mdw@git.distorted.org.uk Git - become/blob - src/parser.y

   1 /* -*-c-*-
   2  *
   3  * $Id: parser.y,v 1.5 1998/01/12 16:46:22 mdw Exp $
   4  *
   5  * Parser for `become.conf' files
   6  *
   7  * (c) 1998 EBI
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of `become'
  13  *
  14  * `Become' is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * `Become' is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with `become'; if not, write to the Free Software Foundation,
  26  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 /*----- Revision history --------------------------------------------------*
  30  *
  31  * $Log: parser.y,v $
  32  * Revision 1.5  1998/01/12 16:46:22  mdw
  33  * Fix copyright date.
  34  *
  35  * Revision 1.4  1997/09/17  10:26:52  mdw
  36  * Use rewritten class handler.  Makes the expression parsers considerably
  37  * simpler.
  38  *
  39  * Revision 1.3  1997/09/09 18:17:06  mdw
  40  * Allow default port to be given as a service name or port number.
  41  *
  42  * Revision 1.2  1997/08/04 10:24:24  mdw
  43  * Sources placed under CVS control.
  44  *
  45  * Revision 1.1  1997/07/21  13:47:45  mdw
  46  * Initial revision
  47  *
  48  */
  49
  50 /*----- Header files ------------------------------------------------------*/
  51 %{
  52
  53 /* --- ANSI headers --- */
  54
  55 #include <stdio.h>
  56 #include <stdlib.h>
  57 #include <string.h>
  58
  59 /* --- Unix headers --- */
  60
  61 #include <sys/types.h>
  62 #include <sys/socket.h>
  63
  64 #include <netinet/in.h>
  65
  66 #include <arpa/inet.h>
  67
  68 #include <netdb.h>
  69 #include <pwd.h>
  70 #include <unistd.h>
  71
  72 /* --- Local headers --- */
  73
  74 #include "class.h"
  75 #include "daemon.h"
  76 #include "lexer.h"
  77 #include "name.h"
  78 #include "rule.h"
  79 #include "sym.h"
  80 #include "userdb.h"
  81 #include "utils.h"
  82
  83 %}
  84 /*----- Stack type --------------------------------------------------------*/
  85
  86 %union {
  87   long i;
  88   char *s;
  89   name *n;
  90   class_node *c;
  91 }
  92
  93 /*----- Token and rule declarations ---------------------------------------*/
  94
  95 /* --- Tokens --- */
  96
  97 %token BADTOKEN
  98 %token USER
  99 %token COMMAND
 100 %token HOST
 101 %token ALLOW
 102 %token PORT
 103 %token KEYFILE
 104 %token <i> INT
 105 %token <s> WORD
 106 %token <s> STRING
 107 %token ARROW
 108
 109 %left ','
 110 %left '-'
 111 %left '|'
 112 %left '&'
 113
 114 /* --- Rules --- */
 115
 116 %type <c> user_class command_class host_class
 117 %type <c> user_class_opt command_class_opt host_class_opt
 118 %type <n> name
 119
 120 /*----- Error reporting ---------------------------------------------------*/
 121 %{
 122
 123 #define YYDEBUG 1
 124 #define YYERROR_VERBOSE
 125
 126 /* --- @yyprint@ --- *
 127  *
 128  * Arguments:   @FILE *fp@ = pointer to stream to write on
 129  *              @int type@ = pointer to token type
 130  *              @YYSTYPE v@ = token value
 131  *
 132  * Returns:     ---
 133  *
 134  * Use:         Displays the semantic value of a token.
 135  */
 136
 137 #define YYPRINT(fp, type, value) yyprint(fp, type, value)
 138
 139 static void yyprint(FILE *fp, int type, YYSTYPE v)
 140 {
 141   switch (type) {
 142     case INT:
 143       fprintf(fp, " %li", v.i);
 144       break;
 145     case WORD:
 146     case STRING:
 147       fprintf(fp, " `%s'", v.s);
 148       break;
 149   }
 150 }
 151
 152 /* --- @yyerror@ --- *
 153  *
 154  * Arguments:   @const char *msg@ = pointer to error message
 155  *
 156  * Returns:     ---
 157  *
 158  * Use:         Reports parse errors.
 159  */
 160
 161 static void yyerror(const char *msg)
 162 {
 163   moan("%s at line %i", msg, lex_line);
 164 }
 165
 166 %}
 167 %%
 168 /*----- The actual grammar ------------------------------------------------*/
 169
 170 /* --- Simple driver things --- */
 171
 172 file            : /* empty */
 173                 | file statement
 174                 ;
 175
 176 statement       : user_spec
 177                 | command_spec
 178                 | host_spec
 179                 | allow_spec
 180                 | port_spec
 181                 | key_spec
 182                 | error ';'
 183                 ;
 184
 185 /* --- Main statement types --- */
 186
 187 user_spec       : USER name '=' user_class ';' {
 188                           if ($2->c)
 189                             class_dec($2->c);
 190                           $2->c = $4;
 191                         }
 192                 ;
 193
 194 command_spec    : COMMAND name '=' command_class ';' {
 195                           if ($2->c)
 196                             class_dec($2->c);
 197                           $2->c = $4;
 198                         }
 199                 ;
 200
 201 host_spec       : HOST name '=' host_class ';' {
 202                           if ($2->c)
 203                             class_dec($2->c);
 204                           $2->c = $4;
 205                         }
 206                 ;
 207
 208 port_spec       : PORT STRING ';' {
 209                           struct servent *s = getservbyname($2, "udp");
 210                           if (!s) {
 211                             moan("unknown service `%s' at line %i",
 212                                  $2, lex_line);
 213                             YYERROR;
 214                           }
 215                           daemon_usePort(s->s_port);
 216                         }
 217                 | PORT INT ';' { daemon_usePort(htons($2)); }
 218                 ;
 219
 220 key_spec        : KEYFILE STRING ';' { daemon_readKey($2); }
 221
 222 /* --- Parsing allow specifications --- */
 223
 224 allow_spec      : ALLOW host_class_opt user_class ARROW
 225                    user_class_opt command_class_opt ';' {
 226                           rule_add($2, $3, $5, $6);
 227                         }
 228
 229 host_class_opt  : /* empty */ { $$ = class_all; }
 230                 | '[' host_class ']' { $$ = $2; }
 231                 ;
 232
 233 user_class_opt  : /* empty */ { $$ = class_all; }
 234                 | user_class { $$ = $1; }
 235                 ;
 236
 237 command_class_opt : /* empty */ { $$ = class_all; }
 238                 | ':' command_class { $$ = $2; }
 239                 ;
 240
 241 /* --- Names get translated into symbols quickly --- */
 242
 243 name            : WORD  {
 244                           unsigned f;
 245                           name *n = name_find($1, 1, &f);
 246                           if (!f)
 247                             n->c = 0;
 248                           $$ = n;
 249                         }
 250
 251 /*----- Various class expression types ------------------------------------*
 252  *
 253  * Unfortunately, all these need to handle token types slightly differently
 254  * and I can't be bothered to remember the current state.
 255  */
 256
 257 /* --- User class expressions --- */
 258
 259 user_class      : user_class ',' user_class {
 260                           if (($$ = class_union($1, $3)) == 0) {
 261                             yyerror("type mismatch");
 262                             YYERROR;
 263                           }
 264                         }
 265                 | user_class '-' user_class {
 266                           if (($$ = class_diff($1, $3)) == 0) {
 267                             yyerror("type mismatch");
 268                             YYERROR;
 269                           }
 270                         }
 271                 | user_class '&' user_class {
 272                           if (($$ = class_isect($1, $3)) == 0) {
 273                             yyerror("type mismatch");
 274                             YYERROR;
 275                           }
 276                         }
 277                 | user_class '|' user_class {
 278                           if (($$ = class_union($1, $3)) == 0) {
 279                             yyerror("type mismatch");
 280                             YYERROR;
 281                           }
 282                         }
 283                 | INT   { $$ = class_fromUser(clType_user, $1); }
 284                 | STRING {
 285                           struct passwd *pw;
 286                           if ((pw = userdb_userByName($1)) == 0) {
 287                             moan("user `%s' not known at line %i",
 288                                  $1, lex_line);
 289                             YYERROR;
 290                           } else
 291                             $$ = class_fromUser(clType_user, pw->pw_uid);
 292                         }
 293                 | WORD  {
 294                           name *n = name_find($1, 0, 0);
 295                           if (!n || !n->c) {
 296                             moan("class `%s' not found at line %i",
 297                                  $1, lex_line);
 298                             YYERROR;
 299                           } else if (~n->c->type & clType_user) {
 300                             yyerror("type mismatch");
 301                             YYERROR;
 302                           } else {
 303                             $$ = n->c;
 304                             class_inc(n->c);
 305                           }
 306                         }
 307                 | '(' user_class ')' { $$ = $2; }
 308                 ;
 309
 310 /* --- Command class expressions --- */
 311
 312 command_class   : command_class ',' command_class {
 313                           if (($$ = class_union($1, $3)) == 0) {
 314                             yyerror("type mismatch");
 315                             YYERROR;
 316                           }
 317                         }
 318                 | command_class '-' command_class {
 319                           if (($$ = class_diff($1, $3)) == 0) {
 320                             yyerror("type mismatch");
 321                             YYERROR;
 322                           }
 323                         }
 324                 | command_class '&' command_class {
 325                           if (($$ = class_isect($1, $3)) == 0) {
 326                             yyerror("type mismatch");
 327                             YYERROR;
 328                           }
 329                         }
 330                 | command_class '|' command_class {
 331                           if (($$ = class_union($1, $3)) == 0) {
 332                             yyerror("type mismatch");
 333                             YYERROR;
 334                           }
 335                         }
 336                 | STRING { $$ = class_fromString(clType_command, $1); }
 337                 | WORD  {
 338                           name *n = name_find($1, 0, 0);
 339                           if (!n || !n->c) {
 340                             moan("class `%s' not found at line %i",
 341                                  $1, lex_line);
 342                             YYERROR;
 343                           } else if (~n->c->type & clType_command) {
 344                             yyerror("type mismatch");
 345                             YYERROR;
 346                           } else {
 347                             $$ = n->c;
 348                             class_inc(n->c);
 349                           }
 350                         }
 351                 | '(' command_class ')' { $$ = $2; }
 352                 ;
 353
 354 /* --- Host class expressions --- */
 355
 356 host_class      : host_class ',' host_class {
 357                           if (($$ = class_union($1, $3)) == 0) {
 358                             yyerror("type mismatch");
 359                             YYERROR;
 360                           }
 361                         }
 362                 | host_class '-' host_class {
 363                           if (($$ = class_diff($1, $3)) == 0) {
 364                             yyerror("type mismatch");
 365                             YYERROR;
 366                           }
 367                         }
 368                 | host_class '&' host_class {
 369                           if (($$ = class_isect($1, $3)) == 0) {
 370                             yyerror("type mismatch");
 371                             YYERROR;
 372                           }
 373                         }
 374                 | host_class '|' host_class {
 375                           if (($$ = class_union($1, $3)) == 0) {
 376                             yyerror("type mismatch");
 377                             YYERROR;
 378                           }
 379                         }
 380                 | STRING { $$ = class_fromString(clType_host, $1); }
 381                 | WORD  {
 382                           name *n = name_find($1, 0, 0);
 383                           if (!n || !n->c) {
 384                             moan("class `%s' not found at line %i",
 385                                  $1, lex_line);
 386                             YYERROR;
 387                           } else if (~n->c->type & clType_host) {
 388                             yyerror("type mismatch");
 389                             YYERROR;
 390                           } else {
 391                             $$ = n->c;
 392                             class_inc(n->c);
 393                           }
 394                         }
 395                 | '(' host_class ')' { $$ = $2; }
 396                 ;
 397
 398 /*----- That's all, folks -------------------------------------------------*/