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 char *str;
71 sdb_llist_t *list;
72 sdb_conn_node_t *node;
74 sdb_store_matcher_t *m;
75 }
77 %start statements
79 %token SCANNER_ERROR
81 %token AND OR WHERE
83 %token CMP_EQUAL CMP_REGEX
85 %token <str> IDENTIFIER STRING
86 %token <node> FETCH LIST LOOKUP
88 /* Precedence (lowest first): */
89 %left OR
90 %left AND
91 %left CMP_EQUAL
92 %left CMP_REGEX
94 %type <list> statements
95 %type <node> statement
96 fetch_statement
97 list_statement
98 lookup_statement
99 expression
101 %type <m> matcher
102 compare_matcher
104 %%
106 statements:
107 statements ';' statement
108 {
109 /* only accept this in default parse mode */
110 if (parser_mode != SDB_PARSE_DEFAULT) {
111 sdb_fe_yyerror(&yylloc, scanner,
112 YY_("syntax error, unexpected statement, "
113 "expecting expression"));
114 sdb_object_deref(SDB_OBJ($3));
115 YYABORT;
116 }
118 if ($3) {
119 sdb_llist_append(pt, SDB_OBJ($3));
120 sdb_object_deref(SDB_OBJ($3));
121 }
122 }
123 |
124 statement
125 {
126 /* only accept this in default parse mode */
127 if (parser_mode != SDB_PARSE_DEFAULT) {
128 sdb_fe_yyerror(&yylloc, scanner,
129 YY_("syntax error, unexpected statement, "
130 "expecting expression"));
131 sdb_object_deref(SDB_OBJ($1));
132 YYABORT;
133 }
135 if ($1) {
136 sdb_llist_append(pt, SDB_OBJ($1));
137 sdb_object_deref(SDB_OBJ($1));
138 }
139 }
140 |
141 expression
142 {
143 /* only accept this in expression parse mode */
144 if (! (parser_mode & SDB_PARSE_EXPR)) {
145 sdb_fe_yyerror(&yylloc, scanner,
146 YY_("syntax error, unexpected expression, "
147 "expecting statement"));
148 sdb_object_deref(SDB_OBJ($1));
149 YYABORT;
150 }
152 if ($1) {
153 sdb_llist_append(pt, SDB_OBJ($1));
154 sdb_object_deref(SDB_OBJ($1));
155 }
156 }
157 ;
159 statement:
160 fetch_statement
161 |
162 list_statement
163 |
164 lookup_statement
165 |
166 /* empty */
167 {
168 $$ = NULL;
169 }
170 ;
172 /*
173 * FETCH <hostname>;
174 *
175 * Retrieve detailed information about a single host.
176 */
177 fetch_statement:
178 FETCH STRING
179 {
180 $$ = SDB_CONN_NODE(sdb_object_create_dT(/* name = */ NULL,
181 conn_fetch_t, conn_fetch_destroy));
182 CONN_FETCH($$)->name = strdup($2);
183 $$->cmd = CONNECTION_FETCH;
184 free($2); $2 = NULL;
185 }
186 ;
188 /*
189 * LIST;
190 *
191 * Returns a list of all hosts in the store.
192 */
193 list_statement:
194 LIST
195 {
196 $$ = SDB_CONN_NODE(sdb_object_create_T(/* name = */ NULL,
197 sdb_conn_node_t));
198 $$->cmd = CONNECTION_LIST;
199 }
200 ;
202 /*
203 * LOOKUP <type> WHERE <expression>;
204 *
205 * Returns detailed information about <type> matching expression.
206 */
207 lookup_statement:
208 LOOKUP IDENTIFIER WHERE expression
209 {
210 /* TODO: support other types as well */
211 if (strcasecmp($2, "hosts")) {
212 char errmsg[strlen($2) + 32];
213 snprintf(errmsg, sizeof(errmsg),
214 YY_("unknown table %s"), $2);
215 sdb_fe_yyerror(&yylloc, scanner, errmsg);
216 free($2); $2 = NULL;
217 sdb_object_deref(SDB_OBJ($4));
218 YYABORT;
219 }
221 $$ = SDB_CONN_NODE(sdb_object_create_dT(/* name = */ NULL,
222 conn_lookup_t, conn_lookup_destroy));
223 CONN_LOOKUP($$)->matcher = CONN_MATCHER($4);
224 $$->cmd = CONNECTION_LOOKUP;
225 free($2); $2 = NULL;
226 }
227 ;
229 expression:
230 matcher
231 {
232 sdb_store_matcher_t *m = $1;
233 if (! m) {
234 /* TODO: improve error reporting */
235 sdb_fe_yyerror(&yylloc, scanner,
236 YY_("syntax error, invalid expression"));
237 YYABORT;
238 }
240 $$ = SDB_CONN_NODE(sdb_object_create_dT(/* name = */ NULL,
241 conn_node_matcher_t, conn_matcher_destroy));
242 $$->cmd = CONNECTION_EXPR;
244 if ((M(m)->type == MATCHER_HOST)
245 || (M(m)->type == MATCHER_AND)
246 || (M(m)->type == MATCHER_OR))
247 CONN_MATCHER($$)->matcher = m;
248 else if (M(m)->type == MATCHER_SERVICE)
249 CONN_MATCHER($$)->matcher = sdb_store_host_matcher(NULL,
250 /* name_re = */ NULL, /* service = */ m,
251 /* attr = */ NULL);
252 else if (M(m)->type == MATCHER_ATTR)
253 CONN_MATCHER($$)->matcher = sdb_store_host_matcher(NULL,
254 /* name_re = */ NULL, /* service = */ NULL,
255 /* attr = */ m);
256 else {
257 char errbuf[1024];
258 snprintf(errbuf, sizeof(errbuf),
259 YY_("syntax error, unexpected matcher type %d"),
260 M(m)->type);
261 sdb_object_deref(SDB_OBJ($$));
262 sdb_fe_yyerror(&yylloc, scanner, errbuf);
263 YYABORT;
264 }
265 }
266 ;
268 matcher:
269 matcher AND matcher
270 {
271 $$ = sdb_store_con_matcher($1, $3);
272 }
273 |
274 matcher OR matcher
275 {
276 $$ = sdb_store_dis_matcher($1, $3);
277 }
278 |
279 compare_matcher
280 {
281 $$ = $1;
282 }
283 ;
285 /*
286 * <object_type>.<object_attr> <op> <value>
287 *
288 * Parse matchers comparing object attributes with a value.
289 */
290 compare_matcher:
291 IDENTIFIER '.' IDENTIFIER CMP_EQUAL STRING
292 {
293 $$ = sdb_store_matcher_parse_cmp($1, $3, "=", $5);
294 /* TODO: simplify memory management in the parser */
295 free($1); $1 = NULL;
296 free($3); $3 = NULL;
297 free($5); $5 = NULL;
298 }
299 |
300 IDENTIFIER '.' IDENTIFIER CMP_REGEX STRING
301 {
302 $$ = sdb_store_matcher_parse_cmp($1, $3, "=~", $5);
303 free($1); $1 = NULL;
304 free($3); $3 = NULL;
305 free($5); $5 = NULL;
306 }
307 ;
309 %%
311 void
312 sdb_fe_yyerror(YYLTYPE *lval, sdb_fe_yyscan_t scanner, const char *msg)
313 {
314 sdb_log(SDB_LOG_ERR, "frontend: parse error: %s", msg);
315 } /* sdb_fe_yyerror */
317 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */