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/* Add gids implied by a user
Copyright (C) 1997, 2001, 2014 Free Software Foundation, Inc.
Written by Miles Bader <miles@gnu.ai.mit.edu>
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 2, 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, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include <stdlib.h>
#include <errno.h>
#include <idvec.h>
#include <pwd.h>
#include <grp.h>
#define NUM_STATIC_GIDS 100 /* Initial size of static gid array. */
/* The set of gids implied by a uid. */
struct uid_implies
{
uid_t uid; /* this uid... */
struct idvec *implies; /* implies these gids. */
struct uid_implies *next;
};
/* Cache of previously calculated results for add_implied_gids. */
static struct uid_implies *uid_implies_cache = 0;
/* Add to IMPLIED_GIDS those group ids implied by the user UID. */
static error_t
_merge_implied_gids (struct idvec *implied_gids, uid_t uid)
{
struct uid_implies *ui;
for (ui = uid_implies_cache; ui; ui = ui->next)
if (ui->uid == uid)
return idvec_merge (implied_gids, ui->implies);
{
error_t err = 0;
struct passwd *pw = getpwuid (uid);
if (! pw)
err = EINVAL;
else
{
struct idvec *cache = make_idvec ();
gid_t _gids[NUM_STATIC_GIDS], *gids = _gids;
int maxgids = NUM_STATIC_GIDS;
int ngids = getgrouplist (pw->pw_name, pw->pw_gid, gids, &maxgids);
if (ngids == -1)
{
gids = malloc (maxgids * sizeof (gid_t));
if (! gids)
err = ENOMEM;
else
ngids = getgrouplist (pw->pw_name, pw->pw_gid, gids, &maxgids);
}
if (! cache)
err = ENOMEM;
if (! err)
{
err = idvec_merge_ids (cache, gids, ngids);
if (gids != _gids)
free (gids);
}
if (! err)
{
idvec_merge (implied_gids, cache);
ui = malloc (sizeof (struct uid_implies));
if (ui)
{
ui->uid = uid;
ui->implies = cache;
ui->next = uid_implies_cache;
uid_implies_cache = ui;
}
else
idvec_free (cache);
}
}
return err;
}
}
/* Add to GIDS those group ids implied by the users in UIDS. */
error_t
idvec_merge_implied_gids (struct idvec *gids, const struct idvec *uids)
{
unsigned int i;
error_t err = 0;
for (i = 0; i < uids->num; i++)
{
error_t this_err = _merge_implied_gids (gids, uids->ids[i]);
if (this_err && !err)
err = this_err;
}
return err;
}
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