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/*
* Copyright (c) 2020, Peter Elliott <pelliott@serenityos.org>
* Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
* Copyright (c) 2022, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Array.h>
#include <AK/OwnPtr.h>
#include <LibArchive/TarStream.h>
#include <string.h>
namespace Archive {
TarFileStream::TarFileStream(TarInputStream& tar_stream)
: m_tar_stream(tar_stream)
, m_generation(tar_stream.m_generation)
{
}
ErrorOr<Bytes> TarFileStream::read_some(Bytes bytes)
{
// Verify that the stream has not advanced.
VERIFY(m_tar_stream.m_generation == m_generation);
auto header_size = TRY(m_tar_stream.header().size());
auto to_read = min(bytes.size(), header_size - m_tar_stream.m_file_offset);
auto slice = TRY(m_tar_stream.m_stream->read_some(bytes.trim(to_read)));
m_tar_stream.m_file_offset += slice.size();
return slice;
}
bool TarFileStream::is_eof() const
{
// Verify that the stream has not advanced.
VERIFY(m_tar_stream.m_generation == m_generation);
auto header_size_or_error = m_tar_stream.header().size();
if (header_size_or_error.is_error())
return true;
auto header_size = header_size_or_error.release_value();
return m_tar_stream.m_stream->is_eof()
|| m_tar_stream.m_file_offset >= header_size;
}
ErrorOr<size_t> TarFileStream::write_some(ReadonlyBytes)
{
return Error::from_errno(EBADF);
}
ErrorOr<NonnullOwnPtr<TarInputStream>> TarInputStream::construct(NonnullOwnPtr<Stream> stream)
{
auto tar_stream = TRY(adopt_nonnull_own_or_enomem(new (nothrow) TarInputStream(move(stream))));
TRY(tar_stream->load_next_header());
return tar_stream;
}
TarInputStream::TarInputStream(NonnullOwnPtr<Stream> stream)
: m_stream(move(stream))
{
}
static constexpr unsigned long block_ceiling(unsigned long offset)
{
return block_size * (1 + ((offset - 1) / block_size));
}
ErrorOr<void> TarInputStream::advance()
{
if (finished())
return Error::from_string_literal("Attempted to advance a finished stream");
m_generation++;
// Discard the pending bytes of the current entry.
auto file_size = TRY(m_header.size());
TRY(m_stream->discard(block_ceiling(file_size) - m_file_offset));
m_file_offset = 0;
TRY(load_next_header());
return {};
}
ErrorOr<void> TarInputStream::load_next_header()
{
size_t number_of_consecutive_zero_blocks = 0;
while (true) {
m_header = TRY(m_stream->read_value<TarFileHeader>());
// Discard the rest of the header block.
TRY(m_stream->discard(block_size - sizeof(TarFileHeader)));
if (!header().is_zero_block())
break;
number_of_consecutive_zero_blocks++;
// Two zero blocks in a row marks the end of the archive.
if (number_of_consecutive_zero_blocks >= 2) {
m_found_end_of_archive = true;
return {};
}
}
if (!TRY(valid()))
return Error::from_string_literal("Header has an invalid magic or checksum");
return {};
}
ErrorOr<bool> TarInputStream::valid() const
{
auto const header_magic = header().magic();
auto const header_version = header().version();
if (!((header_magic == gnu_magic && header_version == gnu_version)
|| (header_magic == ustar_magic && header_version == ustar_version)
|| (header_magic == posix1_tar_magic && header_version == posix1_tar_version)))
return false;
// POSIX.1-1988 tar does not have magic numbers, so we also need to verify the header checksum.
return TRY(header().checksum()) == header().expected_checksum();
}
TarFileStream TarInputStream::file_contents()
{
VERIFY(!finished());
return TarFileStream(*this);
}
TarOutputStream::TarOutputStream(MaybeOwned<Stream> stream)
: m_stream(move(stream))
{
}
ErrorOr<void> TarOutputStream::add_directory(StringView path, mode_t mode)
{
VERIFY(!m_finished);
TarFileHeader header {};
TRY(header.set_size(0));
header.set_filename_and_prefix(TRY(String::formatted("{}/", path))); // Old tar implementations assume directory names end with a /
header.set_type_flag(TarFileType::Directory);
TRY(header.set_mode(mode));
header.set_magic(gnu_magic);
header.set_version(gnu_version);
TRY(header.calculate_checksum());
TRY(m_stream->write_until_depleted(Bytes { &header, sizeof(header) }));
u8 padding[block_size] = { 0 };
TRY(m_stream->write_until_depleted(Bytes { &padding, block_size - sizeof(header) }));
return {};
}
ErrorOr<void> TarOutputStream::add_file(StringView path, mode_t mode, ReadonlyBytes bytes)
{
VERIFY(!m_finished);
TarFileHeader header {};
TRY(header.set_size(bytes.size()));
header.set_filename_and_prefix(path);
header.set_type_flag(TarFileType::NormalFile);
TRY(header.set_mode(mode));
header.set_magic(gnu_magic);
header.set_version(gnu_version);
TRY(header.calculate_checksum());
TRY(m_stream->write_until_depleted(ReadonlyBytes { &header, sizeof(header) }));
constexpr Array<u8, block_size> padding { 0 };
TRY(m_stream->write_until_depleted(ReadonlyBytes { &padding, block_size - sizeof(header) }));
size_t n_written = 0;
while (n_written < bytes.size()) {
n_written += MUST(m_stream->write_some(bytes.slice(n_written, min(bytes.size() - n_written, block_size))));
}
TRY(m_stream->write_until_depleted(ReadonlyBytes { &padding, block_size - (n_written % block_size) }));
return {};
}
ErrorOr<void> TarOutputStream::add_link(StringView path, mode_t mode, StringView link_name)
{
VERIFY(!m_finished);
TarFileHeader header {};
TRY(header.set_size(0));
header.set_filename_and_prefix(path);
header.set_type_flag(TarFileType::SymLink);
TRY(header.set_mode(mode));
header.set_magic(gnu_magic);
header.set_version(gnu_version);
header.set_link_name(link_name);
TRY(header.calculate_checksum());
TRY(m_stream->write_until_depleted(Bytes { &header, sizeof(header) }));
u8 padding[block_size] = { 0 };
TRY(m_stream->write_until_depleted(Bytes { &padding, block_size - sizeof(header) }));
return {};
}
ErrorOr<void> TarOutputStream::finish()
{
VERIFY(!m_finished);
constexpr Array<u8, block_size> padding { 0 };
// 2 empty records that are used to signify the end of the archive.
TRY(m_stream->write_until_depleted(ReadonlyBytes { &padding, block_size }));
TRY(m_stream->write_until_depleted(ReadonlyBytes { &padding, block_size }));
m_finished = true;
return {};
}
}
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