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         const char *log_level_str;
  72         int syslog_level;
  73
  74         switch (log_level) {
  75         case INFO:
  76                 log_level_str = "INFO:    ";
  77                 syslog_level = LOG_INFO;
  78                 break;
  79         case WARNING:
  80                 log_level_str = "WARNING: ";
  81                 syslog_level = LOG_WARNING;
  82                 break;
  83         case ERROR:
  84                 log_level_str = "ERROR:   ";
  85                 syslog_level = LOG_ERR;
  86                 break;
  87         default:
  88                 assert(false);
  89         }
  90
  91         // Log to stderr if logging hasn't been set up yet. Note that this means
  92         // that such messages will come even if there are no “error_log” lines.
  93         if (!logging_started) {
  94                 fprintf(stderr, "%s%s\n", log_level_str, formatted_msg);
  95                 return;
  96         }
  97
  98         for (size_t i = 0; i < log_destinations.size(); ++i) {
  99                 if (log_destinations[i] == SYSLOG_FAKE_FILE) {
 100                         syslog(syslog_level, "%s", formatted_msg);
 101                 } else {
 102                         int err = fprintf(log_destinations[i], "%s%s\n", log_level_str, formatted_msg);
 103                         if (err < 0) {
 104                                 perror("fprintf");
 105                         }
 106                         if (log_destinations[i] != stderr) {
 107                                 fflush(log_destinations[i]);
 108                         }
 109                 }
 110         }
 111 }
 112
 113 void log_perror(const char *msg)
 114 {
 115         char errbuf[4096];
 116         log(ERROR, "%s: %s", msg, strerror_r(errno, errbuf, sizeof(errbuf)));
 117 }