2 * Copyright (c) 2003-2007 Tim Kientzle
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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.
26 #include "archive_platform.h"
27 __FBSDID("$FreeBSD: head/lib/libarchive/archive_write_disk_set_standard_lookup.c 201083 2009-12-28 02:09:57Z kientzle $");
29 #ifdef HAVE_SYS_TYPES_H
30 #include <sys/types.h>
49 #include "archive_private.h"
50 #include "archive_read_private.h"
51 #include "archive_write_disk_private.h"
59 static const size_t cache_size = 127;
60 static unsigned int hash(const char *);
61 static int64_t lookup_gid(void *, const char *uname, int64_t);
62 static int64_t lookup_uid(void *, const char *uname, int64_t);
63 static void cleanup(void *);
66 * Installs functions that use getpwnam()/getgrnam()---along with
67 * a simple cache to accelerate such lookups---into the archive_write_disk
68 * object. This is in a separate file because getpwnam()/getgrnam()
69 * can pull in a LOT of library code (including NIS/LDAP functions, which
70 * pull in DNS resolvers, etc). This can easily top 500kB, which makes
71 * it inappropriate for some space-constrained applications.
73 * Applications that are size-sensitive may want to just use the
74 * real default functions (defined in archive_write_disk.c) that just
75 * use the uid/gid without the lookup. Or define your own custom functions
78 * TODO: Replace these hash tables with simpler move-to-front LRU
79 * lists with a bounded size (128 items?). The hash is a bit faster,
80 * but has a bad pathology in which it thrashes a single bucket. Even
81 * walking a list of 128 items is a lot faster than calling
85 archive_write_disk_set_standard_lookup(struct archive *a)
87 struct bucket *ucache = calloc(cache_size, sizeof(struct bucket));
88 struct bucket *gcache = calloc(cache_size, sizeof(struct bucket));
89 if (ucache == NULL || gcache == NULL) {
92 return (ARCHIVE_FATAL);
94 archive_write_disk_set_group_lookup(a, gcache, lookup_gid, cleanup);
95 archive_write_disk_set_user_lookup(a, ucache, lookup_uid, cleanup);
100 lookup_gid(void *private_data, const char *gname, int64_t gid)
104 struct bucket *gcache = (struct bucket *)private_data;
106 /* If no gname, just use the gid provided. */
107 if (gname == NULL || *gname == '\0')
110 /* Try to find gname in the cache. */
112 b = &gcache[h % cache_size ];
113 if (b->name != NULL && b->hash == h && strcmp(gname, b->name) == 0)
114 return ((gid_t)b->id);
116 /* Free the cache slot for a new entry. */
119 b->name = strdup(gname);
120 /* Note: If strdup fails, that's okay; we just won't cache. */
126 size_t bufsize = 128;
127 char *buffer = _buffer;
128 char *allocated = NULL;
129 struct group grent, *result;
133 result = &grent; /* Old getgrnam_r ignores last arg. */
134 r = getgrnam_r(gname, &grent, buffer, bufsize, &result);
141 allocated = malloc(bufsize);
142 if (allocated == NULL)
147 gid = result->gr_gid;
150 # else /* HAVE_GETGRNAM_R */
152 struct group *result;
154 result = getgrnam(gname);
156 gid = result->gr_gid;
158 # endif /* HAVE_GETGRNAM_R */
159 #elif defined(_WIN32) && !defined(__CYGWIN__)
160 /* TODO: do a gname->gid lookup for Windows. */
162 #error No way to perform gid lookups on this platform
170 lookup_uid(void *private_data, const char *uname, int64_t uid)
174 struct bucket *ucache = (struct bucket *)private_data;
176 /* If no uname, just use the uid provided. */
177 if (uname == NULL || *uname == '\0')
180 /* Try to find uname in the cache. */
182 b = &ucache[h % cache_size ];
183 if (b->name != NULL && b->hash == h && strcmp(uname, b->name) == 0)
184 return ((uid_t)b->id);
186 /* Free the cache slot for a new entry. */
189 b->name = strdup(uname);
190 /* Note: If strdup fails, that's okay; we just won't cache. */
196 size_t bufsize = 128;
197 char *buffer = _buffer;
198 char *allocated = NULL;
199 struct passwd pwent, *result;
203 result = &pwent; /* Old getpwnam_r ignores last arg. */
204 r = getpwnam_r(uname, &pwent, buffer, bufsize, &result);
211 allocated = malloc(bufsize);
212 if (allocated == NULL)
217 uid = result->pw_uid;
220 # else /* HAVE_GETPWNAM_R */
222 struct passwd *result;
224 result = getpwnam(uname);
226 uid = result->pw_uid;
228 #endif /* HAVE_GETPWNAM_R */
229 #elif defined(_WIN32) && !defined(__CYGWIN__)
230 /* TODO: do a uname->uid lookup for Windows. */
232 #error No way to look up uids on this platform
240 cleanup(void *private)
243 struct bucket *cache = (struct bucket *)private;
245 for (i = 0; i < cache_size; i++)
254 /* A 32-bit version of Peter Weinberger's (PJW) hash algorithm,
255 as used by ELF for hashing function names. */
259 if ((g = h & 0xF0000000) != 0) {