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__)
51int
52archive_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
60static const char * const NO_NAME = "(noname)";
61
62struct 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
75static const char *	lookup_gname(void *, gid_t);
76static const char *	lookup_uname(void *, uid_t);
77static void	cleanup(void *);
78static const char *	lookup_gname_helper(struct name_cache *, id_t gid);
79static 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 resolveers, 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 */
94int
95archive_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
121static void
122cleanup(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 */
141static const char *
142lookup_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
177static const char *
178lookup_uname(void *data, uid_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
185static const char *
186lookup_uname_helper(struct name_cache *cache, id_t id)
187{
188	struct passwd	pwent, *result;
189	int r;
190
191	if (cache->buff_size == 0) {
192		cache->buff_size = 256;
193		cache->buff = malloc(cache->buff_size);
194	}
195	if (cache->buff == NULL)
196		return (NULL);
197	for (;;) {
198		result = &pwent; /* Old getpwuid_r ignores last arg. */
199		r = getpwuid_r((uid_t)id, &pwent,
200			       cache->buff, cache->buff_size, &result);
201		if (r == 0)
202			break;
203		if (r != ERANGE)
204			break;
205		/* ERANGE means our buffer was too small, but POSIX
206		 * doesn't tell us how big the buffer should be, so
207		 * we just double it and try again.  Because the buffer
208		 * is kept around in the cache object, we shouldn't
209		 * have to do this very often. */
210		cache->buff_size *= 2;
211		cache->buff = realloc(cache->buff, cache->buff_size);
212		if (cache->buff == NULL)
213			break;
214	}
215	if (r != 0) {
216		archive_set_error(cache->archive, errno,
217		    "Can't lookup user for id %d", (int)id);
218		return (NULL);
219	}
220	if (result == NULL)
221		return (NULL);
222
223	return strdup(result->pw_name);
224}
225
226static const char *
227lookup_gname(void *data, gid_t gid)
228{
229	struct name_cache *gname_cache = (struct name_cache *)data;
230	return (lookup_name(gname_cache,
231		    &lookup_gname_helper, (id_t)gid));
232}
233
234static const char *
235lookup_gname_helper(struct name_cache *cache, id_t id)
236{
237	struct group	grent, *result;
238	int r;
239
240	if (cache->buff_size == 0) {
241		cache->buff_size = 256;
242		cache->buff = malloc(cache->buff_size);
243	}
244	if (cache->buff == NULL)
245		return (NULL);
246	for (;;) {
247		result = &grent; /* Old getgrgid_r ignores last arg. */
248		r = getgrgid_r((gid_t)id, &grent,
249			       cache->buff, cache->buff_size, &result);
250		if (r == 0)
251			break;
252		if (r != ERANGE)
253			break;
254		/* ERANGE means our buffer was too small, but POSIX
255		 * doesn't tell us how big the buffer should be, so
256		 * we just double it and try again. */
257		cache->buff_size *= 2;
258		cache->buff = realloc(cache->buff, cache->buff_size);
259		if (cache->buff == NULL)
260			break;
261	}
262	if (r != 0) {
263		archive_set_error(cache->archive, errno,
264		    "Can't lookup group for id %d", (int)id);
265		return (NULL);
266	}
267	if (result == NULL)
268		return (NULL);
269
270	return strdup(result->gr_name);
271}
272#endif /* ! (_WIN32 && !__CYGWIN__) */
273