platform_system_core/logd/FlushCommand.cpp
Tom Cherry 4f22786cc9 logd: rework logic for LogTimeEntry
LogTimeEntry's lifecycle is spread out in various locations.  It
further seems incomplete as there is logic that assumes that its
associated thread can exit while the underlying LogTimeEntry remains
valid, however it doesn't appear that that is actually a supported
situation.

This change simplifies this logic to have only one valid state for a
LogTimeEntry: it must have its thread running and be present in
LastLogTimes.  A LogTimeEntry will never be placed into LastLogTimes
unless its thread is running and its thread will remove its associated
LogTimeEntry from LastLogTimes before it has exited.

This admittedly breaks situations where a blocking socket gets issued
multiple commands with different pid filters, tail lines, etc,
however, I'm reasonably sure that these situations were already
broken.  A check is added to close the socket in this case.

Test: multiple logcat instances work, logd.reader.per's are cleaned up
Change-Id: Ibe8651e7d530c5e9a8d6ce3150cd247982887cbe
2018-10-12 18:28:59 -07:00

85 lines
2.8 KiB
C++

/*
* Copyright (C) 2012-2014 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 <stdlib.h>
#include <private/android_filesystem_config.h>
#include "FlushCommand.h"
#include "LogBuffer.h"
#include "LogBufferElement.h"
#include "LogCommand.h"
#include "LogReader.h"
#include "LogTimes.h"
#include "LogUtils.h"
// runSocketCommand is called once for every open client on the
// log reader socket. Here we manage and associated the reader
// client tracking and log region locks LastLogTimes list of
// LogTimeEntrys, and spawn a transitory per-client thread to
// work at filing data to the socket.
//
// global LogTimeEntry::wrlock() is used to protect access,
// reference counts are used to ensure that individual
// LogTimeEntry lifetime is managed when not protected.
void FlushCommand::runSocketCommand(SocketClient* client) {
LogTimeEntry* entry = nullptr;
LastLogTimes& times = mReader.logbuf().mTimes;
LogTimeEntry::wrlock();
LastLogTimes::iterator it = times.begin();
while (it != times.end()) {
entry = it->get();
if (entry->mClient == client) {
if (!entry->isWatchingMultiple(mLogMask)) {
LogTimeEntry::unlock();
return;
}
if (entry->mTimeout.tv_sec || entry->mTimeout.tv_nsec) {
if (mReader.logbuf().isMonotonic()) {
LogTimeEntry::unlock();
return;
}
// If the user changes the time in a gross manner that
// invalidates the timeout, fall through and trigger.
log_time now(CLOCK_REALTIME);
if (((entry->mEnd + entry->mTimeout) > now) &&
(now > entry->mEnd)) {
LogTimeEntry::unlock();
return;
}
}
entry->triggerReader_Locked();
LogTimeEntry::unlock();
return;
}
it++;
}
LogTimeEntry::unlock();
}
bool FlushCommand::hasReadLogs(SocketClient* client) {
return clientHasLogCredentials(client);
}
static bool clientHasSecurityCredentials(SocketClient* client) {
return (client->getUid() == AID_SYSTEM) || (client->getGid() == AID_SYSTEM);
}
bool FlushCommand::hasSecurityLogs(SocketClient* client) {
return clientHasSecurityCredentials(client);
}