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 <cutils/klog.h> 18 19 #include <errno.h> 20 #include <fcntl.h> 21 #include <stdarg.h> 22 #include <stdio.h> 23 #include <stdlib.h> 24 #include <string.h> 25 #include <sys/stat.h> 26 #include <sys/types.h> 27 #include <unistd.h> 28 29 #include <cutils/android_get_control_file.h> 30 31 static int klog_level = KLOG_INFO_LEVEL; 32 33 void klog_set_level(int level) { 34 klog_level = level; 35 } 36 37 static int __open_klog(void) { 38 static const char kmsg_device[] = "/dev/kmsg"; 39 40 int ret = android_get_control_file(kmsg_device); 41 if (ret >= 0) return ret; 42 return TEMP_FAILURE_RETRY(open(kmsg_device, O_WRONLY | O_CLOEXEC)); 43 } 44 45 #define LOG_BUF_MAX 512 46 47 void klog_writev(int level, const struct iovec* iov, int iov_count) { 48 if (level > klog_level) return; 49 50 static int klog_fd = __open_klog(); 51 if (klog_fd == -1) return; 52 TEMP_FAILURE_RETRY(writev(klog_fd, iov, iov_count)); 53 } 54 55 void klog_write(int level, const char* fmt, ...) { 56 if (level > klog_level) return; 57 58 char buf[LOG_BUF_MAX]; 59 va_list ap; 60 va_start(ap, fmt); 61 vsnprintf(buf, sizeof(buf), fmt, ap); 62 va_end(ap); 63 64 buf[LOG_BUF_MAX - 1] = 0; 65 66 struct iovec iov[1]; 67 iov[0].iov_base = buf; 68 iov[0].iov_len = strlen(buf); 69 klog_writev(level, iov, 1); 70 } 71