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/* getugroups.c -- return a list of the groups a user is in
Copyright (C) 1990, 1991, 1998-2000, 2003-2008 Free Software Foundation.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* Written by David MacKenzie. */
#include <config.h>
#include "getugroups.h"
#include <limits.h>
#include <stdio.h> /* grp.h on alpha OSF1 V2.0 uses "FILE *". */
#include <grp.h>
#include <unistd.h>
#include <errno.h>
/* Some old header files might not declare setgrent, getgrent, and endgrent.
If you don't have them at all, we can't implement this function.
You lose! */
struct group *getgrent ();
#include <string.h>
#define STREQ(s1, s2) ((strcmp (s1, s2) == 0))
/* Like `getgroups', but for user USERNAME instead of for the current
process. Store at most MAXCOUNT group IDs in the GROUPLIST array.
If GID is not -1, store it first (if possible). GID should be the
group ID (pw_gid) obtained from getpwuid, in case USERNAME is not
listed in /etc/groups. Upon failure, set errno and return -1.
Otherwise, return the number of IDs we've written into GROUPLIST. */
int
getugroups (int maxcount, GETGROUPS_T *grouplist, char const *username,
gid_t gid)
{
int count = 0;
if (gid != (gid_t) -1)
{
if (maxcount != 0)
grouplist[count] = gid;
++count;
}
setgrent ();
while (1)
{
char **cp;
struct group *grp;
errno = 0;
grp = getgrent ();
if (grp == NULL)
break;
for (cp = grp->gr_mem; *cp; ++cp)
{
int n;
if ( ! STREQ (username, *cp))
continue;
/* See if this group number is already on the list. */
for (n = 0; n < count; ++n)
if (grouplist && grouplist[n] == grp->gr_gid)
break;
/* If it's a new group number, then try to add it to the list. */
if (n == count)
{
if (maxcount != 0)
{
if (count >= maxcount)
goto done;
grouplist[count] = grp->gr_gid;
}
if (count == INT_MAX)
{
errno = EOVERFLOW;
goto done;
}
count++;
}
}
}
if (errno != 0)
count = -1;
done:
{
int saved_errno = errno;
endgrent ();
errno = saved_errno;
}
return count;
}
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