[PATCH] cyrus-imapd: use getgrouplist instead of set/getgrent on systems supporting it

[Ken Murchison]

Tomas Janousek wrote:
> Hello,
> 
> On Mon, Sep 17, 2007 at 09:49:38AM -0400, Ken Murchison wrote:
>> I applied Simon's version to CVS, but then I realized that it causes 
>> myfreestate() to crash on my Linux box, because the newstate->groups array 
>> doesn't get entirely populated.  The following patch fixes the problem of 
> 
> Oh, sorry for that.
> 
>> having gaps in newstate->groups, but I'm not sure why we're skipping groups 
>> anyways.  Also, will getgrouplist() really return -1 for anything other than 
>> the output array being too small (wondering if we need the 'do' loop)?
> 
> Yes, it returns -1 also in case of an error. It's not in the manpage but I
> looked at the glibc sources (at the time when I wrote the patch, so I may be
> inaccurate).
> 
>> --- auth_unix.c.~1.42.~	2007-09-13 13:24:42.000000000 -0400
>> +++ auth_unix.c	2007-09-17 09:38:45.000000000 -0400
>> @@ -270,11 +270,14 @@
>>  	goto err;
>>      }
>>
>> -    newstate->group = (char **)xmalloc(newstate->ngroups * sizeof(char *));
>> -    for (i = 0; i < newstate->ngroups; ++i ) {
>> +    newstate->ngroups = 0;
>> +    newstate->group = (char **)xmalloc(ngroups * sizeof(char *));
> 
> ngroups needn't be the same as newstate->ngroups, I think.

Right.  I changed the getgrouplist() calls to write to ngroups, rather 
than newstate->ngroups, so that ngroups always holds the most recent 
value, and newstate->ngroups holds the previous value.

Can you explain  the use of:

if (pwd || groupids[ngroups] != gid)

-- 
Kenneth Murchison
Systems Programmer
Project Cyrus Developer/Maintainer
Carnegie Mellon University