[PATCH] prevent unlinking moved symlinks

[John K Luebs <jkluebs@luebsphoto.com>]

Here's a fairly obvious fix; so someone please check it carefully.

This patch causes the remove handler to check that each symlink
actually points to the correct devnode and skip it if it does not.
The current policy for symlinks in devnode add handling is to "move" the
link if it exists, so when an old devnode is being removed its stored
symlink entries might be stale.

Signed-off-by: John K. Luebs <jkluebs@luebsphoto.com>

diff -pur udev-054/udev_remove.c udev-054-new/udev_remove.c
--- udev-054/udev_remove.c	2005-02-25 22:18:21.000000000 -0500
+++ udev-054-new/udev_remove.c	2005-03-08 00:13:46.000000000 -0500
@@ -90,6 +90,31 @@ static int delete_node(struct udevice *u
 		return -1;
 	}
 
+	foreach_strpart(udev->symlink, " ", pos, len) {
+		char linkname[NAME_SIZE];
+		char linkpath[NAME_SIZE];
+
+		strfieldcpymax(linkname, pos, len+1);
+		snprintf(linkpath, NAME_SIZE, "%s/%s", udev_root, linkname);
+		linkpath[NAME_SIZE-1] = '\0';
+
+		if ((stat(linkpath, &stats) != 0) || (stats.st_rdev != udev->devt))
+			continue;
+
+		dbg("unlinking symlink '%s'", linkpath);
+		retval = unlink(linkpath);
+		if (errno = ENOENT)
+			retval = 0;
+		if (retval) {
+			dbg("unlink(%s) failed with error '%s'",
+				linkpath, strerror(errno));
+			return retval;
+		}
+		if (strchr(udev->symlink, '/')) {
+			delete_path(linkpath);
+		}
+	}
+
 	info("removing device node '%s'", filename);
 	retval = unlink_secure(filename);
 	if (retval)
@@ -114,27 +139,6 @@ static int delete_node(struct udevice *u
 	if (strchr(udev->name, '/'))
 		delete_path(filename);
 
-	foreach_strpart(udev->symlink, " ", pos, len) {
-		char linkname[NAME_SIZE];
-
-		strfieldcpymax(linkname, pos, len+1);
-		snprintf(filename, NAME_SIZE, "%s/%s", udev_root, linkname);
-		filename[NAME_SIZE-1] = '\0';
-
-		dbg("unlinking symlink '%s'", filename);
-		retval = unlink(filename);
-		if (errno = ENOENT)
-			retval = 0;
-		if (retval) {
-			dbg("unlink(%s) failed with error '%s'",
-				filename, strerror(errno));
-			return retval;
-		}
-		if (strchr(udev->symlink, '/')) {
-			delete_path(filename);
-		}
-	}
-
 	return retval;
 }
 



-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now.
http://ads.osdn.com/?ad_ide95&alloc_id\x14396&op=click
_______________________________________________
Linux-hotplug-devel mailing list  http://linux-hotplug.sourceforge.net
Linux-hotplug-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel