tools/ziptime/ZipFile.cpp - platform/build - Git at Google

 /*
  * Copyright (C) 2006 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 //
 // Access to Zip archives.
 //

 #include "ZipFile.h"

 #include <memory.h>
 #include <sys/stat.h>
 #include <errno.h>
 #include <assert.h>
 #include <inttypes.h>

 using namespace android;

 #define LOG(...) fprintf(stderr, __VA_ARGS__)

 /*
  * Open a file and rewrite the headers
  */
 status_t ZipFile::rewrite(const char* zipFileName)
 {
     assert(mZipFp == NULL);     // no reopen

     /* open the file */
     mZipFp = fopen(zipFileName, "r+b");
     if (mZipFp == NULL) {
         int err = errno;
         LOG("fopen failed: %d\n", err);
         return -1;
     }

     /*
      * Load the central directory.  If that fails, then this probably
      * isn't a Zip archive.
      */
     return rewriteCentralDir();
 }

 /*
  * Find the central directory, read and rewrite the contents.
  *
  * The fun thing about ZIP archives is that they may or may not be
  * readable from start to end.  In some cases, notably for archives
  * that were written to stdout, the only length information is in the
  * central directory at the end of the file.
  *
  * Of course, the central directory can be followed by a variable-length
  * comment field, so we have to scan through it backwards.  The comment
  * is at most 64K, plus we have 18 bytes for the end-of-central-dir stuff
  * itself, plus apparently sometimes people throw random junk on the end
  * just for the fun of it.
  *
  * This is all a little wobbly.  If the wrong value ends up in the EOCD
  * area, we're hosed.  This appears to be the way that everbody handles
  * it though, so we're in pretty good company if this fails.
  */
 status_t ZipFile::rewriteCentralDir(void)
 {
     status_t result = 0;
     uint8_t* buf = NULL;
     off_t fileLength, seekStart;
     long readAmount;
     int i;

     fseek(mZipFp, 0, SEEK_END);
     fileLength = ftell(mZipFp);
     rewind(mZipFp);

     /* too small to be a ZIP archive? */
     if (fileLength < EndOfCentralDir::kEOCDLen) {
         LOG("Length is %ld -- too small\n", (long)fileLength);
         result = -1;
         goto bail;
     }

     buf = new uint8_t[EndOfCentralDir::kMaxEOCDSearch];
     if (buf == NULL) {
         LOG("Failure allocating %d bytes for EOCD search",
              EndOfCentralDir::kMaxEOCDSearch);
         result = -1;
         goto bail;
     }

     if (fileLength > EndOfCentralDir::kMaxEOCDSearch) {
         seekStart = fileLength - EndOfCentralDir::kMaxEOCDSearch;
         readAmount = EndOfCentralDir::kMaxEOCDSearch;
     } else {
         seekStart = 0;
         readAmount = (long) fileLength;
     }
     if (fseek(mZipFp, seekStart, SEEK_SET) != 0) {
         LOG("Failure seeking to end of zip at %ld", (long) seekStart);
         result = -1;
         goto bail;
     }

     /* read the last part of the file into the buffer */
     if (fread(buf, 1, readAmount, mZipFp) != (size_t) readAmount) {
         LOG("short file? wanted %ld\n", readAmount);
         result = -1;
         goto bail;
     }

     /* find the end-of-central-dir magic */
     for (i = readAmount - 4; i >= 0; i--) {
         if (buf[i] == 0x50 &&
             ZipEntry::getLongLE(&buf[i]) == EndOfCentralDir::kSignature)
         {
             break;
         }
     }
     if (i < 0) {
         LOG("EOCD not found, not Zip\n");
         result = -1;
         goto bail;
     }

     /* extract eocd values */
     result = mEOCD.readBuf(buf + i, readAmount - i);
     if (result != 0) {
         LOG("Failure reading %ld bytes of EOCD values", readAmount - i);
         goto bail;
     }

     /*
      * So far so good.  "mCentralDirSize" is the size in bytes of the
      * central directory, so we can just seek back that far to find it.
      * We can also seek forward mCentralDirOffset bytes from the
      * start of the file.
      *
      * We're not guaranteed to have the rest of the central dir in the
      * buffer, nor are we guaranteed that the central dir will have any
      * sort of convenient size.  We need to skip to the start of it and
      * read the header, then the other goodies.
      *
      * The only thing we really need right now is the file comment, which
      * we're hoping to preserve.
      */
     if (fseek(mZipFp, mEOCD.mCentralDirOffset, SEEK_SET) != 0) {
         LOG("Failure seeking to central dir offset %" PRIu32 "\n",
              mEOCD.mCentralDirOffset);
         result = -1;
         goto bail;
     }

     /*
      * Loop through and read the central dir entries.
      */
     int entry;
     for (entry = 0; entry < mEOCD.mTotalNumEntries; entry++) {
         ZipEntry* pEntry = new ZipEntry;

         result = pEntry->initAndRewriteFromCDE(mZipFp);
         if (result != 0) {
             LOG("initFromCDE failed\n");
             delete pEntry;
             goto bail;
         }

         delete pEntry;
     }


     /*
      * If all went well, we should now be back at the EOCD.
      */
     uint8_t checkBuf[4];
     if (fread(checkBuf, 1, 4, mZipFp) != 4) {
         LOG("EOCD check read failed\n");
         result = -1;
         goto bail;
     }
     if (ZipEntry::getLongLE(checkBuf) != EndOfCentralDir::kSignature) {
         LOG("EOCD read check failed\n");
         result = -1;
         goto bail;
     }

 bail:
     delete[] buf;
     return result;
 }

 /*
  * ===========================================================================
  *      ZipFile::EndOfCentralDir
  * ===========================================================================
  */

 /*
  * Read the end-of-central-dir fields.
  *
  * "buf" should be positioned at the EOCD signature, and should contain
  * the entire EOCD area including the comment.
  */
 status_t ZipFile::EndOfCentralDir::readBuf(const uint8_t* buf, int len)
 {
     uint16_t diskNumber, diskWithCentralDir, numEntries;

     if (len < kEOCDLen) {
         /* looks like ZIP file got truncated */
         LOG(" Zip EOCD: expected >= %d bytes, found %d\n",
             kEOCDLen, len);
         return -1;
     }

     /* this should probably be an assert() */
     if (ZipEntry::getLongLE(&buf[0x00]) != kSignature)
         return -1;

     diskNumber = ZipEntry::getShortLE(&buf[0x04]);
     diskWithCentralDir = ZipEntry::getShortLE(&buf[0x06]);
     numEntries = ZipEntry::getShortLE(&buf[0x08]);
     mTotalNumEntries = ZipEntry::getShortLE(&buf[0x0a]);
     mCentralDirOffset = ZipEntry::getLongLE(&buf[0x10]);

     if (diskNumber != 0 || diskWithCentralDir != 0 ||
         numEntries != mTotalNumEntries)
     {
         LOG("Archive spanning not supported\n");
         return -1;
     }

     return 0;
 }
	/*
	* Copyright (C) 2006 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	//
	// Access to Zip archives.
	//

	#include "ZipFile.h"

	#include <memory.h>
	#include <sys/stat.h>
	#include <errno.h>
	#include <assert.h>
	#include <inttypes.h>

	using namespace android;

	#define LOG(...) fprintf(stderr, __VA_ARGS__)

	/*
	* Open a file and rewrite the headers
	*/
	status_t ZipFile::rewrite(const char* zipFileName)
	{
	assert(mZipFp == NULL); // no reopen

	/* open the file */
	mZipFp = fopen(zipFileName, "r+b");
	if (mZipFp == NULL) {
	int err = errno;
	LOG("fopen failed: %d\n", err);
	return -1;
	}

	/*
	* Load the central directory. If that fails, then this probably
	* isn't a Zip archive.
	*/
	return rewriteCentralDir();
	}

	/*
	* Find the central directory, read and rewrite the contents.
	*
	* The fun thing about ZIP archives is that they may or may not be
	* readable from start to end. In some cases, notably for archives
	* that were written to stdout, the only length information is in the
	* central directory at the end of the file.
	*
	* Of course, the central directory can be followed by a variable-length
	* comment field, so we have to scan through it backwards. The comment
	* is at most 64K, plus we have 18 bytes for the end-of-central-dir stuff
	* itself, plus apparently sometimes people throw random junk on the end
	* just for the fun of it.
	*
	* This is all a little wobbly. If the wrong value ends up in the EOCD
	* area, we're hosed. This appears to be the way that everbody handles
	* it though, so we're in pretty good company if this fails.
	*/
	status_t ZipFile::rewriteCentralDir(void)
	{
	status_t result = 0;
	uint8_t* buf = NULL;
	off_t fileLength, seekStart;
	long readAmount;
	int i;

	fseek(mZipFp, 0, SEEK_END);
	fileLength = ftell(mZipFp);
	rewind(mZipFp);

	/* too small to be a ZIP archive? */
	if (fileLength < EndOfCentralDir::kEOCDLen) {
	LOG("Length is %ld -- too small\n", (long)fileLength);
	result = -1;
	goto bail;
	}

	buf = new uint8_t[EndOfCentralDir::kMaxEOCDSearch];
	if (buf == NULL) {
	LOG("Failure allocating %d bytes for EOCD search",
	EndOfCentralDir::kMaxEOCDSearch);
	result = -1;
	goto bail;
	}

	if (fileLength > EndOfCentralDir::kMaxEOCDSearch) {
	seekStart = fileLength - EndOfCentralDir::kMaxEOCDSearch;
	readAmount = EndOfCentralDir::kMaxEOCDSearch;
	} else {
	seekStart = 0;
	readAmount = (long) fileLength;
	}
	if (fseek(mZipFp, seekStart, SEEK_SET) != 0) {
	LOG("Failure seeking to end of zip at %ld", (long) seekStart);
	result = -1;
	goto bail;
	}

	/* read the last part of the file into the buffer */
	if (fread(buf, 1, readAmount, mZipFp) != (size_t) readAmount) {
	LOG("short file? wanted %ld\n", readAmount);
	result = -1;
	goto bail;
	}

	/* find the end-of-central-dir magic */
	for (i = readAmount - 4; i >= 0; i--) {
	if (buf[i] == 0x50 &&
	ZipEntry::getLongLE(&buf[i]) == EndOfCentralDir::kSignature)
	{
	break;
	}
	}
	if (i < 0) {
	LOG("EOCD not found, not Zip\n");
	result = -1;
	goto bail;
	}

	/* extract eocd values */
	result = mEOCD.readBuf(buf + i, readAmount - i);
	if (result != 0) {
	LOG("Failure reading %ld bytes of EOCD values", readAmount - i);
	goto bail;
	}

	/*
	* So far so good. "mCentralDirSize" is the size in bytes of the
	* central directory, so we can just seek back that far to find it.
	* We can also seek forward mCentralDirOffset bytes from the
	* start of the file.
	*
	* We're not guaranteed to have the rest of the central dir in the
	* buffer, nor are we guaranteed that the central dir will have any
	* sort of convenient size. We need to skip to the start of it and
	* read the header, then the other goodies.
	*
	* The only thing we really need right now is the file comment, which
	* we're hoping to preserve.
	*/
	if (fseek(mZipFp, mEOCD.mCentralDirOffset, SEEK_SET) != 0) {
	LOG("Failure seeking to central dir offset %" PRIu32 "\n",
	mEOCD.mCentralDirOffset);
	result = -1;
	goto bail;
	}

	/*
	* Loop through and read the central dir entries.
	*/
	int entry;
	for (entry = 0; entry < mEOCD.mTotalNumEntries; entry++) {
	ZipEntry* pEntry = new ZipEntry;

	result = pEntry->initAndRewriteFromCDE(mZipFp);
	if (result != 0) {
	LOG("initFromCDE failed\n");
	delete pEntry;
	goto bail;
	}

	delete pEntry;
	}


	/*
	* If all went well, we should now be back at the EOCD.
	*/
	uint8_t checkBuf[4];
	if (fread(checkBuf, 1, 4, mZipFp) != 4) {
	LOG("EOCD check read failed\n");
	result = -1;
	goto bail;
	}
	if (ZipEntry::getLongLE(checkBuf) != EndOfCentralDir::kSignature) {
	LOG("EOCD read check failed\n");
	result = -1;
	goto bail;
	}

	bail:
	delete[] buf;
	return result;
	}

	/*
	* ===========================================================================
	* ZipFile::EndOfCentralDir
	* ===========================================================================
	*/

	/*
	* Read the end-of-central-dir fields.
	*
	* "buf" should be positioned at the EOCD signature, and should contain
	* the entire EOCD area including the comment.
	*/
	status_t ZipFile::EndOfCentralDir::readBuf(const uint8_t* buf, int len)
	{
	uint16_t diskNumber, diskWithCentralDir, numEntries;

	if (len < kEOCDLen) {
	/* looks like ZIP file got truncated */
	LOG(" Zip EOCD: expected >= %d bytes, found %d\n",
	kEOCDLen, len);
	return -1;
	}

	/* this should probably be an assert() */
	if (ZipEntry::getLongLE(&buf[0x00]) != kSignature)
	return -1;

	diskNumber = ZipEntry::getShortLE(&buf[0x04]);
	diskWithCentralDir = ZipEntry::getShortLE(&buf[0x06]);
	numEntries = ZipEntry::getShortLE(&buf[0x08]);
	mTotalNumEntries = ZipEntry::getShortLE(&buf[0x0a]);
	mCentralDirOffset = ZipEntry::getLongLE(&buf[0x10]);

	if (diskNumber != 0 \|\| diskWithCentralDir != 0 \|\|
	numEntries != mTotalNumEntries)
	{
	LOG("Archive spanning not supported\n");
	return -1;
	}

	return 0;
	}