logd/LogReader.cpp - platform/system/logging - Git at Google

 /*
  * Copyright (C) 2012-2013 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 <ctype.h>
 #include <inttypes.h>
 #include <poll.h>
 #include <sched.h>
 #include <sys/prctl.h>
 #include <sys/socket.h>
 #include <sys/types.h>

 #include <chrono>

 #include <android-base/logging.h>
 #include <android-base/stringprintf.h>
 #include <cutils/sockets.h>
 #include <private/android_filesystem_config.h>
 #include <private/android_logger.h>

 #include "LogBuffer.h"
 #include "LogBufferElement.h"
 #include "LogPermissions.h"
 #include "LogReader.h"
 #include "LogUtils.h"
 #include "LogWriter.h"

 static bool CanReadSecurityLogs(SocketClient* client) {
     return client->getUid() == AID_SYSTEM || client->getGid() == AID_SYSTEM;
 }

 static std::string SocketClientToName(SocketClient* client) {
     return android::base::StringPrintf("pid %d, fd %d", client->getPid(), client->getSocket());
 }

 class SocketLogWriter : public LogWriter {
   public:
     SocketLogWriter(LogReader* reader, SocketClient* client, bool privileged)
         : LogWriter(client->getUid(), privileged), reader_(reader), client_(client) {}

     bool Write(const logger_entry& entry, const char* msg) override {
         struct iovec iovec[2];
         iovec[0].iov_base = const_cast<logger_entry*>(&entry);
         iovec[0].iov_len = entry.hdr_size;
         iovec[1].iov_base = const_cast<char*>(msg);
         iovec[1].iov_len = entry.len;

         return client_->sendDatav(iovec, 1 + (entry.len != 0)) == 0;
     }

     void Release() override {
         reader_->release(client_);
         client_->decRef();
     }

     void Shutdown() override { shutdown(client_->getSocket(), SHUT_RDWR); }

     std::string name() const override { return SocketClientToName(client_); }

   private:
     LogReader* reader_;
     SocketClient* client_;
 };

 LogReader::LogReader(LogBuffer* logbuf, LogReaderList* reader_list)
     : SocketListener(getLogSocket(), true), log_buffer_(logbuf), reader_list_(reader_list) {}

 // Note returning false will release the SocketClient instance.
 bool LogReader::onDataAvailable(SocketClient* cli) {
     static bool name_set;
     if (!name_set) {
         prctl(PR_SET_NAME, "logd.reader");
         name_set = true;
     }

     char buffer[255];

     int len = read(cli->getSocket(), buffer, sizeof(buffer) - 1);
     if (len <= 0) {
         DoSocketDelete(cli);
         return false;
     }
     buffer[len] = '\0';

     // Clients are only allowed to send one command, disconnect them if they send another.
     if (DoSocketDelete(cli)) {
         return false;
     }

     unsigned long tail = 0;
     static const char _tail[] = " tail=";
     char* cp = strstr(buffer, _tail);
     if (cp) {
         tail = atol(cp + sizeof(_tail) - 1);
     }

     log_time start(log_time::EPOCH);
     static const char _start[] = " start=";
     cp = strstr(buffer, _start);
     if (cp) {
         // Parse errors will result in current time
         start.strptime(cp + sizeof(_start) - 1, "%s.%q");
     }

     std::chrono::steady_clock::time_point deadline = {};
     static const char _timeout[] = " timeout=";
     cp = strstr(buffer, _timeout);
     if (cp) {
         long timeout_seconds = atol(cp + sizeof(_timeout) - 1);
         deadline = std::chrono::steady_clock::now() + std::chrono::seconds(timeout_seconds);
     }

     unsigned int logMask = -1;
     static const char _logIds[] = " lids=";
     cp = strstr(buffer, _logIds);
     if (cp) {
         logMask = 0;
         cp += sizeof(_logIds) - 1;
         while (*cp != '\0') {
             int val = 0;
             while (isdigit(*cp)) {
                 val = val * 10 + *cp - '0';
                 ++cp;
             }
             logMask |= 1 << val;
             if (*cp != ',') {
                 break;
             }
             ++cp;
         }
     }

     pid_t pid = 0;
     static const char _pid[] = " pid=";
     cp = strstr(buffer, _pid);
     if (cp) {
         pid = atol(cp + sizeof(_pid) - 1);
     }

     bool nonBlock = false;
     if (!fastcmp<strncmp>(buffer, "dumpAndClose", 12)) {
         // Allow writer to get some cycles, and wait for pending notifications
         sched_yield();
         logd_lock.lock();
         logd_lock.unlock();
         sched_yield();
         nonBlock = true;
     }

     bool privileged = clientHasLogCredentials(cli);
     bool can_read_security = CanReadSecurityLogs(cli);
     if (!can_read_security) {
         logMask &= ~(1 << LOG_ID_SECURITY);
     }

     std::unique_ptr<LogWriter> socket_log_writer(new SocketLogWriter(this, cli, privileged));

     uint64_t sequence = 1;
     // Convert realtime to sequence number
     if (start != log_time::EPOCH) {
         bool start_time_set = false;
         uint64_t last = sequence;
         auto log_find_start = [pid, start, &sequence, &start_time_set, &last](
                                       log_id_t, pid_t element_pid, uint64_t element_sequence,
                                       log_time element_realtime) -> FilterResult {
             if (pid && pid != element_pid) {
                 return FilterResult::kSkip;
             }
             if (start == element_realtime) {
                 sequence = element_sequence;
                 start_time_set = true;
                 return FilterResult::kStop;
             } else {
                 if (start < element_realtime) {
                     sequence = last;
                     start_time_set = true;
                     return FilterResult::kStop;
                 }
                 last = element_sequence;
             }
             return FilterResult::kSkip;
         };
         auto lock = std::lock_guard{logd_lock};
         auto flush_to_state = log_buffer_->CreateFlushToState(sequence, logMask);
         log_buffer_->FlushTo(socket_log_writer.get(), *flush_to_state, log_find_start);

         if (!start_time_set) {
             if (nonBlock) {
                 return false;
             }
             sequence = log_buffer_->sequence();
         }
     }

     LOG(INFO) << android::base::StringPrintf(
             "logdr: UID=%d GID=%d PID=%d %c tail=%lu logMask=%x pid=%d "
             "start=%" PRIu64 "ns deadline=%" PRIi64 "ns",
             cli->getUid(), cli->getGid(), cli->getPid(), nonBlock ? 'n' : 'b', tail, logMask,
             (int)pid, start.nsec(), static_cast<int64_t>(deadline.time_since_epoch().count()));

     if (start == log_time::EPOCH) {
         deadline = {};
     }

     auto lock = std::lock_guard{logd_lock};
     auto entry = std::make_unique<LogReaderThread>(log_buffer_, reader_list_,
                                                    std::move(socket_log_writer), nonBlock, tail,
                                                    logMask, pid, start, sequence, deadline);
     // release client and entry reference counts once done
     cli->incRef();
     reader_list_->reader_threads().emplace_front(std::move(entry));

     // Set acceptable upper limit to wait for slow reader processing b/27242723
     struct timeval t = { LOGD_SNDTIMEO, 0 };
     setsockopt(cli->getSocket(), SOL_SOCKET, SO_SNDTIMEO, (const char*)&t,
                sizeof(t));

     return true;
 }

 bool LogReader::DoSocketDelete(SocketClient* cli) {
     auto cli_name = SocketClientToName(cli);
     auto lock = std::lock_guard{logd_lock};
     for (const auto& reader : reader_list_->reader_threads()) {
         if (reader->name() == cli_name) {
             reader->Release();
             return true;
         }
     }
     return false;
 }

 int LogReader::getLogSocket() {
     static const char socketName[] = "logdr";
     int sock = android_get_control_socket(socketName);

     if (sock < 0) {
         sock = socket_local_server(
             socketName, ANDROID_SOCKET_NAMESPACE_RESERVED, SOCK_SEQPACKET);
     }

     return sock;
 }
	/*
	* Copyright (C) 2012-2013 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 <ctype.h>
	#include <inttypes.h>
	#include <poll.h>
	#include <sched.h>
	#include <sys/prctl.h>
	#include <sys/socket.h>
	#include <sys/types.h>

	#include <chrono>

	#include <android-base/logging.h>
	#include <android-base/stringprintf.h>
	#include <cutils/sockets.h>
	#include <private/android_filesystem_config.h>
	#include <private/android_logger.h>

	#include "LogBuffer.h"
	#include "LogBufferElement.h"
	#include "LogPermissions.h"
	#include "LogReader.h"
	#include "LogUtils.h"
	#include "LogWriter.h"

	static bool CanReadSecurityLogs(SocketClient* client) {
	return client->getUid() == AID_SYSTEM \|\| client->getGid() == AID_SYSTEM;
	}

	static std::string SocketClientToName(SocketClient* client) {
	return android::base::StringPrintf("pid %d, fd %d", client->getPid(), client->getSocket());
	}

	class SocketLogWriter : public LogWriter {
	public:
	SocketLogWriter(LogReader* reader, SocketClient* client, bool privileged)
	: LogWriter(client->getUid(), privileged), reader_(reader), client_(client) {}

	bool Write(const logger_entry& entry, const char* msg) override {
	struct iovec iovec[2];
	iovec[0].iov_base = const_cast<logger_entry*>(&entry);
	iovec[0].iov_len = entry.hdr_size;
	iovec[1].iov_base = const_cast<char*>(msg);
	iovec[1].iov_len = entry.len;

	return client_->sendDatav(iovec, 1 + (entry.len != 0)) == 0;
	}

	void Release() override {
	reader_->release(client_);
	client_->decRef();
	}

	void Shutdown() override { shutdown(client_->getSocket(), SHUT_RDWR); }

	std::string name() const override { return SocketClientToName(client_); }

	private:
	LogReader* reader_;
	SocketClient* client_;
	};

	LogReader::LogReader(LogBuffer* logbuf, LogReaderList* reader_list)
	: SocketListener(getLogSocket(), true), log_buffer_(logbuf), reader_list_(reader_list) {}

	// Note returning false will release the SocketClient instance.
	bool LogReader::onDataAvailable(SocketClient* cli) {
	static bool name_set;
	if (!name_set) {
	prctl(PR_SET_NAME, "logd.reader");
	name_set = true;
	}

	char buffer[255];

	int len = read(cli->getSocket(), buffer, sizeof(buffer) - 1);
	if (len <= 0) {
	DoSocketDelete(cli);
	return false;
	}
	buffer[len] = '\0';

	// Clients are only allowed to send one command, disconnect them if they send another.
	if (DoSocketDelete(cli)) {
	return false;
	}

	unsigned long tail = 0;
	static const char _tail[] = " tail=";
	char* cp = strstr(buffer, _tail);
	if (cp) {
	tail = atol(cp + sizeof(_tail) - 1);
	}

	log_time start(log_time::EPOCH);
	static const char _start[] = " start=";
	cp = strstr(buffer, _start);
	if (cp) {
	// Parse errors will result in current time
	start.strptime(cp + sizeof(_start) - 1, "%s.%q");
	}

	std::chrono::steady_clock::time_point deadline = {};
	static const char _timeout[] = " timeout=";
	cp = strstr(buffer, _timeout);
	if (cp) {
	long timeout_seconds = atol(cp + sizeof(_timeout) - 1);
	deadline = std::chrono::steady_clock::now() + std::chrono::seconds(timeout_seconds);
	}

	unsigned int logMask = -1;
	static const char _logIds[] = " lids=";
	cp = strstr(buffer, _logIds);
	if (cp) {
	logMask = 0;
	cp += sizeof(_logIds) - 1;
	while (*cp != '\0') {
	int val = 0;
	while (isdigit(*cp)) {
	val = val * 10 + *cp - '0';
	++cp;
	}
	logMask \|= 1 << val;
	if (*cp != ',') {
	break;
	}
	++cp;
	}
	}

	pid_t pid = 0;
	static const char _pid[] = " pid=";
	cp = strstr(buffer, _pid);
	if (cp) {
	pid = atol(cp + sizeof(_pid) - 1);
	}

	bool nonBlock = false;
	if (!fastcmp<strncmp>(buffer, "dumpAndClose", 12)) {
	// Allow writer to get some cycles, and wait for pending notifications
	sched_yield();
	logd_lock.lock();
	logd_lock.unlock();
	sched_yield();
	nonBlock = true;
	}

	bool privileged = clientHasLogCredentials(cli);
	bool can_read_security = CanReadSecurityLogs(cli);
	if (!can_read_security) {
	logMask &= ~(1 << LOG_ID_SECURITY);
	}

	std::unique_ptr<LogWriter> socket_log_writer(new SocketLogWriter(this, cli, privileged));

	uint64_t sequence = 1;
	// Convert realtime to sequence number
	if (start != log_time::EPOCH) {
	bool start_time_set = false;
	uint64_t last = sequence;
	auto log_find_start = [pid, start, &sequence, &start_time_set, &last](
	log_id_t, pid_t element_pid, uint64_t element_sequence,
	log_time element_realtime) -> FilterResult {
	if (pid && pid != element_pid) {
	return FilterResult::kSkip;
	}
	if (start == element_realtime) {
	sequence = element_sequence;
	start_time_set = true;
	return FilterResult::kStop;
	} else {
	if (start < element_realtime) {
	sequence = last;
	start_time_set = true;
	return FilterResult::kStop;
	}
	last = element_sequence;
	}
	return FilterResult::kSkip;
	};
	auto lock = std::lock_guard{logd_lock};
	auto flush_to_state = log_buffer_->CreateFlushToState(sequence, logMask);
	log_buffer_->FlushTo(socket_log_writer.get(), *flush_to_state, log_find_start);

	if (!start_time_set) {
	if (nonBlock) {
	return false;
	}
	sequence = log_buffer_->sequence();
	}
	}

	LOG(INFO) << android::base::StringPrintf(
	"logdr: UID=%d GID=%d PID=%d %c tail=%lu logMask=%x pid=%d "
	"start=%" PRIu64 "ns deadline=%" PRIi64 "ns",
	cli->getUid(), cli->getGid(), cli->getPid(), nonBlock ? 'n' : 'b', tail, logMask,
	(int)pid, start.nsec(), static_cast<int64_t>(deadline.time_since_epoch().count()));

	if (start == log_time::EPOCH) {
	deadline = {};
	}

	auto lock = std::lock_guard{logd_lock};
	auto entry = std::make_unique<LogReaderThread>(log_buffer_, reader_list_,
	std::move(socket_log_writer), nonBlock, tail,
	logMask, pid, start, sequence, deadline);
	// release client and entry reference counts once done
	cli->incRef();
	reader_list_->reader_threads().emplace_front(std::move(entry));

	// Set acceptable upper limit to wait for slow reader processing b/27242723
	struct timeval t = { LOGD_SNDTIMEO, 0 };
	setsockopt(cli->getSocket(), SOL_SOCKET, SO_SNDTIMEO, (const char*)&t,
	sizeof(t));

	return true;
	}

	bool LogReader::DoSocketDelete(SocketClient* cli) {
	auto cli_name = SocketClientToName(cli);
	auto lock = std::lock_guard{logd_lock};
	for (const auto& reader : reader_list_->reader_threads()) {
	if (reader->name() == cli_name) {
	reader->Release();
	return true;
	}
	}
	return false;
	}

	int LogReader::getLogSocket() {
	static const char socketName[] = "logdr";
	int sock = android_get_control_socket(socketName);

	if (sock < 0) {
	sock = socket_local_server(
	socketName, ANDROID_SOCKET_NAMESPACE_RESERVED, SOCK_SEQPACKET);
	}

	return sock;
	}