Bug 193584
| Summary: | [autofs] problem when resolving maps with partial path matches | ||
|---|---|---|---|
| Product: | Base System | Reporter: | Bjoern A. Zeeb <bz> |
| Component: | bin | Assignee: | Edward Tomasz Napierala <trasz> |
| Status: | Closed FIXED | ||
| Severity: | Affects Some People | CC: | bz, david, emaste |
| Priority: | --- | ||
| Version: | CURRENT | ||
| Hardware: | Any | ||
| OS: | Any | ||
Looks as if this explains why I was seeing some odd results: I had started testing to see if we could migrate from using amd(8) to autofs, and I was seeing the contents of /volume/build/ when I was looking for /volume/buildtools/. That's a bit ... awkward. (Other than a moderate delay on first reference to an automounted directory -- with >28K lines in the maps, that's not entirely surprising -- it seemed to be working OK other than this ("partial path matches") issue.)
Oh: my testing was on FreeBSD 10.1-BETA2 #21 r271873: Fri Sep 19 09:07:42 PDT 2014 (amd64).
Anyway: Looks as if this is a show-stopper in my case.
Guys, can you test 11-CURRENT to see if it's fixed properly? A commit references this bug: Author: trasz Date: Tue Sep 23 19:12:06 UTC 2014 New revision: 272037 URL: http://svnweb.freebsd.org/changeset/base/272037 Log: Fix thinko that, with two map entries like shown below, in that order, made automountd(8) mix them up: trying to access the second one would trigger mount for the first one. foo host:/foo foobar host:/foobar PR: 193584 MFC after: 3 days Sponsored by: The FreeBSD Foundation Changes: head/usr.sbin/autofs/common.c A slightly different conditions to properly check the escape condition. Updating of my HEAD is on the way; also to pick up the kernel change. I'll report back, probably tomorrow morning. Works like a charm now! Thanks a lot for fixing. Please MFC before BETA3/RC1 :-) A commit references this bug: Author: trasz Date: Thu Sep 25 17:38:43 UTC 2014 New revision: 272117 URL: http://svnweb.freebsd.org/changeset/base/272117 Log: MFC r272037: Fix thinko that, with two map entries like shown below, in that order, made automountd(8) mix them up: trying to access the second one would trigger mount for the first one. foo host:/foo foobar host:/foobar PR: 193584 Approved by: re (gjb) Sponsored by: The FreeBSD Foundation Changes: _U stable/10/ stable/10/usr.sbin/autofs/common.c David, can you test it? The fix will be there in BETA3. Sorry for delay; Yes: I was able to test on my test machine at work (now running 10.1-BETA3 @r272180), and this issue appears to be resolved for me. [I *thought* I had tried hand-applying the patch & rebuilding, but that didn't resolve it -- that's (mostly) why I waited until the MFC.] Thanks! |
When an indirect map returns: ... /auto/foo/www /auto/foo/www-bar /auto/foo/www-baz and we are looking up www-bar the strncmp in node_find() will match on www already and try to mount that; if parts of the path are expanded from the key facilitating the & we might try to mount /auto/foo/www-baz from filer:/totally/different/path/& I have tried to figure out how to fix that strncmp without much luck running into other assertion failures due to path being an empty string for the initial map lookup it seemed, so I added some extra comparison to the child loop, which should catch all cases still but handling a possible trailing / makes it look ugly. Trying to avoid a possible strdup() failure, I am using two strlen() and a strncmp() on the longer path; obviously one could also check the lens to be equal first. Here's a part of the diff with all debugging etc. in it still: @@ -674,19 +674,41 @@ node_find(struct node *node, const char *path) struct node *child, *found; char *tmp; - //log_debugx("looking up %s in %s", path, node->n_key); + log_debugx("looking up %s in %s", path, node->n_key); tmp = node_path(node); +#if 1 if (strncmp(tmp, path, strlen(tmp)) != 0) { +#else + log_debugx("comparing '%s' '%s' %zu %zu", tmp, path, strlen(path), strlen(tmp)); + if (strlen(tmp) != 0 && strncmp(tmp, path, strlen(tmp)) != 0) { +#endif free(tmp); return (NULL); } free(tmp); + node_print(node); TAILQ_FOREACH(child, &node->n_children, n_next) { found = node_find(child, path); - if (found != NULL) - return (found); + if (found != NULL) { + size_t pl, tl; + + tmp = node_path(found); + log_debugx("found candidate %s %s %s", tmp, path, found->n_key); + /* node_path() already removes a possible trainling '/'. */ + tl = strlen(tmp); + pl = strlen(path); + if (path[pl-1] == '/') + pl--; + pl = (pl > tl) ? pl : tl; + if (strncmp(tmp, path, pl) == 0) { + log_debugx("found match %s %s %s %zu", tmp, path, found->n_key, pl); + free(tmp); + return (found); + } + free(tmp); + } } return (node); I am sure there is a better, proper solution and I am willing to test.