568 lines
14 KiB
C
Executable File
568 lines
14 KiB
C
Executable File
/*
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zip_open.c -- open zip archive
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Copyright (C) 1999-2008 Dieter Baron and Thomas Klausner
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This file is part of libzip, a library to manipulate ZIP archives.
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The authors can be contacted at <libzip@nih.at>
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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1. Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the
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distribution.
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3. The names of the authors may not be used to endorse or promote
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products derived from this software without specific prior
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written permission.
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THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS
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OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
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DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
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IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
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IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/stat.h>
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#include <errno.h>
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#include <limits.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "zipint.h"
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static void set_error(int *, struct zip_error *, int);
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static struct zip *_zip_allocate_new(const char *, int *);
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static int _zip_checkcons(FILE *, struct zip_cdir *, struct zip_error *);
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static void _zip_check_torrentzip(struct zip *);
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static struct zip_cdir *_zip_find_central_dir(FILE *, int, int *, off_t);
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static int _zip_file_exists(const char *, int, int *);
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static int _zip_headercomp(struct zip_dirent *, int,
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struct zip_dirent *, int);
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static unsigned char *_zip_memmem(const unsigned char *, int,
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const unsigned char *, int);
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static struct zip_cdir *_zip_readcdir(FILE *, unsigned char *, unsigned char *,
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int, int, struct zip_error *);
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ZIP_EXTERN struct zip *
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zip_open(const char *fn, int flags, int *zep)
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{
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FILE *fp;
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struct zip *za;
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struct zip_cdir *cdir;
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int i;
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off_t len;
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switch (_zip_file_exists(fn, flags, zep)) {
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case -1:
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return NULL;
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case 0:
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return _zip_allocate_new(fn, zep);
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default:
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break;
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}
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if ((fp=fopen(fn, "rb")) == NULL) {
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set_error(zep, NULL, ZIP_ER_OPEN);
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return NULL;
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}
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fseeko(fp, 0, SEEK_END);
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len = ftello(fp);
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/* treat empty files as empty archives */
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if (len == 0) {
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if ((za=_zip_allocate_new(fn, zep)) == NULL)
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fclose(fp);
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else
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za->zp = fp;
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return za;
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}
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cdir = _zip_find_central_dir(fp, flags, zep, len);
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if (cdir == NULL) {
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fclose(fp);
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return NULL;
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}
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if ((za=_zip_allocate_new(fn, zep)) == NULL) {
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_zip_cdir_free(cdir);
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fclose(fp);
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return NULL;
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}
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za->cdir = cdir;
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za->zp = fp;
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if ((za->entry=(struct zip_entry *)malloc(sizeof(*(za->entry))
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* cdir->nentry)) == NULL) {
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set_error(zep, NULL, ZIP_ER_MEMORY);
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_zip_free(za);
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return NULL;
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}
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for (i=0; i<cdir->nentry; i++)
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_zip_entry_new(za);
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_zip_check_torrentzip(za);
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za->ch_flags = za->flags;
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return za;
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}
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static void
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set_error(int *zep, struct zip_error *err, int ze)
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{
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int se;
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if (err) {
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_zip_error_get(err, &ze, &se);
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if (zip_error_get_sys_type(ze) == ZIP_ET_SYS)
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errno = se;
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}
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if (zep)
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*zep = ze;
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}
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/* _zip_readcdir:
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tries to find a valid end-of-central-directory at the beginning of
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buf, and then the corresponding central directory entries.
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Returns a struct zip_cdir which contains the central directory
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entries, or NULL if unsuccessful. */
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static struct zip_cdir *
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_zip_readcdir(FILE *fp, unsigned char *buf, unsigned char *eocd, int buflen,
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int flags, struct zip_error *error)
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{
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struct zip_cdir *cd;
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unsigned char *cdp, **bufp;
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int i, comlen, nentry;
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unsigned int left;
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comlen = buf + buflen - eocd - EOCDLEN;
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if (comlen < 0) {
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/* not enough bytes left for comment */
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_zip_error_set(error, ZIP_ER_NOZIP, 0);
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return NULL;
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}
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/* check for end-of-central-dir magic */
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if (memcmp(eocd, EOCD_MAGIC, 4) != 0) {
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_zip_error_set(error, ZIP_ER_NOZIP, 0);
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return NULL;
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}
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if (memcmp(eocd+4, "\0\0\0\0", 4) != 0) {
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_zip_error_set(error, ZIP_ER_MULTIDISK, 0);
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return NULL;
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}
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cdp = eocd + 8;
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/* number of cdir-entries on this disk */
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i = _zip_read2(&cdp);
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/* number of cdir-entries */
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nentry = _zip_read2(&cdp);
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if ((cd=_zip_cdir_new(nentry, error)) == NULL)
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return NULL;
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cd->size = _zip_read4(&cdp);
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cd->offset = _zip_read4(&cdp);
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cd->comment = NULL;
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cd->comment_len = _zip_read2(&cdp);
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if ((comlen < cd->comment_len) || (cd->nentry != i)) {
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_zip_error_set(error, ZIP_ER_NOZIP, 0);
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free(cd);
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return NULL;
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}
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if ((flags & ZIP_CHECKCONS) && comlen != cd->comment_len) {
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_zip_error_set(error, ZIP_ER_INCONS, 0);
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free(cd);
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return NULL;
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}
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if (cd->comment_len) {
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if ((cd->comment=(char *)_zip_memdup(eocd+EOCDLEN,
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cd->comment_len, error))
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== NULL) {
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free(cd);
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return NULL;
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}
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}
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if (cd->size < (unsigned int)(eocd-buf)) {
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/* if buffer already read in, use it */
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cdp = eocd - cd->size;
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bufp = &cdp;
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}
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else {
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/* go to start of cdir and read it entry by entry */
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bufp = NULL;
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clearerr(fp);
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fseeko(fp, cd->offset, SEEK_SET);
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/* possible consistency check: cd->offset =
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len-(cd->size+cd->comment_len+EOCDLEN) ? */
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if (ferror(fp) || ((unsigned long)ftello(fp) != cd->offset)) {
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/* seek error or offset of cdir wrong */
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if (ferror(fp))
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_zip_error_set(error, ZIP_ER_SEEK, errno);
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else
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_zip_error_set(error, ZIP_ER_NOZIP, 0);
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free(cd);
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return NULL;
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}
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}
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left = cd->size;
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i=0;
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do {
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if (i == cd->nentry && left > 0) {
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/* Infozip extension for more than 64k entries:
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nentries wraps around, size indicates correct EOCD */
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_zip_cdir_grow(cd, cd->nentry+0x10000, error);
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}
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if ((_zip_dirent_read(cd->entry+i, fp, bufp, &left, 0, error)) < 0) {
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cd->nentry = i;
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_zip_cdir_free(cd);
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return NULL;
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}
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i++;
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} while (i<cd->nentry);
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return cd;
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}
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/* _zip_checkcons:
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Checks the consistency of the central directory by comparing central
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directory entries with local headers and checking for plausible
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file and header offsets. Returns -1 if not plausible, else the
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difference between the lowest and the highest fileposition reached */
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static int
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_zip_checkcons(FILE *fp, struct zip_cdir *cd, struct zip_error *error)
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{
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int i;
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unsigned int min, max, j;
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struct zip_dirent temp;
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if (cd->nentry) {
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max = cd->entry[0].offset;
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min = cd->entry[0].offset;
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}
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else
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min = max = 0;
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for (i=0; i<cd->nentry; i++) {
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if (cd->entry[i].offset < min)
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min = cd->entry[i].offset;
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if (min > cd->offset) {
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_zip_error_set(error, ZIP_ER_NOZIP, 0);
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return -1;
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}
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j = cd->entry[i].offset + cd->entry[i].comp_size
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+ cd->entry[i].filename_len + LENTRYSIZE;
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if (j > max)
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max = j;
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if (max > cd->offset) {
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_zip_error_set(error, ZIP_ER_NOZIP, 0);
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return -1;
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}
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if (fseeko(fp, cd->entry[i].offset, SEEK_SET) != 0) {
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_zip_error_set(error, ZIP_ER_SEEK, 0);
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return -1;
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}
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if (_zip_dirent_read(&temp, fp, NULL, NULL, 1, error) == -1)
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return -1;
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if (_zip_headercomp(cd->entry+i, 0, &temp, 1) != 0) {
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_zip_error_set(error, ZIP_ER_INCONS, 0);
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_zip_dirent_finalize(&temp);
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return -1;
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}
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_zip_dirent_finalize(&temp);
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}
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return max - min;
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}
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/* _zip_check_torrentzip:
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check wether ZA has a valid TORRENTZIP comment, i.e. is torrentzipped */
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static void
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_zip_check_torrentzip(struct zip *za)
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{
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uLong crc_got, crc_should;
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char buf[8+1];
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char *end;
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if (za->zp == NULL || za->cdir == NULL)
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return;
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if (za->cdir->comment_len != TORRENT_SIG_LEN+8
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|| strncmp(za->cdir->comment, TORRENT_SIG, TORRENT_SIG_LEN) != 0)
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return;
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memcpy(buf, za->cdir->comment+TORRENT_SIG_LEN, 8);
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buf[8] = '\0';
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errno = 0;
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crc_should = strtoul(buf, &end, 16);
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if ((crc_should == UINT_MAX && errno != 0) || (end && *end))
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return;
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if (_zip_filerange_crc(za->zp, za->cdir->offset, za->cdir->size,
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&crc_got, NULL) < 0)
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return;
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if (crc_got == crc_should)
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za->flags |= ZIP_AFL_TORRENT;
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}
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/* _zip_headercomp:
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compares two headers h1 and h2; if they are local headers, set
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local1p or local2p respectively to 1, else 0. Return 0 if they
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are identical, -1 if not. */
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static int
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_zip_headercomp(struct zip_dirent *h1, int local1p, struct zip_dirent *h2,
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int local2p)
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{
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if ((h1->version_needed != h2->version_needed)
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#if 0
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/* some zip-files have different values in local
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and global headers for the bitflags */
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|| (h1->bitflags != h2->bitflags)
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#endif
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|| (h1->comp_method != h2->comp_method)
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|| (h1->last_mod != h2->last_mod)
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|| (h1->filename_len != h2->filename_len)
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|| !h1->filename || !h2->filename
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|| strcmp(h1->filename, h2->filename))
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return -1;
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/* check that CRC and sizes are zero if data descriptor is used */
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if ((h1->bitflags & ZIP_GPBF_DATA_DESCRIPTOR) && local1p
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&& (h1->crc != 0
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|| h1->comp_size != 0
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|| h1->uncomp_size != 0))
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return -1;
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if ((h2->bitflags & ZIP_GPBF_DATA_DESCRIPTOR) && local2p
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&& (h2->crc != 0
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|| h2->comp_size != 0
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|| h2->uncomp_size != 0))
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return -1;
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/* check that CRC and sizes are equal if no data descriptor is used */
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if (((h1->bitflags & ZIP_GPBF_DATA_DESCRIPTOR) == 0 || local1p == 0)
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&& ((h2->bitflags & ZIP_GPBF_DATA_DESCRIPTOR) == 0 || local2p == 0)) {
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if ((h1->crc != h2->crc)
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|| (h1->comp_size != h2->comp_size)
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|| (h1->uncomp_size != h2->uncomp_size))
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return -1;
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}
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if ((local1p == local2p)
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&& ((h1->extrafield_len != h2->extrafield_len)
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|| (h1->extrafield_len && h2->extrafield
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&& memcmp(h1->extrafield, h2->extrafield,
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h1->extrafield_len))))
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return -1;
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/* if either is local, nothing more to check */
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if (local1p || local2p)
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return 0;
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if ((h1->version_madeby != h2->version_madeby)
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|| (h1->disk_number != h2->disk_number)
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|| (h1->int_attrib != h2->int_attrib)
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|| (h1->ext_attrib != h2->ext_attrib)
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|| (h1->offset != h2->offset)
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|| (h1->comment_len != h2->comment_len)
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|| (h1->comment_len && h2->comment
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&& memcmp(h1->comment, h2->comment, h1->comment_len)))
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return -1;
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return 0;
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}
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static struct zip *
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_zip_allocate_new(const char *fn, int *zep)
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{
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struct zip *za;
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struct zip_error error;
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if ((za=_zip_new(&error)) == NULL) {
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set_error(zep, &error, 0);
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return NULL;
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}
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za->zn = strdup(fn);
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if (!za->zn) {
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_zip_free(za);
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set_error(zep, NULL, ZIP_ER_MEMORY);
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return NULL;
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}
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return za;
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}
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static int
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_zip_file_exists(const char *fn, int flags, int *zep)
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{
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struct stat st;
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if (fn == NULL) {
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set_error(zep, NULL, ZIP_ER_INVAL);
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return -1;
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}
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if (stat(fn, &st) != 0) {
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if (flags & ZIP_CREATE)
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return 0;
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else {
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set_error(zep, NULL, ZIP_ER_OPEN);
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return -1;
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}
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}
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else if ((flags & ZIP_EXCL)) {
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set_error(zep, NULL, ZIP_ER_EXISTS);
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return -1;
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}
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/* ZIP_CREATE gets ignored if file exists and not ZIP_EXCL,
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just like open() */
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return 1;
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}
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static struct zip_cdir *
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_zip_find_central_dir(FILE *fp, int flags, int *zep, off_t len)
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{
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struct zip_cdir *cdir, *cdirnew;
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unsigned char *buf, *match;
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int a, best, buflen, i;
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struct zip_error zerr;
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i = fseeko(fp, -(len < CDBUFSIZE ? len : CDBUFSIZE), SEEK_END);
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if (i == -1 && errno != EFBIG) {
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/* seek before start of file on my machine */
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set_error(zep, NULL, ZIP_ER_SEEK);
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return NULL;
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}
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/* 64k is too much for stack */
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if ((buf=(unsigned char *)malloc(CDBUFSIZE)) == NULL) {
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set_error(zep, NULL, ZIP_ER_MEMORY);
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return NULL;
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}
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clearerr(fp);
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buflen = fread(buf, 1, CDBUFSIZE, fp);
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if (ferror(fp)) {
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set_error(zep, NULL, ZIP_ER_READ);
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free(buf);
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return NULL;
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}
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best = -1;
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cdir = NULL;
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match = buf;
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_zip_error_set(&zerr, ZIP_ER_NOZIP, 0);
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while ((match=_zip_memmem(match, buflen-(match-buf)-18,
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(const unsigned char *)EOCD_MAGIC, 4))!=NULL) {
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/* found match -- check, if good */
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/* to avoid finding the same match all over again */
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match++;
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if ((cdirnew=_zip_readcdir(fp, buf, match-1, buflen, flags,
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&zerr)) == NULL)
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continue;
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if (cdir) {
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if (best <= 0)
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best = _zip_checkcons(fp, cdir, &zerr);
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a = _zip_checkcons(fp, cdirnew, &zerr);
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if (best < a) {
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_zip_cdir_free(cdir);
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cdir = cdirnew;
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best = a;
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}
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else
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_zip_cdir_free(cdirnew);
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||
}
|
||
else {
|
||
cdir = cdirnew;
|
||
if (flags & ZIP_CHECKCONS)
|
||
best = _zip_checkcons(fp, cdir, &zerr);
|
||
else
|
||
best = 0;
|
||
}
|
||
cdirnew = NULL;
|
||
}
|
||
|
||
free(buf);
|
||
|
||
if (best < 0) {
|
||
set_error(zep, &zerr, 0);
|
||
_zip_cdir_free(cdir);
|
||
return NULL;
|
||
}
|
||
|
||
return cdir;
|
||
}
|
||
|
||
|
||
|
||
static unsigned char *
|
||
_zip_memmem(const unsigned char *big, int biglen, const unsigned char *little,
|
||
int littlelen)
|
||
{
|
||
const unsigned char *p;
|
||
|
||
if ((biglen < littlelen) || (littlelen == 0))
|
||
return NULL;
|
||
p = big-1;
|
||
while ((p=(const unsigned char *)
|
||
memchr(p+1, little[0], (size_t)(big-(p+1)+biglen-littlelen+1)))
|
||
!= NULL) {
|
||
if (memcmp(p+1, little+1, littlelen-1)==0)
|
||
return (unsigned char *)p;
|
||
}
|
||
|
||
return NULL;
|
||
}
|