// This file Copyright © 2007-2022 Mnemosyne LLC. // It may be used under GPLv2 (SPDX: GPL-2.0-only), GPLv3 (SPDX: GPL-3.0-only), // or any future license endorsed by Mnemosyne LLC. // License text can be found in the licenses/ folder. #include #include #include #include #include #include #include #include #include #include "transmission.h" #include "benc.h" #include "crypto-utils.h" #include "error-types.h" #include "error.h" #include "file.h" #include "log.h" #include "quark.h" #include "torrent-metainfo.h" #include "tr-assert.h" #include "tr-strbuf.h" #include "utils.h" #include "web-utils.h" using namespace std::literals; //// C BINDINGS #if 0 /// Lifecycle tr_torrent_metainfo* tr_torrentMetainfoNewFromData(char const* data, size_t data_len, struct tr_error** error) { auto* tm = new tr_torrent_metainfo{}; if (!tm->parseBenc(std::string_view{ data, data_len }, error)) { delete tm; return nullptr; } return tm; } tr_torrent_metainfo* tr_torrentMetainfoNewFromFile(char const* filename, struct tr_error** error) { auto* tm = new tr_torrent_metainfo{}; if (!tm->parseBencFromFile(filename ? filename : "", nullptr, error)) { delete tm; return nullptr; } return tm; } void tr_torrentMetainfoFree(tr_torrent_metainfo* tm) { delete tm; } //// Accessors char* tr_torrentMetainfoMagnet(struct tr_torrent_metainfo const* tm) { return tr_strvDup(tm->magnet()); } /// Info tr_torrent_metainfo_info* tr_torrentMetainfoGet(tr_torrent_metainfo const* tm, tr_torrent_metainfo_info* setme) { setme->comment = tm->comment.c_str(); setme->creator = tm->creator.c_str(); setme->info_hash = tm->info_hash; setme->info_hash_string = std::data(tm->info_hash_chars); setme->is_private = tm->is_private; setme->n_pieces = tm->n_pieces; setme->name = tm->name.c_str(); setme->source = tm->source.c_str(); setme->time_created = tm->time_created; setme->total_size = tm->total_size; return setme; } /// Files size_t tr_torrentMetainfoFileCount(tr_torrent_metainfo const* tm) { return std::size(tm->files); } tr_torrent_metainfo_file_info* tr_torrentMetainfoFile( tr_torrent_metainfo const* tm, size_t n, tr_torrent_metainfo_file_info* setme) { auto& file = tm->files[n]; setme->path = file.path.c_str(); setme->size = file.size; return setme; } /// Trackers size_t tr_torrentMetainfoTrackerCount(tr_torrent_metainfo const* tm) { return std::size(tm->trackers); } tr_torrent_metainfo_tracker_info* tr_torrentMetainfoTracker( tr_torrent_metainfo const* tm, size_t n, tr_torrent_metainfo_tracker_info* setme) { auto it = std::begin(tm->trackers); std::advance(it, n); auto const& tracker = it->second; setme->announce_url = tr_quark_get_string(tracker.announce_url); setme->scrape_url = tr_quark_get_string(tracker.scrape_url); setme->tier = tracker.tier; return setme; } #endif /*** **** ***/ /** * @brief Ensure that the URLs for multfile torrents end in a slash. * * See http://bittorrent.org/beps/bep_0019.html#metadata-extension * for background on how the trailing slash is used for "url-list" * fields. * * This function is to workaround some .torrent generators, such as * mktorrent and very old versions of utorrent, that don't add the * trailing slash for multifile torrents if omitted by the end user. */ std::string tr_torrent_metainfo::fixWebseedUrl(tr_torrent_metainfo const& tm, std::string_view url) { url = tr_strvStrip(url); if (tm.fileCount() > 1U && !std::empty(url) && url.back() != '/') { return std::string{ url } + '/'; } return std::string{ url }; } static auto constexpr MaxBencDepth = 32; bool tr_error_is_set(tr_error const* const* error) { return (error != nullptr) && (*error != nullptr); } struct MetainfoHandler final : public transmission::benc::BasicHandler { using BasicHandler = transmission::benc::BasicHandler; tr_torrent_metainfo& tm_; int64_t piece_size_ = 0; int64_t length_ = 0; std::string encoding_ = "UTF-8"; std::string_view info_dict_begin_; tr_tracker_tier_t tier_ = 0; tr_pathbuf file_subpath_; std::string_view pieces_root_; int64_t file_length_ = 0; enum class State { UsePath, FileTree, Files, FilesIgnored, PieceLayers, }; State state_ = State::UsePath; explicit MetainfoHandler(tr_torrent_metainfo& tm) : tm_{ tm } { } bool Key(std::string_view key, Context const& context) override { return BasicHandler::Key(key, context); } bool StartDict(Context const& context) override { if (state_ == State::FileTree) { if (!std::empty(file_subpath_)) { file_subpath_ += '/'; } tr_torrent_files::makeSubpathPortable(currentKey(), file_subpath_); } else if (pathIs(InfoKey)) { info_dict_begin_ = context.raw(); tm_.info_dict_offset_ = context.tokenSpan().first; } else if (pathIs(InfoKey, FileTreeKey)) { state_ = State::FileTree; file_subpath_.clear(); file_length_ = 0; } else if (pathIs(PieceLayersKey)) { state_ = State::PieceLayers; } return BasicHandler::StartDict(context); } bool EndDict(Context const& context) override { BasicHandler::EndDict(context); if (pathIs(InfoKey)) { return finishInfoDict(context); } if (depth() == 0) // top { return finish(context); } if (state_ == State::FileTree) // bittorrent v2 format { if (!addFile(context)) { return false; } file_subpath_.popdir(); if (file_subpath_ == "."sv) { file_subpath_.clear(); } if (pathIs(InfoKey, FileTreeKey)) { state_ = State::UsePath; } } else if (state_ == State::Files) // bittorrent v1 format { if (!addFile(context)) { return false; } file_subpath_.clear(); } return depth() > 0; } bool StartArray(Context const& context) override { if (pathIs(InfoKey, FilesKey)) { state_ = std::empty(tm_.files_) ? State::Files : State::FilesIgnored; file_subpath_.clear(); file_length_ = 0; } return BasicHandler::StartArray(context); } bool EndArray(Context const& context) override { BasicHandler::EndArray(context); if ((state_ == State::Files || state_ == State::FilesIgnored) && currentKey() == FilesKey) // bittorrent v1 format { state_ = State::UsePath; return true; } if (depth() == 2 && key(1) == AnnounceListKey) { ++tier_; } return true; } bool Int64(int64_t value, Context const& /*context*/) override { auto unhandled = bool{ false }; if (state_ == State::FilesIgnored) { // no-op } else if (state_ == State::FileTree || state_ == State::Files) { if (currentKey() == LengthKey) { file_length_ = value; } else if (pathIs(InfoKey, FilesKey, ""sv, MtimeKey)) { // unused by Transmission } else { unhandled = true; } } else if (pathIs(CreationDateKey) || pathIs(InfoKey, CreationDateKey)) { tm_.date_created_ = value; } else if (pathIs(PrivateKey) || pathIs(InfoKey, PrivateKey)) { tm_.is_private_ = value != 0; } else if (pathIs(PieceLengthKey) || pathIs(InfoKey, PieceLengthKey)) { piece_size_ = value; } else if (pathIs(InfoKey, LengthKey)) { length_ = value; } else if (pathIs(InfoKey, MetaVersionKey)) { // currently unused. TODO support for bittorrent v2 // TODO https://github.com/transmission/transmission/issues/458 } else if ( pathIs(DurationKey) || // pathIs(EncodedRateKey) || // pathIs(HeightKey) || // pathIs(InfoKey, EntropyKey) || // pathIs(InfoKey, UniqueKey) || // pathIs(ProfilesKey, HeightKey) || // pathIs(ProfilesKey, WidthKey) || // pathIs(WidthKey) || // pathStartsWith(AzureusPropertiesKey) || // pathStartsWith(InfoKey, FileDurationKey) || // pathStartsWith(InfoKey, FileMediaKey) || // pathStartsWith(InfoKey, ProfilesKey) || // pathStartsWith(LibtorrentResumeKey)) { // unused by Transmission } else { unhandled = true; } if (unhandled) { tr_logAddWarn(fmt::format("unexpected: path '{}', int '{}'", path(), value)); } return true; } bool String(std::string_view value, Context const& context) override { auto const curdepth = depth(); auto const current_key = currentKey(); auto unhandled = bool{ false }; if (state_ == State::FilesIgnored) { // no-op } else if (state_ == State::FileTree) { if (current_key == AttrKey || current_key == PiecesRootKey) { // currently unused. TODO support for bittorrent v2 // TODO https://github.com/transmission/transmission/issues/458 } else { unhandled = true; } } else if (state_ == State::Files) { if (curdepth > 1 && key(curdepth - 1) == PathKey) { if (!std::empty(file_subpath_)) { file_subpath_ += '/'; } tr_torrent_files::makeSubpathPortable(value, file_subpath_); } else if (current_key == AttrKey) { // currently unused. TODO support for bittorrent v2 // TODO https://github.com/transmission/transmission/issues/458 } else if ( pathIs(InfoKey, FilesKey, ""sv, Crc32Key) || // pathIs(InfoKey, FilesKey, ""sv, Ed2kKey) || // pathIs(InfoKey, FilesKey, ""sv, FilehashKey) || // pathIs(InfoKey, FilesKey, ""sv, Md5Key) || // pathIs(InfoKey, FilesKey, ""sv, Md5sumKey) || // pathIs(InfoKey, FilesKey, ""sv, MtimeKey) || // (why a string?) pathIs(InfoKey, FilesKey, ""sv, Sha1Key) || // pathStartsWith(InfoKey, FilesKey, ""sv, PathUtf8Key)) { // unused by Transmission } else { unhandled = true; } } else if (pathIs(CommentKey) || pathIs(CommentUtf8Key)) { tr_strvUtf8Clean(value, tm_.comment_); } else if (pathIs(CreatedByKey) || pathIs(CreatedByUtf8Key)) { tr_strvUtf8Clean(value, tm_.creator_); } else if (pathIs(SourceKey) || pathIs(InfoKey, SourceKey) || pathIs(PublisherKey) || pathIs(InfoKey, PublisherKey)) { // “publisher” is rare, but used by BitComet and appears // to have the same use as the 'source' key // http://wiki.bitcomet.com/inside_bitcomet tr_strvUtf8Clean(value, tm_.source_); } else if (pathIs(AnnounceKey)) { tm_.announceList().add(value, tier_); } else if (pathIs(EncodingKey)) { encoding_ = tr_strvStrip(value); } else if (pathIs(UrlListKey)) { tm_.addWebseed(value); } else if (pathIs(InfoKey, NameKey) || pathIs(InfoKey, NameUtf8Key)) { tr_strvUtf8Clean(value, tm_.name_); } else if (pathIs(InfoKey, PiecesKey)) { auto const n = std::size(value) / sizeof(tr_sha1_digest_t); tm_.pieces_.resize(n); std::copy_n(std::data(value), std::size(value), reinterpret_cast(std::data(tm_.pieces_))); tm_.pieces_offset_ = context.tokenSpan().first; } else if (pathStartsWith(PieceLayersKey)) { // currently unused. TODO support for bittorrent v2 // TODO https://github.com/transmission/transmission/issues/458 } else if (pathStartsWith(AnnounceListKey)) { tm_.announceList().add(value, tier_); } else if (curdepth == 2 && (pathStartsWith(HttpSeedsKey) || pathStartsWith(UrlListKey))) { tm_.addWebseed(value); } else if ( pathIs(ChecksumKey) || // pathIs(ErrCallbackKey) || // pathIs(InfoKey, Ed2kKey) || // pathIs(InfoKey, EntropyKey) || // pathIs(InfoKey, Md5sumKey) || // pathIs(InfoKey, PublisherUrlKey) || // pathIs(InfoKey, Sha1Key) || // pathIs(InfoKey, UniqueKey) || // pathIs(InfoKey, XCrossSeedKey) || // pathIs(LocaleKey) || // pathIs(LogCallbackKey) || // pathIs(PublisherUrlKey) || // pathIs(TitleKey) || // pathStartsWith(AzureusPrivatePropertiesKey) || // pathStartsWith(AzureusPropertiesKey) || // pathStartsWith(InfoKey, CollectionsKey) || // pathStartsWith(InfoKey, FileDurationKey) || // pathStartsWith(InfoKey, ProfilesKey) || // pathStartsWith(LibtorrentResumeKey) || // pathStartsWith(MagnetInfoKey)) { // unused by Transmission } else { unhandled = true; } if (unhandled) { tr_logAddWarn(fmt::format("unexpected: path '{}', str '{}'", path(), value)); } return true; } private: template [[nodiscard]] bool pathStartsWith(Args... args) const noexcept { auto i = 1U; return (depth() >= sizeof...(args)) && ((key(i++) == args) && ...); } template [[nodiscard]] bool pathIs(Args... args) const noexcept { auto i = 1U; return (depth() == sizeof...(args)) && ((key(i++) == args) && ...); } [[nodiscard]] bool addFile(Context const& context) { bool ok = true; if (file_length_ == 0) { return ok; } // FIXME: Check to see if we already added this file. This is a safeguard // for hybrid torrents with duplicate info between "file tree" and "files" if (std::empty(file_subpath_)) { tr_error_set(context.error, EINVAL, fmt::format("invalid path [{:s}]", file_subpath_)); ok = false; } else { tm_.files_.add(file_subpath_, file_length_); } file_length_ = 0; pieces_root_ = {}; // NB: let caller decide how to clear file_tree_. // if we're in "files" mode we clear it; if in "file tree" we pop it return ok; } bool finishInfoDict(Context const& context) { if (std::empty(info_dict_begin_)) { tr_error_set(context.error, EINVAL, "no info_dict found"); return false; } auto root = tr_pathbuf{}; tr_torrent_files::makeSubpathPortable(tm_.name_, root); if (!std::empty(root)) { tm_.files_.insertSubpathPrefix(root); } TR_ASSERT(info_dict_begin_[0] == 'd'); TR_ASSERT(context.raw().back() == 'e'); char const* const begin = &info_dict_begin_.front(); char const* const end = &context.raw().back() + 1; auto const info_dict_benc = std::string_view{ begin, size_t(end - begin) }; auto const hash = tr_sha1(info_dict_benc); if (!hash) { tr_error_set(context.error, EINVAL, "bad info_dict checksum"); return false; } tm_.info_hash_ = *hash; tm_.info_hash_str_ = tr_sha1_to_string(tm_.info_hash_); tm_.info_dict_size_ = std::size(info_dict_benc); return true; } bool finish(Context const& context) { // bittorrent 1.0 spec // http://bittorrent.org/beps/bep_0003.html // // "There is also a key length or a key files, but not both or neither. // // "If length is present then the download represents a single file, // otherwise it represents a set of files which go in a directory structure. // In the single file case, length maps to the length of the file in bytes. if (tm_.fileCount() == 0 && length_ != 0 && !std::empty(tm_.name_)) { tm_.files_.add(tm_.name_, length_); } if (tm_.fileCount() == 0) { if (!tr_error_is_set(context.error)) { tr_error_set(context.error, EINVAL, "no files found"); } return false; } if (piece_size_ == 0) { if (!tr_error_is_set(context.error)) { tr_error_set(context.error, EINVAL, fmt::format("invalid piece size: {}", piece_size_)); } return false; } tm_.block_info_.initSizes(tm_.files_.totalSize(), piece_size_); return true; } static constexpr std::string_view AcodecKey = "acodec"sv; static constexpr std::string_view AnnounceKey = "announce"sv; static constexpr std::string_view AnnounceListKey = "announce-list"sv; static constexpr std::string_view AttrKey = "attr"sv; static constexpr std::string_view AzureusPrivatePropertiesKey = "azureus_private_properties"sv; static constexpr std::string_view AzureusPropertiesKey = "azureus_properties"sv; static constexpr std::string_view ChecksumKey = "checksum"sv; static constexpr std::string_view CollectionsKey = "collections"sv; static constexpr std::string_view CommentKey = "comment"sv; static constexpr std::string_view CommentUtf8Key = "comment.utf-8"sv; static constexpr std::string_view Crc32Key = "crc32"sv; static constexpr std::string_view CreatedByKey = "created by"sv; static constexpr std::string_view CreatedByUtf8Key = "created by.utf-8"sv; static constexpr std::string_view CreationDateKey = "creation date"sv; static constexpr std::string_view DurationKey = "duration"sv; static constexpr std::string_view Ed2kKey = "ed2k"sv; static constexpr std::string_view EncodedRateKey = "encoded rate"sv; static constexpr std::string_view EncodingKey = "encoding"sv; static constexpr std::string_view EntropyKey = "entropy"sv; static constexpr std::string_view ErrCallbackKey = "err_callback"sv; static constexpr std::string_view FileDurationKey = "file-duration"sv; static constexpr std::string_view FileMediaKey = "file-media"sv; static constexpr std::string_view FileTreeKey = "file tree"sv; static constexpr std::string_view FilehashKey = "filehash"sv; static constexpr std::string_view FilesKey = "files"sv; static constexpr std::string_view HeightKey = "height"sv; static constexpr std::string_view HttpSeedsKey = "httpseeds"sv; static constexpr std::string_view InfoKey = "info"sv; static constexpr std::string_view LengthKey = "length"sv; static constexpr std::string_view LibtorrentResumeKey = "libtorrent_resume"sv; static constexpr std::string_view LocaleKey = "locale"sv; static constexpr std::string_view LogCallbackKey = "log_callback"sv; static constexpr std::string_view MagnetInfoKey = "magnet-info"sv; static constexpr std::string_view Md5Key = "md5"sv; static constexpr std::string_view Md5sumKey = "md5sum"sv; static constexpr std::string_view MetaVersionKey = "meta version"sv; static constexpr std::string_view MtimeKey = "mtime"sv; static constexpr std::string_view NameKey = "name"sv; static constexpr std::string_view NameUtf8Key = "name.utf-8"sv; static constexpr std::string_view PathKey = "path"sv; static constexpr std::string_view PathUtf8Key = "path.utf-8"sv; static constexpr std::string_view PieceLayersKey = "piece layers"sv; static constexpr std::string_view PieceLengthKey = "piece length"sv; static constexpr std::string_view PiecesKey = "pieces"sv; static constexpr std::string_view PiecesRootKey = "pieces root"sv; static constexpr std::string_view PrivateKey = "private"sv; static constexpr std::string_view ProfilesKey = "profiles"sv; static constexpr std::string_view PublisherKey = "publisher"sv; static constexpr std::string_view PublisherUrlKey = "publisher-url"sv; static constexpr std::string_view Sha1Key = "sha1"sv; static constexpr std::string_view SourceKey = "source"sv; static constexpr std::string_view TitleKey = "title"sv; static constexpr std::string_view UniqueKey = "unique"sv; static constexpr std::string_view UrlListKey = "url-list"sv; static constexpr std::string_view VcodecKey = "vcodec"sv; static constexpr std::string_view WidthKey = "width"sv; static constexpr std::string_view XCrossSeedKey = "x_cross_seed"sv; }; bool tr_torrent_metainfo::parseBenc(std::string_view benc, tr_error** error) { auto stack = transmission::benc::ParserStack{}; auto handler = MetainfoHandler{ *this }; tr_error* my_error = nullptr; if (error == nullptr) { error = &my_error; } auto const ok = transmission::benc::parse(benc, stack, handler, nullptr, error); if (tr_error_is_set(error)) { tr_logAddError(fmt::format("{} ({})", (*error)->message, (*error)->code)); } tr_error_clear(&my_error); if (!ok) { return false; } if (std::empty(name_)) { // TODO from first file } return true; } bool tr_torrent_metainfo::parseTorrentFile(std::string_view filename, std::vector* contents, tr_error** error) { auto local_contents = std::vector{}; if (contents == nullptr) { contents = &local_contents; } return tr_loadFile(filename, *contents, error) && parseBenc({ std::data(*contents), std::size(*contents) }, error); } tr_sha1_digest_t const& tr_torrent_metainfo::pieceHash(tr_piece_index_t piece) const { return this->pieces_[piece]; } tr_pathbuf tr_torrent_metainfo::makeFilename( std::string_view dirname, std::string_view name, std::string_view info_hash_string, BasenameFormat format, std::string_view suffix) { // `${dirname}/${name}.${info_hash}${suffix}` // `${dirname}/${info_hash}${suffix}` return format == BasenameFormat::Hash ? tr_pathbuf{ dirname, '/', info_hash_string, suffix } : tr_pathbuf{ dirname, '/', name, '.', info_hash_string.substr(0, 16), suffix }; } bool tr_torrent_metainfo::migrateFile( std::string_view dirname, std::string_view name, std::string_view info_hash_string, std::string_view suffix) { auto const old_filename = makeFilename(dirname, name, info_hash_string, BasenameFormat::NameAndPartialHash, suffix); auto const old_filename_exists = tr_sys_path_exists(old_filename); auto const new_filename = makeFilename(dirname, name, info_hash_string, BasenameFormat::Hash, suffix); auto const new_filename_exists = tr_sys_path_exists(new_filename); if (old_filename_exists && new_filename_exists) { tr_sys_path_remove(old_filename); return false; } if (new_filename_exists) { return false; } if (old_filename_exists && tr_sys_path_rename(old_filename, new_filename)) { tr_logAddError( fmt::format( _("Migrated torrent file from '{old_path}' to '{path}'"), fmt::arg("old_path", old_filename), fmt::arg("path", new_filename)), name); return true; } return false; // neither file exists } void tr_torrent_metainfo::removeFile( std::string_view dirname, std::string_view name, std::string_view info_hash_string, std::string_view suffix) { auto filename = makeFilename(dirname, name, info_hash_string, BasenameFormat::NameAndPartialHash, suffix); tr_sys_path_remove(filename, nullptr); filename = makeFilename(dirname, name, info_hash_string, BasenameFormat::Hash, suffix); tr_sys_path_remove(filename, nullptr); }