1 /*-
2 * Copyright (c) 2003-2007 Tim Kientzle
3 * 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 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26 #include "archive_platform.h"
27 __FBSDID("$FreeBSD: head/lib/libarchive/archive_read_disk_set_standard_lookup.c 201109 2009-12-28 03:30:31Z kientzle $");
28
29 #ifdef HAVE_SYS_TYPES_H
30 #include <sys/types.h>
31 #endif
32 #ifdef HAVE_ERRNO_H
33 #include <errno.h>
34 #endif
35 #ifdef HAVE_GRP_H
36 #include <grp.h>
37 #endif
38 #ifdef HAVE_PWD_H
39 #include <pwd.h>
40 #endif
41 #ifdef HAVE_STDLIB_H
42 #include <stdlib.h>
43 #endif
44 #ifdef HAVE_STRING_H
45 #include <string.h>
46 #endif
47
48 #include "archive.h"
49
50 #if defined(_WIN32) && !defined(__CYGWIN__)
51 int
archive_read_disk_set_standard_lookup(struct archive * a)52 archive_read_disk_set_standard_lookup(struct archive *a)
53 {
54 archive_set_error(a, -1, "Standard lookups not available on Windows");
55 return (ARCHIVE_FATAL);
56 }
57 #else /* ! (_WIN32 && !__CYGWIN__) */
58 #define name_cache_size 127
59
60 static const char * const NO_NAME = "(noname)";
61
62 struct name_cache {
63 struct archive *archive;
64 char *buff;
65 size_t buff_size;
66 int probes;
67 int hits;
68 size_t size;
69 struct {
70 id_t id;
71 const char *name;
72 } cache[name_cache_size];
73 };
74
75 static const char * lookup_gname(void *, int64_t);
76 static const char * lookup_uname(void *, int64_t);
77 static void cleanup(void *);
78 static const char * lookup_gname_helper(struct name_cache *, id_t gid);
79 static const char * lookup_uname_helper(struct name_cache *, id_t uid);
80
81 /*
82 * Installs functions that use getpwuid()/getgrgid()---along with
83 * a simple cache to accelerate such lookups---into the archive_read_disk
84 * object. This is in a separate file because getpwuid()/getgrgid()
85 * can pull in a LOT of library code (including NIS/LDAP functions, which
86 * pull in DNS resolvers, etc). This can easily top 500kB, which makes
87 * it inappropriate for some space-constrained applications.
88 *
89 * Applications that are size-sensitive may want to just use the
90 * real default functions (defined in archive_read_disk.c) that just
91 * use the uid/gid without the lookup. Or define your own custom functions
92 * if you prefer.
93 */
94 int
archive_read_disk_set_standard_lookup(struct archive * a)95 archive_read_disk_set_standard_lookup(struct archive *a)
96 {
97 struct name_cache *ucache = malloc(sizeof(struct name_cache));
98 struct name_cache *gcache = malloc(sizeof(struct name_cache));
99
100 if (ucache == NULL || gcache == NULL) {
101 archive_set_error(a, ENOMEM,
102 "Can't allocate uname/gname lookup cache");
103 free(ucache);
104 free(gcache);
105 return (ARCHIVE_FATAL);
106 }
107
108 memset(ucache, 0, sizeof(*ucache));
109 ucache->archive = a;
110 ucache->size = name_cache_size;
111 memset(gcache, 0, sizeof(*gcache));
112 gcache->archive = a;
113 gcache->size = name_cache_size;
114
115 archive_read_disk_set_gname_lookup(a, gcache, lookup_gname, cleanup);
116 archive_read_disk_set_uname_lookup(a, ucache, lookup_uname, cleanup);
117
118 return (ARCHIVE_OK);
119 }
120
121 static void
cleanup(void * data)122 cleanup(void *data)
123 {
124 struct name_cache *cache = (struct name_cache *)data;
125 size_t i;
126
127 if (cache != NULL) {
128 for (i = 0; i < cache->size; i++) {
129 if (cache->cache[i].name != NULL &&
130 cache->cache[i].name != NO_NAME)
131 free((void *)(uintptr_t)cache->cache[i].name);
132 }
133 free(cache->buff);
134 free(cache);
135 }
136 }
137
138 /*
139 * Lookup uid/gid from uname/gname, return NULL if no match.
140 */
141 static const char *
lookup_name(struct name_cache * cache,const char * (* lookup_fn)(struct name_cache *,id_t),id_t id)142 lookup_name(struct name_cache *cache,
143 const char * (*lookup_fn)(struct name_cache *, id_t), id_t id)
144 {
145 const char *name;
146 int slot;
147
148
149 cache->probes++;
150
151 slot = id % cache->size;
152 if (cache->cache[slot].name != NULL) {
153 if (cache->cache[slot].id == id) {
154 cache->hits++;
155 if (cache->cache[slot].name == NO_NAME)
156 return (NULL);
157 return (cache->cache[slot].name);
158 }
159 if (cache->cache[slot].name != NO_NAME)
160 free((void *)(uintptr_t)cache->cache[slot].name);
161 cache->cache[slot].name = NULL;
162 }
163
164 name = (lookup_fn)(cache, id);
165 if (name == NULL) {
166 /* Cache and return the negative response. */
167 cache->cache[slot].name = NO_NAME;
168 cache->cache[slot].id = id;
169 return (NULL);
170 }
171
172 cache->cache[slot].name = name;
173 cache->cache[slot].id = id;
174 return (cache->cache[slot].name);
175 }
176
177 static const char *
lookup_uname(void * data,int64_t uid)178 lookup_uname(void *data, int64_t uid)
179 {
180 struct name_cache *uname_cache = (struct name_cache *)data;
181 return (lookup_name(uname_cache,
182 &lookup_uname_helper, (id_t)uid));
183 }
184
185 #if HAVE_GETPWUID_R
186 static const char *
lookup_uname_helper(struct name_cache * cache,id_t id)187 lookup_uname_helper(struct name_cache *cache, id_t id)
188 {
189 struct passwd pwent, *result;
190 char * nbuff;
191 size_t nbuff_size;
192 int r;
193
194 if (cache->buff_size == 0) {
195 cache->buff_size = 256;
196 cache->buff = malloc(cache->buff_size);
197 }
198 if (cache->buff == NULL)
199 return (NULL);
200 for (;;) {
201 result = &pwent; /* Old getpwuid_r ignores last arg. */
202 r = getpwuid_r((uid_t)id, &pwent,
203 cache->buff, cache->buff_size, &result);
204 if (r == 0)
205 break;
206 if (r != ERANGE)
207 break;
208 /* ERANGE means our buffer was too small, but POSIX
209 * doesn't tell us how big the buffer should be, so
210 * we just double it and try again. Because the buffer
211 * is kept around in the cache object, we shouldn't
212 * have to do this very often. */
213 nbuff_size = cache->buff_size * 2;
214 nbuff = realloc(cache->buff, nbuff_size);
215 if (nbuff == NULL)
216 break;
217 cache->buff = nbuff;
218 cache->buff_size = nbuff_size;
219 }
220 if (r != 0) {
221 archive_set_error(cache->archive, errno,
222 "Can't lookup user for id %d", (int)id);
223 return (NULL);
224 }
225 if (result == NULL)
226 return (NULL);
227
228 return strdup(result->pw_name);
229 }
230 #else
231 static const char *
lookup_uname_helper(struct name_cache * cache,id_t id)232 lookup_uname_helper(struct name_cache *cache, id_t id)
233 {
234 struct passwd *result;
235 (void)cache; /* UNUSED */
236
237 result = getpwuid((uid_t)id);
238
239 if (result == NULL)
240 return (NULL);
241
242 return strdup(result->pw_name);
243 }
244 #endif
245
246 static const char *
lookup_gname(void * data,int64_t gid)247 lookup_gname(void *data, int64_t gid)
248 {
249 struct name_cache *gname_cache = (struct name_cache *)data;
250 return (lookup_name(gname_cache,
251 &lookup_gname_helper, (id_t)gid));
252 }
253
254 #if HAVE_GETGRGID_R
255 static const char *
lookup_gname_helper(struct name_cache * cache,id_t id)256 lookup_gname_helper(struct name_cache *cache, id_t id)
257 {
258 struct group grent, *result;
259 char * nbuff;
260 size_t nbuff_size;
261 int r;
262
263 if (cache->buff_size == 0) {
264 cache->buff_size = 256;
265 cache->buff = malloc(cache->buff_size);
266 }
267 if (cache->buff == NULL)
268 return (NULL);
269 for (;;) {
270 result = &grent; /* Old getgrgid_r ignores last arg. */
271 r = getgrgid_r((gid_t)id, &grent,
272 cache->buff, cache->buff_size, &result);
273 if (r == 0)
274 break;
275 if (r != ERANGE)
276 break;
277 /* ERANGE means our buffer was too small, but POSIX
278 * doesn't tell us how big the buffer should be, so
279 * we just double it and try again. */
280 nbuff_size = cache->buff_size * 2;
281 nbuff = realloc(cache->buff, nbuff_size);
282 if (nbuff == NULL)
283 break;
284 cache->buff = nbuff;
285 cache->buff_size = nbuff_size;
286 }
287 if (r != 0) {
288 archive_set_error(cache->archive, errno,
289 "Can't lookup group for id %d", (int)id);
290 return (NULL);
291 }
292 if (result == NULL)
293 return (NULL);
294
295 return strdup(result->gr_name);
296 }
297 #else
298 static const char *
lookup_gname_helper(struct name_cache * cache,id_t id)299 lookup_gname_helper(struct name_cache *cache, id_t id)
300 {
301 struct group *result;
302 (void)cache; /* UNUSED */
303
304 result = getgrgid((gid_t)id);
305
306 if (result == NULL)
307 return (NULL);
308
309 return strdup(result->gr_name);
310 }
311 #endif
312
313 #endif /* ! (_WIN32 && !__CYGWIN__) */
314