/*
* Copyright (C) 2007 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.
*/
//
// Misc zip/gzip utility functions.
//
#define LOG_TAG "ziputil"
#include <utils/ZipUtils.h>
#include <utils/ZipFileRO.h>
#include <utils/Log.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <zlib.h>
using namespace android;
/*
* Utility function that expands zip/gzip "deflate" compressed data
* into a buffer.
*
* "fd" is an open file positioned at the start of the "deflate" data
* "buf" must hold at least "uncompressedLen" bytes.
*/
/*static*/ bool ZipUtils::inflateToBuffer(int fd, void* buf,
long uncompressedLen, long compressedLen)
{
bool result = false;
const unsigned long kReadBufSize = 32768;
unsigned char* readBuf = NULL;
z_stream zstream;
int zerr;
unsigned long compRemaining;
assert(uncompressedLen >= 0);
assert(compressedLen >= 0);
readBuf = new unsigned char[kReadBufSize];
if (readBuf == NULL)
goto bail;
compRemaining = compressedLen;
/*
* Initialize the zlib stream.
*/
memset(&zstream, 0, sizeof(zstream));
zstream.zalloc = Z_NULL;
zstream.zfree = Z_NULL;
zstream.opaque = Z_NULL;
zstream.next_in = NULL;
zstream.avail_in = 0;
zstream.next_out = (Bytef*) buf;
zstream.avail_out = uncompressedLen;
zstream.data_type = Z_UNKNOWN;
/*
* Use the undocumented "negative window bits" feature to tell zlib
* that there's no zlib header waiting for it.
*/
zerr = inflateInit2(&zstream, -MAX_WBITS);
if (zerr != Z_OK) {
if (zerr == Z_VERSION_ERROR) {
LOGE("Installed zlib is not compatible with linked version (%s)\n",
ZLIB_VERSION);
} else {
LOGE("Call to inflateInit2 failed (zerr=%d)\n", zerr);
}
goto bail;
}
/*
* Loop while we have data.
*/
do {
unsigned long getSize;
/* read as much as we can */
if (zstream.avail_in == 0) {
getSize = (compRemaining > kReadBufSize) ?
kReadBufSize : compRemaining;
LOGV("+++ reading %ld bytes (%ld left)\n",
getSize, compRemaining);
int cc = read(fd, readBuf, getSize);
if (cc != (int) getSize) {
LOGD("inflate read failed (%d vs %ld)\n",
cc, getSize);
goto z_bail;
}
compRemaining -= getSize;
zstream.next_in = readBuf;
zstream.avail_in = getSize;
}
/* uncompress the data */
zerr = inflate(&zstream, Z_NO_FLUSH);
if (zerr != Z_OK && zerr != Z_STREAM_END) {
LOGD("zlib inflate call failed (zerr=%d)\n", zerr);
goto z_bail;
}
/* output buffer holds all, so no need to write the output */
} while (zerr == Z_OK);
assert(zerr == Z_STREAM_END); /* other errors should've been caught */
if ((long) zstream.total_out != uncompressedLen) {
LOGW("Size mismatch on inflated file (%ld vs %ld)\n",
zstream.total_out, uncompressedLen);
goto z_bail;
}
// success!
result = true;
z_bail:
inflateEnd(&zstream); /* free up any allocated structures */
bail:
delete[] readBuf;
return result;
}
/*
* Utility function that expands zip/gzip "deflate" compressed data
* into a buffer.
*
* (This is a clone of the previous function, but it takes a FILE* instead
* of an fd. We could pass fileno(fd) to the above, but we can run into
* trouble when "fp" has a different notion of what fd's file position is.)
*
* "fp" is an open file positioned at the start of the "deflate" data
* "buf" must hold at least "uncompressedLen" bytes.
*/
/*static*/ bool ZipUtils::inflateToBuffer(FILE* fp, void* buf,
long uncompressedLen, long compressedLen)
{
bool result = false;
const unsigned long kReadBufSize = 32768;
unsigned char* readBuf = NULL;
z_stream zstream;
int zerr;
unsigned long compRemaining;
assert(uncompressedLen >= 0);
assert(compressedLen >= 0);
readBuf = new unsigned char[kReadBufSize];
if (readBuf == NULL)
goto bail;
compRemaining = compressedLen;
/*
* Initialize the zlib stream.
*/
memset(&zstream, 0, sizeof(zstream));
zstream.zalloc = Z_NULL;
zstream.zfree = Z_NULL;
zstream.opaque = Z_NULL;
zstream.next_in = NULL;
zstream.avail_in = 0;
zstream.next_out = (Bytef*) buf;
zstream.avail_out = uncompressedLen;
zstream.data_type = Z_UNKNOWN;
/*
* Use the undocumented "negative window bits" feature to tell zlib
* that there's no zlib header waiting for it.
*/
zerr = inflateInit2(&zstream, -MAX_WBITS);
if (zerr != Z_OK) {
if (zerr == Z_VERSION_ERROR) {
LOGE("Installed zlib is not compatible with linked version (%s)\n",
ZLIB_VERSION);
} else {
LOGE("Call to inflateInit2 failed (zerr=%d)\n", zerr);
}
goto bail;
}
/*
* Loop while we have data.
*/
do {
unsigned long getSize;
/* read as much as we can */
if (zstream.avail_in == 0) {
getSize = (compRemaining > kReadBufSize) ?
kReadBufSize : compRemaining;
LOGV("+++ reading %ld bytes (%ld left)\n",
getSize, compRemaining);
int cc = fread(readBuf, 1, getSize, fp);
if (cc != (int) getSize) {
LOGD("inflate read failed (%d vs %ld)\n",
cc, getSize);
goto z_bail;
}
compRemaining -= getSize;
zstream.next_in = readBuf;
zstream.avail_in = getSize;
}
/* uncompress the data */
zerr = inflate(&zstream, Z_NO_FLUSH);
if (zerr != Z_OK && zerr != Z_STREAM_END) {
LOGD("zlib inflate call failed (zerr=%d)\n", zerr);
goto z_bail;
}
/* output buffer holds all, so no need to write the output */
} while (zerr == Z_OK);
assert(zerr == Z_STREAM_END); /* other errors should've been caught */
if ((long) zstream.total_out != uncompressedLen) {
LOGW("Size mismatch on inflated file (%ld vs %ld)\n",
zstream.total_out, uncompressedLen);
goto z_bail;
}
// success!
result = true;
z_bail:
inflateEnd(&zstream); /* free up any allocated structures */
bail:
delete[] readBuf;
return result;
}
/*
* Look at the contents of a gzip archive. We want to know where the
* data starts, and how long it will be after it is uncompressed.
*
* We expect to find the CRC and length as the last 8 bytes on the file.
* This is a pretty reasonable thing to expect for locally-compressed
* files, but there's a small chance that some extra padding got thrown
* on (the man page talks about compressed data written to tape). We
* don't currently deal with that here. If "gzip -l" whines, we're going
* to fail too.
*
* On exit, "fp" is pointing at the start of the compressed data.
*/
/*static*/ bool ZipUtils::examineGzip(FILE* fp, int* pCompressionMethod,
long* pUncompressedLen, long* pCompressedLen, unsigned long* pCRC32)
{
enum { // flags
FTEXT = 0x01,
FHCRC = 0x02,
FEXTRA = 0x04,
FNAME = 0x08,
FCOMMENT = 0x10,
};
int ic;
int method, flags;
int i;
ic = getc(fp);
if (ic != 0x1f || getc(fp) != 0x8b)
return false; // not gzip
method = getc(fp);
flags = getc(fp);
/* quick sanity checks */
if (method == EOF || flags == EOF)
return false;
if (method != ZipFileRO::kCompressDeflated)
return false;
/* skip over 4 bytes of mod time, 1 byte XFL, 1 byte OS */
for (i = 0; i < 6; i++)
(void) getc(fp);
/* consume "extra" field, if present */
if ((flags & FEXTRA) != 0) {
int len;
len = getc(fp);
len |= getc(fp) << 8;
while (len-- && getc(fp) != EOF)
;
}
/* consume filename, if present */
if ((flags & FNAME) != 0) {
do {
ic = getc(fp);
} while (ic != 0 && ic != EOF);
}
/* consume comment, if present */
if ((flags & FCOMMENT) != 0) {
do {
ic = getc(fp);
} while (ic != 0 && ic != EOF);
}
/* consume 16-bit header CRC, if present */
if ((flags & FHCRC) != 0) {
(void) getc(fp);
(void) getc(fp);
}
if (feof(fp) || ferror(fp))
return false;
/* seek to the end; CRC and length are in the last 8 bytes */
long curPosn = ftell(fp);
unsigned char buf[8];
fseek(fp, -8, SEEK_END);
*pCompressedLen = ftell(fp) - curPosn;
if (fread(buf, 1, 8, fp) != 8)
return false;
/* seek back to start of compressed data */
fseek(fp, curPosn, SEEK_SET);
*pCompressionMethod = method;
*pCRC32 = ZipFileRO::get4LE(&buf[0]);
*pUncompressedLen = ZipFileRO::get4LE(&buf[4]);
return true;
}