platform_system_core/liblog/logger_lock.c

83 lines
1.9 KiB
C

/*
* Copyright (C) 2007-2016 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.
*/
/*
* Some OS specific dribs and drabs (locking etc).
*/
#if !defined(_WIN32)
#include <pthread.h>
#endif
#include <private/android_filesystem_config.h>
#include "logger.h"
LIBLOG_HIDDEN uid_t __android_log_uid()
{
#if defined(_WIN32)
return AID_SYSTEM;
#else
static uid_t last_uid = AID_ROOT; /* logd *always* starts up as AID_ROOT */
if (last_uid == AID_ROOT) { /* have we called to get the UID yet? */
last_uid = getuid();
}
return last_uid;
#endif
}
LIBLOG_HIDDEN pid_t __android_log_pid()
{
static pid_t last_pid = (pid_t) -1;
if (last_pid == (pid_t) -1) {
last_pid = getpid();
}
return last_pid;
}
#if !defined(_WIN32)
static pthread_mutex_t log_init_lock = PTHREAD_MUTEX_INITIALIZER;
#endif
LIBLOG_HIDDEN void __android_log_lock()
{
#if !defined(_WIN32)
/*
* If we trigger a signal handler in the middle of locked activity and the
* signal handler logs a message, we could get into a deadlock state.
*/
pthread_mutex_lock(&log_init_lock);
#endif
}
LIBLOG_HIDDEN int __android_log_trylock()
{
#if !defined(_WIN32)
return pthread_mutex_trylock(&log_init_lock);
#else
return 0;
#endif
}
LIBLOG_HIDDEN void __android_log_unlock()
{
#if !defined(_WIN32)
pthread_mutex_unlock(&log_init_lock);
#endif
}