xref: /original-bsd/lib/libc/gen/getlogin.c (revision 05dfbb6f)
1 /*
2  * Copyright (c) 1988 The Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms are permitted
6  * provided that the above copyright notice and this paragraph are
7  * duplicated in all such forms and that any documentation,
8  * advertising materials, and other materials related to such
9  * distribution and use acknowledge that the software was developed
10  * by the University of California, Berkeley.  The name of the
11  * University may not be used to endorse or promote products derived
12  * from this software without specific prior written permission.
13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16  */
17 
18 #if defined(LIBC_SCCS) && !defined(lint)
19 static char sccsid[] = "@(#)getlogin.c	5.4 (Berkeley) 03/07/89";
20 #endif /* LIBC_SCCS and not lint */
21 
22 #include <sys/types.h>
23 #include <stdio.h>
24 #include <pwd.h>
25 #include <utmp.h>
26 
27 static	char	logname[UT_NAMESIZE+1];
28 
29 char *
30 getlogin()
31 {
32 	static int notcalled = 1;
33 
34 	if (notcalled) {
35 		if(getlogname(logname, sizeof(logname) - 1) < 0)
36 			return((char *) 0);
37 		notcalled = 0;
38 	}
39 	return(logname);
40 }
41 
42 uid_t	geteuid();
43 
44 char *
45 cuserid(s)
46 	char	*s;
47 {
48 	register struct passwd *pwd;
49 
50 	if((pwd = getpwuid(geteuid())) == NULL) {
51 		if(s)
52 			*s = '\0';
53 		return(NULL);
54 	}
55 	if(s) {
56 		(void) strncpy(s, pwd->pw_name, L_cuserid);
57 		return(s);
58 	}
59 	return(pwd->pw_name);
60 }
61