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
27static 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
50void 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
57int 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