site_archiver@lists.apple.com Delivered-To: darwin-kernel@lists.apple.com User-agent: Thunderbird 2.0.0.0 (Macintosh/20070326) Our path length overall is very small, so we wont be hitting DEVMAXNAMESIZE. - strncpy(component, start, scan - start); - component[ scan - start ] = '\0'; + strlcpy(component, start, scan - start); if (*scan == '/') scan++; You can see the bug. For this to be correct it should look like this: strlcpy(component, start, scan - start + 1); Nick _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.a... Terry Lambert wrote: On Nov 8, 2007, at 9:02 PM, Nick Blievers wrote: Also, if you look at Leopard sources for devfs, you will see that there is a mechanism for creating directories, but there is no KPI published for it, and its use is therefore completely unsipported and subject to change; however, it does exist. Again we are not trying to create directories directly, they are created as a by-product of calling devfs_make_node() with a full path, which the comments say (when calling dev_finddir()) acts like a mkdir -p. Are you sure you are not running into the fact that we now enforce DEVMAXNAMESIZE, instead of copying off into random memory at the end of the structure? There is a limit of 32 bytes on the path length, including all component separators. If you hack and use the unpublished method, be aware that the a_dvp needs to point to the directory in which the node is being created, so you have to do it by basing it there, rather than at the root of devfs. Specifically path component separators are not recognized. devfs_make_node() is a published method... that used to allow the creation of directories within /dev. It still does provide that functionality, just truncating one of the path elements due to an off by one error. Also FWIW: This is exactly what I told you in the radar. Sort of. I really think we are talking at cross purposes here. I am not trying to do anything new and different from whats been done previously, and I am certainly not trying to make life difficult for you. Its just that, as far as I am aware, I am using a published interface that has had a behaviour change from Tiger to Leopard, due to an off by one error. Thanks for the detailed feedback, and while I will obviously look for alternate solutions (since calling devfs_make_node("/dev/fooX/bah") really sucks), I still maintain that this is a regression. Please file a radar. This was not clear from your previous radar (in which we did resolve an off-by-one error), and as long as you are not bumping into DEVMAXNAMESIZE, we would need a radar number to hang the work off of, even if we knew it was a bug. If we look at a diff between tiger and leopard code (I hope its ok for me to post this here) --- /Developer/Darwin-8.9.0/xnu-792.17.14/bsd/miscfs/devfs/devfs_tree.c 2007-04-18 09:19:56.000000000 +0800 +++ /Developer/Darwin-9.0.0/xnu-1228//bsd/miscfs/devfs/devfs_tree.c 2007-10-30 11:58:56.000000000 +0800 @@ -266,8 +292,7 @@ while (*scan != '/' && *scan) scan++; This minor problem has changed the way devfs_make_node() works, which is what I have been trying (and failing obviously!) to say. Other places in this file where the conversion from strncpy() to strlcpy() occurred have the extra +1, so it seems this case was just overlooked. Sorry if I caused some confusion with these posts and bug reports... didn't mean to get off on the wrong foot! I have an RFE open (#5589808) as that appeared the only option after #5584196 was dup'd. Is that enough, or do you want me to raise another bug? This email sent to site_archiver@lists.apple.com