platform_system_core/init/log.cpp
Elliott Hughes 171a829c39 Make klog_fd thread-safe and make klog_init a no-op.
I'll come back and remove klog_init when I've removed other calls to it.

Change-Id: Iad7fd26d853b4ddc54e9abd44516b6f138cbbfcb
Test: booted N9, looked at "adb shell dmesg" output.
2016-06-29 16:16:41 -07:00

88 lines
2.9 KiB
C++

/*
* Copyright (C) 2015 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 "log.h"
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <selinux/selinux.h>
static const int kLogSeverityToKLogLevel[] = {
KLOG_NOTICE_LEVEL, KLOG_DEBUG_LEVEL, KLOG_INFO_LEVEL,
KLOG_WARNING_LEVEL, KLOG_ERROR_LEVEL, KLOG_ERROR_LEVEL,
};
static_assert(arraysize(kLogSeverityToKLogLevel) == android::base::FATAL + 1,
"Mismatch in size of kLogSeverityToKLogLevel and values in LogSeverity");
static void KernelLogger(android::base::LogId, android::base::LogSeverity severity,
const char* tag, const char*, unsigned int, const char* msg) {
int level = kLogSeverityToKLogLevel[severity];
if (level > klog_get_level()) return;
// The kernel's printk buffer is only 1024 bytes.
// TODO: should we automatically break up long lines into multiple lines?
// Or we could log but with something like "..." at the end?
char buf[1024];
size_t size = snprintf(buf, sizeof(buf), "<%d>%s: %s\n", level, tag, msg);
if (size > sizeof(buf)) {
size = snprintf(buf, sizeof(buf), "<%d>%s: %zu-byte message too long for printk\n",
level, tag, size);
}
iovec iov[1];
iov[0].iov_base = buf;
iov[0].iov_len = size;
klog_writev(level, iov, 1);
}
void InitKernelLogging(char* argv[]) {
// Make stdin/stdout/stderr all point to /dev/null.
int fd = open("/sys/fs/selinux/null", O_RDWR);
if (fd == -1) {
int saved_errno = errno;
android::base::InitLogging(argv, &KernelLogger);
errno = saved_errno;
PLOG(FATAL) << "Couldn't open /sys/fs/selinux/null";
}
dup2(fd, 0);
dup2(fd, 1);
dup2(fd, 2);
if (fd > 2) close(fd);
android::base::InitLogging(argv, &KernelLogger);
klog_set_level(KLOG_NOTICE_LEVEL);
}
int selinux_klog_callback(int type, const char *fmt, ...) {
android::base::LogSeverity severity = android::base::ERROR;
if (type == SELINUX_WARNING) {
severity = android::base::WARNING;
} else if (type == SELINUX_INFO) {
severity = android::base::INFO;
}
char buf[1024];
va_list ap;
va_start(ap, fmt);
vsnprintf(buf, sizeof(buf), fmt, ap);
va_end(ap);
KernelLogger(android::base::MAIN, severity, "selinux", nullptr, 0, buf);
return 0;
}