diff options
Diffstat (limited to 'lib/bootconfig.c')
| -rw-r--r-- | lib/bootconfig.c | 814 |
1 files changed, 814 insertions, 0 deletions
diff --git a/lib/bootconfig.c b/lib/bootconfig.c new file mode 100644 index 000000000000..afb2e767e6fe --- /dev/null +++ b/lib/bootconfig.c @@ -0,0 +1,814 @@ +// 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); + } +} |