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pwcache.c revision 1.7 
      1 /*	$NetBSD: pwcache.c,v 1.7 1997/07/13 19:17:13 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1989, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #if defined(LIBC_SCCS) && !defined(lint)
     38 #if 0
     39 static char sccsid[] = "@(#)pwcache.c	8.1 (Berkeley) 6/4/93";
     40 #else
     41 __RCSID("$NetBSD: pwcache.c,v 1.7 1997/07/13 19:17:13 christos Exp $");
     42 #endif
     43 #endif /* LIBC_SCCS and not lint */
     44 
     45 #include <sys/types.h>
     46 #include <sys/param.h>
     47 
     48 #include <grp.h>
     49 #include <pwd.h>
     50 #include <stdio.h>
     51 #include <string.h>
     52 #include <utmp.h>
     53 
     54 #define	NCACHE	64			/* power of 2 */
     55 #define	MASK	(NCACHE - 1)		/* bits to store with */
     56 
     57 char *
     58 user_from_uid(uid, nouser)
     59 	uid_t uid;
     60 	int nouser;
     61 {
     62 	static struct ncache {
     63 		uid_t	uid;
     64 		char	name[MAXLOGNAME + 1];
     65 	} c_uid[NCACHE];
     66 	static int pwopen;
     67 	static char nbuf[15];		/* 32 bits == 10 digits */
     68 	register struct passwd *pw;
     69 	register struct ncache *cp;
     70 
     71 	cp = c_uid + (uid & MASK);
     72 	if (cp->uid != uid || !*cp->name) {
     73 		if (pwopen == 0) {
     74 			setpassent(1);
     75 			pwopen = 1;
     76 		}
     77 		if ((pw = getpwuid(uid)) == NULL) {
     78 			if (nouser)
     79 				return (NULL);
     80 			(void)snprintf(nbuf, sizeof(nbuf), "%u", uid);
     81 			return (nbuf);
     82 		}
     83 		cp->uid = uid;
     84 		(void)strncpy(cp->name, pw->pw_name, MAXLOGNAME);
     85 		cp->name[MAXLOGNAME] = '\0';
     86 	}
     87 	return (cp->name);
     88 }
     89 
     90 char *
     91 group_from_gid(gid, nogroup)
     92 	gid_t gid;
     93 	int nogroup;
     94 {
     95 	static struct ncache {
     96 		gid_t	gid;
     97 		char	name[MAXLOGNAME + 1];
     98 	} c_gid[NCACHE];
     99 	static int gropen;
    100 	static char nbuf[15];		/* 32 bits == 10 digits */
    101 	struct group *gr;
    102 	struct ncache *cp;
    103 
    104 	cp = c_gid + (gid & MASK);
    105 	if (cp->gid != gid || !*cp->name) {
    106 		if (gropen == 0) {
    107 			setgroupent(1);
    108 			gropen = 1;
    109 		}
    110 		if ((gr = getgrgid(gid)) == NULL) {
    111 			if (nogroup)
    112 				return (NULL);
    113 			(void)snprintf(nbuf, sizeof(nbuf), "%u", gid);
    114 			return (nbuf);
    115 		}
    116 		cp->gid = gid;
    117 		(void)strncpy(cp->name, gr->gr_name, MAXLOGNAME);
    118 		cp->name[MAXLOGNAME] = '\0';
    119 	}
    120 	return (cp->name);
    121 }
    122