archive_write_disk_set_standard_lookup.c revision 228759
1162852Sdes/*- 2162852Sdes * Copyright (c) 2003-2007 Tim Kientzle 3162852Sdes * All rights reserved. 4162852Sdes * 5162852Sdes * Redistribution and use in source and binary forms, with or without 6162852Sdes * modification, are permitted provided that the following conditions 7162852Sdes * are met: 8162852Sdes * 1. Redistributions of source code must retain the above copyright 9162852Sdes * notice, this list of conditions and the following disclaimer. 10162852Sdes * 2. Redistributions in binary form must reproduce the above copyright 11162852Sdes * notice, this list of conditions and the following disclaimer in the 12162852Sdes * documentation and/or other materials provided with the distribution. 13162852Sdes * 14162852Sdes * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR 15162852Sdes * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16162852Sdes * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17162852Sdes * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT, 18162852Sdes * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19162852Sdes * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20162852Sdes * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21162852Sdes * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22180744Sdes * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23162852Sdes * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24162852Sdes */ 25162852Sdes 26180740Sdes#include "archive_platform.h" 27180740Sdes__FBSDID("$FreeBSD: head/lib/libarchive/archive_write_disk_set_standard_lookup.c 201083 2009-12-28 02:09:57Z kientzle $"); 28180740Sdes 29162852Sdes#ifdef HAVE_SYS_TYPES_H 30162852Sdes#include <sys/types.h> 31162852Sdes#endif 32162852Sdes#ifdef HAVE_ERRNO_H 33162852Sdes#include <errno.h> 34162852Sdes#endif 35162852Sdes#ifdef HAVE_GRP_H 36162852Sdes#include <grp.h> 37162852Sdes#endif 38162852Sdes#ifdef HAVE_PWD_H 39162852Sdes#include <pwd.h> 40162852Sdes#endif 41162852Sdes#ifdef HAVE_STDLIB_H 42162852Sdes#include <stdlib.h> 43162852Sdes#endif 44162852Sdes#ifdef HAVE_STRING_H 45162852Sdes#include <string.h> 46162852Sdes#endif 47162852Sdes 48162852Sdes#include "archive.h" 49162852Sdes#include "archive_private.h" 50162852Sdes#include "archive_read_private.h" 51162852Sdes#include "archive_write_disk_private.h" 52162852Sdes 53162852Sdesstruct bucket { 54162852Sdes char *name; 55162852Sdes int hash; 56162852Sdes id_t id; 57162852Sdes}; 58162852Sdes 59180744Sdesstatic const size_t cache_size = 127; 60162852Sdesstatic unsigned int hash(const char *); 61162852Sdesstatic gid_t lookup_gid(void *, const char *uname, gid_t); 62162852Sdesstatic uid_t lookup_uid(void *, const char *uname, uid_t); 63162852Sdesstatic void cleanup(void *); 64162852Sdes 65162852Sdes/* 66162852Sdes * Installs functions that use getpwnam()/getgrnam()---along with 67162852Sdes * a simple cache to accelerate such lookups---into the archive_write_disk 68162852Sdes * object. This is in a separate file because getpwnam()/getgrnam() 69162852Sdes * can pull in a LOT of library code (including NIS/LDAP functions, which 70162852Sdes * pull in DNS resolveers, etc). This can easily top 500kB, which makes 71162852Sdes * it inappropriate for some space-constrained applications. 72162852Sdes * 73162852Sdes * Applications that are size-sensitive may want to just use the 74162852Sdes * real default functions (defined in archive_write_disk.c) that just 75162852Sdes * use the uid/gid without the lookup. Or define your own custom functions 76162852Sdes * if you prefer. 77162852Sdes * 78162852Sdes * TODO: Replace these hash tables with simpler move-to-front LRU 79162852Sdes * lists with a bounded size (128 items?). The hash is a bit faster, 80162852Sdes * but has a bad pathology in which it thrashes a single bucket. Even 81162852Sdes * walking a list of 128 items is a lot faster than calling 82162852Sdes * getpwnam()! 83162852Sdes */ 84162852Sdesint 85162852Sdesarchive_write_disk_set_standard_lookup(struct archive *a) 86162852Sdes{ 87162852Sdes struct bucket *ucache = malloc(cache_size * sizeof(struct bucket)); 88162852Sdes struct bucket *gcache = malloc(cache_size * sizeof(struct bucket)); 89162852Sdes memset(ucache, 0, cache_size * sizeof(struct bucket)); 90162852Sdes memset(gcache, 0, cache_size * sizeof(struct bucket)); 91 archive_write_disk_set_group_lookup(a, gcache, lookup_gid, cleanup); 92 archive_write_disk_set_user_lookup(a, ucache, lookup_uid, cleanup); 93 return (ARCHIVE_OK); 94} 95 96static gid_t 97lookup_gid(void *private_data, const char *gname, gid_t gid) 98{ 99 int h; 100 struct bucket *b; 101 struct bucket *gcache = (struct bucket *)private_data; 102 103 /* If no gname, just use the gid provided. */ 104 if (gname == NULL || *gname == '\0') 105 return (gid); 106 107 /* Try to find gname in the cache. */ 108 h = hash(gname); 109 b = &gcache[h % cache_size ]; 110 if (b->name != NULL && b->hash == h && strcmp(gname, b->name) == 0) 111 return ((gid_t)b->id); 112 113 /* Free the cache slot for a new entry. */ 114 if (b->name != NULL) 115 free(b->name); 116 b->name = strdup(gname); 117 /* Note: If strdup fails, that's okay; we just won't cache. */ 118 b->hash = h; 119#if HAVE_GRP_H 120# if HAVE_GETGRNAM_R 121 { 122 char _buffer[128]; 123 size_t bufsize = 128; 124 char *buffer = _buffer; 125 struct group grent, *result; 126 int r; 127 128 for (;;) { 129 result = &grent; /* Old getgrnam_r ignores last arg. */ 130 r = getgrnam_r(gname, &grent, buffer, bufsize, &result); 131 if (r == 0) 132 break; 133 if (r != ERANGE) 134 break; 135 bufsize *= 2; 136 if (buffer != _buffer) 137 free(buffer); 138 buffer = malloc(bufsize); 139 if (buffer == NULL) 140 break; 141 } 142 if (result != NULL) 143 gid = result->gr_gid; 144 if (buffer != _buffer) 145 free(buffer); 146 } 147# else /* HAVE_GETGRNAM_R */ 148 { 149 struct group *result; 150 151 result = getgrnam(gname); 152 if (result != NULL) 153 gid = result->gr_gid; 154 } 155# endif /* HAVE_GETGRNAM_R */ 156#elif defined(_WIN32) && !defined(__CYGWIN__) 157 /* TODO: do a gname->gid lookup for Windows. */ 158#else 159 #error No way to perform gid lookups on this platform 160#endif 161 b->id = gid; 162 163 return (gid); 164} 165 166static uid_t 167lookup_uid(void *private_data, const char *uname, uid_t uid) 168{ 169 int h; 170 struct bucket *b; 171 struct bucket *ucache = (struct bucket *)private_data; 172 173 /* If no uname, just use the uid provided. */ 174 if (uname == NULL || *uname == '\0') 175 return (uid); 176 177 /* Try to find uname in the cache. */ 178 h = hash(uname); 179 b = &ucache[h % cache_size ]; 180 if (b->name != NULL && b->hash == h && strcmp(uname, b->name) == 0) 181 return ((uid_t)b->id); 182 183 /* Free the cache slot for a new entry. */ 184 if (b->name != NULL) 185 free(b->name); 186 b->name = strdup(uname); 187 /* Note: If strdup fails, that's okay; we just won't cache. */ 188 b->hash = h; 189#if HAVE_PWD_H 190# if HAVE_GETPWNAM_R 191 { 192 char _buffer[128]; 193 size_t bufsize = 128; 194 char *buffer = _buffer; 195 struct passwd pwent, *result; 196 int r; 197 198 for (;;) { 199 result = &pwent; /* Old getpwnam_r ignores last arg. */ 200 r = getpwnam_r(uname, &pwent, buffer, bufsize, &result); 201 if (r == 0) 202 break; 203 if (r != ERANGE) 204 break; 205 bufsize *= 2; 206 if (buffer != _buffer) 207 free(buffer); 208 buffer = malloc(bufsize); 209 if (buffer == NULL) 210 break; 211 } 212 if (result != NULL) 213 uid = result->pw_uid; 214 if (buffer != _buffer) 215 free(buffer); 216 } 217# else /* HAVE_GETPWNAM_R */ 218 { 219 struct passwd *result; 220 221 result = getpwnam(uname); 222 if (result != NULL) 223 uid = result->pw_uid; 224 } 225#endif /* HAVE_GETPWNAM_R */ 226#elif defined(_WIN32) && !defined(__CYGWIN__) 227 /* TODO: do a uname->uid lookup for Windows. */ 228#else 229 #error No way to look up uids on this platform 230#endif 231 b->id = uid; 232 233 return (uid); 234} 235 236static void 237cleanup(void *private) 238{ 239 size_t i; 240 struct bucket *cache = (struct bucket *)private; 241 242 for (i = 0; i < cache_size; i++) 243 free(cache[i].name); 244 free(cache); 245} 246 247 248static unsigned int 249hash(const char *p) 250{ 251 /* A 32-bit version of Peter Weinberger's (PJW) hash algorithm, 252 as used by ELF for hashing function names. */ 253 unsigned g, h = 0; 254 while (*p != '\0') { 255 h = (h << 4) + *p++; 256 if ((g = h & 0xF0000000) != 0) { 257 h ^= g >> 24; 258 h &= 0x0FFFFFFF; 259 } 260 } 261 return h; 262} 263