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samba-mirror/source3/lib/system_smbd.c
Andrew Bartlett 8690b271a6 Move tridge's getgrouplist() replacement function from replace.c to a new
'system_smbd.c' file, where it can link with become_root() and unbecome_root(),
and therefore avoiding some nasty 'it workes on linux' bugs.

(The replacement function is implemented in terms of initgroups(), which is
naturally only avaliable to root).

Andrew Bartlett
(This used to be commit a91018dd02)
2002-08-17 07:09:22 +00:00

106 lines
2.7 KiB
C

/*
Unix SMB/CIFS implementation.
system call wrapper interface.
Copyright (C) Andrew Tridgell 2002
Copyright (C) Andrew Barteltt 2002
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 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, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
This file may assume linkage with smbd - for things like become_root()
etc.
*/
#include "includes.h"
#ifndef HAVE_GETGROUPLIST
/*
This is a *much* faster way of getting the list of groups for a user
without changing the current supplemenrary group list. The old
method used getgrent() which could take 20 minutes on a really big
network with hundeds of thousands of groups and users. The new method
takes a couple of seconds.
NOTE!! this function only works if it is called as root!
*/
static int getgrouplist_internals(const char *user, gid_t gid, gid_t *groups, int *grpcnt)
{
gid_t *gids_saved;
int ret, ngrp_saved;
/* work out how many groups we need to save */
ngrp_saved = getgroups(0, NULL);
if (ngrp_saved == -1) {
/* this shouldn't happen */
return -1;
}
gids_saved = (gid_t *)malloc(sizeof(gid_t) * (ngrp_saved+1));
if (!gids_saved) {
errno = ENOMEM;
return -1;
}
ngrp_saved = getgroups(ngrp_saved, gids_saved);
if (ngrp_saved == -1) {
free(gids_saved);
/* very strange! */
return -1;
}
if (initgroups(user, gid) != 0) {
free(gids_saved);
return -1;
}
/* this must be done to cope with systems that put the current egid in the
return from getgroups() */
save_re_gid();
set_effective_gid(gid);
setgid(gid);
ret = getgroups(*grpcnt, groups);
if (ret >= 0) {
*grpcnt = ret;
}
restore_re_gid();
if (setgroups(ngrp_saved, gids_saved) != 0) {
/* yikes! */
DEBUG(0,("ERROR: getgrouplist: failed to reset group list!\n"));
smb_panic("getgrouplist: failed to reset group list!\n");
free(gids_saved);
return -1;
}
free(gids_saved);
return ret;
}
#endif
int sys_getgrouplist(const char *user, gid_t gid, gid_t *groups, int *grpcnt)
{
#ifdef HAVE_GETGROUPLIST
return getgrouplist(user, gid, groups, grpcnt);
#else
int retval;
become_root();
retval = getgrouplist_internals(user, gid, groups, grpcnt);
unbecome_root();
#endif
}