source/param/params.c

   1 /* -------------------------------------------------------------------------- **
   2  * Microsoft Network Services for Unix, AKA., Andrew Tridgell's SAMBA.
   3  *
   4  * This module Copyright (C) 1990-1998 Karl Auer
   5  *
   6  * Rewritten almost completely by Christopher R. Hertel
   7  * at the University of Minnesota, September, 1997.
   8  * This module Copyright (C) 1997-1998 by the University of Minnesota
   9  * -------------------------------------------------------------------------- **
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  24  *
  25  * -------------------------------------------------------------------------- **
  26  *
  27  * Module name: params
  28  *
  29  * -------------------------------------------------------------------------- **
  30  *
  31  *  This module performs lexical analysis and initial parsing of a
  32  *  Windows-like parameter file.  It recognizes and handles four token
  33  *  types:  section-name, parameter-name, parameter-value, and
  34  *  end-of-file.  Comments and line continuation are handled
  35  *  internally.
  36  *
  37  *  The entry point to the module is function pm_process().  This
  38  *  function opens the source file, calls the Parse() function to parse
  39  *  the input, and then closes the file when either the EOF is reached
  40  *  or a fatal error is encountered.
  41  *
  42  *  A sample parameter file might look like this:
  43  *
  44  *  [section one]
  45  *  parameter one = value string
  46  *  parameter two = another value
  47  *  [section two]
  48  *  new parameter = some value or t'other
  49  *
  50  *  The parameter file is divided into sections by section headers:
  51  *  section names enclosed in square brackets (eg. [section one]).
  52  *  Each section contains parameter lines, each of which consist of a
  53  *  parameter name and value delimited by an equal sign.  Roughly, the
  54  *  syntax is:
  55  *
  56  *    <file>            :==  { <section> } EOF
  57  *
  58  *    <section>         :==  <section header> { <parameter line> }
  59  *
  60  *    <section header>  :==  '[' NAME ']'
  61  *
  62  *    <parameter line>  :==  NAME '=' VALUE '\n'
  63  *
  64  *  Blank lines and comment lines are ignored.  Comment lines are lines
  65  *  beginning with either a semicolon (';') or a pound sign ('#').
  66  *
  67  *  All whitespace in section names and parameter names is compressed
  68  *  to single spaces.  Leading and trailing whitespace is stipped from
  69  *  both names and values.
  70  *
  71  *  Only the first equals sign in a parameter line is significant.
  72  *  Parameter values may contain equals signs, square brackets and
  73  *  semicolons.  Internal whitespace is retained in parameter values,
  74  *  with the exception of the '\r' character, which is stripped for
  75  *  historic reasons.  Parameter names may not start with a left square
  76  *  bracket, an equal sign, a pound sign, or a semicolon, because these
  77  *  are used to identify other tokens.
  78  *
  79  * -------------------------------------------------------------------------- **
  80  */
  81
  82 #include "includes.h"
  83
  84 /* -------------------------------------------------------------------------- **
  85  * Constants...
  86  */
  87
  88 #define BUFR_INC 1024
  89
  90
  91 /* -------------------------------------------------------------------------- **
  92  * Variables...
  93  *
  94  *  DEBUGLEVEL  - The ubiquitous DEBUGLEVEL.  This determines which DEBUG()
  95  *                messages will be produced.
  96  *  bufr        - pointer to a global buffer.  This is probably a kludge,
  97  *                but it was the nicest kludge I could think of (for now).
  98  *  bSize       - The size of the global buffer <bufr>.
  99  */
 100
 101 static char *bufr  = NULL;
 102 static int   bSize = 0;
 103
 104 /* we can't use FILE* due to the 256 fd limit - use this cheap hack
 105    instead */
 106 typedef struct {
 107         char *buf;
 108         char *p;
 109         size_t size;
 110 } myFILE;
 111
 112 static int mygetc(myFILE *f)
 113 {
 114         if (f->p >= f->buf+f->size) return EOF;
 115         /* be sure to return chars >127 as positive values */
 116         return (int)( *(f->p++) & 0x00FF );
 117 }
 118
 119 static void myfile_close(myFILE *f)
 120 {
 121         if (!f) return;
 122         SAFE_FREE(f->buf);
 123         SAFE_FREE(f);
 124 }
 125
 126 /* -------------------------------------------------------------------------- **
 127  * Functions...
 128  */
 129
 130 static int EatWhitespace( myFILE *InFile )
 131   /* ------------------------------------------------------------------------ **
 132    * Scan past whitespace (see ctype(3C)) and return the first non-whitespace
 133    * character, or newline, or EOF.
 134    *
 135    *  Input:  InFile  - Input source.
 136    *
 137    *  Output: The next non-whitespace character in the input stream.
 138    *
 139    *  Notes:  Because the config files use a line-oriented grammar, we
 140    *          explicitly exclude the newline character from the list of
 141    *          whitespace characters.
 142    *        - Note that both EOF (-1) and the nul character ('\0') are
 143    *          considered end-of-file markers.
 144    *
 145    * ------------------------------------------------------------------------ **
 146    */
 147   {
 148   int c;
 149
 150   for( c = mygetc( InFile ); isspace( c ) && ('\n' != c); c = mygetc( InFile ) )
 151     ;
 152   return( c );
 153   } /* EatWhitespace */
 154
 155 static int EatComment( myFILE *InFile )
 156   /* ------------------------------------------------------------------------ **
 157    * Scan to the end of a comment.
 158    *
 159    *  Input:  InFile  - Input source.
 160    *
 161    *  Output: The character that marks the end of the comment.  Normally,
 162    *          this will be a newline, but it *might* be an EOF.
 163    *
 164    *  Notes:  Because the config files use a line-oriented grammar, we
 165    *          explicitly exclude the newline character from the list of
 166    *          whitespace characters.
 167    *        - Note that both EOF (-1) and the nul character ('\0') are
 168    *          considered end-of-file markers.
 169    *
 170    * ------------------------------------------------------------------------ **
 171    */
 172   {
 173   int c;
 174
 175   for( c = mygetc( InFile ); ('\n'!=c) && (EOF!=c) && (c>0); c = mygetc( InFile ) )
 176     ;
 177   return( c );
 178   } /* EatComment */
 179
 180 /*****************************************************************************
 181  * Scan backards within a string to discover if the last non-whitespace
 182  * character is a line-continuation character ('\\').
 183  *
 184  *  Input:  line  - A pointer to a buffer containing the string to be
 185  *                  scanned.
 186  *          pos   - This is taken to be the offset of the end of the
 187  *                  string.  This position is *not* scanned.
 188  *
 189  *  Output: The offset of the '\\' character if it was found, or -1 to
 190  *          indicate that it was not.
 191  *
 192  *****************************************************************************/
 193
 194 static int Continuation(char *line, int pos )
 195 {
 196         pos--;
 197         while( (pos >= 0) && isspace((int)line[pos]))
 198                 pos--;
 199
 200         return (((pos >= 0) && ('\\' == line[pos])) ? pos : -1 );
 201 }
 202
 203
 204 static BOOL Section( myFILE *InFile, BOOL (*sfunc)(const char *) )
 205   /* ------------------------------------------------------------------------ **
 206    * Scan a section name, and pass the name to function sfunc().
 207    *
 208    *  Input:  InFile  - Input source.
 209    *          sfunc   - Pointer to the function to be called if the section
 210    *                    name is successfully read.
 211    *
 212    *  Output: True if the section name was read and True was returned from
 213    *          <sfunc>.  False if <sfunc> failed or if a lexical error was
 214    *          encountered.
 215    *
 216    * ------------------------------------------------------------------------ **
 217    */
 218   {
 219   int   c;
 220   int   i;
 221   int   end;
 222   const char *func  = "params.c:Section() -";
 223
 224   i = 0;      /* <i> is the offset of the next free byte in bufr[] and  */
 225   end = 0;    /* <end> is the current "end of string" offset.  In most  */
 226               /* cases these will be the same, but if the last          */
 227               /* character written to bufr[] is a space, then <end>     */
 228               /* will be one less than <i>.                             */
 229
 230   c = EatWhitespace( InFile );    /* We've already got the '['.  Scan */
 231                                   /* past initial white space.        */
 232
 233   while( (EOF != c) && (c > 0) )
 234     {
 235
 236     /* Check that the buffer is big enough for the next character. */
 237     if( i > (bSize - 2) )
 238       {
 239       char *tb;
 240
 241       tb = Realloc( bufr, bSize +BUFR_INC );
 242       if( NULL == tb )
 243         {
 244         DEBUG(0, ("%s Memory re-allocation failure.", func) );
 245         return( False );
 246         }
 247       bufr = tb;
 248       bSize += BUFR_INC;
 249       }
 250
 251     /* Handle a single character. */
 252     switch( c )
 253       {
 254       case ']':                       /* Found the closing bracket.         */
 255         bufr[end] = '\0';
 256         if( 0 == end )                  /* Don't allow an empty name.       */
 257           {
 258           DEBUG(0, ("%s Empty section name in configuration file.\n", func ));
 259           return( False );
 260           }
 261         if( !sfunc(bufr) )            /* Got a valid name.  Deal with it. */
 262           return( False );
 263         (void)EatComment( InFile );     /* Finish off the line.             */
 264         return( True );
 265
 266       case '\n':                      /* Got newline before closing ']'.    */
 267         i = Continuation( bufr, i );    /* Check for line continuation.     */
 268         if( i < 0 )
 269           {
 270           bufr[end] = '\0';
 271           DEBUG(0, ("%s Badly formed line in configuration file: %s\n",
 272                    func, bufr ));
 273           return( False );
 274           }
 275         end = ( (i > 0) && (' ' == bufr[i - 1]) ) ? (i - 1) : (i);
 276         c = mygetc( InFile );             /* Continue with next line.         */
 277         break;
 278
 279       default:                        /* All else are a valid name chars.   */
 280         if( isspace( c ) )              /* One space per whitespace region. */
 281           {
 282           bufr[end] = ' ';
 283           i = end + 1;
 284           c = EatWhitespace( InFile );
 285           }
 286         else                            /* All others copy verbatim.        */
 287           {
 288           bufr[i++] = c;
 289           end = i;
 290           c = mygetc( InFile );
 291           }
 292       }
 293     }
 294
 295   /* We arrive here if we've met the EOF before the closing bracket. */
 296   DEBUG(0, ("%s Unexpected EOF in the configuration file: %s\n", func, bufr ));
 297   return( False );
 298   } /* Section */
 299
 300 static BOOL Parameter( myFILE *InFile, BOOL (*pfunc)(const char *, const char *), int c )
 301   /* ------------------------------------------------------------------------ **
 302    * Scan a parameter name and value, and pass these two fields to pfunc().
 303    *
 304    *  Input:  InFile  - The input source.
 305    *          pfunc   - A pointer to the function that will be called to
 306    *                    process the parameter, once it has been scanned.
 307    *          c       - The first character of the parameter name, which
 308    *                    would have been read by Parse().  Unlike a comment
 309    *                    line or a section header, there is no lead-in
 310    *                    character that can be discarded.
 311    *
 312    *  Output: True if the parameter name and value were scanned and processed
 313    *          successfully, else False.
 314    *
 315    *  Notes:  This function is in two parts.  The first loop scans the
 316    *          parameter name.  Internal whitespace is compressed, and an
 317    *          equal sign (=) terminates the token.  Leading and trailing
 318    *          whitespace is discarded.  The second loop scans the parameter
 319    *          value.  When both have been successfully identified, they are
 320    *          passed to pfunc() for processing.
 321    *
 322    * ------------------------------------------------------------------------ **
 323    */
 324   {
 325   int   i       = 0;    /* Position within bufr. */
 326   int   end     = 0;    /* bufr[end] is current end-of-string. */
 327   int   vstart  = 0;    /* Starting position of the parameter value. */
 328   const char *func    = "params.c:Parameter() -";
 329
 330   /* Read the parameter name. */
 331   while( 0 == vstart )  /* Loop until we've found the start of the value. */
 332     {
 333
 334     if( i > (bSize - 2) )       /* Ensure there's space for next char.    */
 335       {
 336       char *tb;
 337
 338       tb = Realloc( bufr, bSize + BUFR_INC );
 339       if( NULL == tb )
 340         {
 341         DEBUG(0, ("%s Memory re-allocation failure.", func) );
 342         return( False );
 343         }
 344       bufr = tb;
 345       bSize += BUFR_INC;
 346       }
 347
 348     switch( c )
 349       {
 350       case '=':                 /* Equal sign marks end of param name. */
 351         if( 0 == end )              /* Don't allow an empty name.      */
 352           {
 353           DEBUG(0, ("%s Invalid parameter name in config. file.\n", func ));
 354           return( False );
 355           }
 356         bufr[end++] = '\0';         /* Mark end of string & advance.   */
 357         i       = end;              /* New string starts here.         */
 358         vstart  = end;              /* New string is parameter value.  */
 359         bufr[i] = '\0';             /* New string is nul, for now.     */
 360         break;
 361
 362       case '\n':                /* Find continuation char, else error. */
 363         i = Continuation( bufr, i );
 364         if( i < 0 )
 365           {
 366           bufr[end] = '\0';
 367           DEBUG(1,("%s Ignoring badly formed line in configuration file: %s\n",
 368                    func, bufr ));
 369           return( True );
 370           }
 371         end = ( (i > 0) && (' ' == bufr[i - 1]) ) ? (i - 1) : (i);
 372         c = mygetc( InFile );       /* Read past eoln.                   */
 373         break;
 374
 375       case '\0':                /* Shouldn't have EOF within param name. */
 376       case EOF:
 377         bufr[i] = '\0';
 378         DEBUG(1,("%s Unexpected end-of-file at: %s\n", func, bufr ));
 379         return( True );
 380
 381       default:
 382         if( isspace( c ) )     /* One ' ' per whitespace region.       */
 383           {
 384           bufr[end] = ' ';
 385           i = end + 1;
 386           c = EatWhitespace( InFile );
 387           }
 388         else                   /* All others verbatim.                 */
 389           {
 390           bufr[i++] = c;
 391           end = i;
 392           c = mygetc( InFile );
 393           }
 394       }
 395     }
 396
 397   /* Now parse the value. */
 398   c = EatWhitespace( InFile );  /* Again, trim leading whitespace. */
 399   while( (EOF !=c) && (c > 0) )
 400     {
 401
 402     if( i > (bSize - 2) )       /* Make sure there's enough room. */
 403       {
 404       char *tb;
 405
 406       tb = Realloc( bufr, bSize + BUFR_INC );
 407       if( NULL == tb )
 408         {
 409         DEBUG(0, ("%s Memory re-allocation failure.", func) );
 410         return( False );
 411         }
 412       bufr = tb;
 413       bSize += BUFR_INC;
 414       }
 415
 416     switch( c )
 417       {
 418       case '\r':              /* Explicitly remove '\r' because the older */
 419         c = mygetc( InFile );   /* version called fgets_slash() which also  */
 420         break;                /* removes them.                            */
 421
 422       case '\n':              /* Marks end of value unless there's a '\'. */
 423         i = Continuation( bufr, i );
 424         if( i < 0 )
 425           c = 0;
 426         else
 427           {
 428           for( end = i; (end >= 0) && isspace((int)bufr[end]); end-- )
 429             ;
 430           c = mygetc( InFile );
 431           }
 432         break;
 433
 434       default:               /* All others verbatim.  Note that spaces do */
 435         bufr[i++] = c;       /* not advance <end>.  This allows trimming  */
 436         if( !isspace( c ) )  /* of whitespace at the end of the line.     */
 437           end = i;
 438         c = mygetc( InFile );
 439         break;
 440       }
 441     }
 442   bufr[end] = '\0';          /* End of value. */
 443
 444   return( pfunc( bufr, &bufr[vstart] ) );   /* Pass name & value to pfunc().  */
 445   } /* Parameter */
 446
 447 static BOOL Parse( myFILE *InFile,
 448                    BOOL (*sfunc)(const char *),
 449                    BOOL (*pfunc)(const char *, const char *) )
 450   /* ------------------------------------------------------------------------ **
 451    * Scan & parse the input.
 452    *
 453    *  Input:  InFile  - Input source.
 454    *          sfunc   - Function to be called when a section name is scanned.
 455    *                    See Section().
 456    *          pfunc   - Function to be called when a parameter is scanned.
 457    *                    See Parameter().
 458    *
 459    *  Output: True if the file was successfully scanned, else False.
 460    *
 461    *  Notes:  The input can be viewed in terms of 'lines'.  There are four
 462    *          types of lines:
 463    *            Blank      - May contain whitespace, otherwise empty.
 464    *            Comment    - First non-whitespace character is a ';' or '#'.
 465    *                         The remainder of the line is ignored.
 466    *            Section    - First non-whitespace character is a '['.
 467    *            Parameter  - The default case.
 468    *
 469    * ------------------------------------------------------------------------ **
 470    */
 471   {
 472   int    c;
 473
 474   c = EatWhitespace( InFile );
 475   while( (EOF != c) && (c > 0) )
 476     {
 477     switch( c )
 478       {
 479       case '\n':                        /* Blank line. */
 480         c = EatWhitespace( InFile );
 481         break;
 482
 483       case ';':                         /* Comment line. */
 484       case '#':
 485         c = EatComment( InFile );
 486         break;
 487
 488       case '[':                         /* Section Header. */
 489         if( !Section( InFile, sfunc ) )
 490           return( False );
 491         c = EatWhitespace( InFile );
 492         break;
 493
 494       case '\\':                        /* Bogus backslash. */
 495         c = EatWhitespace( InFile );
 496         break;
 497
 498       default:                          /* Parameter line. */
 499         if( !Parameter( InFile, pfunc, c ) )
 500           return( False );
 501         c = EatWhitespace( InFile );
 502         break;
 503       }
 504     }
 505   return( True );
 506   } /* Parse */
 507
 508 static myFILE *OpenConfFile( const char *FileName )
 509   /* ------------------------------------------------------------------------ **
 510    * Open a configuration file.
 511    *
 512    *  Input:  FileName  - The pathname of the config file to be opened.
 513    *
 514    *  Output: A pointer of type (char **) to the lines of the file
 515    *
 516    * ------------------------------------------------------------------------ **
 517    */
 518   {
 519   const char *func = "params.c:OpenConfFile() -";
 520   extern BOOL in_client;
 521   int lvl = in_client?1:0;
 522   myFILE *ret;
 523
 524   ret = (myFILE *)malloc(sizeof(*ret));
 525   if (!ret) return NULL;
 526
 527   ret->buf = file_load(FileName, &ret->size);
 528   if( NULL == ret->buf )
 529     {
 530     DEBUG( lvl,
 531       ("%s Unable to open configuration file \"%s\":\n\t%s\n",
 532       func, FileName, strerror(errno)) );
 533     SAFE_FREE(ret);
 534     return NULL;
 535     }
 536
 537   ret->p = ret->buf;
 538   return( ret );
 539   } /* OpenConfFile */
 540
 541 BOOL pm_process( const char *FileName,
 542                  BOOL (*sfunc)(const char *),
 543                  BOOL (*pfunc)(const char *, const char *) )
 544   /* ------------------------------------------------------------------------ **
 545    * Process the named parameter file.
 546    *
 547    *  Input:  FileName  - The pathname of the parameter file to be opened.
 548    *          sfunc     - A pointer to a function that will be called when
 549    *                      a section name is discovered.
 550    *          pfunc     - A pointer to a function that will be called when
 551    *                      a parameter name and value are discovered.
 552    *
 553    *  Output: TRUE if the file was successfully parsed, else FALSE.
 554    *
 555    * ------------------------------------------------------------------------ **
 556    */
 557   {
 558   int   result;
 559   myFILE *InFile;
 560   const char *func = "params.c:pm_process() -";
 561
 562   InFile = OpenConfFile( FileName );          /* Open the config file. */
 563   if( NULL == InFile )
 564     return( False );
 565
 566   DEBUG( 3, ("%s Processing configuration file \"%s\"\n", func, FileName) );
 567
 568   if( NULL != bufr )                          /* If we already have a buffer */
 569     result = Parse( InFile, sfunc, pfunc );   /* (recursive call), then just */
 570                                               /* use it.                     */
 571
 572   else                                        /* If we don't have a buffer   */
 573     {                                         /* allocate one, then parse,   */
 574     bSize = BUFR_INC;                         /* then free.                  */
 575     bufr = (char *)malloc( bSize );
 576     if( NULL == bufr )
 577       {
 578       DEBUG(0,("%s memory allocation failure.\n", func));
 579       myfile_close(InFile);
 580       return( False );
 581       }
 582     result = Parse( InFile, sfunc, pfunc );
 583     SAFE_FREE( bufr );
 584     bufr  = NULL;
 585     bSize = 0;
 586     }
 587
 588   myfile_close(InFile);
 589
 590   if( !result )                               /* Generic failure. */
 591     {
 592     DEBUG(0,("%s Failed.  Error returned from params.c:parse().\n", func));
 593     return( False );
 594     }
 595
 596   return( True );                             /* Generic success. */
 597   } /* pm_process */
 598
 599 /* -------------------------------------------------------------------------- */