mdw@git.distorted.org.uk Git - disorder/blob - lib/log.c

   1 /*
   2  * This file is part of DisOrder.
   3  * Copyright (C) 2004-2008 Richard Kettlewell
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  18  * USA
  19  */
  20 /** @file lib/log.c @brief Errors and logging
  21  *
  22  * All messages are initially emitted by one of the four functions below.
  23  * debug() is generally invoked via D() so that mostly you just do a test
  24  * rather than a complete subroutine call.
  25  *
  26  * Messages are dispatched via @ref log_default.  This defaults to @ref
  27  * log_stderr.  daemonize() will turn off @ref log_stderr and use @ref
  28  * log_syslog instead.
  29  *
  30  * fatal() will call exitfn() with a nonzero status.  The default value is
  31  * exit(), but it should be set to _exit() anywhere but the 'main line' of the
  32  * program, to guarantee that exit() gets called at most once.
  33  */
  34
  35 #define NO_MEMORY_ALLOCATION
  36 /* because the memory allocation functions report errors */
  37
  38 #include <config.h>
  39
  40 #include <stdio.h>
  41 #include <stdlib.h>
  42 #include <string.h>
  43 #include <errno.h>
  44 #include <syslog.h>
  45 #include <sys/time.h>
  46
  47 #include "log.h"
  48 #include "disorder.h"
  49 #include "printf.h"
  50
  51 /** @brief Definition of a log output */
  52 struct log_output {
  53   /** @brief Function to call */
  54   void (*fn)(int pri, const char *msg, void *user);
  55   /** @brief User data */
  56   void *user;
  57 };
  58
  59 /** @brief Function to call on a fatal error
  60  *
  61  * This is normally @c exit() but in the presence of @c fork() it
  62  * sometimes gets set to @c _exit(). */
  63 void (*exitfn)(int) attribute((noreturn)) = exit;
  64
  65 /** @brief Debug flag */
  66 int debugging;
  67
  68 /** @brief Program name */
  69 const char *progname;
  70
  71 /** @brief Filename for debug messages */
  72 const char *debug_filename;
  73
  74 /** @brief Line number for debug messages */
  75 int debug_lineno;
  76
  77 /** @brief Pointer to chosen log output structure */
  78 struct log_output *log_default = &log_stderr;
  79
  80 /** @brief Filename to debug for */
  81 static const char *debug_only;
  82
  83 /** @brief Construct log line, encoding special characters
  84  *
  85  * We might be receiving things in any old encoding, or binary rubbish
  86  * in no encoding at all, so escape anything we don't like the look
  87  * of.  We limit the log message to a kilobyte.
  88  */
  89 static void format(char buffer[], size_t bufsize, const char *fmt, va_list ap) {
  90   char t[1024];
  91   const char *p;
  92   int ch;
  93   size_t n = 0;
  94
  95   if(byte_vsnprintf(t, sizeof t, fmt, ap) < 0) {
  96     strcpy(t, "[byte_vsnprintf failed: ");
  97     strncat(t, fmt, sizeof t - strlen(t) - 1);
  98   }
  99   p = t;
 100   while((ch = (unsigned char)*p++)) {
 101     if(ch >= ' ' && ch <= 126) {
 102       if(n < bufsize) buffer[n++] = ch;
 103     } else {
 104       if(n < bufsize) buffer[n++] = '\\';
 105       if(n < bufsize) buffer[n++] = '0' + ((ch >> 6) & 7);
 106       if(n < bufsize) buffer[n++] = '0' + ((ch >> 3) & 7);
 107       if(n < bufsize) buffer[n++] = '0' + ((ch >> 0) & 7);
 108     }
 109   }
 110   if(n >= bufsize)
 111     n = bufsize - 1;
 112   buffer[n] = 0;
 113 }
 114
 115 /** @brief Log to a file
 116  * @param pri Message priority (as per syslog)
 117  * @param msg Messagge to log
 118  * @param user The @c FILE @c * to log to or NULL for @c stderr
 119  */
 120 static void logfp(int pri, const char *msg, void *user) {
 121   struct timeval tv;
 122   FILE *fp = user ? user : stderr;
 123   /* ...because stderr is not a constant so we can't initialize log_stderr
 124    * sanely */
 125   const char *p;
 126
 127   if(progname)
 128     fprintf(fp, "%s: ", progname);
 129   if(pri <= LOG_ERR)
 130     fputs("ERROR: ", fp);
 131   else if(pri < LOG_DEBUG)
 132     fputs("INFO: ", fp);
 133   else {
 134     if(!debug_only) {
 135       if(!(debug_only = getenv("DISORDER_DEBUG_ONLY")))
 136         debug_only = "";
 137     }
 138     gettimeofday(&tv, 0);
 139     p = debug_filename;
 140     while(!strncmp(p, "../", 3)) p += 3;
 141     if(*debug_only && strcmp(p, debug_only))
 142       return;
 143     fprintf(fp, "%llu.%06lu: %s:%d: ",
 144             (unsigned long long)tv.tv_sec, (unsigned long)tv.tv_usec,
 145             p, debug_lineno);
 146   }
 147   fputs(msg, fp);
 148   fputc('\n', fp);
 149 }
 150
 151 /** @brief Log to syslog */
 152 static void logsyslog(int pri, const char *msg,
 153                       void attribute((unused)) *user) {
 154   if(pri < LOG_DEBUG)
 155     syslog(pri, "%s", msg);
 156   else
 157     syslog(pri, "%s:%d: %s", debug_filename, debug_lineno, msg);
 158 }
 159
 160 /** @brief Log output that writes to @c stderr */
 161 struct log_output log_stderr = { logfp, 0 };
 162
 163 /** @brief Log output that sends to syslog */
 164 struct log_output log_syslog = { logsyslog, 0 };
 165
 166 /** @brief Format and log a message */
 167 static void vlogger(int pri, const char *fmt, va_list ap) {
 168   char buffer[1024];
 169
 170   format(buffer, sizeof buffer, fmt, ap);
 171   log_default->fn(pri, buffer, log_default->user);
 172 }
 173
 174 /** @brief Format and log a message */
 175 static void logger(int pri, const char *fmt, ...) {
 176   va_list ap;
 177
 178   va_start(ap, fmt);
 179   vlogger(pri, fmt, ap);
 180   va_end(ap);
 181 }
 182
 183 /** @brief Format and log a message
 184  * @param pri Message priority (as per syslog)
 185  * @param fmt Format string
 186  * @param errno_value Errno value to include as a string, or 0
 187  * @param ap Argument list
 188  */
 189 void elog(int pri, int errno_value, const char *fmt, va_list ap) {
 190   char buffer[1024];
 191
 192   if(errno_value == 0)
 193     vlogger(pri, fmt, ap);
 194   else {
 195     memset(buffer, 0, sizeof buffer);
 196     byte_vsnprintf(buffer, sizeof buffer, fmt, ap);
 197     buffer[sizeof buffer - 1] = 0;
 198     logger(pri, "%s: %s", buffer, strerror(errno_value));
 199   }
 200 }
 201
 202 #define disorder_fatal fatal
 203 #define disorder_error error
 204 #define disorder_info info
 205
 206 /* shared implementation of vararg functions */
 207 #include "log-impl.h"
 208
 209 /** @brief Log a debug message */
 210 void debug(const char *msg, ...) {
 211   va_list ap;
 212
 213   va_start(ap, msg);
 214   vlogger(LOG_DEBUG, msg, ap);
 215   va_end(ap);
 216 }
 217
 218 /** @brief Set the program name from @c argc */
 219 void set_progname(char **argv) {
 220   if((progname = strrchr(argv[0], '/')))
 221     ++progname;
 222   else
 223     progname = argv[0];
 224 }
 225
 226 /*
 227 Local Variables:
 228 c-basic-offset:2
 229 comment-column:40
 230 End:
 231 */