Hi Hans, Thank you for the patch.
On Fri, Feb 15, 2019 at 09:10:24AM +0100, Hans Verkuil wrote: > 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-ci...@xs4all.nl> > --- > Changes since v1: > - fold into the -d option instead of creating a separate option > --- > diff --git a/utils/media-ctl/options.c b/utils/media-ctl/options.c > index 16367857..fb923775 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]; 300 is still a lot for such a short string. > + 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); Did openat() fail ? > + 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': -- Regards, Laurent Pinchart
