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

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