src/debug.c

   1 /* GNU m4 -- A simple macro processor
   2
   3    Copyright (C) 1991, 1992, 1993, 1994, 2004, 2006 Free Software
   4    Foundation, Inc.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19    02110-1301  USA
  20 */
  21
  22 #include "m4.h"
  23
  24 #include <stdarg.h>
  25 #include <sys/stat.h>
  26
  27 /* File for debugging output.  */
  28 FILE *debug = NULL;
  29
  30 /* Obstack for trace messages.  */
  31 static struct obstack trace;
  32
  33 extern int expansion_level;
  34
  35 static void debug_set_file (FILE *);
  36
  37 /*----------------------------------.
  38 | Initialise the debugging module.  |
  39 `----------------------------------*/
  40
  41 void
  42 debug_init (void)
  43 {
  44   debug_set_file (stderr);
  45   obstack_init (&trace);
  46 }
  47 \f
  48 /*-----------------------------------------------------------------.
  49 | Function to decode the debugging flags OPTS.  Used by main while |
  50 | processing option -d, and by the builtin debugmode ().           |
  51 `-----------------------------------------------------------------*/
  52
  53 int
  54 debug_decode (const char *opts)
  55 {
  56   int level;
  57
  58   if (opts == NULL || *opts == '\0')
  59     level = DEBUG_TRACE_DEFAULT;
  60   else
  61     {
  62       for (level = 0; *opts; opts++)
  63         {
  64           switch (*opts)
  65             {
  66             case 'a':
  67               level |= DEBUG_TRACE_ARGS;
  68               break;
  69
  70             case 'e':
  71               level |= DEBUG_TRACE_EXPANSION;
  72               break;
  73
  74             case 'q':
  75               level |= DEBUG_TRACE_QUOTE;
  76               break;
  77
  78             case 't':
  79               level |= DEBUG_TRACE_ALL;
  80               break;
  81
  82             case 'l':
  83               level |= DEBUG_TRACE_LINE;
  84               break;
  85
  86             case 'f':
  87               level |= DEBUG_TRACE_FILE;
  88               break;
  89
  90             case 'p':
  91               level |= DEBUG_TRACE_PATH;
  92               break;
  93
  94             case 'c':
  95               level |= DEBUG_TRACE_CALL;
  96               break;
  97
  98             case 'i':
  99               level |= DEBUG_TRACE_INPUT;
 100               break;
 101
 102             case 'x':
 103               level |= DEBUG_TRACE_CALLID;
 104               break;
 105
 106             case 'V':
 107               level |= DEBUG_TRACE_VERBOSE;
 108               break;
 109
 110             default:
 111               return -1;
 112             }
 113         }
 114     }
 115
 116   /* This is to avoid screwing up the trace output due to changes in the
 117      debug_level.  */
 118
 119   obstack_free (&trace, obstack_finish (&trace));
 120
 121   return level;
 122 }
 123
 124 /*------------------------------------------------------------------------.
 125 | Change the debug output stream to FP.  If the underlying file is the    |
 126 | same as stdout, use stdout instead so that debug messages appear in the |
 127 | correct relative position.                                              |
 128 `------------------------------------------------------------------------*/
 129
 130 static void
 131 debug_set_file (FILE *fp)
 132 {
 133   struct stat stdout_stat, debug_stat;
 134
 135   if (debug != NULL && debug != stderr && debug != stdout
 136       && close_stream (debug) != 0)
 137     {
 138       M4ERROR ((warning_status, errno, "error writing to debug stream"));
 139       retcode = EXIT_FAILURE;
 140     }
 141   debug = fp;
 142
 143   if (debug != NULL && debug != stdout)
 144     {
 145       if (fstat (STDOUT_FILENO, &stdout_stat) < 0)
 146         return;
 147       if (fstat (fileno (debug), &debug_stat) < 0)
 148         return;
 149
 150       /* mingw has a bug where fstat on a regular file reports st_ino
 151          of 0.  On normal system, st_ino should never be 0.  */
 152       if (stdout_stat.st_ino == debug_stat.st_ino
 153           && stdout_stat.st_dev == debug_stat.st_dev
 154           && stdout_stat.st_ino != 0)
 155         {
 156           if (debug != stderr && close_stream (debug) != 0)
 157             {
 158               M4ERROR ((warning_status, errno,
 159                         "error writing to debug stream"));
 160               retcode = EXIT_FAILURE;
 161             }
 162           debug = stdout;
 163         }
 164     }
 165 }
 166
 167 /*-----------------------------------------------------------.
 168 | Serialize files.  Used before executing a system command.  |
 169 `-----------------------------------------------------------*/
 170
 171 void
 172 debug_flush_files (void)
 173 {
 174   fflush (stdout);
 175   fflush (stderr);
 176   if (debug != NULL && debug != stdout && debug != stderr)
 177     fflush (debug);
 178   /* POSIX requires that if m4 doesn't consume all input, but stdin is
 179      opened on a seekable file, that the file pointer be left at the
 180      next character on exit (but places no restrictions on the file
 181      pointer location on a non-seekable file).  It also requires that
 182      fflush() followed by fseek() on an input file set the underlying
 183      file pointer.  However, fflush() on a non-seekable file can lose
 184      buffered data, which we might otherwise want to process after
 185      syscmd.  Hence, we must check whether stdin is seekable.  We must
 186      also be tolerant of operating with stdin closed, so we don't
 187      report any failures in this attempt.  The stdio-safer module and
 188      friends are essential, so that if stdin was closed, this lseek is
 189      not on some other file that we have since opened.  Mingw has bugs
 190      when using fseek on text files, so we only strive for POSIX
 191      behavior when we detect a UNIX environment.  */
 192 #if UNIX
 193   if (lseek (STDIN_FILENO, 0, SEEK_CUR) >= 0
 194       && fflush (stdin) == 0)
 195     {
 196       fseek (stdin, 0, SEEK_CUR);
 197     }
 198 #endif /* UNIX */
 199 }
 200
 201 /*-------------------------------------------------------------------------.
 202 | Change the debug output to file NAME.  If NAME is NULL, debug output is  |
 203 | reverted to stderr, and if empty debug output is discarded.  Return true |
 204 | iff the output stream was changed.                                       |
 205 `-------------------------------------------------------------------------*/
 206
 207 bool
 208 debug_set_output (const char *name)
 209 {
 210   FILE *fp;
 211
 212   if (name == NULL)
 213     debug_set_file (stderr);
 214   else if (*name == '\0')
 215     debug_set_file (NULL);
 216   else
 217     {
 218       fp = fopen (name, "a");
 219       if (fp == NULL)
 220         return false;
 221
 222       if (set_cloexec_flag (fileno (fp), true) != 0)
 223         M4ERROR ((warning_status, errno,
 224                   "Warning: cannot protect debug file across forks"));
 225       debug_set_file (fp);
 226     }
 227   return true;
 228 }
 229
 230 /*-----------------------------------------------------------------------.
 231 | Print the header of a one-line debug message, starting by "m4 debug".  |
 232 `-----------------------------------------------------------------------*/
 233
 234 void
 235 debug_message_prefix (void)
 236 {
 237   fprintf (debug, "m4debug:");
 238   if (current_line)
 239   {
 240     if (debug_level & DEBUG_TRACE_FILE)
 241       fprintf (debug, "%s:", current_file);
 242     if (debug_level & DEBUG_TRACE_LINE)
 243       fprintf (debug, "%d:", current_line);
 244   }
 245   putc (' ', debug);
 246 }
 247 \f
 248 /* The rest of this file contains the functions for macro tracing output.
 249    All tracing output for a macro call is collected on an obstack TRACE,
 250    and printed whenever the line is complete.  This prevents tracing
 251    output from interfering with other debug messages generated by the
 252    various builtins.  */
 253
 254 /*---------------------------------------------------------------------.
 255 | Tracing output is formatted here, by a simplified printf-to-obstack  |
 256 | function trace_format ().  Understands only %S, %s, %d, %l (optional |
 257 | left quote) and %r (optional right quote).                           |
 258 `---------------------------------------------------------------------*/
 259
 260 static void
 261 trace_format (const char *fmt, ...)
 262 {
 263   va_list args;
 264   char ch;
 265
 266   int d;
 267   char nbuf[32];
 268   const char *s;
 269   int slen;
 270   int maxlen;
 271
 272   va_start (args, fmt);
 273
 274   while (true)
 275     {
 276       while ((ch = *fmt++) != '\0' && ch != '%')
 277         obstack_1grow (&trace, ch);
 278
 279       if (ch == '\0')
 280         break;
 281
 282       maxlen = 0;
 283       switch (*fmt++)
 284         {
 285         case 'S':
 286           maxlen = max_debug_argument_length;
 287           /* fall through */
 288
 289         case 's':
 290           s = va_arg (args, const char *);
 291           break;
 292
 293         case 'l':
 294           s = (debug_level & DEBUG_TRACE_QUOTE) ? lquote.string : "";
 295           break;
 296
 297         case 'r':
 298           s = (debug_level & DEBUG_TRACE_QUOTE) ? rquote.string : "";
 299           break;
 300
 301         case 'd':
 302           d = va_arg (args, int);
 303           sprintf (nbuf, "%d", d);
 304           s = nbuf;
 305           break;
 306
 307         default:
 308           s = "";
 309           break;
 310         }
 311
 312       slen = strlen (s);
 313       if (maxlen == 0 || maxlen > slen)
 314         obstack_grow (&trace, s, slen);
 315       else
 316         {
 317           obstack_grow (&trace, s, maxlen);
 318           obstack_grow (&trace, "...", 3);
 319         }
 320     }
 321
 322   va_end (args);
 323 }
 324
 325 /*------------------------------------------------------------------.
 326 | Format the standard header attached to all tracing output lines.  |
 327 `------------------------------------------------------------------*/
 328
 329 static void
 330 trace_header (int id)
 331 {
 332   trace_format ("m4trace:");
 333   if (current_line)
 334     {
 335       if (debug_level & DEBUG_TRACE_FILE)
 336         trace_format ("%s:", current_file);
 337       if (debug_level & DEBUG_TRACE_LINE)
 338         trace_format ("%d:", current_line);
 339     }
 340   trace_format (" -%d- ", expansion_level);
 341   if (debug_level & DEBUG_TRACE_CALLID)
 342     trace_format ("id %d: ", id);
 343 }
 344
 345 /*----------------------------------------------------.
 346 | Print current tracing line, and clear the obstack.  |
 347 `----------------------------------------------------*/
 348
 349 static void
 350 trace_flush (void)
 351 {
 352   char *line;
 353
 354   obstack_1grow (&trace, '\0');
 355   line = (char *) obstack_finish (&trace);
 356   DEBUG_PRINT1 ("%s\n", line);
 357   obstack_free (&trace, line);
 358 }
 359
 360 /*-------------------------------------------------------------.
 361 | Do pre-argument-collction tracing for macro NAME.  Used from |
 362 | expand_macro ().                                             |
 363 `-------------------------------------------------------------*/
 364
 365 void
 366 trace_prepre (const char *name, int id)
 367 {
 368   trace_header (id);
 369   trace_format ("%s ...", name);
 370   trace_flush ();
 371 }
 372
 373 /*-----------------------------------------------------------------------.
 374 | Format the parts of a trace line, that can be made before the macro is |
 375 | actually expanded.  Used from expand_macro ().                         |
 376 `-----------------------------------------------------------------------*/
 377
 378 void
 379 trace_pre (const char *name, int id, int argc, token_data **argv)
 380 {
 381   int i;
 382   const builtin *bp;
 383
 384   trace_header (id);
 385   trace_format ("%s", name);
 386
 387   if (argc > 1 && (debug_level & DEBUG_TRACE_ARGS))
 388     {
 389       trace_format ("(");
 390
 391       for (i = 1; i < argc; i++)
 392         {
 393           if (i != 1)
 394             trace_format (", ");
 395
 396           switch (TOKEN_DATA_TYPE (argv[i]))
 397             {
 398             case TOKEN_TEXT:
 399               trace_format ("%l%S%r", TOKEN_DATA_TEXT (argv[i]));
 400               break;
 401
 402             case TOKEN_FUNC:
 403               bp = find_builtin_by_addr (TOKEN_DATA_FUNC (argv[i]));
 404               if (bp == NULL)
 405                 {
 406                   M4ERROR ((warning_status, 0, "\
 407 INTERNAL ERROR: builtin not found in builtin table! (trace_pre ())"));
 408                   abort ();
 409                 }
 410               trace_format ("<%s>", bp->name);
 411               break;
 412
 413             default:
 414               M4ERROR ((warning_status, 0,
 415                         "INTERNAL ERROR: bad token data type (trace_pre ())"));
 416               abort ();
 417             }
 418
 419         }
 420       trace_format (")");
 421     }
 422
 423   if (debug_level & DEBUG_TRACE_CALL)
 424     {
 425       trace_format (" -> ???");
 426       trace_flush ();
 427     }
 428 }
 429
 430 /*-------------------------------------------------------------------.
 431 | Format the final part of a trace line and print it all.  Used from |
 432 | expand_macro ().                                                   |
 433 `-------------------------------------------------------------------*/
 434
 435 void
 436 trace_post (const char *name, int id, int argc, token_data **argv,
 437             const char *expanded)
 438 {
 439   if (debug_level & DEBUG_TRACE_CALL)
 440     {
 441       trace_header (id);
 442       trace_format ("%s%s", name, (argc > 1) ? "(...)" : "");
 443     }
 444
 445   if (expanded && (debug_level & DEBUG_TRACE_EXPANSION))
 446     trace_format (" -> %l%S%r", expanded);
 447   trace_flush ();
 448 }