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// Copyright 2007 Alan Donovan. All rights reserved.
//
// Author: Alan Donovan <adonovan@google.com>
//
// 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.
//
// zip.cc -- .zip (.jar) file reading/writing routines.
//
// See README.txt for details.
//
// See http://www.pkware.com/documents/casestudies/APPNOTE.TXT
// for definition of PKZIP file format.
#define _FILE_OFFSET_BITS 64 // Support zip files larger than 2GB
#include <errno.h>
#include <fcntl.h>
#include <stddef.h>
#include <stdint.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <unistd.h>
#include <limits.h>
#include <limits>
#include <vector>
#include "zip.h"
#include <zlib.h>
#define LOCAL_FILE_HEADER_SIGNATURE 0x04034b50
#define CENTRAL_FILE_HEADER_SIGNATURE 0x02014b50
#define END_OF_CENTRAL_DIR_SIGNATURE 0x06054b50
#define DATA_DESCRIPTOR_SIGNATURE 0x08074b50
// version to extract: 1.0 - default value from APPNOTE.TXT.
// Output JAR files contain no extra ZIP features, so this is enough.
#define ZIP_VERSION_TO_EXTRACT 10
#define COMPRESSION_METHOD_STORED 0 // no compression
#define COMPRESSION_METHOD_DEFLATED 8
#define GENERAL_PURPOSE_BIT_FLAG_COMPRESSED (1 << 3)
#define GENERAL_PURPOSE_BIT_FLAG_UTF8_ENCODED (1 << 11)
#define GENERAL_PURPOSE_BIT_FLAG_COMPRESSION_SPEED ((1 << 2) | (1 << 1))
#define GENERAL_PURPOSE_BIT_FLAG_SUPPORTED \
(GENERAL_PURPOSE_BIT_FLAG_COMPRESSED \
| GENERAL_PURPOSE_BIT_FLAG_UTF8_ENCODED \
| GENERAL_PURPOSE_BIT_FLAG_COMPRESSION_SPEED)
namespace devtools_ijar {
// In the absence of ZIP64 support, zip files are limited to 4GB.
// http://www.info-zip.org/FAQ.html#limits
static const u8 kMaximumOutputSize = std::numeric_limits<uint32_t>::max();
static bool ProcessCentralDirEntry(const u1 *&p,
size_t *compressed_size,
size_t *uncompressed_size,
char *filename,
size_t filename_size,
u4 *attr,
u4 *offset);
//
// A class representing a ZipFile for reading. Its public API is exposed
// using the ZipExtractor abstract class.
//
class InputZipFile : public ZipExtractor {
public:
InputZipFile(ZipExtractorProcessor *processor, int fd, off_t in_length,
off_t in_offset, const u1* zipdata_in, const u1* central_dir);
virtual ~InputZipFile();
virtual const char* GetError() {
if (errmsg[0] == 0) {
return NULL;
}
return errmsg;
}
virtual bool ProcessNext();
virtual void Reset();
virtual size_t GetSize() {
return in_length_;
}
virtual u8 CalculateOutputLength();
private:
ZipExtractorProcessor *processor;
int fd_in; // Input file descripor
// InputZipFile is responsible for maintaining the following
// pointers. They are allocated by the Create() method before
// the object is actually created using mmap.
const u1 * const zipdata_in_; // start of input file mmap
const u1 * zipdata_in_mapped_; // start of still mapped region
const u1 * const central_dir_; // central directory in input file
size_t in_length_; // size of the input file
size_t in_offset_; // offset the input file
const u1 *p; // input cursor
const u1* central_dir_current_; // central dir input cursor
// Buffer size is initially INITIAL_BUFFER_SIZE. It doubles in size every
// time it is found too small, until it reaches MAX_BUFFER_SIZE. If that is
// not enough, we bail out. We only decompress class files, so they should
// be smaller than 64K anyway, but we give a little leeway.
// MAX_BUFFER_SIZE must be bigger than the size of the biggest file in the
// ZIP. It is set to 128M here so we can uncompress the Bazel server with
// this library.
static const size_t INITIAL_BUFFER_SIZE = 256 * 1024; // 256K
static const size_t MAX_BUFFER_SIZE = 128 * 1024 * 1024;
static const size_t MAX_MAPPED_REGION = 32 * 1024 * 1024;
// These metadata fields are the fields of the ZIP header of the file being
// processed.
u2 extract_version_;
u2 general_purpose_bit_flag_;
u2 compression_method_;
u4 uncompressed_size_;
u4 compressed_size_;
u2 file_name_length_;
u2 extra_field_length_;
const u1 *file_name_;
const u1 *extra_field_;
// Administration of memory reserved for decompressed data. We use the same
// buffer for each file to avoid some malloc()/free() calls and free the
// memory only in the dtor. C-style memory management is used so that we
// can call realloc.
u1 *uncompressed_data_;
size_t uncompressed_data_allocated_;
// Copy of the last filename entry - Null-terminated.
char filename[PATH_MAX];
// The external file attribute field
u4 attr;
// last error
char errmsg[4*PATH_MAX];
int error(const char *fmt, ...) {
va_list ap;
va_start(ap, fmt);
vsnprintf(errmsg, 4*PATH_MAX, fmt, ap);
va_end(ap);
return -1;
}
// Check that at least n bytes remain in the input file, otherwise
// abort with an error message. "state" is the name of the field
// we're about to read, for diagnostics.
int EnsureRemaining(size_t n, const char *state) {
size_t in_offset = p - zipdata_in_;
size_t remaining = in_length_ - in_offset;
if (n > remaining) {
return error("Premature end of file (at offset %zd, state=%s); "
"expected %zd more bytes but found %zd.\n",
in_offset, state, n, remaining);
}
return 0;
}
// Read one entry from input zip file
int ProcessLocalFileEntry(size_t compressed_size, size_t uncompressed_size);
// Uncompress a file from the archive using zlib. The pointer returned
// is owned by InputZipFile, so it must not be freed. Advances the input
// cursor to the first byte after the compressed data.
u1* UncompressFile();
// Skip a file
int SkipFile(const bool compressed);
// Process a file
int ProcessFile(const bool compressed);
};
//
// A class implementing ZipBuilder that represent an open zip file for writing.
//
class OutputZipFile : public ZipBuilder {
public:
OutputZipFile(int fd, u1 * const zipdata_out) :
fd_out(fd),
zipdata_out_(zipdata_out),
q(zipdata_out) {
errmsg[0] = 0;
}
virtual const char* GetError() {
if (errmsg[0] == 0) {
return NULL;
}
return errmsg;
}
virtual ~OutputZipFile() { Finish(); }
virtual u1* NewFile(const char* filename, const u4 attr);
virtual int FinishFile(size_t filelength, bool compress = false,
bool compute_crc = false);
virtual int WriteEmptyFile(const char *filename);
virtual size_t GetSize() {
return Offset(q);
}
virtual int GetNumberFiles() {
return entries_.size();
}
virtual int Finish();
private:
struct LocalFileEntry {
// Start of the local header (in the output buffer).
size_t local_header_offset;
// Sizes of the file entry
size_t uncompressed_length;
size_t compressed_length;
// Compression method
u2 compression_method;
// CRC32
u4 crc32;
// external attributes field
u4 external_attr;
// Start/length of the file_name in the local header.
u1 *file_name;
u2 file_name_length;
// Start/length of the extra_field in the local header.
const u1 *extra_field;
u2 extra_field_length;
};
int fd_out; // file descriptor for the output file
// OutputZipFile is responsible for maintaining the following
// pointers. They are allocated by the Create() method before
// the object is actually created using mmap.
u1 * const zipdata_out_; // start of output file mmap
u1 *q; // output cursor
u1 *header_ptr; // Current pointer to "compression method" entry.
// List of entries to write the central directory
std::vector<LocalFileEntry*> entries_;
// last error
char errmsg[4*PATH_MAX];
int error(const char *fmt, ...) {
va_list ap;
va_start(ap, fmt);
vsnprintf(errmsg, 4*PATH_MAX, fmt, ap);
va_end(ap);
return -1;
}
// Write the ZIP central directory structure for each local file
// entry in "entries".
void WriteCentralDirectory();
// Returns the offset of the pointer relative to the start of the
// output zip file.
size_t Offset(const u1 *const x) {
return x - zipdata_out_;
}
// Write ZIP file header in the output. Since the compressed size is not
// known in advance, it must be recorded later. This method returns a pointer
// to "compressed size" in the file header that should be passed to
// WriteFileSizeInLocalFileHeader() later.
u1* WriteLocalFileHeader(const char *filename, const u4 attr);
// Fill in the "compressed size" and "uncompressed size" fields in a local
// file header previously written by WriteLocalFileHeader().
size_t WriteFileSizeInLocalFileHeader(u1 *header_ptr,
size_t out_length,
bool compress = false,
const u4 crc = 0);
};
//
// Implementation of InputZipFile
//
bool InputZipFile::ProcessNext() {
// Process the next entry in the central directory. Also make sure that the
// content pointer is in sync.
size_t compressed, uncompressed;
u4 offset;
if (!ProcessCentralDirEntry(central_dir_current_, &compressed, &uncompressed,
filename, PATH_MAX, &attr, &offset)) {
return false;
}
// There might be an offset specified in the central directory that does
// not match the file offset, if so, correct the pointer.
if (offset != 0 && (p != (zipdata_in_ + in_offset_ + offset))) {
p = zipdata_in_ + offset;
}
if (EnsureRemaining(4, "signature") < 0) {
return false;
}
u4 signature = get_u4le(p);
if (signature == LOCAL_FILE_HEADER_SIGNATURE) {
if (ProcessLocalFileEntry(compressed, uncompressed) < 0) {
return false;
}
} else {
error("local file header signature for file %s not found\n", filename);
return false;
}
return true;
}
int InputZipFile::ProcessLocalFileEntry(
size_t compressed_size, size_t uncompressed_size) {
if (EnsureRemaining(26, "extract_version") < 0) {
return -1;
}
extract_version_ = get_u2le(p);
general_purpose_bit_flag_ = get_u2le(p);
if ((general_purpose_bit_flag_ & ~GENERAL_PURPOSE_BIT_FLAG_SUPPORTED) != 0) {
return error("Unsupported value (0x%04x) in general purpose bit flag.\n",
general_purpose_bit_flag_);
}
compression_method_ = get_u2le(p);
if (compression_method_ != COMPRESSION_METHOD_DEFLATED &&
compression_method_ != COMPRESSION_METHOD_STORED) {
return error("Unsupported compression method (%d).\n",
compression_method_);
}
// skip over: last_mod_file_time, last_mod_file_date, crc32
p += 2 + 2 + 4;
compressed_size_ = get_u4le(p);
uncompressed_size_ = get_u4le(p);
file_name_length_ = get_u2le(p);
extra_field_length_ = get_u2le(p);
if (EnsureRemaining(file_name_length_, "file_name") < 0) {
return -1;
}
file_name_ = p;
p += file_name_length_;
if (EnsureRemaining(extra_field_length_, "extra_field") < 0) {
return -1;
}
extra_field_ = p;
p += extra_field_length_;
bool is_compressed = compression_method_ == COMPRESSION_METHOD_DEFLATED;
// If the zip is compressed, compressed and uncompressed size members are
// zero in the local file header. If not, check that they are the same as the
// lengths from the central directory, otherwise, just believe the central
// directory
if (compressed_size_ == 0) {
compressed_size_ = compressed_size;
} else {
if (compressed_size_ != compressed_size) {
return error("central directory and file header inconsistent\n");
}
}
if (uncompressed_size_ == 0) {
uncompressed_size_ = uncompressed_size;
} else {
if (uncompressed_size_ != uncompressed_size) {
return error("central directory and file header inconsistent\n");
}
}
if (processor->Accept(filename, attr)) {
if (ProcessFile(is_compressed) < 0) {
return -1;
}
} else {
if (SkipFile(is_compressed) < 0) {
return -1;
}
}
if (general_purpose_bit_flag_ & GENERAL_PURPOSE_BIT_FLAG_COMPRESSED) {
// Skip the data descriptor. Some implementations do not put the signature
// here, so check if the next 4 bytes are a signature, and if so, skip the
// next 12 bytes (for CRC, compressed/uncompressed size), otherwise skip
// the next 8 bytes (because the value just read was the CRC).
u4 signature = get_u4le(p);
if (signature == DATA_DESCRIPTOR_SIGNATURE) {
p += 4 * 3;
} else {
p += 4 * 2;
}
}
if (p > zipdata_in_mapped_ + MAX_MAPPED_REGION) {
munmap(const_cast<u1 *>(zipdata_in_mapped_), MAX_MAPPED_REGION);
zipdata_in_mapped_ += MAX_MAPPED_REGION;
}
return 0;
}
int InputZipFile::SkipFile(const bool compressed) {
if (!compressed) {
// In this case, compressed_size_ == uncompressed_size_ (since the file is
// uncompressed), so we can use either.
if (compressed_size_ != uncompressed_size_) {
return error("compressed size != uncompressed size, although the file "
"is uncompressed.\n");
}
}
if (EnsureRemaining(compressed_size_, "file_data") < 0) {
return -1;
}
p += compressed_size_;
return 0;
}
u1* InputZipFile::UncompressFile() {
size_t in_offset = p - zipdata_in_;
size_t remaining = in_length_ - in_offset;
z_stream stream;
stream.zalloc = Z_NULL;
stream.zfree = Z_NULL;
stream.opaque = Z_NULL;
stream.avail_in = remaining;
stream.next_in = (Bytef *) p;
int ret = inflateInit2(&stream, -MAX_WBITS);
if (ret != Z_OK) {
error("inflateInit: %d\n", ret);
return NULL;
}
int uncompressed_until_now = 0;
while (true) {
stream.avail_out = uncompressed_data_allocated_ - uncompressed_until_now;
stream.next_out = uncompressed_data_ + uncompressed_until_now;
int old_avail_out = stream.avail_out;
ret = inflate(&stream, Z_SYNC_FLUSH);
int uncompressed_now = old_avail_out - stream.avail_out;
uncompressed_until_now += uncompressed_now;
switch (ret) {
case Z_STREAM_END: {
// zlib said that there is no more data to decompress.
u1 *new_p = reinterpret_cast<u1*>(stream.next_in);
compressed_size_ = new_p - p;
uncompressed_size_ = uncompressed_until_now;
p = new_p;
inflateEnd(&stream);
return uncompressed_data_;
}
case Z_OK: {
// zlib said that there is no more room in the buffer allocated for
// the decompressed data. Enlarge that buffer and try again.
if (uncompressed_data_allocated_ == MAX_BUFFER_SIZE) {
error("ijar does not support decompressing files "
"larger than %dMB.\n",
(int) (MAX_BUFFER_SIZE/(1024*1024)));
return NULL;
}
uncompressed_data_allocated_ *= 2;
if (uncompressed_data_allocated_ > MAX_BUFFER_SIZE) {
uncompressed_data_allocated_ = MAX_BUFFER_SIZE;
}
uncompressed_data_ = reinterpret_cast<u1*>(
realloc(uncompressed_data_, uncompressed_data_allocated_));
break;
}
case Z_DATA_ERROR:
case Z_BUF_ERROR:
case Z_STREAM_ERROR:
case Z_NEED_DICT:
default: {
error("zlib returned error code %d during inflate.\n", ret);
return NULL;
}
}
}
}
int InputZipFile::ProcessFile(const bool compressed) {
const u1 *file_data;
if (compressed) {
file_data = UncompressFile();
if (file_data == NULL) {
return -1;
}
} else {
// In this case, compressed_size_ == uncompressed_size_ (since the file is
// uncompressed), so we can use either.
if (compressed_size_ != uncompressed_size_) {
return error("compressed size != uncompressed size, although the file "
"is uncompressed.\n");
}
if (EnsureRemaining(compressed_size_, "file_data") < 0) {
return -1;
}
file_data = p;
p += compressed_size_;
}
processor->Process(filename, attr, file_data, uncompressed_size_);
return 0;
}
// Reads and returns some metadata of the next file from the central directory:
// - compressed size
// - uncompressed size
// - whether the entry is a class file (to be included in the output).
// Precondition: p points to the beginning of an entry in the central dir
// Postcondition: p points to the beginning of the next entry in the central dir
// Returns true if the central directory contains another file and false if not.
// Of course, in the latter case, the size output variables are not changed.
// Note that the central directory is always followed by another data structure
// that has a signature, so parsing it this way is safe.
static bool ProcessCentralDirEntry(
const u1 *&p, size_t *compressed_size, size_t *uncompressed_size,
char *filename, size_t filename_size, u4 *attr, u4 *offset) {
u4 signature = get_u4le(p);
if (signature != CENTRAL_FILE_HEADER_SIGNATURE) {
return false;
}
p += 16; // skip to 'compressed size' field
*compressed_size = get_u4le(p);
*uncompressed_size = get_u4le(p);
u2 file_name_length = get_u2le(p);
u2 extra_field_length = get_u2le(p);
u2 file_comment_length = get_u2le(p);
p += 4; // skip to external file attributes field
*attr = get_u4le(p);
*offset = get_u4le(p);
{
size_t len = (file_name_length < filename_size)
? file_name_length
: (filename_size - 1);
memcpy(reinterpret_cast<void*>(filename), p, len);
filename[len] = 0;
}
p += file_name_length;
p += extra_field_length;
p += file_comment_length;
return true;
}
// Gives a maximum bound on the size of the interface JAR. Basically, adds
// the difference between the compressed and uncompressed sizes to the size
// of the input file.
u8 InputZipFile::CalculateOutputLength() {
const u1* current = central_dir_;
u8 compressed_size = 0;
u8 uncompressed_size = 0;
u8 skipped_compressed_size = 0;
u4 attr;
u4 offset;
char filename[PATH_MAX];
while (true) {
size_t file_compressed, file_uncompressed;
if (!ProcessCentralDirEntry(current,
&file_compressed, &file_uncompressed,
filename, PATH_MAX, &attr, &offset)) {
break;
}
if (processor->Accept(filename, attr)) {
compressed_size += (u8) file_compressed;
uncompressed_size += (u8) file_uncompressed;
} else {
skipped_compressed_size += file_compressed;
}
}
// The worst case is when the output is simply the input uncompressed. The
// metadata in the zip file will stay the same, so the file will grow by the
// difference between the compressed and uncompressed sizes.
return (u8) in_length_ - skipped_compressed_size
+ (uncompressed_size - compressed_size);
}
// Given the data in the zip file, returns the offset of the central directory
// and the number of files contained in it.
bool FindZipCentralDirectory(const u1* bytes, size_t in_length,
u4* offset, const u1** central_dir) {
static const int MAX_COMMENT_LENGTH = 0xffff;
static const int CENTRAL_DIR_LOCATOR_SIZE = 22;
// Maximum distance of start of central dir locator from end of file
static const int MAX_DELTA = MAX_COMMENT_LENGTH + CENTRAL_DIR_LOCATOR_SIZE;
const u1* last_pos_to_check = in_length < MAX_DELTA
? bytes
: bytes + (in_length - MAX_DELTA);
const u1* current;
bool found = false;
for (current = bytes + in_length - CENTRAL_DIR_LOCATOR_SIZE;
current >= last_pos_to_check;
current-- ) {
const u1* p = current;
if (get_u4le(p) != END_OF_CENTRAL_DIR_SIGNATURE) {
continue;
}
p += 16; // skip to comment length field
u2 comment_length = get_u2le(p);
// Does the comment go exactly till the end of the file?
if (current + comment_length + CENTRAL_DIR_LOCATOR_SIZE
!= bytes + in_length) {
continue;
}
// Hooray, we found it!
found = true;
break;
}
if (!found) {
fprintf(stderr, "file is invalid or corrupted (missing end of central "
"directory record)\n");
return false;
}
const u1* end_of_central_dir = current;
get_u4le(current); // central directory locator signature, already checked
u2 number_of_this_disk = get_u2le(current);
u2 disk_with_central_dir = get_u2le(current);
u2 central_dir_entries_on_this_disk = get_u2le(current);
u2 central_dir_entries = get_u2le(current);
u4 central_dir_size = get_u4le(current);
u4 central_dir_offset = get_u4le(current);
u2 file_comment_length = get_u2le(current);
current += file_comment_length; // set current to the end of the central dir
if (number_of_this_disk != 0
|| disk_with_central_dir != 0
|| central_dir_entries_on_this_disk != central_dir_entries) {
fprintf(stderr, "multi-disk JAR files are not supported\n");
return false;
}
// Do not change output values before determining that they are OK.
*offset = central_dir_offset;
// Central directory start can then be used to determine the actual
// starts of the zip file (which can be different in case of a non-zip
// header like for auto-extractable binaries).
*central_dir = end_of_central_dir - central_dir_size;
return true;
}
void InputZipFile::Reset() {
central_dir_current_ = central_dir_;
zipdata_in_mapped_ = zipdata_in_;
p = zipdata_in_ + in_offset_;
}
int ZipExtractor::ProcessAll() {
while (ProcessNext()) {}
if (GetError() != NULL) {
return -1;
}
return 0;
}
ZipExtractor* ZipExtractor::Create(const char* filename,
ZipExtractorProcessor *processor) {
int fd_in = open(filename, O_RDONLY);
if (fd_in < 0) {
return NULL;
}
off_t length = lseek(fd_in, 0, SEEK_END);
if (length < 0) {
return NULL;
}
void *zipdata_in = mmap(NULL, length, PROT_READ, MAP_PRIVATE, fd_in, 0);
if (zipdata_in == MAP_FAILED) {
return NULL;
}
u4 central_dir_offset;
const u1 *central_dir = NULL;
if (!devtools_ijar::FindZipCentralDirectory(
static_cast<const u1*>(zipdata_in), length,
&central_dir_offset, &central_dir)) {
errno = EIO; // we don't really have a good error number
return NULL;
}
const u1 *zipdata_start = static_cast<const u1*>(zipdata_in);
off_t offset = - static_cast<off_t>(zipdata_start
+ central_dir_offset
- central_dir);
return new InputZipFile(processor, fd_in, length, offset,
zipdata_start, central_dir);
}
InputZipFile::InputZipFile(ZipExtractorProcessor *processor, int fd,
off_t in_length, off_t in_offset,
const u1* zipdata_in, const u1* central_dir)
: processor(processor), fd_in(fd),
zipdata_in_(zipdata_in), zipdata_in_mapped_(zipdata_in),
central_dir_(central_dir), in_length_(in_length), in_offset_(in_offset),
p(zipdata_in + in_offset), central_dir_current_(central_dir) {
uncompressed_data_allocated_ = INITIAL_BUFFER_SIZE;
uncompressed_data_ =
reinterpret_cast<u1*>(malloc(uncompressed_data_allocated_));
errmsg[0] = 0;
}
InputZipFile::~InputZipFile() {
free(uncompressed_data_);
close(fd_in);
}
//
// Implementation of OutputZipFile
//
int OutputZipFile::WriteEmptyFile(const char *filename) {
const u1* file_name = (const u1*) filename;
size_t file_name_length = strlen(filename);
LocalFileEntry *entry = new LocalFileEntry;
entry->local_header_offset = Offset(q);
entry->external_attr = 0;
entry->crc32 = 0;
// Output the ZIP local_file_header:
put_u4le(q, LOCAL_FILE_HEADER_SIGNATURE);
put_u2le(q, 10); // extract_version
put_u2le(q, 0); // general_purpose_bit_flag
put_u2le(q, 0); // compression_method
put_u2le(q, 0); // last_mod_file_time
put_u2le(q, 0); // last_mod_file_date
put_u4le(q, entry->crc32); // crc32
put_u4le(q, 0); // compressed_size
put_u4le(q, 0); // uncompressed_size
put_u2le(q, file_name_length);
put_u2le(q, 0); // extra_field_length
put_n(q, file_name, file_name_length);
entry->file_name_length = file_name_length;
entry->extra_field_length = 0;
entry->compressed_length = 0;
entry->uncompressed_length = 0;
entry->compression_method = 0;
entry->extra_field = (const u1 *)"";
entry->file_name = (u1*) strdup((const char *) file_name);
entries_.push_back(entry);
return 0;
}
void OutputZipFile::WriteCentralDirectory() {
// central directory:
const u1 *central_directory_start = q;
for (size_t ii = 0; ii < entries_.size(); ++ii) {
LocalFileEntry *entry = entries_[ii];
put_u4le(q, CENTRAL_FILE_HEADER_SIGNATURE);
put_u2le(q, 0); // version made by
put_u2le(q, ZIP_VERSION_TO_EXTRACT); // version to extract
put_u2le(q, 0); // general purpose bit flag
put_u2le(q, entry->compression_method); // compression method:
put_u2le(q, 0); // last_mod_file_time
put_u2le(q, 0); // last_mod_file_date
put_u4le(q, entry->crc32); // crc32
put_u4le(q, entry->compressed_length); // compressed_size
put_u4le(q, entry->uncompressed_length); // uncompressed_size
put_u2le(q, entry->file_name_length);
put_u2le(q, entry->extra_field_length);
put_u2le(q, 0); // file comment length
put_u2le(q, 0); // disk number start
put_u2le(q, 0); // internal file attributes
put_u4le(q, entry->external_attr); // external file attributes
// relative offset of local header:
put_u4le(q, entry->local_header_offset);
put_n(q, entry->file_name, entry->file_name_length);
put_n(q, entry->extra_field, entry->extra_field_length);
}
u4 central_directory_size = q - central_directory_start;
put_u4le(q, END_OF_CENTRAL_DIR_SIGNATURE);
put_u2le(q, 0); // number of this disk
put_u2le(q, 0); // number of the disk with the start of the central directory
put_u2le(q, entries_.size()); // # central dir entries on this disk
put_u2le(q, entries_.size()); // total # entries in the central directory
put_u4le(q, central_directory_size); // size of the central directory
put_u4le(q, Offset(central_directory_start)); // offset of start of central
// directory wrt starting disk
put_u2le(q, 0); // .ZIP file comment length
}
u1* OutputZipFile::WriteLocalFileHeader(const char* filename, const u4 attr) {
off_t file_name_length_ = strlen(filename);
LocalFileEntry *entry = new LocalFileEntry;
entry->local_header_offset = Offset(q);
entry->file_name_length = file_name_length_;
entry->file_name = new u1[file_name_length_];
entry->external_attr = attr;
memcpy(entry->file_name, filename, file_name_length_);
entry->extra_field_length = 0;
entry->extra_field = (const u1 *)"";
// Output the ZIP local_file_header:
put_u4le(q, LOCAL_FILE_HEADER_SIGNATURE);
put_u2le(q, ZIP_VERSION_TO_EXTRACT); // version to extract
put_u2le(q, 0); // general purpose bit flag
u1 *header_ptr = q;
put_u2le(q, COMPRESSION_METHOD_STORED); // compression method = placeholder
put_u2le(q, 0); // last_mod_file_time
put_u2le(q, 0); // last_mod_file_date
put_u4le(q, entry->crc32); // crc32
put_u4le(q, 0); // compressed_size = placeholder
put_u4le(q, 0); // uncompressed_size = placeholder
put_u2le(q, entry->file_name_length);
put_u2le(q, entry->extra_field_length);
put_n(q, entry->file_name, entry->file_name_length);
put_n(q, entry->extra_field, entry->extra_field_length);
entries_.push_back(entry);
return header_ptr;
}
// Try to compress a file entry in memory using the deflate algorithm.
// It will compress buf (of size length) unless the compressed size is bigger
// than the input size. The result will overwrite the content of buf and the
// final size is returned.
size_t TryDeflate(u1 *buf, size_t length) {
u1 *outbuf = reinterpret_cast<u1 *>(malloc(length));
z_stream stream;
// Initialize the z_stream strcut for reading from buf and wrinting in outbuf.
stream.zalloc = Z_NULL;
stream.zfree = Z_NULL;
stream.opaque = Z_NULL;
stream.total_in = length;
stream.avail_in = length;
stream.total_out = length;
stream.avail_out = length;
stream.next_in = buf;
stream.next_out = outbuf;
// deflateInit2 negative windows size prevent the zlib wrapper to be used.
if (deflateInit2(&stream, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
-MAX_WBITS, 8, Z_DEFAULT_STRATEGY) != Z_OK) {
// Failure to compress => return the buffer uncompressed
free(outbuf);
return length;
}
if (deflate(&stream, Z_FINISH) == Z_STREAM_END) {
// Compression successful and fits in outbuf, let's copy the result in buf.
length = stream.total_out;
memcpy(buf, outbuf, length);
}
deflateEnd(&stream);
free(outbuf);
// Return the length of the resulting buffer
return length;
}
size_t OutputZipFile::WriteFileSizeInLocalFileHeader(u1 *header_ptr,
size_t out_length,
bool compress,
const u4 crc) {
size_t compressed_size = out_length;
if (compress) {
compressed_size = TryDeflate(q, out_length);
}
// compression method
if (compressed_size < out_length) {
put_u2le(header_ptr, COMPRESSION_METHOD_DEFLATED);
} else {
put_u2le(header_ptr, COMPRESSION_METHOD_STORED);
}
header_ptr += 4;
put_u4le(header_ptr, crc); // crc32
put_u4le(header_ptr, compressed_size); // compressed_size
put_u4le(header_ptr, out_length); // uncompressed_size
return compressed_size;
}
int OutputZipFile::Finish() {
if (fd_out > 0) {
WriteCentralDirectory();
if (ftruncate(fd_out, GetSize()) < 0) {
return error("ftruncate(fd_out, GetSize()): %s", strerror(errno));
}
if (close(fd_out) < 0) {
return error("close(fd_out): %s", strerror(errno));
}
fd_out = -1;
}
return 0;
}
u1* OutputZipFile::NewFile(const char* filename, const u4 attr) {
header_ptr = WriteLocalFileHeader(filename, attr);
return q;
}
int OutputZipFile::FinishFile(size_t filelength, bool compress,
bool compute_crc) {
u4 crc = 0;
if (compute_crc) {
crc = crc32(crc, q, filelength);
}
size_t compressed_size =
WriteFileSizeInLocalFileHeader(header_ptr, filelength, compress, crc);
entries_.back()->crc32 = crc;
entries_.back()->compressed_length = compressed_size;
entries_.back()->uncompressed_length = filelength;
if (compressed_size < filelength) {
entries_.back()->compression_method = COMPRESSION_METHOD_DEFLATED;
} else {
entries_.back()->compression_method = COMPRESSION_METHOD_STORED;
}
q += compressed_size;
return 0;
}
ZipBuilder* ZipBuilder::Create(const char* zip_file, u8 estimated_size) {
if (estimated_size > kMaximumOutputSize) {
fprintf(stderr,
"Uncompressed input jar has size %llu, "
"which exceeds the maximum supported output size %llu.\n"
"Assuming that ijar will be smaller and hoping for the best.\n",
estimated_size, kMaximumOutputSize);
estimated_size = kMaximumOutputSize;
}
int fd_out = open(zip_file, O_CREAT|O_RDWR|O_TRUNC, 0644);
if (fd_out < 0) {
return NULL;
}
// Create mmap-able sparse file
if (ftruncate(fd_out, estimated_size) < 0) {
return NULL;
}
// Ensure that any buffer overflow in JarStripper will result in
// SIGSEGV or SIGBUS by over-allocating beyond the end of the file.
size_t mmap_length = std::min(estimated_size + sysconf(_SC_PAGESIZE),
(u8) std::numeric_limits<size_t>::max());
void *zipdata_out = mmap(NULL, mmap_length, PROT_WRITE,
MAP_SHARED, fd_out, 0);
if (zipdata_out == MAP_FAILED) {
fprintf(stderr, "output_length=%llu\n", estimated_size);
return NULL;
}
return new OutputZipFile(fd_out, (u1*) zipdata_out);
}
u8 ZipBuilder::EstimateSize(char **files) {
struct stat statst;
// Digital signature field size = 6, End of central directory = 22, Total = 28
u8 size = 28;
// Count the size of all the files in the input to estimate the size of the
// output.
for (int i = 0; files[i] != NULL; i++) {
if (stat(files[i], &statst) != 0) {
fprintf(stderr, "File %s does not seem to exist.", files[i]);
return 0;
}
size += statst.st_size;
// Add sizes of Zip meta data
// local file header = 30 bytes
// data descriptor = 12 bytes
// central directory descriptor = 46 bytes
// Total: 88bytes
size += 88;
// The filename is stored twice (once in the central directory
// and once in the local file header).
size += strlen(files[i]) * 2;
}
return size;
}
} // namespace devtools_ijar