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  * $DragonFly: src/lib/libc/gen/pwcache.c,v 1.5 2005/11/13 00:07:42 swildner Exp $
  35  */
  36
  37 #include <grp.h>
  38 #include <pwd.h>
  39 #include <stdlib.h>
  40 #include <stdio.h>
  41 #include <string.h>
  42 #include <utmp.h>
  43
  44 #define NCACHE  64                      /* power of 2 */
  45 #define MASK    (NCACHE - 1)            /* bits to store with */
  46
  47 char *
  48 user_from_uid(uid_t uid, int nouser)
  49 {
  50         static struct ncache {
  51                 uid_t   uid;
  52                 int     found;
  53                 char    name[UT_NAMESIZE + 1];
  54         } c_uid[NCACHE];
  55         static int pwopen;
  56         struct passwd *pw;
  57         struct ncache *cp;
  58
  59         cp = c_uid + (uid & MASK);
  60         if (cp->uid != uid || !*cp->name) {
  61                 if (pwopen == 0) {
  62                         setpassent(1);
  63                         pwopen = 1;
  64                 }
  65                 pw = getpwuid(uid);
  66                 cp->uid = uid;
  67                 if (pw != NULL) {
  68                         cp->found = 1;
  69                         strncpy(cp->name, pw->pw_name, UT_NAMESIZE);
  70                         cp->name[UT_NAMESIZE] = '\0';
  71                 } else {
  72                         cp->found = 0;
  73                         snprintf(cp->name, UT_NAMESIZE, "%u", uid);
  74                         if (nouser)
  75                                 return (NULL);
  76                 }
  77         }
  78         return ((nouser && !cp->found) ? NULL : cp->name);
  79 }
  80
  81 char *
  82 group_from_gid(gid_t gid, int nogroup)
  83 {
  84         static struct ncache {
  85                 gid_t   gid;
  86                 int     found;
  87                 char    name[UT_NAMESIZE + 1];
  88         } c_gid[NCACHE];
  89         static int gropen;
  90         struct group *gr;
  91         struct ncache *cp;
  92
  93         cp = c_gid + (gid & MASK);
  94         if (cp->gid != gid || !*cp->name) {
  95                 if (gropen == 0) {
  96                         setgroupent(1);
  97                         gropen = 1;
  98                 }
  99                 gr = getgrgid(gid);
 100                 cp->gid = gid;
 101                 if (gr != NULL) {
 102                         cp->found = 1;
 103                         strncpy(cp->name, gr->gr_name, UT_NAMESIZE);
 104                         cp->name[UT_NAMESIZE] = '\0';
 105                 } else {
 106                         cp->found = 0;
 107                         snprintf(cp->name, UT_NAMESIZE, "%u", gid);
 108                         if (nogroup)
 109                                 return (NULL);
 110                 }
 111         }
 112         return ((nogroup && !cp->found) ? NULL : cp->name);
 113 }