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("$FreeBSD$");
29 #ifdef HAVE_SYS_STAT_H
44 #include "archive_entry.h"
47 * This is mostly a pretty straightforward hash table implementation.
48 * The only interesting bit is the different strategies used to
49 * match up links. These strategies match those used by various
51 * tar - content stored with first link, remainder refer back to it.
52 * This requires us to match each subsequent link up with the
54 * cpio - Old cpio just stored body with each link, match-ups were
55 * implicit. This is trivial.
56 * new cpio - New cpio only stores body with last link, match-ups
57 * are implicit. This is actually quite tricky; see the notes
61 /* Users pass us a format code, we translate that into a strategy here. */
62 #define ARCHIVE_ENTRY_LINKIFY_LIKE_TAR 0
63 #define ARCHIVE_ENTRY_LINKIFY_LIKE_MTREE 1
64 #define ARCHIVE_ENTRY_LINKIFY_LIKE_OLD_CPIO 2
65 #define ARCHIVE_ENTRY_LINKIFY_LIKE_NEW_CPIO 3
67 /* Initial size of link cache. */
68 #define links_cache_initial_size 1024
71 struct links_entry *next;
72 struct links_entry *previous;
73 int links; /* # links not yet seen */
75 struct archive_entry *canonical;
76 struct archive_entry *entry;
79 struct archive_entry_linkresolver {
80 struct links_entry **buckets;
81 struct links_entry *spare;
82 unsigned long number_entries;
83 size_t number_buckets;
87 static struct links_entry *find_entry(struct archive_entry_linkresolver *,
88 struct archive_entry *);
89 static void grow_hash(struct archive_entry_linkresolver *);
90 static struct links_entry *insert_entry(struct archive_entry_linkresolver *,
91 struct archive_entry *);
92 static struct links_entry *next_entry(struct archive_entry_linkresolver *);
94 struct archive_entry_linkresolver *
95 archive_entry_linkresolver_new(void)
97 struct archive_entry_linkresolver *res;
100 res = malloc(sizeof(struct archive_entry_linkresolver));
103 memset(res, 0, sizeof(struct archive_entry_linkresolver));
104 res->number_buckets = links_cache_initial_size;
105 res->buckets = malloc(res->number_buckets *
106 sizeof(res->buckets[0]));
107 if (res->buckets == NULL) {
111 for (i = 0; i < res->number_buckets; i++)
112 res->buckets[i] = NULL;
117 archive_entry_linkresolver_set_strategy(struct archive_entry_linkresolver *res,
120 int fmtbase = fmt & ARCHIVE_FORMAT_BASE_MASK;
123 case ARCHIVE_FORMAT_CPIO:
125 case ARCHIVE_FORMAT_CPIO_SVR4_NOCRC:
126 case ARCHIVE_FORMAT_CPIO_SVR4_CRC:
127 res->strategy = ARCHIVE_ENTRY_LINKIFY_LIKE_NEW_CPIO;
130 res->strategy = ARCHIVE_ENTRY_LINKIFY_LIKE_OLD_CPIO;
134 case ARCHIVE_FORMAT_MTREE:
135 res->strategy = ARCHIVE_ENTRY_LINKIFY_LIKE_MTREE;
137 case ARCHIVE_FORMAT_TAR:
138 res->strategy = ARCHIVE_ENTRY_LINKIFY_LIKE_TAR;
141 res->strategy = ARCHIVE_ENTRY_LINKIFY_LIKE_TAR;
147 archive_entry_linkresolver_free(struct archive_entry_linkresolver *res)
149 struct links_entry *le;
154 if (res->buckets != NULL) {
155 while ((le = next_entry(res)) != NULL)
156 archive_entry_free(le->entry);
164 archive_entry_linkify(struct archive_entry_linkresolver *res,
165 struct archive_entry **e, struct archive_entry **f)
167 struct links_entry *le;
168 struct archive_entry *t;
170 *f = NULL; /* Default: Don't return a second entry. */
173 le = next_entry(res);
181 /* If it has only one link, then we're done. */
182 if (archive_entry_nlink(*e) == 1)
184 /* Directories, devices never have hardlinks. */
185 if (archive_entry_filetype(*e) == AE_IFDIR
186 || archive_entry_filetype(*e) == AE_IFBLK
187 || archive_entry_filetype(*e) == AE_IFCHR)
190 switch (res->strategy) {
191 case ARCHIVE_ENTRY_LINKIFY_LIKE_TAR:
192 le = find_entry(res, *e);
194 archive_entry_unset_size(*e);
195 archive_entry_copy_hardlink(*e,
196 archive_entry_pathname(le->canonical));
198 insert_entry(res, *e);
200 case ARCHIVE_ENTRY_LINKIFY_LIKE_MTREE:
201 le = find_entry(res, *e);
203 archive_entry_copy_hardlink(*e,
204 archive_entry_pathname(le->canonical));
206 insert_entry(res, *e);
208 case ARCHIVE_ENTRY_LINKIFY_LIKE_OLD_CPIO:
209 /* This one is trivial. */
211 case ARCHIVE_ENTRY_LINKIFY_LIKE_NEW_CPIO:
212 le = find_entry(res, *e);
215 * Put the new entry in le, return the
221 /* Make the old entry into a hardlink. */
222 archive_entry_unset_size(*e);
223 archive_entry_copy_hardlink(*e,
224 archive_entry_pathname(le->canonical));
225 /* If we ran out of links, return the
226 * final entry as well. */
227 if (le->links == 0) {
233 * If we haven't seen it, tuck it away
236 le = insert_entry(res, *e);
247 static struct links_entry *
248 find_entry(struct archive_entry_linkresolver *res,
249 struct archive_entry *entry)
251 struct links_entry *le;
256 /* Free a held entry. */
257 if (res->spare != NULL) {
258 archive_entry_free(res->spare->canonical);
259 archive_entry_free(res->spare->entry);
264 /* If the links cache overflowed and got flushed, don't bother. */
265 if (res->buckets == NULL)
268 dev = archive_entry_dev(entry);
269 ino = archive_entry_ino64(entry);
270 hash = (int)(dev ^ ino);
272 /* Try to locate this entry in the links cache. */
273 bucket = hash % res->number_buckets;
274 for (le = res->buckets[bucket]; le != NULL; le = le->next) {
276 && dev == archive_entry_dev(le->canonical)
277 && ino == archive_entry_ino64(le->canonical)) {
279 * Decrement link count each time and release
280 * the entry if it hits zero. This saves
281 * memory and is necessary for detecting
287 /* Remove it from this hash bucket. */
288 if (le->previous != NULL)
289 le->previous->next = le->next;
290 if (le->next != NULL)
291 le->next->previous = le->previous;
292 if (res->buckets[bucket] == le)
293 res->buckets[bucket] = le->next;
294 res->number_entries--;
295 /* Defer freeing this entry. */
303 static struct links_entry *
304 next_entry(struct archive_entry_linkresolver *res)
306 struct links_entry *le;
309 /* Free a held entry. */
310 if (res->spare != NULL) {
311 archive_entry_free(res->spare->canonical);
316 /* If the links cache overflowed and got flushed, don't bother. */
317 if (res->buckets == NULL)
320 /* Look for next non-empty bucket in the links cache. */
321 for (bucket = 0; bucket < res->number_buckets; bucket++) {
322 le = res->buckets[bucket];
324 /* Remove it from this hash bucket. */
325 if (le->next != NULL)
326 le->next->previous = le->previous;
327 res->buckets[bucket] = le->next;
328 res->number_entries--;
329 /* Defer freeing this entry. */
337 static struct links_entry *
338 insert_entry(struct archive_entry_linkresolver *res,
339 struct archive_entry *entry)
341 struct links_entry *le;
344 /* Add this entry to the links cache. */
345 le = malloc(sizeof(struct links_entry));
348 memset(le, 0, sizeof(*le));
349 le->canonical = archive_entry_clone(entry);
351 /* If the links cache is getting too full, enlarge the hash table. */
352 if (res->number_entries > res->number_buckets * 2)
355 hash = archive_entry_dev(entry) ^ archive_entry_ino64(entry);
356 bucket = hash % res->number_buckets;
358 /* If we could allocate the entry, record it. */
359 if (res->buckets[bucket] != NULL)
360 res->buckets[bucket]->previous = le;
361 res->number_entries++;
362 le->next = res->buckets[bucket];
364 res->buckets[bucket] = le;
366 le->links = archive_entry_nlink(entry) - 1;
371 grow_hash(struct archive_entry_linkresolver *res)
373 struct links_entry *le, **new_buckets;
377 /* Try to enlarge the bucket list. */
378 new_size = res->number_buckets * 2;
379 new_buckets = malloc(new_size * sizeof(struct links_entry *));
381 if (new_buckets != NULL) {
382 memset(new_buckets, 0,
383 new_size * sizeof(struct links_entry *));
384 for (i = 0; i < res->number_buckets; i++) {
385 while (res->buckets[i] != NULL) {
386 /* Remove entry from old bucket. */
387 le = res->buckets[i];
388 res->buckets[i] = le->next;
390 /* Add entry to new bucket. */
391 bucket = le->hash % new_size;
393 if (new_buckets[bucket] != NULL)
394 new_buckets[bucket]->previous =
396 le->next = new_buckets[bucket];
398 new_buckets[bucket] = le;
402 res->buckets = new_buckets;
403 res->number_buckets = new_size;