xref: /illumos-gate/usr/src/lib/libc/port/gen/getlogin.c (revision 8e268185036f404515ce8bc575423ac390136e3f)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright (c) 2013 Gary Mills
24  *
25  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
26  * Use is subject to license terms.
27  */
28 
29 /*	Copyright (c) 1988 AT&T	*/
30 /*	  All Rights Reserved  	*/
31 
32 #pragma weak _getlogin = getloginx
33 #pragma weak _getlogin_r = getloginx_r
34 
35 #include "lint.h"
36 #include <sys/types.h>
37 #include <sys/stat.h>
38 #include <fcntl.h>
39 #include <string.h>
40 #include <stdlib.h>
41 #include <limits.h>
42 #include "utmpx.h"
43 #include <unistd.h>
44 #include <errno.h>
45 #include <thread.h>
46 #include <synch.h>
47 #include <mtlib.h>
48 #include "tsd.h"
49 
50 /* Revert the renames done in unistd.h */
51 #ifdef	__PRAGMA_REDEFINE_EXTNAME
52 #pragma	redefine_extname	getlogint	getlogin
53 #pragma	redefine_extname	getlogint_r	getlogin_r
54 #pragma	redefine_extname	__posix_getlogint_r	__posix_getlogin_r
55 #else	/* __PRAGMA_REDEFINE_EXTNAME */
56 #ifdef	getlogin
57 #undef	getlogin
58 #endif	/* getlogin */
59 #ifdef	getlogin_r
60 #undef	getlogin_r
61 #endif	/* getlogin_r */
62 #ifdef	__posix_getlogin_r
63 #undef	__posix_getlogin_r
64 #endif	/* __posix_getlogin_r */
65 #define	getlogint	getlogin
66 #define	getlogint_r	getlogin_r
67 #define	__posix_getlogint_r	__posix_getlogin_r
68 #endif	/* __PRAGMA_REDEFINE_EXTNAME */
69 extern char *getlogint(void);
70 extern char *getlogint_r(char *, int);
71 extern int __posix_getlogint_r(char *, int);
72 
73 /*
74  * Use the full length of a login name.
75  * The utmpx interface provides for a 32 character login name.
76  */
77 #define	NMAX	(sizeof (((struct utmpx *)0)->ut_user))
78 
79 /*
80  * Common function
81  */
82 static char *
83 getl_r_common(char *answer, size_t namelen, size_t maxlen)
84 {
85 	int		uf;
86 	off64_t		me;
87 	struct futmpx	ubuf;
88 
89 	if ((me = (off64_t)ttyslot()) < 0)
90 		return (NULL);
91 	if ((uf = open64(UTMPX_FILE, 0)) < 0)
92 		return (NULL);
93 	(void) lseek64(uf, me * sizeof (ubuf), SEEK_SET);
94 	if (read(uf, &ubuf, sizeof (ubuf)) != sizeof (ubuf)) {
95 		(void) close(uf);
96 		return (NULL);
97 	}
98 	(void) close(uf);
99 	if (ubuf.ut_user[0] == '\0')
100 		return (NULL);
101 
102 	/* Insufficient buffer size */
103 	if (namelen < strnlen(&ubuf.ut_user[0], maxlen)) {
104 		errno = ERANGE;
105 		return (NULL);
106 	}
107 	(void) strncpy(&answer[0], &ubuf.ut_user[0], maxlen);
108 	answer[maxlen] = '\0';
109 	return (&answer[0]);
110 }
111 
112 /*
113  * POSIX.1c Draft-6 version of the function getlogin_r.
114  * It was implemented by Solaris 2.3.
115  */
116 char *
117 getlogint_r(char *answer, int namelen)
118 {
119 	return (getl_r_common(answer, (size_t)namelen, LOGNAME_MAX_TRAD));
120 }
121 
122 /*
123  * POSIX.1c standard version of the function getlogin_r.
124  * User gets it via static getlogin_r from the header file.
125  */
126 int
127 __posix_getlogint_r(char *name, int namelen)
128 {
129 	int nerrno = 0;
130 	int oerrno = errno;
131 
132 	errno = 0;
133 	if (getl_r_common(name, (size_t)namelen, LOGNAME_MAX_TRAD) == NULL) {
134 		if (errno == 0)
135 			nerrno = EINVAL;
136 		else
137 			nerrno = errno;
138 	}
139 	errno = oerrno;
140 	return (nerrno);
141 }
142 
143 char *
144 getlogint(void)
145 {
146 	char *answer = tsdalloc(_T_LOGIN, LOGIN_NAME_MAX_TRAD, NULL);
147 
148 	if (answer == NULL)
149 		return (NULL);
150 	return (getl_r_common(answer, LOGIN_NAME_MAX_TRAD, LOGNAME_MAX_TRAD));
151 }
152 
153 /*
154  * POSIX.1c Draft-6 version of the function getlogin_r.
155  * It was implemented by Solaris 2.3.
156  * For extended login names, selected by redefine_extname in unistd.h.
157  */
158 char *
159 getloginx_r(char *answer, int namelen)
160 {
161 	return (getl_r_common(answer, (size_t)namelen, NMAX));
162 }
163 
164 /*
165  * POSIX.1c standard version of the function getlogin_r.
166  * User gets it via static getlogin_r from the header file.
167  * For extended login names, selected by redefine_extname in unistd.h.
168  */
169 int
170 __posix_getloginx_r(char *name, int namelen)
171 {
172 	int nerrno = 0;
173 	int oerrno = errno;
174 
175 	errno = 0;
176 	if (getl_r_common(name, (size_t)namelen, NMAX) == NULL) {
177 		if (errno == 0)
178 			nerrno = EINVAL;
179 		else
180 			nerrno = errno;
181 	}
182 	errno = oerrno;
183 	return (nerrno);
184 }
185 
186 /*
187  * For extended login names, selected by redefine_extname in unistd.h.
188  */
189 char *
190 getloginx(void)
191 {
192 	char *answer = tsdalloc(_T_LOGIN, LOGIN_NAME_MAX, NULL);
193 
194 	if (answer == NULL)
195 		return (NULL);
196 	return (getl_r_common(answer, LOGIN_NAME_MAX, NMAX));
197 }
198