lib/libc/gen/pwcache.c

   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  * @(#)pwcache.c        8.1 (Berkeley) 6/4/93
  34  * $FreeBSD: src/lib/libc/gen/pwcache.c,v 1.10 2002/03/22 02:35:47 imp Exp $
  35  * $DragonFly: src/lib/libc/gen/pwcache.c,v 1.5 2005/11/13 00:07:42 swildner Exp $
  36  */
  37
  38 #include <sys/types.h>
  39
  40 #include <grp.h>
  41 #include <pwd.h>
  42 #include <stdio.h>
  43 #include <string.h>
  44 #include <utmp.h>
  45
  46 #define NCACHE  64                      /* power of 2 */
  47 #define MASK    (NCACHE - 1)            /* bits to store with */
  48
  49 const char *
  50 user_from_uid(uid_t uid, int nouser)
  51 {
  52         static struct ncache {
  53                 uid_t   uid;
  54                 int     found;
  55                 char    name[UT_NAMESIZE + 1];
  56         } c_uid[NCACHE];
  57         static int pwopen;
  58         struct passwd *pw;
  59         struct ncache *cp;
  60
  61         cp = c_uid + (uid & MASK);
  62         if (cp->uid != uid || !*cp->name) {
  63                 if (pwopen == 0) {
  64                         setpassent(1);
  65                         pwopen = 1;
  66                 }
  67                 pw = getpwuid(uid);
  68                 cp->uid = uid;
  69                 if (pw != NULL) {
  70                         cp->found = 1;
  71                         strncpy(cp->name, pw->pw_name, UT_NAMESIZE);
  72                         cp->name[UT_NAMESIZE] = '\0';
  73                 } else {
  74                         cp->found = 0;
  75                         snprintf(cp->name, UT_NAMESIZE, "%u", uid);
  76                         if (nouser)
  77                                 return (NULL);
  78                 }
  79         }
  80         return ((nouser && !cp->found) ? NULL : cp->name);
  81 }
  82
  83 const char *
  84 group_from_gid(gid_t gid, int nogroup)
  85 {
  86         static struct ncache {
  87                 gid_t   gid;
  88                 int     found;
  89                 char    name[UT_NAMESIZE + 1];
  90         } c_gid[NCACHE];
  91         static int gropen;
  92         struct group *gr;
  93         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 = 1;
 100                 }
 101                 gr = getgrgid(gid);
 102                 cp->gid = gid;
 103                 if (gr != NULL) {
 104                         cp->found = 1;
 105                         strncpy(cp->name, gr->gr_name, UT_NAMESIZE);
 106                         cp->name[UT_NAMESIZE] = '\0';
 107                 } else {
 108                         cp->found = 0;
 109                         snprintf(cp->name, UT_NAMESIZE, "%u", gid);
 110                         if (nogroup)
 111                                 return (NULL);
 112                 }
 113         }
 114         return ((nogroup && !cp->found) ? NULL : cp->name);
 115 }