]>
Commit | Line | Data |
---|---|---|
1 | /* | |
2 | * Command format string parser for CLI backend. | |
3 | * | |
4 | * -- | |
5 | * Copyright (C) 2016 Cumulus Networks, Inc. | |
6 | * | |
7 | * This file is part of GNU Zebra. | |
8 | * | |
9 | * GNU Zebra is free software; you can redistribute it and/or modify it | |
10 | * under the terms of the GNU General Public License as published by the | |
11 | * Free Software Foundation; either version 2, or (at your option) any | |
12 | * later version. | |
13 | * | |
14 | * GNU Zebra is distributed in the hope that it will be useful, but | |
15 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | * General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU General Public License | |
20 | * along with GNU Zebra; see the file COPYING. If not, write to the Free | |
21 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA | |
22 | * 02111-1307, USA. | |
23 | */ | |
24 | ||
25 | %{ | |
26 | // compile with debugging facilities | |
27 | #define YYDEBUG 1 | |
28 | %} | |
29 | ||
30 | %locations | |
31 | /* define parse.error verbose */ | |
32 | %define api.pure full | |
33 | /* define api.prefix {cmd_yy} */ | |
34 | ||
35 | /* names for generated header and parser files */ | |
36 | %defines "lib/command_parse.h" | |
37 | %output "lib/command_parse.c" | |
38 | ||
39 | /* note: code blocks are output in order, to both .c and .h: | |
40 | * 1. %code requires | |
41 | * 2. %union + bison forward decls | |
42 | * 3. %code provides | |
43 | * command_lex.h needs to be included at 3.; it needs the union and YYSTYPE. | |
44 | * struct parser_ctx is needed for the bison forward decls. | |
45 | */ | |
46 | %code requires { | |
47 | #include "config.h" | |
48 | ||
49 | #include <stdlib.h> | |
50 | #include <string.h> | |
51 | #include <ctype.h> | |
52 | ||
53 | #include "command_graph.h" | |
54 | #include "log.h" | |
55 | ||
56 | DECLARE_MTYPE(LEX) | |
57 | ||
58 | #define YYSTYPE CMD_YYSTYPE | |
59 | #define YYLTYPE CMD_YYLTYPE | |
60 | struct parser_ctx; | |
61 | ||
62 | /* subgraph semantic value */ | |
63 | struct subgraph { | |
64 | struct graph_node *start, *end; | |
65 | }; | |
66 | } | |
67 | ||
68 | %union { | |
69 | long long number; | |
70 | char *string; | |
71 | struct graph_node *node; | |
72 | struct subgraph subgraph; | |
73 | } | |
74 | ||
75 | %code provides { | |
76 | #ifndef FLEX_SCANNER | |
77 | #include "command_lex.h" | |
78 | #endif | |
79 | ||
80 | extern void set_lexer_string (yyscan_t *scn, const char *string); | |
81 | extern void cleanup_lexer (yyscan_t *scn); | |
82 | ||
83 | struct parser_ctx { | |
84 | yyscan_t scanner; | |
85 | ||
86 | struct cmd_element *el; | |
87 | ||
88 | struct graph *graph; | |
89 | struct graph_node *currnode; | |
90 | ||
91 | /* pointers to copy of command docstring */ | |
92 | char *docstr_start, *docstr; | |
93 | }; | |
94 | } | |
95 | ||
96 | /* union types for lexed tokens */ | |
97 | %token <string> WORD | |
98 | %token <string> IPV4 | |
99 | %token <string> IPV4_PREFIX | |
100 | %token <string> IPV6 | |
101 | %token <string> IPV6_PREFIX | |
102 | %token <string> VARIABLE | |
103 | %token <string> RANGE | |
104 | %token <string> MAC | |
105 | %token <string> MAC_PREFIX | |
106 | ||
107 | /* union types for parsed rules */ | |
108 | %type <node> start | |
109 | %type <node> literal_token | |
110 | %type <node> placeholder_token | |
111 | %type <node> placeholder_token_real | |
112 | %type <node> simple_token | |
113 | %type <subgraph> selector | |
114 | %type <subgraph> selector_token | |
115 | %type <subgraph> selector_token_seq | |
116 | %type <subgraph> selector_seq_seq | |
117 | ||
118 | %type <string> varname_token | |
119 | ||
120 | %code { | |
121 | ||
122 | /* bison declarations */ | |
123 | void | |
124 | cmd_yyerror (CMD_YYLTYPE *locp, struct parser_ctx *ctx, char const *msg); | |
125 | ||
126 | /* helper functions for parser */ | |
127 | static const char * | |
128 | doc_next (struct parser_ctx *ctx); | |
129 | ||
130 | static struct graph_node * | |
131 | new_token_node (struct parser_ctx *, | |
132 | enum cmd_token_type type, | |
133 | const char *text, | |
134 | const char *doc); | |
135 | ||
136 | static void | |
137 | terminate_graph (CMD_YYLTYPE *locp, struct parser_ctx *ctx, | |
138 | struct graph_node *); | |
139 | ||
140 | static void | |
141 | cleanup (struct parser_ctx *ctx); | |
142 | ||
143 | #define scanner ctx->scanner | |
144 | } | |
145 | ||
146 | /* yyparse parameters */ | |
147 | %lex-param {yyscan_t scanner} | |
148 | %parse-param {struct parser_ctx *ctx} | |
149 | ||
150 | /* called automatically before yyparse */ | |
151 | %initial-action { | |
152 | /* clear state pointers */ | |
153 | ctx->currnode = vector_slot (ctx->graph->nodes, 0); | |
154 | ||
155 | /* copy docstring and keep a pointer to the copy */ | |
156 | if (ctx->el->doc) | |
157 | { | |
158 | // allocate a new buffer, making room for a flag | |
159 | size_t length = (size_t) strlen (ctx->el->doc) + 2; | |
160 | ctx->docstr = malloc (length); | |
161 | memcpy (ctx->docstr, ctx->el->doc, strlen (ctx->el->doc)); | |
162 | // set the flag so doc_next knows when to print a warning | |
163 | ctx->docstr[length - 2] = 0x03; | |
164 | // null terminate | |
165 | ctx->docstr[length - 1] = 0x00; | |
166 | } | |
167 | ctx->docstr_start = ctx->docstr; | |
168 | } | |
169 | ||
170 | %% | |
171 | ||
172 | start: | |
173 | cmd_token_seq | |
174 | { | |
175 | // tack on the command element | |
176 | terminate_graph (&@1, ctx, ctx->currnode); | |
177 | } | |
178 | | cmd_token_seq placeholder_token '.' '.' '.' | |
179 | { | |
180 | if ((ctx->currnode = graph_add_edge (ctx->currnode, $2)) != $2) | |
181 | graph_delete_node (ctx->graph, $2); | |
182 | ||
183 | ((struct cmd_token *)ctx->currnode->data)->allowrepeat = 1; | |
184 | ||
185 | // adding a node as a child of itself accepts any number | |
186 | // of the same token, which is what we want for variadics | |
187 | graph_add_edge (ctx->currnode, ctx->currnode); | |
188 | ||
189 | // tack on the command element | |
190 | terminate_graph (&@1, ctx, ctx->currnode); | |
191 | } | |
192 | ; | |
193 | ||
194 | varname_token: '$' WORD | |
195 | { | |
196 | $$ = $2; | |
197 | } | |
198 | | /* empty */ | |
199 | { | |
200 | $$ = NULL; | |
201 | } | |
202 | ; | |
203 | ||
204 | cmd_token_seq: | |
205 | /* empty */ | |
206 | | cmd_token_seq cmd_token | |
207 | ; | |
208 | ||
209 | cmd_token: | |
210 | simple_token | |
211 | { | |
212 | if ((ctx->currnode = graph_add_edge (ctx->currnode, $1)) != $1) | |
213 | graph_delete_node (ctx->graph, $1); | |
214 | } | |
215 | | selector | |
216 | { | |
217 | graph_add_edge (ctx->currnode, $1.start); | |
218 | ctx->currnode = $1.end; | |
219 | } | |
220 | ; | |
221 | ||
222 | simple_token: | |
223 | literal_token | |
224 | | placeholder_token | |
225 | ; | |
226 | ||
227 | literal_token: WORD varname_token | |
228 | { | |
229 | $$ = new_token_node (ctx, WORD_TKN, $1, doc_next(ctx)); | |
230 | cmd_token_varname_set ($$->data, $2); | |
231 | XFREE (MTYPE_LEX, $2); | |
232 | XFREE (MTYPE_LEX, $1); | |
233 | } | |
234 | ; | |
235 | ||
236 | placeholder_token_real: | |
237 | IPV4 | |
238 | { | |
239 | $$ = new_token_node (ctx, IPV4_TKN, $1, doc_next(ctx)); | |
240 | XFREE (MTYPE_LEX, $1); | |
241 | } | |
242 | | IPV4_PREFIX | |
243 | { | |
244 | $$ = new_token_node (ctx, IPV4_PREFIX_TKN, $1, doc_next(ctx)); | |
245 | XFREE (MTYPE_LEX, $1); | |
246 | } | |
247 | | IPV6 | |
248 | { | |
249 | $$ = new_token_node (ctx, IPV6_TKN, $1, doc_next(ctx)); | |
250 | XFREE (MTYPE_LEX, $1); | |
251 | } | |
252 | | IPV6_PREFIX | |
253 | { | |
254 | $$ = new_token_node (ctx, IPV6_PREFIX_TKN, $1, doc_next(ctx)); | |
255 | XFREE (MTYPE_LEX, $1); | |
256 | } | |
257 | | VARIABLE | |
258 | { | |
259 | $$ = new_token_node (ctx, VARIABLE_TKN, $1, doc_next(ctx)); | |
260 | XFREE (MTYPE_LEX, $1); | |
261 | } | |
262 | | RANGE | |
263 | { | |
264 | $$ = new_token_node (ctx, RANGE_TKN, $1, doc_next(ctx)); | |
265 | struct cmd_token *token = $$->data; | |
266 | ||
267 | // get the numbers out | |
268 | yylval.string++; | |
269 | token->min = strtoll (yylval.string, &yylval.string, 10); | |
270 | strsep (&yylval.string, "-"); | |
271 | token->max = strtoll (yylval.string, &yylval.string, 10); | |
272 | ||
273 | // validate range | |
274 | if (token->min > token->max) cmd_yyerror (&@1, ctx, "Invalid range."); | |
275 | ||
276 | XFREE (MTYPE_LEX, $1); | |
277 | } | |
278 | | MAC | |
279 | { | |
280 | $$ = new_token_node (ctx, MAC_TKN, $1, doc_next(ctx)); | |
281 | XFREE (MTYPE_LEX, $1); | |
282 | } | |
283 | | MAC_PREFIX | |
284 | { | |
285 | $$ = new_token_node (ctx, MAC_PREFIX_TKN, $1, doc_next(ctx)); | |
286 | XFREE (MTYPE_LEX, $1); | |
287 | } | |
288 | ||
289 | placeholder_token: | |
290 | placeholder_token_real varname_token | |
291 | { | |
292 | struct cmd_token *token = $$->data; | |
293 | $$ = $1; | |
294 | cmd_token_varname_set (token, $2); | |
295 | XFREE (MTYPE_LEX, $2); | |
296 | }; | |
297 | ||
298 | ||
299 | /* <selector|set> productions */ | |
300 | selector: '<' selector_seq_seq '>' varname_token | |
301 | { | |
302 | $$ = $2; | |
303 | cmd_token_varname_set ($2.end->data, $4); | |
304 | XFREE (MTYPE_LEX, $4); | |
305 | }; | |
306 | ||
307 | selector_seq_seq: | |
308 | selector_seq_seq '|' selector_token_seq | |
309 | { | |
310 | $$ = $1; | |
311 | graph_add_edge ($$.start, $3.start); | |
312 | graph_add_edge ($3.end, $$.end); | |
313 | } | |
314 | | selector_token_seq | |
315 | { | |
316 | $$.start = new_token_node (ctx, FORK_TKN, NULL, NULL); | |
317 | $$.end = new_token_node (ctx, JOIN_TKN, NULL, NULL); | |
318 | ((struct cmd_token *)$$.start->data)->forkjoin = $$.end; | |
319 | ((struct cmd_token *)$$.end->data)->forkjoin = $$.start; | |
320 | ||
321 | graph_add_edge ($$.start, $1.start); | |
322 | graph_add_edge ($1.end, $$.end); | |
323 | } | |
324 | ; | |
325 | ||
326 | /* {keyword} productions */ | |
327 | selector: '{' selector_seq_seq '}' varname_token | |
328 | { | |
329 | $$ = $2; | |
330 | graph_add_edge ($$.end, $$.start); | |
331 | /* there is intentionally no start->end link, for two reasons: | |
332 | * 1) this allows "at least 1 of" semantics, which are otherwise impossible | |
333 | * 2) this would add a start->end->start loop in the graph that the current | |
334 | * loop-avoidal fails to handle | |
335 | * just use [{a|b}] if neccessary, that will work perfectly fine, and reason | |
336 | * #1 is good enough to keep it this way. */ | |
337 | ||
338 | cmd_token_varname_set ($2.end->data, $4); | |
339 | XFREE (MTYPE_LEX, $4); | |
340 | }; | |
341 | ||
342 | ||
343 | selector_token: | |
344 | simple_token | |
345 | { | |
346 | $$.start = $$.end = $1; | |
347 | } | |
348 | | selector | |
349 | ; | |
350 | ||
351 | selector_token_seq: | |
352 | selector_token_seq selector_token | |
353 | { | |
354 | graph_add_edge ($1.end, $2.start); | |
355 | $$.start = $1.start; | |
356 | $$.end = $2.end; | |
357 | } | |
358 | | selector_token | |
359 | ; | |
360 | ||
361 | /* [option] productions */ | |
362 | selector: '[' selector_seq_seq ']' varname_token | |
363 | { | |
364 | $$ = $2; | |
365 | graph_add_edge ($$.start, $$.end); | |
366 | cmd_token_varname_set ($2.end->data, $4); | |
367 | XFREE (MTYPE_LEX, $4); | |
368 | } | |
369 | ; | |
370 | ||
371 | %% | |
372 | ||
373 | #undef scanner | |
374 | ||
375 | DEFINE_MTYPE(LIB, LEX, "Lexer token (temporary)") | |
376 | ||
377 | void | |
378 | cmd_graph_parse (struct graph *graph, struct cmd_element *cmd) | |
379 | { | |
380 | struct parser_ctx ctx = { .graph = graph, .el = cmd }; | |
381 | ||
382 | // set to 1 to enable parser traces | |
383 | yydebug = 0; | |
384 | ||
385 | set_lexer_string (&ctx.scanner, cmd->string); | |
386 | ||
387 | // parse command into DFA | |
388 | cmd_yyparse (&ctx); | |
389 | ||
390 | /* cleanup lexer */ | |
391 | cleanup_lexer (&ctx.scanner); | |
392 | ||
393 | // cleanup | |
394 | cleanup (&ctx); | |
395 | } | |
396 | ||
397 | /* parser helper functions */ | |
398 | ||
399 | void | |
400 | yyerror (CMD_YYLTYPE *loc, struct parser_ctx *ctx, char const *msg) | |
401 | { | |
402 | char *tmpstr = strdup(ctx->el->string); | |
403 | char *line, *eol; | |
404 | char spacing[256]; | |
405 | int lineno = 0; | |
406 | ||
407 | zlog_notice ("%s: FATAL parse error: %s", __func__, msg); | |
408 | zlog_notice ("%s: %d:%d-%d of this command definition:", __func__, loc->first_line, loc->first_column, loc->last_column); | |
409 | ||
410 | line = tmpstr; | |
411 | do { | |
412 | lineno++; | |
413 | eol = strchr(line, '\n'); | |
414 | if (eol) | |
415 | *eol++ = '\0'; | |
416 | ||
417 | zlog_notice ("%s: | %s", __func__, line); | |
418 | if (lineno == loc->first_line && lineno == loc->last_line | |
419 | && loc->first_column < (int)sizeof(spacing) - 1 | |
420 | && loc->last_column < (int)sizeof(spacing) - 1) { | |
421 | ||
422 | int len = loc->last_column - loc->first_column; | |
423 | if (len == 0) | |
424 | len = 1; | |
425 | ||
426 | memset(spacing, ' ', loc->first_column - 1); | |
427 | memset(spacing + loc->first_column - 1, '^', len); | |
428 | spacing[loc->first_column - 1 + len] = '\0'; | |
429 | zlog_notice ("%s: | %s", __func__, spacing); | |
430 | } | |
431 | } while ((line = eol)); | |
432 | free(tmpstr); | |
433 | } | |
434 | ||
435 | static void | |
436 | cleanup (struct parser_ctx *ctx) | |
437 | { | |
438 | /* free resources */ | |
439 | free (ctx->docstr_start); | |
440 | ||
441 | /* clear state pointers */ | |
442 | ctx->currnode = NULL; | |
443 | ctx->docstr_start = ctx->docstr = NULL; | |
444 | } | |
445 | ||
446 | static void | |
447 | terminate_graph (CMD_YYLTYPE *locp, struct parser_ctx *ctx, | |
448 | struct graph_node *finalnode) | |
449 | { | |
450 | // end of graph should look like this | |
451 | // * -> finalnode -> END_TKN -> cmd_element | |
452 | struct cmd_element *element = ctx->el; | |
453 | struct graph_node *end_token_node = | |
454 | new_token_node (ctx, END_TKN, CMD_CR_TEXT, ""); | |
455 | struct graph_node *end_element_node = | |
456 | graph_new_node (ctx->graph, element, NULL); | |
457 | ||
458 | if (ctx->docstr && strlen (ctx->docstr) > 1) { | |
459 | zlog_debug ("Excessive docstring while parsing '%s'", ctx->el->string); | |
460 | zlog_debug ("----------"); | |
461 | while (ctx->docstr && ctx->docstr[1] != '\0') | |
462 | zlog_debug ("%s", strsep(&ctx->docstr, "\n")); | |
463 | zlog_debug ("----------\n"); | |
464 | } | |
465 | ||
466 | graph_add_edge (finalnode, end_token_node); | |
467 | graph_add_edge (end_token_node, end_element_node); | |
468 | } | |
469 | ||
470 | static const char * | |
471 | doc_next (struct parser_ctx *ctx) | |
472 | { | |
473 | const char *piece = ctx->docstr ? strsep (&ctx->docstr, "\n") : ""; | |
474 | if (*piece == 0x03) | |
475 | { | |
476 | zlog_debug ("Ran out of docstring while parsing '%s'", ctx->el->string); | |
477 | piece = ""; | |
478 | } | |
479 | ||
480 | return piece; | |
481 | } | |
482 | ||
483 | static struct graph_node * | |
484 | new_token_node (struct parser_ctx *ctx, enum cmd_token_type type, | |
485 | const char *text, const char *doc) | |
486 | { | |
487 | struct cmd_token *token = cmd_token_new (type, ctx->el->attr, text, doc); | |
488 | return graph_new_node (ctx->graph, token, (void (*)(void *)) &cmd_token_del); | |
489 | } |