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 3 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,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU 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, see <http://www.gnu.org/licenses/>.
  17  */
  18 /** @file lib/log.c @brief Errors and logging
  19  *
  20  * All messages are initially emitted by one of the four functions below.
  21  * debug() is generally invoked via D() so that mostly you just do a test
  22  * rather than a complete subroutine call.
  23  *
  24  * Messages are dispatched via @ref log_default.  This defaults to @ref
  25  * log_stderr.  daemonize() will turn off @ref log_stderr and use @ref
  26  * log_syslog instead.
  27  *
  28  * fatal() will call exitfn() with a nonzero status.  The default value is
  29  * exit(), but it should be set to _exit() anywhere but the 'main line' of the
  30  * program, to guarantee that exit() gets called at most once.
  31  */
  32
  33 #define NO_MEMORY_ALLOCATION
  34 /* because the memory allocation functions report errors */
  35
  36 #include "common.h"
  37
  38 #include <errno.h>
  39 #include <syslog.h>
  40 #include <sys/time.h>
  41 #include <time.h>
  42
  43 #include "log.h"
  44 #include "disorder.h"
  45 #include "printf.h"
  46
  47 /** @brief Definition of a log output */
  48 struct log_output {
  49   /** @brief Function to call */
  50   void (*fn)(int pri, const char *msg, void *user);
  51   /** @brief User data */
  52   void *user;
  53 };
  54
  55 /** @brief Function to call on a fatal error
  56  *
  57  * This is normally @c exit() but in the presence of @c fork() it
  58  * sometimes gets set to @c _exit(). */
  59 void (*exitfn)(int) attribute((noreturn)) = exit;
  60
  61 /** @brief Debug flag */
  62 int debugging;
  63
  64 /** @brief Program name */
  65 const char *progname;
  66
  67 /** @brief Filename for debug messages */
  68 const char *debug_filename;
  69
  70 /** @brief Set to include timestamps in log messages */
  71 int logdate;
  72
  73 /** @brief Line number for debug messages */
  74 int debug_lineno;
  75
  76 /** @brief Pointer to chosen log output structure */
  77 struct log_output *log_default = &log_stderr;
  78
  79 /** @brief Filename to debug for */
  80 static const char *debug_only;
  81
  82 /** @brief Construct log line, encoding special characters
  83  *
  84  * We might be receiving things in any old encoding, or binary rubbish
  85  * in no encoding at all, so escape anything we don't like the look
  86  * of.  We limit the log message to a kilobyte.
  87  */
  88 static void format(char buffer[], size_t bufsize, const char *fmt, va_list ap) {
  89   char t[1024];
  90   const char *p;
  91   int ch;
  92   size_t n = 0;
  93
  94   if(byte_vsnprintf(t, sizeof t, fmt, ap) < 0) {
  95     strcpy(t, "[byte_vsnprintf failed: ");
  96     strncat(t, fmt, sizeof t - strlen(t) - 1);
  97   }
  98   p = t;
  99   while((ch = (unsigned char)*p++)) {
 100     if(ch >= ' ' && ch <= 126) {
 101       if(n < bufsize) buffer[n++] = ch;
 102     } else {
 103       if(n < bufsize) buffer[n++] = '\\';
 104       if(n < bufsize) buffer[n++] = '0' + ((ch >> 6) & 7);
 105       if(n < bufsize) buffer[n++] = '0' + ((ch >> 3) & 7);
 106       if(n < bufsize) buffer[n++] = '0' + ((ch >> 0) & 7);
 107     }
 108   }
 109   if(n >= bufsize)
 110     n = bufsize - 1;
 111   buffer[n] = 0;
 112 }
 113
 114 /** @brief Log to a file
 115  * @param pri Message priority (as per syslog)
 116  * @param msg Messagge to log
 117  * @param user The @c FILE @c * to log to or NULL for @c stderr
 118  */
 119 static void logfp(int pri, const char *msg, void *user) {
 120   struct timeval tv;
 121   FILE *fp = user ? user : stderr;
 122   /* ...because stderr is not a constant so we can't initialize log_stderr
 123    * sanely */
 124   const char *p;
 125
 126   if(logdate) {
 127     char timebuf[64];
 128     struct tm *tm;
 129     gettimeofday(&tv, 0);
 130     tm = localtime(&tv.tv_sec);
 131     strftime(timebuf, sizeof timebuf, "%Y-%m-%d %H:%M:%S %Z", tm);
 132     fprintf(fp, "%s: ", timebuf);
 133   }
 134  if(progname)
 135     fprintf(fp, "%s: ", progname);
 136   if(pri <= LOG_ERR)
 137     fputs("ERROR: ", fp);
 138   else if(pri < LOG_DEBUG)
 139     fputs("INFO: ", fp);
 140   else {
 141     if(!debug_only) {
 142       if(!(debug_only = getenv("DISORDER_DEBUG_ONLY")))
 143         debug_only = "";
 144     }
 145     gettimeofday(&tv, 0);
 146     p = debug_filename;
 147     while(!strncmp(p, "../", 3)) p += 3;
 148     if(*debug_only && strcmp(p, debug_only))
 149       return;
 150     fprintf(fp, "%llu.%06lu: %s:%d: ",
 151             (unsigned long long)tv.tv_sec, (unsigned long)tv.tv_usec,
 152             p, debug_lineno);
 153   }
 154   fputs(msg, fp);
 155   fputc('\n', fp);
 156 }
 157
 158 /** @brief Log to syslog */
 159 static void logsyslog(int pri, const char *msg,
 160                       void attribute((unused)) *user) {
 161   if(pri < LOG_DEBUG)
 162     syslog(pri, "%s", msg);
 163   else
 164     syslog(pri, "%s:%d: %s", debug_filename, debug_lineno, msg);
 165 }
 166
 167 /** @brief Log output that writes to @c stderr */
 168 struct log_output log_stderr = { logfp, 0 };
 169
 170 /** @brief Log output that sends to syslog */
 171 struct log_output log_syslog = { logsyslog, 0 };
 172
 173 /** @brief Format and log a message */
 174 static void vlogger(int pri, const char *fmt, va_list ap) {
 175   char buffer[1024];
 176
 177   format(buffer, sizeof buffer, fmt, ap);
 178   log_default->fn(pri, buffer, log_default->user);
 179 }
 180
 181 /** @brief Format and log a message */
 182 static void logger(int pri, const char *fmt, ...) {
 183   va_list ap;
 184
 185   va_start(ap, fmt);
 186   vlogger(pri, fmt, ap);
 187   va_end(ap);
 188 }
 189
 190 /** @brief Format and log a message
 191  * @param pri Message priority (as per syslog)
 192  * @param fmt Format string
 193  * @param errno_value Errno value to include as a string, or 0
 194  * @param ap Argument list
 195  */
 196 void elog(int pri, int errno_value, const char *fmt, va_list ap) {
 197   char buffer[1024];
 198
 199   if(errno_value == 0)
 200     vlogger(pri, fmt, ap);
 201   else {
 202     memset(buffer, 0, sizeof buffer);
 203     byte_vsnprintf(buffer, sizeof buffer, fmt, ap);
 204     buffer[sizeof buffer - 1] = 0;
 205     logger(pri, "%s: %s", buffer, strerror(errno_value));
 206   }
 207 }
 208
 209 /** @brief Log an error and quit
 210  *
 211  * If @c ${DISORDER_FATAL_ABORT} is defined (as anything) then the process
 212  * is aborted, so you can get a backtrace.
 213  */
 214 void disorder_fatal(int errno_value, const char *msg, ...) {
 215   va_list ap;
 216
 217   va_start(ap, msg);
 218   elog(LOG_CRIT, errno_value, msg, ap);
 219   va_end(ap);
 220   if(getenv("DISORDER_FATAL_ABORT")) abort();
 221   exitfn(EXIT_FAILURE);
 222 }
 223
 224 /** @brief Log an error */
 225 void disorder_error(int errno_value, const char *msg, ...) {
 226   va_list ap;
 227
 228   va_start(ap, msg);
 229   elog(LOG_ERR, errno_value, msg, ap);
 230   va_end(ap);
 231 }
 232
 233 /** @brief Log an informational message */
 234 void disorder_info(const char *msg, ...) {
 235   va_list ap;
 236
 237   va_start(ap, msg);
 238   elog(LOG_INFO, 0, msg, ap);
 239   va_end(ap);
 240 }
 241
 242 /** @brief Log a debug message */
 243 void disorder_debug(const char *msg, ...) {
 244   va_list ap;
 245
 246   va_start(ap, msg);
 247   vlogger(LOG_DEBUG, msg, ap);
 248   va_end(ap);
 249 }
 250
 251 /** @brief Set the program name from @c argc */
 252 void set_progname(char **argv) {
 253   if((progname = strrchr(argv[0], '/')))
 254     ++progname;
 255   else
 256     progname = argv[0];
 257 }
 258
 259 /*
 260 Local Variables:
 261 c-basic-offset:2
 262 comment-column:40
 263 End:
 264 */