beenull/ladybird
1
0
Fork 0
mirror of https://github.com/LadybirdBrowser/ladybird.git synced 2024-11-22 23:50:19 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 6

LibTar: Implement TarOutputStream

Browse source 
This output stream creates gnu format tar archives
and currently only supports files and directories.
This commit is contained in:
Idan Horowitz 2021-03-13 01:40:04 +02:00 committed by Andreas Kling
parent 6c1322bdc7
commit 7eab20bad0
Notes: sideshowbarker 2024-07-18 21:24:07 +09:00 
Author: https://github.com/IdanHo
Commit: https://github.com/SerenityOS/serenity/commit/7eab20bad01
Pull-request: https://github.com/SerenityOS/serenity/pull/5750
Issue: https://github.com/SerenityOS/serenity/issues/3989
Reviewed-by: https://github.com/alimpfard
Reviewed-by: https://github.com/bcoles
4 changed files with 116 additions and 16 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

38
Userland/Libraries/LibTar/Tar.h
View file

@ -27,7 +27,9 @@
#pragma once
#include <AK/String.h>
#include <AK/StringView.h>
#include <string.h>
#include <sys/types.h>
namespace Tar {
@ -52,9 +54,8 @@ constexpr const char* gnu_version = " "; // gnu format version
constexpr const char* ustar_magic = "ustar"; // ustar format magic
constexpr const char* ustar_version = "00"; // ustar format version
class Header {
class [[gnu::packed]] Header {
public:
// FIXME: support ustar filename prefix
const StringView file_name() const { return m_file_name; }
mode_t mode() const { return get_tar_field(m_mode); }
uid_t uid() const { return get_tar_field(m_uid); }
@ -70,6 +71,26 @@ public:
const StringView group_name() const { return m_group_name; }
int major() const { return get_tar_field(m_major); }
int minor() const { return get_tar_field(m_minor); }
// FIXME: support ustar filename prefix
const StringView prefix() const { return m_prefix; }
void set_file_name(const String& file_name) { VERIFY(file_name.copy_characters_to_buffer(m_file_name, sizeof(m_file_name))); }
void set_mode(mode_t mode) { VERIFY(String::formatted("{:o}", mode).copy_characters_to_buffer(m_mode, sizeof(m_mode))); }
void set_uid(uid_t uid) { VERIFY(String::formatted("{:o}", uid).copy_characters_to_buffer(m_uid, sizeof(m_uid))); }
void set_gid(gid_t gid) { VERIFY(String::formatted("{:o}", gid).copy_characters_to_buffer(m_gid, sizeof(m_gid))); }
void set_size(size_t size) { VERIFY(String::formatted("{:o}", size).copy_characters_to_buffer(m_size, sizeof(m_size))); }
void set_timestamp(time_t timestamp) { VERIFY(String::formatted("{:o}", timestamp).copy_characters_to_buffer(m_timestamp, sizeof(m_timestamp))); }
void set_type_flag(FileType type) { m_type_flag = type; }
void set_link_name(const String& link_name) { VERIFY(link_name.copy_characters_to_buffer(m_link_name, sizeof(m_link_name))); }
void set_magic(const char* magic) { memcpy(m_magic, magic, sizeof(m_magic)); } // magic doesnt necessarily include a null byte
void set_version(const char* version) { memcpy(m_version, version, sizeof(m_version)); } // version doesnt necessarily include a null byte
void set_owner_name(const String& owner_name) { VERIFY(owner_name.copy_characters_to_buffer(m_owner_name, sizeof(m_owner_name))); }
void set_group_name(const String& group_name) { VERIFY(group_name.copy_characters_to_buffer(m_group_name, sizeof(m_group_name))); }
void set_major(int major) { VERIFY(String::formatted("{:o}", major).copy_characters_to_buffer(m_major, sizeof(m_major))); }
void set_minor(int minor) { VERIFY(String::formatted("{:o}", minor).copy_characters_to_buffer(m_minor, sizeof(m_minor))); }
void set_prefix(const String& prefix) { VERIFY(prefix.copy_characters_to_buffer(m_prefix, sizeof(m_prefix))); }
void calculate_checksum();
private:
char m_file_name[100];
@ -78,7 +99,7 @@ private:
char m_gid[8];
char m_size[12];
char m_timestamp[12];
char m_checksum[8];
char m_checksum[8]; // an uninitialized header's checksum is filled with spaces
char m_type_flag;
char m_link_name[100];
char m_magic[6];
@ -87,7 +108,7 @@ private:
char m_group_name[32];
char m_major[8];
char m_minor[8];
char m_prefix[155];
char m_prefix[155]; // zero out the prefix for archiving
template<size_t N>
static size_t get_tar_field(const char (&field)[N]);
@ -107,5 +128,14 @@ size_t Header::get_tar_field(const char (&field)[N])
}
return value;
}
void Header::calculate_checksum()
{
memset(m_checksum, ' ', sizeof(m_checksum));
auto checksum = 0u;
for (auto i = 0u; i < sizeof(Header); ++i) {
checksum += ((unsigned char*)this)[i];
}
VERIFY(String::formatted("{:o}", checksum).copy_characters_to_buffer(m_checksum, sizeof(m_checksum)));
}
}

65
Userland/Libraries/LibTar/TarStream.cpp
View file

@ -26,9 +26,10 @@
*/
#include <LibTar/TarStream.h>
#include <string.h>
namespace Tar {
TarFileStream::TarFileStream(TarStream& tar_stream)
TarFileStream::TarFileStream(TarInputStream& tar_stream)
: m_tar_stream(tar_stream)
, m_generation(tar_stream.m_generation)
{
@ -83,11 +84,12 @@ bool TarFileStream::discard_or_error(size_t count)
return m_tar_stream.m_stream.discard_or_error(count);
}
TarStream::TarStream(InputStream& stream)
TarInputStream::TarInputStream(InputStream& stream)
: m_stream(stream)
{
if (!m_stream.read_or_error(Bytes(&m_header, sizeof(m_header)))) {
m_finished = true;
m_stream.handle_any_error(); // clear out errors so we dont assert
return;
}
VERIFY(m_stream.discard_or_error(block_size - sizeof(Header)));
@ -98,7 +100,7 @@ static constexpr unsigned long block_ceiling(unsigned long offset)
return block_size * (1 + ((offset - 1) / block_size));
}
void TarStream::advance()
void TarInputStream::advance()
{
if (m_finished)
return;
@ -119,17 +121,70 @@ void TarStream::advance()
VERIFY(m_stream.discard_or_error(block_size - sizeof(Header)));
}
bool TarStream::valid() const
bool TarInputStream::valid() const
{
auto& header_magic = header().magic();
auto& header_version = header().version();
return (header_magic == gnu_magic && header_version == gnu_version) || (header_magic == ustar_magic && header_version == ustar_version);
}
TarFileStream TarStream::file_contents()
TarFileStream TarInputStream::file_contents()
{
VERIFY(!m_finished);
return TarFileStream(*this);
}
TarOutputStream::TarOutputStream(OutputStream& stream)
: m_stream(stream)
{
}
void TarOutputStream::add_directory(const String& path, mode_t mode)
{
VERIFY(!m_finished);
Header header;
memset(&header, 0, sizeof(header));
header.set_size(0);
header.set_file_name(String::formatted("{}/", path)); // Old tar implementations assume directory names end with a /
header.set_type_flag(Directory);
header.set_mode(mode);
header.set_magic(gnu_magic);
header.set_version(gnu_version);
header.calculate_checksum();
VERIFY(m_stream.write_or_error(Bytes { &header, sizeof(header) }));
u8 padding[block_size] = { 0 };
VERIFY(m_stream.write_or_error(Bytes { &padding, block_size - sizeof(header) }));
}
void TarOutputStream::add_file(const String& path, mode_t mode, const ReadonlyBytes& bytes)
{
VERIFY(!m_finished);
Header header;
memset(&header, 0, sizeof(header));
header.set_size(bytes.size());
header.set_file_name(path);
header.set_type_flag(NormalFile);
header.set_mode(mode);
header.set_magic(gnu_magic);
header.set_version(gnu_version);
header.calculate_checksum();
VERIFY(m_stream.write_or_error(Bytes { &header, sizeof(header) }));
u8 padding[block_size] = { 0 };
VERIFY(m_stream.write_or_error(Bytes { &padding, block_size - sizeof(header) }));
size_t n_written = 0;
while (n_written < bytes.size()) {
n_written += m_stream.write(bytes.slice(n_written, min(bytes.size() - n_written, block_size)));
}
VERIFY(m_stream.write_or_error(Bytes { &padding, block_size - (n_written % block_size) }));
}
void TarOutputStream::finish()
{
VERIFY(!m_finished);
u8 padding[block_size] = { 0 };
m_stream.write_or_error(Bytes { &padding, block_size }); // 2 empty records that are used to signify the end of the archive
m_stream.write_or_error(Bytes { &padding, block_size });
m_finished = true;
}
}

27
Userland/Libraries/LibTar/TarStream.h
View file

@ -1,5 +1,6 @@
/*
* Copyright (c) 2020, Peter Elliott <pelliott@ualberta.ca>
* Copyright (c) 2021, Idan Horowitz <idan.horowitz@gmail.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@ -32,7 +33,7 @@
namespace Tar {
class TarStream;
class TarInputStream;
class TarFileStream : public InputStream {
public:
@ -43,16 +44,16 @@ public:
bool discard_or_error(size_t count) override;
private:
TarFileStream(TarStream& stream);
TarStream& m_tar_stream;
TarFileStream(TarInputStream& stream);
TarInputStream& m_tar_stream;
int m_generation;
friend class TarStream;
friend class TarInputStream;
};
class TarStream {
class TarInputStream {
public:
TarStream(InputStream&);
TarInputStream(InputStream&);
void advance();
bool finished() const { return m_finished; }
bool valid() const;
@ -69,4 +70,18 @@ private:
friend class TarFileStream;
};
class TarOutputStream {
public:
TarOutputStream(OutputStream&);
void add_file(const String& path, mode_t, const ReadonlyBytes&);
void add_directory(const String& path, mode_t);
void finish();
private:
OutputStream& m_stream;
bool m_finished { false };
friend class TarFileStream;
};
}

2
Userland/Utilities/tar.cpp
View file

@ -78,7 +78,7 @@ int main(int argc, char** argv)
InputStream& file_input_stream = file_stream;
InputStream& gzip_input_stream = gzip_stream;
Tar::TarStream tar_stream((gzip) ? gzip_input_stream : file_input_stream);
Tar::TarInputStream tar_stream((gzip) ? gzip_input_stream : file_input_stream);
if (!tar_stream.valid()) {
warnln("the provided file is not a well-formatted ustar file");
return 1;