[libvirt PATCH 06/32] util: use getgrouplist() directly instead of mgetgroups

[Daniel P. Berrangé]

On Mon, Jan 27, 2020 at 12:44:01PM +0100, Pavel Hrdina wrote:
> On Thu, Jan 23, 2020 at 11:42:59AM +0000, Daniel P. Berrangé wrote:
> > The mgetgroups function is a GNULIB custom wrapper around
> > getgrouplist(). This implements a simplified version of
> > that code directly.
> > 
> > Signed-off-by: Daniel P. Berrangé <berrange at redhat.com>
> > ---
> >  src/internal.h     |  4 ++++
> >  src/util/virutil.c | 34 ++++++++++++++++++++++++++++------
> >  2 files changed, 32 insertions(+), 6 deletions(-)
> > 
> > diff --git a/src/util/virutil.c b/src/util/virutil.c
> > index 87ca16c088..4bc0aef35f 100644
> > --- a/src/util/virutil.c
> > +++ b/src/util/virutil.c
> > @@ -1000,11 +1004,27 @@ virGetGroupList(uid_t uid, gid_t gid, gid_t **list)
> >      /* invalid users have no supplementary groups */
> >      if (uid != (uid_t)-1 &&
> >          virGetUserEnt(uid, &user, &primary, NULL, NULL, true) >= 0) {
> > -        if ((ret = mgetgroups(user, primary, list)) < 0) {
> > -            virReportSystemError(errno,
> > -                                 _("cannot get group list for '%s'"), user);
> > -            ret = -1;
> > -            goto cleanup;
> > +        int nallocgrps = 10;
> > +        gid_t *grps = g_new(gid_t, nallocgrps);
> 
> This is never used anywhere except in the while loop.

The loop relies on the "grps" pointer being persistent across
loop iterations though.

> 
> > +        while (1) {
> > +            int nprevallocgrps = nallocgrps;
> > +            int rv;
> > +
> > +            rv = getgrouplist(user, primary, grps, &nallocgrps);
> > +
> > +            /* Some systems (like Darwin) have a bug where they
> > +               never increase max_n_groups.  */
> > +            if (rv < 0 && nprevallocgrps == nallocgrps)
> > +                nallocgrps *= 2;
> > +
> > +            /* either shrinks to actual size, or enlarges tonew size */
> 
> s/tonew/to new/
> 
> > +            grps = g_renew(gid_t, grps, nallocgrps);
> > +
> > +            if (rv >= 0) {
> > +                ret = rv;
> > +                break;
> 
> Based on the GNULIB implementation here we should set *list = grps.

Yes.

> 
> With that fixed:
> 
> Reviewed-by: Pavel Hrdina <phrdina at redhat.com>



Regards,
Daniel
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