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tdlight/td/telegram/files/FileDownloader.cpp
Arseny Smirnov 9310e29ff4 Check hash of local files with same name, before download 
GitOrigin-RevId: ad97f6df43eb022d5c122a950081c5d7700820f5
2018-02-26 13:05:14 +03:00

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//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2018
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#include "td/telegram/files/FileDownloader.h"
#include "td/telegram/telegram_api.h"
#include "td/telegram/files/FileLoaderUtils.h"
#include "td/telegram/Global.h"
#include "td/telegram/UniqueId.h"
#include "td/utils/buffer.h"
#include "td/utils/common.h"
#include "td/utils/crypto.h"
#include "td/utils/format.h"
#include "td/utils/logging.h"
#include "td/utils/misc.h"
#include "td/utils/ScopeGuard.h"
#include "td/utils/Slice.h"
#include <tuple>
namespace td {
FileDownloader::FileDownloader(const FullRemoteFileLocation &remote, const LocalFileLocation &local, int64 size,
string name, const FileEncryptionKey &encryption_key, bool is_small, bool search_file,
std::unique_ptr<Callback> callback)
: remote_(remote)
, local_(local)
, size_(size)
, name_(std::move(name))
, encryption_key_(encryption_key)
, callback_(std::move(callback))
, is_small_(is_small)
, search_file_(search_file) {
if (!encryption_key.empty()) {
set_ordered_flag(true);
}
}
Result<FileLoader::FileInfo> FileDownloader::init() {
SCOPE_EXIT {
try_release_fd();
};
if (local_.type() == LocalFileLocation::Type::Full) {
return Status::Error("File is already downloaded");
}
int ready_part_count = 0;
int32 part_size = 0;
if (local_.type() == LocalFileLocation::Type::Partial) {
const auto &partial = local_.partial();
path_ = partial.path_;
auto result_fd = FileFd::open(path_, FileFd::Write | FileFd::Read);
// TODO: check timestamps..
if (result_fd.is_ok()) {
if (!encryption_key_.empty()) {
CHECK(partial.iv_.size() == 32) << partial.iv_.size();
encryption_key_.mutable_iv() = as<UInt256>(partial.iv_.data());
next_part_ = partial.ready_part_count_;
}
fd_ = result_fd.move_as_ok();
part_size = partial.part_size_;
ready_part_count = partial.ready_part_count_;
}
}
if (search_file_ && fd_.empty() && size_ > 0 && size_ < 1000 * (1 << 20) && encryption_key_.empty() &&
!remote_.is_web()) {
[&] {
TRY_RESULT(path, search_file(get_files_dir(remote_.file_type_), name_, size_));
TRY_RESULT(fd, FileFd::open(path, FileFd::Read));
LOG(INFO) << "Check hash of local file " << path;
path_ = std::move(path);
fd_ = std::move(fd);
need_check_ = true;
only_check_ = true;
part_size = 32 * (1 << 10);
ready_part_count = narrow_cast<int>((size_ + part_size - 1) / part_size);
return Status::OK();
}();
}
std::vector<int> parts(ready_part_count);
for (int i = 0; i < ready_part_count; i++) {
parts[i] = i;
}
FileInfo res;
res.size = size_;
res.is_size_final = true;
res.part_size = part_size;
res.ready_parts = std::move(parts);
res.use_part_count_limit = false;
res.only_check_ = only_check_;
return res;
}
Status FileDownloader::on_ok(int64 size) {
auto dir = get_files_dir(remote_.file_type_);
std::string path;
if (only_check_) {
path = path_;
} else {
TRY_RESULT(perm_path, create_from_temp(path_, dir, name_));
path = std::move(perm_path);
}
fd_.close();
callback_->on_ok(FullLocalFileLocation(remote_.file_type_, std::move(path), 0), size);
return Status::OK();
}
void FileDownloader::on_error(Status status) {
fd_.close();
callback_->on_error(std::move(status));
}
Result<bool> FileDownloader::should_restart_part(Part part, NetQueryPtr &net_query) {
// Check if we should use CDN or reupload file to CDN
if (net_query->is_error()) {
if (net_query->error().message() == "FILE_TOKEN_INVALID") {
use_cdn_ = false;
return true;
}
if (net_query->error().message() == "REQUEST_TOKEN_INVALID") {
return true;
}
return false;
}
switch (narrow_cast<QueryType>(UniqueId::extract_key(net_query->id()))) {
case QueryType::Default: {
if (net_query->ok_tl_constructor() == telegram_api::upload_fileCdnRedirect::ID) {
LOG(DEBUG) << part.id << " got REDIRECT";
TRY_RESULT(file_base, fetch_result<telegram_api::upload_getFile>(net_query->ok()));
CHECK(file_base->get_id() == telegram_api::upload_fileCdnRedirect::ID);
auto file = move_tl_object_as<telegram_api::upload_fileCdnRedirect>(file_base);
auto new_cdn_file_token = file->file_token_.as_slice();
if (cdn_file_token_ == new_cdn_file_token) {
return true;
}
use_cdn_ = true;
need_check_ = true;
cdn_file_token_generation_++;
cdn_file_token_ = new_cdn_file_token.str();
cdn_dc_id_ = DcId::external(file->dc_id_);
cdn_encryption_key_ = file->encryption_key_.as_slice().str();
cdn_encryption_iv_ = file->encryption_iv_.as_slice().str();
add_hash_info(file->file_hashes_);
if (cdn_encryption_iv_.size() != 16 || cdn_encryption_key_.size() != 32) {
return Status::Error("Wrong ctr key or iv size");
}
return true;
}
return false;
}
case QueryType::ReuploadCDN: {
TRY_RESULT(file_hashes, fetch_result<telegram_api::upload_reuploadCdnFile>(net_query->ok()));
add_hash_info(file_hashes);
LOG(DEBUG) << part.id << " got REUPLOAD_OK";
return true;
}
case QueryType::CDN: {
if (net_query->ok_tl_constructor() == telegram_api::upload_cdnFileReuploadNeeded::ID) {
LOG(DEBUG) << part.id << " got REUPLOAD";
TRY_RESULT(file_base, fetch_result<telegram_api::upload_getCdnFile>(net_query->ok()));
CHECK(file_base->get_id() == telegram_api::upload_cdnFileReuploadNeeded::ID);
auto file = move_tl_object_as<telegram_api::upload_cdnFileReuploadNeeded>(file_base);
cdn_part_reupload_token_[part.id] = file->request_token_.as_slice().str();
return true;
}
auto it = cdn_part_file_token_generation_.find(part.id);
CHECK(it != cdn_part_file_token_generation_.end());
if (it->second != cdn_file_token_generation_) {
LOG(DEBUG) << part.id << " got part with old file_token";
return true;
}
return false;
}
default:
UNREACHABLE();
}
return false;
}
Result<std::pair<NetQueryPtr, bool>> FileDownloader::start_part(Part part, int32 part_count) {
if (!encryption_key_.empty()) {
part.size = (part.size + 15) & ~15; // fix for last part
}
// auto size = part.size;
//// sometimes we can ask more than server has, just to check size
// if (size < get_part_size()) {
// size = min(size + 16, get_part_size());
// LOG(INFO) << "Ask " << size << " instead of " << part.size;
//}
auto size = get_part_size();
CHECK(part.size <= size);
callback_->on_start_download();
NetQueryPtr net_query;
if (!use_cdn_) {
net_query = G()->net_query_creator().create(
UniqueId::next(UniqueId::Type::Default, static_cast<uint8>(QueryType::Default)),
remote_.is_web()
? create_storer(telegram_api::upload_getWebFile(remote_.as_input_web_file_location(),
static_cast<int32>(part.offset), static_cast<int32>(size)))
: create_storer(telegram_api::upload_getFile(remote_.as_input_file_location(),
static_cast<int32>(part.offset), static_cast<int32>(size))),
remote_.get_dc_id(), is_small_ ? NetQuery::Type::DownloadSmall : NetQuery::Type::Download);
} else {
if (remote_.is_web()) {
return Status::Error("Can't download web file from CDN");
}
auto it = cdn_part_reupload_token_.find(part.id);
if (it == cdn_part_reupload_token_.end()) {
auto query = telegram_api::upload_getCdnFile(BufferSlice(cdn_file_token_), static_cast<int32>(part.offset),
static_cast<int32>(size));
cdn_part_file_token_generation_[part.id] = cdn_file_token_generation_;
LOG(DEBUG) << part.id << " " << to_string(query);
net_query = G()->net_query_creator().create(
UniqueId::next(UniqueId::Type::Default, static_cast<uint8>(QueryType::CDN)), create_storer(query), cdn_dc_id_,
is_small_ ? NetQuery::Type::DownloadSmall : NetQuery::Type::Download, NetQuery::AuthFlag::Off);
} else {
auto query = telegram_api::upload_reuploadCdnFile(BufferSlice(cdn_file_token_), BufferSlice(it->second));
LOG(DEBUG) << part.id << " " << to_string(query);
net_query = G()->net_query_creator().create(
UniqueId::next(UniqueId::Type::Default, static_cast<uint8>(QueryType::ReuploadCDN)), create_storer(query),
remote_.get_dc_id(), is_small_ ? NetQuery::Type::DownloadSmall : NetQuery::Type::Download,
NetQuery::AuthFlag::On);
cdn_part_reupload_token_.erase(it);
}
}
net_query->file_type_ = narrow_cast<int32>(remote_.file_type_);
return std::make_pair(std::move(net_query), false);
}
Result<size_t> FileDownloader::process_part(Part part, NetQueryPtr net_query) {
if (net_query->is_error()) {
return std::move(net_query->error());
}
BufferSlice bytes;
bool need_cdn_decrypt = false;
auto query_type = narrow_cast<QueryType>(UniqueId::extract_key(net_query->id()));
switch (query_type) {
case QueryType::Default: {
if (remote_.is_web()) {
TRY_RESULT(file, fetch_result<telegram_api::upload_getWebFile>(net_query->ok()));
bytes = std::move(file->bytes_);
} else {
TRY_RESULT(file_base, fetch_result<telegram_api::upload_getFile>(net_query->ok()));
CHECK(file_base->get_id() == telegram_api::upload_file::ID);
auto file = move_tl_object_as<telegram_api::upload_file>(file_base);
LOG(DEBUG) << part.id << " upload_getFile result";
bytes = std::move(file->bytes_);
}
break;
}
case QueryType::CDN: {
TRY_RESULT(file_base, fetch_result<telegram_api::upload_getCdnFile>(net_query->ok()));
CHECK(file_base->get_id() == telegram_api::upload_cdnFile::ID);
auto file = move_tl_object_as<telegram_api::upload_cdnFile>(file_base);
LOG(DEBUG) << part.id << " upload_getCdnFile result";
bytes = std::move(file->bytes_);
need_cdn_decrypt = true;
break;
}
default:
UNREACHABLE();
}
auto padded_size = part.size;
if (!encryption_key_.empty()) {
padded_size = (part.size + 15) & ~15;
}
LOG(INFO) << "Got " << bytes.size() << " padded_size=" << padded_size;
if (bytes.size() > padded_size) {
return Status::Error("Part size is more than requested");
}
if (bytes.empty()) {
return 0;
}
// Encryption
if (need_cdn_decrypt) {
auto iv = as<UInt128>(cdn_encryption_iv_.c_str());
CHECK(part.offset % 16 == 0);
auto offset = narrow_cast<uint32>(part.offset / 16);
offset =
((offset & 0xff) << 24) | ((offset & 0xff00) << 8) | ((offset & 0xff0000) >> 8) | ((offset & 0xff000000) >> 24);
as<uint32>(iv.raw + 12) = offset;
auto key = as<UInt256>(cdn_encryption_key_.c_str());
AesCtrState ctr_state;
ctr_state.init(key, iv);
ctr_state.decrypt(bytes.as_slice(), bytes.as_slice());
}
if (!encryption_key_.empty()) {
CHECK(next_part_ == part.id) << tag("expected part.id", next_part_) << "!=" << tag("part.id", part.id);
CHECK(!next_part_stop_);
next_part_++;
if (part.size % 16 != 0) {
next_part_stop_ = true;
}
aes_ige_decrypt(encryption_key_.key(), &encryption_key_.mutable_iv(), bytes.as_slice(), bytes.as_slice());
}
auto slice = bytes.as_slice().truncate(part.size);
TRY_STATUS(acquire_fd());
TRY_RESULT(written, fd_.pwrite(slice, part.offset));
// may write less than part.size, when size of downloadable file is unknown
if (written != slice.size()) {
return Status::Error("Failed to save file part to the file");
}
return written;
}
void FileDownloader::on_progress(int32 part_count, int32 part_size, int32 ready_part_count, bool is_ready,
int64 ready_size) {
if (is_ready) {
// do not send partial location. will lead to wrong local_size
return;
}
if (ready_size == 0 || path_.empty()) {
return;
}
if (encryption_key_.empty()) {
callback_->on_partial_download(PartialLocalFileLocation{remote_.file_type_, path_, part_size, ready_part_count, ""},
ready_size);
} else {
UInt256 iv;
if (ready_part_count == next_part_) {
iv = encryption_key_.mutable_iv();
} else {
LOG(FATAL) << tag("ready_part_count", ready_part_count) << tag("next_part", next_part_);
}
callback_->on_partial_download(PartialLocalFileLocation{remote_.file_type_, path_, part_size, ready_part_count,
Slice(iv.raw, sizeof(iv)).str()},
ready_size);
}
}
FileLoader::Callback *FileDownloader::get_callback() {
return static_cast<FileLoader::Callback *>(callback_.get());
}
Status FileDownloader::process_check_query(NetQueryPtr net_query) {
has_hash_query_ = false;
TRY_RESULT(file_hashes, fetch_result<telegram_api::upload_getCdnFileHashes>(std::move(net_query)));
add_hash_info(file_hashes);
return Status::OK();
}
Result<FileLoader::CheckInfo> FileDownloader::check_loop(int64 checked_prefix_size, int64 ready_prefix_size,
bool is_ready) {
if (!need_check_) {
return CheckInfo{};
}
SCOPE_EXIT {
try_release_fd();
};
CheckInfo info;
while (checked_prefix_size < ready_prefix_size) {
//LOG(ERROR) << "NEED TO CHECK: " << checked_prefix_size << "->" << ready_prefix_size - checked_prefix_size;
HashInfo search_info;
search_info.offset = checked_prefix_size;
auto it = hash_info_.upper_bound(search_info);
if (it != hash_info_.begin()) {
it--;
}
if (it != hash_info_.end() && it->offset <= checked_prefix_size &&
it->offset + narrow_cast<int64>(it->size) > checked_prefix_size) {
int64 begin_offset = it->offset;
int64 end_offset = it->offset + narrow_cast<int64>(it->size);
if (ready_prefix_size < end_offset) {
if (!is_ready) {
break;
}
end_offset = ready_prefix_size;
}
size_t size = narrow_cast<size_t>(end_offset - begin_offset);
auto slice = BufferSlice(size);
TRY_STATUS(acquire_fd());
TRY_RESULT(read_size, fd_.pread(slice.as_slice(), begin_offset));
if (size != read_size) {
return Status::Error("Failed to read file to check hash");
}
string hash(32, ' ');
sha256(slice.as_slice(), hash);
if (hash != it->hash) {
if (only_check_) {
return Status::Error("FILE_DOWNLOAD_RESTART");
}
return Status::Error("Hash mismatch");
}
checked_prefix_size = end_offset;
info.changed = true;
continue;
}
if (!has_hash_query_) {
has_hash_query_ = true;
auto query =
telegram_api::upload_getFileHashes(remote_.as_input_file_location(), narrow_cast<int32>(checked_prefix_size));
auto net_query = G()->net_query_creator().create(
create_storer(query), remote_.get_dc_id(),
is_small_ ? NetQuery::Type::DownloadSmall : NetQuery::Type::Download, NetQuery::AuthFlag::On);
info.queries.push_back(std::move(net_query));
break;
}
// Should fail?
break;
}
info.need_check = need_check_;
info.checked_prefix_size = checked_prefix_size;
return std::move(info);
}
void FileDownloader::add_hash_info(const std::vector<telegram_api::object_ptr<telegram_api::fileHash>> &hashes) {
for (auto &hash : hashes) {
//LOG(ERROR) << "ADD HASH " << hash->offset_ << "->" << hash->limit_;
HashInfo hash_info;
hash_info.size = hash->limit_;
hash_info.offset = hash->offset_;
hash_info.hash = hash->hash_.as_slice().str();
hash_info_.insert(std::move(hash_info));
}
}
void FileDownloader::keep_fd_flag(bool keep_fd) {
keep_fd_ = keep_fd;
try_release_fd();
}
void FileDownloader::try_release_fd() {
if (!keep_fd_ && !fd_.empty()) {
fd_.close();
}
}
Status FileDownloader::acquire_fd() {
if (fd_.empty()) {
if (path_.empty()) {
TRY_RESULT(file_path, open_temp_file(remote_.file_type_));
std::tie(fd_, path_) = std::move(file_path);
} else {
TRY_RESULT(fd, FileFd::open(path_, (only_check_ ? 0 : FileFd::Write) | FileFd::Read));
fd_ = std::move(fd);
}
}
return Status::OK();
}
} // namespace td
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