xref: /netbsd-src/common/lib/libprop/prop_object.c (revision 466a16a118933bd295a8a104f095714fadf9cf68)
1 /*	$NetBSD: prop_object.c,v 1.23 2008/11/30 00:17:07 haad Exp $	*/
2 
3 /*-
4  * Copyright (c) 2006, 2007 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Jason R. Thorpe.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 #include <prop/prop_object.h>
33 #include "prop_object_impl.h"
34 
35 #if !defined(_KERNEL) && !defined(_STANDALONE)
36 #include <sys/mman.h>
37 #include <sys/stat.h>
38 #include <errno.h>
39 #include <fcntl.h>
40 #include <limits.h>
41 #include <unistd.h>
42 #endif
43 
44 #ifdef _STANDALONE
45 void *
46 _prop_standalone_calloc(size_t size)
47 {
48 	void *rv;
49 
50 	rv = alloc(size);
51 	if (rv != NULL)
52 		memset(rv, 0, size);
53 
54 	return (rv);
55 }
56 
57 void *
58 _prop_standalone_realloc(void *v, size_t size)
59 {
60 	void *rv;
61 
62 	rv = alloc(size);
63 	if (rv != NULL) {
64 		memcpy(rv, v, size);	/* XXX */
65 		dealloc(v, 0);		/* XXX */
66 	}
67 
68 	return (rv);
69 }
70 #endif /* _STANDALONE */
71 
72 /*
73  * _prop_object_init --
74  *	Initialize an object.  Called when sub-classes create
75  *	an instance.
76  */
77 void
78 _prop_object_init(struct _prop_object *po, const struct _prop_object_type *pot)
79 {
80 
81 	po->po_type = pot;
82 	po->po_refcnt = 1;
83 }
84 
85 /*
86  * _prop_object_fini --
87  *	Finalize an object.  Called when sub-classes destroy
88  *	an instance.
89  */
90 /*ARGSUSED*/
91 void
92 _prop_object_fini(struct _prop_object *po _PROP_ARG_UNUSED)
93 {
94 	/* Nothing to do, currently. */
95 }
96 
97 /*
98  * _prop_object_externalize_start_tag --
99  *	Append an XML-style start tag to the externalize buffer.
100  */
101 bool
102 _prop_object_externalize_start_tag(
103     struct _prop_object_externalize_context *ctx, const char *tag)
104 {
105 	unsigned int i;
106 
107 	for (i = 0; i < ctx->poec_depth; i++) {
108 		if (_prop_object_externalize_append_char(ctx, '\t') == false)
109 			return (false);
110 	}
111 	if (_prop_object_externalize_append_char(ctx, '<') == false ||
112 	    _prop_object_externalize_append_cstring(ctx, tag) == false ||
113 	    _prop_object_externalize_append_char(ctx, '>') == false)
114 		return (false);
115 
116 	return (true);
117 }
118 
119 /*
120  * _prop_object_externalize_end_tag --
121  *	Append an XML-style end tag to the externalize buffer.
122  */
123 bool
124 _prop_object_externalize_end_tag(
125     struct _prop_object_externalize_context *ctx, const char *tag)
126 {
127 
128 	if (_prop_object_externalize_append_char(ctx, '<') == false ||
129 	    _prop_object_externalize_append_char(ctx, '/') == false ||
130 	    _prop_object_externalize_append_cstring(ctx, tag) == false ||
131 	    _prop_object_externalize_append_char(ctx, '>') == false ||
132 	    _prop_object_externalize_append_char(ctx, '\n') == false)
133 		return (false);
134 
135 	return (true);
136 }
137 
138 /*
139  * _prop_object_externalize_empty_tag --
140  *	Append an XML-style empty tag to the externalize buffer.
141  */
142 bool
143 _prop_object_externalize_empty_tag(
144     struct _prop_object_externalize_context *ctx, const char *tag)
145 {
146 	unsigned int i;
147 
148 	for (i = 0; i < ctx->poec_depth; i++) {
149 		if (_prop_object_externalize_append_char(ctx, '\t') == false)
150 			return (false);
151 	}
152 
153 	if (_prop_object_externalize_append_char(ctx, '<') == false ||
154 	    _prop_object_externalize_append_cstring(ctx, tag) == false ||
155 	    _prop_object_externalize_append_char(ctx, '/') == false ||
156 	    _prop_object_externalize_append_char(ctx, '>') == false ||
157 	    _prop_object_externalize_append_char(ctx, '\n') == false)
158 	    	return (false);
159 
160 	return (true);
161 }
162 
163 /*
164  * _prop_object_externalize_append_cstring --
165  *	Append a C string to the externalize buffer.
166  */
167 bool
168 _prop_object_externalize_append_cstring(
169     struct _prop_object_externalize_context *ctx, const char *cp)
170 {
171 
172 	while (*cp != '\0') {
173 		if (_prop_object_externalize_append_char(ctx,
174 						(unsigned char) *cp) == false)
175 			return (false);
176 		cp++;
177 	}
178 
179 	return (true);
180 }
181 
182 /*
183  * _prop_object_externalize_append_encoded_cstring --
184  *	Append an encoded C string to the externalize buffer.
185  */
186 bool
187 _prop_object_externalize_append_encoded_cstring(
188     struct _prop_object_externalize_context *ctx, const char *cp)
189 {
190 
191 	while (*cp != '\0') {
192 		switch (*cp) {
193 		case '<':
194 			if (_prop_object_externalize_append_cstring(ctx,
195 					"&lt;") == false)
196 				return (false);
197 			break;
198 		case '>':
199 			if (_prop_object_externalize_append_cstring(ctx,
200 					"&gt;") == false)
201 				return (false);
202 			break;
203 		case '&':
204 			if (_prop_object_externalize_append_cstring(ctx,
205 					"&amp;") == false)
206 				return (false);
207 			break;
208 		default:
209 			if (_prop_object_externalize_append_char(ctx,
210 					(unsigned char) *cp) == false)
211 				return (false);
212 			break;
213 		}
214 		cp++;
215 	}
216 
217 	return (true);
218 }
219 
220 #define	BUF_EXPAND		256
221 
222 /*
223  * _prop_object_externalize_append_char --
224  *	Append a single character to the externalize buffer.
225  */
226 bool
227 _prop_object_externalize_append_char(
228     struct _prop_object_externalize_context *ctx, unsigned char c)
229 {
230 
231 	_PROP_ASSERT(ctx->poec_capacity != 0);
232 	_PROP_ASSERT(ctx->poec_buf != NULL);
233 	_PROP_ASSERT(ctx->poec_len <= ctx->poec_capacity);
234 
235 	if (ctx->poec_len == ctx->poec_capacity) {
236 		char *cp = _PROP_REALLOC(ctx->poec_buf,
237 					 ctx->poec_capacity + BUF_EXPAND,
238 					 M_TEMP);
239 		if (cp == NULL)
240 			return (false);
241 		ctx->poec_capacity = ctx->poec_capacity + BUF_EXPAND;
242 		ctx->poec_buf = cp;
243 	}
244 
245 	ctx->poec_buf[ctx->poec_len++] = c;
246 
247 	return (true);
248 }
249 
250 /*
251  * _prop_object_externalize_header --
252  *	Append the standard XML header to the externalize buffer.
253  */
254 bool
255 _prop_object_externalize_header(struct _prop_object_externalize_context *ctx)
256 {
257 	static const char _plist_xml_header[] =
258 "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
259 "<!DOCTYPE plist PUBLIC \"-//Apple Computer//DTD PLIST 1.0//EN\" \"http://www.apple.com/DTDs/PropertyList-1.0.dtd\">\n";
260 
261 	if (_prop_object_externalize_append_cstring(ctx,
262 						 _plist_xml_header) == false ||
263 	    _prop_object_externalize_start_tag(ctx,
264 				       "plist version=\"1.0\"") == false ||
265 	    _prop_object_externalize_append_char(ctx, '\n') == false)
266 		return (false);
267 
268 	return (true);
269 }
270 
271 /*
272  * _prop_object_externalize_footer --
273  *	Append the standard XML footer to the externalize buffer.  This
274  *	also NUL-terminates the buffer.
275  */
276 bool
277 _prop_object_externalize_footer(struct _prop_object_externalize_context *ctx)
278 {
279 
280 	if (_prop_object_externalize_end_tag(ctx, "plist") == false ||
281 	    _prop_object_externalize_append_char(ctx, '\0') == false)
282 		return (false);
283 
284 	return (true);
285 }
286 
287 /*
288  * _prop_object_externalize_context_alloc --
289  *	Allocate an externalize context.
290  */
291 struct _prop_object_externalize_context *
292 _prop_object_externalize_context_alloc(void)
293 {
294 	struct _prop_object_externalize_context *ctx;
295 
296 	ctx = _PROP_MALLOC(sizeof(*ctx), M_TEMP);
297 	if (ctx != NULL) {
298 		ctx->poec_buf = _PROP_MALLOC(BUF_EXPAND, M_TEMP);
299 		if (ctx->poec_buf == NULL) {
300 			_PROP_FREE(ctx, M_TEMP);
301 			return (NULL);
302 		}
303 		ctx->poec_len = 0;
304 		ctx->poec_capacity = BUF_EXPAND;
305 		ctx->poec_depth = 0;
306 	}
307 	return (ctx);
308 }
309 
310 /*
311  * _prop_object_externalize_context_free --
312  *	Free an externalize context.
313  */
314 void
315 _prop_object_externalize_context_free(
316 		struct _prop_object_externalize_context *ctx)
317 {
318 
319 	/* Buffer is always freed by the caller. */
320 	_PROP_FREE(ctx, M_TEMP);
321 }
322 
323 /*
324  * _prop_object_internalize_skip_comment --
325  *	Skip the body and end tag of a comment.
326  */
327 static bool
328 _prop_object_internalize_skip_comment(
329 				struct _prop_object_internalize_context *ctx)
330 {
331 	const char *cp = ctx->poic_cp;
332 
333 	while (!_PROP_EOF(*cp)) {
334 		if (cp[0] == '-' &&
335 		    cp[1] == '-' &&
336 		    cp[2] == '>') {
337 			ctx->poic_cp = cp + 3;
338 			return (true);
339 		}
340 		cp++;
341 	}
342 
343 	return (false);		/* ran out of buffer */
344 }
345 
346 /*
347  * _prop_object_internalize_find_tag --
348  *	Find the next tag in an XML stream.  Optionally compare the found
349  *	tag to an expected tag name.  State of the context is undefined
350  *	if this routine returns false.  Upon success, the context points
351  *	to the first octet after the tag.
352  */
353 bool
354 _prop_object_internalize_find_tag(struct _prop_object_internalize_context *ctx,
355 		      const char *tag, _prop_tag_type_t type)
356 {
357 	const char *cp;
358 	size_t taglen;
359 
360 	if (tag != NULL)
361 		taglen = strlen(tag);
362 	else
363 		taglen = 0;
364 
365  start_over:
366 	cp = ctx->poic_cp;
367 
368 	/*
369 	 * Find the start of the tag.
370 	 */
371 	while (_PROP_ISSPACE(*cp))
372 		cp++;
373 	if (_PROP_EOF(*cp))
374 		return (false);
375 
376 	if (*cp != '<')
377 		return (false);
378 
379 	ctx->poic_tag_start = cp++;
380 	if (_PROP_EOF(*cp))
381 		return (false);
382 
383 	if (*cp == '!') {
384 		if (cp[1] != '-' || cp[2] != '-')
385 			return (false);
386 		/*
387 		 * Comment block -- only allowed if we are allowed to
388 		 * return a start tag.
389 		 */
390 		if (type == _PROP_TAG_TYPE_END)
391 			return (false);
392 		ctx->poic_cp = cp + 3;
393 		if (_prop_object_internalize_skip_comment(ctx) == false)
394 			return (false);
395 		goto start_over;
396 	}
397 
398 	if (*cp == '/') {
399 		if (type != _PROP_TAG_TYPE_END &&
400 		    type != _PROP_TAG_TYPE_EITHER)
401 			return (false);
402 		cp++;
403 		if (_PROP_EOF(*cp))
404 			return (false);
405 		ctx->poic_tag_type = _PROP_TAG_TYPE_END;
406 	} else {
407 		if (type != _PROP_TAG_TYPE_START &&
408 		    type != _PROP_TAG_TYPE_EITHER)
409 			return (false);
410 		ctx->poic_tag_type = _PROP_TAG_TYPE_START;
411 	}
412 
413 	ctx->poic_tagname = cp;
414 
415 	while (!_PROP_ISSPACE(*cp) && *cp != '/' && *cp != '>')
416 		cp++;
417 	if (_PROP_EOF(*cp))
418 		return (false);
419 
420 	ctx->poic_tagname_len = cp - ctx->poic_tagname;
421 
422 	/* Make sure this is the tag we're looking for. */
423 	if (tag != NULL &&
424 	    (taglen != ctx->poic_tagname_len ||
425 	     memcmp(tag, ctx->poic_tagname, taglen) != 0))
426 		return (false);
427 
428 	/* Check for empty tag. */
429 	if (*cp == '/') {
430 		if (ctx->poic_tag_type != _PROP_TAG_TYPE_START)
431 			return(false);		/* only valid on start tags */
432 		ctx->poic_is_empty_element = true;
433 		cp++;
434 		if (_PROP_EOF(*cp) || *cp != '>')
435 			return (false);
436 	} else
437 		ctx->poic_is_empty_element = false;
438 
439 	/* Easy case of no arguments. */
440 	if (*cp == '>') {
441 		ctx->poic_tagattr = NULL;
442 		ctx->poic_tagattr_len = 0;
443 		ctx->poic_tagattrval = NULL;
444 		ctx->poic_tagattrval_len = 0;
445 		ctx->poic_cp = cp + 1;
446 		return (true);
447 	}
448 
449 	_PROP_ASSERT(!_PROP_EOF(*cp));
450 	cp++;
451 	if (_PROP_EOF(*cp))
452 		return (false);
453 
454 	while (_PROP_ISSPACE(*cp))
455 		cp++;
456 	if (_PROP_EOF(*cp))
457 		return (false);
458 
459 	ctx->poic_tagattr = cp;
460 
461 	while (!_PROP_ISSPACE(*cp) && *cp != '=')
462 		cp++;
463 	if (_PROP_EOF(*cp))
464 		return (false);
465 
466 	ctx->poic_tagattr_len = cp - ctx->poic_tagattr;
467 
468 	cp++;
469 	if (*cp != '\"')
470 		return (false);
471 	cp++;
472 	if (_PROP_EOF(*cp))
473 		return (false);
474 
475 	ctx->poic_tagattrval = cp;
476 	while (*cp != '\"')
477 		cp++;
478 	if (_PROP_EOF(*cp))
479 		return (false);
480 	ctx->poic_tagattrval_len = cp - ctx->poic_tagattrval;
481 
482 	cp++;
483 	if (*cp != '>')
484 		return (false);
485 
486 	ctx->poic_cp = cp + 1;
487 	return (true);
488 }
489 
490 /*
491  * _prop_object_internalize_decode_string --
492  *	Decode an encoded string.
493  */
494 bool
495 _prop_object_internalize_decode_string(
496 				struct _prop_object_internalize_context *ctx,
497 				char *target, size_t targsize, size_t *sizep,
498 				const char **cpp)
499 {
500 	const char *src;
501 	size_t tarindex;
502 	char c;
503 
504 	tarindex = 0;
505 	src = ctx->poic_cp;
506 
507 	for (;;) {
508 		if (_PROP_EOF(*src))
509 			return (false);
510 		if (*src == '<') {
511 			break;
512 		}
513 
514 		if ((c = *src) == '&') {
515 			if (src[1] == 'a' &&
516 			    src[2] == 'm' &&
517 			    src[3] == 'p' &&
518 			    src[4] == ';') {
519 			    	c = '&';
520 				src += 5;
521 			} else if (src[1] == 'l' &&
522 				   src[2] == 't' &&
523 				   src[3] == ';') {
524 				c = '<';
525 				src += 4;
526 			} else if (src[1] == 'g' &&
527 				   src[2] == 't' &&
528 				   src[3] == ';') {
529 				c = '>';
530 				src += 4;
531 			} else if (src[1] == 'a' &&
532 				   src[2] == 'p' &&
533 				   src[3] == 'o' &&
534 				   src[4] == 's' &&
535 				   src[5] == ';') {
536 				c = '\'';
537 				src += 6;
538 			} else if (src[1] == 'q' &&
539 				   src[2] == 'u' &&
540 				   src[3] == 'o' &&
541 				   src[4] == 't' &&
542 				   src[5] == ';') {
543 				c = '\"';
544 				src += 6;
545 			} else
546 				return (false);
547 		} else
548 			src++;
549 		if (target) {
550 			if (tarindex >= targsize)
551 				return (false);
552 			target[tarindex] = c;
553 		}
554 		tarindex++;
555 	}
556 
557 	_PROP_ASSERT(*src == '<');
558 	if (sizep != NULL)
559 		*sizep = tarindex;
560 	if (cpp != NULL)
561 		*cpp = src;
562 
563 	return (true);
564 }
565 
566 /*
567  * _prop_object_internalize_match --
568  *	Returns true if the two character streams match.
569  */
570 bool
571 _prop_object_internalize_match(const char *str1, size_t len1,
572 			       const char *str2, size_t len2)
573 {
574 
575 	return (len1 == len2 && memcmp(str1, str2, len1) == 0);
576 }
577 
578 #define	INTERNALIZER(t, f)			\
579 {	t,	sizeof(t) - 1,		f	}
580 
581 static const struct _prop_object_internalizer {
582 	const char			*poi_tag;
583 	size_t				poi_taglen;
584 	prop_object_internalizer_t	poi_intern;
585 } _prop_object_internalizer_table[] = {
586 	INTERNALIZER("array", _prop_array_internalize),
587 
588 	INTERNALIZER("true", _prop_bool_internalize),
589 	INTERNALIZER("false", _prop_bool_internalize),
590 
591 	INTERNALIZER("data", _prop_data_internalize),
592 
593 	INTERNALIZER("dict", _prop_dictionary_internalize),
594 
595 	INTERNALIZER("integer", _prop_number_internalize),
596 
597 	INTERNALIZER("string", _prop_string_internalize),
598 
599 	{ 0, 0, NULL }
600 };
601 
602 #undef INTERNALIZER
603 
604 /*
605  * _prop_object_internalize_by_tag --
606  *	Determine the object type from the tag in the context and
607  *	internalize it.
608  */
609 prop_object_t
610 _prop_object_internalize_by_tag(struct _prop_object_internalize_context *ctx)
611 {
612 	const struct _prop_object_internalizer *poi;
613 	prop_object_t obj, parent_obj;
614 	void *data, *iter;
615 	prop_object_internalizer_continue_t iter_func;
616 	struct _prop_stack stack;
617 
618 	_prop_stack_init(&stack);
619 
620 match_start:
621 	for (poi = _prop_object_internalizer_table;
622 	     poi->poi_tag != NULL; poi++) {
623 		if (_prop_object_internalize_match(ctx->poic_tagname,
624 						   ctx->poic_tagname_len,
625 						   poi->poi_tag,
626 						   poi->poi_taglen))
627 			break;
628 	}
629 	if (poi == NULL) {
630 		while (_prop_stack_pop(&stack, &obj, &iter, &data, NULL)) {
631 			iter_func = (prop_object_internalizer_continue_t)iter;
632 			(*iter_func)(&stack, &obj, ctx, data, NULL);
633 		}
634 
635 		return (NULL);
636 	}
637 
638 	obj = NULL;
639 	if (!(*poi->poi_intern)(&stack, &obj, ctx))
640 		goto match_start;
641 
642 	parent_obj = obj;
643 	while (_prop_stack_pop(&stack, &parent_obj, &iter, &data, NULL)) {
644 		iter_func = (prop_object_internalizer_continue_t)iter;
645 		if (!(*iter_func)(&stack, &parent_obj, ctx, data, obj))
646 			goto match_start;
647 		obj = parent_obj;
648 	}
649 
650 	return (parent_obj);
651 }
652 
653 prop_object_t
654 _prop_generic_internalize(const char *xml, const char *master_tag)
655 {
656 	prop_object_t obj = NULL;
657 	struct _prop_object_internalize_context *ctx;
658 
659 	ctx = _prop_object_internalize_context_alloc(xml);
660 	if (ctx == NULL)
661 		return (NULL);
662 
663 	/* We start with a <plist> tag. */
664 	if (_prop_object_internalize_find_tag(ctx, "plist",
665 					      _PROP_TAG_TYPE_START) == false)
666 		goto out;
667 
668 	/* Plist elements cannot be empty. */
669 	if (ctx->poic_is_empty_element)
670 		goto out;
671 
672 	/*
673 	 * We don't understand any plist attributes, but Apple XML
674 	 * property lists often have a "version" attribute.  If we
675 	 * see that one, we simply ignore it.
676 	 */
677 	if (ctx->poic_tagattr != NULL &&
678 	    !_PROP_TAGATTR_MATCH(ctx, "version"))
679 		goto out;
680 
681 	/* Next we expect to see opening master_tag. */
682 	if (_prop_object_internalize_find_tag(ctx, master_tag,
683 					      _PROP_TAG_TYPE_START) == false)
684 		goto out;
685 
686 	obj = _prop_object_internalize_by_tag(ctx);
687 	if (obj == NULL)
688 		goto out;
689 
690 	/*
691 	 * We've advanced past the closing master_tag.
692 	 * Now we want </plist>.
693 	 */
694 	if (_prop_object_internalize_find_tag(ctx, "plist",
695 					      _PROP_TAG_TYPE_END) == false) {
696 		prop_object_release(obj);
697 		obj = NULL;
698 	}
699 
700  out:
701  	_prop_object_internalize_context_free(ctx);
702 	return (obj);
703 }
704 
705 /*
706  * _prop_object_internalize_context_alloc --
707  *	Allocate an internalize context.
708  */
709 struct _prop_object_internalize_context *
710 _prop_object_internalize_context_alloc(const char *xml)
711 {
712 	struct _prop_object_internalize_context *ctx;
713 
714 	ctx = _PROP_MALLOC(sizeof(struct _prop_object_internalize_context),
715 			   M_TEMP);
716 	if (ctx == NULL)
717 		return (NULL);
718 
719 	ctx->poic_xml = ctx->poic_cp = xml;
720 
721 	/*
722 	 * Skip any whitespace and XML preamble stuff that we don't
723 	 * know about / care about.
724 	 */
725 	for (;;) {
726 		while (_PROP_ISSPACE(*xml))
727 			xml++;
728 		if (_PROP_EOF(*xml) || *xml != '<')
729 			goto bad;
730 
731 #define	MATCH(str)	(memcmp(&xml[1], str, sizeof(str) - 1) == 0)
732 
733 		/*
734 		 * Skip over the XML preamble that Apple XML property
735 		 * lists usually include at the top of the file.
736 		 */
737 		if (MATCH("?xml ") ||
738 		    MATCH("!DOCTYPE plist")) {
739 			while (*xml != '>' && !_PROP_EOF(*xml))
740 				xml++;
741 			if (_PROP_EOF(*xml))
742 				goto bad;
743 			xml++;	/* advance past the '>' */
744 			continue;
745 		}
746 
747 		if (MATCH("<!--")) {
748 			ctx->poic_cp = xml + 4;
749 			if (_prop_object_internalize_skip_comment(ctx) == false)
750 				goto bad;
751 			xml = ctx->poic_cp;
752 			continue;
753 		}
754 
755 #undef MATCH
756 
757 		/*
758 		 * We don't think we should skip it, so let's hope we can
759 		 * parse it.
760 		 */
761 		break;
762 	}
763 
764 	ctx->poic_cp = xml;
765 	return (ctx);
766  bad:
767 	_PROP_FREE(ctx, M_TEMP);
768 	return (NULL);
769 }
770 
771 /*
772  * _prop_object_internalize_context_free --
773  *	Free an internalize context.
774  */
775 void
776 _prop_object_internalize_context_free(
777 		struct _prop_object_internalize_context *ctx)
778 {
779 
780 	_PROP_FREE(ctx, M_TEMP);
781 }
782 
783 #if !defined(_KERNEL) && !defined(_STANDALONE)
784 /*
785  * _prop_object_externalize_file_dirname --
786  *	dirname(3), basically.  We have to roll our own because the
787  *	system dirname(3) isn't reentrant.
788  */
789 static void
790 _prop_object_externalize_file_dirname(const char *path, char *result)
791 {
792 	const char *lastp;
793 	size_t len;
794 
795 	/*
796 	 * If `path' is a NULL pointer or points to an empty string,
797 	 * return ".".
798 	 */
799 	if (path == NULL || *path == '\0')
800 		goto singledot;
801 
802 	/* String trailing slashes, if any. */
803 	lastp = path + strlen(path) - 1;
804 	while (lastp != path && *lastp == '/')
805 		lastp--;
806 
807 	/* Terminate path at the last occurrence of '/'. */
808 	do {
809 		if (*lastp == '/') {
810 			/* Strip trailing slashes, if any. */
811 			while (lastp != path && *lastp == '/')
812 				lastp--;
813 
814 			/* ...and copy the result into the result buffer. */
815 			len = (lastp - path) + 1 /* last char */;
816 			if (len > (PATH_MAX - 1))
817 				len = PATH_MAX - 1;
818 
819 			memcpy(result, path, len);
820 			result[len] = '\0';
821 			return;
822 		}
823 	} while (--lastp >= path);
824 
825  	/* No /'s found, return ".". */
826  singledot:
827 	strcpy(result, ".");
828 }
829 
830 /*
831  * _prop_object_externalize_write_file --
832  *	Write an externalized dictionary to the specified file.
833  *	The file is written atomically from the caller's perspective,
834  *	and the mode set to 0666 modified by the caller's umask.
835  */
836 bool
837 _prop_object_externalize_write_file(const char *fname, const char *xml,
838     size_t len)
839 {
840 	char tname[PATH_MAX];
841 	int fd;
842 	int save_errno;
843 	mode_t myumask;
844 
845 	if (len > SSIZE_MAX) {
846 		errno = EFBIG;
847 		return (false);
848 	}
849 
850 	/*
851 	 * Get the directory name where the file is to be written
852 	 * and create the temporary file.
853 	 */
854 	_prop_object_externalize_file_dirname(fname, tname);
855 	if (strlcat(tname, "/.plistXXXXXX", sizeof(tname)) >= sizeof(tname)) {
856 		errno = ENAMETOOLONG;
857 		return (false);
858 	}
859 	if ((fd = mkstemp(tname)) == -1)
860 		return (false);
861 
862 	if (write(fd, xml, len) != (ssize_t)len)
863 		goto bad;
864 
865 	if (fsync(fd) == -1)
866 		goto bad;
867 
868 	myumask = umask(0);
869 	(void)umask(myumask);
870 	if (fchmod(fd, 0666 & ~myumask) == -1)
871 		goto bad;
872 
873 	(void) close(fd);
874 	fd = -1;
875 
876 	if (rename(tname, fname) == -1)
877 		goto bad;
878 
879 	return (true);
880 
881  bad:
882 	save_errno = errno;
883 	if (fd != -1)
884 		(void) close(fd);
885 	(void) unlink(tname);
886 	errno = save_errno;
887 	return (false);
888 }
889 
890 /*
891  * _prop_object_internalize_map_file --
892  *	Map a file for the purpose of internalizing it.
893  */
894 struct _prop_object_internalize_mapped_file *
895 _prop_object_internalize_map_file(const char *fname)
896 {
897 	struct stat sb;
898 	struct _prop_object_internalize_mapped_file *mf;
899 	size_t pgsize = (size_t)sysconf(_SC_PAGESIZE);
900 	size_t pgmask = pgsize - 1;
901 	bool need_guard = false;
902 	int fd;
903 
904 	mf = _PROP_MALLOC(sizeof(*mf), M_TEMP);
905 	if (mf == NULL)
906 		return (NULL);
907 
908 	fd = open(fname, O_RDONLY, 0400);
909 	if (fd == -1) {
910 		_PROP_FREE(mf, M_TEMP);
911 		return (NULL);
912 	}
913 
914 	if (fstat(fd, &sb) == -1) {
915 		(void) close(fd);
916 		_PROP_FREE(mf, M_TEMP);
917 		return (NULL);
918 	}
919 	mf->poimf_mapsize = ((size_t)sb.st_size + pgmask) & ~pgmask;
920 	if (mf->poimf_mapsize < sb.st_size) {
921 		(void) close(fd);
922 		_PROP_FREE(mf, M_TEMP);
923 		return (NULL);
924 	}
925 
926 	/*
927 	 * If the file length is an integral number of pages, then we
928 	 * need to map a guard page at the end in order to provide the
929 	 * necessary NUL-termination of the buffer.
930 	 */
931 	if ((sb.st_size & pgmask) == 0)
932 		need_guard = true;
933 
934 	mf->poimf_xml = mmap(NULL, need_guard ? mf->poimf_mapsize + pgsize
935 			    		      : mf->poimf_mapsize,
936 			    PROT_READ, MAP_FILE|MAP_SHARED, fd, (off_t)0);
937 	(void) close(fd);
938 	if (mf->poimf_xml == MAP_FAILED) {
939 		_PROP_FREE(mf, M_TEMP);
940 		return (NULL);
941 	}
942 	(void) madvise(mf->poimf_xml, mf->poimf_mapsize, MADV_SEQUENTIAL);
943 
944 	if (need_guard) {
945 		if (mmap(mf->poimf_xml + mf->poimf_mapsize,
946 			 pgsize, PROT_READ,
947 			 MAP_ANON|MAP_PRIVATE|MAP_FIXED, -1,
948 			 (off_t)0) == MAP_FAILED) {
949 			(void) munmap(mf->poimf_xml, mf->poimf_mapsize);
950 			_PROP_FREE(mf, M_TEMP);
951 			return (NULL);
952 		}
953 		mf->poimf_mapsize += pgsize;
954 	}
955 
956 	return (mf);
957 }
958 
959 /*
960  * _prop_object_internalize_unmap_file --
961  *	Unmap a file previously mapped for internalizing.
962  */
963 void
964 _prop_object_internalize_unmap_file(
965     struct _prop_object_internalize_mapped_file *mf)
966 {
967 
968 	(void) madvise(mf->poimf_xml, mf->poimf_mapsize, MADV_DONTNEED);
969 	(void) munmap(mf->poimf_xml, mf->poimf_mapsize);
970 	_PROP_FREE(mf, M_TEMP);
971 }
972 #endif /* !_KERNEL && !_STANDALONE */
973 
974 /*
975  * Retain / release serialization --
976  *
977  * Eventually we would like to use atomic operations.  But until we have
978  * an MI API for them that is common to userland and the kernel, we will
979  * use a lock instead.
980  *
981  * We use a single global mutex for all serialization.  In the kernel, because
982  * we are still under a biglock, this will basically never contend (properties
983  * cannot be manipulated at interrupt level).  In userland, this will cost
984  * nothing for single-threaded programs.  For multi-threaded programs, there
985  * could be contention, but it probably won't cost that much unless the program
986  * makes heavy use of property lists.
987  */
988 _PROP_MUTEX_DECL_STATIC(_prop_refcnt_mutex)
989 #define	_PROP_REFCNT_LOCK()	_PROP_MUTEX_LOCK(_prop_refcnt_mutex)
990 #define	_PROP_REFCNT_UNLOCK()	_PROP_MUTEX_UNLOCK(_prop_refcnt_mutex)
991 
992 /*
993  * prop_object_retain --
994  *	Increment the reference count on an object.
995  */
996 void
997 prop_object_retain(prop_object_t obj)
998 {
999 	struct _prop_object *po = obj;
1000 	uint32_t ocnt;
1001 
1002 	_PROP_REFCNT_LOCK();
1003 	ocnt = po->po_refcnt++;
1004 	_PROP_REFCNT_UNLOCK();
1005 
1006 	_PROP_ASSERT(ocnt != 0xffffffffU);
1007 }
1008 
1009 /*
1010  * prop_object_release_emergency
1011  *	A direct free with prop_object_release failed.
1012  *	Walk down the tree until a leaf is found and
1013  *	free that. Do not recurse to avoid stack overflows.
1014  *
1015  *	This is a slow edge condition, but necessary to
1016  *	guarantee that an object can always be freed.
1017  */
1018 static void
1019 prop_object_release_emergency(prop_object_t obj)
1020 {
1021 	struct _prop_object *po;
1022 	void (*unlock)(void);
1023 	prop_object_t parent = NULL;
1024 	uint32_t ocnt;
1025 
1026 	for (;;) {
1027 		po = obj;
1028 		_PROP_ASSERT(obj);
1029 
1030 		if (po->po_type->pot_lock != NULL)
1031 		po->po_type->pot_lock();
1032 
1033 		/* Save pointerto unlock function */
1034 		unlock = po->po_type->pot_unlock;
1035 
1036 		_PROP_REFCNT_LOCK();
1037     		ocnt = po->po_refcnt--;
1038 		_PROP_REFCNT_UNLOCK();
1039 
1040 		_PROP_ASSERT(ocnt != 0);
1041 		if (ocnt != 1) {
1042 			if (unlock != NULL)
1043 				unlock();
1044 			break;
1045 		}
1046 
1047 		_PROP_ASSERT(po->po_type);
1048 		if ((po->po_type->pot_free)(NULL, &obj) ==
1049 		    _PROP_OBJECT_FREE_DONE) {
1050 			if (unlock != NULL)
1051 				unlock();
1052 			break;
1053 		}
1054 
1055 		if (unlock != NULL)
1056 			unlock();
1057 
1058 		parent = po;
1059 		_PROP_REFCNT_LOCK();
1060 		++po->po_refcnt;
1061 		_PROP_REFCNT_UNLOCK();
1062 	}
1063 	_PROP_ASSERT(parent);
1064 	/* One object was just freed. */
1065 	po = parent;
1066 	(*po->po_type->pot_emergency_free)(parent);
1067 }
1068 
1069 /*
1070  * prop_object_release --
1071  *	Decrement the reference count on an object.
1072  *
1073  *	Free the object if we are releasing the final
1074  *	reference.
1075  */
1076 void
1077 prop_object_release(prop_object_t obj)
1078 {
1079 	struct _prop_object *po;
1080 	struct _prop_stack stack;
1081 	void (*unlock)(void);
1082 	int ret;
1083 	uint32_t ocnt;
1084 
1085 	_prop_stack_init(&stack);
1086 
1087 	do {
1088 		do {
1089 			po = obj;
1090 			_PROP_ASSERT(obj);
1091 
1092 			if (po->po_type->pot_lock != NULL)
1093 				po->po_type->pot_lock();
1094 
1095 			/* Save pointer to object unlock function */
1096 			unlock = po->po_type->pot_unlock;
1097 
1098 			_PROP_REFCNT_LOCK();
1099 			ocnt = po->po_refcnt--;
1100 			_PROP_REFCNT_UNLOCK();
1101 
1102 			_PROP_ASSERT(ocnt != 0);
1103 			if (ocnt != 1) {
1104 				ret = 0;
1105 				if (unlock != NULL)
1106 					unlock();
1107 				break;
1108 			}
1109 
1110 			ret = (po->po_type->pot_free)(&stack, &obj);
1111 
1112 			if (unlock != NULL)
1113 				unlock();
1114 
1115 			if (ret == _PROP_OBJECT_FREE_DONE)
1116 				break;
1117 
1118 			_PROP_REFCNT_LOCK();
1119 			++po->po_refcnt;
1120 			_PROP_REFCNT_UNLOCK();
1121 		} while (ret == _PROP_OBJECT_FREE_RECURSE);
1122 		if (ret == _PROP_OBJECT_FREE_FAILED)
1123 			prop_object_release_emergency(obj);
1124 	} while (_prop_stack_pop(&stack, &obj, NULL, NULL, NULL));
1125 }
1126 
1127 /*
1128  * prop_object_type --
1129  *	Return the type of an object.
1130  */
1131 prop_type_t
1132 prop_object_type(prop_object_t obj)
1133 {
1134 	struct _prop_object *po = obj;
1135 
1136 	if (obj == NULL)
1137 		return (PROP_TYPE_UNKNOWN);
1138 
1139 	return (po->po_type->pot_type);
1140 }
1141 
1142 /*
1143  * prop_object_equals --
1144  *	Returns true if thw two objects are equivalent.
1145  */
1146 bool
1147 prop_object_equals(prop_object_t obj1, prop_object_t obj2)
1148 {
1149 	return (prop_object_equals_with_error(obj1, obj2, NULL));
1150 }
1151 
1152 bool
1153 prop_object_equals_with_error(prop_object_t obj1, prop_object_t obj2,
1154     bool *error_flag)
1155 {
1156 	struct _prop_object *po1;
1157 	struct _prop_object *po2;
1158 	void *stored_pointer1, *stored_pointer2;
1159 	prop_object_t next_obj1, next_obj2;
1160 	struct _prop_stack stack;
1161 	_prop_object_equals_rv_t ret;
1162 
1163 	_prop_stack_init(&stack);
1164 	if (error_flag)
1165 		*error_flag = false;
1166 
1167  start_subtree:
1168 	stored_pointer1 = NULL;
1169 	stored_pointer2 = NULL;
1170 	po1 = obj1;
1171 	po2 = obj2;
1172 
1173 	if (po1->po_type != po2->po_type)
1174 		return (false);
1175 
1176  continue_subtree:
1177 	ret = (*po1->po_type->pot_equals)(obj1, obj2,
1178 					  &stored_pointer1, &stored_pointer2,
1179 					  &next_obj1, &next_obj2);
1180 	if (ret == _PROP_OBJECT_EQUALS_FALSE)
1181 		goto finish;
1182 	if (ret == _PROP_OBJECT_EQUALS_TRUE) {
1183 		if (!_prop_stack_pop(&stack, &obj1, &obj2,
1184 				     &stored_pointer1, &stored_pointer2))
1185 			return true;
1186 		goto continue_subtree;
1187 	}
1188 	_PROP_ASSERT(ret == _PROP_OBJECT_EQUALS_RECURSE);
1189 
1190 	if (!_prop_stack_push(&stack, obj1, obj2,
1191 			      stored_pointer1, stored_pointer2)) {
1192 		if (error_flag)
1193 			*error_flag = true;
1194 		goto finish;
1195 	}
1196 	obj1 = next_obj1;
1197 	obj2 = next_obj2;
1198 	goto start_subtree;
1199 
1200 finish:
1201 	while (_prop_stack_pop(&stack, &obj1, &obj2, NULL, NULL)) {
1202 		po1 = obj1;
1203 		(*po1->po_type->pot_equals_finish)(obj1, obj2);
1204 	}
1205 	return (false);
1206 }
1207 
1208 /*
1209  * prop_object_iterator_next --
1210  *	Return the next item during an iteration.
1211  */
1212 prop_object_t
1213 prop_object_iterator_next(prop_object_iterator_t pi)
1214 {
1215 
1216 	return ((*pi->pi_next_object)(pi));
1217 }
1218 
1219 /*
1220  * prop_object_iterator_reset --
1221  *	Reset the iterator to the first object so as to restart
1222  *	iteration.
1223  */
1224 void
1225 prop_object_iterator_reset(prop_object_iterator_t pi)
1226 {
1227 
1228 	(*pi->pi_reset)(pi);
1229 }
1230 
1231 /*
1232  * prop_object_iterator_release --
1233  *	Release the object iterator.
1234  */
1235 void
1236 prop_object_iterator_release(prop_object_iterator_t pi)
1237 {
1238 
1239 	prop_object_release(pi->pi_obj);
1240 	_PROP_FREE(pi, M_TEMP);
1241 }
1242