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