xref: /openbsd-src/lib/libc/gen/pwcache.c (revision b2ea75c1b17e1a9a339660e7ed45cd24946b230e)
1 /*
2  * Copyright (c) 1989, 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. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #if defined(LIBC_SCCS) && !defined(lint)
35 static char rcsid[] = "$OpenBSD: pwcache.c,v 1.5 2001/06/27 00:58:54 lebel Exp $";
36 #endif /* LIBC_SCCS and not lint */
37 
38 #include <sys/types.h>
39 
40 #include <grp.h>
41 #include <pwd.h>
42 #include <stdio.h>
43 #include <string.h>
44 
45 #define	NCACHE	64			/* power of 2 */
46 #define	MASK	(NCACHE - 1)		/* bits to store with */
47 
48 char *
49 user_from_uid(uid, nouser)
50 	uid_t uid;
51 	int nouser;
52 {
53 	static struct ncache {
54 		uid_t	uid;
55 		char	name[_PW_NAME_LEN + 1];
56 	} c_uid[NCACHE];
57 	static int pwopen;
58 	static char nbuf[15];		/* 32 bits == 10 digits */
59 	register struct passwd *pw;
60 	register struct ncache *cp;
61 
62 	cp = c_uid + (uid & MASK);
63 	if (cp->uid != uid || !*cp->name) {
64 		if (pwopen == 0) {
65 			setpassent(1);
66 			pwopen = 1;
67 		}
68 		if ((pw = getpwuid(uid)) == NULL) {
69 			if (nouser)
70 				return (NULL);
71 			(void)snprintf(nbuf, sizeof(nbuf), "%u", uid);
72 			return (nbuf);
73 		}
74 		cp->uid = uid;
75 		strlcpy(cp->name, pw->pw_name, sizeof(cp->name));
76 	}
77 	return (cp->name);
78 }
79 
80 char *
81 group_from_gid(gid, nogroup)
82 	gid_t gid;
83 	int nogroup;
84 {
85 	static struct ncache {
86 		gid_t	gid;
87 		char	name[_PW_NAME_LEN + 1];
88 	} c_gid[NCACHE];
89 	static int gropen;
90 	static char nbuf[15];		/* 32 bits == 10 digits */
91 	struct group *gr;
92 	struct ncache *cp;
93 
94 	cp = c_gid + (gid & MASK);
95 	if (cp->gid != gid || !*cp->name) {
96 		if (gropen == 0) {
97 			setgroupent(1);
98 			gropen = 1;
99 		}
100 		if ((gr = getgrgid(gid)) == NULL) {
101 			if (nogroup)
102 				return (NULL);
103 			(void)snprintf(nbuf, sizeof(nbuf), "%u", gid);
104 			return (nbuf);
105 		}
106 		cp->gid = gid;
107 		strlcpy(cp->name, gr->gr_name, sizeof(cp->name));
108 	}
109 	return (cp->name);
110 }
111