ladybird/Services/RequestServer/Cache/CacheEntry.cpp
Timothy Flynn 0020af37cd RequestServer: Do not pack the disk cache header and footer structures
This is causing misaligned reads with Address Sanitizer enabled. We
could maintain the packed attribute, and deal with alignment - but we
ended up not actually needing these to be packed anyways. The only thing
we need to know is the serialized size of the header, which we can just
determine differently.
2025-11-20 09:33:49 +01:00

358 lines
12 KiB
C++

/*
* Copyright (c) 2025, Tim Flynn <trflynn89@ladybird.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/ScopeGuard.h>
#include <LibCore/Notifier.h>
#include <LibCore/System.h>
#include <LibFileSystem/FileSystem.h>
#include <RequestServer/Cache/CacheEntry.h>
#include <RequestServer/Cache/CacheIndex.h>
#include <RequestServer/Cache/DiskCache.h>
#include <RequestServer/Cache/Utilities.h>
namespace RequestServer {
ErrorOr<CacheHeader> CacheHeader::read_from_stream(Stream& stream)
{
CacheHeader header;
header.magic = TRY(stream.read_value<u32>());
header.version = TRY(stream.read_value<u32>());
header.url_size = TRY(stream.read_value<u32>());
header.url_hash = TRY(stream.read_value<u32>());
header.status_code = TRY(stream.read_value<u32>());
header.reason_phrase_size = TRY(stream.read_value<u32>());
header.reason_phrase_hash = TRY(stream.read_value<u32>());
return header;
}
ErrorOr<void> CacheHeader::write_to_stream(Stream& stream) const
{
TRY(stream.write_value(magic));
TRY(stream.write_value(version));
TRY(stream.write_value(url_size));
TRY(stream.write_value(url_hash));
TRY(stream.write_value(status_code));
TRY(stream.write_value(reason_phrase_size));
TRY(stream.write_value(reason_phrase_hash));
return {};
}
ErrorOr<void> CacheFooter::write_to_stream(Stream& stream) const
{
TRY(stream.write_value(data_size));
TRY(stream.write_value(crc32));
return {};
}
ErrorOr<CacheFooter> CacheFooter::read_from_stream(Stream& stream)
{
CacheFooter footer;
footer.data_size = TRY(stream.read_value<u64>());
footer.crc32 = TRY(stream.read_value<u32>());
return footer;
}
CacheEntry::CacheEntry(DiskCache& disk_cache, CacheIndex& index, u64 cache_key, String url, LexicalPath path, CacheHeader cache_header)
: m_disk_cache(disk_cache)
, m_index(index)
, m_cache_key(cache_key)
, m_url(move(url))
, m_path(move(path))
, m_cache_header(cache_header)
{
}
void CacheEntry::remove()
{
(void)FileSystem::remove(m_path.string(), FileSystem::RecursionMode::Disallowed);
m_index.remove_entry(m_cache_key);
}
void CacheEntry::close_and_destroy_cache_entry()
{
m_disk_cache.cache_entry_closed({}, *this);
}
ErrorOr<NonnullOwnPtr<CacheEntryWriter>> CacheEntryWriter::create(DiskCache& disk_cache, CacheIndex& index, u64 cache_key, String url, UnixDateTime request_time)
{
auto path = path_for_cache_key(disk_cache.cache_directory(), cache_key);
auto unbuffered_file = TRY(Core::File::open(path.string(), Core::File::OpenMode::Write));
auto file = TRY(Core::OutputBufferedFile::create(move(unbuffered_file)));
CacheHeader cache_header;
cache_header.url_size = url.byte_count();
cache_header.url_hash = url.hash();
return adopt_own(*new CacheEntryWriter { disk_cache, index, cache_key, move(url), move(path), move(file), cache_header, request_time });
}
CacheEntryWriter::CacheEntryWriter(DiskCache& disk_cache, CacheIndex& index, u64 cache_key, String url, LexicalPath path, NonnullOwnPtr<Core::OutputBufferedFile> file, CacheHeader cache_header, UnixDateTime request_time)
: CacheEntry(disk_cache, index, cache_key, move(url), move(path), cache_header)
, m_file(move(file))
, m_request_time(request_time)
, m_response_time(UnixDateTime::now())
{
}
ErrorOr<void> CacheEntryWriter::write_status_and_reason(u32 status_code, Optional<String> reason_phrase, HTTP::HeaderMap const& response_headers)
{
if (m_marked_for_deletion) {
close_and_destroy_cache_entry();
return Error::from_string_literal("Cache entry has been deleted");
}
m_cache_header.status_code = status_code;
if (reason_phrase.has_value()) {
m_cache_header.reason_phrase_size = reason_phrase->byte_count();
m_cache_header.reason_phrase_hash = reason_phrase->hash();
}
auto result = [&]() -> ErrorOr<void> {
if (!is_cacheable(status_code, response_headers))
return Error::from_string_literal("Response is not cacheable");
auto freshness_lifetime = calculate_freshness_lifetime(status_code, response_headers);
auto current_age = calculate_age(response_headers, m_request_time, m_response_time);
// We can cache already-expired responses if there are other cache directives that allow us to revalidate the
// response on subsequent requests. For example, `Cache-Control: max-age=0, must-revalidate`.
if (cache_lifetime_status(response_headers, freshness_lifetime, current_age) == CacheLifetimeStatus::Expired)
return Error::from_string_literal("Response has already expired");
TRY(m_file->write_value(m_cache_header));
TRY(m_file->write_until_depleted(m_url));
if (reason_phrase.has_value())
TRY(m_file->write_until_depleted(*reason_phrase));
return {};
}();
if (result.is_error()) {
dbgln("\033[31;1mUnable to write status/reason to cache entry for\033[0m {}: {}", m_url, result.error());
remove();
close_and_destroy_cache_entry();
return result.release_error();
}
return {};
}
ErrorOr<void> CacheEntryWriter::write_data(ReadonlyBytes data)
{
if (m_marked_for_deletion) {
close_and_destroy_cache_entry();
return Error::from_string_literal("Cache entry has been deleted");
}
if (auto result = m_file->write_until_depleted(data); result.is_error()) {
dbgln("\033[31;1mUnable to write data to cache entry for\033[0m {}: {}", m_url, result.error());
remove();
close_and_destroy_cache_entry();
return result.release_error();
}
m_cache_footer.data_size += data.size();
// FIXME: Update the crc.
return {};
}
ErrorOr<void> CacheEntryWriter::flush(HTTP::HeaderMap response_headers)
{
ScopeGuard guard { [&]() { close_and_destroy_cache_entry(); } };
if (m_marked_for_deletion)
return Error::from_string_literal("Cache entry has been deleted");
if (auto result = m_file->write_value(m_cache_footer); result.is_error()) {
dbgln("\033[31;1mUnable to flush cache entry for\033[0m {}: {}", m_url, result.error());
remove();
return result.release_error();
}
m_index.create_entry(m_cache_key, m_url, move(response_headers), m_cache_footer.data_size, m_request_time, m_response_time);
dbgln("\033[34;1mFinished caching\033[0m {} ({} bytes)", m_url, m_cache_footer.data_size);
return {};
}
ErrorOr<NonnullOwnPtr<CacheEntryReader>> CacheEntryReader::create(DiskCache& disk_cache, CacheIndex& index, u64 cache_key, HTTP::HeaderMap response_headers, u64 data_size)
{
auto path = path_for_cache_key(disk_cache.cache_directory(), cache_key);
auto file = TRY(Core::File::open(path.string(), Core::File::OpenMode::Read));
auto fd = file->fd();
CacheHeader cache_header;
size_t cache_header_size { 0 };
String url;
Optional<String> reason_phrase;
auto result = [&]() -> ErrorOr<void> {
cache_header = TRY(file->read_value<CacheHeader>());
cache_header_size = TRY(file->tell());
if (cache_header.magic != CacheHeader::CACHE_MAGIC)
return Error::from_string_literal("Magic value mismatch");
if (cache_header.version != CACHE_VERSION)
return Error::from_string_literal("Version mismatch");
url = TRY(String::from_stream(*file, cache_header.url_size));
if (url.hash() != cache_header.url_hash)
return Error::from_string_literal("URL hash mismatch");
if (cache_header.reason_phrase_size != 0) {
reason_phrase = TRY(String::from_stream(*file, cache_header.reason_phrase_size));
if (reason_phrase->hash() != cache_header.reason_phrase_hash)
return Error::from_string_literal("Reason phrase hash mismatch");
}
return {};
}();
if (result.is_error()) {
(void)FileSystem::remove(path.string(), FileSystem::RecursionMode::Disallowed);
return result.release_error();
}
auto data_offset = cache_header_size + cache_header.url_size + cache_header.reason_phrase_size;
return adopt_own(*new CacheEntryReader { disk_cache, index, cache_key, move(url), move(path), move(file), fd, cache_header, move(reason_phrase), move(response_headers), data_offset, data_size });
}
CacheEntryReader::CacheEntryReader(DiskCache& disk_cache, CacheIndex& index, u64 cache_key, String url, LexicalPath path, NonnullOwnPtr<Core::File> file, int fd, CacheHeader cache_header, Optional<String> reason_phrase, HTTP::HeaderMap response_headers, u64 data_offset, u64 data_size)
: CacheEntry(disk_cache, index, cache_key, move(url), move(path), cache_header)
, m_file(move(file))
, m_fd(fd)
, m_reason_phrase(move(reason_phrase))
, m_response_headers(move(response_headers))
, m_data_offset(data_offset)
, m_data_size(data_size)
{
}
void CacheEntryReader::revalidation_succeeded(HTTP::HeaderMap const& response_headers)
{
dbgln("\033[34;1mCache revalidation succeeded for\033[0m {}", m_url);
update_header_fields(m_response_headers, response_headers);
m_index.update_response_headers(m_cache_key, m_response_headers);
}
void CacheEntryReader::revalidation_failed()
{
dbgln("\033[33;1mCache revalidation failed for\033[0m {}", m_url);
remove();
close_and_destroy_cache_entry();
}
void CacheEntryReader::pipe_to(int pipe_fd, Function<void(u64)> on_complete, Function<void(u64)> on_error)
{
VERIFY(m_pipe_fd == -1);
m_pipe_fd = pipe_fd;
m_on_pipe_complete = move(on_complete);
m_on_pipe_error = move(on_error);
if (m_marked_for_deletion) {
pipe_error(Error::from_string_literal("Cache entry has been deleted"));
return;
}
m_pipe_write_notifier = Core::Notifier::construct(m_pipe_fd, Core::NotificationType::Write);
m_pipe_write_notifier->set_enabled(false);
m_pipe_write_notifier->on_activation = [this]() {
m_pipe_write_notifier->set_enabled(false);
pipe_without_blocking();
};
pipe_without_blocking();
}
void CacheEntryReader::pipe_without_blocking()
{
if (m_marked_for_deletion) {
pipe_error(Error::from_string_literal("Cache entry has been deleted"));
return;
}
auto result = Core::System::transfer_file_through_pipe(m_fd, m_pipe_fd, m_data_offset + m_bytes_piped, m_data_size - m_bytes_piped);
if (result.is_error()) {
if (result.error().code() != EAGAIN && result.error().code() != EWOULDBLOCK)
pipe_error(result.release_error());
else
m_pipe_write_notifier->set_enabled(true);
return;
}
m_bytes_piped += result.value();
if (m_bytes_piped == m_data_size) {
pipe_complete();
return;
}
pipe_without_blocking();
}
void CacheEntryReader::pipe_complete()
{
if (auto result = read_and_validate_footer(); result.is_error()) {
dbgln("\033[31;1mError validating cache entry for\033[0m {}: {}", m_url, result.error());
remove();
if (m_on_pipe_error)
m_on_pipe_error(m_bytes_piped);
} else {
m_index.update_last_access_time(m_cache_key);
if (m_on_pipe_complete)
m_on_pipe_complete(m_bytes_piped);
}
close_and_destroy_cache_entry();
}
void CacheEntryReader::pipe_error(Error error)
{
dbgln("\033[31;1mError transferring cache to pipe for\033[0m {}: {}", m_url, error);
// FIXME: We may not want to actually remove the cache file for all errors. For now, let's assume the file is not
// useable at this point and remove it.
remove();
if (m_on_pipe_error)
m_on_pipe_error(m_bytes_piped);
close_and_destroy_cache_entry();
}
ErrorOr<void> CacheEntryReader::read_and_validate_footer()
{
TRY(m_file->seek(m_data_offset + m_data_size, SeekMode::SetPosition));
m_cache_footer = TRY(m_file->read_value<CacheFooter>());
if (m_cache_footer.data_size != m_data_size)
return Error::from_string_literal("Invalid data size in footer");
// FIXME: Validate the crc.
return {};
}
}