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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Extra Boot Config
4 * Masami Hiramatsu <[email protected]>
5 */
6
7/*
8 * NOTE: This is only for tools/bootconfig, because tools/bootconfig will
9 * run the parser sanity test.
10 * This does NOT mean lib/bootconfig.c is available in the user space.
11 * However, if you change this file, please make sure the tools/bootconfig
12 * has no issue on building and running.
13 */
14#include <linux/bootconfig.h>
15
16#ifdef __KERNEL__
17#include <linux/bug.h>
18#include <linux/ctype.h>
19#include <linux/errno.h>
20#include <linux/cache.h>
21#include <linux/compiler.h>
22#include <linux/init.h>
23#include <linux/moduleparam.h>
24#include <linux/printk.h>
25#include <linux/sprintf.h>
26#include <linux/memblock.h>
27#include <linux/string.h>
28#include <asm/setup.h> /* COMMAND_LINE_SIZE */
29
30#ifdef CONFIG_BOOT_CONFIG_EMBED
31/* embedded_bootconfig_data is defined in bootconfig-data.S */
32extern __visible const char embedded_bootconfig_data[];
33extern __visible const char embedded_bootconfig_data_end[];
34
35const char * __init xbc_get_embedded_bootconfig(size_t *size)
36{
37 *size = embedded_bootconfig_data_end - embedded_bootconfig_data;
38 return (*size) ? embedded_bootconfig_data : NULL;
39}
40#endif
41
42#ifdef CONFIG_CMDLINE_FROM_BOOTCONFIG
43/* embedded_kernel_cmdline is defined in embedded-cmdline.S */
44extern __visible const char embedded_kernel_cmdline[];
45extern __visible const char embedded_kernel_cmdline_end[];
46
47/* Set once the embedded cmdline has actually been prepended. */
48static bool xbc_cmdline_applied __initdata;
49
50/*
51 * str_prepend() - Prepend @src in front of the string in @dst, in place
52 * @dst: NUL-terminated destination buffer, currently @dst_len bytes long
53 * @dst_len: length of the current @dst string (excluding its NUL)
54 * @src: bytes to prepend (not NUL-terminated)
55 * @src_len: number of bytes from @src to prepend
56 *
57 * The caller must guarantee @dst has room for src_len + dst_len + 1 bytes.
58 * Moving dst_len + 1 bytes carries @dst's NUL terminator too, so an empty
59 * @dst needs no special case.
60 */
61static void __init str_prepend(char *dst, size_t dst_len,
62 const char *src, size_t src_len)
63{
64 memmove(dst + src_len, dst, dst_len + 1);
65 memcpy(dst, src, src_len);
66}
67
68/**
69 * xbc_prepend_embedded_cmdline() - Prepend embedded bootconfig cmdline
70 * @dst: cmdline buffer to prepend into (must already contain a NUL byte)
71 * @size: total capacity of @dst in bytes
72 *
73 * Prepend the build-time-rendered "kernel" subtree of the embedded
74 * bootconfig to @dst. The rendered string already ends with a single
75 * space (the xbc_snprint_cmdline() invariant), which serves as the
76 * separator between the embedded keys and any existing content of @dst.
77 * On overflow, log an error and leave @dst untouched rather than
78 * silently truncating: booting without the embedded values is better
79 * than refusing to boot, and the error message tells the user why
80 * their embedded keys are missing.
81 *
82 * Intended to be called from setup_arch() before parse_early_param() so
83 * that early_param() handlers see the embedded values.
84 */
85void __init xbc_prepend_embedded_cmdline(char *dst, size_t size)
86{
87 size_t embed_len = embedded_kernel_cmdline_end - embedded_kernel_cmdline;
88 size_t dst_len;
89
90 if (!size || embed_len <= 1) /* trailing NUL only */
91 return;
92 embed_len--; /* exclude trailing NUL byte */
93
94 dst_len = strnlen(dst, size);
95 if (embed_len + dst_len + 1 > size) {
96 pr_err("embedded bootconfig cmdline (%zu bytes) does not fit in COMMAND_LINE_SIZE with %zu bytes already used; ignoring embedded values\n",
97 embed_len, dst_len);
98 return;
99 }
100
101 str_prepend(dst, dst_len, embedded_kernel_cmdline, embed_len);
102 xbc_cmdline_applied = true;
103}
104
105/**
106 * xbc_embedded_cmdline_applied() - Did the embedded cmdline get prepended?
107 *
108 * Return true if xbc_prepend_embedded_cmdline() actually prepended the
109 * embedded "kernel" subtree. setup_boot_config() uses this to avoid
110 * rendering the same keys a second time.
111 */
112bool __init xbc_embedded_cmdline_applied(void)
113{
114 return xbc_cmdline_applied;
115}
116#endif /* CONFIG_CMDLINE_FROM_BOOTCONFIG */
117
118/* parse_args() callback: flag when the "bootconfig" parameter is present. */
119static int __init bootconfig_optin(char *param, char *val,
120 const char *unused, void *arg)
121{
122 if (!strcmp(param, "bootconfig"))
123 *(bool *)arg = true;
124 return 0;
125}
126
127/**
128 * bootconfig_cmdline_requested() - Was "bootconfig" passed on the cmdline?
129 * @boot_cmdline: kernel command line to inspect (not modified)
130 * @end_offset: if non-NULL, set to the offset of the init arguments that
131 * follow a "--" separator, or 0 when there is none
132 *
133 * Parse a private copy of @boot_cmdline (parse_args() is destructive) and
134 * report whether "bootconfig" is present before the "--" separator.
135 * setup_arch() uses this to gate prepending the build-time embedded cmdline;
136 * setup_boot_config() uses it for the runtime opt-in and to locate the init
137 * arguments via @end_offset. Sharing one parser keeps the early and late
138 * paths agreeing on what counts as opt-in. CONFIG_BOOT_CONFIG_FORCE is not
139 * folded in here; callers apply it where they need it.
140 */
141bool __init bootconfig_cmdline_requested(const char *boot_cmdline, int *end_offset)
142{
143 static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
144 bool found = false;
145 char *err;
146
147 if (end_offset)
148 *end_offset = 0;
149
150 strscpy(tmp_cmdline, boot_cmdline, COMMAND_LINE_SIZE);
151 err = parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0,
152 &found, bootconfig_optin);
153 if (IS_ERR(err))
154 return false;
155
156 /* parse_args() stops at "--" and returns the address of the rest. */
157 if (end_offset && err)
158 *end_offset = err - tmp_cmdline;
159
160 return found;
161}
162
163#endif /* __KERNEL__ */
164
165/*
166 * Extra Boot Config (XBC) is given as tree-structured ascii text of
167 * key-value pairs on memory.
168 * xbc_parse() parses the text to build a simple tree. Each tree node is
169 * simply a key word or a value. A key node may have a next key node or/and
170 * a child node (both key and value). A value node may have a next value
171 * node (for array).
172 */
173
174static struct xbc_node *xbc_nodes __initdata;
175static int xbc_node_num __initdata;
176static char *xbc_data __initdata;
177static size_t xbc_data_size __initdata;
178static struct xbc_node *last_parent __initdata;
179static const char *xbc_err_msg __initdata;
180static int xbc_err_pos __initdata;
181static int open_brace[XBC_DEPTH_MAX] __initdata;
182static int brace_index __initdata;
183
184#ifdef __KERNEL__
185static inline void * __init xbc_alloc_mem(size_t size)
186{
187 return memblock_alloc(size, SMP_CACHE_BYTES);
188}
189
190static inline void __init xbc_free_mem(void *addr, size_t size, bool early)
191{
192 if (early)
193 memblock_free(addr, size);
194 else if (addr)
195 memblock_free(addr, size);
196}
197
198#else /* !__KERNEL__ */
199
200static inline void *xbc_alloc_mem(size_t size)
201{
202 return calloc(1, size);
203}
204
205static inline void xbc_free_mem(void *addr, size_t size, bool early)
206{
207 free(addr);
208}
209#endif
210
211/**
212 * xbc_get_info() - Get the information of loaded boot config
213 * @node_size: A pointer to store the number of nodes.
214 * @data_size: A pointer to store the size of bootconfig data.
215 *
216 * Get the number of used nodes in @node_size if it is not NULL,
217 * and the size of bootconfig data in @data_size if it is not NULL.
218 * Return 0 if the boot config is initialized, or return -ENODEV.
219 */
220int __init xbc_get_info(int *node_size, size_t *data_size)
221{
222 if (!xbc_data)
223 return -ENODEV;
224
225 if (node_size)
226 *node_size = xbc_node_num;
227 if (data_size)
228 *data_size = xbc_data_size;
229 return 0;
230}
231
232static int __init xbc_parse_error(const char *msg, const char *p)
233{
234 xbc_err_msg = msg;
235 xbc_err_pos = (int)(p - xbc_data);
236
237 return -EINVAL;
238}
239
240/**
241 * xbc_root_node() - Get the root node of extended boot config
242 *
243 * Return the address of root node of extended boot config. If the
244 * extended boot config is not initialized, return NULL.
245 */
246struct xbc_node * __init xbc_root_node(void)
247{
248 if (unlikely(!xbc_data))
249 return NULL;
250
251 return xbc_nodes;
252}
253
254/**
255 * xbc_node_index() - Get the index of XBC node
256 * @node: A target node of getting index.
257 *
258 * Return the index number of @node in XBC node list.
259 */
260uint16_t __init xbc_node_index(struct xbc_node *node)
261{
262 return (uint16_t)(node - &xbc_nodes[0]);
263}
264
265/**
266 * xbc_node_get_parent() - Get the parent XBC node
267 * @node: An XBC node.
268 *
269 * Return the parent node of @node. If the node is top node of the tree,
270 * return NULL.
271 */
272struct xbc_node * __init xbc_node_get_parent(struct xbc_node *node)
273{
274 return node->parent == XBC_NODE_MAX ? NULL : &xbc_nodes[node->parent];
275}
276
277/**
278 * xbc_node_get_child() - Get the child XBC node
279 * @node: An XBC node.
280 *
281 * Return the first child node of @node. If the node has no child, return
282 * NULL.
283 */
284struct xbc_node * __init xbc_node_get_child(struct xbc_node *node)
285{
286 return node->child ? &xbc_nodes[node->child] : NULL;
287}
288
289/**
290 * xbc_node_get_next() - Get the next sibling XBC node
291 * @node: An XBC node.
292 *
293 * Return the NEXT sibling node of @node. If the node has no next sibling,
294 * return NULL. Note that even if this returns NULL, it doesn't mean @node
295 * has no siblings. (You also has to check whether the parent's child node
296 * is @node or not.)
297 */
298struct xbc_node * __init xbc_node_get_next(struct xbc_node *node)
299{
300 return node->next ? &xbc_nodes[node->next] : NULL;
301}
302
303/**
304 * xbc_node_get_data() - Get the data of XBC node
305 * @node: An XBC node.
306 *
307 * Return the data (which is always a null terminated string) of @node.
308 * If the node has invalid data, warn and return NULL.
309 */
310const char * __init xbc_node_get_data(struct xbc_node *node)
311{
312 size_t offset = node->data & ~XBC_VALUE;
313
314 if (WARN_ON(offset >= xbc_data_size))
315 return NULL;
316
317 return xbc_data + offset;
318}
319
320static bool __init
321xbc_node_match_prefix(struct xbc_node *node, const char **prefix)
322{
323 const char *p = xbc_node_get_data(node);
324 size_t len = strlen(p);
325
326 if (strncmp(*prefix, p, len))
327 return false;
328
329 p = *prefix + len;
330 if (*p == '.')
331 p++;
332 else if (*p != '\0')
333 return false;
334 *prefix = p;
335
336 return true;
337}
338
339/**
340 * xbc_node_find_subkey() - Find a subkey node which matches given key
341 * @parent: An XBC node.
342 * @key: A key string.
343 *
344 * Search a key node under @parent which matches @key. The @key can contain
345 * several words jointed with '.'. If @parent is NULL, this searches the
346 * node from whole tree. Return NULL if no node is matched.
347 */
348struct xbc_node * __init
349xbc_node_find_subkey(struct xbc_node *parent, const char *key)
350{
351 struct xbc_node *node;
352
353 if (parent)
354 node = xbc_node_get_subkey(parent);
355 else
356 node = xbc_root_node();
357
358 while (node && xbc_node_is_key(node)) {
359 if (!xbc_node_match_prefix(node, &key))
360 node = xbc_node_get_next(node);
361 else if (*key != '\0')
362 node = xbc_node_get_subkey(node);
363 else
364 break;
365 }
366
367 return node;
368}
369
370/**
371 * xbc_node_find_value() - Find a value node which matches given key
372 * @parent: An XBC node.
373 * @key: A key string.
374 * @vnode: A container pointer of found XBC node.
375 *
376 * Search a value node under @parent whose (parent) key node matches @key,
377 * store it in *@vnode, and returns the value string.
378 * The @key can contain several words jointed with '.'. If @parent is NULL,
379 * this searches the node from whole tree. Return the value string if a
380 * matched key found, return NULL if no node is matched.
381 * Note that this returns 0-length string and stores NULL in *@vnode if the
382 * key has no value. And also it will return the value of the first entry if
383 * the value is an array.
384 */
385const char * __init
386xbc_node_find_value(struct xbc_node *parent, const char *key,
387 struct xbc_node **vnode)
388{
389 struct xbc_node *node = xbc_node_find_subkey(parent, key);
390
391 if (!node || !xbc_node_is_key(node))
392 return NULL;
393
394 node = xbc_node_get_child(node);
395 if (node && !xbc_node_is_value(node))
396 return NULL;
397
398 if (vnode)
399 *vnode = node;
400
401 return node ? xbc_node_get_data(node) : "";
402}
403
404/**
405 * xbc_node_compose_key_after() - Compose partial key string of the XBC node
406 * @root: Root XBC node
407 * @node: Target XBC node.
408 * @buf: A buffer to store the key.
409 * @size: The size of the @buf.
410 *
411 * Compose the partial key of the @node into @buf, which is starting right
412 * after @root (@root is not included.) If @root is NULL, this returns full
413 * key words of @node.
414 * Returns the total length of the key stored in @buf. Returns -EINVAL
415 * if @node is NULL or @root is not the ancestor of @node or @root is @node,
416 * or returns -ERANGE if the key depth is deeper than max depth.
417 * This is expected to be used with xbc_find_node() to list up all (child)
418 * keys under given key.
419 */
420int __init xbc_node_compose_key_after(struct xbc_node *root,
421 struct xbc_node *node,
422 char *buf, size_t size)
423{
424 uint16_t keys[XBC_DEPTH_MAX];
425 int depth = 0, ret = 0, total = 0;
426
427 if (!node || node == root)
428 return -EINVAL;
429
430 if (xbc_node_is_value(node))
431 node = xbc_node_get_parent(node);
432
433 while (node && node != root) {
434 keys[depth++] = xbc_node_index(node);
435 if (depth == XBC_DEPTH_MAX)
436 return -ERANGE;
437 node = xbc_node_get_parent(node);
438 }
439 if (!node && root)
440 return -EINVAL;
441
442 while (--depth >= 0) {
443 node = xbc_nodes + keys[depth];
444 ret = snprintf(buf, size, "%s%s", xbc_node_get_data(node),
445 depth ? "." : "");
446 if (ret < 0)
447 return ret;
448 if (ret >= size) {
449 size = 0;
450 } else {
451 size -= ret;
452 buf += ret;
453 }
454 total += ret;
455 }
456
457 return total;
458}
459
460/**
461 * xbc_node_find_next_leaf() - Find the next leaf node under given node
462 * @root: An XBC root node
463 * @node: An XBC node which starts from.
464 *
465 * Search the next leaf node (which means the terminal key node) of @node
466 * under @root node (including @root node itself).
467 * Return the next node or NULL if next leaf node is not found.
468 */
469struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root,
470 struct xbc_node *node)
471{
472 struct xbc_node *next;
473
474 if (unlikely(!xbc_data))
475 return NULL;
476
477 if (!node) { /* First try */
478 node = root;
479 if (!node)
480 node = xbc_nodes;
481 } else {
482 /* Leaf node may have a subkey */
483 next = xbc_node_get_subkey(node);
484 if (next) {
485 node = next;
486 goto found;
487 }
488
489 if (node == root) /* @root was a leaf, no child node. */
490 return NULL;
491
492 while (!node->next) {
493 node = xbc_node_get_parent(node);
494 if (node == root)
495 return NULL;
496 /* User passed a node which is not under parent */
497 if (WARN_ON(!node))
498 return NULL;
499 }
500 node = xbc_node_get_next(node);
501 }
502
503found:
504 while (node && !xbc_node_is_leaf(node))
505 node = xbc_node_get_child(node);
506
507 return node;
508}
509
510/**
511 * xbc_node_find_next_key_value() - Find the next key-value pair nodes
512 * @root: An XBC root node
513 * @leaf: A container pointer of XBC node which starts from.
514 *
515 * Search the next leaf node (which means the terminal key node) of *@leaf
516 * under @root node. Returns the value and update *@leaf if next leaf node
517 * is found, or NULL if no next leaf node is found.
518 * Note that this returns 0-length string if the key has no value, or
519 * the value of the first entry if the value is an array.
520 */
521const char * __init xbc_node_find_next_key_value(struct xbc_node *root,
522 struct xbc_node **leaf)
523{
524 /* tip must be passed */
525 if (WARN_ON(!leaf))
526 return NULL;
527
528 *leaf = xbc_node_find_next_leaf(root, *leaf);
529 if (!*leaf)
530 return NULL;
531 if ((*leaf)->child)
532 return xbc_node_get_data(xbc_node_get_child(*leaf));
533 else
534 return ""; /* No value key */
535}
536
537static char xbc_namebuf[XBC_KEYLEN_MAX] __initdata;
538
539#define rest(dst, end) ((end) > (dst) ? (end) - (dst) : 0)
540
541/**
542 * xbc_snprint_cmdline() - Render bootconfig keys under @root as a cmdline string
543 * @buf: Destination buffer (may be NULL when @size is 0 to query the length)
544 * @size: Size of @buf in bytes
545 * @root: Subtree root whose key=value pairs should be rendered
546 *
547 * Walk all key/value pairs under @root and emit them as a space-separated
548 * cmdline string into @buf. Values containing whitespace are quoted with
549 * double quotes. Returns the number of bytes that would be written if @buf
550 * were large enough (matching snprintf semantics), or a negative errno on
551 * failure.
552 */
553int __init xbc_snprint_cmdline(char *buf, size_t size, struct xbc_node *root)
554{
555 struct xbc_node *knode, *vnode;
556 const char *val, *q;
557 size_t len = 0;
558 int ret;
559
560 /*
561 * Track the running written length rather than advancing @buf, so we
562 * never form "buf + size" or "buf += ret" while @buf is NULL (the
563 * size-probe call passes buf=NULL, size=0). NULL pointer arithmetic
564 * is undefined behavior and trips host UBSan / FORTIFY_SOURCE when
565 * this renderer runs at kernel build time. snprintf(NULL, 0, ...)
566 * itself is well defined and returns the would-be length.
567 */
568 xbc_node_for_each_key_value(root, knode, val) {
569 /*
570 * An empty or value-only @root (e.g. "kernel {}" or
571 * "kernel = x", possibly alongside "kernel.foo = bar")
572 * yields @root itself here. Skip it: composing a key for it
573 * would fail with -EINVAL, yet any real descendant keys must
574 * still be rendered. An entirely empty subtree then renders
575 * nothing and returns 0 rather than an error.
576 */
577 if (knode == root)
578 continue;
579
580 ret = xbc_node_compose_key_after(root, knode,
581 xbc_namebuf, XBC_KEYLEN_MAX);
582 if (ret < 0)
583 return ret;
584
585 vnode = xbc_node_get_child(knode);
586 if (!vnode) {
587 ret = snprintf(buf ? buf + len : NULL, rest(len, size),
588 "%s ", xbc_namebuf);
589 if (ret < 0)
590 return ret;
591 len += ret;
592 continue;
593 }
594 xbc_array_for_each_value(vnode, val) {
595 /*
596 * For prettier and more readable /proc/cmdline, only
597 * quote the value when necessary, i.e. when it contains
598 * whitespace.
599 */
600 q = strpbrk(val, " \t\r\n") ? "\"" : "";
601 ret = snprintf(buf ? buf + len : NULL, rest(len, size),
602 "%s=%s%s%s ", xbc_namebuf, q, val, q);
603 if (ret < 0)
604 return ret;
605 len += ret;
606 }
607 }
608
609 return len;
610}
611#undef rest
612
613/* XBC parse and tree build */
614
615static int __init xbc_init_node(struct xbc_node *node, char *data, uint16_t flag)
616{
617 long offset = data - xbc_data;
618
619 if (WARN_ON(offset < 0 || offset >= XBC_DATA_MAX))
620 return -EINVAL;
621
622 node->data = (uint16_t)offset | flag;
623 node->child = 0;
624 node->next = 0;
625
626 return 0;
627}
628
629static struct xbc_node * __init xbc_add_node(char *data, uint16_t flag)
630{
631 struct xbc_node *node;
632
633 if (xbc_node_num == XBC_NODE_MAX)
634 return NULL;
635
636 node = &xbc_nodes[xbc_node_num];
637 if (xbc_init_node(node, data, flag) < 0)
638 return NULL;
639 xbc_node_num++;
640
641 return node;
642}
643
644static inline __init struct xbc_node *xbc_last_sibling(struct xbc_node *node)
645{
646 while (node->next)
647 node = xbc_node_get_next(node);
648
649 return node;
650}
651
652static inline __init struct xbc_node *xbc_last_child(struct xbc_node *node)
653{
654 while (node->child)
655 node = xbc_node_get_child(node);
656
657 return node;
658}
659
660static struct xbc_node * __init __xbc_add_sibling(char *data, uint16_t flag, bool head)
661{
662 struct xbc_node *sib, *node = xbc_add_node(data, flag);
663
664 if (node) {
665 if (!last_parent) {
666 /* Ignore @head in this case */
667 node->parent = XBC_NODE_MAX;
668 sib = xbc_last_sibling(xbc_nodes);
669 sib->next = xbc_node_index(node);
670 } else {
671 node->parent = xbc_node_index(last_parent);
672 if (!last_parent->child || head) {
673 node->next = last_parent->child;
674 last_parent->child = xbc_node_index(node);
675 } else {
676 sib = xbc_node_get_child(last_parent);
677 sib = xbc_last_sibling(sib);
678 sib->next = xbc_node_index(node);
679 }
680 }
681 } else {
682 xbc_parse_error("Too many nodes", data);
683 }
684
685 return node;
686}
687
688static inline struct xbc_node * __init xbc_add_sibling(char *data, uint16_t flag)
689{
690 return __xbc_add_sibling(data, flag, false);
691}
692
693static inline struct xbc_node * __init xbc_add_head_sibling(char *data, uint16_t flag)
694{
695 return __xbc_add_sibling(data, flag, true);
696}
697
698static inline __init struct xbc_node *xbc_add_child(char *data, uint16_t flag)
699{
700 struct xbc_node *node = xbc_add_sibling(data, flag);
701
702 if (node)
703 last_parent = node;
704
705 return node;
706}
707
708static inline __init bool xbc_valid_keyword(char *key)
709{
710 if (key[0] == '\0')
711 return false;
712
713 while (isalnum(*key) || *key == '-' || *key == '_')
714 key++;
715
716 return *key == '\0';
717}
718
719static char *skip_comment(char *p)
720{
721 char *ret;
722
723 ret = strchr(p, '\n');
724 if (!ret)
725 ret = p + strlen(p);
726 else
727 ret++;
728
729 return ret;
730}
731
732static char *skip_spaces_until_newline(char *p)
733{
734 while (isspace(*p) && *p != '\n')
735 p++;
736 return p;
737}
738
739static int __init __xbc_open_brace(char *p)
740{
741 /* Push the last key as open brace */
742 if (brace_index >= XBC_DEPTH_MAX)
743 return xbc_parse_error("Exceed max depth of braces", p);
744 open_brace[brace_index++] = xbc_node_index(last_parent);
745
746 return 0;
747}
748
749static int __init __xbc_close_brace(char *p)
750{
751 brace_index--;
752 if (!last_parent || brace_index < 0 ||
753 (open_brace[brace_index] != xbc_node_index(last_parent)))
754 return xbc_parse_error("Unexpected closing brace", p);
755
756 if (brace_index == 0)
757 last_parent = NULL;
758 else
759 last_parent = &xbc_nodes[open_brace[brace_index - 1]];
760
761 return 0;
762}
763
764/*
765 * Return delimiter or error, no node added. As same as lib/cmdline.c,
766 * you can use " around spaces, but can't escape " for value.
767 * *@__v must point real value string. (not including spaces before value.)
768 */
769static int __init __xbc_parse_value(char **__v, char **__n)
770{
771 char *p, *v = *__v;
772 int c, quotes = 0;
773
774 if (*v == '"' || *v == '\'') {
775 quotes = *v;
776 v++;
777 }
778 p = v - 1;
779 while ((c = *++p)) {
780 if (!isprint(c) && !isspace(c))
781 return xbc_parse_error("Non printable value", p);
782 if (quotes) {
783 if (c != quotes)
784 continue;
785 quotes = 0;
786 *p++ = '\0';
787 p = skip_spaces_until_newline(p);
788 c = *p;
789 if (c && !strchr(",;\n#}", c))
790 return xbc_parse_error("No value delimiter", p);
791 if (*p)
792 p++;
793 break;
794 }
795 if (strchr(",;\n#}", c)) {
796 *p++ = '\0';
797 v = strim(v);
798 break;
799 }
800 }
801 if (quotes)
802 return xbc_parse_error("No closing quotes", p);
803 if (c == '#') {
804 p = skip_comment(p);
805 c = '\n'; /* A comment must be treated as a newline */
806 }
807 *__n = p;
808 *__v = v;
809
810 return c;
811}
812
813static int __init xbc_parse_array(char **__v)
814{
815 struct xbc_node *node;
816 char *next;
817 int c = 0;
818
819 if (last_parent->child)
820 last_parent = xbc_node_get_child(last_parent);
821
822 do {
823 /* Search the next array value beyond comments and empty lines */
824 next = skip_spaces(*__v);
825 while (*next == '#') {
826 next = skip_comment(next);
827 next = skip_spaces(next);
828 }
829 *__v = next;
830 c = __xbc_parse_value(__v, &next);
831 if (c < 0)
832 return c;
833
834 node = xbc_add_child(*__v, XBC_VALUE);
835 if (!node)
836 return -ENOMEM;
837 *__v = next;
838 } while (c == ',');
839 node->child = 0;
840
841 return c;
842}
843
844static inline __init
845struct xbc_node *find_match_node(struct xbc_node *node, char *k)
846{
847 while (node) {
848 if (!strcmp(xbc_node_get_data(node), k))
849 break;
850 node = xbc_node_get_next(node);
851 }
852 return node;
853}
854
855static int __init __xbc_add_key(char *k)
856{
857 struct xbc_node *node, *child;
858
859 if (!xbc_valid_keyword(k))
860 return xbc_parse_error("Invalid keyword", k);
861
862 if (unlikely(xbc_node_num == 0))
863 goto add_node;
864
865 if (!last_parent) { /* the first level */
866 node = find_match_node(xbc_nodes, k);
867 } else {
868 child = xbc_node_get_child(last_parent);
869 /* Since the value node is the first child, skip it. */
870 if (child && xbc_node_is_value(child))
871 child = xbc_node_get_next(child);
872 node = find_match_node(child, k);
873 }
874
875 if (node) {
876 last_parent = node;
877 } else {
878add_node:
879 node = xbc_add_child(k, XBC_KEY);
880 if (!node)
881 return -ENOMEM;
882 }
883 return 0;
884}
885
886static int __init __xbc_parse_keys(char *k)
887{
888 char *p;
889 int ret;
890
891 k = strim(k);
892 while ((p = strchr(k, '.'))) {
893 *p++ = '\0';
894 ret = __xbc_add_key(k);
895 if (ret)
896 return ret;
897 k = p;
898 }
899
900 return __xbc_add_key(k);
901}
902
903static int __init xbc_parse_kv(char **k, char *v, int op)
904{
905 struct xbc_node *prev_parent = last_parent;
906 struct xbc_node *child;
907 char *next;
908 int c, ret;
909
910 ret = __xbc_parse_keys(*k);
911 if (ret)
912 return ret;
913
914 v = skip_spaces_until_newline(v);
915 /* If there is a comment, this has an empty value. */
916 if (*v == '#') {
917 next = skip_comment(v);
918 *v = '\0';
919 c = '\n';
920 } else {
921 c = __xbc_parse_value(&v, &next);
922 if (c < 0)
923 return c;
924 }
925
926 child = xbc_node_get_child(last_parent);
927 if (child && xbc_node_is_value(child)) {
928 if (op == '=')
929 return xbc_parse_error("Value is redefined", v);
930 if (op == ':') {
931 unsigned short nidx = child->next;
932
933 if (xbc_init_node(child, v, XBC_VALUE) < 0)
934 return xbc_parse_error("Failed to override value", v);
935 child->next = nidx; /* keep subkeys */
936 goto array;
937 }
938 /* op must be '+' */
939 last_parent = xbc_last_child(child);
940 }
941 /* The value node should always be the first child */
942 if (!xbc_add_head_sibling(v, XBC_VALUE))
943 return -ENOMEM;
944
945array:
946 if (c == ',') { /* Array */
947 c = xbc_parse_array(&next);
948 if (c < 0)
949 return c;
950 }
951
952 last_parent = prev_parent;
953
954 if (c == '}') {
955 ret = __xbc_close_brace(next - 1);
956 if (ret < 0)
957 return ret;
958 }
959
960 *k = next;
961
962 return 0;
963}
964
965static int __init xbc_parse_key(char **k, char *n)
966{
967 struct xbc_node *prev_parent = last_parent;
968 int ret;
969
970 *k = strim(*k);
971 if (**k != '\0') {
972 ret = __xbc_parse_keys(*k);
973 if (ret)
974 return ret;
975 last_parent = prev_parent;
976 }
977 *k = n;
978
979 return 0;
980}
981
982static int __init xbc_open_brace(char **k, char *n)
983{
984 int ret;
985
986 ret = __xbc_parse_keys(*k);
987 if (ret)
988 return ret;
989 *k = n;
990
991 return __xbc_open_brace(n - 1);
992}
993
994static int __init xbc_close_brace(char **k, char *n)
995{
996 int ret;
997
998 ret = xbc_parse_key(k, n);
999 if (ret)
1000 return ret;
1001 /* k is updated in xbc_parse_key() */
1002
1003 return __xbc_close_brace(n - 1);
1004}
1005
1006static int __init xbc_verify_tree(void)
1007{
1008 int i, depth;
1009 size_t len, wlen;
1010 struct xbc_node *n, *m;
1011
1012 /* Brace closing */
1013 if (brace_index) {
1014 n = &xbc_nodes[open_brace[brace_index - 1]];
1015 return xbc_parse_error("Brace is not closed",
1016 xbc_node_get_data(n));
1017 }
1018
1019 /* Empty tree */
1020 if (xbc_node_num == 0) {
1021 xbc_parse_error("Empty config", xbc_data);
1022 return -ENOENT;
1023 }
1024
1025 for (i = 0; i < xbc_node_num; i++) {
1026 if (xbc_nodes[i].next >= xbc_node_num) {
1027 return xbc_parse_error("No closing brace",
1028 xbc_node_get_data(xbc_nodes + i));
1029 }
1030 if (xbc_nodes[i].child >= xbc_node_num) {
1031 return xbc_parse_error("Broken child node",
1032 xbc_node_get_data(xbc_nodes + i));
1033 }
1034 }
1035
1036 /* Key tree limitation check */
1037 n = &xbc_nodes[0];
1038 depth = 1;
1039 len = 0;
1040
1041 while (n) {
1042 wlen = strlen(xbc_node_get_data(n)) + 1;
1043 len += wlen;
1044 if (len > XBC_KEYLEN_MAX)
1045 return xbc_parse_error("Too long key length",
1046 xbc_node_get_data(n));
1047
1048 m = xbc_node_get_child(n);
1049 if (m && xbc_node_is_key(m)) {
1050 n = m;
1051 depth++;
1052 if (depth > XBC_DEPTH_MAX)
1053 return xbc_parse_error("Too many key words",
1054 xbc_node_get_data(n));
1055 continue;
1056 }
1057 len -= wlen;
1058 m = xbc_node_get_next(n);
1059 while (!m) {
1060 n = xbc_node_get_parent(n);
1061 if (!n)
1062 break;
1063 len -= strlen(xbc_node_get_data(n)) + 1;
1064 depth--;
1065 m = xbc_node_get_next(n);
1066 }
1067 n = m;
1068 }
1069
1070 return 0;
1071}
1072
1073/* Need to setup xbc_data and xbc_nodes before call this. */
1074static int __init xbc_parse_tree(void)
1075{
1076 char *p, *q;
1077 int ret = 0, c;
1078
1079 last_parent = NULL;
1080 p = xbc_data;
1081 do {
1082 q = strpbrk(p, "{}=+;:\n#");
1083 if (!q) {
1084 p = skip_spaces(p);
1085 if (*p != '\0')
1086 ret = xbc_parse_error("No delimiter", p);
1087 break;
1088 }
1089
1090 c = *q;
1091 *q++ = '\0';
1092 switch (c) {
1093 case ':':
1094 case '+':
1095 if (*q++ != '=') {
1096 ret = xbc_parse_error(c == '+' ?
1097 "Wrong '+' operator" :
1098 "Wrong ':' operator",
1099 q - 2);
1100 break;
1101 }
1102 fallthrough;
1103 case '=':
1104 ret = xbc_parse_kv(&p, q, c);
1105 break;
1106 case '{':
1107 ret = xbc_open_brace(&p, q);
1108 break;
1109 case '#':
1110 q = skip_comment(q);
1111 fallthrough;
1112 case ';':
1113 case '\n':
1114 ret = xbc_parse_key(&p, q);
1115 break;
1116 case '}':
1117 ret = xbc_close_brace(&p, q);
1118 break;
1119 }
1120 } while (!ret);
1121
1122 return ret;
1123}
1124
1125/**
1126 * _xbc_exit() - Clean up all parsed bootconfig
1127 * @early: Set true if this is called before budy system is initialized.
1128 *
1129 * This clears all data structures of parsed bootconfig on memory.
1130 * If you need to reuse xbc_init() with new boot config, you can
1131 * use this.
1132 */
1133void __init _xbc_exit(bool early)
1134{
1135 xbc_free_mem(xbc_data, xbc_data_size, early);
1136 xbc_data = NULL;
1137 xbc_data_size = 0;
1138 xbc_node_num = 0;
1139 xbc_free_mem(xbc_nodes, sizeof(struct xbc_node) * XBC_NODE_MAX, early);
1140 xbc_nodes = NULL;
1141 brace_index = 0;
1142}
1143
1144/**
1145 * xbc_init() - Parse given XBC file and build XBC internal tree
1146 * @data: The boot config text original data
1147 * @size: The size of @data
1148 * @emsg: A pointer of const char * to store the error message
1149 * @epos: A pointer of int to store the error position
1150 *
1151 * This parses the boot config text in @data. @size must be smaller
1152 * than XBC_DATA_MAX.
1153 * Return the number of stored nodes (>0) if succeeded, or -errno
1154 * if there is any error.
1155 * In error cases, @emsg will be updated with an error message and
1156 * @epos will be updated with the error position which is the byte offset
1157 * of @buf. If the error is not a parser error, @epos will be -1.
1158 */
1159int __init xbc_init(const char *data, size_t size, const char **emsg, int *epos)
1160{
1161 int ret;
1162
1163 if (epos)
1164 *epos = -1;
1165
1166 if (xbc_data) {
1167 if (emsg)
1168 *emsg = "Bootconfig is already initialized";
1169 return -EBUSY;
1170 }
1171 if (size > XBC_DATA_MAX || size == 0) {
1172 if (emsg)
1173 *emsg = size ? "Config data is too big" :
1174 "Config data is empty";
1175 return -ERANGE;
1176 }
1177
1178 xbc_data = xbc_alloc_mem(size + 1);
1179 if (!xbc_data) {
1180 if (emsg)
1181 *emsg = "Failed to allocate bootconfig data";
1182 return -ENOMEM;
1183 }
1184 memcpy(xbc_data, data, size);
1185 xbc_data[size] = '\0';
1186 xbc_data_size = size + 1;
1187
1188 xbc_nodes = xbc_alloc_mem(sizeof(struct xbc_node) * XBC_NODE_MAX);
1189 if (!xbc_nodes) {
1190 if (emsg)
1191 *emsg = "Failed to allocate bootconfig nodes";
1192 _xbc_exit(true);
1193 return -ENOMEM;
1194 }
1195
1196 ret = xbc_parse_tree();
1197 if (!ret)
1198 ret = xbc_verify_tree();
1199
1200 if (ret < 0) {
1201 if (epos)
1202 *epos = xbc_err_pos;
1203 if (emsg)
1204 *emsg = xbc_err_msg;
1205 _xbc_exit(true);
1206 } else {
1207 ret = xbc_node_num;
1208 }
1209
1210 return ret;
1211}