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 darwin freebsd !android,linux netbsd openbsd 6 7 package user 8 9 import ( 10 "fmt" 11 "strconv" 12 "unsafe" 13 ) 14 15 /* 16 #include <unistd.h> 17 #include <sys/types.h> 18 #include <stdlib.h> 19 */ 20 import "C" 21 22 func listGroups(u *User) ([]string, error) { 23 ug, err := strconv.Atoi(u.Gid) 24 if err != nil { 25 return nil, fmt.Errorf("user: list groups for %s: invalid gid %q", u.Username, u.Gid) 26 } 27 userGID := C.gid_t(ug) 28 nameC := C.CString(u.Username) 29 defer C.free(unsafe.Pointer(nameC)) 30 31 n := C.int(256) 32 gidsC := make([]C.gid_t, n) 33 rv := getGroupList(nameC, userGID, &gidsC[0], &n) 34 if rv == -1 { 35 // More than initial buffer, but now n contains the correct size. 36 const maxGroups = 2048 37 if n > maxGroups { 38 return nil, fmt.Errorf("user: list groups for %s: member of more than %d groups", u.Username, maxGroups) 39 } 40 gidsC = make([]C.gid_t, n) 41 rv := getGroupList(nameC, userGID, &gidsC[0], &n) 42 if rv == -1 { 43 return nil, fmt.Errorf("user: list groups for %s failed (changed groups?)", u.Username) 44 } 45 } 46 gidsC = gidsC[:n] 47 gids := make([]string, 0, n) 48 for _, g := range gidsC[:n] { 49 gids = append(gids, strconv.Itoa(int(g))) 50 } 51 return gids, nil 52 } 53
