logd: add a SerializedLogBuffer suitable for compression
Initial commit for a SerializedLogBuffer. The intention here is for
the serialized data to be compressed (currently using zlib) to allow
for substantially longer logs in the same memory footprint.
Test: unit tests
Change-Id: I2528e4e1ff1cf3bc91130173a107f371f04d911a
diff --git a/logd/SerializedLogEntry.h b/logd/SerializedLogEntry.h
new file mode 100644
index 0000000..f599abe
--- /dev/null
+++ b/logd/SerializedLogEntry.h
@@ -0,0 +1,98 @@
+/*
+ * 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.
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <sys/types.h>
+
+#include <log/log.h>
+#include <log/log_read.h>
+
+#include "LogStatistics.h"
+#include "LogWriter.h"
+
+// These structs are packed into a single chunk of memory for each log type within a
+// SerializedLogChunk object. Their message is contained immediately at the end of the struct. The
+// address of the next log in the buffer is *this + sizeof(SerializedLogEntry) + msg_len_. If that
+// value would overflow the chunk of memory associated with the SerializedLogChunk object, then a
+// new SerializedLogChunk must be allocated to contain the next SerializedLogEntry.
+class __attribute__((packed)) SerializedLogEntry {
+ public:
+ SerializedLogEntry(uid_t uid, pid_t pid, pid_t tid, uint64_t sequence, log_time realtime,
+ uint16_t len)
+ : uid_(uid),
+ pid_(pid),
+ tid_(tid),
+ sequence_(sequence),
+ realtime_(realtime),
+ msg_len_(len) {}
+ SerializedLogEntry(const SerializedLogEntry& elem) = delete;
+ SerializedLogEntry& operator=(const SerializedLogEntry& elem) = delete;
+ ~SerializedLogEntry() {
+ // Never place anything in this destructor. This class is in place constructed and never
+ // destructed.
+ }
+
+ LogStatisticsElement ToLogStatisticsElement(log_id_t log_id) const {
+ return LogStatisticsElement{
+ .uid = uid(),
+ .pid = pid(),
+ .tid = tid(),
+ .tag = IsBinary(log_id) ? MsgToTag(msg(), msg_len()) : 0,
+ .realtime = realtime(),
+ .msg = msg(),
+ .msg_len = msg_len(),
+ .dropped_count = 0,
+ .log_id = log_id,
+ };
+ }
+
+ bool Flush(LogWriter* writer, log_id_t log_id) const {
+ struct logger_entry entry = {};
+
+ entry.hdr_size = sizeof(struct logger_entry);
+ entry.lid = log_id;
+ entry.pid = pid();
+ entry.tid = tid();
+ entry.uid = uid();
+ entry.sec = realtime().tv_sec;
+ entry.nsec = realtime().tv_nsec;
+ entry.len = msg_len();
+
+ return writer->Write(entry, msg());
+ }
+
+ uid_t uid() const { return uid_; }
+ pid_t pid() const { return pid_; }
+ pid_t tid() const { return tid_; }
+ uint16_t msg_len() const { return msg_len_; }
+ uint64_t sequence() const { return sequence_; }
+ log_time realtime() const { return realtime_; }
+
+ char* msg() { return reinterpret_cast<char*>(this) + sizeof(*this); }
+ const char* msg() const { return reinterpret_cast<const char*>(this) + sizeof(*this); }
+ uint16_t total_len() const { return sizeof(*this) + msg_len_; }
+
+ private:
+ const uint32_t uid_;
+ const uint32_t pid_;
+ const uint32_t tid_;
+ const uint64_t sequence_;
+ const log_time realtime_;
+ const uint16_t msg_len_;
+};