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fd79ecee DJ |
1 | /* Helper routines for parsing XML using Expat. |
2 | ||
6aba47ca | 3 | Copyright (C) 2006, 2007 Free Software Foundation, Inc. |
fd79ecee DJ |
4 | |
5 | This file is part of GDB. | |
6 | ||
7 | This program is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 2 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | This program is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with this program; if not, write to the Free Software | |
19 | Foundation, Inc., 51 Franklin Street, Fifth Floor, | |
20 | Boston, MA 02110-1301, USA. */ | |
21 | ||
22 | #include "defs.h" | |
e776119f DJ |
23 | #include "gdbcmd.h" |
24 | ||
25 | /* Debugging flag. */ | |
26 | static int debug_xml; | |
fd79ecee DJ |
27 | |
28 | /* The contents of this file are only useful if XML support is | |
29 | available. */ | |
30 | #ifdef HAVE_LIBEXPAT | |
31 | ||
32 | #include "exceptions.h" | |
33 | #include "xml-support.h" | |
34 | ||
dbc981de | 35 | #include "gdb_expat.h" |
fd79ecee | 36 | #include "gdb_string.h" |
e776119f DJ |
37 | #include "safe-ctype.h" |
38 | ||
39 | /* A parsing level -- used to keep track of the current element | |
40 | nesting. */ | |
41 | struct scope_level | |
42 | { | |
43 | /* Elements we allow at this level. */ | |
44 | const struct gdb_xml_element *elements; | |
45 | ||
46 | /* The element which we are within. */ | |
47 | const struct gdb_xml_element *element; | |
48 | ||
49 | /* Mask of which elements we've seen at this level (used for | |
50 | optional and repeatable checking). */ | |
51 | unsigned int seen; | |
52 | ||
53 | /* Body text accumulation. */ | |
54 | struct obstack *body; | |
55 | }; | |
56 | typedef struct scope_level scope_level_s; | |
57 | DEF_VEC_O(scope_level_s); | |
58 | ||
59 | /* The parser itself, and our additional state. */ | |
60 | struct gdb_xml_parser | |
61 | { | |
62 | XML_Parser expat_parser; /* The underlying expat parser. */ | |
63 | ||
64 | const char *name; /* Name of this parser. */ | |
65 | void *user_data; /* The user's callback data, for handlers. */ | |
66 | ||
67 | VEC(scope_level_s) *scopes; /* Scoping stack. */ | |
68 | ||
69 | struct gdb_exception error; /* A thrown error, if any. */ | |
70 | int last_line; /* The line of the thrown error, or 0. */ | |
71 | }; | |
72 | ||
73 | /* Process some body text. We accumulate the text for later use; it's | |
74 | wrong to do anything with it immediately, because a single block of | |
75 | text might be broken up into multiple calls to this function. */ | |
76 | ||
77 | static void | |
78 | gdb_xml_body_text (void *data, const XML_Char *text, int length) | |
79 | { | |
80 | struct gdb_xml_parser *parser = data; | |
81 | struct scope_level *scope = VEC_last (scope_level_s, parser->scopes); | |
82 | ||
ca4ca11e DJ |
83 | if (parser->error.reason < 0) |
84 | return; | |
85 | ||
e776119f DJ |
86 | if (scope->body == NULL) |
87 | { | |
88 | scope->body = XZALLOC (struct obstack); | |
89 | obstack_init (scope->body); | |
90 | } | |
91 | ||
92 | obstack_grow (scope->body, text, length); | |
93 | } | |
fd79ecee | 94 | |
e776119f | 95 | /* Issue a debugging message from one of PARSER's handlers. */ |
fd79ecee | 96 | |
e776119f DJ |
97 | void |
98 | gdb_xml_debug (struct gdb_xml_parser *parser, const char *format, ...) | |
99 | { | |
100 | int line = XML_GetCurrentLineNumber (parser->expat_parser); | |
101 | va_list ap; | |
102 | char *message; | |
103 | ||
104 | if (!debug_xml) | |
105 | return; | |
106 | ||
107 | va_start (ap, format); | |
108 | message = xstrvprintf (format, ap); | |
109 | if (line) | |
110 | fprintf_unfiltered (gdb_stderr, "%s (line %d): %s\n", | |
111 | parser->name, line, message); | |
112 | else | |
113 | fprintf_unfiltered (gdb_stderr, "%s: %s\n", | |
114 | parser->name, message); | |
115 | xfree (message); | |
116 | } | |
117 | ||
118 | /* Issue an error message from one of PARSER's handlers, and stop | |
119 | parsing. */ | |
120 | ||
121 | void | |
122 | gdb_xml_error (struct gdb_xml_parser *parser, const char *format, ...) | |
123 | { | |
124 | int line = XML_GetCurrentLineNumber (parser->expat_parser); | |
125 | va_list ap; | |
126 | ||
127 | parser->last_line = line; | |
128 | va_start (ap, format); | |
129 | throw_verror (XML_PARSE_ERROR, format, ap); | |
130 | } | |
131 | ||
132 | /* Clean up a vector of parsed attribute values. */ | |
133 | ||
134 | static void | |
135 | gdb_xml_values_cleanup (void *data) | |
136 | { | |
137 | VEC(gdb_xml_value_s) **values = data; | |
138 | struct gdb_xml_value *value; | |
139 | int ix; | |
140 | ||
141 | for (ix = 0; VEC_iterate (gdb_xml_value_s, *values, ix, value); ix++) | |
142 | xfree (value->value); | |
143 | VEC_free (gdb_xml_value_s, *values); | |
144 | } | |
145 | ||
146 | /* Handle the start of an element. DATA is our local XML parser, NAME | |
147 | is the element, and ATTRS are the names and values of this | |
148 | element's attributes. */ | |
149 | ||
150 | static void | |
151 | gdb_xml_start_element (void *data, const XML_Char *name, | |
152 | const XML_Char **attrs) | |
fd79ecee | 153 | { |
e776119f DJ |
154 | struct gdb_xml_parser *parser = data; |
155 | struct scope_level *scope = VEC_last (scope_level_s, parser->scopes); | |
156 | struct scope_level new_scope; | |
157 | const struct gdb_xml_element *element; | |
158 | const struct gdb_xml_attribute *attribute; | |
159 | VEC(gdb_xml_value_s) *attributes = NULL; | |
160 | unsigned int seen; | |
161 | struct cleanup *back_to; | |
162 | ||
163 | back_to = make_cleanup (gdb_xml_values_cleanup, &attributes); | |
164 | ||
165 | /* Push an error scope. If we return or throw an exception before | |
166 | filling this in, it will tell us to ignore children of this | |
167 | element. */ | |
168 | memset (&new_scope, 0, sizeof (new_scope)); | |
169 | VEC_safe_push (scope_level_s, parser->scopes, &new_scope); | |
170 | ||
171 | gdb_xml_debug (parser, _("Entering element <%s>"), name); | |
172 | ||
173 | /* Find this element in the list of the current scope's allowed | |
174 | children. Record that we've seen it. */ | |
175 | ||
176 | seen = 1; | |
177 | for (element = scope->elements; element && element->name; | |
178 | element++, seen <<= 1) | |
179 | if (strcmp (element->name, name) == 0) | |
180 | break; | |
181 | ||
182 | if (element == NULL || element->name == NULL) | |
183 | { | |
184 | gdb_xml_debug (parser, _("Element <%s> unknown"), name); | |
185 | do_cleanups (back_to); | |
186 | return; | |
187 | } | |
188 | ||
189 | if (!(element->flags & GDB_XML_EF_REPEATABLE) && (seen & scope->seen)) | |
190 | gdb_xml_error (parser, _("Element <%s> only expected once"), name); | |
191 | ||
192 | scope->seen |= seen; | |
193 | ||
194 | for (attribute = element->attributes; | |
195 | attribute != NULL && attribute->name != NULL; | |
196 | attribute++) | |
197 | { | |
198 | const char *val = NULL; | |
199 | const XML_Char **p; | |
200 | void *parsed_value; | |
201 | struct gdb_xml_value new_value; | |
202 | ||
203 | for (p = attrs; *p != NULL; p += 2) | |
204 | if (!strcmp (attribute->name, p[0])) | |
205 | { | |
206 | val = p[1]; | |
207 | break; | |
208 | } | |
209 | ||
210 | if (*p != NULL && val == NULL) | |
211 | { | |
212 | gdb_xml_debug (parser, _("Attribute \"%s\" missing a value"), | |
213 | attribute->name); | |
214 | continue; | |
215 | } | |
216 | ||
217 | if (*p == NULL && !(attribute->flags & GDB_XML_AF_OPTIONAL)) | |
218 | { | |
219 | gdb_xml_error (parser, _("Required attribute \"%s\" of " | |
220 | "<%s> not specified"), | |
221 | attribute->name, element->name); | |
222 | continue; | |
223 | } | |
224 | ||
225 | if (*p == NULL) | |
226 | continue; | |
227 | ||
228 | gdb_xml_debug (parser, _("Parsing attribute %s=\"%s\""), | |
229 | attribute->name, val); | |
230 | ||
231 | if (attribute->handler) | |
232 | parsed_value = attribute->handler (parser, attribute, val); | |
233 | else | |
234 | parsed_value = xstrdup (val); | |
235 | ||
236 | new_value.name = attribute->name; | |
237 | new_value.value = parsed_value; | |
238 | VEC_safe_push (gdb_xml_value_s, attributes, &new_value); | |
239 | } | |
240 | ||
241 | /* Check for unrecognized attributes. */ | |
242 | if (debug_xml) | |
fd79ecee | 243 | { |
e776119f DJ |
244 | const XML_Char **p; |
245 | ||
246 | for (p = attrs; *p != NULL; p += 2) | |
247 | { | |
248 | for (attribute = element->attributes; | |
249 | attribute != NULL && attribute->name != NULL; | |
250 | attribute++) | |
251 | if (strcmp (attribute->name, *p) == 0) | |
252 | break; | |
253 | ||
254 | if (attribute == NULL || attribute->name == NULL) | |
255 | gdb_xml_debug (parser, _("Ignoring unknown attribute %s"), *p); | |
256 | } | |
257 | } | |
258 | ||
259 | /* Call the element handler if there is one. */ | |
260 | if (element->start_handler) | |
261 | element->start_handler (parser, element, parser->user_data, attributes); | |
262 | ||
263 | /* Fill in a new scope level. */ | |
264 | scope = VEC_last (scope_level_s, parser->scopes); | |
265 | scope->element = element; | |
266 | scope->elements = element->children; | |
267 | ||
268 | do_cleanups (back_to); | |
269 | } | |
270 | ||
271 | /* Wrapper for gdb_xml_start_element, to prevent throwing exceptions | |
272 | through expat. */ | |
273 | ||
274 | static void | |
275 | gdb_xml_start_element_wrapper (void *data, const XML_Char *name, | |
276 | const XML_Char **attrs) | |
277 | { | |
278 | struct gdb_xml_parser *parser = data; | |
279 | volatile struct gdb_exception ex; | |
280 | ||
281 | if (parser->error.reason < 0) | |
282 | return; | |
fd79ecee | 283 | |
e776119f DJ |
284 | TRY_CATCH (ex, RETURN_MASK_ALL) |
285 | { | |
286 | gdb_xml_start_element (data, name, attrs); | |
287 | } | |
288 | if (ex.reason < 0) | |
289 | { | |
290 | parser->error = ex; | |
ca4ca11e | 291 | #ifdef HAVE_XML_STOPPARSER |
e776119f | 292 | XML_StopParser (parser->expat_parser, XML_FALSE); |
ca4ca11e | 293 | #endif |
fd79ecee | 294 | } |
e776119f DJ |
295 | } |
296 | ||
297 | /* Handle the end of an element. DATA is our local XML parser, and | |
298 | NAME is the current element. */ | |
299 | ||
300 | static void | |
301 | gdb_xml_end_element (void *data, const XML_Char *name) | |
302 | { | |
303 | struct gdb_xml_parser *parser = data; | |
304 | struct scope_level *scope = VEC_last (scope_level_s, parser->scopes); | |
305 | const struct gdb_xml_element *element; | |
306 | unsigned int seen; | |
307 | char *body; | |
308 | ||
309 | gdb_xml_debug (parser, _("Leaving element <%s>"), name); | |
310 | ||
311 | for (element = scope->elements, seen = 1; | |
312 | element != NULL && element->name != NULL; | |
313 | element++, seen <<= 1) | |
314 | if ((scope->seen & seen) == 0 | |
315 | && (element->flags & GDB_XML_EF_OPTIONAL) == 0) | |
d097fa3e | 316 | gdb_xml_error (parser, _("Required element <%s> is missing"), |
e776119f DJ |
317 | element->name); |
318 | ||
319 | /* Call the element processor. */ | |
320 | if (scope->body == NULL) | |
321 | body = ""; | |
322 | else | |
323 | { | |
324 | int length; | |
325 | ||
326 | length = obstack_object_size (scope->body); | |
327 | obstack_1grow (scope->body, '\0'); | |
328 | body = obstack_finish (scope->body); | |
329 | ||
330 | /* Strip leading and trailing whitespace. */ | |
331 | while (length > 0 && ISSPACE (body[length-1])) | |
332 | body[--length] = '\0'; | |
333 | while (*body && ISSPACE (*body)) | |
334 | body++; | |
335 | } | |
336 | ||
337 | if (scope->element != NULL && scope->element->end_handler) | |
338 | scope->element->end_handler (parser, scope->element, parser->user_data, | |
339 | body); | |
340 | ||
341 | /* Pop the scope level. */ | |
342 | if (scope->body) | |
343 | { | |
344 | obstack_free (scope->body, NULL); | |
345 | xfree (scope->body); | |
346 | } | |
347 | VEC_pop (scope_level_s, parser->scopes); | |
348 | } | |
349 | ||
350 | /* Wrapper for gdb_xml_end_element, to prevent throwing exceptions | |
351 | through expat. */ | |
352 | ||
353 | static void | |
354 | gdb_xml_end_element_wrapper (void *data, const XML_Char *name) | |
355 | { | |
356 | struct gdb_xml_parser *parser = data; | |
357 | volatile struct gdb_exception ex; | |
358 | ||
359 | if (parser->error.reason < 0) | |
360 | return; | |
361 | ||
362 | TRY_CATCH (ex, RETURN_MASK_ALL) | |
363 | { | |
364 | gdb_xml_end_element (data, name); | |
365 | } | |
366 | if (ex.reason < 0) | |
367 | { | |
368 | parser->error = ex; | |
ca4ca11e | 369 | #ifdef HAVE_XML_STOPPARSER |
e776119f | 370 | XML_StopParser (parser->expat_parser, XML_FALSE); |
ca4ca11e | 371 | #endif |
e776119f DJ |
372 | } |
373 | } | |
374 | ||
375 | /* Free a parser and all its associated state. */ | |
376 | ||
377 | static void | |
378 | gdb_xml_cleanup (void *arg) | |
379 | { | |
380 | struct gdb_xml_parser *parser = arg; | |
381 | struct scope_level *scope; | |
382 | int ix; | |
383 | ||
384 | XML_ParserFree (parser->expat_parser); | |
385 | ||
386 | /* Clean up the scopes. */ | |
387 | for (ix = 0; VEC_iterate (scope_level_s, parser->scopes, ix, scope); ix++) | |
388 | if (scope->body) | |
389 | { | |
390 | obstack_free (scope->body, NULL); | |
391 | xfree (scope->body); | |
392 | } | |
393 | VEC_free (scope_level_s, parser->scopes); | |
394 | ||
395 | xfree (parser); | |
396 | } | |
397 | ||
398 | /* Initialize and return a parser. Register a cleanup to destroy the | |
399 | parser. */ | |
400 | ||
401 | struct gdb_xml_parser * | |
402 | gdb_xml_create_parser_and_cleanup (const char *name, | |
403 | const struct gdb_xml_element *elements, | |
404 | void *user_data) | |
405 | { | |
406 | struct gdb_xml_parser *parser; | |
407 | struct scope_level start_scope; | |
408 | ||
409 | /* Initialize the parser. */ | |
410 | parser = XZALLOC (struct gdb_xml_parser); | |
411 | parser->expat_parser = XML_ParserCreateNS (NULL, '!'); | |
412 | if (parser->expat_parser == NULL) | |
413 | { | |
414 | xfree (parser); | |
415 | nomem (0); | |
416 | } | |
417 | ||
418 | parser->name = name; | |
419 | ||
420 | parser->user_data = user_data; | |
421 | XML_SetUserData (parser->expat_parser, parser); | |
422 | ||
423 | /* Set the callbacks. */ | |
424 | XML_SetElementHandler (parser->expat_parser, gdb_xml_start_element_wrapper, | |
425 | gdb_xml_end_element_wrapper); | |
426 | XML_SetCharacterDataHandler (parser->expat_parser, gdb_xml_body_text); | |
427 | ||
428 | /* Initialize the outer scope. */ | |
429 | memset (&start_scope, 0, sizeof (start_scope)); | |
430 | start_scope.elements = elements; | |
431 | VEC_safe_push (scope_level_s, parser->scopes, &start_scope); | |
432 | ||
433 | make_cleanup (gdb_xml_cleanup, parser); | |
434 | ||
435 | return parser; | |
436 | } | |
437 | ||
438 | /* Invoke PARSER on BUFFER. BUFFER is the data to parse, which | |
439 | should be NUL-terminated. | |
440 | ||
441 | The return value is 0 for success or -1 for error. It may throw, | |
442 | but only if something unexpected goes wrong during parsing; parse | |
443 | errors will be caught, warned about, and reported as failure. */ | |
444 | ||
445 | int | |
446 | gdb_xml_parse (struct gdb_xml_parser *parser, const char *buffer) | |
447 | { | |
448 | enum XML_Status status; | |
449 | const char *error_string; | |
450 | ||
451 | status = XML_Parse (parser->expat_parser, buffer, strlen (buffer), 1); | |
452 | ||
453 | if (status == XML_STATUS_OK && parser->error.reason == 0) | |
454 | return 0; | |
455 | ||
456 | if (parser->error.reason == RETURN_ERROR | |
457 | && parser->error.error == XML_PARSE_ERROR) | |
458 | { | |
459 | gdb_assert (parser->error.message != NULL); | |
460 | error_string = parser->error.message; | |
461 | } | |
462 | else if (status == XML_STATUS_ERROR) | |
463 | { | |
464 | enum XML_Error err = XML_GetErrorCode (parser->expat_parser); | |
465 | error_string = XML_ErrorString (err); | |
466 | } | |
467 | else | |
468 | { | |
469 | gdb_assert (parser->error.reason < 0); | |
470 | throw_exception (parser->error); | |
471 | } | |
472 | ||
473 | if (parser->last_line != 0) | |
474 | warning (_("while parsing %s (at line %d): %s"), parser->name, | |
475 | parser->last_line, error_string); | |
476 | else | |
477 | warning (_("while parsing %s: %s"), parser->name, error_string); | |
478 | ||
479 | return -1; | |
fd79ecee DJ |
480 | } |
481 | ||
482 | /* Parse a field VALSTR that we expect to contain an integer value. | |
483 | The integer is returned in *VALP. The string is parsed with an | |
484 | equivalent to strtoul. | |
485 | ||
486 | Returns 0 for success, -1 for error. */ | |
487 | ||
488 | static int | |
489 | xml_parse_unsigned_integer (const char *valstr, ULONGEST *valp) | |
490 | { | |
491 | const char *endptr; | |
492 | ULONGEST result; | |
493 | ||
494 | if (*valstr == '\0') | |
495 | return -1; | |
496 | ||
497 | result = strtoulst (valstr, &endptr, 0); | |
498 | if (*endptr != '\0') | |
499 | return -1; | |
500 | ||
501 | *valp = result; | |
502 | return 0; | |
503 | } | |
504 | ||
e776119f DJ |
505 | /* Parse an integer string into a ULONGEST and return it, or call |
506 | gdb_xml_error if it could not be parsed. */ | |
fd79ecee DJ |
507 | |
508 | ULONGEST | |
e776119f | 509 | gdb_xml_parse_ulongest (struct gdb_xml_parser *parser, const char *value) |
fd79ecee DJ |
510 | { |
511 | ULONGEST result; | |
fd79ecee DJ |
512 | |
513 | if (xml_parse_unsigned_integer (value, &result) != 0) | |
e776119f DJ |
514 | gdb_xml_error (parser, _("Can't convert \"%s\" to an integer"), value); |
515 | ||
fd79ecee DJ |
516 | return result; |
517 | } | |
518 | ||
e776119f DJ |
519 | /* Parse an integer attribute into a ULONGEST. */ |
520 | ||
521 | void * | |
522 | gdb_xml_parse_attr_ulongest (struct gdb_xml_parser *parser, | |
523 | const struct gdb_xml_attribute *attribute, | |
524 | const char *value) | |
525 | { | |
526 | ULONGEST result; | |
527 | void *ret; | |
fd79ecee | 528 | |
e776119f DJ |
529 | if (xml_parse_unsigned_integer (value, &result) != 0) |
530 | gdb_xml_error (parser, _("Can't convert %s=\"%s\" to an integer"), | |
531 | attribute->name, value); | |
fd79ecee | 532 | |
e776119f DJ |
533 | ret = xmalloc (sizeof (result)); |
534 | memcpy (ret, &result, sizeof (result)); | |
535 | return ret; | |
536 | } | |
537 | ||
538 | /* Map NAME to VALUE. A struct gdb_xml_enum * should be saved as the | |
539 | value of handler_data when using gdb_xml_parse_attr_enum to parse a | |
540 | fixed list of possible strings. The list is terminated by an entry | |
541 | with NAME == NULL. */ | |
542 | ||
543 | void * | |
544 | gdb_xml_parse_attr_enum (struct gdb_xml_parser *parser, | |
545 | const struct gdb_xml_attribute *attribute, | |
546 | const char *value) | |
fd79ecee | 547 | { |
e776119f DJ |
548 | const struct gdb_xml_enum *enums = attribute->handler_data; |
549 | void *ret; | |
fd79ecee | 550 | |
e776119f DJ |
551 | for (enums = attribute->handler_data; enums->name != NULL; enums++) |
552 | if (strcmp (enums->name, value) == 0) | |
553 | break; | |
554 | ||
555 | if (enums->name == NULL) | |
556 | gdb_xml_error (parser, _("Unknown attribute value %s=\"%s\""), | |
557 | attribute->name, value); | |
558 | ||
559 | ret = xmalloc (sizeof (enums->value)); | |
560 | memcpy (ret, &enums->value, sizeof (enums->value)); | |
561 | return ret; | |
fd79ecee DJ |
562 | } |
563 | ||
e776119f | 564 | #endif /* HAVE_LIBEXPAT */ |
fd79ecee DJ |
565 | |
566 | static void | |
e776119f DJ |
567 | show_debug_xml (struct ui_file *file, int from_tty, |
568 | struct cmd_list_element *c, const char *value) | |
fd79ecee | 569 | { |
e776119f | 570 | fprintf_filtered (file, _("XML debugging is %s.\n"), value); |
fd79ecee DJ |
571 | } |
572 | ||
e776119f | 573 | void _initialize_xml_support (void); |
fd79ecee DJ |
574 | |
575 | void | |
e776119f | 576 | _initialize_xml_support (void) |
fd79ecee | 577 | { |
e776119f DJ |
578 | add_setshow_boolean_cmd ("xml", class_maintenance, &debug_xml, |
579 | _("Set XML parser debugging."), | |
580 | _("Show XML parser debugging."), | |
581 | _("When set, debugging messages for XML parsers " | |
582 | "are displayed."), | |
583 | NULL, show_debug_xml, | |
584 | &setdebuglist, &showdebuglist); | |
fd79ecee | 585 | } |