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pwcache.c revision 1.1 
      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, 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 sccsid[] = "@(#)pwcache.c	5.4 (Berkeley) 6/1/90";
     36 #endif /* LIBC_SCCS and not lint */
     37 
     38 #include <sys/types.h>
     39 #include <utmp.h>
     40 #include <pwd.h>
     41 #include <grp.h>
     42 #include <stdio.h>
     43 
     44 #define	NCACHE	64			/* power of 2 */
     45 #define	MASK	NCACHE - 1		/* bits to store with */
     46 
     47 static	int pwopen = 0;
     48 static	int gropen = 0;
     49 
     50 char *
     51 user_from_uid(uid, nouser)
     52 	uid_t uid;
     53 	int nouser;
     54 {
     55 	static struct ncache {
     56 		uid_t	uid;
     57 		char	name[UT_NAMESIZE + 1];
     58 	} c_uid[NCACHE];
     59 	static char nbuf[15];		/* 32 bits == 10 digits */
     60 	register struct passwd *pw;
     61 	register struct ncache *cp;
     62 
     63 	cp = c_uid + (uid & MASK);
     64 	if (cp->uid != uid || !*cp->name) {
     65 		if (pwopen == 0) {
     66 			setpassent(1);
     67 			pwopen++;
     68 		}
     69 		if (!(pw = getpwuid(uid))) {
     70 			if (nouser)
     71 				return((char *)NULL);
     72 			(void)sprintf(nbuf, "%u", uid);
     73 			return(nbuf);
     74 		}
     75 		cp->uid = uid;
     76 		(void)strncpy(cp->name, pw->pw_name, UT_NAMESIZE);
     77 		cp->name[UT_NAMESIZE] = '\0';
     78 	}
     79 	return(cp->name);
     80 }
     81 
     82 char *
     83 group_from_gid(gid, nogroup)
     84 	gid_t gid;
     85 	int nogroup;
     86 {
     87 	static struct ncache {
     88 		gid_t	gid;
     89 		char	name[UT_NAMESIZE];
     90 	} c_gid[NCACHE];
     91 	static char nbuf[15];		/* 32 bits == 10 digits */
     92 	register struct group *gr;
     93 	register struct ncache *cp;
     94 
     95 	cp = c_gid + (gid & MASK);
     96 	if (cp->gid != gid || !*cp->name) {
     97 		if (gropen == 0) {
     98 			setgroupent(1);
     99 			gropen++;
    100 		}
    101 		if (!(gr = getgrgid(gid))) {
    102 			if (nogroup)
    103 				return((char *)NULL);
    104 			(void)sprintf(nbuf, "%u", gid);
    105 			return(nbuf);
    106 		}
    107 		cp->gid = gid;
    108 		(void)strncpy(cp->name, gr->gr_name, UT_NAMESIZE);
    109 		cp->name[UT_NAMESIZE] = '\0';
    110 	}
    111 	return(cp->name);
    112 }
    113