getlogin.c revision 1.9 
1/*
2 * Copyright (c) 1988, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#if defined(LIBC_SCCS) && !defined(lint)
31static char rcsid[] = "$OpenBSD: getlogin.c,v 1.9 2003/06/11 21:03:10 deraadt Exp $";
32#endif /* LIBC_SCCS and not lint */
33
34#include <sys/param.h>
35#include <pwd.h>
36#include <utmp.h>
37#include <stdio.h>
38#include <string.h>
39#include <unistd.h>
40#include <errno.h>
41#include "thread_private.h"
42
43_THREAD_PRIVATE_MUTEX(logname);
44static int  logname_valid = 0;
45static char logname[MAXLOGNAME + 1];
46
47int	_getlogin(char *, size_t);
48int	_setlogin(const char *);
49
50char *
51getlogin(void)
52{
53	_THREAD_PRIVATE_KEY(getlogin);
54	char * name = (char *)_THREAD_PRIVATE(getlogin, logname, NULL);
55
56	if ((errno = getlogin_r(name, sizeof logname)) != 0)
57		return NULL;
58	if (*name == '\0') {
59		errno = ENOENT;  /* well? */
60		return NULL;
61	}
62	return name;
63}
64
65int
66getlogin_r(char *name, size_t namelen)
67{
68	int logname_size;
69
70	if (name == NULL)
71		return EFAULT;
72
73	_THREAD_PRIVATE_MUTEX_LOCK(logname);
74	if (!logname_valid) {
75		if (_getlogin(logname, sizeof(logname) - 1) < 0) {
76			_THREAD_PRIVATE_MUTEX_UNLOCK(logname);
77			return errno;
78		}
79		logname_valid = 1;
80		logname[MAXLOGNAME] = '\0';	/* paranoia */
81	}
82	logname_size = strlen(logname) + 1;
83	if (namelen < logname_size) {
84		_THREAD_PRIVATE_MUTEX_UNLOCK(logname);
85		return ERANGE;
86	}
87	memcpy(name, logname, logname_size);
88	_THREAD_PRIVATE_MUTEX_UNLOCK(logname);
89	return 0;
90}
91
92int
93setlogin(const char *name)
94{
95	int ret;
96
97	_THREAD_PRIVATE_MUTEX_LOCK(logname);
98	ret = _setlogin(name);
99	if (ret == 0)
100		logname_valid = 0;
101	_THREAD_PRIVATE_MUTEX_UNLOCK(logname);
102	return ret;
103}
104