[PATCH] make udev user callable to query the database

Here is a slightly better version that prints the usage if a unknown option is given:
  kay@pim:~/src/udev.kay$ ./udev -x
  ./udev: invalid option -- x
  Usage: [-qrVh]
    -q arg     query database
    -r         print udev root
    -V         print udev version
    -h         print this help text


> Here is a patch that makes it possible to call udev with options on the command line.
> Valid options are for now:
>
> -V for the udev version:
>     kay@pim:~/src/udev.kay$ ./udev -V
>     udev, version 011_bk
>
> -r for the udev root:
>     kay@pim:~/src/udev.kay$ ./udev -r
>     /udev/
>
> -q to query the database with the sysfs path for the name of the node:
>     kay@pim:~/src/udev.kay$ ./udev -q /class/video4linux/video0
>     test/video/webcam0

1 files changed, 13 insertions, 0 deletions

diff --git a/udevdb.c b/udevdb.c
index bbbeddad47..0f9de661a4 100644
--- a/udevdb.c
+++ b/udevdb.c
@@ -128,3 +128,16 @@ int udevdb_init(int init_flag)
 	}
 	return 0;
 }
+
+/**
+ * udevdb_init: open database for reading
+ */
+int udevdb_open_ro(void)
+{
+	udevdb = tdb_open(udev_db_filename, 0, 0, O_RDONLY, 0);
+	if (udevdb == NULL) {
+		dbg("unable to open database at '%s'", udev_db_filename);
+		return -EINVAL;
+	}
+	return 0;
+}