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

   1 /*
   2  * This file is part of DisOrder.
   3  * Copyright (C) 2004-9, 2013 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
  21  * below.  disorder_debug() is generally invoked via D() so that
  22  * mostly you just do a test 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  * disorder_fatal() will call exitfn() with a nonzero status.  The
  29  * default value is exit(), but it should be set to _exit() anywhere
  30  * but the 'main line' of the program, to guarantee that exit() gets
  31  * called at most once.
  32  */
  33
  34 #define NO_MEMORY_ALLOCATION
  35 /* because the memory allocation functions report errors */
  36
  37 #include "common.h"
  38
  39 #include <errno.h>
  40 #include <sys/types.h>
  41 #if HAVE_SYSLOG_H
  42 # include <syslog.h>
  43 #endif
  44 #if HAVE_SYS_TIME_H
  45 # include <sys/time.h>
  46 #endif
  47 #if HAVE_SYS_SOCKET_H
  48 # include <sys/socket.h>
  49 #endif
  50 #if HAVE_NETDB_H
  51 # include <netdb.h>
  52 #endif
  53 #include <time.h>
  54
  55 #include "log.h"
  56 #include "disorder.h"
  57 #include "printf.h"
  58
  59 /** @brief Definition of a log output */
  60 struct log_output {
  61   /** @brief Function to call */
  62   void (*fn)(int pri, const char *msg, void *user);
  63   /** @brief User data */
  64   void *user;
  65 };
  66
  67 /** @brief Function to call on a fatal error
  68  *
  69  * This is normally @c exit() but in the presence of @c fork() it
  70  * sometimes gets set to @c _exit(). */
  71 void (*exitfn)(int) attribute((noreturn)) = exit;
  72
  73 /** @brief Debug flag */
  74 int debugging;
  75
  76 /** @brief Program name */
  77 const char *progname;
  78
  79 /** @brief Filename for debug messages */
  80 const char *debug_filename;
  81
  82 /** @brief Set to include timestamps in log messages */
  83 int logdate;
  84
  85 /** @brief Line number for debug messages */
  86 int debug_lineno;
  87
  88 /** @brief Pointer to chosen log output structure */
  89 struct log_output *log_default = &log_stderr;
  90
  91 /** @brief Filename to debug for */
  92 static const char *debug_only;
  93
  94 /** @brief Construct log line, encoding special characters
  95  *
  96  * We might be receiving things in any old encoding, or binary rubbish
  97  * in no encoding at all, so escape anything we don't like the look
  98  * of.  We limit the log message to a kilobyte.
  99  */
 100 static void format(char buffer[], size_t bufsize, const char *fmt, va_list ap) {
 101   char t[1024];
 102   const char *p;
 103   int ch;
 104   size_t n = 0;
 105
 106   if(byte_vsnprintf(t, sizeof t, fmt, ap) < 0) {
 107     strcpy(t, "[byte_vsnprintf failed: ");
 108     strncat(t, fmt, sizeof t - strlen(t) - 1);
 109   }
 110   p = t;
 111   while((ch = (unsigned char)*p++)) {
 112     if(ch >= ' ' && ch <= 126) {
 113       if(n < bufsize) buffer[n++] = ch;
 114     } else {
 115       if(n < bufsize) buffer[n++] = '\\';
 116       if(n < bufsize) buffer[n++] = '0' + ((ch >> 6) & 7);
 117       if(n < bufsize) buffer[n++] = '0' + ((ch >> 3) & 7);
 118       if(n < bufsize) buffer[n++] = '0' + ((ch >> 0) & 7);
 119     }
 120   }
 121   if(n >= bufsize)
 122     n = bufsize - 1;
 123   buffer[n] = 0;
 124 }
 125
 126 /** @brief Log to a file
 127  * @param pri Message priority (as per syslog)
 128  * @param msg Messagge to log
 129  * @param user The @c FILE @c * to log to or NULL for @c stderr
 130  */
 131 static void logfp(int pri, const char *msg, void *user) {
 132   struct timeval tv;
 133   FILE *fp = user ? user : stderr;
 134   /* ...because stderr is not a constant so we can't initialize log_stderr
 135    * sanely */
 136   const char *p;
 137
 138   if(logdate) {
 139     char timebuf[64];
 140     struct tm *tm;
 141     gettimeofday(&tv, 0);
 142     tm = localtime(&tv.tv_sec);
 143     strftime(timebuf, sizeof timebuf, "%Y-%m-%d %H:%M:%S %Z", tm);
 144     fprintf(fp, "%s: ", timebuf);
 145   }
 146  if(progname)
 147     fprintf(fp, "%s: ", progname);
 148   if(pri <= LOG_ERR)
 149     fputs("ERROR: ", fp);
 150   else if(pri < LOG_DEBUG)
 151     fputs("INFO: ", fp);
 152   else {
 153     if(!debug_only) {
 154       if(!(debug_only = getenv("DISORDER_DEBUG_ONLY")))
 155         debug_only = "";
 156     }
 157     gettimeofday(&tv, 0);
 158     p = debug_filename;
 159     while(!strncmp(p, "../", 3)) p += 3;
 160     if(*debug_only && strcmp(p, debug_only))
 161       return;
 162     fprintf(fp, "%llu.%06lu: %s:%d: ",
 163             (unsigned long long)tv.tv_sec, (unsigned long)tv.tv_usec,
 164             p, debug_lineno);
 165   }
 166   fputs(msg, fp);
 167   fputc('\n', fp);
 168 }
 169
 170 #if HAVE_SYSLOG_H
 171 /** @brief Log to syslog */
 172 static void logsyslog(int pri, const char *msg,
 173                       void attribute((unused)) *user) {
 174   if(pri < LOG_DEBUG)
 175     syslog(pri, "%s", msg);
 176   else
 177     syslog(pri, "%s:%d: %s", debug_filename, debug_lineno, msg);
 178 }
 179 #endif
 180
 181 /** @brief Log output that writes to @c stderr */
 182 struct log_output log_stderr = { logfp, 0 };
 183
 184 #if HAVE_SYSLOG_H
 185 /** @brief Log output that sends to syslog */
 186 struct log_output log_syslog = { logsyslog, 0 };
 187 #endif
 188
 189 /** @brief Format and log a message */
 190 static void vlogger(int pri, const char *fmt, va_list ap) {
 191   char buffer[1024];
 192
 193   format(buffer, sizeof buffer, fmt, ap);
 194   log_default->fn(pri, buffer, log_default->user);
 195 }
 196
 197 /** @brief Format and log a message */
 198 static void logger(int pri, const char *fmt, ...) {
 199   va_list ap;
 200
 201   va_start(ap, fmt);
 202   vlogger(pri, fmt, ap);
 203   va_end(ap);
 204 }
 205
 206 /** @brief Format and log a message
 207  * @param pri Message priority (as per syslog)
 208  * @param ec Error class
 209  * @param fmt Format string
 210  * @param errno_value Errno value to include as a string, or 0
 211  * @param ap Argument list
 212  */
 213 void elog(int pri, enum error_class ec, int errno_value, const char *fmt, va_list ap) {
 214   char buffer[1024];
 215   char errbuf[1024];
 216
 217   if(errno_value == 0)
 218     vlogger(pri, fmt, ap);
 219   else {
 220     memset(buffer, 0, sizeof buffer);
 221     byte_vsnprintf(buffer, sizeof buffer, fmt, ap);
 222     buffer[sizeof buffer - 1] = 0;
 223     logger(pri, "%s: %s", buffer,
 224            format_error(ec, errno_value, errbuf, sizeof errbuf));
 225   }
 226 }
 227
 228 /** @brief Log an error and quit
 229  *
 230  * If @c ${DISORDER_FATAL_ABORT} is defined (as anything) then the process
 231  * is aborted, so you can get a backtrace.
 232  */
 233 void disorder_fatal(int errno_value, const char *msg, ...) {
 234   va_list ap;
 235
 236   va_start(ap, msg);
 237   elog(LOG_CRIT, ec_errno, errno_value, msg, ap);
 238   va_end(ap);
 239   if(getenv("DISORDER_FATAL_ABORT")) abort();
 240   exitfn(EXIT_FAILURE);
 241 }
 242
 243 /** @brief Log an error and quit
 244  *
 245  * If @c ${DISORDER_FATAL_ABORT} is defined (as anything) then the process
 246  * is aborted, so you can get a backtrace.
 247  */
 248 void disorder_fatal_ec(enum error_class ec, int errno_value, const char *msg, ...) {
 249   va_list ap;
 250
 251   va_start(ap, msg);
 252   elog(LOG_CRIT, ec, errno_value, msg, ap);
 253   va_end(ap);
 254   if(getenv("DISORDER_FATAL_ABORT")) abort();
 255   exitfn(EXIT_FAILURE);
 256 }
 257
 258 /** @brief Log an error */
 259 void disorder_error(int errno_value, const char *msg, ...) {
 260   va_list ap;
 261
 262   va_start(ap, msg);
 263   elog(LOG_ERR, ec_errno, errno_value, msg, ap);
 264   va_end(ap);
 265 }
 266
 267 /** @brief Log an error */
 268 void disorder_error_ec(enum error_class ec, int errno_value, const char *msg, ...) {
 269   va_list ap;
 270
 271   va_start(ap, msg);
 272   elog(LOG_ERR, ec, errno_value, msg, ap);
 273   va_end(ap);
 274 }
 275
 276 /** @brief Log an informational message */
 277 void disorder_info(const char *msg, ...) {
 278   va_list ap;
 279
 280   va_start(ap, msg);
 281   elog(LOG_INFO, ec_none, 0, msg, ap);
 282   va_end(ap);
 283 }
 284
 285 /** @brief Log a debug message */
 286 void disorder_debug(const char *msg, ...) {
 287   va_list ap;
 288
 289   va_start(ap, msg);
 290   vlogger(LOG_DEBUG, msg, ap);
 291   va_end(ap);
 292 }
 293
 294 /** @brief Set the program name from @c argc */
 295 void set_progname(char **argv) {
 296   if((progname = strrchr(argv[0], '/')))
 297     ++progname;
 298   else
 299     progname = argv[0];
 300 }
 301
 302 /** @brief Format an error string
 303  * @param ec Error class
 304  * @param err Error code (interpretation defined by @p ec)
 305  * @param buffer Output buffer
 306  * @param bufsize Size of output buffer
 307  * @return Pointer to error string
 308  *
 309  * The return value may or may not be @p buffer.
 310  */
 311 #pragma GCC diagnostic ignored "-Wunused-parameter"
 312 const char *format_error(enum error_class ec, int err, char buffer[], size_t bufsize) {
 313   switch(ec) {
 314   default:
 315     return strerror(err);
 316   case ec_getaddrinfo:
 317     return gai_strerror(err);
 318   case ec_none:
 319     return "(none)";
 320   }
 321 }
 322
 323 /*
 324 Local Variables:
 325 c-basic-offset:2
 326 comment-column:40
 327 End:
 328 */