| /* |
| * Copyright (C) 2020 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "SerializedLogBuffer.h" |
| |
| #include <sys/prctl.h> |
| |
| #include <limits> |
| |
| #include <android-base/logging.h> |
| #include <android-base/scopeguard.h> |
| |
| #include "LogStatistics.h" |
| #include "SerializedFlushToState.h" |
| |
| SerializedLogBuffer::SerializedLogBuffer(LogReaderList* reader_list, LogTags* tags, |
| LogStatistics* stats) |
| : reader_list_(reader_list), tags_(tags), stats_(stats) { |
| Init(); |
| } |
| |
| void SerializedLogBuffer::Init() { |
| log_id_for_each(i) { |
| if (SetSize(i, __android_logger_get_buffer_size(i))) { |
| SetSize(i, LOG_BUFFER_MIN_SIZE); |
| } |
| } |
| |
| // Release any sleeping reader threads to dump their current content. |
| auto reader_threads_lock = std::lock_guard{reader_list_->reader_threads_lock()}; |
| for (const auto& reader_thread : reader_list_->reader_threads()) { |
| reader_thread->triggerReader_Locked(); |
| } |
| } |
| |
| bool SerializedLogBuffer::ShouldLog(log_id_t log_id, const char* msg, uint16_t len) { |
| if (log_id == LOG_ID_SECURITY) { |
| return true; |
| } |
| |
| int prio = ANDROID_LOG_INFO; |
| const char* tag = nullptr; |
| size_t tag_len = 0; |
| if (IsBinary(log_id)) { |
| int32_t tag_int = MsgToTag(msg, len); |
| tag = tags_->tagToName(tag_int); |
| if (tag) { |
| tag_len = strlen(tag); |
| } |
| } else { |
| prio = *msg; |
| tag = msg + 1; |
| tag_len = strnlen(tag, len - 1); |
| } |
| return __android_log_is_loggable_len(prio, tag, tag_len, ANDROID_LOG_VERBOSE); |
| } |
| |
| int SerializedLogBuffer::Log(log_id_t log_id, log_time realtime, uid_t uid, pid_t pid, pid_t tid, |
| const char* msg, uint16_t len) { |
| if (log_id >= LOG_ID_MAX || len == 0) { |
| return -EINVAL; |
| } |
| |
| if (!ShouldLog(log_id, msg, len)) { |
| stats_->AddTotal(log_id, len); |
| return -EACCES; |
| } |
| |
| auto sequence = sequence_.fetch_add(1, std::memory_order_relaxed); |
| |
| auto lock = std::lock_guard{lock_}; |
| |
| if (logs_[log_id].empty()) { |
| logs_[log_id].push_back(SerializedLogChunk(max_size_[log_id] / 4)); |
| } |
| |
| auto total_len = sizeof(SerializedLogEntry) + len; |
| if (!logs_[log_id].back().CanLog(total_len)) { |
| logs_[log_id].back().FinishWriting(); |
| logs_[log_id].push_back(SerializedLogChunk(max_size_[log_id] / 4)); |
| } |
| |
| auto entry = logs_[log_id].back().Log(sequence, realtime, uid, pid, tid, msg, len); |
| stats_->Add(entry->ToLogStatisticsElement(log_id)); |
| |
| MaybePrune(log_id); |
| |
| reader_list_->NotifyNewLog(1 << log_id); |
| return len; |
| } |
| |
| void SerializedLogBuffer::MaybePrune(log_id_t log_id) { |
| size_t total_size = GetSizeUsed(log_id); |
| size_t after_size = total_size; |
| if (total_size > max_size_[log_id]) { |
| Prune(log_id, total_size - max_size_[log_id], 0); |
| after_size = GetSizeUsed(log_id); |
| LOG(INFO) << "Pruned Logs from log_id: " << log_id << ", previous size: " << total_size |
| << " after size: " << after_size; |
| } |
| |
| stats_->set_overhead(log_id, after_size); |
| } |
| |
| void SerializedLogBuffer::RemoveChunkFromStats(log_id_t log_id, SerializedLogChunk& chunk) { |
| chunk.IncReaderRefCount(); |
| int read_offset = 0; |
| while (read_offset < chunk.write_offset()) { |
| auto* entry = chunk.log_entry(read_offset); |
| stats_->Subtract(entry->ToLogStatisticsElement(log_id)); |
| read_offset += entry->total_len(); |
| } |
| chunk.DecReaderRefCount(); |
| } |
| |
| void SerializedLogBuffer::NotifyReadersOfPrune( |
| log_id_t log_id, const std::list<SerializedLogChunk>::iterator& chunk) { |
| for (const auto& reader_thread : reader_list_->reader_threads()) { |
| auto& state = reinterpret_cast<SerializedFlushToState&>(reader_thread->flush_to_state()); |
| state.Prune(log_id, chunk); |
| } |
| } |
| |
| bool SerializedLogBuffer::Prune(log_id_t log_id, size_t bytes_to_free, uid_t uid) { |
| // Don't prune logs that are newer than the point at which any reader threads are reading from. |
| LogReaderThread* oldest = nullptr; |
| auto reader_threads_lock = std::lock_guard{reader_list_->reader_threads_lock()}; |
| for (const auto& reader_thread : reader_list_->reader_threads()) { |
| if (!reader_thread->IsWatching(log_id)) { |
| continue; |
| } |
| if (!oldest || oldest->start() > reader_thread->start() || |
| (oldest->start() == reader_thread->start() && |
| reader_thread->deadline().time_since_epoch().count() != 0)) { |
| oldest = reader_thread.get(); |
| } |
| } |
| |
| auto& log_buffer = logs_[log_id]; |
| auto it = log_buffer.begin(); |
| while (it != log_buffer.end()) { |
| if (oldest != nullptr && it->highest_sequence_number() >= oldest->start()) { |
| break; |
| } |
| |
| // Increment ahead of time since we're going to erase this iterator from the list. |
| auto it_to_prune = it++; |
| |
| // The sequence number check ensures that all readers have read all logs in this chunk, but |
| // they may still hold a reference to the chunk to track their last read log_position. |
| // Notify them to delete the reference. |
| NotifyReadersOfPrune(log_id, it_to_prune); |
| |
| if (uid != 0) { |
| // Reorder the log buffer to remove logs from the given UID. If there are no logs left |
| // in the buffer after the removal, delete it. |
| if (it_to_prune->ClearUidLogs(uid, log_id, stats_)) { |
| log_buffer.erase(it_to_prune); |
| } |
| } else { |
| size_t buffer_size = it_to_prune->PruneSize(); |
| RemoveChunkFromStats(log_id, *it_to_prune); |
| log_buffer.erase(it_to_prune); |
| if (buffer_size >= bytes_to_free) { |
| return true; |
| } |
| bytes_to_free -= buffer_size; |
| } |
| } |
| |
| // If we've deleted all buffers without bytes_to_free hitting 0, then we're called by Clear() |
| // and should return true. |
| if (it == log_buffer.end()) { |
| return true; |
| } |
| |
| // Otherwise we are stuck due to a reader, so mitigate it. |
| CHECK(oldest != nullptr); |
| KickReader(oldest, log_id, bytes_to_free); |
| return false; |
| } |
| |
| // If the selected reader is blocking our pruning progress, decide on |
| // what kind of mitigation is necessary to unblock the situation. |
| void SerializedLogBuffer::KickReader(LogReaderThread* reader, log_id_t id, size_t bytes_to_free) { |
| if (bytes_to_free >= max_size_[id]) { // +100% |
| // A misbehaving or slow reader is dropped if we hit too much memory pressure. |
| LOG(WARNING) << "Kicking blocked reader, " << reader->name() |
| << ", from LogBuffer::kickMe()"; |
| reader->release_Locked(); |
| } else if (reader->deadline().time_since_epoch().count() != 0) { |
| // Allow a blocked WRAP deadline reader to trigger and start reporting the log data. |
| reader->triggerReader_Locked(); |
| } else { |
| // Tell slow reader to skip entries to catch up. |
| unsigned long prune_rows = bytes_to_free / 300; |
| LOG(WARNING) << "Skipping " << prune_rows << " entries from slow reader, " << reader->name() |
| << ", from LogBuffer::kickMe()"; |
| reader->triggerSkip_Locked(id, prune_rows); |
| } |
| } |
| |
| std::unique_ptr<FlushToState> SerializedLogBuffer::CreateFlushToState(uint64_t start, |
| LogMask log_mask) { |
| return std::make_unique<SerializedFlushToState>(start, log_mask); |
| } |
| |
| bool SerializedLogBuffer::FlushTo( |
| LogWriter* writer, FlushToState& abstract_state, |
| const std::function<FilterResult(log_id_t log_id, pid_t pid, uint64_t sequence, |
| log_time realtime)>& filter) { |
| auto lock = std::unique_lock{lock_}; |
| |
| auto& state = reinterpret_cast<SerializedFlushToState&>(abstract_state); |
| state.InitializeLogs(logs_); |
| |
| while (state.HasUnreadLogs()) { |
| MinHeapElement top = state.PopNextUnreadLog(); |
| auto* entry = top.entry; |
| auto log_id = top.log_id; |
| |
| if (entry->sequence() < state.start()) { |
| continue; |
| } |
| state.set_start(entry->sequence()); |
| |
| if (!writer->privileged() && entry->uid() != writer->uid()) { |
| continue; |
| } |
| |
| if (filter) { |
| auto ret = filter(log_id, entry->pid(), entry->sequence(), entry->realtime()); |
| if (ret == FilterResult::kSkip) { |
| continue; |
| } |
| if (ret == FilterResult::kStop) { |
| break; |
| } |
| } |
| |
| lock.unlock(); |
| // We never prune logs equal to or newer than any LogReaderThreads' `start` value, so the |
| // `entry` pointer is safe here without the lock |
| if (!entry->Flush(writer, log_id)) { |
| return false; |
| } |
| lock.lock(); |
| } |
| |
| state.set_start(state.start() + 1); |
| return true; |
| } |
| |
| bool SerializedLogBuffer::Clear(log_id_t id, uid_t uid) { |
| // Try three times to clear, then disconnect the readers and try one final time. |
| for (int retry = 0; retry < 3; ++retry) { |
| { |
| auto lock = std::lock_guard{lock_}; |
| bool prune_success = Prune(id, ULONG_MAX, uid); |
| if (prune_success) { |
| return true; |
| } |
| } |
| sleep(1); |
| } |
| // Check if it is still busy after the sleep, we try to prune one entry, not another clear run, |
| // so we are looking for the quick side effect of the return value to tell us if we have a |
| // _blocked_ reader. |
| bool busy = false; |
| { |
| auto lock = std::lock_guard{lock_}; |
| busy = !Prune(id, 1, uid); |
| } |
| // It is still busy, disconnect all readers. |
| if (busy) { |
| auto reader_threads_lock = std::lock_guard{reader_list_->reader_threads_lock()}; |
| for (const auto& reader_thread : reader_list_->reader_threads()) { |
| if (reader_thread->IsWatching(id)) { |
| LOG(WARNING) << "Kicking blocked reader, " << reader_thread->name() |
| << ", from LogBuffer::clear()"; |
| reader_thread->release_Locked(); |
| } |
| } |
| } |
| auto lock = std::lock_guard{lock_}; |
| return Prune(id, ULONG_MAX, uid); |
| } |
| |
| unsigned long SerializedLogBuffer::GetSizeUsed(log_id_t id) { |
| size_t total_size = 0; |
| for (const auto& chunk : logs_[id]) { |
| total_size += chunk.PruneSize(); |
| } |
| return total_size; |
| } |
| |
| unsigned long SerializedLogBuffer::GetSize(log_id_t id) { |
| auto lock = std::lock_guard{lock_}; |
| return max_size_[id]; |
| } |
| |
| // New SerializedLogChunk objects will be allocated according to the new size, but older one are |
| // unchanged. MaybePrune() is called on the log buffer to reduce it to an appropriate size if the |
| // new size is lower. |
| int SerializedLogBuffer::SetSize(log_id_t id, unsigned long size) { |
| // Reasonable limits ... |
| if (!__android_logger_valid_buffer_size(size)) { |
| return -1; |
| } |
| |
| auto lock = std::lock_guard{lock_}; |
| max_size_[id] = size; |
| |
| MaybePrune(id); |
| |
| return 0; |
| } |