/* * Copyright (c) 2020, Peter Elliott * Copyright (c) 2021, Idan Horowitz * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #pragma once #include #include #include #include namespace Archive { enum class TarFileType : char { NormalFile = '0', AlternateNormalFile = '\0', HardLink = '1', SymLink = '2', CharacterSpecialFile = '3', BlockSpecialFile = '4', Directory = '5', FIFO = '6', ContiguousFile = '7', GlobalExtendedHeader = 'g', ExtendedHeader = 'x' }; constexpr size_t block_size = 512; constexpr const char* gnu_magic = "ustar "; // gnu format magic 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 [[gnu::packed]] TarFileHeader { public: 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); } gid_t gid() const { return get_tar_field(m_gid); } // FIXME: support 2001-star size encoding size_t size() const { return get_tar_field(m_size); } time_t timestamp() const { return get_tar_field(m_timestamp); } TarFileType type_flag() const { return TarFileType(m_type_flag); } const StringView link_name() const { return m_link_name; } const StringView magic() const { return StringView(m_magic, min(__builtin_strlen(m_magic), sizeof(m_magic))); } // in some cases this is a null terminated string, in others its not const StringView version() const { return StringView(m_version, min(__builtin_strlen(m_version), sizeof(m_version))); } // in some cases this is a null terminated string, in others its not const StringView owner_name() const { return m_owner_name; } 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(TarFileType type) { m_type_flag = static_cast(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]; char m_mode[8]; char m_uid[8]; char m_gid[8]; char m_size[12]; char m_timestamp[12]; 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]; char m_version[2]; char m_owner_name[32]; char m_group_name[32]; char m_major[8]; char m_minor[8]; char m_prefix[155]; // zero out the prefix for archiving template static size_t get_tar_field(const char (&field)[N]); }; template size_t TarFileHeader::get_tar_field(const char (&field)[N]) { size_t value = 0; for (size_t i = 0; i < N; ++i) { if (field[i] == 0) break; VERIFY(field[i] >= '0' && field[i] <= '7'); value *= 8; value += field[i] - '0'; } return value; } void TarFileHeader::calculate_checksum() { memset(m_checksum, ' ', sizeof(m_checksum)); auto checksum = 0u; for (auto i = 0u; i < sizeof(TarFileHeader); ++i) { checksum += ((unsigned char*)this)[i]; } VERIFY(String::formatted("{:o}", checksum).copy_characters_to_buffer(m_checksum, sizeof(m_checksum))); } }