// SPDX-License-Identifier: GPL-2.0/* * Extra Boot Config * Masami Hiramatsu <mhiramat@kernel.org> */ #define pr_fmt(fmt)    "bootconfig: " fmt #include <linux/bootconfig.h>#include <linux/bug.h>#include <linux/ctype.h>#include <linux/errno.h>#include <linux/kernel.h>#include <linux/memblock.h>#include <linux/printk.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 __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 const char *xbc_err_msg __initdata;static int xbc_err_pos __initdata;static int open_brace[XBC_DEPTH_MAX] __initdata;static int brace_index __initdata; static int __init xbc_parse_error(const char *msg, const char *p){	xbc_err_msg = msg;	xbc_err_pos = (int)(p - xbc_data); 	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 __initxbc_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 * __initxbc_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 * __initxbc_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 int __init xbc_init_node(struct xbc_node *node, char *data, u32 flag){	unsigned long offset = data - xbc_data; 	if (WARN_ON(offset >= XBC_DATA_MAX))		return -EINVAL; 	node->data = (u16)offset | flag;	node->child = 0;	node->next = 0; 	return 0;} static struct xbc_node * __init xbc_add_node(char *data, u32 flag){	struct xbc_node *node; 	if (xbc_node_num == XBC_NODE_MAX)		return NULL; 	node = &xbc_nodes[xbc_node_num++];	if (xbc_init_node(node, data, flag) < 0)		return NULL; 	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(char *p){	/* Push the last key as open brace */	open_brace[brace_index++] = xbc_node_index(last_parent);	if (brace_index >= XBC_DEPTH_MAX)		return xbc_parse_error("Exceed max depth of braces", p); 	return 0;} static int __init __xbc_close_brace(char *p){	brace_index--;	if (!last_parent || brace_index < 0 ||	    (open_brace[brace_index] != xbc_node_index(last_parent)))		return xbc_parse_error("Unexpected closing brace", p); 	if (brace_index == 0)		last_parent = NULL;	else		last_parent = &xbc_nodes[open_brace[brace_index - 1]]; 	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)) {			*p++ = '\0';			v = strim(v);			break;		}

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