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
29 static int klog_fd = -1;
30 static int klog_level = KLOG_DEFAULT_LEVEL;
31
klog_get_level(void)32 int klog_get_level(void) {
33 return klog_level;
34 }
35
klog_set_level(int level)36 void klog_set_level(int level) {
37 klog_level = level;
38 }
39
klog_init(void)40 void 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
klog_writev(int level,const struct iovec * iov,int iov_count)57 void 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
klog_write(int level,const char * fmt,...)64 void 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