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 #include "core/store-private.h"
  36
  37 #include "utils/error.h"
  38 #include "utils/llist.h"
  39
  40 #include <stdio.h>
  41 #include <string.h>
  42
  43 int
  44 sdb_fe_yylex(YYSTYPE *yylval, YYLTYPE *yylloc, sdb_fe_yyscan_t yyscanner);
  45
  46 sdb_fe_yyextra_t *
  47 sdb_fe_yyget_extra(sdb_fe_yyscan_t scanner);
  48
  49 void
  50 sdb_fe_yyerror(YYLTYPE *lval, sdb_fe_yyscan_t scanner, const char *msg);
  51
  52 /* quick access to the current parse tree */
  53 #define pt sdb_fe_yyget_extra(scanner)->parsetree
  54
  55 /* quick access to the parser mode */
  56 #define parser_mode sdb_fe_yyget_extra(scanner)->mode
  57
  58 %}
  59
  60 %pure-parser
  61 %lex-param {sdb_fe_yyscan_t scanner}
  62 %parse-param {sdb_fe_yyscan_t scanner}
  63 %locations
  64 %error-verbose
  65 %expect 0
  66 %name-prefix "sdb_fe_yy"
  67
  68 %union {
  69         const char *sstr; /* static string */
  70         char *str;
  71
  72         sdb_data_t data;
  73
  74         sdb_llist_t     *list;
  75         sdb_conn_node_t *node;
  76
  77         sdb_store_matcher_t *m;
  78         sdb_store_expr_t *expr;
  79 }
  80
  81 %start statements
  82
  83 %token SCANNER_ERROR
  84
  85 %token AND OR IS NOT MATCHING
  86 %token CMP_EQUAL CMP_NEQUAL CMP_REGEX CMP_NREGEX
  87 %token CMP_LT CMP_LE CMP_GE CMP_GT
  88 %token CONCAT
  89
  90 /* NULL token */
  91 %token NULL_T
  92
  93 %token FETCH LIST LOOKUP
  94
  95 %token <str> IDENTIFIER STRING
  96
  97 %token <data> INTEGER FLOAT
  98
  99 /* Precedence (lowest first): */
 100 %left OR
 101 %left AND
 102 %right NOT
 103 %left CMP_EQUAL CMP_NEQUAL
 104 %left CMP_LT CMP_LE CMP_GE CMP_GT
 105 %nonassoc CMP_REGEX CMP_NREGEX
 106 %left CONCAT
 107 %nonassoc IS
 108 %left '+' '-'
 109 %left '*' '/' '%'
 110 %left '(' ')'
 111 %left '.'
 112
 113 %type <list> statements
 114 %type <node> statement
 115         fetch_statement
 116         list_statement
 117         lookup_statement
 118         condition
 119
 120 %type <m> matcher
 121         compare_matcher
 122
 123 %type <expr> expression
 124
 125 %type <sstr> op
 126
 127 %type <data> data
 128         interval interval_elem
 129
 130 %destructor { free($$); } <str>
 131 %destructor { sdb_object_deref(SDB_OBJ($$)); } <node> <m> <expr>
 132
 133 %%
 134
 135 statements:
 136         statements ';' statement
 137                 {
 138                         /* only accept this in default parse mode */
 139                         if (parser_mode != SDB_PARSE_DEFAULT) {
 140                                 sdb_fe_yyerror(&yylloc, scanner,
 141                                                 YY_("syntax error, unexpected statement, "
 142                                                         "expecting condition"));
 143                                 sdb_object_deref(SDB_OBJ($3));
 144                                 YYABORT;
 145                         }
 146
 147                         if ($3) {
 148                                 sdb_llist_append(pt, SDB_OBJ($3));
 149                                 sdb_object_deref(SDB_OBJ($3));
 150                         }
 151                 }
 152         |
 153         statement
 154                 {
 155                         /* only accept this in default parse mode */
 156                         if (parser_mode != SDB_PARSE_DEFAULT) {
 157                                 sdb_fe_yyerror(&yylloc, scanner,
 158                                                 YY_("syntax error, unexpected statement, "
 159                                                         "expecting condition"));
 160                                 sdb_object_deref(SDB_OBJ($1));
 161                                 YYABORT;
 162                         }
 163
 164                         if ($1) {
 165                                 sdb_llist_append(pt, SDB_OBJ($1));
 166                                 sdb_object_deref(SDB_OBJ($1));
 167                         }
 168                 }
 169         |
 170         condition
 171                 {
 172                         /* only accept this in condition parse mode */
 173                         if (! (parser_mode & SDB_PARSE_COND)) {
 174                                 sdb_fe_yyerror(&yylloc, scanner,
 175                                                 YY_("syntax error, unexpected condition, "
 176                                                         "expecting statement"));
 177                                 sdb_object_deref(SDB_OBJ($1));
 178                                 YYABORT;
 179                         }
 180
 181                         if ($1) {
 182                                 sdb_llist_append(pt, SDB_OBJ($1));
 183                                 sdb_object_deref(SDB_OBJ($1));
 184                         }
 185                 }
 186         ;
 187
 188 statement:
 189         fetch_statement
 190         |
 191         list_statement
 192         |
 193         lookup_statement
 194         |
 195         /* empty */
 196                 {
 197                         $$ = NULL;
 198                 }
 199         ;
 200
 201 /*
 202  * FETCH <hostname>;
 203  *
 204  * Retrieve detailed information about a single host.
 205  */
 206 fetch_statement:
 207         FETCH STRING
 208                 {
 209                         $$ = SDB_CONN_NODE(sdb_object_create_dT(/* name = */ NULL,
 210                                                 conn_fetch_t, conn_fetch_destroy));
 211                         CONN_FETCH($$)->name = strdup($2);
 212                         $$->cmd = CONNECTION_FETCH;
 213                         free($2); $2 = NULL;
 214                 }
 215         ;
 216
 217 /*
 218  * LIST;
 219  *
 220  * Returns a list of all hosts in the store.
 221  */
 222 list_statement:
 223         LIST
 224                 {
 225                         $$ = SDB_CONN_NODE(sdb_object_create_T(/* name = */ NULL,
 226                                                 sdb_conn_node_t));
 227                         $$->cmd = CONNECTION_LIST;
 228                 }
 229         ;
 230
 231 /*
 232  * LOOKUP <type> MATCHING <condition>;
 233  *
 234  * Returns detailed information about <type> matching condition.
 235  */
 236 lookup_statement:
 237         LOOKUP IDENTIFIER MATCHING condition
 238                 {
 239                         /* TODO: support other types as well */
 240                         if (strcasecmp($2, "hosts")) {
 241                                 char errmsg[strlen($2) + 32];
 242                                 snprintf(errmsg, sizeof(errmsg),
 243                                                 YY_("unknown table %s"), $2);
 244                                 sdb_fe_yyerror(&yylloc, scanner, errmsg);
 245                                 free($2); $2 = NULL;
 246                                 sdb_object_deref(SDB_OBJ($4));
 247                                 YYABORT;
 248                         }
 249
 250                         $$ = SDB_CONN_NODE(sdb_object_create_dT(/* name = */ NULL,
 251                                                 conn_lookup_t, conn_lookup_destroy));
 252                         CONN_LOOKUP($$)->matcher = CONN_MATCHER($4);
 253                         $$->cmd = CONNECTION_LOOKUP;
 254                         free($2); $2 = NULL;
 255                 }
 256         ;
 257
 258 condition:
 259         matcher
 260                 {
 261                         if (! $1) {
 262                                 /* TODO: improve error reporting */
 263                                 sdb_fe_yyerror(&yylloc, scanner,
 264                                                 YY_("syntax error, invalid condition"));
 265                                 YYABORT;
 266                         }
 267
 268                         $$ = SDB_CONN_NODE(sdb_object_create_dT(/* name = */ NULL,
 269                                                 conn_node_matcher_t, conn_matcher_destroy));
 270                         $$->cmd = CONNECTION_EXPR;
 271                         CONN_MATCHER($$)->matcher = $1;
 272                 }
 273         ;
 274
 275 matcher:
 276         '(' matcher ')'
 277                 {
 278                         $$ = $2;
 279                 }
 280         |
 281         matcher AND matcher
 282                 {
 283                         $$ = sdb_store_con_matcher($1, $3);
 284                         sdb_object_deref(SDB_OBJ($1));
 285                         sdb_object_deref(SDB_OBJ($3));
 286                 }
 287         |
 288         matcher OR matcher
 289                 {
 290                         $$ = sdb_store_dis_matcher($1, $3);
 291                         sdb_object_deref(SDB_OBJ($1));
 292                         sdb_object_deref(SDB_OBJ($3));
 293                 }
 294         |
 295         NOT matcher
 296                 {
 297                         $$ = sdb_store_inv_matcher($2);
 298                         sdb_object_deref(SDB_OBJ($2));
 299                 }
 300         |
 301         compare_matcher
 302                 {
 303                         $$ = $1;
 304                 }
 305         ;
 306
 307 /*
 308  * <object_type>.<object_attr> <op> <value>
 309  *
 310  * Parse matchers comparing object attributes with a value.
 311  */
 312 compare_matcher:
 313         ':' IDENTIFIER op expression
 314                 {
 315                         $$ = sdb_store_matcher_parse_field_cmp($2, $3, $4);
 316                         free($2); $2 = NULL;
 317                         sdb_object_deref(SDB_OBJ($4));
 318                 }
 319         |
 320         IDENTIFIER op expression
 321                 {
 322                         $$ = sdb_store_matcher_parse_cmp($1, NULL, $2, $3);
 323                         free($1); $1 = NULL;
 324                         sdb_object_deref(SDB_OBJ($3));
 325                 }
 326         |
 327         IDENTIFIER '.' IDENTIFIER op expression
 328                 {
 329                         $$ = sdb_store_matcher_parse_cmp($1, $3, $4, $5);
 330                         free($1); $1 = NULL;
 331                         free($3); $3 = NULL;
 332                         sdb_object_deref(SDB_OBJ($5));
 333                 }
 334         |
 335         IDENTIFIER '.' IDENTIFIER IS NULL_T
 336                 {
 337                         $$ = sdb_store_matcher_parse_cmp($1, $3, "IS", NULL);
 338                         free($1); $1 = NULL;
 339                         free($3); $3 = NULL;
 340                 }
 341         |
 342         IDENTIFIER '.' IDENTIFIER IS NOT NULL_T
 343                 {
 344                         sdb_store_matcher_t *m;
 345                         m = sdb_store_matcher_parse_cmp($1, $3, "IS", NULL);
 346                         free($1); $1 = NULL;
 347                         free($3); $3 = NULL;
 348
 349                         /* sdb_store_inv_matcher return NULL if m==NULL */
 350                         $$ = sdb_store_inv_matcher(m);
 351                         sdb_object_deref(SDB_OBJ(m));
 352                 }
 353         ;
 354
 355 expression:
 356         '(' expression ')'
 357                 {
 358                         $$ = $2;
 359                 }
 360         |
 361         expression '+' expression
 362                 {
 363                         $$ = sdb_store_expr_create(SDB_DATA_ADD, $1, $3);
 364                         sdb_object_deref(SDB_OBJ($1)); $1 = NULL;
 365                         sdb_object_deref(SDB_OBJ($3)); $3 = NULL;
 366                 }
 367         |
 368         expression '-' expression
 369                 {
 370                         $$ = sdb_store_expr_create(SDB_DATA_SUB, $1, $3);
 371                         sdb_object_deref(SDB_OBJ($1)); $1 = NULL;
 372                         sdb_object_deref(SDB_OBJ($3)); $3 = NULL;
 373                 }
 374         |
 375         expression '*' expression
 376                 {
 377                         $$ = sdb_store_expr_create(SDB_DATA_MUL, $1, $3);
 378                         sdb_object_deref(SDB_OBJ($1)); $1 = NULL;
 379                         sdb_object_deref(SDB_OBJ($3)); $3 = NULL;
 380                 }
 381         |
 382         expression '/' expression
 383                 {
 384                         $$ = sdb_store_expr_create(SDB_DATA_DIV, $1, $3);
 385                         sdb_object_deref(SDB_OBJ($1)); $1 = NULL;
 386                         sdb_object_deref(SDB_OBJ($3)); $3 = NULL;
 387                 }
 388         |
 389         expression '%' expression
 390                 {
 391                         $$ = sdb_store_expr_create(SDB_DATA_MOD, $1, $3);
 392                         sdb_object_deref(SDB_OBJ($1)); $1 = NULL;
 393                         sdb_object_deref(SDB_OBJ($3)); $3 = NULL;
 394                 }
 395         |
 396         data
 397                 {
 398                         $$ = sdb_store_expr_constvalue(&$1);
 399                         sdb_data_free_datum(&$1);
 400                 }
 401         ;
 402
 403 op:
 404         CMP_EQUAL { $$ = "="; }
 405         |
 406         CMP_NEQUAL { $$ = "!="; }
 407         |
 408         CMP_REGEX { $$ = "=~"; }
 409         |
 410         CMP_NREGEX { $$ = "!~"; }
 411         |
 412         CMP_LT { $$ = "<"; }
 413         |
 414         CMP_LE { $$ = "<="; }
 415         |
 416         CMP_GE { $$ = ">="; }
 417         |
 418         CMP_GT { $$ = ">"; }
 419         ;
 420
 421 data:
 422         STRING { $$.type = SDB_TYPE_STRING; $$.data.string = $1; }
 423         |
 424         INTEGER { $$ = $1; }
 425         |
 426         FLOAT { $$ = $1; }
 427         |
 428         interval { $$ = $1; }
 429         ;
 430
 431 interval:
 432         interval interval_elem
 433                 {
 434                         $$.data.datetime = $1.data.datetime + $2.data.datetime;
 435                 }
 436         |
 437         interval_elem { $$ = $1; }
 438         ;
 439
 440 interval_elem:
 441         INTEGER IDENTIFIER
 442                 {
 443                         sdb_time_t unit = 1;
 444
 445                         unit = sdb_strpunit($2);
 446                         if (! unit) {
 447                                 char errmsg[strlen($2) + 32];
 448                                 snprintf(errmsg, sizeof(errmsg),
 449                                                 YY_("invalid time unit %s"), $2);
 450                                 sdb_fe_yyerror(&yylloc, scanner, errmsg);
 451                                 free($2); $2 = NULL;
 452                                 YYABORT;
 453                         }
 454                         free($2); $2 = NULL;
 455
 456                         $$.type = SDB_TYPE_DATETIME;
 457                         $$.data.datetime = (sdb_time_t)$1.data.integer * unit;
 458
 459                         if ($1.data.integer < 0) {
 460                                 sdb_fe_yyerror(&yylloc, scanner,
 461                                                 YY_("syntax error, negative intervals not supported"));
 462                                 YYABORT;
 463                         }
 464                 }
 465         ;
 466
 467 %%
 468
 469 void
 470 sdb_fe_yyerror(YYLTYPE *lval, sdb_fe_yyscan_t scanner, const char *msg)
 471 {
 472         sdb_log(SDB_LOG_ERR, "frontend: parse error: %s", msg);
 473 } /* sdb_fe_yyerror */
 474
 475 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 476