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 */
28 %{
30 #include "frontend/connection-private.h"
31 #include "frontend/parser.h"
32 #include "frontend/grammar.h"
34 #include "core/store.h"
35 #include "core/store-private.h"
37 #include "utils/error.h"
38 #include "utils/llist.h"
40 #include <stdio.h>
41 #include <string.h>
43 int
44 sdb_fe_yylex(YYSTYPE *yylval, YYLTYPE *yylloc, sdb_fe_yyscan_t yyscanner);
46 sdb_fe_yyextra_t *
47 sdb_fe_yyget_extra(sdb_fe_yyscan_t scanner);
49 void
50 sdb_fe_yyerror(YYLTYPE *lval, sdb_fe_yyscan_t scanner, const char *msg);
52 /* quick access to the current parse tree */
53 #define pt sdb_fe_yyget_extra(scanner)->parsetree
55 /* quick access to the parser mode */
56 #define parser_mode sdb_fe_yyget_extra(scanner)->mode
58 %}
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"
68 %union {
69 const char *sstr; /* static string */
70 char *str;
72 sdb_data_t data;
74 sdb_llist_t *list;
75 sdb_conn_node_t *node;
77 sdb_store_matcher_t *m;
78 }
80 %start statements
82 %token SCANNER_ERROR
84 %token AND OR NOT WHERE
85 %token CMP_EQUAL CMP_NEQUAL CMP_REGEX CMP_NREGEX
87 %token FETCH LIST LOOKUP
89 %token <str> IDENTIFIER STRING
91 /* Precedence (lowest first): */
92 %left OR
93 %left AND
94 %left NOT
95 %left CMP_EQUAL CMP_NEQUAL
96 %left CMP_REGEX CMP_NREGEX
97 %left '(' ')'
98 %left '.'
100 %type <list> statements
101 %type <node> statement
102 fetch_statement
103 list_statement
104 lookup_statement
105 expression
107 %type <m> matcher
108 compare_matcher
110 %type <sstr> op
112 %type <data> data
114 %destructor { free($$); } <str>
115 %destructor { sdb_object_deref(SDB_OBJ($$)); } <node> <m>
117 %%
119 statements:
120 statements ';' statement
121 {
122 /* only accept this in default parse mode */
123 if (parser_mode != SDB_PARSE_DEFAULT) {
124 sdb_fe_yyerror(&yylloc, scanner,
125 YY_("syntax error, unexpected statement, "
126 "expecting expression"));
127 sdb_object_deref(SDB_OBJ($3));
128 YYABORT;
129 }
131 if ($3) {
132 sdb_llist_append(pt, SDB_OBJ($3));
133 sdb_object_deref(SDB_OBJ($3));
134 }
135 }
136 |
137 statement
138 {
139 /* only accept this in default parse mode */
140 if (parser_mode != SDB_PARSE_DEFAULT) {
141 sdb_fe_yyerror(&yylloc, scanner,
142 YY_("syntax error, unexpected statement, "
143 "expecting expression"));
144 sdb_object_deref(SDB_OBJ($1));
145 YYABORT;
146 }
148 if ($1) {
149 sdb_llist_append(pt, SDB_OBJ($1));
150 sdb_object_deref(SDB_OBJ($1));
151 }
152 }
153 |
154 expression
155 {
156 /* only accept this in expression parse mode */
157 if (! (parser_mode & SDB_PARSE_EXPR)) {
158 sdb_fe_yyerror(&yylloc, scanner,
159 YY_("syntax error, unexpected expression, "
160 "expecting statement"));
161 sdb_object_deref(SDB_OBJ($1));
162 YYABORT;
163 }
165 if ($1) {
166 sdb_llist_append(pt, SDB_OBJ($1));
167 sdb_object_deref(SDB_OBJ($1));
168 }
169 }
170 ;
172 statement:
173 fetch_statement
174 |
175 list_statement
176 |
177 lookup_statement
178 |
179 /* empty */
180 {
181 $$ = NULL;
182 }
183 ;
185 /*
186 * FETCH <hostname>;
187 *
188 * Retrieve detailed information about a single host.
189 */
190 fetch_statement:
191 FETCH STRING
192 {
193 $$ = SDB_CONN_NODE(sdb_object_create_dT(/* name = */ NULL,
194 conn_fetch_t, conn_fetch_destroy));
195 CONN_FETCH($$)->name = strdup($2);
196 $$->cmd = CONNECTION_FETCH;
197 free($2); $2 = NULL;
198 }
199 ;
201 /*
202 * LIST;
203 *
204 * Returns a list of all hosts in the store.
205 */
206 list_statement:
207 LIST
208 {
209 $$ = SDB_CONN_NODE(sdb_object_create_T(/* name = */ NULL,
210 sdb_conn_node_t));
211 $$->cmd = CONNECTION_LIST;
212 }
213 ;
215 /*
216 * LOOKUP <type> WHERE <expression>;
217 *
218 * Returns detailed information about <type> matching expression.
219 */
220 lookup_statement:
221 LOOKUP IDENTIFIER WHERE expression
222 {
223 /* TODO: support other types as well */
224 if (strcasecmp($2, "hosts")) {
225 char errmsg[strlen($2) + 32];
226 snprintf(errmsg, sizeof(errmsg),
227 YY_("unknown table %s"), $2);
228 sdb_fe_yyerror(&yylloc, scanner, errmsg);
229 free($2); $2 = NULL;
230 sdb_object_deref(SDB_OBJ($4));
231 YYABORT;
232 }
234 $$ = SDB_CONN_NODE(sdb_object_create_dT(/* name = */ NULL,
235 conn_lookup_t, conn_lookup_destroy));
236 CONN_LOOKUP($$)->matcher = CONN_MATCHER($4);
237 $$->cmd = CONNECTION_LOOKUP;
238 free($2); $2 = NULL;
239 }
240 ;
242 expression:
243 matcher
244 {
245 if (! $1) {
246 /* TODO: improve error reporting */
247 sdb_fe_yyerror(&yylloc, scanner,
248 YY_("syntax error, invalid expression"));
249 YYABORT;
250 }
252 $$ = SDB_CONN_NODE(sdb_object_create_dT(/* name = */ NULL,
253 conn_node_matcher_t, conn_matcher_destroy));
254 $$->cmd = CONNECTION_EXPR;
255 CONN_MATCHER($$)->matcher = $1;
256 }
257 ;
259 matcher:
260 '(' matcher ')'
261 {
262 $$ = $2;
263 }
264 |
265 matcher AND matcher
266 {
267 $$ = sdb_store_con_matcher($1, $3);
268 sdb_object_deref(SDB_OBJ($1));
269 sdb_object_deref(SDB_OBJ($3));
270 }
271 |
272 matcher OR matcher
273 {
274 $$ = sdb_store_dis_matcher($1, $3);
275 sdb_object_deref(SDB_OBJ($1));
276 sdb_object_deref(SDB_OBJ($3));
277 }
278 |
279 NOT matcher
280 {
281 $$ = sdb_store_inv_matcher($2);
282 sdb_object_deref(SDB_OBJ($2));
283 }
284 |
285 compare_matcher
286 {
287 $$ = $1;
288 }
289 ;
291 /*
292 * <object_type>.<object_attr> <op> <value>
293 *
294 * Parse matchers comparing object attributes with a value.
295 */
296 compare_matcher:
297 IDENTIFIER '.' IDENTIFIER op data
298 {
299 $$ = sdb_store_matcher_parse_cmp($1, $3, $4, &$5);
300 free($1); $1 = NULL;
301 free($3); $3 = NULL;
302 sdb_data_free_datum(&$5);
303 }
304 ;
306 op:
307 CMP_EQUAL { $$ = "="; }
308 |
309 CMP_NEQUAL { $$ = "!="; }
310 |
311 CMP_REGEX { $$ = "=~"; }
312 |
313 CMP_NREGEX { $$ = "!~"; }
314 ;
316 data:
317 STRING { $$.type = SDB_TYPE_STRING; $$.data.string = $1; }
318 ;
320 %%
322 void
323 sdb_fe_yyerror(YYLTYPE *lval, sdb_fe_yyscan_t scanner, const char *msg)
324 {
325 sdb_log(SDB_LOG_ERR, "frontend: parse error: %s", msg);
326 } /* sdb_fe_yyerror */
328 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */