params.c

   1 /* This modules is based on the params.c module from Samba, written by Karl Auer
   2    and much modifed by Christopher Hertel. */
   3
   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 along
  16  * with this program; if not, visit the http://fsf.org website.
  17  */
  18
  19 /* -------------------------------------------------------------------------- **
  20  *
  21  * Module name: params
  22  *
  23  * -------------------------------------------------------------------------- **
  24  *
  25  *  This module performs lexical analysis and initial parsing of a
  26  *  Windows-like parameter file.  It recognizes and handles four token
  27  *  types:  section-name, parameter-name, parameter-value, and
  28  *  end-of-file.  Comments and line continuation are handled
  29  *  internally.
  30  *
  31  *  The entry point to the module is function pm_process().  This
  32  *  function opens the source file, calls the Parse() function to parse
  33  *  the input, and then closes the file when either the EOF is reached
  34  *  or a fatal error is encountered.
  35  *
  36  *  A sample parameter file might look like this:
  37  *
  38  *  [section one]
  39  *  parameter one = value string
  40  *  parameter two = another value
  41  *  [section two]
  42  *  new parameter = some value or t'other
  43  *
  44  *  The parameter file is divided into sections by section headers:
  45  *  section names enclosed in square brackets (eg. [section one]).
  46  *  Each section contains parameter lines, each of which consist of a
  47  *  parameter name and value delimited by an equal sign.  Roughly, the
  48  *  syntax is:
  49  *
  50  *    <file>            :==  { <section> } EOF
  51  *
  52  *    <section>         :==  <section header> { <parameter line> }
  53  *
  54  *    <section header>  :==  '[' NAME ']'
  55  *
  56  *    <parameter line>  :==  NAME '=' VALUE '\n'
  57  *
  58  *  Blank lines and comment lines are ignored.  Comment lines are lines
  59  *  beginning with either a semicolon (';') or a pound sign ('#').
  60  *
  61  *  All whitespace in section names and parameter names is compressed
  62  *  to single spaces.  Leading and trailing whitespace is stipped from
  63  *  both names and values.
  64  *
  65  *  Only the first equals sign in a parameter line is significant.
  66  *  Parameter values may contain equals signs, square brackets and
  67  *  semicolons.  Internal whitespace is retained in parameter values,
  68  *  with the exception of the '\r' character, which is stripped for
  69  *  historic reasons.  Parameter names may not start with a left square
  70  *  bracket, an equal sign, a pound sign, or a semicolon, because these
  71  *  are used to identify other tokens.
  72  *
  73  * -------------------------------------------------------------------------- **
  74  */
  75
  76 #include "rsync.h"
  77 #include "ifuncs.h"
  78 #include "itypes.h"
  79
  80 /* -------------------------------------------------------------------------- **
  81  * Constants...
  82  */
  83
  84 #define BUFR_INC 1024
  85
  86
  87 /* -------------------------------------------------------------------------- **
  88  * Variables...
  89  *
  90  *  bufr        - pointer to a global buffer.  This is probably a kludge,
  91  *                but it was the nicest kludge I could think of (for now).
  92  *  bSize       - The size of the global buffer <bufr>.
  93  */
  94
  95 static char *bufr  = NULL;
  96 static int   bSize = 0;
  97 static BOOL  (*the_sfunc)(char *);
  98 static BOOL  (*the_pfunc)(char *, char *);
  99
 100 /* -------------------------------------------------------------------------- **
 101  * Functions...
 102  */
 103
 104 static int EatWhitespace( FILE *InFile )
 105   /* ------------------------------------------------------------------------ **
 106    * Scan past whitespace (see ctype(3C)) and return the first non-whitespace
 107    * character, or newline, or EOF.
 108    *
 109    *  Input:  InFile  - Input source.
 110    *
 111    *  Output: The next non-whitespace character in the input stream.
 112    *
 113    *  Notes:  Because the config files use a line-oriented grammar, we
 114    *          explicitly exclude the newline character from the list of
 115    *          whitespace characters.
 116    *        - Note that both EOF (-1) and the nul character ('\0') are
 117    *          considered end-of-file markers.
 118    *
 119    * ------------------------------------------------------------------------ **
 120    */
 121   {
 122   int c;
 123
 124   for( c = getc( InFile ); isspace( c ) && ('\n' != c); c = getc( InFile ) )
 125     ;
 126   return( c );
 127   } /* EatWhitespace */
 128
 129 static int EatComment( FILE *InFile )
 130   /* ------------------------------------------------------------------------ **
 131    * Scan to the end of a comment.
 132    *
 133    *  Input:  InFile  - Input source.
 134    *
 135    *  Output: The character that marks the end of the comment.  Normally,
 136    *          this will be a newline, but it *might* be an EOF.
 137    *
 138    *  Notes:  Because the config files use a line-oriented grammar, we
 139    *          explicitly exclude the newline character from the list of
 140    *          whitespace characters.
 141    *        - Note that both EOF (-1) and the nul character ('\0') are
 142    *          considered end-of-file markers.
 143    *
 144    * ------------------------------------------------------------------------ **
 145    */
 146   {
 147   int c;
 148
 149   for( c = getc( InFile ); ('\n'!=c) && (EOF!=c) && (c>0); c = getc( InFile ) )
 150     ;
 151   return( c );
 152   } /* EatComment */
 153
 154 static int Continuation( char *line, int pos )
 155   /* ------------------------------------------------------------------------ **
 156    * Scan backards within a string to discover if the last non-whitespace
 157    * character is a line-continuation character ('\\').
 158    *
 159    *  Input:  line  - A pointer to a buffer containing the string to be
 160    *                  scanned.
 161    *          pos   - This is taken to be the offset of the end of the
 162    *                  string.  This position is *not* scanned.
 163    *
 164    *  Output: The offset of the '\\' character if it was found, or -1 to
 165    *          indicate that it was not.
 166    *
 167    * ------------------------------------------------------------------------ **
 168    */
 169   {
 170   pos--;
 171   while( pos >= 0 && isSpace(line + pos) )
 172      pos--;
 173
 174   return( ((pos >= 0) && ('\\' == line[pos])) ? pos : -1 );
 175   } /* Continuation */
 176
 177
 178 static BOOL Section( FILE *InFile, BOOL (*sfunc)(char *) )
 179   /* ------------------------------------------------------------------------ **
 180    * Scan a section name, and pass the name to function sfunc().
 181    *
 182    *  Input:  InFile  - Input source.
 183    *          sfunc   - Pointer to the function to be called if the section
 184    *                    name is successfully read.
 185    *
 186    *  Output: True if the section name was read and True was returned from
 187    *          <sfunc>.  False if <sfunc> failed or if a lexical error was
 188    *          encountered.
 189    *
 190    * ------------------------------------------------------------------------ **
 191    */
 192   {
 193   int   c;
 194   int   i;
 195   int   end;
 196   char *func  = "params.c:Section() -";
 197
 198   i = 0;      /* <i> is the offset of the next free byte in bufr[] and  */
 199   end = 0;    /* <end> is the current "end of string" offset.  In most  */
 200               /* cases these will be the same, but if the last          */
 201               /* character written to bufr[] is a space, then <end>     */
 202               /* will be one less than <i>.                             */
 203
 204   c = EatWhitespace( InFile );    /* We've already got the '['.  Scan */
 205                                   /* past initial white space.        */
 206
 207   while( (EOF != c) && (c > 0) )
 208     {
 209
 210     /* Check that the buffer is big enough for the next character. */
 211     if( i > (bSize - 2) )
 212       {
 213       bSize += BUFR_INC;
 214       bufr   = realloc_array( bufr, char, bSize );
 215       if( NULL == bufr )
 216         {
 217         rprintf(FLOG, "%s Memory re-allocation failure.", func);
 218         return( False );
 219         }
 220       }
 221
 222     /* Handle a single character. */
 223     switch( c )
 224       {
 225       case ']':                       /* Found the closing bracket.         */
 226         bufr[end] = '\0';
 227         if( 0 == end )                  /* Don't allow an empty name.       */
 228           {
 229           rprintf(FLOG, "%s Empty section name in config file.\n", func );
 230           return( False );
 231           }
 232         if( !sfunc( bufr ) )            /* Got a valid name.  Deal with it. */
 233           return( False );
 234         (void)EatComment( InFile );     /* Finish off the line.             */
 235         return( True );
 236
 237       case '\n':                      /* Got newline before closing ']'.    */
 238         i = Continuation( bufr, i );    /* Check for line continuation.     */
 239         if( i < 0 )
 240           {
 241           bufr[end] = '\0';
 242           rprintf(FLOG, "%s Badly formed line in config file: %s\n",
 243                    func, bufr );
 244           return( False );
 245           }
 246         end = ( (i > 0) && (' ' == bufr[i - 1]) ) ? (i - 1) : (i);
 247         c = getc( InFile );             /* Continue with next line.         */
 248         break;
 249
 250       default:                        /* All else are a valid name chars.   */
 251         if( isspace( c ) )              /* One space per whitespace region. */
 252           {
 253           bufr[end] = ' ';
 254           i = end + 1;
 255           c = EatWhitespace( InFile );
 256           }
 257         else                            /* All others copy verbatim.        */
 258           {
 259           bufr[i++] = c;
 260           end = i;
 261           c = getc( InFile );
 262           }
 263       }
 264     }
 265
 266   /* We arrive here if we've met the EOF before the closing bracket. */
 267   rprintf(FLOG, "%s Unexpected EOF in the config file: %s\n", func, bufr );
 268   return( False );
 269   } /* Section */
 270
 271 static BOOL Parameter( FILE *InFile, BOOL (*pfunc)(char *, char *), int c )
 272   /* ------------------------------------------------------------------------ **
 273    * Scan a parameter name and value, and pass these two fields to pfunc().
 274    *
 275    *  Input:  InFile  - The input source.
 276    *          pfunc   - A pointer to the function that will be called to
 277    *                    process the parameter, once it has been scanned.
 278    *          c       - The first character of the parameter name, which
 279    *                    would have been read by Parse().  Unlike a comment
 280    *                    line or a section header, there is no lead-in
 281    *                    character that can be discarded.
 282    *
 283    *  Output: True if the parameter name and value were scanned and processed
 284    *          successfully, else False.
 285    *
 286    *  Notes:  This function is in two parts.  The first loop scans the
 287    *          parameter name.  Internal whitespace is compressed, and an
 288    *          equal sign (=) terminates the token.  Leading and trailing
 289    *          whitespace is discarded.  The second loop scans the parameter
 290    *          value.  When both have been successfully identified, they are
 291    *          passed to pfunc() for processing.
 292    *
 293    * ------------------------------------------------------------------------ **
 294    */
 295   {
 296   int   i       = 0;    /* Position within bufr. */
 297   int   end     = 0;    /* bufr[end] is current end-of-string. */
 298   int   vstart  = 0;    /* Starting position of the parameter value. */
 299   char *func    = "params.c:Parameter() -";
 300
 301   /* Read the parameter name. */
 302   while( 0 == vstart )  /* Loop until we've found the start of the value. */
 303     {
 304
 305     if( i > (bSize - 2) )       /* Ensure there's space for next char.    */
 306       {
 307       bSize += BUFR_INC;
 308       bufr   = realloc_array( bufr, char, bSize );
 309       if( NULL == bufr )
 310         {
 311         rprintf(FLOG, "%s Memory re-allocation failure.", func) ;
 312         return( False );
 313         }
 314       }
 315
 316     switch( c )
 317       {
 318       case '=':                 /* Equal sign marks end of param name. */
 319         if( 0 == end )              /* Don't allow an empty name.      */
 320           {
 321           rprintf(FLOG, "%s Invalid parameter name in config file.\n", func );
 322           return( False );
 323           }
 324         bufr[end++] = '\0';         /* Mark end of string & advance.   */
 325         i = vstart = end;           /* New string starts here.         */
 326         c = EatWhitespace(InFile);
 327         break;
 328
 329       case '\n':                /* Find continuation char, else error. */
 330         i = Continuation( bufr, i );
 331         if( i < 0 )
 332           {
 333           bufr[end] = '\0';
 334           rprintf(FLOG, "%s Ignoring badly formed line in config file: %s\n",
 335                    func, bufr );
 336           return( True );
 337           }
 338         end = ( (i > 0) && (' ' == bufr[i - 1]) ) ? (i - 1) : (i);
 339         c = getc( InFile );       /* Read past eoln.                   */
 340         break;
 341
 342       case '\0':                /* Shouldn't have EOF within param name. */
 343       case EOF:
 344         bufr[i] = '\0';
 345         rprintf(FLOG, "%s Unexpected end-of-file at: %s\n", func, bufr );
 346         return( True );
 347
 348       case ' ':
 349       case '\t':
 350         /* A directive divides at the first space or tab. */
 351         if (*bufr == '&') {
 352           bufr[end++] = '\0';
 353           i = vstart = end;
 354           c = EatWhitespace(InFile);
 355           if (c == '=')
 356             c = EatWhitespace(InFile);
 357           break;
 358         }
 359         /* FALL THROUGH */
 360
 361       default:
 362         if( isspace( c ) )     /* One ' ' per whitespace region.       */
 363           {
 364           bufr[end] = ' ';
 365           i = end + 1;
 366           c = EatWhitespace( InFile );
 367           }
 368         else                   /* All others verbatim.                 */
 369           {
 370           bufr[i++] = c;
 371           end = i;
 372           c = getc( InFile );
 373           }
 374       }
 375     }
 376
 377   /* Now parse the value. */
 378   while( (EOF !=c) && (c > 0) )
 379     {
 380
 381     if( i > (bSize - 2) )       /* Make sure there's enough room. */
 382       {
 383       bSize += BUFR_INC;
 384       bufr   = realloc_array( bufr, char, bSize );
 385       if( NULL == bufr )
 386         {
 387         rprintf(FLOG, "%s Memory re-allocation failure.", func) ;
 388         return( False );
 389         }
 390       }
 391
 392     switch( c )
 393       {
 394       case '\r':              /* Explicitly remove '\r' because the older */
 395         c = getc( InFile );   /* version called fgets_slash() which also  */
 396         break;                /* removes them.                            */
 397
 398       case '\n':              /* Marks end of value unless there's a '\'. */
 399         i = Continuation( bufr, i );
 400         if( i < 0 )
 401           c = 0;
 402         else
 403           {
 404           for( end = i; end >= 0 && isSpace(bufr + end); end-- )
 405             ;
 406           c = getc( InFile );
 407           }
 408         break;
 409
 410       default:               /* All others verbatim.  Note that spaces do */
 411         bufr[i++] = c;       /* not advance <end>.  This allows trimming  */
 412         if( !isspace( c ) )  /* of whitespace at the end of the line.     */
 413           end = i;
 414         c = getc( InFile );
 415         break;
 416       }
 417     }
 418   bufr[end] = '\0';          /* End of value. */
 419
 420   return( pfunc( bufr, &bufr[vstart] ) );   /* Pass name & value to pfunc().  */
 421   } /* Parameter */
 422
 423 static int name_cmp(const void *n1, const void *n2)
 424 {
 425     return strcmp(*(char * const *)n1, *(char * const *)n2);
 426 }
 427
 428 static int include_config(char *include, int manage_globals)
 429 {
 430     STRUCT_STAT sb;
 431     int ret;
 432
 433     if (do_stat(include, &sb) < 0) {
 434         rsyserr(FLOG, errno, "unable to stat config file \"%s\"", include);
 435         return 0;
 436     }
 437
 438     if (S_ISREG(sb.st_mode)) {
 439         if (manage_globals && the_sfunc)
 440             the_sfunc("]push");
 441         ret = pm_process(include, the_sfunc, the_pfunc);
 442         if (manage_globals && the_sfunc)
 443             the_sfunc("]pop");
 444     } else if (S_ISDIR(sb.st_mode)) {
 445         char buf[MAXPATHLEN], **bpp;
 446         item_list conf_list;
 447         struct dirent *di;
 448         size_t j;
 449         DIR *d;
 450
 451         if (!(d = opendir(include))) {
 452             rsyserr(FLOG, errno, "unable to open config dir \"%s\"", include);
 453             return 0;
 454         }
 455
 456         memset(&conf_list, 0, sizeof conf_list);
 457
 458         while ((di = readdir(d)) != NULL) {
 459             char *dname = d_name(di);
 460             if (!wildmatch("*.conf", dname))
 461                 continue;
 462             bpp = EXPAND_ITEM_LIST(&conf_list, char *, 32);
 463             pathjoin(buf, sizeof buf, include, dname);
 464             *bpp = strdup(buf);
 465         }
 466         closedir(d);
 467
 468         if (!(bpp = conf_list.items))
 469             return 1;
 470
 471         if (conf_list.count > 1)
 472             qsort(bpp, conf_list.count, sizeof (char *), name_cmp);
 473
 474         for (j = 0, ret = 1; j < conf_list.count; j++) {
 475             if (manage_globals && the_sfunc)
 476                 the_sfunc(j == 0 ? "]push" : "]reset");
 477             if ((ret = pm_process(bpp[j], the_sfunc, the_pfunc)) != 1)
 478                 break;
 479         }
 480
 481         if (manage_globals && the_sfunc)
 482             the_sfunc("]pop");
 483
 484         for (j = 0; j < conf_list.count; j++)
 485             free(bpp[j]);
 486         free(bpp);
 487     } else
 488         ret = 0;
 489
 490     return ret;
 491 }
 492
 493 static int parse_directives(char *name, char *val)
 494 {
 495     if (strcasecmp(name, "&include") == 0)
 496         return include_config(val, 1);
 497     if (strcasecmp(name, "&merge") == 0)
 498         return include_config(val, 0);
 499     rprintf(FLOG, "Unknown directive: %s.\n", name);
 500     return 0;
 501 }
 502
 503 static int Parse( FILE *InFile,
 504                    BOOL (*sfunc)(char *),
 505                    BOOL (*pfunc)(char *, char *) )
 506   /* ------------------------------------------------------------------------ **
 507    * Scan & parse the input.
 508    *
 509    *  Input:  InFile  - Input source.
 510    *          sfunc   - Function to be called when a section name is scanned.
 511    *                    See Section().
 512    *          pfunc   - Function to be called when a parameter is scanned.
 513    *                    See Parameter().
 514    *
 515    *  Output: 1 if the file was successfully scanned, 2 if the file was
 516    *  scanned until a section header with no section function, else 0.
 517    *
 518    *  Notes:  The input can be viewed in terms of 'lines'.  There are four
 519    *          types of lines:
 520    *            Blank      - May contain whitespace, otherwise empty.
 521    *            Comment    - First non-whitespace character is a ';' or '#'.
 522    *                         The remainder of the line is ignored.
 523    *            Section    - First non-whitespace character is a '['.
 524    *            Parameter  - The default case.
 525    *
 526    * ------------------------------------------------------------------------ **
 527    */
 528   {
 529   int    c;
 530
 531   c = EatWhitespace( InFile );
 532   while( (EOF != c) && (c > 0) )
 533     {
 534     switch( c )
 535       {
 536       case '\n':                        /* Blank line. */
 537         c = EatWhitespace( InFile );
 538         break;
 539
 540       case ';':                         /* Comment line. */
 541       case '#':
 542         c = EatComment( InFile );
 543         break;
 544
 545       case '[':                         /* Section Header. */
 546         if (!sfunc)
 547           return 2;
 548         if( !Section( InFile, sfunc ) )
 549           return 0;
 550         c = EatWhitespace( InFile );
 551         break;
 552
 553       case '\\':                        /* Bogus backslash. */
 554         c = EatWhitespace( InFile );
 555         break;
 556
 557       case '&':                         /* Handle directives */
 558         the_sfunc = sfunc;
 559         the_pfunc = pfunc;
 560         c = Parameter( InFile, parse_directives, c );
 561         if (c != 1)
 562           return c;
 563         c = EatWhitespace( InFile );
 564         break;
 565
 566       default:                          /* Parameter line. */
 567         if( !Parameter( InFile, pfunc, c ) )
 568           return 0;
 569         c = EatWhitespace( InFile );
 570         break;
 571       }
 572     }
 573   return 1;
 574   } /* Parse */
 575
 576 static FILE *OpenConfFile( char *FileName )
 577   /* ------------------------------------------------------------------------ **
 578    * Open a config file.
 579    *
 580    *  Input:  FileName  - The pathname of the config file to be opened.
 581    *
 582    *  Output: A pointer of type (FILE *) to the opened file, or NULL if the
 583    *          file could not be opened.
 584    *
 585    * ------------------------------------------------------------------------ **
 586    */
 587   {
 588   FILE *OpenedFile;
 589   char *func = "params.c:OpenConfFile() -";
 590
 591   if( NULL == FileName || 0 == *FileName )
 592     {
 593     rprintf(FLOG, "%s No config filename specified.\n", func);
 594     return( NULL );
 595     }
 596
 597   OpenedFile = fopen( FileName, "r" );
 598   if( NULL == OpenedFile )
 599     {
 600     rsyserr(FLOG, errno, "unable to open config file \"%s\"",
 601             FileName);
 602     }
 603
 604   return( OpenedFile );
 605   } /* OpenConfFile */
 606
 607 int pm_process( char *FileName,
 608                  BOOL (*sfunc)(char *),
 609                  BOOL (*pfunc)(char *, char *) )
 610   /* ------------------------------------------------------------------------ **
 611    * Process the named parameter file.
 612    *
 613    *  Input:  FileName  - The pathname of the parameter file to be opened.
 614    *          sfunc     - A pointer to a function that will be called when
 615    *                      a section name is discovered.
 616    *          pfunc     - A pointer to a function that will be called when
 617    *                      a parameter name and value are discovered.
 618    *
 619    *  Output: 1 if the file was successfully parsed, 2 if parsing ended at a
 620    *  section header w/o a section function, else 0.
 621    *
 622    * ------------------------------------------------------------------------ **
 623    */
 624   {
 625   int   result;
 626   FILE *InFile;
 627   char *func = "params.c:pm_process() -";
 628
 629   InFile = OpenConfFile( FileName );          /* Open the config file. */
 630   if( NULL == InFile )
 631     return( False );
 632
 633   if( NULL != bufr )                          /* If we already have a buffer */
 634     result = Parse( InFile, sfunc, pfunc );   /* (recursive call), then just */
 635                                               /* use it.                     */
 636
 637   else                                        /* If we don't have a buffer   */
 638     {                                         /* allocate one, then parse,   */
 639     bSize = BUFR_INC;                         /* then free.                  */
 640     bufr = new_array( char, bSize );
 641     if( NULL == bufr )
 642       {
 643       rprintf(FLOG, "%s memory allocation failure.\n", func);
 644       fclose(InFile);
 645       return( False );
 646       }
 647     result = Parse( InFile, sfunc, pfunc );
 648     free( bufr );
 649     bufr  = NULL;
 650     bSize = 0;
 651     }
 652
 653   fclose(InFile);
 654
 655   if( !result )                               /* Generic failure. */
 656     {
 657     rprintf(FLOG, "%s Failed.  Error returned from params.c:parse().\n", func);
 658     return 0;
 659     }
 660
 661   return result;
 662   } /* pm_process */
 663
 664 /* -------------------------------------------------------------------------- */
 665