Merge "logd: don't poll() before recvmsg()" am: bf3b47a031 am: de2a239467 am:... (8b2fadd9) · Commits · e / os / android_system_core

logd/LogListener.cpp

+33 −17

Original line number	Diff line number	Diff line
		@@ -22,6 +22,8 @@
		#include <sys/un.h>
		#include <unistd.h>

		#include <thread>

		#include <cutils/sockets.h>
		#include <private/android_filesystem_config.h>
		#include <private/android_logger.h>
		@@ -31,17 +33,33 @@
		#include "LogUtils.h"

		LogListener::LogListener(LogBuffer* buf, LogReader* reader)
		: SocketListener(getLogSocket(), false), logbuf(buf), reader(reader) {}
		: socket_(GetLogSocket()), logbuf_(buf), reader_(reader) {}

		bool LogListener::StartListener() {
		if (socket_ <= 0) {
		return false;
		}
		auto thread = std::thread(&LogListener::ThreadFunction, this);
		thread.detach();
		return true;
		}

		bool LogListener::onDataAvailable(SocketClient* cli) {
		void LogListener::ThreadFunction() {
		static bool name_set;
		if (!name_set) {
		prctl(PR_SET_NAME, "logd.writer");
		name_set = true;
		}

		while (true) {
		HandleData();
		}
		}

		void LogListener::HandleData() {
		// + 1 to ensure null terminator if MAX_PAYLOAD buffer is received
		char buffer[sizeof(android_log_header_t) + LOGGER_ENTRY_MAX_PAYLOAD + 1];
		__attribute__((uninitialized)) char
		buffer[sizeof(android_log_header_t) + LOGGER_ENTRY_MAX_PAYLOAD + 1];
		struct iovec iov = {buffer, sizeof(buffer) - 1};

		alignas(4) char control[CMSG_SPACE(sizeof(struct ucred))];
		@@ -49,15 +67,13 @@ bool LogListener::onDataAvailable(SocketClient* cli) {
		nullptr, 0, &iov, 1, control, sizeof(control), 0,
		};

		int socket = cli->getSocket();

		// To clear the entire buffer is secure/safe, but this contributes to 1.68%
		// overhead under logging load. We are safe because we check counts, but
		// still need to clear null terminator
		// memset(buffer, 0, sizeof(buffer));
		ssize_t n = recvmsg(socket, &hdr, 0);
		ssize_t n = recvmsg(socket_, &hdr, 0);
		if (n <= (ssize_t)(sizeof(android_log_header_t))) {
		return false;
		return;
		}

		buffer[n] = 0;
		@@ -75,14 +91,14 @@ bool LogListener::onDataAvailable(SocketClient* cli) {
		}

		if (cred == nullptr) {
		return false;
		return;
		}

		if (cred->uid == AID_LOGD) {
		// ignore log messages we send to ourself.
		// Such log messages are often generated by libraries we depend on
		// which use standard Android logging.
		return false;
		return;
		}

		android_log_header_t* header =
		@@ -90,13 +106,13 @@ bool LogListener::onDataAvailable(SocketClient* cli) {
		log_id_t logId = static_cast<log_id_t>(header->id);
		if (/* logId < LOG_ID_MIN \|\| */ logId >= LOG_ID_MAX \|\|
		logId == LOG_ID_KERNEL) {
		return false;
		return;
		}

		if ((logId == LOG_ID_SECURITY) &&
		(!__android_log_security() \|\|
		!clientHasLogCredentials(cred->uid, cred->gid, cred->pid))) {
		return false;
		return;
		}

		char* msg = ((char*)buffer) + sizeof(android_log_header_t);
		@@ -105,16 +121,16 @@ bool LogListener::onDataAvailable(SocketClient* cli) {
		// NB: hdr.msg_flags & MSG_TRUNC is not tested, silently passing a
		// truncated message to the logs.

		int res = logbuf->log(logId, header->realtime, cred->uid, cred->pid, header->tid, msg,
		int res = logbuf_->log(logId, header->realtime, cred->uid, cred->pid, header->tid, msg,
		((size_t)n <= UINT16_MAX) ? (uint16_t)n : UINT16_MAX);
		if (res > 0) {
		reader->notifyNewLog(static_cast<unsigned int>(1 << logId));
		reader_->notifyNewLog(static_cast<unsigned int>(1 << logId));
		}

		return true;
		return;
		}

		int LogListener::getLogSocket() {
		int LogListener::GetLogSocket() {
		static const char socketName[] = "logdw";
		int sock = android_get_control_socket(socketName);

logd/LogListener.h

+13 −15

Original line number	Diff line number	Diff line
		@@ -14,24 +14,22 @@
		* limitations under the License.
		*/

		#ifndef _LOGD_LOG_LISTENER_H__
		#define _LOGD_LOG_LISTENER_H__
		#pragma once

		#include <sysutils/SocketListener.h>
		#include "LogBuffer.h"
		#include "LogReader.h"

		class LogListener : public SocketListener {
		LogBuffer* logbuf;
		LogReader* reader;

		class LogListener {
		public:
		LogListener(LogBuffer* buf, LogReader* reader);

		protected:
		virtual bool onDataAvailable(SocketClient* cli);
		bool StartListener();

		private:
		static int getLogSocket();
		};
		void ThreadFunction();
		void HandleData();
		static int GetLogSocket();

		#endif
		int socket_;
		LogBuffer* logbuf_;
		LogReader* reader_;
		};

logd/main.cpp

+1 −2

Original line number	Diff line number	Diff line
		@@ -304,8 +304,7 @@ int main(int argc, char* argv[]) {
		// and LogReader is notified to send updates to connected clients.

		LogListener* swl = new LogListener(logBuf, reader);
		// Backlog and /proc/sys/net/unix/max_dgram_qlen set to large value
		if (swl->startListener(600)) {
		if (!swl->StartListener()) {
		return EXIT_FAILURE;
		}