2 * Command format string parser for CLI backend.
5 * Copyright (C) 2016 Cumulus Networks, Inc.
7 * This file is part of GNU Zebra.
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
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.
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
26 // compile with debugging facilities
31 /* define parse.error verbose */
33 /* define api.prefix {cmd_yy} */
35 /* names for generated header and parser files */
36 %defines "lib/command_parse.h"
37 %output "lib/command_parse.c"
39 /* note: code blocks are output in order, to both .c and .h:
41 * 2. %union + bison forward decls
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.
54 #include "command_graph.h"
59 #define YYSTYPE CMD_YYSTYPE
60 #define YYLTYPE CMD_YYLTYPE
63 /* subgraph semantic value */
65 struct graph_node *start, *end;
72 struct graph_node *node;
73 struct subgraph subgraph;
78 #include "command_lex.h"
81 extern void set_lexer_string (yyscan_t *scn, const char *string);
82 extern void cleanup_lexer (yyscan_t *scn);
87 const struct cmd_element *el;
90 struct graph_node *currnode;
92 /* pointers to copy of command docstring */
93 char *docstr_start, *docstr;
97 /* union types for lexed tokens */
100 %token <string> IPV4_PREFIX
102 %token <string> IPV6_PREFIX
103 %token <string> VARIABLE
104 %token <string> RANGE
106 %token <string> MAC_PREFIX
108 /* union types for parsed rules */
110 %type <node> literal_token
111 %type <node> placeholder_token
112 %type <node> placeholder_token_real
113 %type <node> simple_token
114 %type <subgraph> selector
115 %type <subgraph> selector_token
116 %type <subgraph> selector_token_seq
117 %type <subgraph> selector_seq_seq
119 %type <string> varname_token
123 /* bison declarations */
125 cmd_yyerror (CMD_YYLTYPE *locp, struct parser_ctx *ctx, char const *msg);
127 /* helper functions for parser */
129 doc_next (struct parser_ctx *ctx);
131 static struct graph_node *
132 new_token_node (struct parser_ctx *,
133 enum cmd_token_type type,
138 terminate_graph (CMD_YYLTYPE *locp, struct parser_ctx *ctx,
139 struct graph_node *);
142 cleanup (struct parser_ctx *ctx);
144 static void loopcheck(struct parser_ctx *ctx, struct subgraph *sg);
146 #define scanner ctx->scanner
149 /* yyparse parameters */
150 %lex-param {yyscan_t scanner}
151 %parse-param {struct parser_ctx *ctx}
153 /* called automatically before yyparse */
155 /* clear state pointers */
156 ctx->currnode = vector_slot (ctx->graph->nodes, 0);
158 /* copy docstring and keep a pointer to the copy */
161 // allocate a new buffer, making room for a flag
162 size_t length = (size_t) strlen (ctx->el->doc) + 2;
163 ctx->docstr = malloc (length);
164 memcpy (ctx->docstr, ctx->el->doc, strlen (ctx->el->doc));
165 // set the flag so doc_next knows when to print a warning
166 ctx->docstr[length - 2] = 0x03;
168 ctx->docstr[length - 1] = 0x00;
170 ctx->docstr_start = ctx->docstr;
178 // tack on the command element
179 terminate_graph (&@1, ctx, ctx->currnode);
181 | cmd_token_seq placeholder_token '.' '.' '.'
183 if ((ctx->currnode = graph_add_edge (ctx->currnode, $2)) != $2)
184 graph_delete_node (ctx->graph, $2);
186 ((struct cmd_token *)ctx->currnode->data)->allowrepeat = 1;
188 // adding a node as a child of itself accepts any number
189 // of the same token, which is what we want for variadics
190 graph_add_edge (ctx->currnode, ctx->currnode);
192 // tack on the command element
193 terminate_graph (&@1, ctx, ctx->currnode);
197 varname_token: '$' WORD
209 | cmd_token_seq cmd_token
215 if ((ctx->currnode = graph_add_edge (ctx->currnode, $1)) != $1)
216 graph_delete_node (ctx->graph, $1);
220 graph_add_edge (ctx->currnode, $1.start);
221 ctx->currnode = $1.end;
230 literal_token: WORD varname_token
232 $$ = new_token_node (ctx, WORD_TKN, $1, doc_next(ctx));
233 cmd_token_varname_set ($$->data, $2);
234 XFREE (MTYPE_LEX, $2);
235 XFREE (MTYPE_LEX, $1);
239 placeholder_token_real:
242 $$ = new_token_node (ctx, IPV4_TKN, $1, doc_next(ctx));
243 XFREE (MTYPE_LEX, $1);
247 $$ = new_token_node (ctx, IPV4_PREFIX_TKN, $1, doc_next(ctx));
248 XFREE (MTYPE_LEX, $1);
252 $$ = new_token_node (ctx, IPV6_TKN, $1, doc_next(ctx));
253 XFREE (MTYPE_LEX, $1);
257 $$ = new_token_node (ctx, IPV6_PREFIX_TKN, $1, doc_next(ctx));
258 XFREE (MTYPE_LEX, $1);
262 $$ = new_token_node (ctx, VARIABLE_TKN, $1, doc_next(ctx));
263 XFREE (MTYPE_LEX, $1);
267 $$ = new_token_node (ctx, RANGE_TKN, $1, doc_next(ctx));
268 struct cmd_token *token = $$->data;
270 // get the numbers out
272 token->min = strtoll (yylval.string, &yylval.string, 10);
273 strsep (&yylval.string, "-");
274 token->max = strtoll (yylval.string, &yylval.string, 10);
277 if (token->min > token->max) cmd_yyerror (&@1, ctx, "Invalid range.");
279 XFREE (MTYPE_LEX, $1);
283 $$ = new_token_node (ctx, MAC_TKN, $1, doc_next(ctx));
284 XFREE (MTYPE_LEX, $1);
288 $$ = new_token_node (ctx, MAC_PREFIX_TKN, $1, doc_next(ctx));
289 XFREE (MTYPE_LEX, $1);
293 placeholder_token_real varname_token
295 struct cmd_token *token = $$->data;
297 cmd_token_varname_set (token, $2);
298 XFREE (MTYPE_LEX, $2);
302 /* <selector|set> productions */
303 selector: '<' selector_seq_seq '>' varname_token
306 cmd_token_varname_set ($2.end->data, $4);
307 XFREE (MTYPE_LEX, $4);
311 selector_seq_seq '|' selector_token_seq
314 graph_add_edge ($$.start, $3.start);
315 graph_add_edge ($3.end, $$.end);
319 $$.start = new_token_node (ctx, FORK_TKN, NULL, NULL);
320 $$.end = new_token_node (ctx, JOIN_TKN, NULL, NULL);
321 ((struct cmd_token *)$$.start->data)->forkjoin = $$.end;
322 ((struct cmd_token *)$$.end->data)->forkjoin = $$.start;
324 graph_add_edge ($$.start, $1.start);
325 graph_add_edge ($1.end, $$.end);
329 /* {keyword} productions */
330 selector: '{' selector_seq_seq '}' varname_token
333 graph_add_edge ($$.end, $$.start);
334 /* there is intentionally no start->end link, for two reasons:
335 * 1) this allows "at least 1 of" semantics, which are otherwise impossible
336 * 2) this would add a start->end->start loop in the graph that the current
337 * loop-avoidal fails to handle
338 * just use [{a|b}] if neccessary, that will work perfectly fine, and reason
339 * #1 is good enough to keep it this way. */
342 cmd_token_varname_set ($2.end->data, $4);
343 XFREE (MTYPE_LEX, $4);
350 $$.start = $$.end = $1;
356 selector_token_seq selector_token
358 graph_add_edge ($1.end, $2.start);
365 /* [option] productions */
366 selector: '[' selector_seq_seq ']' varname_token
369 graph_add_edge ($$.start, $$.end);
370 cmd_token_varname_set ($2.end->data, $4);
371 XFREE (MTYPE_LEX, $4);
379 DEFINE_MTYPE(LIB, LEX, "Lexer token (temporary)")
382 cmd_graph_parse (struct graph *graph, const struct cmd_element *cmd)
384 struct parser_ctx ctx = { .graph = graph, .el = cmd };
386 // set to 1 to enable parser traces
389 set_lexer_string (&ctx.scanner, cmd->string);
391 // parse command into DFA
395 cleanup_lexer (&ctx.scanner);
401 /* parser helper functions */
403 static bool loopcheck_inner(struct graph_node *start, struct graph_node *node,
404 struct graph_node *end, size_t depth)
413 for (i = 0; i < vector_active(node->to); i++) {
414 struct graph_node *next = vector_slot(node->to, i);
415 struct cmd_token *tok = next->data;
417 if (next == end || next == start)
419 if (tok->type < SPECIAL_TKN)
421 ret = loopcheck_inner(start, next, end, depth);
428 static void loopcheck(struct parser_ctx *ctx, struct subgraph *sg)
430 if (loopcheck_inner(sg->start, sg->start, sg->end, 0))
431 zlog_err("FATAL: '%s': {} contains an empty path! Use [{...}]",
436 yyerror (CMD_YYLTYPE *loc, struct parser_ctx *ctx, char const *msg)
438 char *tmpstr = strdup(ctx->el->string);
443 zlog_notice ("%s: FATAL parse error: %s", __func__, msg);
444 zlog_notice ("%s: %d:%d-%d of this command definition:", __func__, loc->first_line, loc->first_column, loc->last_column);
449 eol = strchr(line, '\n');
453 zlog_notice ("%s: | %s", __func__, line);
454 if (lineno == loc->first_line && lineno == loc->last_line
455 && loc->first_column < (int)sizeof(spacing) - 1
456 && loc->last_column < (int)sizeof(spacing) - 1) {
458 int len = loc->last_column - loc->first_column;
462 memset(spacing, ' ', loc->first_column - 1);
463 memset(spacing + loc->first_column - 1, '^', len);
464 spacing[loc->first_column - 1 + len] = '\0';
465 zlog_notice ("%s: | %s", __func__, spacing);
467 } while ((line = eol));
472 cleanup (struct parser_ctx *ctx)
475 free (ctx->docstr_start);
477 /* clear state pointers */
478 ctx->currnode = NULL;
479 ctx->docstr_start = ctx->docstr = NULL;
483 terminate_graph (CMD_YYLTYPE *locp, struct parser_ctx *ctx,
484 struct graph_node *finalnode)
486 // end of graph should look like this
487 // * -> finalnode -> END_TKN -> cmd_element
488 const struct cmd_element *element = ctx->el;
489 struct graph_node *end_token_node =
490 new_token_node (ctx, END_TKN, CMD_CR_TEXT, "");
491 struct graph_node *end_element_node =
492 graph_new_node (ctx->graph, (void *)element, NULL);
494 if (ctx->docstr && strlen (ctx->docstr) > 1) {
495 zlog_err ("Excessive docstring while parsing '%s'", ctx->el->string);
496 zlog_err ("----------");
497 while (ctx->docstr && ctx->docstr[1] != '\0')
498 zlog_err ("%s", strsep(&ctx->docstr, "\n"));
499 zlog_err ("----------\n");
502 graph_add_edge (finalnode, end_token_node);
503 graph_add_edge (end_token_node, end_element_node);
507 doc_next (struct parser_ctx *ctx)
509 const char *piece = ctx->docstr ? strsep (&ctx->docstr, "\n") : "";
512 zlog_err ("Ran out of docstring while parsing '%s'", ctx->el->string);
519 static struct graph_node *
520 new_token_node (struct parser_ctx *ctx, enum cmd_token_type type,
521 const char *text, const char *doc)
523 struct cmd_token *token = cmd_token_new (type, ctx->el->attr, text, doc);
524 return graph_new_node (ctx->graph, token, (void (*)(void *)) &cmd_token_del);