1// Copyright 2016 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5// +build dragonfly freebsd !android,linux netbsd openbsd
6// +build cgo,!osusergo
7
8package user
9
10/*
11#include <unistd.h>
12#include <sys/types.h>
13#include <grp.h>
14
15static int mygetgrouplist(const char* user, gid_t group, gid_t* groups, int* ngroups) {
16	return getgrouplist(user, group, groups, ngroups);
17}
18*/
19import "C"
20import (
21	"fmt"
22	"unsafe"
23)
24
25func getGroupList(name *C.char, userGID C.gid_t, gids *C.gid_t, n *C.int) C.int {
26	return C.mygetgrouplist(name, userGID, gids, n)
27}
28
29// groupRetry retries getGroupList with much larger size for n. The result is
30// stored in gids.
31func groupRetry(username string, name []byte, userGID C.gid_t, gids *[]C.gid_t, n *C.int) error {
32	// More than initial buffer, but now n contains the correct size.
33	if *n > maxGroups {
34		return fmt.Errorf("user: %q is a member of more than %d groups", username, maxGroups)
35	}
36	*gids = make([]C.gid_t, *n)
37	rv := getGroupList((*C.char)(unsafe.Pointer(&name[0])), userGID, &(*gids)[0], n)
38	if rv == -1 {
39		return fmt.Errorf("user: list groups for %s failed", username)
40	}
41	return nil
42}
43