src/frontend/grammar.y

   1 /*
   2  * SysDB - src/frontend/grammar.y
   3  * Copyright (C) 2013 Sebastian 'tokkee' Harl <sh@tokkee.org>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  16  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  17  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  18  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
  19  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  20  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 %{
  29
  30 #include "frontend/connection-private.h"
  31 #include "frontend/parser.h"
  32 #include "frontend/grammar.h"
  33
  34 #include "core/store.h"
  35
  36 #include "utils/error.h"
  37 #include "utils/llist.h"
  38
  39 #include <stdio.h>
  40 #include <string.h>
  41
  42 int
  43 sdb_fe_yylex(YYSTYPE *yylval, YYLTYPE *yylloc, sdb_fe_yyscan_t yyscanner);
  44
  45 sdb_fe_yyextra_t *
  46 sdb_fe_yyget_extra(sdb_fe_yyscan_t scanner);
  47
  48 void
  49 sdb_fe_yyerror(YYLTYPE *lval, sdb_fe_yyscan_t scanner, const char *msg);
  50
  51 /* quick access to the current parse tree */
  52 #define pt sdb_fe_yyget_extra(scanner)->parsetree
  53
  54 /* quick access to the parser mode */
  55 #define parser_mode sdb_fe_yyget_extra(scanner)->mode
  56
  57 %}
  58
  59 %pure-parser
  60 %lex-param {sdb_fe_yyscan_t scanner}
  61 %parse-param {sdb_fe_yyscan_t scanner}
  62 %locations
  63 %error-verbose
  64 %expect 0
  65 %name-prefix="sdb_fe_yy"
  66
  67 %union {
  68         char *str;
  69
  70         sdb_llist_t     *list;
  71         sdb_conn_node_t *node;
  72 }
  73
  74 %start statements
  75
  76 %token SCANNER_ERROR
  77
  78 %token WHERE
  79
  80 %token <str> IDENTIFIER STRING
  81 %token <node> FETCH LIST LOOKUP
  82
  83 %type <list> statements
  84 %type <node> statement
  85         fetch_statement
  86         list_statement
  87         lookup_statement
  88         expression
  89
  90 %%
  91
  92 statements:
  93         statements ';' statement
  94                 {
  95                         /* only accept this in default parse mode */
  96                         if (parser_mode != SDB_PARSE_DEFAULT) {
  97                                 sdb_fe_yyerror(&yylloc, scanner,
  98                                                 YY_("syntax error, unexpected statement, "
  99                                                         "expecting expression"));
 100                                 YYABORT;
 101                         }
 102
 103                         if ($3) {
 104                                 sdb_llist_append(pt, SDB_OBJ($3));
 105                                 sdb_object_deref(SDB_OBJ($3));
 106                         }
 107                 }
 108         |
 109         statement
 110                 {
 111                         /* only accept this in default parse mode */
 112                         if (parser_mode != SDB_PARSE_DEFAULT) {
 113                                 sdb_fe_yyerror(&yylloc, scanner,
 114                                                 YY_("syntax error, unexpected statement, "
 115                                                         "expecting expression"));
 116                                 YYABORT;
 117                         }
 118
 119                         if ($1) {
 120                                 sdb_llist_append(pt, SDB_OBJ($1));
 121                                 sdb_object_deref(SDB_OBJ($1));
 122                         }
 123                 }
 124         |
 125         expression
 126                 {
 127                         /* only accept this in expression parse mode */
 128                         if (! (parser_mode & SDB_PARSE_EXPR)) {
 129                                 sdb_fe_yyerror(&yylloc, scanner,
 130                                                 YY_("syntax error, unexpected expression, "
 131                                                         "expecting statement"));
 132                                 YYABORT;
 133                         }
 134
 135                         if ($1) {
 136                                 sdb_llist_append(pt, SDB_OBJ($1));
 137                                 sdb_object_deref(SDB_OBJ($1));
 138                         }
 139                 }
 140         ;
 141
 142 statement:
 143         fetch_statement
 144         |
 145         list_statement
 146         |
 147         lookup_statement
 148         |
 149         /* empty */
 150                 {
 151                         $$ = NULL;
 152                 }
 153         ;
 154
 155 /*
 156  * FETCH <hostname>;
 157  *
 158  * Retrieve detailed information about a single host.
 159  */
 160 fetch_statement:
 161         FETCH STRING
 162                 {
 163                         $$ = SDB_CONN_NODE(sdb_object_create_dT(/* name = */ NULL,
 164                                                 conn_fetch_t, conn_fetch_destroy));
 165                         CONN_FETCH($$)->name = strdup($2);
 166                         $$->cmd = CONNECTION_FETCH;
 167                         free($2);
 168                         $2 = NULL;
 169                 }
 170         ;
 171
 172 /*
 173  * LIST;
 174  *
 175  * Returns a list of all hosts in the store.
 176  */
 177 list_statement:
 178         LIST
 179                 {
 180                         $$ = SDB_CONN_NODE(sdb_object_create_T(/* name = */ NULL,
 181                                                 sdb_conn_node_t));
 182                         $$->cmd = CONNECTION_LIST;
 183                 }
 184         ;
 185
 186 /*
 187  * LOOKUP <type> WHERE <expression>;
 188  *
 189  * Returns detailed information about <type> matching expression.
 190  */
 191 lookup_statement:
 192         LOOKUP IDENTIFIER WHERE expression
 193                 {
 194                         /* TODO: support other types as well */
 195                         if (strcasecmp($2, "hosts")) {
 196                                 char errmsg[strlen($2) + 32];
 197                                 snprintf(errmsg, sizeof(errmsg),
 198                                                 YY_("unknown table %s"), $2);
 199                                 sdb_fe_yyerror(&yylloc, scanner, errmsg);
 200                                 YYABORT;
 201                         }
 202
 203                         $$ = SDB_CONN_NODE(sdb_object_create_dT(/* name = */ NULL,
 204                                                 conn_lookup_t, conn_lookup_destroy));
 205                         CONN_LOOKUP($$)->matcher = CONN_MATCHER($4);
 206                         $$->cmd = CONNECTION_LOOKUP;
 207                         free($2);
 208                         $2 = NULL;
 209                 }
 210         ;
 211
 212 expression:
 213         STRING
 214                 {
 215                         $$ = SDB_CONN_NODE(sdb_object_create_T(/* name = */ NULL,
 216                                                 conn_node_matcher_t));
 217                         $$->cmd = CONNECTION_EXPR;
 218                         /* XXX: this is just a placeholder for now */
 219                         CONN_MATCHER($$)->matcher = sdb_store_host_matcher($1,
 220                                         /* name_re = */ NULL, /* service = */ NULL,
 221                                         /* attr = */ NULL);
 222                         free($1);
 223                         $1 = NULL;
 224                 }
 225         ;
 226
 227 %%
 228
 229 void
 230 sdb_fe_yyerror(YYLTYPE *lval, sdb_fe_yyscan_t scanner, const char *msg)
 231 {
 232         sdb_log(SDB_LOG_ERR, "frontend: parse error: %s", msg);
 233 } /* sdb_fe_yyerror */
 234
 235 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 236