lib/zip_open.c - third_party/libzip - Git at Google

 /*
   $NiH: zip_open.c,v 1.22 2004/04/19 11:49:13 dillo Exp $

   zip_open.c -- open zip archive
   Copyright (C) 1999, 2003, 2004 Dieter Baron and Thomas Klausner

   This file is part of libzip, a library to manipulate ZIP archives.
   The authors can be contacted at <nih@giga.or.at>

   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.
   3. The names of the authors may not be used to endorse or promote
      products derived from this software without specific prior
      written permission.

   THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``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 AUTHORS 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 <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/stat.h>

 #include "zip.h"
 #include "zipint.h"

 static void set_error(int *, struct zip_error *, int);
 static int _zip_checkcons(FILE *, struct zip_cdir *, struct zip_error *);
 static int _zip_headercomp(struct zip_dirent *, int,
 			   struct zip_dirent *, int);
 static unsigned char *_zip_memmem(const unsigned char *, int,
 				  const unsigned char *, int);
 static struct zip_cdir *_zip_readcdir(FILE *, unsigned char *, unsigned char *,
 				 int, struct zip_error *);


 struct zip *
 zip_open(const char *fn, int flags, int *zep)
 {
     FILE *fp;
     unsigned char *buf, *match;
     int a, i, buflen, best;
     struct zip *za;
     struct zip_cdir *cdir, *cdirnew;
     long len;
     struct stat st;
     struct zip_error error, err2;

     if (fn == NULL) {
 	set_error(zep, NULL, ZIP_ER_INVAL);
 	return NULL;
     }

     if (stat(fn, &st) != 0) {
 	if (flags & ZIP_CREATE) {
 	    if ((za=_zip_new(&error)) == NULL) {
 		set_error(zep, &error, 0);
 		return NULL;
 	    }

 	    za->zn = strdup(fn);
 	    if (!za->zn) {
 		_zip_free(za);
 		set_error(zep, NULL, ZIP_ER_MEMORY);
 		return NULL;
 	    }
 	    return za;
 	}
 	else {
 	    set_error(zep, NULL, ZIP_ER_OPEN);
 	    return NULL;
 	}
     }
     else if ((flags & ZIP_EXCL)) {
 	set_error(zep, NULL, ZIP_ER_EXISTS);
 	return NULL;
     }
     /* ZIP_CREATE gets ignored if file exists and not ZIP_EXCL,
        just like open() */

     if ((fp=fopen(fn, "rb")) == NULL) {
 	set_error(zep, NULL, ZIP_ER_OPEN);
 	return NULL;
     }

     clearerr(fp);
     fseek(fp, 0, SEEK_END);
     len = ftell(fp);
     i = fseek(fp, -(len < CDBUFSIZE ? len : CDBUFSIZE), SEEK_END);
     if (i == -1 && errno != EFBIG) {
 	/* seek before start of file on my machine */
 	set_error(zep, NULL, ZIP_ER_SEEK);
 	fclose(fp);
 	return NULL;
     }

     /* 64k is too much for stack */
     if ((buf=(unsigned char *)malloc(CDBUFSIZE)) == NULL) {
 	set_error(zep, NULL, ZIP_ER_MEMORY);
 	fclose(fp);
 	return NULL;
     }

     clearerr(fp);
     buflen = fread(buf, 1, CDBUFSIZE, fp);

     if (ferror(fp)) {
 	set_error(zep, NULL, ZIP_ER_READ);
 	free(buf);
 	fclose(fp);
 	return NULL;
     }

     best = -1;
     cdir = NULL;
     match = buf;
     while ((match=_zip_memmem(match, buflen-(match-buf)-18,
 			      EOCD_MAGIC, 4))!=NULL) {
 	/* found match -- check, if good */
 	/* to avoid finding the same match all over again */
 	match++;
 	if ((cdirnew=_zip_readcdir(fp, buf, match-1, buflen, &err2)) == NULL)
 	    continue;

 	if (cdir) {
 	    if (best <= 0)
 		best = _zip_checkcons(fp, cdir, &err2);
 	    a = _zip_checkcons(fp, cdirnew, &err2);
 	    if (best < a) {
 		_zip_cdir_free(cdir);
 		cdir = cdirnew;
 		best = a;
 	    }
 	    else
 		_zip_cdir_free(cdirnew);
 	}
 	else {
 	    cdir = cdirnew;
 	    if (flags & ZIP_CHECKCONS)
 		best = _zip_checkcons(fp, cdir, &err2);
 	    else
 		best = 0;
 	}
 	cdirnew = NULL;
     }

     free(buf);

     if (best < 0) {
 	/* no consistent eocd found */
 	set_error(zep, NULL, ZIP_ER_NOZIP);
 	_zip_cdir_free(cdir);
 	fclose(fp);
 	return NULL;
     }

     if ((za=_zip_new(&error)) == NULL) {
 	set_error(zep, &error, 0);
 	_zip_cdir_free(cdir);
 	fclose(fp);
 	return NULL;
     }

     za->zp = fp;
     za->cdir = cdir;

     if ((za->zn=strdup(fn)) == NULL) {
 	set_error(zep, NULL, ZIP_ER_MEMORY);
 	_zip_free(za);
 	return NULL;
     }

     if ((za->entry=malloc(sizeof(*(za->entry))*cdir->nentry)) == NULL) {
 	set_error(zep, NULL, ZIP_ER_MEMORY);
 	_zip_free(za);
 	return NULL;
     }
     for (i=0; i<cdir->nentry; i++)
 	_zip_new_entry(za);

     return za;
 }


 static void
 set_error(int *zep, struct zip_error *err, int ze)
 {
     int se;

     if (err) {
 	_zip_error_get(err, &ze, &se);
 	if (zip_error_sys_type(ze) == ZIP_ET_SYS)
 	    errno = se;
     }

     if (zep)
 	*zep = ze;
 }


 /* _zip_readcdir:
    tries to find a valid end-of-central-directory at the beginning of
    buf, and then the corresponding central directory entries.
    Returns a struct zip_cdir which contains the central directory
    entries, or NULL if unsuccessful. */

 static struct zip_cdir *
 _zip_readcdir(FILE *fp, unsigned char *buf, unsigned char *eocd, int buflen,
 	      struct zip_error *error)
 {
     struct zip_cdir *cd;
     unsigned char *cdp, **bufp;
     int i, comlen, nentry;

     comlen = buf + buflen - eocd - EOCDLEN;
     if (comlen < 0) {
 	/* not enough bytes left for comment */
 	_zip_error_set(error, ZIP_ER_NOZIP, 0);
 	return NULL;
     }

     /* check for end-of-central-dir magic */
     if (memcmp(eocd, EOCD_MAGIC, 4) != 0) {
 	_zip_error_set(error, ZIP_ER_NOZIP, 0);
 	return NULL;
     }

     if (memcmp(eocd+4, "\0\0\0\0", 4) != 0) {
 	_zip_error_set(error, ZIP_ER_MULTIDISK, 0);
 	return NULL;
     }

     cdp = eocd + 8;
     /* number of cdir-entries on this disk */
     i = _zip_read2(&cdp);
     /* number of cdir-entries */
     nentry = _zip_read2(&cdp);

     if ((cd=_zip_cdir_new(nentry, error)) == NULL)
 	return NULL;

     cd->size = _zip_read4(&cdp);
     cd->offset = _zip_read4(&cdp);
     cd->comment = NULL;
     cd->comment_len = _zip_read2(&cdp);

     /* XXX: some zip files are broken; their internal comment length
        says 0, but they have 1 or 2 comment bytes */
     if ((comlen-cd->comment_len < 0) || (comlen-cd->comment_len > 2)
 	|| (cd->nentry != i)) {
 	/* comment size wrong -- too few or too many left after central dir */
 	/* or number of cdir-entries on this disk != number of cdir-entries */
 	_zip_error_set(error, ZIP_ER_NOZIP, 0);
 	free(cd);
 	return NULL;
     }

     if (cd->comment_len)
 	cd->comment = _zip_memdup(eocd+EOCDLEN, cd->comment_len);

     cdp = eocd;
     if (cd->size < eocd-buf) {
 	/* if buffer already read in, use it */
 	cdp = eocd - cd->size;
 	bufp = &cdp;
     }
     else {
 	/* go to start of cdir and read it entry by entry */
 	bufp = NULL;
 	clearerr(fp);
 	fseek(fp, -(cd->size+cd->comment_len+EOCDLEN), SEEK_END);
 	if (ferror(fp) || (ftell(fp) != cd->offset)) {
 	    /* seek error or offset of cdir wrong */
 	    if (ferror(fp))
 		_zip_error_set(error, ZIP_ER_SEEK, errno);
 	    else
 		_zip_error_set(error, ZIP_ER_NOZIP, 0);
 	    free(cd);
 	    return NULL;
 	}
     }

     for (i=0; i<cd->nentry; i++) {
 	if ((_zip_dirent_read(cd->entry+i, fp, bufp, eocd-cdp, 0,
 			      error)) < 0) {
 	    cd->nentry = i;
 	    _zip_cdir_free(cd);
 	    return NULL;
 	}
     }

     return cd;
 }


 /* _zip_checkcons:
    Checks the consistency of the central directory by comparing central
    directory entries with local headers and checking for plausible
    file and header offsets. Returns -1 if not plausible, else the
    difference between the lowest and the highest fileposition reached */

 static int
 _zip_checkcons(FILE *fp, struct zip_cdir *cd, struct zip_error *error)
 {
     int min, max, i, j;
     struct zip_dirent temp;
     unsigned char *buf;

     buf = NULL;
     if (cd->nentry) {
 	max = cd->entry[0].offset;
 	min = cd->entry[0].offset;
     }

     for (i=0; i<cd->nentry; i++) {
 	if (cd->entry[i].offset < min)
 	    min = cd->entry[i].offset;
 	if (min < 0) {
 	    _zip_error_set(error, ZIP_ER_NOZIP, 0);
 	    return -1;
 	}

 	j = cd->entry[i].offset + cd->entry[i].comp_size
 	    + cd->entry[i].filename_len + LENTRYSIZE;
 	if (j > max)
 	    max = j;
 	if (max > cd->offset) {
 	    _zip_error_set(error, ZIP_ER_NOZIP, 0);
 	    return -1;
 	}

 	if (fseek(fp, cd->entry[i].offset, SEEK_SET) != 0) {
 	    _zip_error_set(error, ZIP_ER_SEEK, 0);
 	    return -1;
 	}

 	if (_zip_dirent_read(&temp, fp, NULL, 0, 1, error) == -1)
 	    return -1;

 	if (_zip_headercomp(cd->entry+i, 0, &temp, 1) != 0) {
 	    _zip_error_set(error, ZIP_ER_NOZIP, 0);
 	    _zip_dirent_finalize(&temp);
 	    return -1;
 	}
 	_zip_dirent_finalize(&temp);
     }

     return max - min;
 }


 /* _zip_headercomp:
    compares two headers h1 and h2; if they are local headers, set
    local1p or local2p respectively to 1, else 0. Return 0 if they
    are identical, -1 if not. */

 static int
 _zip_headercomp(struct zip_dirent *h1, int local1p, struct zip_dirent *h2,
 	   int local2p)
 {
     if ((h1->version_needed != h2->version_needed)
 #if 0
 	/* some zip-files have different values in local
 	   and global headers for the bitflags */
 	|| (h1->bitflags != h2->bitflags)
 #endif
 	|| (h1->comp_method != h2->comp_method)
 	|| (h1->last_mod != h2->last_mod)
 	|| (h1->crc != h2->crc)
 	|| (h1->comp_size != h2->comp_size)
 	|| (h1->uncomp_size != h2->uncomp_size)
 	|| (h1->filename_len != h2->filename_len)
 	|| !h1->filename || !h2->filename
 	|| strcmp(h1->filename, h2->filename))
 	return -1;

     if ((local1p == local2p)
 	&& ((h1->extrafield_len != h2->extrafield_len)
 	    || (h1->extrafield_len && h2->extrafield
 		&& memcmp(h1->extrafield, h2->extrafield,
 			  h1->extrafield_len))))
 	return -1;

     /* if either is local, nothing more to check */
     if (local1p || local2p)
 	return 0;

     if ((h1->version_madeby != h2->version_madeby)
 	|| (h1->disk_number != h2->disk_number)
 	|| (h1->int_attrib != h2->int_attrib)
 	|| (h1->ext_attrib != h2->ext_attrib)
 	|| (h1->offset != h2->offset)
 	|| (h1->comment_len != h2->comment_len)
 	|| (h1->comment_len && h2->comment
 	    && memcmp(h1->comment, h2->comment, h1->comment_len)))
 	return -1;

     return 0;
 }


 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=memchr(p+1, little[0], big-(p+1)+biglen-littlelen+1))!=NULL) {
 	if (memcmp(p+1, little+1, littlelen-1)==0)
 	    return (unsigned char *)p;
     }

     return NULL;
 }


 void *
 _zip_memdup(const void *mem, int len)
 {
     void *ret;

     ret = malloc(len);
     if (!ret) {
 	/* XXX: zip_err = ZIP_ER_MEMORY; */
 	return NULL;
     }

     memcpy(ret, mem, len);

     return ret;
 }
	/*
	$NiH: zip_open.c,v 1.22 2004/04/19 11:49:13 dillo Exp $

	zip_open.c -- open zip archive
	Copyright (C) 1999, 2003, 2004 Dieter Baron and Thomas Klausner

	This file is part of libzip, a library to manipulate ZIP archives.
	The authors can be contacted at <nih@giga.or.at>

	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.
	3. The names of the authors may not be used to endorse or promote
	products derived from this software without specific prior
	written permission.

	THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``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 AUTHORS 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 <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <errno.h>
	#include <unistd.h>
	#include <sys/types.h>
	#include <sys/stat.h>

	#include "zip.h"
	#include "zipint.h"

	static void set_error(int , struct zip_error , int);
	static int _zip_checkcons(FILE , struct zip_cdir , struct zip_error *);
	static int _zip_headercomp(struct zip_dirent *, int,
	struct zip_dirent *, int);
	static unsigned char _zip_memmem(const unsigned char , int,
	const unsigned char *, int);
	static struct zip_cdir _zip_readcdir(FILE , unsigned char , unsigned char ,
	int, struct zip_error *);



	struct zip *
	zip_open(const char fn, int flags, int zep)
	{
	FILE *fp;
	unsigned char buf, match;
	int a, i, buflen, best;
	struct zip *za;
	struct zip_cdir cdir, cdirnew;
	long len;
	struct stat st;
	struct zip_error error, err2;

	if (fn == NULL) {
	set_error(zep, NULL, ZIP_ER_INVAL);
	return NULL;
	}

	if (stat(fn, &st) != 0) {
	if (flags & ZIP_CREATE) {
	if ((za=_zip_new(&error)) == NULL) {
	set_error(zep, &error, 0);
	return NULL;
	}

	za->zn = strdup(fn);
	if (!za->zn) {
	_zip_free(za);
	set_error(zep, NULL, ZIP_ER_MEMORY);
	return NULL;
	}
	return za;
	}
	else {
	set_error(zep, NULL, ZIP_ER_OPEN);
	return NULL;
	}
	}
	else if ((flags & ZIP_EXCL)) {
	set_error(zep, NULL, ZIP_ER_EXISTS);
	return NULL;
	}
	/* ZIP_CREATE gets ignored if file exists and not ZIP_EXCL,
	just like open() */

	if ((fp=fopen(fn, "rb")) == NULL) {
	set_error(zep, NULL, ZIP_ER_OPEN);
	return NULL;
	}

	clearerr(fp);
	fseek(fp, 0, SEEK_END);
	len = ftell(fp);
	i = fseek(fp, -(len < CDBUFSIZE ? len : CDBUFSIZE), SEEK_END);
	if (i == -1 && errno != EFBIG) {
	/* seek before start of file on my machine */
	set_error(zep, NULL, ZIP_ER_SEEK);
	fclose(fp);
	return NULL;
	}

	/* 64k is too much for stack */
	if ((buf=(unsigned char *)malloc(CDBUFSIZE)) == NULL) {
	set_error(zep, NULL, ZIP_ER_MEMORY);
	fclose(fp);
	return NULL;
	}

	clearerr(fp);
	buflen = fread(buf, 1, CDBUFSIZE, fp);

	if (ferror(fp)) {
	set_error(zep, NULL, ZIP_ER_READ);
	free(buf);
	fclose(fp);
	return NULL;
	}

	best = -1;
	cdir = NULL;
	match = buf;
	while ((match=_zip_memmem(match, buflen-(match-buf)-18,
	EOCD_MAGIC, 4))!=NULL) {
	/* found match -- check, if good */
	/* to avoid finding the same match all over again */
	match++;
	if ((cdirnew=_zip_readcdir(fp, buf, match-1, buflen, &err2)) == NULL)
	continue;

	if (cdir) {
	if (best <= 0)
	best = _zip_checkcons(fp, cdir, &err2);
	a = _zip_checkcons(fp, cdirnew, &err2);
	if (best < a) {
	_zip_cdir_free(cdir);
	cdir = cdirnew;
	best = a;
	}
	else
	_zip_cdir_free(cdirnew);
	}
	else {
	cdir = cdirnew;
	if (flags & ZIP_CHECKCONS)
	best = _zip_checkcons(fp, cdir, &err2);
	else
	best = 0;
	}
	cdirnew = NULL;
	}

	free(buf);

	if (best < 0) {
	/* no consistent eocd found */
	set_error(zep, NULL, ZIP_ER_NOZIP);
	_zip_cdir_free(cdir);
	fclose(fp);
	return NULL;
	}

	if ((za=_zip_new(&error)) == NULL) {
	set_error(zep, &error, 0);
	_zip_cdir_free(cdir);
	fclose(fp);
	return NULL;
	}

	za->zp = fp;
	za->cdir = cdir;

	if ((za->zn=strdup(fn)) == NULL) {
	set_error(zep, NULL, ZIP_ER_MEMORY);
	_zip_free(za);
	return NULL;
	}

	if ((za->entry=malloc(sizeof((za->entry))cdir->nentry)) == NULL) {
	set_error(zep, NULL, ZIP_ER_MEMORY);
	_zip_free(za);
	return NULL;
	}
	for (i=0; i<cdir->nentry; i++)
	_zip_new_entry(za);

	return za;
	}



	static void
	set_error(int zep, struct zip_error err, int ze)
	{
	int se;

	if (err) {
	_zip_error_get(err, &ze, &se);
	if (zip_error_sys_type(ze) == ZIP_ET_SYS)
	errno = se;
	}

	if (zep)
	*zep = ze;
	}



	/* _zip_readcdir:
	tries to find a valid end-of-central-directory at the beginning of
	buf, and then the corresponding central directory entries.
	Returns a struct zip_cdir which contains the central directory
	entries, or NULL if unsuccessful. */

	static struct zip_cdir *
	_zip_readcdir(FILE fp, unsigned char buf, unsigned char *eocd, int buflen,
	struct zip_error *error)
	{
	struct zip_cdir *cd;
	unsigned char cdp, *bufp;
	int i, comlen, nentry;

	comlen = buf + buflen - eocd - EOCDLEN;
	if (comlen < 0) {
	/* not enough bytes left for comment */
	_zip_error_set(error, ZIP_ER_NOZIP, 0);
	return NULL;
	}

	/* check for end-of-central-dir magic */
	if (memcmp(eocd, EOCD_MAGIC, 4) != 0) {
	_zip_error_set(error, ZIP_ER_NOZIP, 0);
	return NULL;
	}

	if (memcmp(eocd+4, "\0\0\0\0", 4) != 0) {
	_zip_error_set(error, ZIP_ER_MULTIDISK, 0);
	return NULL;
	}

	cdp = eocd + 8;
	/* number of cdir-entries on this disk */
	i = _zip_read2(&cdp);
	/* number of cdir-entries */
	nentry = _zip_read2(&cdp);

	if ((cd=_zip_cdir_new(nentry, error)) == NULL)
	return NULL;

	cd->size = _zip_read4(&cdp);
	cd->offset = _zip_read4(&cdp);
	cd->comment = NULL;
	cd->comment_len = _zip_read2(&cdp);

	/* XXX: some zip files are broken; their internal comment length
	says 0, but they have 1 or 2 comment bytes */
	if ((comlen-cd->comment_len < 0) \|\| (comlen-cd->comment_len > 2)
	\|\| (cd->nentry != i)) {
	/* comment size wrong -- too few or too many left after central dir */
	/* or number of cdir-entries on this disk != number of cdir-entries */
	_zip_error_set(error, ZIP_ER_NOZIP, 0);
	free(cd);
	return NULL;
	}

	if (cd->comment_len)
	cd->comment = _zip_memdup(eocd+EOCDLEN, cd->comment_len);

	cdp = eocd;
	if (cd->size < eocd-buf) {
	/* if buffer already read in, use it */
	cdp = eocd - cd->size;
	bufp = &cdp;
	}
	else {
	/* go to start of cdir and read it entry by entry */
	bufp = NULL;
	clearerr(fp);
	fseek(fp, -(cd->size+cd->comment_len+EOCDLEN), SEEK_END);
	if (ferror(fp) \|\| (ftell(fp) != cd->offset)) {
	/* seek error or offset of cdir wrong */
	if (ferror(fp))
	_zip_error_set(error, ZIP_ER_SEEK, errno);
	else
	_zip_error_set(error, ZIP_ER_NOZIP, 0);
	free(cd);
	return NULL;
	}
	}

	for (i=0; i<cd->nentry; i++) {
	if ((_zip_dirent_read(cd->entry+i, fp, bufp, eocd-cdp, 0,
	error)) < 0) {
	cd->nentry = i;
	_zip_cdir_free(cd);
	return NULL;
	}
	}

	return cd;
	}



	/* _zip_checkcons:
	Checks the consistency of the central directory by comparing central
	directory entries with local headers and checking for plausible
	file and header offsets. Returns -1 if not plausible, else the
	difference between the lowest and the highest fileposition reached */

	static int
	_zip_checkcons(FILE fp, struct zip_cdir cd, struct zip_error *error)
	{
	int min, max, i, j;
	struct zip_dirent temp;
	unsigned char *buf;

	buf = NULL;
	if (cd->nentry) {
	max = cd->entry[0].offset;
	min = cd->entry[0].offset;
	}

	for (i=0; i<cd->nentry; i++) {
	if (cd->entry[i].offset < min)
	min = cd->entry[i].offset;
	if (min < 0) {
	_zip_error_set(error, ZIP_ER_NOZIP, 0);
	return -1;
	}

	j = cd->entry[i].offset + cd->entry[i].comp_size
	+ cd->entry[i].filename_len + LENTRYSIZE;
	if (j > max)
	max = j;
	if (max > cd->offset) {
	_zip_error_set(error, ZIP_ER_NOZIP, 0);
	return -1;
	}

	if (fseek(fp, cd->entry[i].offset, SEEK_SET) != 0) {
	_zip_error_set(error, ZIP_ER_SEEK, 0);
	return -1;
	}

	if (_zip_dirent_read(&temp, fp, NULL, 0, 1, error) == -1)
	return -1;

	if (_zip_headercomp(cd->entry+i, 0, &temp, 1) != 0) {
	_zip_error_set(error, ZIP_ER_NOZIP, 0);
	_zip_dirent_finalize(&temp);
	return -1;
	}
	_zip_dirent_finalize(&temp);
	}

	return max - min;
	}



	/* _zip_headercomp:
	compares two headers h1 and h2; if they are local headers, set
	local1p or local2p respectively to 1, else 0. Return 0 if they
	are identical, -1 if not. */

	static int
	_zip_headercomp(struct zip_dirent h1, int local1p, struct zip_dirent h2,
	int local2p)
	{
	if ((h1->version_needed != h2->version_needed)
	#if 0
	/* some zip-files have different values in local
	and global headers for the bitflags */
	\|\| (h1->bitflags != h2->bitflags)
	#endif
	\|\| (h1->comp_method != h2->comp_method)
	\|\| (h1->last_mod != h2->last_mod)
	\|\| (h1->crc != h2->crc)
	\|\| (h1->comp_size != h2->comp_size)
	\|\| (h1->uncomp_size != h2->uncomp_size)
	\|\| (h1->filename_len != h2->filename_len)
	\|\| !h1->filename \|\| !h2->filename
	\|\| strcmp(h1->filename, h2->filename))
	return -1;

	if ((local1p == local2p)
	&& ((h1->extrafield_len != h2->extrafield_len)
	\|\| (h1->extrafield_len && h2->extrafield
	&& memcmp(h1->extrafield, h2->extrafield,
	h1->extrafield_len))))
	return -1;

	/* if either is local, nothing more to check */
	if (local1p \|\| local2p)
	return 0;

	if ((h1->version_madeby != h2->version_madeby)
	\|\| (h1->disk_number != h2->disk_number)
	\|\| (h1->int_attrib != h2->int_attrib)
	\|\| (h1->ext_attrib != h2->ext_attrib)
	\|\| (h1->offset != h2->offset)
	\|\| (h1->comment_len != h2->comment_len)
	\|\| (h1->comment_len && h2->comment
	&& memcmp(h1->comment, h2->comment, h1->comment_len)))
	return -1;

	return 0;
	}



	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=memchr(p+1, little[0], big-(p+1)+biglen-littlelen+1))!=NULL) {
	if (memcmp(p+1, little+1, littlelen-1)==0)
	return (unsigned char *)p;
	}

	return NULL;
	}



	void *
	_zip_memdup(const void *mem, int len)
	{
	void *ret;

	ret = malloc(len);
	if (!ret) {
	/* XXX: zip_err = ZIP_ER_MEMORY; */
	return NULL;
	}

	memcpy(ret, mem, len);

	return ret;
	}