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

   1 #include <assert.h>
   2 #include <errno.h>
   3 #include <stdarg.h>
   4 #include <stddef.h>
   5 #include <stdio.h>
   6 #include <string.h>
   7 #include <syslog.h>
   8 #include <time.h>
   9 #include <string>
  10 #include <vector>
  11
  12 #include "log.h"
  13
  14 using namespace std;
  15
  16 // Yes, it's a bit ugly.
  17 #define SYSLOG_FAKE_FILE (static_cast<FILE *>(NULL))
  18
  19 bool logging_started = false;
  20 std::vector<FILE *> log_destinations;
  21
  22 void add_log_destination_file(const std::string &filename)
  23 {
  24         FILE *fp = fopen(filename.c_str(), "a");
  25         if (fp == NULL) {
  26                 perror(filename.c_str());
  27                 return;
  28         }
  29
  30         log_destinations.push_back(fp);
  31 }
  32
  33 void add_log_destination_console()
  34 {
  35         log_destinations.push_back(stderr);
  36 }
  37
  38 void add_log_destination_syslog()
  39 {
  40         openlog("cubemap", LOG_PID, LOG_DAEMON);
  41         log_destinations.push_back(SYSLOG_FAKE_FILE);
  42 }
  43
  44 void start_logging()
  45 {
  46         logging_started = true;
  47 }
  48
  49 void shut_down_logging()
  50 {
  51         for (size_t i = 0; i < log_destinations.size(); ++i) {
  52                 if (log_destinations[i] == SYSLOG_FAKE_FILE) {
  53                         closelog();
  54                 } else if (log_destinations[i] != stderr) {
  55                         if (fclose(log_destinations[i]) != 0) {
  56                                 perror("fclose");
  57                         }
  58                 }
  59         }
  60         log_destinations.clear();
  61         logging_started = false;
  62 }
  63
  64 void log(LogLevel log_level, const char *fmt, ...)
  65 {
  66         char formatted_msg[4096];
  67         va_list ap;
  68         va_start(ap, fmt);
  69         vsnprintf(formatted_msg, sizeof(formatted_msg), fmt, ap);
  70         va_end(ap);
  71
  72         time_t now = time(NULL);
  73         struct tm lt;
  74         struct tm *ltime = localtime_r(&now, &lt);
  75         char timestamp[1024];
  76         if (ltime == NULL) {
  77                 strcpy(timestamp, "???");
  78         } else {
  79                 strftime(timestamp, sizeof(timestamp), "%a, %d %b %Y %T %z", ltime);
  80         }
  81
  82         const char *log_level_str;
  83         int syslog_level;
  84
  85         switch (log_level) {
  86         case INFO:
  87                 log_level_str = "INFO:    ";
  88                 syslog_level = LOG_INFO;
  89                 break;
  90         case WARNING:
  91                 log_level_str = "WARNING: ";
  92                 syslog_level = LOG_WARNING;
  93                 break;
  94         case ERROR:
  95                 log_level_str = "ERROR:   ";
  96                 syslog_level = LOG_ERR;
  97                 break;
  98         default:
  99                 assert(false);
 100         }
 101
 102         // Log to stderr if logging hasn't been set up yet. Note that this means
 103         // that such messages will come even if there are no “error_log” lines.
 104         if (!logging_started) {
 105                 fprintf(stderr, "[%s] %s%s\n", timestamp, log_level_str, formatted_msg);
 106                 return;
 107         }
 108
 109         for (size_t i = 0; i < log_destinations.size(); ++i) {
 110                 if (log_destinations[i] == SYSLOG_FAKE_FILE) {
 111                         syslog(syslog_level, "%s", formatted_msg);
 112                 } else {
 113                         int err = fprintf(log_destinations[i], "[%s] %s%s\n", timestamp, log_level_str, formatted_msg);
 114                         if (err < 0) {
 115                                 perror("fprintf");
 116                         }
 117                         if (log_destinations[i] != stderr) {
 118                                 fflush(log_destinations[i]);
 119                         }
 120                 }
 121         }
 122 }
 123
 124 void log_perror(const char *msg)
 125 {
 126         char errbuf[4096];
 127         log(ERROR, "%s: %s", msg, strerror_r(errno, errbuf, sizeof(errbuf)));
 128 }