bin/pax/pwcache.c

   1 /*      $OpenBSD: pwcache.c,v 1.13 2015/11/25 23:16:01 jcs Exp $ */
   2 /*
   3  * Copyright (c) 1989, 1993
   4  *      The Regents of the University of California.  All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. Neither the name of the University nor the names of its contributors
  15  *    may be used to endorse or promote products derived from this software
  16  *    without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  */
  30
  31 #include <sys/types.h>
  32
  33 #include <grp.h>
  34 #include <pwd.h>
  35 #include <stdio.h>
  36 #include <string.h>
  37
  38 #include "compat.h"
  39
  40 #define NCACHE  16                      /* power of 2 */
  41 #define NLINES  4                       /* associativity */
  42 #define MASK    (NCACHE - 1)            /* bits to store with */
  43 #define IDX(x, i)       ((x & MASK) + i * NCACHE)
  44
  45 char *
  46 user_from_uid(uid_t uid, int nouser)
  47 {
  48         static struct ncache {
  49                 uid_t   uid;
  50                 short   noname;
  51                 char    name[_PW_NAME_LEN + 1];
  52         } c_uid[NLINES * NCACHE];
  53         char pwbuf[_PW_BUF_LEN];
  54         struct passwd pwstore, *pw;
  55         struct ncache *cp;
  56         unsigned int i;
  57
  58         for (i = 0; i < NLINES; i++) {
  59                 cp = &c_uid[IDX(uid, i)];
  60                 if (!*cp->name) {
  61 fillit:
  62                         cp->uid = uid;
  63                         pw = NULL;
  64                         getpwuid_r(uid, &pwstore, pwbuf, sizeof(pwbuf), &pw);
  65                         if (pw == NULL) {
  66                                 snprintf(cp->name, sizeof(cp->name), "%u", uid);
  67                                 cp->noname = 1;
  68                         } else {
  69                                 strlcpy(cp->name, pw->pw_name, sizeof(cp->name));
  70                         }
  71                 }
  72                 if (cp->uid == uid) {
  73                         if (nouser && cp->noname)
  74                                 return NULL;
  75                         return cp->name;
  76                 }
  77         }
  78         /* move everybody down a slot */
  79         for (i = 0; i < NLINES - 1; i++) {
  80                 struct ncache *next;
  81
  82                 cp = &c_uid[IDX(uid, i)];
  83                 next = &c_uid[IDX(uid, i + 1)];
  84                 memcpy(next, cp, sizeof(*cp));
  85         }
  86         cp = &c_uid[IDX(uid, 0)];
  87         goto fillit;
  88 }
  89
  90 char *
  91 group_from_gid(gid_t gid, int nogroup)
  92 {
  93         static struct ncache {
  94                 gid_t   gid;
  95                 short   noname;
  96                 char    name[_PW_NAME_LEN + 1];
  97         } c_gid[NLINES * NCACHE];
  98         char grbuf[_GR_BUF_LEN];
  99         struct group grstore, *gr;
 100         struct ncache *cp;
 101         unsigned int i;
 102
 103         for (i = 0; i < NLINES; i++) {
 104                 cp = &c_gid[IDX(gid, i)];
 105                 if (!*cp->name) {
 106 fillit:
 107                         cp->gid = gid;
 108                         gr = NULL;
 109                         getgrgid_r(gid, &grstore, grbuf, sizeof(grbuf), &gr);
 110                         if (gr == NULL) {
 111                                 snprintf(cp->name, sizeof(cp->name), "%u", gid);
 112                                 cp->noname = 1;
 113                         } else {
 114                                 strlcpy(cp->name, gr->gr_name, sizeof(cp->name));
 115                         }
 116                 }
 117                 if (cp->gid == gid) {
 118                         if (nogroup && cp->noname)
 119                                 return NULL;
 120                         return cp->name;
 121                 }
 122         }
 123         /* move everybody down a slot */
 124         for (i = 0; i < NLINES - 1; i++) {
 125                 struct ncache *next;
 126
 127                 cp = &c_gid[IDX(gid, i)];
 128                 next = &c_gid[IDX(gid, i + 1)];
 129                 memcpy(next, cp, sizeof(*cp));
 130         }
 131         cp = &c_gid[IDX(gid, 0)];
 132         goto fillit;
 133 }