1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Extra Boot Config
4 * Masami Hiramatsu <mhiramat@kernel.org>
5 */
6
7#ifdef __KERNEL__
8#include <linux/bootconfig.h>
9#include <linux/bug.h>
10#include <linux/ctype.h>
11#include <linux/errno.h>
12#include <linux/kernel.h>
13#include <linux/memblock.h>
14#include <linux/string.h>
15
16#ifdef CONFIG_BOOT_CONFIG_EMBED
17/* embedded_bootconfig_data is defined in bootconfig-data.S */
18extern __visible const char embedded_bootconfig_data[];
19extern __visible const char embedded_bootconfig_data_end[];
20
21const char * __init xbc_get_embedded_bootconfig(size_t *size)
22{
23 *size = embedded_bootconfig_data_end - embedded_bootconfig_data;
24 return (*size) ? embedded_bootconfig_data : NULL;
25}
26#endif
27
28#else /* !__KERNEL__ */
29/*
30 * NOTE: This is only for tools/bootconfig, because tools/bootconfig will
31 * run the parser sanity test.
32 * This does NOT mean lib/bootconfig.c is available in the user space.
33 * However, if you change this file, please make sure the tools/bootconfig
34 * has no issue on building and running.
35 */
36#include <linux/bootconfig.h>
37#endif
38
39/*
40 * Extra Boot Config (XBC) is given as tree-structured ascii text of
41 * key-value pairs on memory.
42 * xbc_parse() parses the text to build a simple tree. Each tree node is
43 * simply a key word or a value. A key node may have a next key node or/and
44 * a child node (both key and value). A value node may have a next value
45 * node (for array).
46 */
47
48static struct xbc_node *xbc_nodes __initdata;
49static int xbc_node_num __initdata;
50static char *xbc_data __initdata;
51static size_t xbc_data_size __initdata;
52static struct xbc_node *last_parent __initdata;
53static const char *xbc_err_msg __initdata;
54static int xbc_err_pos __initdata;
55static int open_brace[XBC_DEPTH_MAX] __initdata;
56static int brace_index __initdata;
57
58#ifdef __KERNEL__
59static inline void * __init xbc_alloc_mem(size_t size)
60{
61 return memblock_alloc(size, SMP_CACHE_BYTES);
62}
63
64static inline void __init xbc_free_mem(void *addr, size_t size, bool early)
65{
66 if (early)
67 memblock_free(ptr: addr, size);
68 else if (addr)
69 memblock_free_late(__pa(addr), size);
70}
71
72#else /* !__KERNEL__ */
73
74static inline void *xbc_alloc_mem(size_t size)
75{
76 return malloc(size);
77}
78
79static inline void xbc_free_mem(void *addr, size_t size, bool early)
80{
81 free(addr);
82}
83#endif
84/**
85 * xbc_get_info() - Get the information of loaded boot config
86 * @node_size: A pointer to store the number of nodes.
87 * @data_size: A pointer to store the size of bootconfig data.
88 *
89 * Get the number of used nodes in @node_size if it is not NULL,
90 * and the size of bootconfig data in @data_size if it is not NULL.
91 * Return 0 if the boot config is initialized, or return -ENODEV.
92 */
93int __init xbc_get_info(int *node_size, size_t *data_size)
94{
95 if (!xbc_data)
96 return -ENODEV;
97
98 if (node_size)
99 *node_size = xbc_node_num;
100 if (data_size)
101 *data_size = xbc_data_size;
102 return 0;
103}
104
105static int __init xbc_parse_error(const char *msg, const char *p)
106{
107 xbc_err_msg = msg;
108 xbc_err_pos = (int)(p - xbc_data);
109
110 return -EINVAL;
111}
112
113/**
114 * xbc_root_node() - Get the root node of extended boot config
115 *
116 * Return the address of root node of extended boot config. If the
117 * extended boot config is not initiized, return NULL.
118 */
119struct xbc_node * __init xbc_root_node(void)
120{
121 if (unlikely(!xbc_data))
122 return NULL;
123
124 return xbc_nodes;
125}
126
127/**
128 * xbc_node_index() - Get the index of XBC node
129 * @node: A target node of getting index.
130 *
131 * Return the index number of @node in XBC node list.
132 */
133int __init xbc_node_index(struct xbc_node *node)
134{
135 return node - &xbc_nodes[0];
136}
137
138/**
139 * xbc_node_get_parent() - Get the parent XBC node
140 * @node: An XBC node.
141 *
142 * Return the parent node of @node. If the node is top node of the tree,
143 * return NULL.
144 */
145struct xbc_node * __init xbc_node_get_parent(struct xbc_node *node)
146{
147 return node->parent == XBC_NODE_MAX ? NULL : &xbc_nodes[node->parent];
148}
149
150/**
151 * xbc_node_get_child() - Get the child XBC node
152 * @node: An XBC node.
153 *
154 * Return the first child node of @node. If the node has no child, return
155 * NULL.
156 */
157struct xbc_node * __init xbc_node_get_child(struct xbc_node *node)
158{
159 return node->child ? &xbc_nodes[node->child] : NULL;
160}
161
162/**
163 * xbc_node_get_next() - Get the next sibling XBC node
164 * @node: An XBC node.
165 *
166 * Return the NEXT sibling node of @node. If the node has no next sibling,
167 * return NULL. Note that even if this returns NULL, it doesn't mean @node
168 * has no siblings. (You also has to check whether the parent's child node
169 * is @node or not.)
170 */
171struct xbc_node * __init xbc_node_get_next(struct xbc_node *node)
172{
173 return node->next ? &xbc_nodes[node->next] : NULL;
174}
175
176/**
177 * xbc_node_get_data() - Get the data of XBC node
178 * @node: An XBC node.
179 *
180 * Return the data (which is always a null terminated string) of @node.
181 * If the node has invalid data, warn and return NULL.
182 */
183const char * __init xbc_node_get_data(struct xbc_node *node)
184{
185 int offset = node->data & ~XBC_VALUE;
186
187 if (WARN_ON(offset >= xbc_data_size))
188 return NULL;
189
190 return xbc_data + offset;
191}
192
193static bool __init
194xbc_node_match_prefix(struct xbc_node *node, const char **prefix)
195{
196 const char *p = xbc_node_get_data(node);
197 int len = strlen(p);
198
199 if (strncmp(*prefix, p, len))
200 return false;
201
202 p = *prefix + len;
203 if (*p == '.')
204 p++;
205 else if (*p != '\0')
206 return false;
207 *prefix = p;
208
209 return true;
210}
211
212/**
213 * xbc_node_find_subkey() - Find a subkey node which matches given key
214 * @parent: An XBC node.
215 * @key: A key string.
216 *
217 * Search a key node under @parent which matches @key. The @key can contain
218 * several words jointed with '.'. If @parent is NULL, this searches the
219 * node from whole tree. Return NULL if no node is matched.
220 */
221struct xbc_node * __init
222xbc_node_find_subkey(struct xbc_node *parent, const char *key)
223{
224 struct xbc_node *node;
225
226 if (parent)
227 node = xbc_node_get_subkey(node: parent);
228 else
229 node = xbc_root_node();
230
231 while (node && xbc_node_is_key(node)) {
232 if (!xbc_node_match_prefix(node, prefix: &key))
233 node = xbc_node_get_next(node);
234 else if (*key != '\0')
235 node = xbc_node_get_subkey(node);
236 else
237 break;
238 }
239
240 return node;
241}
242
243/**
244 * xbc_node_find_value() - Find a value node which matches given key
245 * @parent: An XBC node.
246 * @key: A key string.
247 * @vnode: A container pointer of found XBC node.
248 *
249 * Search a value node under @parent whose (parent) key node matches @key,
250 * store it in *@vnode, and returns the value string.
251 * The @key can contain several words jointed with '.'. If @parent is NULL,
252 * this searches the node from whole tree. Return the value string if a
253 * matched key found, return NULL if no node is matched.
254 * Note that this returns 0-length string and stores NULL in *@vnode if the
255 * key has no value. And also it will return the value of the first entry if
256 * the value is an array.
257 */
258const char * __init
259xbc_node_find_value(struct xbc_node *parent, const char *key,
260 struct xbc_node **vnode)
261{
262 struct xbc_node *node = xbc_node_find_subkey(parent, key);
263
264 if (!node || !xbc_node_is_key(node))
265 return NULL;
266
267 node = xbc_node_get_child(node);
268 if (node && !xbc_node_is_value(node))
269 return NULL;
270
271 if (vnode)
272 *vnode = node;
273
274 return node ? xbc_node_get_data(node) : "";
275}
276
277/**
278 * xbc_node_compose_key_after() - Compose partial key string of the XBC node
279 * @root: Root XBC node
280 * @node: Target XBC node.
281 * @buf: A buffer to store the key.
282 * @size: The size of the @buf.
283 *
284 * Compose the partial key of the @node into @buf, which is starting right
285 * after @root (@root is not included.) If @root is NULL, this returns full
286 * key words of @node.
287 * Returns the total length of the key stored in @buf. Returns -EINVAL
288 * if @node is NULL or @root is not the ancestor of @node or @root is @node,
289 * or returns -ERANGE if the key depth is deeper than max depth.
290 * This is expected to be used with xbc_find_node() to list up all (child)
291 * keys under given key.
292 */
293int __init xbc_node_compose_key_after(struct xbc_node *root,
294 struct xbc_node *node,
295 char *buf, size_t size)
296{
297 uint16_t keys[XBC_DEPTH_MAX];
298 int depth = 0, ret = 0, total = 0;
299
300 if (!node || node == root)
301 return -EINVAL;
302
303 if (xbc_node_is_value(node))
304 node = xbc_node_get_parent(node);
305
306 while (node && node != root) {
307 keys[depth++] = xbc_node_index(node);
308 if (depth == XBC_DEPTH_MAX)
309 return -ERANGE;
310 node = xbc_node_get_parent(node);
311 }
312 if (!node && root)
313 return -EINVAL;
314
315 while (--depth >= 0) {
316 node = xbc_nodes + keys[depth];
317 ret = snprintf(buf, size, fmt: "%s%s", xbc_node_get_data(node),
318 depth ? "." : "");
319 if (ret < 0)
320 return ret;
321 if (ret > size) {
322 size = 0;
323 } else {
324 size -= ret;
325 buf += ret;
326 }
327 total += ret;
328 }
329
330 return total;
331}
332
333/**
334 * xbc_node_find_next_leaf() - Find the next leaf node under given node
335 * @root: An XBC root node
336 * @node: An XBC node which starts from.
337 *
338 * Search the next leaf node (which means the terminal key node) of @node
339 * under @root node (including @root node itself).
340 * Return the next node or NULL if next leaf node is not found.
341 */
342struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root,
343 struct xbc_node *node)
344{
345 struct xbc_node *next;
346
347 if (unlikely(!xbc_data))
348 return NULL;
349
350 if (!node) { /* First try */
351 node = root;
352 if (!node)
353 node = xbc_nodes;
354 } else {
355 /* Leaf node may have a subkey */
356 next = xbc_node_get_subkey(node);
357 if (next) {
358 node = next;
359 goto found;
360 }
361
362 if (node == root) /* @root was a leaf, no child node. */
363 return NULL;
364
365 while (!node->next) {
366 node = xbc_node_get_parent(node);
367 if (node == root)
368 return NULL;
369 /* User passed a node which is not uder parent */
370 if (WARN_ON(!node))
371 return NULL;
372 }
373 node = xbc_node_get_next(node);
374 }
375
376found:
377 while (node && !xbc_node_is_leaf(node))
378 node = xbc_node_get_child(node);
379
380 return node;
381}
382
383/**
384 * xbc_node_find_next_key_value() - Find the next key-value pair nodes
385 * @root: An XBC root node
386 * @leaf: A container pointer of XBC node which starts from.
387 *
388 * Search the next leaf node (which means the terminal key node) of *@leaf
389 * under @root node. Returns the value and update *@leaf if next leaf node
390 * is found, or NULL if no next leaf node is found.
391 * Note that this returns 0-length string if the key has no value, or
392 * the value of the first entry if the value is an array.
393 */
394const char * __init xbc_node_find_next_key_value(struct xbc_node *root,
395 struct xbc_node **leaf)
396{
397 /* tip must be passed */
398 if (WARN_ON(!leaf))
399 return NULL;
400
401 *leaf = xbc_node_find_next_leaf(root, node: *leaf);
402 if (!*leaf)
403 return NULL;
404 if ((*leaf)->child)
405 return xbc_node_get_data(node: xbc_node_get_child(node: *leaf));
406 else
407 return ""; /* No value key */
408}
409
410/* XBC parse and tree build */
411
412static int __init xbc_init_node(struct xbc_node *node, char *data, uint32_t flag)
413{
414 unsigned long offset = data - xbc_data;
415
416 if (WARN_ON(offset >= XBC_DATA_MAX))
417 return -EINVAL;
418
419 node->data = (uint16_t)offset | flag;
420 node->child = 0;
421 node->next = 0;
422
423 return 0;
424}
425
426static struct xbc_node * __init xbc_add_node(char *data, uint32_t flag)
427{
428 struct xbc_node *node;
429
430 if (xbc_node_num == XBC_NODE_MAX)
431 return NULL;
432
433 node = &xbc_nodes[xbc_node_num++];
434 if (xbc_init_node(node, data, flag) < 0)
435 return NULL;
436
437 return node;
438}
439
440static inline __init struct xbc_node *xbc_last_sibling(struct xbc_node *node)
441{
442 while (node->next)
443 node = xbc_node_get_next(node);
444
445 return node;
446}
447
448static inline __init struct xbc_node *xbc_last_child(struct xbc_node *node)
449{
450 while (node->child)
451 node = xbc_node_get_child(node);
452
453 return node;
454}
455
456static struct xbc_node * __init __xbc_add_sibling(char *data, uint32_t flag, bool head)
457{
458 struct xbc_node *sib, *node = xbc_add_node(data, flag);
459
460 if (node) {
461 if (!last_parent) {
462 /* Ignore @head in this case */
463 node->parent = XBC_NODE_MAX;
464 sib = xbc_last_sibling(node: xbc_nodes);
465 sib->next = xbc_node_index(node);
466 } else {
467 node->parent = xbc_node_index(node: last_parent);
468 if (!last_parent->child || head) {
469 node->next = last_parent->child;
470 last_parent->child = xbc_node_index(node);
471 } else {
472 sib = xbc_node_get_child(node: last_parent);
473 sib = xbc_last_sibling(node: sib);
474 sib->next = xbc_node_index(node);
475 }
476 }
477 } else
478 xbc_parse_error(msg: "Too many nodes", p: data);
479
480 return node;
481}
482
483static inline struct xbc_node * __init xbc_add_sibling(char *data, uint32_t flag)
484{
485 return __xbc_add_sibling(data, flag, head: false);
486}
487
488static inline struct xbc_node * __init xbc_add_head_sibling(char *data, uint32_t flag)
489{
490 return __xbc_add_sibling(data, flag, head: true);
491}
492
493static inline __init struct xbc_node *xbc_add_child(char *data, uint32_t flag)
494{
495 struct xbc_node *node = xbc_add_sibling(data, flag);
496
497 if (node)
498 last_parent = node;
499
500 return node;
501}
502
503static inline __init bool xbc_valid_keyword(char *key)
504{
505 if (key[0] == '\0')
506 return false;
507
508 while (isalnum(*key) || *key == '-' || *key == '_')
509 key++;
510
511 return *key == '\0';
512}
513
514static char *skip_comment(char *p)
515{
516 char *ret;
517
518 ret = strchr(p, '\n');
519 if (!ret)
520 ret = p + strlen(p);
521 else
522 ret++;
523
524 return ret;
525}
526
527static char *skip_spaces_until_newline(char *p)
528{
529 while (isspace(*p) && *p != '\n')
530 p++;
531 return p;
532}
533
534static int __init __xbc_open_brace(char *p)
535{
536 /* Push the last key as open brace */
537 open_brace[brace_index++] = xbc_node_index(node: last_parent);
538 if (brace_index >= XBC_DEPTH_MAX)
539 return xbc_parse_error(msg: "Exceed max depth of braces", p);
540
541 return 0;
542}
543
544static int __init __xbc_close_brace(char *p)
545{
546 brace_index--;
547 if (!last_parent || brace_index < 0 ||
548 (open_brace[brace_index] != xbc_node_index(node: last_parent)))
549 return xbc_parse_error(msg: "Unexpected closing brace", p);
550
551 if (brace_index == 0)
552 last_parent = NULL;
553 else
554 last_parent = &xbc_nodes[open_brace[brace_index - 1]];
555
556 return 0;
557}
558
559/*
560 * Return delimiter or error, no node added. As same as lib/cmdline.c,
561 * you can use " around spaces, but can't escape " for value.
562 */
563static int __init __xbc_parse_value(char **__v, char **__n)
564{
565 char *p, *v = *__v;
566 int c, quotes = 0;
567
568 v = skip_spaces(v);
569 while (*v == '#') {
570 v = skip_comment(p: v);
571 v = skip_spaces(v);
572 }
573 if (*v == '"' || *v == '\'') {
574 quotes = *v;
575 v++;
576 }
577 p = v - 1;
578 while ((c = *++p)) {
579 if (!isprint(c) && !isspace(c))
580 return xbc_parse_error(msg: "Non printable value", p);
581 if (quotes) {
582 if (c != quotes)
583 continue;
584 quotes = 0;
585 *p++ = '\0';
586 p = skip_spaces_until_newline(p);
587 c = *p;
588 if (c && !strchr(",;\n#}", c))
589 return xbc_parse_error(msg: "No value delimiter", p);
590 if (*p)
591 p++;
592 break;
593 }
594 if (strchr(",;\n#}", c)) {
595 *p++ = '\0';
596 v = strim(v);
597 break;
598 }
599 }
600 if (quotes)
601 return xbc_parse_error(msg: "No closing quotes", p);
602 if (c == '#') {
603 p = skip_comment(p);
604 c = '\n'; /* A comment must be treated as a newline */
605 }
606 *__n = p;
607 *__v = v;
608
609 return c;
610}
611
612static int __init xbc_parse_array(char **__v)
613{
614 struct xbc_node *node;
615 char *next;
616 int c = 0;
617
618 if (last_parent->child)
619 last_parent = xbc_node_get_child(node: last_parent);
620
621 do {
622 c = __xbc_parse_value(__v, n: &next);
623 if (c < 0)
624 return c;
625
626 node = xbc_add_child(data: *__v, XBC_VALUE);
627 if (!node)
628 return -ENOMEM;
629 *__v = next;
630 } while (c == ',');
631 node->child = 0;
632
633 return c;
634}
635
636static inline __init
637struct xbc_node *find_match_node(struct xbc_node *node, char *k)
638{
639 while (node) {
640 if (!strcmp(xbc_node_get_data(node), k))
641 break;
642 node = xbc_node_get_next(node);
643 }
644 return node;
645}
646
647static int __init __xbc_add_key(char *k)
648{
649 struct xbc_node *node, *child;
650
651 if (!xbc_valid_keyword(key: k))
652 return xbc_parse_error(msg: "Invalid keyword", p: k);
653
654 if (unlikely(xbc_node_num == 0))
655 goto add_node;
656
657 if (!last_parent) /* the first level */
658 node = find_match_node(node: xbc_nodes, k);
659 else {
660 child = xbc_node_get_child(node: last_parent);
661 /* Since the value node is the first child, skip it. */
662 if (child && xbc_node_is_value(node: child))
663 child = xbc_node_get_next(node: child);
664 node = find_match_node(node: child, k);
665 }
666
667 if (node)
668 last_parent = node;
669 else {
670add_node:
671 node = xbc_add_child(data: k, XBC_KEY);
672 if (!node)
673 return -ENOMEM;
674 }
675 return 0;
676}
677
678static int __init __xbc_parse_keys(char *k)
679{
680 char *p;
681 int ret;
682
683 k = strim(k);
684 while ((p = strchr(k, '.'))) {
685 *p++ = '\0';
686 ret = __xbc_add_key(k);
687 if (ret)
688 return ret;
689 k = p;
690 }
691
692 return __xbc_add_key(k);
693}
694
695static int __init xbc_parse_kv(char **k, char *v, int op)
696{
697 struct xbc_node *prev_parent = last_parent;
698 struct xbc_node *child;
699 char *next;
700 int c, ret;
701
702 ret = __xbc_parse_keys(k: *k);
703 if (ret)
704 return ret;
705
706 c = __xbc_parse_value(v: &v, n: &next);
707 if (c < 0)
708 return c;
709
710 child = xbc_node_get_child(node: last_parent);
711 if (child && xbc_node_is_value(node: child)) {
712 if (op == '=')
713 return xbc_parse_error(msg: "Value is redefined", p: v);
714 if (op == ':') {
715 unsigned short nidx = child->next;
716
717 xbc_init_node(node: child, data: v, XBC_VALUE);
718 child->next = nidx; /* keep subkeys */
719 goto array;
720 }
721 /* op must be '+' */
722 last_parent = xbc_last_child(node: child);
723 }
724 /* The value node should always be the first child */
725 if (!xbc_add_head_sibling(data: v, XBC_VALUE))
726 return -ENOMEM;
727
728array:
729 if (c == ',') { /* Array */
730 c = xbc_parse_array(v: &next);
731 if (c < 0)
732 return c;
733 }
734
735 last_parent = prev_parent;
736
737 if (c == '}') {
738 ret = __xbc_close_brace(p: next - 1);
739 if (ret < 0)
740 return ret;
741 }
742
743 *k = next;
744
745 return 0;
746}
747
748static int __init xbc_parse_key(char **k, char *n)
749{
750 struct xbc_node *prev_parent = last_parent;
751 int ret;
752
753 *k = strim(*k);
754 if (**k != '\0') {
755 ret = __xbc_parse_keys(k: *k);
756 if (ret)
757 return ret;
758 last_parent = prev_parent;
759 }
760 *k = n;
761
762 return 0;
763}
764
765static int __init xbc_open_brace(char **k, char *n)
766{
767 int ret;
768
769 ret = __xbc_parse_keys(k: *k);
770 if (ret)
771 return ret;
772 *k = n;
773
774 return __xbc_open_brace(p: n - 1);
775}
776
777static int __init xbc_close_brace(char **k, char *n)
778{
779 int ret;
780
781 ret = xbc_parse_key(k, n);
782 if (ret)
783 return ret;
784 /* k is updated in xbc_parse_key() */
785
786 return __xbc_close_brace(p: n - 1);
787}
788
789static int __init xbc_verify_tree(void)
790{
791 int i, depth, len, wlen;
792 struct xbc_node *n, *m;
793
794 /* Brace closing */
795 if (brace_index) {
796 n = &xbc_nodes[open_brace[brace_index]];
797 return xbc_parse_error(msg: "Brace is not closed",
798 p: xbc_node_get_data(node: n));
799 }
800
801 /* Empty tree */
802 if (xbc_node_num == 0) {
803 xbc_parse_error(msg: "Empty config", p: xbc_data);
804 return -ENOENT;
805 }
806
807 for (i = 0; i < xbc_node_num; i++) {
808 if (xbc_nodes[i].next > xbc_node_num) {
809 return xbc_parse_error(msg: "No closing brace",
810 p: xbc_node_get_data(node: xbc_nodes + i));
811 }
812 }
813
814 /* Key tree limitation check */
815 n = &xbc_nodes[0];
816 depth = 1;
817 len = 0;
818
819 while (n) {
820 wlen = strlen(xbc_node_get_data(n)) + 1;
821 len += wlen;
822 if (len > XBC_KEYLEN_MAX)
823 return xbc_parse_error(msg: "Too long key length",
824 p: xbc_node_get_data(node: n));
825
826 m = xbc_node_get_child(node: n);
827 if (m && xbc_node_is_key(node: m)) {
828 n = m;
829 depth++;
830 if (depth > XBC_DEPTH_MAX)
831 return xbc_parse_error(msg: "Too many key words",
832 p: xbc_node_get_data(node: n));
833 continue;
834 }
835 len -= wlen;
836 m = xbc_node_get_next(node: n);
837 while (!m) {
838 n = xbc_node_get_parent(node: n);
839 if (!n)
840 break;
841 len -= strlen(xbc_node_get_data(n)) + 1;
842 depth--;
843 m = xbc_node_get_next(node: n);
844 }
845 n = m;
846 }
847
848 return 0;
849}
850
851/* Need to setup xbc_data and xbc_nodes before call this. */
852static int __init xbc_parse_tree(void)
853{
854 char *p, *q;
855 int ret = 0, c;
856
857 last_parent = NULL;
858 p = xbc_data;
859 do {
860 q = strpbrk(p, "{}=+;:\n#");
861 if (!q) {
862 p = skip_spaces(p);
863 if (*p != '\0')
864 ret = xbc_parse_error(msg: "No delimiter", p);
865 break;
866 }
867
868 c = *q;
869 *q++ = '\0';
870 switch (c) {
871 case ':':
872 case '+':
873 if (*q++ != '=') {
874 ret = xbc_parse_error(msg: c == '+' ?
875 "Wrong '+' operator" :
876 "Wrong ':' operator",
877 p: q - 2);
878 break;
879 }
880 fallthrough;
881 case '=':
882 ret = xbc_parse_kv(k: &p, v: q, op: c);
883 break;
884 case '{':
885 ret = xbc_open_brace(k: &p, n: q);
886 break;
887 case '#':
888 q = skip_comment(p: q);
889 fallthrough;
890 case ';':
891 case '\n':
892 ret = xbc_parse_key(k: &p, n: q);
893 break;
894 case '}':
895 ret = xbc_close_brace(k: &p, n: q);
896 break;
897 }
898 } while (!ret);
899
900 return ret;
901}
902
903/**
904 * _xbc_exit() - Clean up all parsed bootconfig
905 * @early: Set true if this is called before budy system is initialized.
906 *
907 * This clears all data structures of parsed bootconfig on memory.
908 * If you need to reuse xbc_init() with new boot config, you can
909 * use this.
910 */
911void __init _xbc_exit(bool early)
912{
913 xbc_free_mem(addr: xbc_data, size: xbc_data_size, early);
914 xbc_data = NULL;
915 xbc_data_size = 0;
916 xbc_node_num = 0;
917 xbc_free_mem(addr: xbc_nodes, size: sizeof(struct xbc_node) * XBC_NODE_MAX, early);
918 xbc_nodes = NULL;
919 brace_index = 0;
920}
921
922/**
923 * xbc_init() - Parse given XBC file and build XBC internal tree
924 * @data: The boot config text original data
925 * @size: The size of @data
926 * @emsg: A pointer of const char * to store the error message
927 * @epos: A pointer of int to store the error position
928 *
929 * This parses the boot config text in @data. @size must be smaller
930 * than XBC_DATA_MAX.
931 * Return the number of stored nodes (>0) if succeeded, or -errno
932 * if there is any error.
933 * In error cases, @emsg will be updated with an error message and
934 * @epos will be updated with the error position which is the byte offset
935 * of @buf. If the error is not a parser error, @epos will be -1.
936 */
937int __init xbc_init(const char *data, size_t size, const char **emsg, int *epos)
938{
939 int ret;
940
941 if (epos)
942 *epos = -1;
943
944 if (xbc_data) {
945 if (emsg)
946 *emsg = "Bootconfig is already initialized";
947 return -EBUSY;
948 }
949 if (size > XBC_DATA_MAX || size == 0) {
950 if (emsg)
951 *emsg = size ? "Config data is too big" :
952 "Config data is empty";
953 return -ERANGE;
954 }
955
956 xbc_data = xbc_alloc_mem(size: size + 1);
957 if (!xbc_data) {
958 if (emsg)
959 *emsg = "Failed to allocate bootconfig data";
960 return -ENOMEM;
961 }
962 memcpy(xbc_data, data, size);
963 xbc_data[size] = '\0';
964 xbc_data_size = size + 1;
965
966 xbc_nodes = xbc_alloc_mem(size: sizeof(struct xbc_node) * XBC_NODE_MAX);
967 if (!xbc_nodes) {
968 if (emsg)
969 *emsg = "Failed to allocate bootconfig nodes";
970 _xbc_exit(early: true);
971 return -ENOMEM;
972 }
973 memset(xbc_nodes, 0, sizeof(struct xbc_node) * XBC_NODE_MAX);
974
975 ret = xbc_parse_tree();
976 if (!ret)
977 ret = xbc_verify_tree();
978
979 if (ret < 0) {
980 if (epos)
981 *epos = xbc_err_pos;
982 if (emsg)
983 *emsg = xbc_err_msg;
984 _xbc_exit(early: true);
985 } else
986 ret = xbc_node_num;
987
988 return ret;
989}
990

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source code of linux/lib/bootconfig.c