/*
* 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 <sys/prctl.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <cutils/sockets.h>
#include <private/android_logger.h>
#include "FlushCommand.h"
#include "LogBuffer.h"
#include "LogBufferElement.h"
#include "LogReader.h"
#include "LogUtils.h"
LogReader::LogReader(LogBuffer* logbuf)
: SocketListener(getLogSocket(), true), mLogbuf(*logbuf) {
}
// When we are notified a new log entry is available, inform
// listening sockets who are watching this entry's log id.
void LogReader::notifyNewLog(log_mask_t logMask) {
FlushCommand command(*this, logMask);
runOnEachSocket(&command);
}
// 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.
LogTimeEntry::wrlock();
for (const auto& entry : mLogbuf.mTimes) {
if (entry->mClient == cli) {
entry->release_Locked();
LogTimeEntry::unlock();
return false;
}
}
LogTimeEntry::unlock();
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");
}
uint64_t timeout = 0;
static const char _timeout[] = " timeout=";
cp = strstr(buffer, _timeout);
if (cp) {
timeout = atol(cp + sizeof(_timeout) - 1) * NS_PER_SEC +
log_time(CLOCK_REALTIME).nsec();
}
unsigned int logMask = -1;
static const char _logIds[] = " lids=";
cp = strstr(buffer, _logIds);
if (cp) {
logMask = 0;
cp += sizeof(_logIds) - 1;
while (*cp && *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();
LogTimeEntry::wrlock();
LogTimeEntry::unlock();
sched_yield();
nonBlock = true;
}
log_time sequence = start;
//
// This somewhat expensive data validation operation is required
// for non-blocking, with timeout. The incoming timestamp must be
// in range of the list, if not, return immediately. This is
// used to prevent us from from getting stuck in timeout processing
// with an invalid time.
//
// Find if time is really present in the logs, monotonic or real, implicit
// conversion from monotonic or real as necessary to perform the check.
// Exit in the check loop ASAP as you find a transition from older to
// newer, but use the last entry found to ensure overlap.
//
if (nonBlock && (sequence != log_time::EPOCH) && timeout) {
class LogFindStart { // A lambda by another name
private:
const pid_t mPid;
const unsigned mLogMask;
bool mStartTimeSet;
log_time mStart;
log_time& mSequence;
log_time mLast;
bool mIsMonotonic;
public:
LogFindStart(pid_t pid, unsigned logMask, log_time& sequence,
bool isMonotonic)
: mPid(pid),
mLogMask(logMask),
mStartTimeSet(false),
mStart(sequence),
mSequence(sequence),
mLast(sequence),
mIsMonotonic(isMonotonic) {
}
static int callback(const LogBufferElement* element, void* obj) {
LogFindStart* me = reinterpret_cast<LogFindStart*>(obj);
if ((!me->mPid || (me->mPid == element->getPid())) &&
(me->mLogMask & (1 << element->getLogId()))) {
log_time real = element->getRealTime();
if (me->mStart == real) {
me->mSequence = real;
me->mStartTimeSet = true;
return -1;
} else if (!me->mIsMonotonic || android::isMonotonic(real)) {
if (me->mStart < real) {
me->mSequence = me->mLast;
me->mStartTimeSet = true;
return -1;
}
me->mLast = real;
} else {
me->mLast = real;
}
}
return false;
}
bool found() {
return mStartTimeSet;
}
} logFindStart(pid, logMask, sequence,
logbuf().isMonotonic() && android::isMonotonic(start));
logbuf().flushTo(cli, sequence, nullptr, FlushCommand::hasReadLogs(cli),
FlushCommand::hasSecurityLogs(cli),
logFindStart.callback, &logFindStart);
if (!logFindStart.found()) {
doSocketDelete(cli);
return false;
}
}
android::prdebug(
"logdr: UID=%d GID=%d PID=%d %c tail=%lu logMask=%x pid=%d "
"start=%" PRIu64 "ns timeout=%" PRIu64 "ns\n",
cli->getUid(), cli->getGid(), cli->getPid(), nonBlock ? 'n' : 'b', tail,
logMask, (int)pid, sequence.nsec(), timeout);
if (sequence == log_time::EPOCH) {
timeout = 0;
}
LogTimeEntry::wrlock();
auto entry = std::make_unique<LogTimeEntry>(
*this, cli, nonBlock, tail, logMask, pid, sequence, timeout);
if (!entry->startReader_Locked()) {
LogTimeEntry::unlock();
return false;
}
// release client and entry reference counts once done
cli->incRef();
mLogbuf.mTimes.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));
LogTimeEntry::unlock();
return true;
}
void LogReader::doSocketDelete(SocketClient* cli) {
LastLogTimes& times = mLogbuf.mTimes;
LogTimeEntry::wrlock();
LastLogTimes::iterator it = times.begin();
while (it != times.end()) {
LogTimeEntry* entry = it->get();
if (entry->mClient == cli) {
entry->release_Locked();
break;
}
it++;
}
LogTimeEntry::unlock();
}
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;
}