git.sesse.net Git - cubemap/blob - log.cpp

   1 #include "log.h"
   2
   3 #include <stdio.h>
   4 #include <string.h>
   5 #include <stdarg.h>
   6 #include <syslog.h>
   7 #include <assert.h>
   8 #include <errno.h>
   9 #include <string>
  10 #include <vector>
  11
  12 using namespace std;
  13
  14 // Yes, it's a bit ugly.
  15 #define SYSLOG_FAKE_FILE (static_cast<FILE *>(NULL))
  16
  17 bool logging_started = false;
  18 std::vector<FILE *> log_destinations;
  19
  20 void add_log_destination_file(const std::string &filename)
  21 {
  22         FILE *fp = fopen(filename.c_str(), "a");
  23         if (fp == NULL) {
  24                 perror(filename.c_str());
  25                 return;
  26         }
  27
  28         log_destinations.push_back(fp);
  29 }
  30
  31 void add_log_destination_console()
  32 {
  33         log_destinations.push_back(stderr);
  34 }
  35
  36 void add_log_destination_syslog()
  37 {
  38         openlog("cubemap", LOG_PID, LOG_DAEMON);
  39         log_destinations.push_back(SYSLOG_FAKE_FILE);
  40 }
  41
  42 void start_logging()
  43 {
  44         logging_started = true;
  45 }
  46
  47 void shut_down_logging()
  48 {
  49         for (size_t i = 0; i < log_destinations.size(); ++i) {
  50                 if (log_destinations[i] == SYSLOG_FAKE_FILE) {
  51                         closelog();
  52                 } else if (log_destinations[i] != stderr) {
  53                         if (fclose(log_destinations[i]) != 0) {
  54                                 perror("fclose");
  55                         }
  56                 }
  57         }
  58         log_destinations.clear();
  59         logging_started = false;
  60 }
  61
  62 void log(LogLevel log_level, const char *fmt, ...)
  63 {
  64         char formatted_msg[4096];
  65         va_list ap;
  66         va_start(ap, fmt);
  67         vsnprintf(formatted_msg, sizeof(formatted_msg), fmt, ap);
  68         va_end(ap);
  69
  70         const char *log_level_str;
  71         int syslog_level;
  72
  73         switch (log_level) {
  74         case INFO:
  75                 log_level_str = "INFO:    ";
  76                 syslog_level = LOG_INFO;
  77                 break;
  78         case WARNING:
  79                 log_level_str = "WARNING: ";
  80                 syslog_level = LOG_WARNING;
  81                 break;
  82         case ERROR:
  83                 log_level_str = "ERROR:   ";
  84                 syslog_level = LOG_ERR;
  85                 break;
  86         default:
  87                 assert(false);
  88         }
  89
  90         // Log to stderr if logging hasn't been set up yet. Note that this means
  91         // that such messages will come even if there are no “error_log” lines.
  92         if (!logging_started) {
  93                 fprintf(stderr, "%s%s\n", log_level_str, formatted_msg);
  94                 return;
  95         }
  96
  97         for (size_t i = 0; i < log_destinations.size(); ++i) {
  98                 if (log_destinations[i] == SYSLOG_FAKE_FILE) {
  99                         syslog(syslog_level, "%s", formatted_msg);
 100                 } else {
 101                         int err = fprintf(log_destinations[i], "%s%s\n", log_level_str, formatted_msg);
 102                         if (err < 0) {
 103                                 perror("fprintf");
 104                         }
 105                         if (log_destinations[i] != stderr) {
 106                                 fflush(log_destinations[i]);
 107                         }
 108                 }
 109         }
 110 }
 111
 112 void log_perror(const char *msg)
 113 {
 114         char errbuf[4096];
 115         log(ERROR, "%s: %s", msg, strerror_r(errno, errbuf, sizeof(errbuf)));
 116 }