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 #include <unistd.h>
22
23 #include <async_safe/log.h>
24
25 static const char* syslog_log_tag = nullptr;
26 static int syslog_priority_mask = 0xff;
27 static int syslog_options = 0;
28
closelog()29 void closelog() {
30 syslog_log_tag = nullptr;
31 syslog_options = 0;
32 }
33
openlog(const char * log_tag,int options,int)34 void openlog(const char* log_tag, int options, int /*facility*/) {
35 syslog_log_tag = log_tag;
36 syslog_options = options;
37 }
38
setlogmask(int new_mask)39 int setlogmask(int new_mask) {
40 int old_mask = syslog_priority_mask;
41 // 0 is used to query the current mask.
42 if (new_mask != 0) {
43 syslog_priority_mask = new_mask;
44 }
45 return old_mask;
46 }
47
syslog(int priority,const char * fmt,...)48 void syslog(int priority, const char* fmt, ...) {
49 va_list args;
50 va_start(args, fmt);
51 vsyslog(priority, fmt, args);
52 va_end(args);
53 }
54
vsyslog(int priority,const char * fmt,va_list args)55 void vsyslog(int priority, const char* fmt, va_list args) {
56 // Check whether we're supposed to be logging messages of this priority.
57 if ((syslog_priority_mask & LOG_MASK(LOG_PRI(priority))) == 0) {
58 return;
59 }
60
61 // What's our log tag?
62 const char* log_tag = syslog_log_tag;
63 if (log_tag == nullptr) {
64 log_tag = getprogname();
65 }
66
67 // What's our Android log priority?
68 priority &= LOG_PRIMASK;
69 int android_log_priority;
70 if (priority <= LOG_ERR) {
71 android_log_priority = ANDROID_LOG_ERROR;
72 } else if (priority == LOG_WARNING) {
73 android_log_priority = ANDROID_LOG_WARN;
74 } else if (priority <= LOG_INFO) {
75 android_log_priority = ANDROID_LOG_INFO;
76 } else {
77 android_log_priority = ANDROID_LOG_DEBUG;
78 }
79
80 // We can't let async_safe_format_log do the formatting because it doesn't
81 // support all the printf functionality.
82 char log_line[1024];
83 int n = vsnprintf(log_line, sizeof(log_line), fmt, args);
84 if (n < 0) return;
85
86 async_safe_format_log(android_log_priority, log_tag, "%s", log_line);
87 if ((syslog_options & LOG_PERROR) != 0) {
88 bool have_newline =
89 (n > 0 && n < static_cast<int>(sizeof(log_line)) && log_line[n - 1] == '\n');
90 dprintf(STDERR_FILENO, "%s: %s%s", log_tag, log_line, have_newline ? "" : "\n");
91 }
92 }
93