1 files changed, 119 insertions, 0 deletions
diff --git a/source4/lib/system_smbd.c b/source4/lib/system_smbd.c
new file mode 100644
index 0000000000..3ae0a6395e
--- /dev/null
+++ b/source4/lib/system_smbd.c
@@ -0,0 +1,119 @@
+/* 
+   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, num_gids;
+
+	if (non_root_mode()) {
+		*grpcnt = 0;
+		return 0;
+	}
+
+	/* 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) {
+		SAFE_FREE(gids_saved);
+		/* very strange! */
+		return -1;
+	}
+
+	if (initgroups(user, gid) != 0) {
+		DEBUG(0, ("getgrouplist_internals: initgroups() failed!\n"));
+		SAFE_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);
+
+	num_gids = getgroups(0, NULL);
+	if (num_gids + 1 > *grpcnt) {
+		*grpcnt = num_gids + 1;
+		ret = -1;
+	} else {
+		ret = getgroups(*grpcnt - 1, &groups[1]);
+		if (ret >= 0) {
+			groups[0] = gid;
+			*grpcnt = ret + 1;
+		}
+	}
+
+	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();
+	return retval;
+#endif
+}