[libvirt] [PATCH] util: Don't try to fchown files opened as non-root

[Jiri Denemark]

On Fri, Jul 08, 2011 at 07:46:06 -0600, Eric Blake wrote:
> On 07/08/2011 07:30 AM, Jiri Denemark wrote:
> > When virFileOpenAs is called with VIR_FILE_OPEN_AS_UID flag and uid/gid
> > different from root/root while libvirtd is running as root, we fork a
> > new child, change its effective UID/GID to uid/gid and run
> > virFileOpenAsNoFork. It doesn't make any sense to fchown() the opened
> > file in this case since we already know that uid/gid can access the file
> > when open succeeds and one of the following situations may happen:
> > 
> > - the file is already owned by uid/gid and we skip fchown even before
> >   this patch
> > - the file is owned by uid but not gid because it was created in a
> >   directory with SETGID set, in which case it is desirable not to change
> >   the group
> > - the file may be owned by a completely different user and/or group
> >   because it was created on a root-squashed or even all-squashed NFS
> >   filesystem, in which case fchown would most likely fail anyway
> > ---
> >  src/util/util.c |   31 +++++++++++++++++++------------
> >  1 files changed, 19 insertions(+), 12 deletions(-)
> 
> ACK.
> 
> > +    /* VIR_FILE_OPEN_AS_UID in flags means we are running in a child process
> > +     * owned by uid and gid */
> > +    if (!(flags & VIR_FILE_OPEN_AS_UID)) {
> > +        struct stat st;
> > +        if (fstat(fd, &st) == -1) {
> 
> Style nit - add a newline between the declaration of st and the first
> statement (the nested if).

Fixed and pushed, thanks.

Jirka