[PATCH] Sanitizing netif-rename code

[Matthias Schwarzott <zzam@gentoo.org>]

[-- Attachment #1: Type: text/plain, Size: 859 bytes --]

Hi there!

The attached patch comes origins from this Bugreport:
http://bugs.gentoo.org/show_bug.cgi?id=158531

The original code from udev_device.c / function rename_netif looks like this:
while (loop--) {
	retval = ioctl(sk, SIOCSIFNAME, &ifr);
	if (retval != 0) {
		if (errno != EEXIST) {
			err("error changing net interface name %s to %s: %s",
				ifr.ifr_name, ifr.ifr_newname, strerror(errno));
			break;
		}
		dbg("wait for netif '%s' to become free, loop=%i", udev->name, (30 * 20) -
			loop);
		usleep(1000 * 1000 / 20);
	}
}


In some loop the rename-syscall will succeed, and retval is 0.
In this case the loop is not left, but just retried the loop and executing the 
rename code over and over again.

Attached patch adds something similar to that (inside the loop):
if (retval == 0)
	break;

Greetings
  Matthias

-- 
Matthias Schwarzott (zzam)

[-- Attachment #2: udev-103-busywait.patch --]
[-- Type: text/x-diff, Size: 876 bytes --]

diff -Nur udev-103old/udev_device.c udev-103/udev_device.c
--- udev-103old/udev_device.c	2006-10-20 14:43:35.000000000 +0200
+++ udev-103/udev_device.c	2006-12-20 12:04:52.000000000 +0100
@@ -122,16 +122,18 @@
 		strlcpy(ifr.ifr_newname, udev->name, IFNAMSIZ);
 		loop = 30 * 20;
 		while (loop--) {
-			retval = ioctl(sk, SIOCSIFNAME, &ifr);	
-			if (retval != 0) {
+			retval = ioctl(sk, SIOCSIFNAME, &ifr);
+			if (retval == 0) {
+				break;
+			} else {
 				if (errno != EEXIST) {
 					err("error changing net interface name %s to %s: %s",
 					    ifr.ifr_name, ifr.ifr_newname, strerror(errno));
 					break;
 				}
-				dbg("wait for netif '%s' to become free, loop=%i", udev->name, (30 * 20) - loop);
-				usleep(1000 * 1000 / 20);
 			}
+			dbg("wait for netif '%s' to become free, loop=%i", udev->name, (30 * 20) - loop);
+			usleep(1000 * 1000 / 20);
 		}
 	}
 

[-- Attachment #3: Type: text/plain, Size: 347 bytes --]

-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys - and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV

[-- Attachment #4: Type: text/plain, Size: 226 bytes --]

_______________________________________________
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