• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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