique string. Also extend the -d option to support -d0 as a shorthand for /dev/media0 to make it consistent with the other utils. Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
-rw-r--r--utils/media-ctl/options.c52
1 files changed, 51 insertions, 1 deletions
diff --git a/utils/media-ctl/options.c b/utils/media-ctl/options.c
index 1636785..fb92377 100644
--- a/utils/media-ctl/options.c
+++ b/utils/media-ctl/options.c
@@ -19,13 +19,18 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include <ctype.h>
+#include <dirent.h>
+#include <fcntl.h>
#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#include <sys/ioctl.h>
#include <unistd.h>
#include <v4l2subdev.h>
+#include <linux/media.h>
#include <linux/videodev2.h>
#include "options.h"
@@ -43,6 +48,9 @@ static void usage(const char *argv0)
printf("%s [options]\n", argv0);
printf("-d, --device dev Media device name (default: %s)\n", MEDIA_DEVNAME_DEFAULT);
+ printf(" If <dev> starts with a digit, then /dev/media<dev> is used.\n");
+ printf(" If <dev> doesn't exist, then find a media device that\n");
+ printf(" reports a bus info string equal to <dev>.\n");
printf("-e, --entity name Print the device name associated with the given entity\n");
printf("-V, --set-v4l2 v4l2 Comma-separated list of formats to setup\n");
printf(" --get-v4l2 pad Print the active format on a given pad\n");
@@ -161,6 +169,48 @@ static void list_known_mbus_formats(void)
}
}
+static const char *make_devname(const char *device)
+{
+ static char newdev[300];
+ struct dirent *ep;
+ DIR *dp;
+
+ if (!access(device, F_OK))
+ return device;
+
+ if (device[0] >= '0' && device[0] <= '9' && strlen(device) <= 3) {
+ snprintf(newdev, sizeof(newdev), "/dev/media%s", device);
+ return newdev;
+ }
+
+ dp = opendir("/dev");
+ if (dp == NULL)
+ return device;
+
+ while ((ep = readdir(dp))) {
+ const char *name = ep->d_name;
+
+ if (!memcmp(name, "media", 5) && isdigit(name[5])) {
+ struct media_device_info mdi;
+ int ret;
+ int fd;
+
+ snprintf(newdev, sizeof(newdev), "/dev/%s", name);
+ fd = open(newdev, O_RDWR);
+ if (fd < 0)
+ continue;
+ ret = ioctl(fd, MEDIA_IOC_DEVICE_INFO, &mdi);
+ close(fd);
+ if (!ret && !strcmp(device, mdi.bus_info)) {
+ closedir(dp);
+ return newdev;
+ }
+ }
+ }
+ closedir(dp);
+ return device;
+}
+
int parse_cmdline(int argc, char **argv)
{
int opt;
@@ -175,7 +225,7 @@ int parse_cmdline(int argc, char **argv)
opts, NULL)) != -1) {
switch (opt) {
case 'd':
- media_opts.devname = optarg;
+ media_opts.devname = make_devname(optarg);
break;
case 'e':

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