1 /*
2  * Copyright (C) 2015 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 "log.h"
18 
19 #include <stdlib.h>
20 #include <string.h>
21 #include <sys/uio.h>
22 
23 #include <selinux/selinux.h>
24 
25 #include <android-base/stringprintf.h>
26 
init_klog_vwrite(int level,const char * fmt,va_list ap)27 static void init_klog_vwrite(int level, const char* fmt, va_list ap) {
28     static const char* tag = basename(getprogname());
29 
30     if (level > klog_get_level()) return;
31 
32     // The kernel's printk buffer is only 1024 bytes.
33     // TODO: should we automatically break up long lines into multiple lines?
34     // Or we could log but with something like "..." at the end?
35     char buf[1024];
36     size_t prefix_size = snprintf(buf, sizeof(buf), "<%d>%s: ", level, tag);
37     size_t msg_size = vsnprintf(buf + prefix_size, sizeof(buf) - prefix_size, fmt, ap);
38     if (msg_size >= sizeof(buf) - prefix_size) {
39         msg_size = snprintf(buf + prefix_size, sizeof(buf) - prefix_size,
40                             "(%zu-byte message too long for printk)\n", msg_size);
41     }
42 
43     iovec iov[1];
44     iov[0].iov_base = buf;
45     iov[0].iov_len = prefix_size + msg_size;
46 
47     klog_writev(level, iov, 1);
48 }
49 
init_klog_write(int level,const char * fmt,...)50 void init_klog_write(int level, const char* fmt, ...) {
51     va_list ap;
52     va_start(ap, fmt);
53     init_klog_vwrite(level, fmt, ap);
54     va_end(ap);
55 }
56 
selinux_klog_callback(int type,const char * fmt,...)57 int selinux_klog_callback(int type, const char *fmt, ...) {
58     int level = KLOG_ERROR_LEVEL;
59     if (type == SELINUX_WARNING) {
60         level = KLOG_WARNING_LEVEL;
61     } else if (type == SELINUX_INFO) {
62         level = KLOG_INFO_LEVEL;
63     }
64     va_list ap;
65     va_start(ap, fmt);
66     init_klog_vwrite(level, fmt, ap);
67     va_end(ap);
68     return 0;
69 }
70