]>
git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - lib/bootconfig.c
1 // SPDX-License-Identifier: GPL-2.0
4 * Masami Hiramatsu <mhiramat@kernel.org>
7 #define pr_fmt(fmt) "bootconfig: " fmt
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>
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
27 static struct xbc_node
*xbc_nodes __initdata
;
28 static int xbc_node_num __initdata
;
29 static char *xbc_data __initdata
;
30 static size_t xbc_data_size __initdata
;
31 static struct xbc_node
*last_parent __initdata
;
32 static const char *xbc_err_msg __initdata
;
33 static int xbc_err_pos __initdata
;
34 static int open_brace
[XBC_DEPTH_MAX
] __initdata
;
35 static int brace_index __initdata
;
37 static int __init
xbc_parse_error(const char *msg
, const char *p
)
40 xbc_err_pos
= (int)(p
- xbc_data
);
46 * xbc_root_node() - Get the root node of extended boot config
48 * Return the address of root node of extended boot config. If the
49 * extended boot config is not initiized, return NULL.
51 struct xbc_node
* __init
xbc_root_node(void)
53 if (unlikely(!xbc_data
))
60 * xbc_node_index() - Get the index of XBC node
61 * @node: A target node of getting index.
63 * Return the index number of @node in XBC node list.
65 int __init
xbc_node_index(struct xbc_node
*node
)
67 return node
- &xbc_nodes
[0];
71 * xbc_node_get_parent() - Get the parent XBC node
74 * Return the parent node of @node. If the node is top node of the tree,
77 struct xbc_node
* __init
xbc_node_get_parent(struct xbc_node
*node
)
79 return node
->parent
== XBC_NODE_MAX
? NULL
: &xbc_nodes
[node
->parent
];
83 * xbc_node_get_child() - Get the child XBC node
86 * Return the first child node of @node. If the node has no child, return
89 struct xbc_node
* __init
xbc_node_get_child(struct xbc_node
*node
)
91 return node
->child
? &xbc_nodes
[node
->child
] : NULL
;
95 * xbc_node_get_next() - Get the next sibling XBC node
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
103 struct xbc_node
* __init
xbc_node_get_next(struct xbc_node
*node
)
105 return node
->next
? &xbc_nodes
[node
->next
] : NULL
;
109 * xbc_node_get_data() - Get the data of XBC node
110 * @node: An XBC node.
112 * Return the data (which is always a null terminated string) of @node.
113 * If the node has invalid data, warn and return NULL.
115 const char * __init
xbc_node_get_data(struct xbc_node
*node
)
117 int offset
= node
->data
& ~XBC_VALUE
;
119 if (WARN_ON(offset
>= xbc_data_size
))
122 return xbc_data
+ offset
;
126 xbc_node_match_prefix(struct xbc_node
*node
, const char **prefix
)
128 const char *p
= xbc_node_get_data(node
);
131 if (strncmp(*prefix
, p
, len
))
145 * xbc_node_find_subkey() - Find a subkey node which matches given key
146 * @parent: An XBC node.
147 * @key: A key string.
149 * Search a key 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.
153 struct xbc_node
* __init
154 xbc_node_find_subkey(struct xbc_node
*parent
, const char *key
)
156 struct xbc_node
*node
;
159 node
= xbc_node_get_subkey(parent
);
161 node
= xbc_root_node();
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_subkey(node
);
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.
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.
191 xbc_node_find_value(struct xbc_node
*parent
, const char *key
,
192 struct xbc_node
**vnode
)
194 struct xbc_node
*node
= xbc_node_find_subkey(parent
, key
);
196 if (!node
|| !xbc_node_is_key(node
))
199 node
= xbc_node_get_child(node
);
200 if (node
&& !xbc_node_is_value(node
))
206 return node
? xbc_node_get_data(node
) : "";
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.
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.
225 int __init
xbc_node_compose_key_after(struct xbc_node
*root
,
226 struct xbc_node
*node
,
227 char *buf
, size_t size
)
229 u16 keys
[XBC_DEPTH_MAX
];
230 int depth
= 0, ret
= 0, total
= 0;
232 if (!node
|| node
== root
)
235 if (xbc_node_is_value(node
))
236 node
= xbc_node_get_parent(node
);
238 while (node
&& node
!= root
) {
239 keys
[depth
++] = xbc_node_index(node
);
240 if (depth
== XBC_DEPTH_MAX
)
242 node
= xbc_node_get_parent(node
);
247 while (--depth
>= 0) {
248 node
= xbc_nodes
+ keys
[depth
];
249 ret
= snprintf(buf
, size
, "%s%s", xbc_node_get_data(node
),
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.
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.
274 struct xbc_node
* __init
xbc_node_find_next_leaf(struct xbc_node
*root
,
275 struct xbc_node
*node
)
277 struct xbc_node
*next
;
279 if (unlikely(!xbc_data
))
282 if (!node
) { /* First try */
287 /* Leaf node may have a subkey */
288 next
= xbc_node_get_subkey(node
);
294 if (node
== root
) /* @root was a leaf, no child node. */
297 while (!node
->next
) {
298 node
= xbc_node_get_parent(node
);
301 /* User passed a node which is not uder parent */
305 node
= xbc_node_get_next(node
);
309 while (node
&& !xbc_node_is_leaf(node
))
310 node
= xbc_node_get_child(node
);
316 * xbc_node_find_next_key_value() - Find the next key-value pair nodes
317 * @root: An XBC root node
318 * @leaf: A container pointer of XBC node which starts from.
320 * Search the next leaf node (which means the terminal key node) of *@leaf
321 * under @root node. Returns the value and update *@leaf if next leaf node
322 * is found, or NULL if no next leaf node is found.
323 * Note that this returns 0-length string if the key has no value, or
324 * the value of the first entry if the value is an array.
326 const char * __init
xbc_node_find_next_key_value(struct xbc_node
*root
,
327 struct xbc_node
**leaf
)
329 /* tip must be passed */
333 *leaf
= xbc_node_find_next_leaf(root
, *leaf
);
337 return xbc_node_get_data(xbc_node_get_child(*leaf
));
339 return ""; /* No value key */
342 /* XBC parse and tree build */
344 static int __init
xbc_init_node(struct xbc_node
*node
, char *data
, u32 flag
)
346 unsigned long offset
= data
- xbc_data
;
348 if (WARN_ON(offset
>= XBC_DATA_MAX
))
351 node
->data
= (u16
)offset
| flag
;
358 static struct xbc_node
* __init
xbc_add_node(char *data
, u32 flag
)
360 struct xbc_node
*node
;
362 if (xbc_node_num
== XBC_NODE_MAX
)
365 node
= &xbc_nodes
[xbc_node_num
++];
366 if (xbc_init_node(node
, data
, flag
) < 0)
372 static inline __init
struct xbc_node
*xbc_last_sibling(struct xbc_node
*node
)
375 node
= xbc_node_get_next(node
);
380 static inline __init
struct xbc_node
*xbc_last_child(struct xbc_node
*node
)
383 node
= xbc_node_get_child(node
);
388 static struct xbc_node
* __init
__xbc_add_sibling(char *data
, u32 flag
, bool head
)
390 struct xbc_node
*sib
, *node
= xbc_add_node(data
, flag
);
394 /* Ignore @head in this case */
395 node
->parent
= XBC_NODE_MAX
;
396 sib
= xbc_last_sibling(xbc_nodes
);
397 sib
->next
= xbc_node_index(node
);
399 node
->parent
= xbc_node_index(last_parent
);
400 if (!last_parent
->child
|| head
) {
401 node
->next
= last_parent
->child
;
402 last_parent
->child
= xbc_node_index(node
);
404 sib
= xbc_node_get_child(last_parent
);
405 sib
= xbc_last_sibling(sib
);
406 sib
->next
= xbc_node_index(node
);
410 xbc_parse_error("Too many nodes", data
);
415 static inline struct xbc_node
* __init
xbc_add_sibling(char *data
, u32 flag
)
417 return __xbc_add_sibling(data
, flag
, false);
420 static inline struct xbc_node
* __init
xbc_add_head_sibling(char *data
, u32 flag
)
422 return __xbc_add_sibling(data
, flag
, true);
425 static inline __init
struct xbc_node
*xbc_add_child(char *data
, u32 flag
)
427 struct xbc_node
*node
= xbc_add_sibling(data
, flag
);
435 static inline __init
bool xbc_valid_keyword(char *key
)
440 while (isalnum(*key
) || *key
== '-' || *key
== '_')
446 static char *skip_comment(char *p
)
450 ret
= strchr(p
, '\n');
459 static char *skip_spaces_until_newline(char *p
)
461 while (isspace(*p
) && *p
!= '\n')
466 static int __init
__xbc_open_brace(char *p
)
468 /* Push the last key as open brace */
469 open_brace
[brace_index
++] = xbc_node_index(last_parent
);
470 if (brace_index
>= XBC_DEPTH_MAX
)
471 return xbc_parse_error("Exceed max depth of braces", p
);
476 static int __init
__xbc_close_brace(char *p
)
479 if (!last_parent
|| brace_index
< 0 ||
480 (open_brace
[brace_index
] != xbc_node_index(last_parent
)))
481 return xbc_parse_error("Unexpected closing brace", p
);
483 if (brace_index
== 0)
486 last_parent
= &xbc_nodes
[open_brace
[brace_index
- 1]];
492 * Return delimiter or error, no node added. As same as lib/cmdline.c,
493 * you can use " around spaces, but can't escape " for value.
495 static int __init
__xbc_parse_value(char **__v
, char **__n
)
505 if (*v
== '"' || *v
== '\'') {
511 if (!isprint(c
) && !isspace(c
))
512 return xbc_parse_error("Non printable value", p
);
518 p
= skip_spaces_until_newline(p
);
520 if (c
&& !strchr(",;\n#}", c
))
521 return xbc_parse_error("No value delimiter", p
);
526 if (strchr(",;\n#}", c
)) {
533 return xbc_parse_error("No closing quotes", p
);
536 c
= '\n'; /* A comment must be treated as a newline */
544 static int __init
xbc_parse_array(char **__v
)
546 struct xbc_node
*node
;
550 if (last_parent
->child
)
551 last_parent
= xbc_node_get_child(last_parent
);
554 c
= __xbc_parse_value(__v
, &next
);
558 node
= xbc_add_child(*__v
, XBC_VALUE
);
569 struct xbc_node
*find_match_node(struct xbc_node
*node
, char *k
)
572 if (!strcmp(xbc_node_get_data(node
), k
))
574 node
= xbc_node_get_next(node
);
579 static int __init
__xbc_add_key(char *k
)
581 struct xbc_node
*node
, *child
;
583 if (!xbc_valid_keyword(k
))
584 return xbc_parse_error("Invalid keyword", k
);
586 if (unlikely(xbc_node_num
== 0))
589 if (!last_parent
) /* the first level */
590 node
= find_match_node(xbc_nodes
, k
);
592 child
= xbc_node_get_child(last_parent
);
593 /* Since the value node is the first child, skip it. */
594 if (child
&& xbc_node_is_value(child
))
595 child
= xbc_node_get_next(child
);
596 node
= find_match_node(child
, k
);
603 node
= xbc_add_child(k
, XBC_KEY
);
610 static int __init
__xbc_parse_keys(char *k
)
616 while ((p
= strchr(k
, '.'))) {
618 ret
= __xbc_add_key(k
);
624 return __xbc_add_key(k
);
627 static int __init
xbc_parse_kv(char **k
, char *v
, int op
)
629 struct xbc_node
*prev_parent
= last_parent
;
630 struct xbc_node
*child
;
634 ret
= __xbc_parse_keys(*k
);
638 c
= __xbc_parse_value(&v
, &next
);
642 child
= xbc_node_get_child(last_parent
);
643 if (child
&& xbc_node_is_value(child
)) {
645 return xbc_parse_error("Value is redefined", v
);
647 unsigned short nidx
= child
->next
;
649 xbc_init_node(child
, v
, XBC_VALUE
);
650 child
->next
= nidx
; /* keep subkeys */
654 last_parent
= xbc_last_child(child
);
656 /* The value node should always be the first child */
657 if (!xbc_add_head_sibling(v
, XBC_VALUE
))
661 if (c
== ',') { /* Array */
662 c
= xbc_parse_array(&next
);
667 last_parent
= prev_parent
;
670 ret
= __xbc_close_brace(next
- 1);
680 static int __init
xbc_parse_key(char **k
, char *n
)
682 struct xbc_node
*prev_parent
= last_parent
;
687 ret
= __xbc_parse_keys(*k
);
690 last_parent
= prev_parent
;
697 static int __init
xbc_open_brace(char **k
, char *n
)
701 ret
= __xbc_parse_keys(*k
);
706 return __xbc_open_brace(n
- 1);
709 static int __init
xbc_close_brace(char **k
, char *n
)
713 ret
= xbc_parse_key(k
, n
);
716 /* k is updated in xbc_parse_key() */
718 return __xbc_close_brace(n
- 1);
721 static int __init
xbc_verify_tree(void)
723 int i
, depth
, len
, wlen
;
724 struct xbc_node
*n
, *m
;
728 n
= &xbc_nodes
[open_brace
[brace_index
]];
729 return xbc_parse_error("Brace is not closed",
730 xbc_node_get_data(n
));
734 if (xbc_node_num
== 0) {
735 xbc_parse_error("Empty config", xbc_data
);
739 for (i
= 0; i
< xbc_node_num
; i
++) {
740 if (xbc_nodes
[i
].next
> xbc_node_num
) {
741 return xbc_parse_error("No closing brace",
742 xbc_node_get_data(xbc_nodes
+ i
));
746 /* Key tree limitation check */
752 wlen
= strlen(xbc_node_get_data(n
)) + 1;
754 if (len
> XBC_KEYLEN_MAX
)
755 return xbc_parse_error("Too long key length",
756 xbc_node_get_data(n
));
758 m
= xbc_node_get_child(n
);
759 if (m
&& xbc_node_is_key(m
)) {
762 if (depth
> XBC_DEPTH_MAX
)
763 return xbc_parse_error("Too many key words",
764 xbc_node_get_data(n
));
768 m
= xbc_node_get_next(n
);
770 n
= xbc_node_get_parent(n
);
773 len
-= strlen(xbc_node_get_data(n
)) + 1;
775 m
= xbc_node_get_next(n
);
784 * xbc_destroy_all() - Clean up all parsed bootconfig
786 * This clears all data structures of parsed bootconfig on memory.
787 * If you need to reuse xbc_init() with new boot config, you can
790 void __init
xbc_destroy_all(void)
795 memblock_free_ptr(xbc_nodes
, sizeof(struct xbc_node
) * XBC_NODE_MAX
);
801 * xbc_init() - Parse given XBC file and build XBC internal tree
802 * @buf: boot config text
803 * @emsg: A pointer of const char * to store the error message
804 * @epos: A pointer of int to store the error position
806 * This parses the boot config text in @buf. @buf must be a
807 * null terminated string and smaller than XBC_DATA_MAX.
808 * Return the number of stored nodes (>0) if succeeded, or -errno
809 * if there is any error.
810 * In error cases, @emsg will be updated with an error message and
811 * @epos will be updated with the error position which is the byte offset
812 * of @buf. If the error is not a parser error, @epos will be -1.
814 int __init
xbc_init(char *buf
, const char **emsg
, int *epos
)
824 *emsg
= "Bootconfig is already initialized";
829 if (ret
> XBC_DATA_MAX
- 1 || ret
== 0) {
831 *emsg
= ret
? "Config data is too big" :
832 "Config data is empty";
836 xbc_nodes
= memblock_alloc(sizeof(struct xbc_node
) * XBC_NODE_MAX
,
840 *emsg
= "Failed to allocate bootconfig nodes";
843 memset(xbc_nodes
, 0, sizeof(struct xbc_node
) * XBC_NODE_MAX
);
845 xbc_data_size
= ret
+ 1;
850 q
= strpbrk(p
, "{}=+;:\n#");
854 ret
= xbc_parse_error("No delimiter", p
);
864 ret
= xbc_parse_error(c
== '+' ?
865 "Wrong '+' operator" :
866 "Wrong ':' operator",
872 ret
= xbc_parse_kv(&p
, q
, c
);
875 ret
= xbc_open_brace(&p
, q
);
882 ret
= xbc_parse_key(&p
, q
);
885 ret
= xbc_close_brace(&p
, q
);
891 ret
= xbc_verify_tree();
906 * xbc_debug_dump() - Dump current XBC node list
908 * Dump the current XBC node list on printk buffer for debug.
910 void __init
xbc_debug_dump(void)
914 for (i
= 0; i
< xbc_node_num
; i
++) {
915 pr_debug("[%d] %s (%s) .next=%d, .child=%d .parent=%d\n", i
,
916 xbc_node_get_data(xbc_nodes
+ i
),
917 xbc_node_is_value(xbc_nodes
+ i
) ? "value" : "key",
918 xbc_nodes
[i
].next
, xbc_nodes
[i
].child
,
919 xbc_nodes
[i
].parent
);