summaryrefslogtreecommitdiff
path: root/lib/bootconfig.c
blob: afb2e767e6fe83b7ce42f29aba58c935c6b709cb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
// SPDX-License-Identifier: GPL-2.0
/*
 * Extra Boot Config
 * Masami Hiramatsu <mhiramat@kernel.org>
 */

#define pr_fmt(fmt)    "bootconfig: " fmt

#include <linux/bug.h>
#include <linux/ctype.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/printk.h>
#include <linux/bootconfig.h>
#include <linux/string.h>

/*
 * Extra Boot Config (XBC) is given as tree-structured ascii text of
 * key-value pairs on memory.
 * xbc_parse() parses the text to build a simple tree. Each tree node is
 * simply a key word or a value. A key node may have a next key node or/and
 * a child node (both key and value). A value node may have a next value
 * node (for array).
 */

static struct xbc_node xbc_nodes[XBC_NODE_MAX] __initdata;
static int xbc_node_num __initdata;
static char *xbc_data __initdata;
static size_t xbc_data_size __initdata;
static struct xbc_node *last_parent __initdata;

static int __init xbc_parse_error(const char *msg, const char *p)
{
	int pos = p - xbc_data;

	pr_err("Parse error at pos %d: %s\n", pos, msg);
	return -EINVAL;
}

/**
 * xbc_root_node() - Get the root node of extended boot config
 *
 * Return the address of root node of extended boot config. If the
 * extended boot config is not initiized, return NULL.
 */
struct xbc_node * __init xbc_root_node(void)
{
	if (unlikely(!xbc_data))
		return NULL;

	return xbc_nodes;
}

/**
 * xbc_node_index() - Get the index of XBC node
 * @node: A target node of getting index.
 *
 * Return the index number of @node in XBC node list.
 */
int __init xbc_node_index(struct xbc_node *node)
{
	return node - &xbc_nodes[0];
}

/**
 * xbc_node_get_parent() - Get the parent XBC node
 * @node: An XBC node.
 *
 * Return the parent node of @node. If the node is top node of the tree,
 * return NULL.
 */
struct xbc_node * __init xbc_node_get_parent(struct xbc_node *node)
{
	return node->parent == XBC_NODE_MAX ? NULL : &xbc_nodes[node->parent];
}

/**
 * xbc_node_get_child() - Get the child XBC node
 * @node: An XBC node.
 *
 * Return the first child node of @node. If the node has no child, return
 * NULL.
 */
struct xbc_node * __init xbc_node_get_child(struct xbc_node *node)
{
	return node->child ? &xbc_nodes[node->child] : NULL;
}

/**
 * xbc_node_get_next() - Get the next sibling XBC node
 * @node: An XBC node.
 *
 * Return the NEXT sibling node of @node. If the node has no next sibling,
 * return NULL. Note that even if this returns NULL, it doesn't mean @node
 * has no siblings. (You also has to check whether the parent's child node
 * is @node or not.)
 */
struct xbc_node * __init xbc_node_get_next(struct xbc_node *node)
{
	return node->next ? &xbc_nodes[node->next] : NULL;
}

/**
 * xbc_node_get_data() - Get the data of XBC node
 * @node: An XBC node.
 *
 * Return the data (which is always a null terminated string) of @node.
 * If the node has invalid data, warn and return NULL.
 */
const char * __init xbc_node_get_data(struct xbc_node *node)
{
	int offset = node->data & ~XBC_VALUE;

	if (WARN_ON(offset >= xbc_data_size))
		return NULL;

	return xbc_data + offset;
}

static bool __init
xbc_node_match_prefix(struct xbc_node *node, const char **prefix)
{
	const char *p = xbc_node_get_data(node);
	int len = strlen(p);

	if (strncmp(*prefix, p, len))
		return false;

	p = *prefix + len;
	if (*p == '.')
		p++;
	else if (*p != '\0')
		return false;
	*prefix = p;

	return true;
}

/**
 * xbc_node_find_child() - Find a child node which matches given key
 * @parent: An XBC node.
 * @key: A key string.
 *
 * Search a node under @parent which matches @key. The @key can contain
 * several words jointed with '.'. If @parent is NULL, this searches the
 * node from whole tree. Return NULL if no node is matched.
 */
struct xbc_node * __init
xbc_node_find_child(struct xbc_node *parent, const char *key)
{
	struct xbc_node *node;

	if (parent)
		node = xbc_node_get_child(parent);
	else
		node = xbc_root_node();

	while (node && xbc_node_is_key(node)) {
		if (!xbc_node_match_prefix(node, &key))
			node = xbc_node_get_next(node);
		else if (*key != '\0')
			node = xbc_node_get_child(node);
		else
			break;
	}

	return node;
}

/**
 * xbc_node_find_value() - Find a value node which matches given key
 * @parent: An XBC node.
 * @key: A key string.
 * @vnode: A container pointer of found XBC node.
 *
 * Search a value node under @parent whose (parent) key node matches @key,
 * store it in *@vnode, and returns the value string.
 * The @key can contain several words jointed with '.'. If @parent is NULL,
 * this searches the node from whole tree. Return the value string if a
 * matched key found, return NULL if no node is matched.
 * Note that this returns 0-length string and stores NULL in *@vnode if the
 * key has no value. And also it will return the value of the first entry if
 * the value is an array.
 */
const char * __init
xbc_node_find_value(struct xbc_node *parent, const char *key,
		    struct xbc_node **vnode)
{
	struct xbc_node *node = xbc_node_find_child(parent, key);

	if (!node || !xbc_node_is_key(node))
		return NULL;

	node = xbc_node_get_child(node);
	if (node && !xbc_node_is_value(node))
		return NULL;

	if (vnode)
		*vnode = node;

	return node ? xbc_node_get_data(node) : "";
}

/**
 * xbc_node_compose_key_after() - Compose partial key string of the XBC node
 * @root: Root XBC node
 * @node: Target XBC node.
 * @buf: A buffer to store the key.
 * @size: The size of the @buf.
 *
 * Compose the partial key of the @node into @buf, which is starting right
 * after @root (@root is not included.) If @root is NULL, this returns full
 * key words of @node.
 * Returns the total length of the key stored in @buf. Returns -EINVAL
 * if @node is NULL or @root is not the ancestor of @node or @root is @node,
 * or returns -ERANGE if the key depth is deeper than max depth.
 * This is expected to be used with xbc_find_node() to list up all (child)
 * keys under given key.
 */
int __init xbc_node_compose_key_after(struct xbc_node *root,
				      struct xbc_node *node,
				      char *buf, size_t size)
{
	u16 keys[XBC_DEPTH_MAX];
	int depth = 0, ret = 0, total = 0;

	if (!node || node == root)
		return -EINVAL;

	if (xbc_node_is_value(node))
		node = xbc_node_get_parent(node);

	while (node && node != root) {
		keys[depth++] = xbc_node_index(node);
		if (depth == XBC_DEPTH_MAX)
			return -ERANGE;
		node = xbc_node_get_parent(node);
	}
	if (!node && root)
		return -EINVAL;

	while (--depth >= 0) {
		node = xbc_nodes + keys[depth];
		ret = snprintf(buf, size, "%s%s", xbc_node_get_data(node),
			       depth ? "." : "");
		if (ret < 0)
			return ret;
		if (ret > size) {
			size = 0;
		} else {
			size -= ret;
			buf += ret;
		}
		total += ret;
	}

	return total;
}

/**
 * xbc_node_find_next_leaf() - Find the next leaf node under given node
 * @root: An XBC root node
 * @node: An XBC node which starts from.
 *
 * Search the next leaf node (which means the terminal key node) of @node
 * under @root node (including @root node itself).
 * Return the next node or NULL if next leaf node is not found.
 */
struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root,
						 struct xbc_node *node)
{
	if (unlikely(!xbc_data))
		return NULL;

	if (!node) {	/* First try */
		node = root;
		if (!node)
			node = xbc_nodes;
	} else {
		if (node == root)	/* @root was a leaf, no child node. */
			return NULL;

		while (!node->next) {
			node = xbc_node_get_parent(node);
			if (node == root)
				return NULL;
			/* User passed a node which is not uder parent */
			if (WARN_ON(!node))
				return NULL;
		}
		node = xbc_node_get_next(node);
	}

	while (node && !xbc_node_is_leaf(node))
		node = xbc_node_get_child(node);

	return node;
}

/**
 * xbc_node_find_next_key_value() - Find the next key-value pair nodes
 * @root: An XBC root node
 * @leaf: A container pointer of XBC node which starts from.
 *
 * Search the next leaf node (which means the terminal key node) of *@leaf
 * under @root node. Returns the value and update *@leaf if next leaf node
 * is found, or NULL if no next leaf node is found.
 * Note that this returns 0-length string if the key has no value, or
 * the value of the first entry if the value is an array.
 */
const char * __init xbc_node_find_next_key_value(struct xbc_node *root,
						 struct xbc_node **leaf)
{
	/* tip must be passed */
	if (WARN_ON(!leaf))
		return NULL;

	*leaf = xbc_node_find_next_leaf(root, *leaf);
	if (!*leaf)
		return NULL;
	if ((*leaf)->child)
		return xbc_node_get_data(xbc_node_get_child(*leaf));
	else
		return "";	/* No value key */
}

/* XBC parse and tree build */

static struct xbc_node * __init xbc_add_node(char *data, u32 flag)
{
	struct xbc_node *node;
	unsigned long offset;

	if (xbc_node_num == XBC_NODE_MAX)
		return NULL;

	node = &xbc_nodes[xbc_node_num++];
	offset = data - xbc_data;
	node->data = (u16)offset;
	if (WARN_ON(offset >= XBC_DATA_MAX))
		return NULL;
	node->data |= flag;
	node->child = 0;
	node->next = 0;

	return node;
}

static inline __init struct xbc_node *xbc_last_sibling(struct xbc_node *node)
{
	while (node->next)
		node = xbc_node_get_next(node);

	return node;
}

static struct xbc_node * __init xbc_add_sibling(char *data, u32 flag)
{
	struct xbc_node *sib, *node = xbc_add_node(data, flag);

	if (node) {
		if (!last_parent) {
			node->parent = XBC_NODE_MAX;
			sib = xbc_last_sibling(xbc_nodes);
			sib->next = xbc_node_index(node);
		} else {
			node->parent = xbc_node_index(last_parent);
			if (!last_parent->child) {
				last_parent->child = xbc_node_index(node);
			} else {
				sib = xbc_node_get_child(last_parent);
				sib = xbc_last_sibling(sib);
				sib->next = xbc_node_index(node);
			}
		}
	} else
		xbc_parse_error("Too many nodes", data);

	return node;
}

static inline __init struct xbc_node *xbc_add_child(char *data, u32 flag)
{
	struct xbc_node *node = xbc_add_sibling(data, flag);

	if (node)
		last_parent = node;

	return node;
}

static inline __init bool xbc_valid_keyword(char *key)
{
	if (key[0] == '\0')
		return false;

	while (isalnum(*key) || *key == '-' || *key == '_')
		key++;

	return *key == '\0';
}

static char *skip_comment(char *p)
{
	char *ret;

	ret = strchr(p, '\n');
	if (!ret)
		ret = p + strlen(p);
	else
		ret++;

	return ret;
}

static char *skip_spaces_until_newline(char *p)
{
	while (isspace(*p) && *p != '\n')
		p++;
	return p;
}

static int __init __xbc_open_brace(void)
{
	/* Mark the last key as open brace */
	last_parent->next = XBC_NODE_MAX;

	return 0;
}

static int __init __xbc_close_brace(char *p)
{
	struct xbc_node *node;

	if (!last_parent || last_parent->next != XBC_NODE_MAX)
		return xbc_parse_error("Unexpected closing brace", p);

	node = last_parent;
	node->next = 0;
	do {
		node = xbc_node_get_parent(node);
	} while (node && node->next != XBC_NODE_MAX);
	last_parent = node;

	return 0;
}

/*
 * Return delimiter or error, no node added. As same as lib/cmdline.c,
 * you can use " around spaces, but can't escape " for value.
 */
static int __init __xbc_parse_value(char **__v, char **__n)
{
	char *p, *v = *__v;
	int c, quotes = 0;

	v = skip_spaces(v);
	while (*v == '#') {
		v = skip_comment(v);
		v = skip_spaces(v);
	}
	if (*v == '"' || *v == '\'') {
		quotes = *v;
		v++;
	}
	p = v - 1;
	while ((c = *++p)) {
		if (!isprint(c) && !isspace(c))
			return xbc_parse_error("Non printable value", p);
		if (quotes) {
			if (c != quotes)
				continue;
			quotes = 0;
			*p++ = '\0';
			p = skip_spaces_until_newline(p);
			c = *p;
			if (c && !strchr(",;\n#}", c))
				return xbc_parse_error("No value delimiter", p);
			if (*p)
				p++;
			break;
		}
		if (strchr(",;\n#}", c)) {
			v = strim(v);
			*p++ = '\0';
			break;
		}
	}
	if (quotes)
		return xbc_parse_error("No closing quotes", p);
	if (c == '#') {
		p = skip_comment(p);
		c = '\n';	/* A comment must be treated as a newline */
	}
	*__n = p;
	*__v = v;

	return c;
}

static int __init xbc_parse_array(char **__v)
{
	struct xbc_node *node;
	char *next;
	int c = 0;

	do {
		c = __xbc_parse_value(__v, &next);
		if (c < 0)
			return c;

		node = xbc_add_sibling(*__v, XBC_VALUE);
		if (!node)
			return -ENOMEM;
		*__v = next;
	} while (c == ',');
	node->next = 0;

	return c;
}

static inline __init
struct xbc_node *find_match_node(struct xbc_node *node, char *k)
{
	while (node) {
		if (!strcmp(xbc_node_get_data(node), k))
			break;
		node = xbc_node_get_next(node);
	}
	return node;
}

static int __init __xbc_add_key(char *k)
{
	struct xbc_node *node;

	if (!xbc_valid_keyword(k))
		return xbc_parse_error("Invalid keyword", k);

	if (unlikely(xbc_node_num == 0))
		goto add_node;

	if (!last_parent)	/* the first level */
		node = find_match_node(xbc_nodes, k);
	else
		node = find_match_node(xbc_node_get_child(last_parent), k);

	if (node)
		last_parent = node;
	else {
add_node:
		node = xbc_add_child(k, XBC_KEY);
		if (!node)
			return -ENOMEM;
	}
	return 0;
}

static int __init __xbc_parse_keys(char *k)
{
	char *p;
	int ret;

	k = strim(k);
	while ((p = strchr(k, '.'))) {
		*p++ = '\0';
		ret = __xbc_add_key(k);
		if (ret)
			return ret;
		k = p;
	}

	return __xbc_add_key(k);
}

static int __init xbc_parse_kv(char **k, char *v)
{
	struct xbc_node *prev_parent = last_parent;
	struct xbc_node *node;
	char *next;
	int c, ret;

	ret = __xbc_parse_keys(*k);
	if (ret)
		return ret;

	c = __xbc_parse_value(&v, &next);
	if (c < 0)
		return c;

	node = xbc_add_sibling(v, XBC_VALUE);
	if (!node)
		return -ENOMEM;

	if (c == ',') {	/* Array */
		c = xbc_parse_array(&next);
		if (c < 0)
			return c;
	}

	last_parent = prev_parent;

	if (c == '}') {
		ret = __xbc_close_brace(next - 1);
		if (ret < 0)
			return ret;
	}

	*k = next;

	return 0;
}

static int __init xbc_parse_key(char **k, char *n)
{
	struct xbc_node *prev_parent = last_parent;
	int ret;

	*k = strim(*k);
	if (**k != '\0') {
		ret = __xbc_parse_keys(*k);
		if (ret)
			return ret;
		last_parent = prev_parent;
	}
	*k = n;

	return 0;
}

static int __init xbc_open_brace(char **k, char *n)
{
	int ret;

	ret = __xbc_parse_keys(*k);
	if (ret)
		return ret;
	*k = n;

	return __xbc_open_brace();
}

static int __init xbc_close_brace(char **k, char *n)
{
	int ret;

	ret = xbc_parse_key(k, n);
	if (ret)
		return ret;
	/* k is updated in xbc_parse_key() */

	return __xbc_close_brace(n - 1);
}

static int __init xbc_verify_tree(void)
{
	int i, depth, len, wlen;
	struct xbc_node *n, *m;

	/* Empty tree */
	if (xbc_node_num == 0) {
		xbc_parse_error("Empty config", xbc_data);
		return -ENOENT;
	}

	for (i = 0; i < xbc_node_num; i++) {
		if (xbc_nodes[i].next > xbc_node_num) {
			return xbc_parse_error("No closing brace",
				xbc_node_get_data(xbc_nodes + i));
		}
	}

	/* Key tree limitation check */
	n = &xbc_nodes[0];
	depth = 1;
	len = 0;

	while (n) {
		wlen = strlen(xbc_node_get_data(n)) + 1;
		len += wlen;
		if (len > XBC_KEYLEN_MAX)
			return xbc_parse_error("Too long key length",
				xbc_node_get_data(n));

		m = xbc_node_get_child(n);
		if (m && xbc_node_is_key(m)) {
			n = m;
			depth++;
			if (depth > XBC_DEPTH_MAX)
				return xbc_parse_error("Too many key words",
						xbc_node_get_data(n));
			continue;
		}
		len -= wlen;
		m = xbc_node_get_next(n);
		while (!m) {
			n = xbc_node_get_parent(n);
			if (!n)
				break;
			len -= strlen(xbc_node_get_data(n)) + 1;
			depth--;
			m = xbc_node_get_next(n);
		}
		n = m;
	}

	return 0;
}

/**
 * xbc_destroy_all() - Clean up all parsed bootconfig
 *
 * This clears all data structures of parsed bootconfig on memory.
 * If you need to reuse xbc_init() with new boot config, you can
 * use this.
 */
void __init xbc_destroy_all(void)
{
	xbc_data = NULL;
	xbc_data_size = 0;
	xbc_node_num = 0;
	memset(xbc_nodes, 0, sizeof(xbc_nodes));
}

/**
 * xbc_init() - Parse given XBC file and build XBC internal tree
 * @buf: boot config text
 *
 * This parses the boot config text in @buf. @buf must be a
 * null terminated string and smaller than XBC_DATA_MAX.
 * Return the number of stored nodes (>0) if succeeded, or -errno
 * if there is any error.
 */
int __init xbc_init(char *buf)
{
	char *p, *q;
	int ret, c;

	if (xbc_data) {
		pr_err("Error: bootconfig is already initialized.\n");
		return -EBUSY;
	}

	ret = strlen(buf);
	if (ret > XBC_DATA_MAX - 1 || ret == 0) {
		pr_err("Error: Config data is %s.\n",
			ret ? "too big" : "empty");
		return -ERANGE;
	}

	xbc_data = buf;
	xbc_data_size = ret + 1;
	last_parent = NULL;

	p = buf;
	do {
		q = strpbrk(p, "{}=;\n#");
		if (!q) {
			p = skip_spaces(p);
			if (*p != '\0')
				ret = xbc_parse_error("No delimiter", p);
			break;
		}

		c = *q;
		*q++ = '\0';
		switch (c) {
		case '=':
			ret = xbc_parse_kv(&p, q);
			break;
		case '{':
			ret = xbc_open_brace(&p, q);
			break;
		case '#':
			q = skip_comment(q);
			/* fall through */
		case ';':
		case '\n':
			ret = xbc_parse_key(&p, q);
			break;
		case '}':
			ret = xbc_close_brace(&p, q);
			break;
		}
	} while (!ret);

	if (!ret)
		ret = xbc_verify_tree();

	if (ret < 0)
		xbc_destroy_all();
	else
		ret = xbc_node_num;

	return ret;
}

/**
 * xbc_debug_dump() - Dump current XBC node list
 *
 * Dump the current XBC node list on printk buffer for debug.
 */
void __init xbc_debug_dump(void)
{
	int i;

	for (i = 0; i < xbc_node_num; i++) {
		pr_debug("[%d] %s (%s) .next=%d, .child=%d .parent=%d\n", i,
			xbc_node_get_data(xbc_nodes + i),
			xbc_node_is_value(xbc_nodes + i) ? "value" : "key",
			xbc_nodes[i].next, xbc_nodes[i].child,
			xbc_nodes[i].parent);
	}
}