1 /* Provide a working getlogin_r for systems which lack it.
2
3 Copyright (C) 2005 Free Software Foundation, Inc.
4
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2, or (at your option)
8 any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software Foundation,
17 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
18
19 /* written by Paul Eggert and Derek Price */
20
21 #ifdef HAVE_CONFIG_H
22 # include <config.h>
23 #endif
24
25 #include "getlogin_r.h"
26
27 #include <errno.h>
28 #include <string.h>
29
30 #if HAVE_UNISTD_H
31 # include <unistd.h>
32 #endif
33
34 #if !HAVE_DECL_GETLOGIN
35 char *getlogin (void);
36 #endif
37
38 /* See getlogin_r.h for documentation. */
39 int
getlogin_r(char * name,size_t size)40 getlogin_r (char *name, size_t size)
41 {
42 char *n;
43 size_t nlen;
44
45 errno = 0;
46 n = getlogin ();
47
48 /* A system function like getlogin_r is never supposed to set errno
49 to zero, so make sure errno is nonzero here. ENOENT is a
50 reasonable errno value if getlogin returns NULL. */
51 if (!errno)
52 errno = ENOENT;
53
54 if (!n)
55 return errno;
56 nlen = strlen (n);
57 if (size <= nlen)
58 return ERANGE;
59 memcpy (name, n, nlen + 1);
60 return 0;
61 }
62