1 /*
2 * Copyright (C) 2014 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 <stdlib.h>
19 #include <string.h>
20 #include <syslog.h>
21
22 #include "private/libc_logging.h"
23
24 static const char* syslog_log_tag = NULL;
25 static int syslog_priority_mask = 0xff;
26
closelog()27 void closelog() {
28 syslog_log_tag = NULL;
29 }
30
openlog(const char * log_tag,int,int)31 void openlog(const char* log_tag, int /*options*/, int /*facility*/) {
32 syslog_log_tag = log_tag;
33 }
34
setlogmask(int new_mask)35 int setlogmask(int new_mask) {
36 int old_mask = syslog_priority_mask;
37 // 0 is used to query the current mask.
38 if (new_mask != 0) {
39 syslog_priority_mask = new_mask;
40 }
41 return old_mask;
42 }
43
syslog(int priority,const char * fmt,...)44 void syslog(int priority, const char* fmt, ...) {
45 va_list args;
46 va_start(args, fmt);
47 vsyslog(priority, fmt, args);
48 va_end(args);
49 }
50
vsyslog(int priority,const char * fmt,va_list args)51 void vsyslog(int priority, const char* fmt, va_list args) {
52 int caller_errno = errno;
53
54 // Check whether we're supposed to be logging messages of this priority.
55 if ((syslog_priority_mask & LOG_MASK(LOG_PRI(priority))) == 0) {
56 return;
57 }
58
59 // What's our log tag?
60 const char* log_tag = syslog_log_tag;
61 if (log_tag == NULL) {
62 log_tag = getprogname();
63 }
64
65 // What's our Android log priority?
66 priority &= LOG_PRIMASK;
67 int android_log_priority;
68 if (priority <= LOG_ERR) {
69 android_log_priority = ANDROID_LOG_ERROR;
70 } else if (priority == LOG_WARNING) {
71 android_log_priority = ANDROID_LOG_WARN;
72 } else if (priority <= LOG_INFO) {
73 android_log_priority = ANDROID_LOG_INFO;
74 } else {
75 android_log_priority = ANDROID_LOG_DEBUG;
76 }
77
78 // glibc's printf family support %m directly, but our BSD-based one doesn't.
79 // If the format string seems to contain "%m", rewrite it.
80 const char* log_fmt = fmt;
81 if (strstr(fmt, "%m") != NULL) {
82 size_t dst_len = 1024;
83 char* dst = reinterpret_cast<char*>(malloc(dst_len));
84 log_fmt = dst;
85
86 const char* src = fmt;
87 for (; dst_len > 0 && *src != '\0'; ++src) {
88 if (*src == '%' && *(src + 1) == 'm') {
89 // Expand %m.
90 size_t n = strlcpy(dst, strerror(caller_errno), dst_len);
91 if (n >= dst_len) {
92 n = dst_len;
93 }
94 dst += n;
95 dst_len -= n;
96 ++src;
97 } else if (*src == '%' && *(src + 1) == '%') {
98 // We need to copy pairs of '%'s so the %m test works.
99 if (dst_len <= 2) {
100 break;
101 }
102 *dst++ = '%'; --dst_len;
103 *dst++ = '%'; --dst_len;
104 ++src;
105 } else {
106 *dst++ = *src; --dst_len;
107 }
108 }
109 *dst = '\0';
110 }
111
112 // We can't let __libc_format_log do the formatting because it doesn't support
113 // all the printf functionality.
114 char log_line[1024];
115 vsnprintf(log_line, sizeof(log_line), log_fmt, args);
116
117 if (log_fmt != fmt) {
118 free(const_cast<char*>(log_fmt));
119 }
120
121 __libc_format_log(android_log_priority, log_tag, "%s", log_line);
122 }
123