[PATCH v6 01/22] bootconfig: Add Extra Boot Config support

Masami Hiramatsu
2020-01-10T16:03:42Z

Extra Boot Config (XBC) allows admin to pass a tree-structured
boot configuration file when boot up the kernel. This extends
the kernel command line in an efficient way.

Boot config will contain some key-value commands, e.g.

key.word = value1
another.key.word = value2

It can fold same keys with braces, also you can write array
data. For example,

key {
word1 {
setting1 = data
setting2
}
word2.array = "val1", "val2"
}

User can access these key-value pair and tree structure via
SKC APIs.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
Changes in v6:
- Remove "!!" from xbc_node_is_value().
- Redefine xbc_node_is_key() as "!xbc_node_is_value()".
- Fix a memory leak and a bug in __xbc_parse_value() (Thanks Steve!).
- Add xbc_destroy_all() to clean up the parsed data.
- Fix to treat comment right after value as a newline.
Changes in v5:
- Fix help comment and indent (Thanks Randy!)
- Restrict available characters in values (only printables and spaces.)
- Drop "escape" backslash support.
Changes in v4:
- Rename suppremental kernel command line to extended boot.
config so that easy to understand what it is.
- Clean up given data if failed to parse it.
- Add comment support (start with #)
- Return -ENOENT if given data has no node.
- Ensure the key max depth and keylen are under limitation.
- Add single quotes support.
- Allow newline and closing brace to terminate key-value.
- Add xbc_node_compose_key_after().
- Move kconfig to generic setup.
- Expand the max number of node to 1024.
---
MAINTAINERS | 6
include/linux/bootconfig.h | 224 ++++++++++++
init/Kconfig | 11 +
lib/Kconfig | 3
lib/Makefile | 2
lib/bootconfig.c | 803 ++++++++++++++++++++++++++++++++++++++++++++
6 files changed, 1049 insertions(+)
create mode 100644 include/linux/bootconfig.h
create mode 100644 lib/bootconfig.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 8982c6e013b3..1ef065234cff 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15773,6 +15773,12 @@ W: http://www.stlinux.com
S: Supported
F: drivers/net/ethernet/stmicro/stmmac/

+EXTRA BOOT CONFIG
+M: Masami Hiramatsu <mhiramat@kernel.org>
+S: Maintained
+F: lib/bootconfig.c
+F: include/linux/bootconfig.h
+
SUN3/3X
M: Sam Creasey <sammy@sammy.net>
W: http://sammy.net/sun3/
diff --git a/include/linux/bootconfig.h b/include/linux/bootconfig.h
new file mode 100644
index 000000000000..7e18c939663e
--- /dev/null
+++ b/include/linux/bootconfig.h
@@ -0,0 +1,224 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_XBC_H
+#define _LINUX_XBC_H
+/*
+ * Extra Boot Config
+ * Copyright (C) 2019 Linaro Ltd.
+ * Author: Masami Hiramatsu <mhiramat@kernel.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+
+/* XBC tree node */
+struct xbc_node {
+ u16 next;
+ u16 child;
+ u16 parent;
+ u16 data;
+} __attribute__ ((__packed__));
+
+#define XBC_KEY 0
+#define XBC_VALUE (1 << 15)
+/* Maximum size of boot config is 32KB - 1 */
+#define XBC_DATA_MAX (XBC_VALUE - 1)
+
+#define XBC_NODE_MAX 1024
+#define XBC_KEYLEN_MAX 256
+#define XBC_DEPTH_MAX 16
+
+/* Node tree access raw APIs */
+struct xbc_node * __init xbc_root_node(void);
+int __init xbc_node_index(struct xbc_node *node);
+struct xbc_node * __init xbc_node_get_parent(struct xbc_node *node);
+struct xbc_node * __init xbc_node_get_child(struct xbc_node *node);
+struct xbc_node * __init xbc_node_get_next(struct xbc_node *node);
+const char * __init xbc_node_get_data(struct xbc_node *node);
+
+/**
+ * xbc_node_is_value() - Test the node is a value node
+ * @node: An XBC node.
+ *
+ * Test the @node is a value node and return true if a value node, false if not.
+ */
+static inline __init bool xbc_node_is_value(struct xbc_node *node)
+{
+ return node->data & XBC_VALUE;
+}
+
+/**
+ * xbc_node_is_key() - Test the node is a key node
+ * @node: An XBC node.
+ *
+ * Test the @node is a key node and return true if a key node, false if not.
+ */
+static inline __init bool xbc_node_is_key(struct xbc_node *node)
+{
+ return !xbc_node_is_value(node);
+}
+
+/**
+ * xbc_node_is_array() - Test the node is an arraied value node
+ * @node: An XBC node.
+ *
+ * Test the @node is an arraied value node.
+ */
+static inline __init bool xbc_node_is_array(struct xbc_node *node)
+{
+ return xbc_node_is_value(node) && node->next != 0;
+}
+
+/**
+ * xbc_node_is_leaf() - Test the node is a leaf key node
+ * @node: An XBC node.
+ *
+ * Test the @node is a leaf key node which is a key node and has a value node
+ * or no child. Returns true if it is a leaf node, or false if not.
+ */
+static inline __init bool xbc_node_is_leaf(struct xbc_node *node)
+{
+ return xbc_node_is_key(node) &&
+ (!node->child || xbc_node_is_value(xbc_node_get_child(node)));
+}
+
+/* Tree-based key-value access APIs */
+struct xbc_node * __init xbc_node_find_child(struct xbc_node *parent,
+ const char *key);
+
+const char * __init xbc_node_find_value(struct xbc_node *parent,
+ const char *key,
+ struct xbc_node **vnode);
+
+struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root,
+ struct xbc_node *leaf);
+
+const char * __init xbc_node_find_next_key_value(struct xbc_node *root,
+ struct xbc_node **leaf);
+
+/**
+ * xbc_find_value() - Find a value which matches the key
+ * @key: Search key
+ * @vnode: A container pointer of XBC value node.
+ *
+ * Search a value whose key matches @key from whole of XBC tree and return
+ * the value if found. Found value node is stored in *@vnode.
+ * Note that this can return 0-length string and store NULL in *@vnode for
+ * key-only (non-value) entry.
+ */
+static inline const char * __init
+xbc_find_value(const char *key, struct xbc_node **vnode)
+{
+ return xbc_node_find_value(NULL, key, vnode);
+}
+
+/**
+ * xbc_find_node() - Find a node which matches the key
+ * @key: Search key
+ *
+ * Search a (key) node whose key matches @key from whole of XBC tree and
+ * return the node if found. If not found, returns NULL.
+ */
+static inline struct xbc_node * __init xbc_find_node(const char *key)
+{
+ return xbc_node_find_child(NULL, key);
+}
+
+/**
+ * xbc_array_for_each_value() - Iterate value nodes on an array
+ * @anode: An XBC arraied value node
+ * @value: A value
+ *
+ * Iterate array value nodes and values starts from @anode. This is expected to
+ * be used with xbc_find_value() and xbc_node_find_value(), so that user can
+ * process each array entry node.
+ */
+#define xbc_array_for_each_value(anode, value) \
+ for (value = xbc_node_get_data(anode); anode != NULL ; \
+ anode = xbc_node_get_next(anode), \
+ value = anode ? xbc_node_get_data(anode) : NULL)
+
+/**
+ * xbc_node_for_each_child() - Iterate child nodes
+ * @parent: An XBC node.
+ * @child: Iterated XBC node.
+ *
+ * Iterate child nodes of @parent. Each child nodes are stored to @child.
+ */
+#define xbc_node_for_each_child(parent, child) \
+ for (child = xbc_node_get_child(parent); child != NULL ; \
+ child = xbc_node_get_next(child))
+
+/**
+ * xbc_node_for_each_array_value() - Iterate array entries of geven key
+ * @node: An XBC node.
+ * @key: A key string searched under @node
+ * @anode: Iterated XBC node of array entry.
+ * @value: Iterated value of array entry.
+ *
+ * Iterate array entries of given @key under @node. Each array entry node
+ * is stroed to @anode and @value. If the @node doesn't have @key node,
+ * it does nothing.
+ * Note that even if the found key node has only one value (not array)
+ * this executes block once. Hoever, if the found key node has no value
+ * (key-only node), this does nothing. So don't use this for testing the
+ * key-value pair existence.
+ */
+#define xbc_node_for_each_array_value(node, key, anode, value) \
+ for (value = xbc_node_find_value(node, key, &anode); value != NULL; \
+ anode = xbc_node_get_next(anode), \
+ value = anode ? xbc_node_get_data(anode) : NULL)
+
+/**
+ * xbc_node_for_each_key_value() - Iterate key-value pairs under a node
+ * @node: An XBC node.
+ * @knode: Iterated key node
+ * @value: Iterated value string
+ *
+ * Iterate key-value pairs under @node. Each key node and value string are
+ * stored in @knode and @value respectively.
+ */
+#define xbc_node_for_each_key_value(node, knode, value) \
+ for (knode = NULL, value = xbc_node_find_next_key_value(node, &knode);\
+ knode != NULL; value = xbc_node_find_next_key_value(node, &knode))
+
+/**
+ * xbc_for_each_key_value() - Iterate key-value pairs
+ * @knode: Iterated key node
+ * @value: Iterated value string
+ *
+ * Iterate key-value pairs in whole XBC tree. Each key node and value string
+ * are stored in @knode and @value respectively.
+ */
+#define xbc_for_each_key_value(knode, value) \
+ xbc_node_for_each_key_value(NULL, knode, value)
+
+/* Compose partial key */
+int __init xbc_node_compose_key_after(struct xbc_node *root,
+ struct xbc_node *node, char *buf, size_t size);
+
+/**
+ * xbc_node_compose_key() - Compose full key string of the XBC node
+ * @node: An XBC node.
+ * @buf: A buffer to store the key.
+ * @size: The size of the @buf.
+ *
+ * Compose the full-length key of the @node into @buf. Returns the total
+ * length of the key stored in @buf. Or returns -EINVAL if @node is NULL,
+ * and -ERANGE if the key depth is deeper than max depth.
+ */
+static inline int __init xbc_node_compose_key(struct xbc_node *node,
+ char *buf, size_t size)
+{
+ return xbc_node_compose_key_after(NULL, node, buf, size);
+}
+
+/* XBC node initializer */
+int __init xbc_init(char *buf);
+
+/* XBC cleanup data structures */
+void __init xbc_destroy_all(void);
+
+/* Debug dump functions */
+void __init xbc_debug_dump(void);
+
+#endif
diff --git a/init/Kconfig b/init/Kconfig
index a34064a031a5..63450d3bbf12 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1215,6 +1215,17 @@ source "usr/Kconfig"

endif

+config BOOT_CONFIG
+ bool "Boot config support"
+ select LIBXBC
+ default y
+ help
+ Extra boot config allows system admin to pass a config file as
+ complemental extension of kernel cmdline when booting.
+ The boot config file is usually attached at the end of initramfs.
+
+ If unsure, say Y.
+
choice
prompt "Compiler optimization level"
default CC_OPTIMIZE_FOR_PERFORMANCE
diff --git a/lib/Kconfig b/lib/Kconfig
index 6e790dc55c5b..10012b646009 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -566,6 +566,9 @@ config DIMLIB
config LIBFDT
bool

+config LIBXBC
+ bool
+
config OID_REGISTRY
tristate
help
diff --git a/lib/Makefile b/lib/Makefile
index 93217d44237f..75a64d2552a2 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -228,6 +228,8 @@ $(foreach file, $(libfdt_files), \
$(eval CFLAGS_$(file) = -I $(srctree)/scripts/dtc/libfdt))
lib-$(CONFIG_LIBFDT) += $(libfdt_files)

+lib-$(CONFIG_LIBXBC) += bootconfig.o
+
obj-$(CONFIG_RBTREE_TEST) += rbtree_test.o
obj-$(CONFIG_INTERVAL_TREE_TEST) += interval_tree_test.o

diff --git a/lib/bootconfig.c b/lib/bootconfig.c
new file mode 100644
index 000000000000..055014e233a5
--- /dev/null
+++ b/lib/bootconfig.c
@@ -0,0 +1,803 @@
+// 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);
+ }
+ }
+ }
+
+ 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)
+ 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 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)
+ return -EBUSY;
+
+ ret = strlen(buf);
+ if (ret > XBC_DATA_MAX - 1 || ret == 0)
+ 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();
+
+ 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);
+ }
+}