Re: [libvirt] [PATCH v2] storage: Check for invalid storage mode before opening
On 05/21/2010 11:03 AM, Cole Robinson wrote:
If a directory pool contains pipes or sockets, a pool start can fail
or hang:
https://bugzilla.redhat.com/show_bug.cgi?id=589577
We already try to avoid these special files, but only attempt after
opening the path, which is where the problems lie. Unify volume opening
into a single function which runs stat() before any open() call. Directory
This sentence of the commit log is out-of-date...
pools can then proceed along, ignoring the invalid files.
v2: Use ATTRIBUTE_NONNULL. Drop stat check, just open with
O_NONBLOCK|O_NOCTTY.
...given this sentence.
+int
+virStorageBackendVolOpen(const char *path)
+{
+ int fd;
+
+ if ((fd = open(path, O_RDONLY|O_NONBLOCK|O_NOCTTY)) < 0) {
+ virReportSystemError(errno,
+ _("cannot open volume '%s'"),
+ path);
+ return -1;
+ }
I'm thinking that we still want to use fstat() (after the open()) and
reject directories, sockets, and pipes (or more accurately, accept only
regular files, block devices, and possibly character devices).
In other words, you got rid of the stat/open race (good), but also got
rid of the strictness provided by validating [f]stat (not so good).
Probably worth a v3, so we get virStorageBackendVolOpen right.
--
Eric Blake eblake(a)redhat.com +1-801-349-2682
Libvirt virtualization library http://libvirt.org
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