58 lines
1.5 KiB
Go
58 lines
1.5 KiB
Go
// Copyright 2016 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build dragonfly darwin freebsd !android,linux netbsd openbsd
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package user
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import (
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"fmt"
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"strconv"
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"syscall"
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)
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/*
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#include <unistd.h>
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#include <sys/types.h>
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#include <stdlib.h>
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*/
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func listGroups(u *User) ([]string, error) {
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ug, err := strconv.Atoi(u.Gid)
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if err != nil {
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return nil, fmt.Errorf("user: list groups for %s: invalid gid %q", u.Username, u.Gid)
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}
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userGID := syscall.Gid_t(ug)
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nameC, err := syscall.BytePtrFromString(u.Username)
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if err != nil {
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return nil, fmt.Errorf("user: invalid user name %q: %v", strconv.Quote(u.Username), err)
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}
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n := int32(256)
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gidsC := make([]syscall.Gid_t, n)
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syscall.Entersyscall()
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rv := libc_getgrouplist(nameC, userGID, &gidsC[0], &n)
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syscall.Exitsyscall()
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if rv == -1 {
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// More than initial buffer, but now n contains the correct size.
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const maxGroups = 2048
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if n > maxGroups {
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return nil, fmt.Errorf("user: list groups for %s: member of more than %d groups", u.Username, maxGroups)
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}
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gidsC = make([]syscall.Gid_t, n)
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syscall.Entersyscall()
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rv := libc_getgrouplist(nameC, userGID, &gidsC[0], &n)
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syscall.Exitsyscall()
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if rv == -1 {
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return nil, fmt.Errorf("user: list groups for %s failed (changed groups?)", u.Username)
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}
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}
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gidsC = gidsC[:n]
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gids := make([]string, 0, n)
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for _, g := range gidsC[:n] {
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gids = append(gids, strconv.Itoa(int(g)))
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}
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return gids, nil
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}
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