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: src/lib/libarchive/archive_write_disk_set_standard_lookup.c,v 1.2 2007/04/20 15:32:13 kientzle Exp $");
46 #include "archive_private.h"
47 #include "archive_read_private.h"
48 #include "archive_write_disk_private.h"
56 static const size_t cache_size = 127;
57 static unsigned int hash(const char *);
58 static gid_t lookup_gid(void *, const char *uname, gid_t);
59 static uid_t lookup_uid(void *, const char *uname, uid_t);
60 static void cleanup(void *);
63 * Installs functions that use getpwnam()/getgrnam()---along with
64 * a simple cache to accelerate such lookups---into the archive_write_disk
65 * object. This is in a separate file because getpwnam()/getgrnam()
66 * can pull in a LOT of library code (including NIS/LDAP functions, which
67 * pull in DNS resolveers, etc). This can easily top 500kB, which makes
68 * it inappropriate for some space-constrained applications.
70 * Applications that are size-sensitive may want to just use the
71 * real default functions (defined in archive_write_disk.c) that just
72 * use the uid/gid without the lookup. Or define your own custom functions
75 * TODO: Replace these hash tables with simpler move-to-front LRU
76 * lists with a bounded size (128 items?). The hash is a bit faster,
77 * but has a bad pathology in which it thrashes a single bucket. Even
78 * walking a list of 128 items is a lot faster than calling
82 archive_write_disk_set_standard_lookup(struct archive *a)
84 struct bucket *ucache = malloc(sizeof(struct bucket[cache_size]));
85 struct bucket *gcache = malloc(sizeof(struct bucket[cache_size]));
86 memset(ucache, 0, sizeof(struct bucket[cache_size]));
87 memset(gcache, 0, sizeof(struct bucket[cache_size]));
88 archive_write_disk_set_group_lookup(a, gcache, lookup_gid, cleanup);
89 archive_write_disk_set_user_lookup(a, ucache, lookup_uid, cleanup);
94 lookup_gid(void *private_data, const char *gname, gid_t gid)
98 struct bucket *gcache = (struct bucket *)private_data;
100 /* If no gname, just use the gid provided. */
101 if (gname == NULL || *gname == '\0')
104 /* Try to find gname in the cache. */
106 b = &gcache[h % cache_size ];
107 if (b->name != NULL && b->hash == h && strcmp(gname, b->name) == 0)
108 return ((gid_t)b->id);
110 /* Free the cache slot for a new entry. */
113 b->name = strdup(gname);
114 /* Note: If strdup fails, that's okay; we just won't cache. */
118 struct group *grent = getgrnam(gname);
123 /* TODO: do a gname->gid lookup for Windows. */
131 lookup_uid(void *private_data, const char *uname, uid_t uid)
135 struct bucket *ucache = (struct bucket *)private_data;
137 /* If no uname, just use the uid provided. */
138 if (uname == NULL || *uname == '\0')
141 /* Try to find uname in the cache. */
143 b = &ucache[h % cache_size ];
144 if (b->name != NULL && b->hash == h && strcmp(uname, b->name) == 0)
145 return ((uid_t)b->id);
147 /* Free the cache slot for a new entry. */
150 b->name = strdup(uname);
151 /* Note: If strdup fails, that's okay; we just won't cache. */
155 struct passwd *pwent = getpwnam(uname);
160 /* TODO: do a uname->uid lookup for Windows. */
168 cleanup(void *private)
171 struct bucket *cache = (struct bucket *)private;
173 for (i = 0; i < cache_size; i++)
182 /* A 32-bit version of Peter Weinberger's (PJW) hash algorithm,
183 as used by ELF for hashing function names. */
186 h = ( h << 4 ) + *p++;
187 if (( g = h & 0xF0000000 )) {