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unzip: Remove some magic numbers and create directories when needed

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This commit also adds an assert about the compression method instead of
just writing out the compressed data.
This commit is contained in:
AnotherTest 2020-07-13 12:38:59 +04:30 • committed by Andreas Kling
parent 6a265f7c21
commit 3a7a689b87
1 changed files with 63 additions and 22 deletions
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53
Userland/unzip.cpp
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@ -64,29 +64,69 @@ bool find_next_central_directory(off_t file_size, const MappedFile& file, off_t
bool unpack_file_for_central_directory_index(off_t central_directory_index, const MappedFile& file)
{
enum CentralFileDirectoryHeaderOffsets {
CFDHCompressionMethodOffset = 10,
CFDHLocalFileHeaderIndexOffset = 42,
};
enum LocalFileHeaderOffsets {
LFHCompressionMethodOffset = 10,
LFHCompressedSizeOffset = 18,
LFHFileNameLengthOffset = 26,
LFHExtraFieldLengthOffset = 28,
LFHFileNameBaseOffset = 30,
};
enum CompressionMethod {
None = 0,
Shrunk = 1,
Factor1 = 2,
Factor2 = 3,
Factor3 = 4,
Factor4 = 5,
Implode = 6,
Deflate = 8,
EnhancedDeflate = 9,
PKWareDCLImplode = 10,
BZIP2 = 12,
LZMA = 14,
TERSE = 18,
LZ77 = 19,
};
u8 buffer[4];
if (!seek_and_read(buffer, file, central_directory_index + 42, 4))
if (!seek_and_read(buffer, file, central_directory_index + CFDHLocalFileHeaderIndexOffset, 4))
return false;
off_t local_file_header_index = buffer[3] << 24 | buffer[2] << 16 | buffer[1] << 8 | buffer[0];
if (!seek_and_read(buffer, file, local_file_header_index + 18, 4))
if (!seek_and_read(buffer, file, local_file_header_index + LFHCompressionMethodOffset, 2))
return false;
auto compression_method = buffer[1] << 8 | buffer[0];
// FIXME: Remove once any decompression is supported.
ASSERT(compression_method == None);
if (!seek_and_read(buffer, file, local_file_header_index + LFHCompressedSizeOffset, 4))
return false;
off_t compressed_file_size = buffer[3] << 24 | buffer[2] << 16 | buffer[1] << 8 | buffer[0];
if (!seek_and_read(buffer, file, local_file_header_index + 26, 2))
if (!seek_and_read(buffer, file, local_file_header_index + LFHFileNameLengthOffset, 2))
return false;
off_t file_name_length = buffer[1] << 8 | buffer[0];
if (!seek_and_read(buffer, file, local_file_header_index + 28, 2))
if (!seek_and_read(buffer, file, local_file_header_index + LFHExtraFieldLengthOffset, 2))
return false;
off_t extra_field_length = buffer[1] << 8 | buffer[0];
if (!seek_and_read(buffer, file, local_file_header_index + 30, file_name_length))
if (!seek_and_read(buffer, file, local_file_header_index + LFHFileNameBaseOffset, file_name_length))
return false;
char file_name[file_name_length + 1];
memcpy(file_name, buffer, file_name_length);
file_name[file_name_length] = '\0';
if (file_name[file_name_length - 1] == '/') {
if (mkdir(file_name, 0755) < 0) {
perror("mkdir");
return false;
}
} else {
auto new_file = Core::File::construct(String { file_name });
if (!new_file->open(Core::IODevice::WriteOnly)) {
fprintf(stderr, "Can't write file %s: %s\n", file_name, new_file->error_string());
@ -95,7 +135,7 @@ bool unpack_file_for_central_directory_index(off_t central_directory_index, cons
printf(" extracting: %s\n", file_name);
u8 raw_file_contents[compressed_file_size];
if (!seek_and_read(raw_file_contents, file, local_file_header_index + 30 + file_name_length + extra_field_length, compressed_file_size))
if (!seek_and_read(raw_file_contents, file, local_file_header_index + LFHFileNameBaseOffset + file_name_length + extra_field_length, compressed_file_size))
return false;
// FIXME: Try to uncompress data here. We're just ignoring it as no decompression methods are implemented yet.
@ -108,6 +148,7 @@ bool unpack_file_for_central_directory_index(off_t central_directory_index, cons
fprintf(stderr, "Can't close file %s: %s\n", file_name, new_file->error_string());
return false;
}
}
return true;
}