m4/debug.c

   1 /* GNU m4 -- A simple macro processor
   2    Copyright (C) 1991-1994, 2006-2010, 2013-2014 Free Software
   3    Foundation, Inc.
   4
   5    This file is part of GNU M4.
   6
   7    GNU M4 is free software: you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation, either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    GNU M4 is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include <config.h>
  22
  23 #include <sys/stat.h>
  24 #include <stdarg.h>
  25
  26 #include "m4private.h"
  27 #include "close-stream.h"
  28
  29 static void set_debug_file (m4 *, const m4_call_info *, FILE *);
  30
  31
  32 \f
  33 /* Function to decode the debugging flags OPTS of length LEN; or
  34    SIZE_MAX if OPTS is NUL-terminated.  If OPTS is NULL, use the
  35    default flags.  Used by main while processing option -d, and by the
  36    builtin debugmode ().  */
  37 int
  38 m4_debug_decode (m4 *context, const char *opts, size_t len)
  39 {
  40   int previous = context->debug_level;
  41   int level;
  42   char mode = '\0';
  43
  44   if (!opts)
  45     opts = "";
  46   if (len == SIZE_MAX)
  47     len = strlen (opts);
  48   if (!len)
  49     level = M4_DEBUG_TRACE_DEFAULT | previous;
  50   else
  51     {
  52       if (*opts == '-' || *opts == '+')
  53         {
  54           len--;
  55           mode = *opts++;
  56         }
  57       for (level = 0; len--; opts++)
  58         {
  59           switch (*opts)
  60             {
  61             case 'a':
  62               level |= M4_DEBUG_TRACE_ARGS;
  63               break;
  64
  65             case 'e':
  66               level |= M4_DEBUG_TRACE_EXPANSION;
  67               break;
  68
  69             case 'q':
  70               level |= M4_DEBUG_TRACE_QUOTE;
  71               break;
  72
  73             case 't':
  74               level |= M4_DEBUG_TRACE_ALL;
  75               break;
  76
  77             case 'l':
  78               level |= M4_DEBUG_TRACE_LINE;
  79               break;
  80
  81             case 'f':
  82               level |= M4_DEBUG_TRACE_FILE;
  83               break;
  84
  85             case 'p':
  86               level |= M4_DEBUG_TRACE_PATH;
  87               break;
  88
  89             case 'c':
  90               level |= M4_DEBUG_TRACE_CALL;
  91               break;
  92
  93             case 'i':
  94               level |= M4_DEBUG_TRACE_INPUT;
  95               break;
  96
  97             case 'x':
  98               level |= M4_DEBUG_TRACE_CALLID;
  99               break;
 100
 101             case 'm':
 102               level |= M4_DEBUG_TRACE_MODULE;
 103               break;
 104
 105             case 's':
 106               level |= M4_DEBUG_TRACE_STACK;
 107               break;
 108
 109             case 'd':
 110               level |= M4_DEBUG_TRACE_DEREF;
 111               break;
 112
 113             case 'o':
 114                level |= M4_DEBUG_TRACE_OUTPUT_DUMPDEF;
 115                break;
 116
 117             case 'V':
 118               level |= M4_DEBUG_TRACE_VERBOSE;
 119               break;
 120
 121             default:
 122               return -1;
 123             }
 124         }
 125     }
 126
 127   switch (mode)
 128     {
 129     case '\0':
 130       /* Replace old level.  */
 131       break;
 132
 133     case '-':
 134       /* Subtract flags.  */
 135       level = previous & ~level;
 136       break;
 137
 138     case '+':
 139       /* Add flags.  */
 140       level |= previous;
 141       break;
 142
 143     default:
 144       assert (!"m4_debug_decode");
 145     }
 146   context->debug_level = level;
 147   return level;
 148 }
 149
 150 /* Change the debug output stream to FP.  If the underlying file is the
 151    same as stdout, use stdout instead so that debug messages appear in the
 152    correct relative position.  Report errors on behalf of CALLER.  */
 153 static void
 154 set_debug_file (m4 *context, const m4_call_info *caller, FILE *fp)
 155 {
 156   FILE *debug_file;
 157   struct stat stdout_stat, debug_stat;
 158
 159   assert (context);
 160
 161   debug_file = m4_get_debug_file (context);
 162   if (debug_file != NULL && debug_file != stderr && debug_file != stdout
 163       && close_stream (debug_file) != 0)
 164     m4_error (context, 0, errno, caller, _("error writing to debug stream"));
 165
 166   debug_file = fp;
 167   m4_set_debug_file (context, fp);
 168
 169   if (debug_file != NULL && debug_file != stdout)
 170     {
 171       if (fstat (fileno (stdout), &stdout_stat) < 0)
 172         return;
 173       if (fstat (fileno (debug_file), &debug_stat) < 0)
 174         return;
 175
 176       /* mingw has a bug where fstat on a regular file reports st_ino
 177          of 0.  On normal system, st_ino should never be 0.  */
 178       if (stdout_stat.st_ino == debug_stat.st_ino
 179           && stdout_stat.st_dev == debug_stat.st_dev
 180           && stdout_stat.st_ino != 0)
 181         {
 182           if (debug_file != stderr && close_stream (debug_file) != 0)
 183             m4_error (context, 0, errno, caller,
 184                       _("error writing to debug stream"));
 185           m4_set_debug_file (context, stdout);
 186         }
 187     }
 188 }
 189
 190 /* Change the debug output to file NAME.  If NAME is NULL, debug
 191    output is reverted to stderr, and if empty debug output is
 192    discarded.  Return true iff the output stream was changed.  Report
 193    errors on behalf of CALLER.  */
 194 bool
 195 m4_debug_set_output (m4 *context, const m4_call_info *caller, const char *name)
 196 {
 197   FILE *fp;
 198
 199   assert (context);
 200
 201   if (name == NULL)
 202     set_debug_file (context, caller, stderr);
 203   else if (*name == '\0')
 204     set_debug_file (context, caller, NULL);
 205   else
 206     {
 207       fp = fopen (name, "a");
 208       if (fp == NULL)
 209         return false;
 210
 211       if (set_cloexec_flag (fileno (fp), true) != 0)
 212         m4_warn (context, errno, caller,
 213                  _("cannot protect debug file across forks"));
 214       set_debug_file (context, caller, fp);
 215     }
 216   return true;
 217 }
 218
 219 /* Print the header of a one-line debug message, starting with "m4debug:".  */
 220 void
 221 m4_debug_message_prefix (m4 *context)
 222 {
 223   FILE *debug_file;
 224
 225   assert (context);
 226
 227   debug_file = m4_get_debug_file (context);
 228   fputs ("m4debug:", debug_file);
 229   if (m4_get_current_line (context))
 230     {
 231       if (m4_is_debug_bit (context, M4_DEBUG_TRACE_FILE))
 232         xfprintf (debug_file, "%s:", m4_get_current_file (context));
 233       if (m4_is_debug_bit (context, M4_DEBUG_TRACE_LINE))
 234         xfprintf (debug_file, "%d:", m4_get_current_line (context));
 235     }
 236   putc (' ', debug_file);
 237 }
 238
 239 /* If the current debug mode includes MODE, and there is a current
 240    debug file, then output a debug message described by FORMAT.  A
 241    message header is supplied, as well as a trailing newline.  */
 242 void
 243 m4_debug_message (m4 *context, int mode, const char *format, ...)
 244 {
 245   /* Check that mode has exactly one bit set.  */
 246   assert (mode && (mode & (mode - 1)) == 0);
 247   assert (format);
 248
 249   if (m4_get_debug_file (context) != NULL
 250       && m4_is_debug_bit (context, mode))
 251     {
 252       va_list args;
 253
 254       m4_debug_message_prefix (context);
 255       va_start (args, format);
 256       xvfprintf (m4_get_debug_file (context), format, args);
 257       va_end (args);
 258       putc ('\n', m4_get_debug_file (context));
 259     }
 260 }