xref: /csrg-svn/lib/libc/gen/pwcache.c (revision 40478)
1 /*
2  * Copyright (c) 1989 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[] = "@(#)pwcache.c	5.3 (Berkeley) 03/13/90";
20 #endif /* LIBC_SCCS and not lint */
21 
22 #include <sys/types.h>
23 #include <utmp.h>
24 #include <pwd.h>
25 #include <grp.h>
26 #include <stdio.h>
27 
28 #define	NCACHE	64			/* power of 2 */
29 #define	MASK	NCACHE - 1		/* bits to store with */
30 
31 static	int pwopen = 0;
32 static	int gropen = 0;
33 
34 char *
35 user_from_uid(uid, nouser)
36 	uid_t uid;
37 	int nouser;
38 {
39 	static struct ncache {
40 		uid_t	uid;
41 		char	name[UT_NAMESIZE + 1];
42 	} c_uid[NCACHE];
43 	static char nbuf[15];		/* 32 bits == 10 digits */
44 	register struct passwd *pw;
45 	register struct ncache *cp;
46 
47 	cp = c_uid + (uid & MASK);
48 	if (cp->uid != uid || !*cp->name) {
49 		if (pwopen == 0) {
50 			setpassent(1);
51 			pwopen++;
52 		}
53 		if (!(pw = getpwuid(uid))) {
54 			if (nouser)
55 				return((char *)NULL);
56 			(void)sprintf(nbuf, "%u", uid);
57 			return(nbuf);
58 		}
59 		cp->uid = uid;
60 		(void)strncpy(cp->name, pw->pw_name, UT_NAMESIZE);
61 		cp->name[UT_NAMESIZE] = '\0';
62 	}
63 	return(cp->name);
64 }
65 
66 char *
67 group_from_gid(gid, nogroup)
68 	gid_t gid;
69 	int nogroup;
70 {
71 	static struct ncache {
72 		gid_t	gid;
73 		char	name[UT_NAMESIZE];
74 	} c_gid[NCACHE];
75 	static char nbuf[15];		/* 32 bits == 10 digits */
76 	register struct group *gr;
77 	register struct ncache *cp;
78 
79 	cp = c_gid + (gid & MASK);
80 	if (cp->gid != gid || !*cp->name) {
81 		if (gropen == 0) {
82 			setgroupent(1);
83 			gropen++;
84 		}
85 		if (!(gr = getgrgid(gid))) {
86 			if (nogroup)
87 				return((char *)NULL);
88 			(void)sprintf(nbuf, "%u", gid);
89 			return(nbuf);
90 		}
91 		cp->gid = gid;
92 		(void)strncpy(cp->name, gr->gr_name, UT_NAMESIZE);
93 		cp->name[UT_NAMESIZE] = '\0';
94 	}
95 	return(cp->name);
96 }
97