1/* 2 * Copyright (C) 2008 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include <errno.h> 18#include <fcntl.h> 19#include <stdarg.h> 20#include <stdio.h> 21#include <stdlib.h> 22#include <string.h> 23#include <sys/stat.h> 24#include <sys/types.h> 25#include <unistd.h> 26 27#include <cutils/klog.h> 28 29static int klog_fd = -1; 30static int klog_level = KLOG_DEFAULT_LEVEL; 31 32int klog_get_level(void) { 33 return klog_level; 34} 35 36void klog_set_level(int level) { 37 klog_level = level; 38} 39 40void klog_init(void) { 41 if (klog_fd >= 0) return; /* Already initialized */ 42 43 klog_fd = open("/dev/kmsg", O_WRONLY | O_CLOEXEC); 44 if (klog_fd >= 0) { 45 return; 46 } 47 48 static const char* name = "/dev/__kmsg__"; 49 if (mknod(name, S_IFCHR | 0600, (1 << 8) | 11) == 0) { 50 klog_fd = open(name, O_WRONLY | O_CLOEXEC); 51 unlink(name); 52 } 53} 54 55#define LOG_BUF_MAX 512 56 57void klog_writev(int level, const struct iovec* iov, int iov_count) { 58 if (level > klog_level) return; 59 if (klog_fd < 0) klog_init(); 60 if (klog_fd < 0) return; 61 TEMP_FAILURE_RETRY(writev(klog_fd, iov, iov_count)); 62} 63 64void klog_write(int level, const char* fmt, ...) { 65 if (level > klog_level) return; 66 char buf[LOG_BUF_MAX]; 67 va_list ap; 68 va_start(ap, fmt); 69 vsnprintf(buf, sizeof(buf), fmt, ap); 70 va_end(ap); 71 72 buf[LOG_BUF_MAX - 1] = 0; 73 74 struct iovec iov[1]; 75 iov[0].iov_base = buf; 76 iov[0].iov_len = strlen(buf); 77 klog_writev(level, iov, 1); 78} 79