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

   1 /*
   2  * This file is part of DisOrder.
   3  * Copyright (C) 2004, 2005, 2006 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   p = t;
  98   while((ch = (unsigned char)*p++)) {
  99     if(ch >= ' ' && ch <= 126) {
 100       if(n < bufsize) buffer[n++] = ch;
 101     } else {
 102       if(n < bufsize) buffer[n++] = '\\';
 103       if(n < bufsize) buffer[n++] = '0' + ((ch >> 6) & 7);
 104       if(n < bufsize) buffer[n++] = '0' + ((ch >> 3) & 7);
 105       if(n < bufsize) buffer[n++] = '0' + ((ch >> 0) & 7);
 106     }
 107   }
 108   if(n >= bufsize)
 109     n = bufsize - 1;
 110   buffer[n] = 0;
 111 }
 112
 113 /** @brief Log to a file
 114  * @param pri Message priority (as per syslog)
 115  * @param msg Messagge to log
 116  * @param user The @c FILE @c * to log to or NULL for @c stderr
 117  */
 118 static void logfp(int pri, const char *msg, void *user) {
 119   struct timeval tv;
 120   FILE *fp = user ? user : stderr;
 121   /* ...because stderr is not a constant so we can't initialize log_stderr
 122    * sanely */
 123   const char *p;
 124
 125   if(progname)
 126     fprintf(fp, "%s: ", progname);
 127   if(pri <= LOG_ERR)
 128     fputs("ERROR: ", fp);
 129   else if(pri < LOG_DEBUG)
 130     fputs("INFO: ", fp);
 131   else {
 132     if(!debug_only) {
 133       if(!(debug_only = getenv("DISORDER_DEBUG_ONLY")))
 134         debug_only = "";
 135     }
 136     gettimeofday(&tv, 0);
 137     p = debug_filename;
 138     while(!strncmp(p, "../", 3)) p += 3;
 139     if(*debug_only && strcmp(p, debug_only))
 140       return;
 141     fprintf(fp, "%llu.%06lu: %s:%d: ",
 142             (unsigned long long)tv.tv_sec, (unsigned long)tv.tv_usec,
 143             p, debug_lineno);
 144   }
 145   fputs(msg, fp);
 146   fputc('\n', fp);
 147 }
 148
 149 /** @brief Log to syslog */
 150 static void logsyslog(int pri, const char *msg,
 151                       void attribute((unused)) *user) {
 152   if(pri < LOG_DEBUG)
 153     syslog(pri, "%s", msg);
 154   else
 155     syslog(pri, "%s:%d: %s", debug_filename, debug_lineno, msg);
 156 }
 157
 158 /** @brief Log output that writes to @c stderr */
 159 struct log_output log_stderr = { logfp, 0 };
 160
 161 /** @brief Log output that sends to syslog */
 162 struct log_output log_syslog = { logsyslog, 0 };
 163
 164 /** @brief Format and log a message */
 165 static void vlogger(int pri, const char *fmt, va_list ap) {
 166   char buffer[1024];
 167
 168   format(buffer, sizeof buffer, fmt, ap);
 169   log_default->fn(pri, buffer, log_default->user);
 170 }
 171
 172 /** @brief Format and log a message */
 173 static void logger(int pri, const char *fmt, ...) {
 174   va_list ap;
 175
 176   va_start(ap, fmt);
 177   vlogger(pri, fmt, ap);
 178   va_end(ap);
 179 }
 180
 181 /** @brief Format and log a message
 182  * @param pri Message priority (as per syslog)
 183  * @param fmt Format string
 184  * @param errno_value Errno value to include as a string, or 0
 185  * @param ap Argument list
 186  */
 187 void elog(int pri, int errno_value, const char *fmt, va_list ap) {
 188   char buffer[1024];
 189
 190   if(errno_value == 0)
 191     vlogger(pri, fmt, ap);
 192   else {
 193     memset(buffer, 0, sizeof buffer);
 194     byte_vsnprintf(buffer, sizeof buffer, fmt, ap);
 195     buffer[sizeof buffer - 1] = 0;
 196     logger(pri, "%s: %s", buffer, strerror(errno_value));
 197   }
 198 }
 199
 200 #define disorder_fatal fatal
 201 #define disorder_error error
 202 #define disorder_info info
 203
 204 /* shared implementation of vararg functions */
 205 #include "log-impl.h"
 206
 207 /** @brief Log a debug message */
 208 void debug(const char *msg, ...) {
 209   va_list ap;
 210
 211   va_start(ap, msg);
 212   vlogger(LOG_DEBUG, msg, ap);
 213   va_end(ap);
 214 }
 215
 216 /** @brief Set the program name from @c argc */
 217 void set_progname(char **argv) {
 218   if((progname = strrchr(argv[0], '/')))
 219     ++progname;
 220   else
 221     progname = argv[0];
 222 }
 223
 224 /*
 225 Local Variables:
 226 c-basic-offset:2
 227 comment-column:40
 228 End:
 229 */