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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Extra Boot Config
4 * Masami Hiramatsu <mhiramat@kernel.org>
5 */
6
7#define pr_fmt(fmt) "bootconfig: " fmt
8
9#include <linux/bootconfig.h>
10#include <linux/bug.h>
11#include <linux/ctype.h>
12#include <linux/errno.h>
13#include <linux/kernel.h>
14#include <linux/memblock.h>
15#include <linux/printk.h>
16#include <linux/string.h>
17
18/*
19 * Extra Boot Config (XBC) is given as tree-structured ascii text of
20 * key-value pairs on memory.
21 * xbc_parse() parses the text to build a simple tree. Each tree node is
22 * simply a key word or a value. A key node may have a next key node or/and
23 * a child node (both key and value). A value node may have a next value
24 * node (for array).
25 */
26
27static struct xbc_node *xbc_nodes __initdata;
28static int xbc_node_num __initdata;
29static char *xbc_data __initdata;
30static size_t xbc_data_size __initdata;
31static struct xbc_node *last_parent __initdata;
32static const char *xbc_err_msg __initdata;
33static int xbc_err_pos __initdata;
34static int open_brace[XBC_DEPTH_MAX] __initdata;
35static int brace_index __initdata;
36
37static int __init xbc_parse_error(const char *msg, const char *p)
38{
39 xbc_err_msg = msg;
40 xbc_err_pos = (int)(p - xbc_data);
41
42 return -EINVAL;
43}
44
45/**
46 * xbc_root_node() - Get the root node of extended boot config
47 *
48 * Return the address of root node of extended boot config. If the
49 * extended boot config is not initiized, return NULL.
50 */
51struct xbc_node * __init xbc_root_node(void)
52{
53 if (unlikely(!xbc_data))
54 return NULL;
55
56 return xbc_nodes;
57}
58
59/**
60 * xbc_node_index() - Get the index of XBC node
61 * @node: A target node of getting index.
62 *
63 * Return the index number of @node in XBC node list.
64 */
65int __init xbc_node_index(struct xbc_node *node)
66{
67 return node - &xbc_nodes[0];
68}
69
70/**
71 * xbc_node_get_parent() - Get the parent XBC node
72 * @node: An XBC node.
73 *
74 * Return the parent node of @node. If the node is top node of the tree,
75 * return NULL.
76 */
77struct xbc_node * __init xbc_node_get_parent(struct xbc_node *node)
78{
79 return node->parent == XBC_NODE_MAX ? NULL : &xbc_nodes[node->parent];
80}
81
82/**
83 * xbc_node_get_child() - Get the child XBC node
84 * @node: An XBC node.
85 *
86 * Return the first child node of @node. If the node has no child, return
87 * NULL.
88 */
89struct xbc_node * __init xbc_node_get_child(struct xbc_node *node)
90{
91 return node->child ? &xbc_nodes[node->child] : NULL;
92}
93
94/**
95 * xbc_node_get_next() - Get the next sibling XBC node
96 * @node: An XBC node.
97 *
98 * Return the NEXT sibling node of @node. If the node has no next sibling,
99 * return NULL. Note that even if this returns NULL, it doesn't mean @node
100 * has no siblings. (You also has to check whether the parent's child node
101 * is @node or not.)
102 */
103struct xbc_node * __init xbc_node_get_next(struct xbc_node *node)
104{
105 return node->next ? &xbc_nodes[node->next] : NULL;
106}
107
108/**
109 * xbc_node_get_data() - Get the data of XBC node
110 * @node: An XBC node.
111 *
112 * Return the data (which is always a null terminated string) of @node.
113 * If the node has invalid data, warn and return NULL.
114 */
115const char * __init xbc_node_get_data(struct xbc_node *node)
116{
117 int offset = node->data & ~XBC_VALUE;
118
119 if (WARN_ON(offset >= xbc_data_size))
120 return NULL;
121
122 return xbc_data + offset;
123}
124
125static bool __init
126xbc_node_match_prefix(struct xbc_node *node, const char **prefix)
127{
128 const char *p = xbc_node_get_data(node);
129 int len = strlen(p);
130
131 if (strncmp(*prefix, p, len))
132 return false;
133
134 p = *prefix + len;
135 if (*p == '.')
136 p++;
137 else if (*p != '\0')
138 return false;
139 *prefix = p;
140
141 return true;
142}
143
144/**
145 * xbc_node_find_child() - Find a child node which matches given key
146 * @parent: An XBC node.
147 * @key: A key string.
148 *
149 * Search a node under @parent which matches @key. The @key can contain
150 * several words jointed with '.'. If @parent is NULL, this searches the
151 * node from whole tree. Return NULL if no node is matched.
152 */
153struct xbc_node * __init
154xbc_node_find_child(struct xbc_node *parent, const char *key)
155{
156 struct xbc_node *node;
157
158 if (parent)
159 node = xbc_node_get_child(parent);
160 else
161 node = xbc_root_node();
162
163 while (node && xbc_node_is_key(node)) {
164 if (!xbc_node_match_prefix(node, &key))
165 node = xbc_node_get_next(node);
166 else if (*key != '\0')
167 node = xbc_node_get_child(node);
168 else
169 break;
170 }
171
172 return node;
173}
174
175/**
176 * xbc_node_find_value() - Find a value node which matches given key
177 * @parent: An XBC node.
178 * @key: A key string.
179 * @vnode: A container pointer of found XBC node.
180 *
181 * Search a value node under @parent whose (parent) key node matches @key,
182 * store it in *@vnode, and returns the value string.
183 * The @key can contain several words jointed with '.'. If @parent is NULL,
184 * this searches the node from whole tree. Return the value string if a
185 * matched key found, return NULL if no node is matched.
186 * Note that this returns 0-length string and stores NULL in *@vnode if the
187 * key has no value. And also it will return the value of the first entry if
188 * the value is an array.
189 */
190const char * __init
191xbc_node_find_value(struct xbc_node *parent, const char *key,
192 struct xbc_node **vnode)
193{
194 struct xbc_node *node = xbc_node_find_child(parent, key);
195
196 if (!node || !xbc_node_is_key(node))
197 return NULL;
198
199 node = xbc_node_get_child(node);
200 if (node && !xbc_node_is_value(node))
201 return NULL;
202
203 if (vnode)
204 *vnode = node;
205
206 return node ? xbc_node_get_data(node) : "";
207}
208
209/**
210 * xbc_node_compose_key_after() - Compose partial key string of the XBC node
211 * @root: Root XBC node
212 * @node: Target XBC node.
213 * @buf: A buffer to store the key.
214 * @size: The size of the @buf.
215 *
216 * Compose the partial key of the @node into @buf, which is starting right
217 * after @root (@root is not included.) If @root is NULL, this returns full
218 * key words of @node.
219 * Returns the total length of the key stored in @buf. Returns -EINVAL
220 * if @node is NULL or @root is not the ancestor of @node or @root is @node,
221 * or returns -ERANGE if the key depth is deeper than max depth.
222 * This is expected to be used with xbc_find_node() to list up all (child)
223 * keys under given key.
224 */
225int __init xbc_node_compose_key_after(struct xbc_node *root,
226 struct xbc_node *node,
227 char *buf, size_t size)
228{
229 u16 keys[XBC_DEPTH_MAX];
230 int depth = 0, ret = 0, total = 0;
231
232 if (!node || node == root)
233 return -EINVAL;
234
235 if (xbc_node_is_value(node))
236 node = xbc_node_get_parent(node);
237
238 while (node && node != root) {
239 keys[depth++] = xbc_node_index(node);
240 if (depth == XBC_DEPTH_MAX)
241 return -ERANGE;
242 node = xbc_node_get_parent(node);
243 }
244 if (!node && root)
245 return -EINVAL;
246
247 while (--depth >= 0) {
248 node = xbc_nodes + keys[depth];
249 ret = snprintf(buf, size, "%s%s", xbc_node_get_data(node),
250 depth ? "." : "");
251 if (ret < 0)
252 return ret;
253 if (ret > size) {
254 size = 0;
255 } else {
256 size -= ret;
257 buf += ret;
258 }
259 total += ret;
260 }
261
262 return total;
263}
264
265/**
266 * xbc_node_find_next_leaf() - Find the next leaf node under given node
267 * @root: An XBC root node
268 * @node: An XBC node which starts from.
269 *
270 * Search the next leaf node (which means the terminal key node) of @node
271 * under @root node (including @root node itself).
272 * Return the next node or NULL if next leaf node is not found.
273 */
274struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root,
275 struct xbc_node *node)
276{
277 if (unlikely(!xbc_data))
278 return NULL;
279
280 if (!node) { /* First try */
281 node = root;
282 if (!node)
283 node = xbc_nodes;
284 } else {
285 if (node == root) /* @root was a leaf, no child node. */
286 return NULL;
287
288 while (!node->next) {
289 node = xbc_node_get_parent(node);
290 if (node == root)
291 return NULL;
292 /* User passed a node which is not uder parent */
293 if (WARN_ON(!node))
294 return NULL;
295 }
296 node = xbc_node_get_next(node);
297 }
298
299 while (node && !xbc_node_is_leaf(node))
300 node = xbc_node_get_child(node);
301
302 return node;
303}
304
305/**
306 * xbc_node_find_next_key_value() - Find the next key-value pair nodes
307 * @root: An XBC root node
308 * @leaf: A container pointer of XBC node which starts from.
309 *
310 * Search the next leaf node (which means the terminal key node) of *@leaf
311 * under @root node. Returns the value and update *@leaf if next leaf node
312 * is found, or NULL if no next leaf node is found.
313 * Note that this returns 0-length string if the key has no value, or
314 * the value of the first entry if the value is an array.
315 */
316const char * __init xbc_node_find_next_key_value(struct xbc_node *root,
317 struct xbc_node **leaf)
318{
319 /* tip must be passed */
320 if (WARN_ON(!leaf))
321 return NULL;
322
323 *leaf = xbc_node_find_next_leaf(root, *leaf);
324 if (!*leaf)
325 return NULL;
326 if ((*leaf)->child)
327 return xbc_node_get_data(xbc_node_get_child(*leaf));
328 else
329 return ""; /* No value key */
330}
331
332/* XBC parse and tree build */
333
334static int __init xbc_init_node(struct xbc_node *node, char *data, u32 flag)
335{
336 unsigned long offset = data - xbc_data;
337
338 if (WARN_ON(offset >= XBC_DATA_MAX))
339 return -EINVAL;
340
341 node->data = (u16)offset | flag;
342 node->child = 0;
343 node->next = 0;
344
345 return 0;
346}
347
348static struct xbc_node * __init xbc_add_node(char *data, u32 flag)
349{
350 struct xbc_node *node;
351
352 if (xbc_node_num == XBC_NODE_MAX)
353 return NULL;
354
355 node = &xbc_nodes[xbc_node_num++];
356 if (xbc_init_node(node, data, flag) < 0)
357 return NULL;
358
359 return node;
360}
361
362static inline __init struct xbc_node *xbc_last_sibling(struct xbc_node *node)
363{
364 while (node->next)
365 node = xbc_node_get_next(node);
366
367 return node;
368}
369
370static struct xbc_node * __init xbc_add_sibling(char *data, u32 flag)
371{
372 struct xbc_node *sib, *node = xbc_add_node(data, flag);
373
374 if (node) {
375 if (!last_parent) {
376 node->parent = XBC_NODE_MAX;
377 sib = xbc_last_sibling(xbc_nodes);
378 sib->next = xbc_node_index(node);
379 } else {
380 node->parent = xbc_node_index(last_parent);
381 if (!last_parent->child) {
382 last_parent->child = xbc_node_index(node);
383 } else {
384 sib = xbc_node_get_child(last_parent);
385 sib = xbc_last_sibling(sib);
386 sib->next = xbc_node_index(node);
387 }
388 }
389 } else
390 xbc_parse_error("Too many nodes", data);
391
392 return node;
393}
394
395static inline __init struct xbc_node *xbc_add_child(char *data, u32 flag)
396{
397 struct xbc_node *node = xbc_add_sibling(data, flag);
398
399 if (node)
400 last_parent = node;
401
402 return node;
403}
404
405static inline __init bool xbc_valid_keyword(char *key)
406{
407 if (key[0] == '\0')
408 return false;
409
410 while (isalnum(*key) || *key == '-' || *key == '_')
411 key++;
412
413 return *key == '\0';
414}
415
416static char *skip_comment(char *p)
417{
418 char *ret;
419
420 ret = strchr(p, '\n');
421 if (!ret)
422 ret = p + strlen(p);
423 else
424 ret++;
425
426 return ret;
427}
428
429static char *skip_spaces_until_newline(char *p)
430{
431 while (isspace(*p) && *p != '\n')
432 p++;
433 return p;
434}
435
436static int __init __xbc_open_brace(char *p)
437{
438 /* Push the last key as open brace */
439 open_brace[brace_index++] = xbc_node_index(last_parent);
440 if (brace_index >= XBC_DEPTH_MAX)
441 return xbc_parse_error("Exceed max depth of braces", p);
442
443 return 0;
444}
445
446static int __init __xbc_close_brace(char *p)
447{
448 brace_index--;
449 if (!last_parent || brace_index < 0 ||
450 (open_brace[brace_index] != xbc_node_index(last_parent)))
451 return xbc_parse_error("Unexpected closing brace", p);
452
453 if (brace_index == 0)
454 last_parent = NULL;
455 else
456 last_parent = &xbc_nodes[open_brace[brace_index - 1]];
457
458 return 0;
459}
460
461/*
462 * Return delimiter or error, no node added. As same as lib/cmdline.c,
463 * you can use " around spaces, but can't escape " for value.
464 */
465static int __init __xbc_parse_value(char **__v, char **__n)
466{
467 char *p, *v = *__v;
468 int c, quotes = 0;
469
470 v = skip_spaces(v);
471 while (*v == '#') {
472 v = skip_comment(v);
473 v = skip_spaces(v);
474 }
475 if (*v == '"' || *v == '\'') {
476 quotes = *v;
477 v++;
478 }
479 p = v - 1;
480 while ((c = *++p)) {
481 if (!isprint(c) && !isspace(c))
482 return xbc_parse_error("Non printable value", p);
483 if (quotes) {
484 if (c != quotes)
485 continue;
486 quotes = 0;
487 *p++ = '\0';
488 p = skip_spaces_until_newline(p);
489 c = *p;
490 if (c && !strchr(",;\n#}", c))
491 return xbc_parse_error("No value delimiter", p);
492 if (*p)
493 p++;
494 break;
495 }
496 if (strchr(",;\n#}", c)) {
497 *p++ = '\0';
498 v = strim(v);
499 break;
500 }
501 }
502 if (quotes)
503 return xbc_parse_error("No closing quotes", p);
504 if (c == '#') {
505 p = skip_comment(p);
506 c = '\n'; /* A comment must be treated as a newline */
507 }
508 *__n = p;
509 *__v = v;
510
511 return c;
512}
513
514static int __init xbc_parse_array(char **__v)
515{
516 struct xbc_node *node;
517 char *next;
518 int c = 0;
519
520 do {
521 c = __xbc_parse_value(__v, &next);
522 if (c < 0)
523 return c;
524
525 node = xbc_add_sibling(*__v, XBC_VALUE);
526 if (!node)
527 return -ENOMEM;
528 *__v = next;
529 } while (c == ',');
530 node->next = 0;
531
532 return c;
533}
534
535static inline __init
536struct xbc_node *find_match_node(struct xbc_node *node, char *k)
537{
538 while (node) {
539 if (!strcmp(xbc_node_get_data(node), k))
540 break;
541 node = xbc_node_get_next(node);
542 }
543 return node;
544}
545
546static int __init __xbc_add_key(char *k)
547{
548 struct xbc_node *node, *child;
549
550 if (!xbc_valid_keyword(k))
551 return xbc_parse_error("Invalid keyword", k);
552
553 if (unlikely(xbc_node_num == 0))
554 goto add_node;
555
556 if (!last_parent) /* the first level */
557 node = find_match_node(xbc_nodes, k);
558 else {
559 child = xbc_node_get_child(last_parent);
560 if (child && xbc_node_is_value(child))
561 return xbc_parse_error("Subkey is mixed with value", k);
562 node = find_match_node(child, k);
563 }
564
565 if (node)
566 last_parent = node;
567 else {
568add_node:
569 node = xbc_add_child(k, XBC_KEY);
570 if (!node)
571 return -ENOMEM;
572 }
573 return 0;
574}
575
576static int __init __xbc_parse_keys(char *k)
577{
578 char *p;
579 int ret;
580
581 k = strim(k);
582 while ((p = strchr(k, '.'))) {
583 *p++ = '\0';
584 ret = __xbc_add_key(k);
585 if (ret)
586 return ret;
587 k = p;
588 }
589
590 return __xbc_add_key(k);
591}
592
593static int __init xbc_parse_kv(char **k, char *v, int op)
594{
595 struct xbc_node *prev_parent = last_parent;
596 struct xbc_node *child;
597 char *next;
598 int c, ret;
599
600 ret = __xbc_parse_keys(*k);
601 if (ret)
602 return ret;
603
604 child = xbc_node_get_child(last_parent);
605 if (child) {
606 if (xbc_node_is_key(child))
607 return xbc_parse_error("Value is mixed with subkey", v);
608 else if (op == '=')
609 return xbc_parse_error("Value is redefined", v);
610 }
611
612 c = __xbc_parse_value(&v, &next);
613 if (c < 0)
614 return c;
615
616 if (op == ':' && child) {
617 xbc_init_node(child, v, XBC_VALUE);
618 } else if (!xbc_add_sibling(v, XBC_VALUE))
619 return -ENOMEM;
620
621 if (c == ',') { /* Array */
622 c = xbc_parse_array(&next);
623 if (c < 0)
624 return c;
625 }
626
627 last_parent = prev_parent;
628
629 if (c == '}') {
630 ret = __xbc_close_brace(next - 1);
631 if (ret < 0)
632 return ret;
633 }
634
635 *k = next;
636
637 return 0;
638}
639
640static int __init xbc_parse_key(char **k, char *n)
641{
642 struct xbc_node *prev_parent = last_parent;
643 int ret;
644
645 *k = strim(*k);
646 if (**k != '\0') {
647 ret = __xbc_parse_keys(*k);
648 if (ret)
649 return ret;
650 last_parent = prev_parent;
651 }
652 *k = n;
653
654 return 0;
655}
656
657static int __init xbc_open_brace(char **k, char *n)
658{
659 int ret;
660
661 ret = __xbc_parse_keys(*k);
662 if (ret)
663 return ret;
664 *k = n;
665
666 return __xbc_open_brace(n - 1);
667}
668
669static int __init xbc_close_brace(char **k, char *n)
670{
671 int ret;
672
673 ret = xbc_parse_key(k, n);
674 if (ret)
675 return ret;
676 /* k is updated in xbc_parse_key() */
677
678 return __xbc_close_brace(n - 1);
679}
680
681static int __init xbc_verify_tree(void)
682{
683 int i, depth, len, wlen;
684 struct xbc_node *n, *m;
685
686 /* Brace closing */
687 if (brace_index) {
688 n = &xbc_nodes[open_brace[brace_index]];
689 return xbc_parse_error("Brace is not closed",
690 xbc_node_get_data(n));
691 }
692
693 /* Empty tree */
694 if (xbc_node_num == 0) {
695 xbc_parse_error("Empty config", xbc_data);
696 return -ENOENT;
697 }
698
699 for (i = 0; i < xbc_node_num; i++) {
700 if (xbc_nodes[i].next > xbc_node_num) {
701 return xbc_parse_error("No closing brace",
702 xbc_node_get_data(xbc_nodes + i));
703 }
704 }
705
706 /* Key tree limitation check */
707 n = &xbc_nodes[0];
708 depth = 1;
709 len = 0;
710
711 while (n) {
712 wlen = strlen(xbc_node_get_data(n)) + 1;
713 len += wlen;
714 if (len > XBC_KEYLEN_MAX)
715 return xbc_parse_error("Too long key length",
716 xbc_node_get_data(n));
717
718 m = xbc_node_get_child(n);
719 if (m && xbc_node_is_key(m)) {
720 n = m;
721 depth++;
722 if (depth > XBC_DEPTH_MAX)
723 return xbc_parse_error("Too many key words",
724 xbc_node_get_data(n));
725 continue;
726 }
727 len -= wlen;
728 m = xbc_node_get_next(n);
729 while (!m) {
730 n = xbc_node_get_parent(n);
731 if (!n)
732 break;
733 len -= strlen(xbc_node_get_data(n)) + 1;
734 depth--;
735 m = xbc_node_get_next(n);
736 }
737 n = m;
738 }
739
740 return 0;
741}
742
743/**
744 * xbc_destroy_all() - Clean up all parsed bootconfig
745 *
746 * This clears all data structures of parsed bootconfig on memory.
747 * If you need to reuse xbc_init() with new boot config, you can
748 * use this.
749 */
750void __init xbc_destroy_all(void)
751{
752 xbc_data = NULL;
753 xbc_data_size = 0;
754 xbc_node_num = 0;
755 memblock_free(__pa(xbc_nodes), sizeof(struct xbc_node) * XBC_NODE_MAX);
756 xbc_nodes = NULL;
757 brace_index = 0;
758}
759
760/**
761 * xbc_init() - Parse given XBC file and build XBC internal tree
762 * @buf: boot config text
763 * @emsg: A pointer of const char * to store the error message
764 * @epos: A pointer of int to store the error position
765 *
766 * This parses the boot config text in @buf. @buf must be a
767 * null terminated string and smaller than XBC_DATA_MAX.
768 * Return the number of stored nodes (>0) if succeeded, or -errno
769 * if there is any error.
770 * In error cases, @emsg will be updated with an error message and
771 * @epos will be updated with the error position which is the byte offset
772 * of @buf. If the error is not a parser error, @epos will be -1.
773 */
774int __init xbc_init(char *buf, const char **emsg, int *epos)
775{
776 char *p, *q;
777 int ret, c;
778
779 if (epos)
780 *epos = -1;
781
782 if (xbc_data) {
783 if (emsg)
784 *emsg = "Bootconfig is already initialized";
785 return -EBUSY;
786 }
787
788 ret = strlen(buf);
789 if (ret > XBC_DATA_MAX - 1 || ret == 0) {
790 if (emsg)
791 *emsg = ret ? "Config data is too big" :
792 "Config data is empty";
793 return -ERANGE;
794 }
795
796 xbc_nodes = memblock_alloc(sizeof(struct xbc_node) * XBC_NODE_MAX,
797 SMP_CACHE_BYTES);
798 if (!xbc_nodes) {
799 if (emsg)
800 *emsg = "Failed to allocate bootconfig nodes";
801 return -ENOMEM;
802 }
803 memset(xbc_nodes, 0, sizeof(struct xbc_node) * XBC_NODE_MAX);
804 xbc_data = buf;
805 xbc_data_size = ret + 1;
806 last_parent = NULL;
807
808 p = buf;
809 do {
810 q = strpbrk(p, "{}=+;:\n#");
811 if (!q) {
812 p = skip_spaces(p);
813 if (*p != '\0')
814 ret = xbc_parse_error("No delimiter", p);
815 break;
816 }
817
818 c = *q;
819 *q++ = '\0';
820 switch (c) {
821 case ':':
822 case '+':
823 if (*q++ != '=') {
824 ret = xbc_parse_error(c == '+' ?
825 "Wrong '+' operator" :
826 "Wrong ':' operator",
827 q - 2);
828 break;
829 }
830 /* fall through */
831 case '=':
832 ret = xbc_parse_kv(&p, q, c);
833 break;
834 case '{':
835 ret = xbc_open_brace(&p, q);
836 break;
837 case '#':
838 q = skip_comment(q);
839 /* fall through */
840 case ';':
841 case '\n':
842 ret = xbc_parse_key(&p, q);
843 break;
844 case '}':
845 ret = xbc_close_brace(&p, q);
846 break;
847 }
848 } while (!ret);
849
850 if (!ret)
851 ret = xbc_verify_tree();
852
853 if (ret < 0) {
854 if (epos)
855 *epos = xbc_err_pos;
856 if (emsg)
857 *emsg = xbc_err_msg;
858 xbc_destroy_all();
859 } else
860 ret = xbc_node_num;
861
862 return ret;
863}
864
865/**
866 * xbc_debug_dump() - Dump current XBC node list
867 *
868 * Dump the current XBC node list on printk buffer for debug.
869 */
870void __init xbc_debug_dump(void)
871{
872 int i;
873
874 for (i = 0; i < xbc_node_num; i++) {
875 pr_debug("[%d] %s (%s) .next=%d, .child=%d .parent=%d\n", i,
876 xbc_node_get_data(xbc_nodes + i),
877 xbc_node_is_value(xbc_nodes + i) ? "value" : "key",
878 xbc_nodes[i].next, xbc_nodes[i].child,
879 xbc_nodes[i].parent);
880 }
881}