121 lines
3.0 KiB
Go
121 lines
3.0 KiB
Go
// Copyright 2011 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 darwin freebsd linux netbsd
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// +build cgo
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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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"strings"
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"syscall"
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"unsafe"
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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 <pwd.h>
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#include <stdlib.h>
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static int mygetpwuid_r(int uid, struct passwd *pwd,
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char *buf, size_t buflen, struct passwd **result) {
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return getpwuid_r(uid, pwd, buf, buflen, result);
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}
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*/
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//extern getpwnam_r
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func libc_getpwnam_r(name *byte, pwd *syscall.Passwd, buf *byte, buflen syscall.Size_t, result **syscall.Passwd) int
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//extern getpwuid_r
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func libc_getpwuid_r(uid syscall.Uid_t, pwd *syscall.Passwd, buf *byte, buflen syscall.Size_t, result **syscall.Passwd) int
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// bytePtrToString takes a NUL-terminated array of bytes and convert
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// it to a Go string.
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func bytePtrToString(p *byte) string {
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a := (*[10000]byte)(unsafe.Pointer(p))
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i := 0
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for a[i] != 0 {
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i++
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}
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return string(a[:i])
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}
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// Current returns the current user.
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func Current() (*User, error) {
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return lookup(syscall.Getuid(), "", false)
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}
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// Lookup looks up a user by username. If the user cannot be found,
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// the returned error is of type UnknownUserError.
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func Lookup(username string) (*User, error) {
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return lookup(-1, username, true)
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}
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// LookupId looks up a user by userid. If the user cannot be found,
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// the returned error is of type UnknownUserIdError.
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func LookupId(uid string) (*User, error) {
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i, e := strconv.Atoi(uid)
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if e != nil {
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return nil, e
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}
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return lookup(i, "", false)
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}
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func lookup(uid int, username string, lookupByName bool) (*User, error) {
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var pwd syscall.Passwd
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var result *syscall.Passwd
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// FIXME: Should let buf grow if necessary.
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const bufSize = 1024
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buf := make([]byte, bufSize)
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if lookupByName {
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p := syscall.StringBytePtr(username)
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syscall.Entersyscall()
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rv := libc_getpwnam_r(p,
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&pwd,
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&buf[0],
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bufSize,
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&result)
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syscall.Exitsyscall()
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if rv != 0 {
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return nil, fmt.Errorf("user: lookup username %s: %s", username, syscall.GetErrno())
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}
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if result == nil {
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return nil, UnknownUserError(username)
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}
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} else {
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syscall.Entersyscall()
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rv := libc_getpwuid_r(syscall.Uid_t(uid),
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&pwd,
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&buf[0],
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bufSize,
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&result)
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syscall.Exitsyscall()
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if rv != 0 {
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return nil, fmt.Errorf("user: lookup userid %d: %s", uid, syscall.GetErrno())
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}
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if result == nil {
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return nil, UnknownUserIdError(uid)
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}
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}
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u := &User{
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Uid: strconv.Itoa(int(pwd.Pw_uid)),
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Gid: strconv.Itoa(int(pwd.Pw_gid)),
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Username: bytePtrToString((*byte)(unsafe.Pointer(pwd.Pw_name))),
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Name: bytePtrToString((*byte)(unsafe.Pointer(pwd.Pw_gecos))),
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HomeDir: bytePtrToString((*byte)(unsafe.Pointer(pwd.Pw_dir))),
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}
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// The pw_gecos field isn't quite standardized. Some docs
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// say: "It is expected to be a comma separated list of
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// personal data where the first item is the full name of the
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// user."
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if i := strings.Index(u.Name, ","); i >= 0 {
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u.Name = u.Name[:i]
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}
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return u, nil
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}
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