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/*
* Copyright (c) 2021, sin-ack <sin-ack@protonmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include "ISO9660FileSystem.h"
#include <AK/CharacterTypes.h>
#include <AK/Endian.h>
#include <AK/HashFunctions.h>
#include <AK/NonnullRefPtr.h>
#include <AK/OwnPtr.h>
#include <AK/RefPtr.h>
#include <AK/StringHash.h>
#include <AK/StringView.h>
#include <Kernel/Debug.h>
#include <Kernel/FileSystem/BlockBasedFileSystem.h>
#include <Kernel/Forward.h>
#include <Kernel/KBuffer.h>
#include <Kernel/UnixTypes.h>
#include <Kernel/UserOrKernelBuffer.h>
namespace Kernel {
// NOTE: According to the spec, logical blocks 0 to 15 are system use.
constexpr u32 first_data_area_block = 16;
constexpr u32 logical_sector_size = 2048;
constexpr u32 max_cached_directory_entries = 128;
struct DirectoryState {
RefPtr<ISO9660FS::DirectoryEntry> entry;
u32 offset { 0 };
};
class ISO9660DirectoryIterator {
public:
ISO9660DirectoryIterator(ISO9660FS& fs, ISO::DirectoryRecordHeader const& header)
: m_fs(fs)
, m_current_header(&header)
{
// FIXME: Panic or alternative method?
(void)read_directory_contents();
get_header();
}
ISO::DirectoryRecordHeader const* operator*() { return m_current_header; }
// Recurses into subdirectories. May fail.
KResultOr<bool> next()
{
if (done())
return false;
dbgln_if(ISO9660_VERY_DEBUG, "next(): Called");
if (has_flag(m_current_header->file_flags, ISO::FileFlags::Directory)) {
dbgln_if(ISO9660_VERY_DEBUG, "next(): Recursing");
{
bool result = m_directory_stack.try_append(move(m_current_directory));
if (!result) {
return ENOMEM;
}
}
dbgln_if(ISO9660_VERY_DEBUG, "next(): Pushed into directory stack");
TRY(read_directory_contents());
dbgln_if(ISO9660_VERY_DEBUG, "next(): Read directory contents");
m_current_directory.offset = 0;
get_header();
if (m_current_header->length == 0) {
// We have found an empty directory, let's continue with the
// next one.
if (!go_up())
return false;
} else {
// We cannot skip here, as this is the first record in this
// extent.
return true;
}
}
return skip();
}
// Skips to the directory in the list, returns whether there was a next one.
// No allocation here, cannot fail.
bool skip()
{
VERIFY(m_current_directory.entry);
if (m_current_directory.offset >= m_current_directory.entry->length) {
dbgln_if(ISO9660_VERY_DEBUG, "skip(): Was at last item already");
return false;
}
m_current_directory.offset += m_current_header->length;
get_header();
if (m_current_header->length == 0) {
// According to ECMA 119, if a logical block contains directory
// records, then the leftover bytes in the logical block are
// all zeros. So if our directory header has a length of 0,
// we're probably looking at padding.
//
// Of course, this doesn't mean we're done; it only means that there
// are no more directory entries in *this* logical block. If we
// have at least one more logical block of data length to go, we
// need to snap to the next logical block, because directory records
// cannot span multiple logical blocks.
u32 remaining_bytes = m_current_directory.entry->length - m_current_directory.offset;
if (remaining_bytes > m_fs.logical_block_size()) {
m_current_directory.offset += remaining_bytes % m_fs.logical_block_size();
get_header();
dbgln_if(ISO9660_VERY_DEBUG, "skip(): Snapped to next logical block (succeeded)");
return true;
}
dbgln_if(ISO9660_VERY_DEBUG, "skip(): Was at the last logical block, at padding now (offset {}, data length {})", m_current_directory.entry->length, m_current_directory.offset);
return false;
}
dbgln_if(ISO9660_VERY_DEBUG, "skip(): Skipped to next item");
return true;
}
bool go_up()
{
if (m_directory_stack.is_empty()) {
dbgln_if(ISO9660_VERY_DEBUG, "go_up(): Empty directory stack");
return false;
}
m_current_directory = m_directory_stack.take_last();
get_header();
dbgln_if(ISO9660_VERY_DEBUG, "go_up(): Went up a directory");
return true;
}
bool done() const
{
VERIFY(m_current_directory.entry);
auto result = m_directory_stack.is_empty() && m_current_directory.offset >= m_current_directory.entry->length;
dbgln_if(ISO9660_VERY_DEBUG, "done(): {}", result);
return result;
}
private:
KResult read_directory_contents()
{
m_current_directory.entry = TRY(m_fs.directory_entry_for_record({}, m_current_header));
return KSuccess;
}
void get_header()
{
VERIFY(m_current_directory.entry);
if (!m_current_directory.entry->blocks)
return;
m_current_header = reinterpret_cast<ISO::DirectoryRecordHeader const*>(m_current_directory.entry->blocks->data() + m_current_directory.offset);
}
ISO9660FS& m_fs;
DirectoryState m_current_directory;
ISO::DirectoryRecordHeader const* m_current_header { nullptr };
Vector<DirectoryState> m_directory_stack;
};
KResultOr<NonnullRefPtr<ISO9660FS>> ISO9660FS::try_create(OpenFileDescription& description)
{
return adopt_nonnull_ref_or_enomem(new (nothrow) ISO9660FS(description));
}
ISO9660FS::ISO9660FS(OpenFileDescription& description)
: BlockBasedFileSystem(description)
{
set_block_size(logical_sector_size);
m_logical_block_size = logical_sector_size;
}
ISO9660FS::~ISO9660FS()
{
}
KResult ISO9660FS::initialize()
{
TRY(BlockBasedFileSystem::initialize());
TRY(parse_volume_set());
TRY(create_root_inode());
return KSuccess;
}
Inode& ISO9660FS::root_inode()
{
VERIFY(!m_root_inode.is_null());
return *m_root_inode;
}
unsigned ISO9660FS::total_block_count() const
{
return LittleEndian { m_primary_volume->volume_space_size.little };
}
unsigned ISO9660FS::total_inode_count() const
{
if (!m_cached_inode_count) {
auto result = calculate_inode_count();
if (result.is_error()) {
// FIXME: This should be able to return a KResult.
return 0;
}
}
return m_cached_inode_count;
}
u8 ISO9660FS::internal_file_type_to_directory_entry_type(const DirectoryEntryView& entry) const
{
if (has_flag(static_cast<ISO::FileFlags>(entry.file_type), ISO::FileFlags::Directory)) {
return DT_DIR;
}
return DT_REG;
}
KResult ISO9660FS::parse_volume_set()
{
VERIFY(!m_primary_volume);
auto block = TRY(KBuffer::try_create_with_size(m_logical_block_size, Memory::Region::Access::Read | Memory::Region::Access::Write, "ISO9660FS: Temporary volume descriptor storage"));
auto block_buffer = UserOrKernelBuffer::for_kernel_buffer(block->data());
auto current_block_index = first_data_area_block;
while (true) {
bool result = raw_read(BlockIndex { current_block_index }, block_buffer);
if (!result) {
dbgln_if(ISO9660_DEBUG, "Failed to read volume descriptor from ISO file");
return EIO;
}
auto header = reinterpret_cast<ISO::VolumeDescriptorHeader const*>(block->data());
if (StringView { header->identifier, 5 } != "CD001") {
dbgln_if(ISO9660_DEBUG, "Header magic at volume descriptor {} is not valid", current_block_index - first_data_area_block);
return EIO;
}
switch (header->type) {
case ISO::VolumeDescriptorType::PrimaryVolumeDescriptor: {
auto primary_volume = reinterpret_cast<ISO::PrimaryVolumeDescriptor const*>(header);
m_primary_volume = adopt_own_if_nonnull(new ISO::PrimaryVolumeDescriptor(*primary_volume));
break;
}
case ISO::VolumeDescriptorType::BootRecord:
case ISO::VolumeDescriptorType::SupplementaryOrEnhancedVolumeDescriptor:
case ISO::VolumeDescriptorType::VolumePartitionDescriptor: {
break;
}
case ISO::VolumeDescriptorType::VolumeDescriptorSetTerminator: {
goto all_headers_read;
}
default:
dbgln_if(ISO9660_DEBUG, "Unexpected volume descriptor type {} in volume set", static_cast<u8>(header->type));
return EIO;
}
current_block_index++;
}
all_headers_read:
if (!m_primary_volume) {
dbgln_if(ISO9660_DEBUG, "Could not find primary volume");
return EIO;
}
m_logical_block_size = LittleEndian { m_primary_volume->logical_block_size.little };
return KSuccess;
}
KResult ISO9660FS::create_root_inode()
{
if (!m_primary_volume) {
dbgln_if(ISO9660_DEBUG, "Primary volume doesn't exist, can't create root inode");
return EIO;
}
m_root_inode = TRY(ISO9660Inode::try_create_from_directory_record(*this, m_primary_volume->root_directory_record_header, {}));
return KSuccess;
}
KResult ISO9660FS::calculate_inode_count() const
{
if (!m_primary_volume) {
dbgln_if(ISO9660_DEBUG, "Primary volume doesn't exist, can't calculate inode count");
return EIO;
}
size_t inode_count = 1;
TRY(visit_directory_record(m_primary_volume->root_directory_record_header, [&](ISO::DirectoryRecordHeader const* header) {
if (header == nullptr) {
return RecursionDecision::Continue;
}
inode_count += 1;
if (has_flag(header->file_flags, ISO::FileFlags::Directory)) {
if (header->file_identifier_length == 1) {
auto file_identifier = reinterpret_cast<u8 const*>(header + 1);
if (file_identifier[0] == '\0' || file_identifier[0] == '\1') {
return RecursionDecision::Continue;
}
}
return RecursionDecision::Recurse;
}
return RecursionDecision::Continue;
}));
m_cached_inode_count = inode_count;
return KSuccess;
}
KResult ISO9660FS::visit_directory_record(ISO::DirectoryRecordHeader const& record, Function<KResultOr<RecursionDecision>(ISO::DirectoryRecordHeader const*)> const& visitor) const
{
if (!has_flag(record.file_flags, ISO::FileFlags::Directory)) {
return KSuccess;
}
ISO9660DirectoryIterator iterator { const_cast<ISO9660FS&>(*this), record };
while (!iterator.done()) {
auto decision = TRY(visitor(*iterator));
switch (decision) {
case RecursionDecision::Recurse: {
auto has_moved = TRY(iterator.next());
if (!has_moved) {
// If next() hasn't moved then we have read through all the
// directories, and can exit.
return KSuccess;
}
continue;
}
case RecursionDecision::Continue: {
while (!iterator.done()) {
if (iterator.skip())
break;
if (!iterator.go_up())
return KSuccess;
}
continue;
}
case RecursionDecision::Break:
return KSuccess;
}
}
return KSuccess;
}
KResultOr<NonnullRefPtr<ISO9660FS::DirectoryEntry>> ISO9660FS::directory_entry_for_record(Badge<ISO9660DirectoryIterator>, ISO::DirectoryRecordHeader const* record)
{
u32 extent_location = LittleEndian { record->extent_location.little };
u32 data_length = LittleEndian { record->data_length.little };
auto key = calculate_directory_entry_cache_key(*record);
auto it = m_directory_entry_cache.find(key);
if (it != m_directory_entry_cache.end()) {
dbgln_if(ISO9660_DEBUG, "Cache hit for dirent @ {}", extent_location);
return it->value;
}
dbgln_if(ISO9660_DEBUG, "Cache miss for dirent @ {} :^(", extent_location);
if (m_directory_entry_cache.size() == max_cached_directory_entries) {
// FIXME: A smarter algorithm would probably be nicer.
m_directory_entry_cache.remove(m_directory_entry_cache.begin());
}
if (!(data_length % logical_block_size() == 0)) {
dbgln_if(ISO9660_DEBUG, "Found a directory with non-logical block size aligned data length!");
return EIO;
}
auto blocks = TRY(KBuffer::try_create_with_size(data_length, Memory::Region::Access::Read | Memory::Region::Access::Write, "ISO9660FS: Directory traversal buffer"));
auto blocks_buffer = UserOrKernelBuffer::for_kernel_buffer(blocks->data());
auto did_read = raw_read_blocks(BlockBasedFileSystem::BlockIndex { extent_location }, data_length / logical_block_size(), blocks_buffer);
if (!did_read) {
return EIO;
}
auto entry = TRY(DirectoryEntry::try_create(extent_location, data_length, move(blocks)));
m_directory_entry_cache.set(key, entry);
dbgln_if(ISO9660_DEBUG, "Cached dirent @ {}", extent_location);
return entry;
}
u32 ISO9660FS::calculate_directory_entry_cache_key(ISO::DirectoryRecordHeader const& record)
{
return LittleEndian { record.extent_location.little };
}
KResultOr<size_t> ISO9660Inode::read_bytes(off_t offset, size_t size, UserOrKernelBuffer& buffer, OpenFileDescription*) const
{
MutexLocker inode_locker(m_inode_lock);
u32 data_length = LittleEndian { m_record.data_length.little };
u32 extent_location = LittleEndian { m_record.extent_location.little };
if (static_cast<u64>(offset) >= data_length)
return 0;
auto block = TRY(KBuffer::try_create_with_size(fs().m_logical_block_size));
auto block_buffer = UserOrKernelBuffer::for_kernel_buffer(block->data());
size_t total_bytes = min(size, data_length - offset);
size_t nread = 0;
size_t blocks_already_read = offset / fs().m_logical_block_size;
size_t initial_offset = offset % fs().m_logical_block_size;
auto current_block_index = BlockBasedFileSystem::BlockIndex { extent_location + blocks_already_read };
while (nread != total_bytes) {
size_t bytes_to_read = min(total_bytes - nread, fs().logical_block_size() - initial_offset);
auto buffer_offset = buffer.offset(nread);
dbgln_if(ISO9660_VERY_DEBUG, "ISO9660Inode::read_bytes: Reading {} bytes into buffer offset {}/{}, logical block index: {}", bytes_to_read, nread, total_bytes, current_block_index.value());
if (bool result = const_cast<ISO9660FS&>(fs()).raw_read(current_block_index, block_buffer); !result) {
return EIO;
}
TRY(buffer_offset.write(block->data() + initial_offset, bytes_to_read));
nread += bytes_to_read;
initial_offset = 0;
current_block_index = BlockBasedFileSystem::BlockIndex { current_block_index.value() + 1 };
}
return nread;
}
InodeMetadata ISO9660Inode::metadata() const
{
return m_metadata;
}
KResult ISO9660Inode::traverse_as_directory(Function<bool(FileSystem::DirectoryEntryView const&)> visitor) const
{
Array<u8, max_file_identifier_length> file_identifier_buffer;
return fs().visit_directory_record(m_record, [&](ISO::DirectoryRecordHeader const* record) {
StringView filename = get_normalized_filename(*record, file_identifier_buffer);
dbgln_if(ISO9660_VERY_DEBUG, "traverse_as_directory(): Found {}", filename);
InodeIdentifier id { fsid(), get_inode_index(*record, filename) };
auto entry = FileSystem::DirectoryEntryView(filename, id, static_cast<u8>(record->file_flags));
if (!visitor(entry)) {
return RecursionDecision::Break;
}
return RecursionDecision::Continue;
});
}
KResultOr<NonnullRefPtr<Inode>> ISO9660Inode::lookup(StringView name)
{
RefPtr<Inode> inode;
Array<u8, max_file_identifier_length> file_identifier_buffer;
TRY(fs().visit_directory_record(m_record, [&](ISO::DirectoryRecordHeader const* record) {
StringView filename = get_normalized_filename(*record, file_identifier_buffer);
if (filename == name) {
auto maybe_inode = ISO9660Inode::try_create_from_directory_record(fs(), *record, filename);
if (maybe_inode.is_error()) {
// FIXME: The Inode API does not handle allocation failures very
// well... we can't return a KResultOr from here. It
// would be nice if we could return a KResult(Or) from
// any place where allocation may happen.
dbgln("Could not allocate inode for lookup!");
} else {
inode = maybe_inode.release_value();
}
return RecursionDecision::Break;
}
return RecursionDecision::Continue;
}));
if (!inode)
return ENOENT;
return inode.release_nonnull();
}
KResult ISO9660Inode::flush_metadata()
{
return KSuccess;
}
KResultOr<size_t> ISO9660Inode::write_bytes(off_t, size_t, const UserOrKernelBuffer&, OpenFileDescription*)
{
return EROFS;
}
KResultOr<NonnullRefPtr<Inode>> ISO9660Inode::create_child(StringView, mode_t, dev_t, UserID, GroupID)
{
return EROFS;
}
KResult ISO9660Inode::add_child(Inode&, const StringView&, mode_t)
{
return EROFS;
}
KResult ISO9660Inode::remove_child(const StringView&)
{
return EROFS;
}
KResult ISO9660Inode::chmod(mode_t)
{
return EROFS;
}
KResult ISO9660Inode::chown(UserID, GroupID)
{
return EROFS;
}
KResult ISO9660Inode::truncate(u64)
{
return EROFS;
}
KResult ISO9660Inode::set_atime(time_t)
{
return EROFS;
}
KResult ISO9660Inode::set_ctime(time_t)
{
return EROFS;
}
KResult ISO9660Inode::set_mtime(time_t)
{
return EROFS;
}
void ISO9660Inode::one_ref_left()
{
}
ISO9660Inode::ISO9660Inode(ISO9660FS& fs, ISO::DirectoryRecordHeader const& record, StringView const& name)
: Inode(fs, get_inode_index(record, name))
, m_record(record)
{
dbgln_if(ISO9660_VERY_DEBUG, "Creating inode #{}", index());
create_metadata();
}
ISO9660Inode::~ISO9660Inode()
{
}
KResultOr<NonnullRefPtr<ISO9660Inode>> ISO9660Inode::try_create_from_directory_record(ISO9660FS& fs, ISO::DirectoryRecordHeader const& record, StringView const& name)
{
return adopt_nonnull_ref_or_enomem(new (nothrow) ISO9660Inode(fs, record, name));
}
void ISO9660Inode::create_metadata()
{
u32 data_length = LittleEndian { m_record.data_length.little };
bool is_directory = has_flag(m_record.file_flags, ISO::FileFlags::Directory);
time_t recorded_at = parse_numerical_date_time(m_record.recording_date_and_time);
m_metadata = {
.inode = identifier(),
.size = data_length,
.mode = static_cast<mode_t>((is_directory ? S_IFDIR : S_IFREG) | (is_directory ? 0555 : 0444)),
.uid = 0,
.gid = 0,
.link_count = 1,
.atime = recorded_at,
.ctime = recorded_at,
.mtime = recorded_at,
.dtime = 0,
.block_count = 0,
.block_size = 0,
.major_device = 0,
.minor_device = 0,
};
}
time_t ISO9660Inode::parse_numerical_date_time(ISO::NumericalDateAndTime const& date)
{
i32 year_offset = date.years_since_1900 - 70;
return (year_offset * 60 * 60 * 24 * 30 * 12)
+ (date.month * 60 * 60 * 24 * 30)
+ (date.day * 60 * 60 * 24)
+ (date.hour * 60 * 60)
+ (date.minute * 60)
+ date.second;
}
StringView ISO9660Inode::get_normalized_filename(ISO::DirectoryRecordHeader const& record, Bytes buffer)
{
auto file_identifier = reinterpret_cast<u8 const*>(&record + 1);
auto filename = StringView { file_identifier, record.file_identifier_length };
if (filename.length() == 1) {
if (filename[0] == '\0') {
filename = "."sv;
}
if (filename[0] == '\1') {
filename = ".."sv;
}
}
if (!has_flag(record.file_flags, ISO::FileFlags::Directory)) {
// FIXME: We currently strip the file version from the filename,
// but that may be used later down the line if the file actually
// has multiple versions on the disk.
Optional<size_t> semicolon = filename.find(';');
if (semicolon.has_value()) {
filename = filename.substring_view(0, semicolon.value());
}
if (filename[filename.length() - 1] == '.') {
filename = filename.substring_view(0, filename.length() - 1);
}
}
if (filename.length() > buffer.size()) {
// FIXME: Rock Ridge allows filenames up to 255 characters, so we should
// probably support that instead of truncating.
filename = filename.substring_view(0, buffer.size());
}
for (size_t i = 0; i < filename.length(); i++) {
buffer[i] = to_ascii_lowercase(filename[i]);
}
return { buffer.data(), filename.length() };
}
InodeIndex ISO9660Inode::get_inode_index(ISO::DirectoryRecordHeader const& record, StringView const& name)
{
if (name.is_null()) {
// NOTE: This is the index of the root inode.
return 1;
}
return { pair_int_hash(LittleEndian { record.extent_location.little }, string_hash(name.characters_without_null_termination(), name.length())) };
}
}
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