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 #define NCACHE 16 /* power of 2 */ 39 #define NLINES 4 /* associativity */ 40 #define MASK (NCACHE - 1) /* bits to store with */ 41 #define IDX(x, i) ((x & MASK) + i * NCACHE) 42 43 char * 44 user_from_uid(uid_t uid, int nouser) 45 { 46 static struct ncache { 47 uid_t uid; 48 short noname; 49 char name[_PW_NAME_LEN + 1]; 50 } c_uid[NLINES * NCACHE]; 51 char pwbuf[_PW_BUF_LEN]; 52 struct passwd pwstore, *pw; 53 struct ncache *cp; 54 unsigned int i; 55 56 for (i = 0; i < NLINES; i++) { 57 cp = &c_uid[IDX(uid, i)]; 58 if (!*cp->name) { 59 fillit: 60 cp->uid = uid; 61 pw = NULL; 62 getpwuid_r(uid, &pwstore, pwbuf, sizeof(pwbuf), &pw); 63 if (pw == NULL) { 64 snprintf(cp->name, sizeof(cp->name), "%u", uid); 65 cp->noname = 1; 66 } else { 67 strlcpy(cp->name, pw->pw_name, sizeof(cp->name)); 68 } 69 } 70 if (cp->uid == uid) { 71 if (nouser && cp->noname) 72 return NULL; 73 return cp->name; 74 } 75 } 76 /* move everybody down a slot */ 77 for (i = 0; i < NLINES - 1; i++) { 78 struct ncache *next; 79 80 cp = &c_uid[IDX(uid, i)]; 81 next = &c_uid[IDX(uid, i + 1)]; 82 memcpy(next, cp, sizeof(*cp)); 83 } 84 cp = &c_uid[IDX(uid, 0)]; 85 goto fillit; 86 } 87 88 char * 89 group_from_gid(gid_t gid, int nogroup) 90 { 91 static struct ncache { 92 gid_t gid; 93 short noname; 94 char name[_PW_NAME_LEN + 1]; 95 } c_gid[NLINES * NCACHE]; 96 char grbuf[_GR_BUF_LEN]; 97 struct group grstore, *gr; 98 struct ncache *cp; 99 unsigned int i; 100 101 for (i = 0; i < NLINES; i++) { 102 cp = &c_gid[IDX(gid, i)]; 103 if (!*cp->name) { 104 fillit: 105 cp->gid = gid; 106 gr = NULL; 107 getgrgid_r(gid, &grstore, grbuf, sizeof(grbuf), &gr); 108 if (gr == NULL) { 109 snprintf(cp->name, sizeof(cp->name), "%u", gid); 110 cp->noname = 1; 111 } else { 112 strlcpy(cp->name, gr->gr_name, sizeof(cp->name)); 113 } 114 } 115 if (cp->gid == gid) { 116 if (nogroup && cp->noname) 117 return NULL; 118 return cp->name; 119 } 120 } 121 /* move everybody down a slot */ 122 for (i = 0; i < NLINES - 1; i++) { 123 struct ncache *next; 124 125 cp = &c_gid[IDX(gid, i)]; 126 next = &c_gid[IDX(gid, i + 1)]; 127 memcpy(next, cp, sizeof(*cp)); 128 } 129 cp = &c_gid[IDX(gid, 0)]; 130 goto fillit; 131 } 132