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/*-
* Copyright (c) 2003-2007 Tim Kientzle
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "archive_platform.h"
__FBSDID("$FreeBSD: src/lib/libarchive/archive_entry_link_resolver.c,v 1.1 2007/12/30 04:58:21 kientzle Exp $");
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#include <stdio.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#include "archive_entry.h"
/* Initial size of link cache. */
#define links_cache_initial_size 1024
struct archive_entry_linkresolver {
char *last_name;
unsigned long number_entries;
size_t number_buckets;
struct links_entry **buckets;
};
struct links_entry {
struct links_entry *next;
struct links_entry *previous;
int links;
dev_t dev;
ino_t ino;
char *name;
};
struct archive_entry_linkresolver *
archive_entry_linkresolver_new(void)
{
struct archive_entry_linkresolver *links_cache;
size_t i;
links_cache = malloc(sizeof(struct archive_entry_linkresolver));
if (links_cache == NULL)
return (NULL);
memset(links_cache, 0, sizeof(struct archive_entry_linkresolver));
links_cache->number_buckets = links_cache_initial_size;
links_cache->buckets = malloc(links_cache->number_buckets *
sizeof(links_cache->buckets[0]));
if (links_cache->buckets == NULL) {
free(links_cache);
return (NULL);
}
for (i = 0; i < links_cache->number_buckets; i++)
links_cache->buckets[i] = NULL;
return (links_cache);
}
void
archive_entry_linkresolver_free(struct archive_entry_linkresolver *links_cache)
{
size_t i;
if (links_cache->buckets == NULL)
return;
for (i = 0; i < links_cache->number_buckets; i++) {
while (links_cache->buckets[i] != NULL) {
struct links_entry *lp = links_cache->buckets[i]->next;
if (links_cache->buckets[i]->name != NULL)
free(links_cache->buckets[i]->name);
free(links_cache->buckets[i]);
links_cache->buckets[i] = lp;
}
}
free(links_cache->buckets);
links_cache->buckets = NULL;
}
const char *
archive_entry_linkresolve(struct archive_entry_linkresolver *links_cache,
struct archive_entry *entry)
{
struct links_entry *le, **new_buckets;
int hash;
size_t i, new_size;
dev_t dev;
ino_t ino;
int nlinks;
/* Free a held name. */
free(links_cache->last_name);
links_cache->last_name = NULL;
/* If the links cache overflowed and got flushed, don't bother. */
if (links_cache->buckets == NULL)
return (NULL);
dev = archive_entry_dev(entry);
ino = archive_entry_ino(entry);
nlinks = archive_entry_nlink(entry);
/* An entry with one link can't be a hard link. */
if (nlinks == 1)
return (NULL);
/* If the links cache is getting too full, enlarge the hash table. */
if (links_cache->number_entries > links_cache->number_buckets * 2)
{
/* Try to enlarge the bucket list. */
new_size = links_cache->number_buckets * 2;
new_buckets = malloc(new_size * sizeof(struct links_entry *));
if (new_buckets != NULL) {
memset(new_buckets, 0,
new_size * sizeof(struct links_entry *));
for (i = 0; i < links_cache->number_buckets; i++) {
while (links_cache->buckets[i] != NULL) {
/* Remove entry from old bucket. */
le = links_cache->buckets[i];
links_cache->buckets[i] = le->next;
/* Add entry to new bucket. */
hash = (le->dev ^ le->ino) % new_size;
if (new_buckets[hash] != NULL)
new_buckets[hash]->previous =
le;
le->next = new_buckets[hash];
le->previous = NULL;
new_buckets[hash] = le;
}
}
free(links_cache->buckets);
links_cache->buckets = new_buckets;
links_cache->number_buckets = new_size;
}
}
/* Try to locate this entry in the links cache. */
hash = ( dev ^ ino ) % links_cache->number_buckets;
for (le = links_cache->buckets[hash]; le != NULL; le = le->next) {
if (le->dev == dev && le->ino == ino) {
/*
* Decrement link count each time and release
* the entry if it hits zero. This saves
* memory and is necessary for detecting
* missed links.
*/
--le->links;
if (le->links > 0)
return (le->name);
/*
* When we release the entry, save the name
* until the next call.
*/
links_cache->last_name = le->name;
/*
* Release the entry.
*/
if (le->previous != NULL)
le->previous->next = le->next;
if (le->next != NULL)
le->next->previous = le->previous;
if (links_cache->buckets[hash] == le)
links_cache->buckets[hash] = le->next;
links_cache->number_entries--;
free(le);
return (links_cache->last_name);
}
}
/* Add this entry to the links cache. */
le = malloc(sizeof(struct links_entry));
if (le == NULL)
return (NULL);
le->name = strdup(archive_entry_pathname(entry));
if (le->name == NULL) {
free(le);
return (NULL);
}
/* If we could allocate the entry, record it. */
if (links_cache->buckets[hash] != NULL)
links_cache->buckets[hash]->previous = le;
links_cache->number_entries++;
le->next = links_cache->buckets[hash];
le->previous = NULL;
links_cache->buckets[hash] = le;
le->dev = dev;
le->ino = ino;
le->links = nlinks - 1;
return (NULL);
}
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