[PATCH v2 2/4] bootconfig: Support mixing a value and subkeys under a key

Masami Hiramatsu
2021-05-21T06:34:54Z

Support mixing a value and subkeys under a key. Since kernel cmdline
options will support "aaa.bbb=value1 aaa.bbb.ccc=value2", it is
better that the bootconfig supports such configuration too.

Note that this does not change syntax itself but just accepts
mixed value and subkeys e.g.

key = value1
key.subkey = value2

But this is not accepted;

key {
value1
subkey = value2
}

That will make value1 as a subkey.

Also, the order of the value node under a key is fixed. If there
are a value and subkeys, the value is always the first child node
of the key. Thus if user specifies subkeys first, e.g.

key.subkey = value1
key = value2

In the program (and /proc/bootconfig), it will be shown as below

key = value2
key.subkey = value1

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
include/linux/bootconfig.h | 32 ++++++++++++++++++++++
lib/bootconfig.c | 65 ++++++++++++++++++++++++++++++--------------
tools/bootconfig/main.c | 45 +++++++++++++++++++++++++-----
3 files changed, 114 insertions(+), 28 deletions(-)

diff --git a/include/linux/bootconfig.h b/include/linux/bootconfig.h
index 3178a31fdabc..e49043ac77c9 100644
--- a/include/linux/bootconfig.h
+++ b/include/linux/bootconfig.h
@@ -80,6 +80,8 @@ static inline __init bool xbc_node_is_array(struct xbc_node *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.
+ * Note that the leaf node can have subkey nodes in addition to the
+ * value node.
*/
static inline __init bool xbc_node_is_leaf(struct xbc_node *node)
{
@@ -129,6 +131,23 @@ static inline struct xbc_node * __init xbc_find_node(const char *key)
return xbc_node_find_child(NULL, key);
}

+/**
+ * xbc_node_get_subkey() - Return the first subkey node if exists
+ * @node: Parent node
+ *
+ * Return the first subkey node of the @node. If the @node has no child
+ * or only value node, this will return NULL.
+ */
+static inline struct xbc_node * __init xbc_node_get_subkey(struct xbc_node *node)
+{
+ struct xbc_node *child = xbc_node_get_child(node);
+
+ if (child && xbc_node_is_value(child))
+ return xbc_node_get_next(child);
+ else
+ return child;
+}
+
/**
* xbc_array_for_each_value() - Iterate value nodes on an array
* @anode: An XBC arraied value node
@@ -149,11 +168,24 @@ static inline struct xbc_node * __init xbc_find_node(const char *key)
* @child: Iterated XBC node.
*
* Iterate child nodes of @parent. Each child nodes are stored to @child.
+ * The @child can be mixture of a value node and subkey nodes.
*/
#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_subkey() - Iterate child subkey nodes
+ * @parent: An XBC node.
+ * @child: Iterated XBC node.
+ *
+ * Iterate subkey nodes of @parent. Each child nodes are stored to @child.
+ * The @child is only the subkey node.
+ */
+#define xbc_node_for_each_subkey(parent, child) \
+ for (child = xbc_node_get_subkey(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.
diff --git a/lib/bootconfig.c b/lib/bootconfig.c
index 44dcdcbd746a..927017431fb6 100644
--- a/lib/bootconfig.c
+++ b/lib/bootconfig.c
@@ -156,7 +156,7 @@ xbc_node_find_child(struct xbc_node *parent, const char *key)
struct xbc_node *node;

if (parent)
- node = xbc_node_get_child(parent);
+ node = xbc_node_get_subkey(parent);
else
node = xbc_root_node();

@@ -164,7 +164,7 @@ xbc_node_find_child(struct xbc_node *parent, const char *key)
if (!xbc_node_match_prefix(node, &key))
node = xbc_node_get_next(node);
else if (*key != '\0')
- node = xbc_node_get_child(node);
+ node = xbc_node_get_subkey(node);
else
break;
}
@@ -274,6 +274,8 @@ int __init xbc_node_compose_key_after(struct xbc_node *root,
struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root,
struct xbc_node *node)
{
+ struct xbc_node *next;
+
if (unlikely(!xbc_data))
return NULL;

@@ -282,6 +284,13 @@ struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root,
if (!node)
node = xbc_nodes;
} else {
+ /* Leaf node may have a subkey */
+ next = xbc_node_get_subkey(node);
+ if (next) {
+ node = next;
+ goto found;
+ }
+
if (node == root) /* @root was a leaf, no child node. */
return NULL;

@@ -296,6 +305,7 @@ struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root,
node = xbc_node_get_next(node);
}

+found:
while (node && !xbc_node_is_leaf(node))
node = xbc_node_get_child(node);

@@ -375,18 +385,20 @@ static inline __init struct xbc_node *xbc_last_child(struct xbc_node *node)
return node;
}

-static struct xbc_node * __init xbc_add_sibling(char *data, u32 flag)
+static struct xbc_node * __init __xbc_add_sibling(char *data, u32 flag, bool head)
{
struct xbc_node *sib, *node = xbc_add_node(data, flag);

if (node) {
if (!last_parent) {
+ /* Ignore @head in this case */
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) {
+ if (!last_parent->child || head) {
+ node->next = last_parent->child;
last_parent->child = xbc_node_index(node);
} else {
sib = xbc_node_get_child(last_parent);
@@ -400,6 +412,16 @@ static struct xbc_node * __init xbc_add_sibling(char *data, u32 flag)
return node;
}

+static inline struct xbc_node * __init xbc_add_sibling(char *data, u32 flag)
+{
+ return __xbc_add_sibling(data, flag, false);
+}
+
+static inline struct xbc_node * __init xbc_add_head_sibling(char *data, u32 flag)
+{
+ return __xbc_add_sibling(data, flag, true);
+}
+
static inline __init struct xbc_node *xbc_add_child(char *data, u32 flag)
{
struct xbc_node *node = xbc_add_sibling(data, flag);
@@ -568,8 +590,9 @@ static int __init __xbc_add_key(char *k)
node = find_match_node(xbc_nodes, k);
else {
child = xbc_node_get_child(last_parent);
+ /* Since the value node is the first child, skip it. */
if (child && xbc_node_is_value(child))
- return xbc_parse_error("Subkey is mixed with value", k);
+ child = xbc_node_get_next(child);
node = find_match_node(child, k);
}

@@ -612,27 +635,29 @@ static int __init xbc_parse_kv(char **k, char *v, int op)
if (ret)
return ret;

- child = xbc_node_get_child(last_parent);
- if (child) {
- if (xbc_node_is_key(child))
- return xbc_parse_error("Value is mixed with subkey", v);
- else if (op == '=')
- return xbc_parse_error("Value is redefined", v);
- }
-
c = __xbc_parse_value(&v, &next);
if (c < 0)
return c;

- if (op == ':' && child) {
- xbc_init_node(child, v, XBC_VALUE);
- } else {
- if (op == '+' && child)
- last_parent = xbc_last_child(child);
- if (!xbc_add_sibling(v, XBC_VALUE))
- return -ENOMEM;
+ child = xbc_node_get_child(last_parent);
+ if (child && xbc_node_is_value(child)) {
+ if (op == '=')
+ return xbc_parse_error("Value is redefined", v);
+ if (op == ':') {
+ unsigned short nidx = child->next;
+
+ xbc_init_node(child, v, XBC_VALUE);
+ child->next = nidx; /* keep subkeys */
+ goto array;
+ }
+ /* op must be '+' */
+ last_parent = xbc_last_child(child);
}
+ /* The value node should always be the first child */
+ if (!xbc_add_head_sibling(v, XBC_VALUE))
+ return -ENOMEM;

+array:
if (c == ',') { /* Array */
c = xbc_parse_array(&next);
if (c < 0)
diff --git a/tools/bootconfig/main.c b/tools/bootconfig/main.c
index 7a98756e594a..f5b564206428 100644
--- a/tools/bootconfig/main.c
+++ b/tools/bootconfig/main.c
@@ -35,30 +35,55 @@ static int xbc_show_value(struct xbc_node *node, bool semicolon)

static void xbc_show_compact_tree(void)
{
- struct xbc_node *node, *cnode;
+ struct xbc_node *node, *cnode = NULL, *vnode;
int depth = 0, i;

node = xbc_root_node();
while (node && xbc_node_is_key(node)) {
for (i = 0; i < depth; i++)
printf("\t");
- cnode = xbc_node_get_child(node);
+ if (!cnode)
+ cnode = xbc_node_get_child(node);
while (cnode && xbc_node_is_key(cnode) && !cnode->next) {
+ vnode = xbc_node_get_child(cnode);
+ /*
+ * If @cnode has value and subkeys, this
+ * should show it as below.
+ *
+ * key(@node) {
+ * key(@cnode) = value;
+ * key(@cnode) {
+ * subkeys;
+ * }
+ * }
+ */
+ if (vnode && xbc_node_is_value(vnode) && vnode->next)
+ break;
printf("%s.", xbc_node_get_data(node));
node = cnode;
- cnode = xbc_node_get_child(node);
+ cnode = vnode;
}
if (cnode && xbc_node_is_key(cnode)) {
printf("%s {\n", xbc_node_get_data(node));
depth++;
node = cnode;
+ cnode = NULL;
continue;
} else if (cnode && xbc_node_is_value(cnode)) {
printf("%s = ", xbc_node_get_data(node));
xbc_show_value(cnode, true);
+ /*
+ * If @node has value and subkeys, continue
+ * looping on subkeys with same node.
+ */
+ if (cnode->next) {
+ cnode = xbc_node_get_next(cnode);
+ continue;
+ }
} else {
printf("%s;\n", xbc_node_get_data(node));
}
+ cnode = NULL;

if (node->next) {
node = xbc_node_get_next(node);
@@ -70,10 +95,12 @@ static void xbc_show_compact_tree(void)
return;
if (!xbc_node_get_child(node)->next)
continue;
- depth--;
- for (i = 0; i < depth; i++)
- printf("\t");
- printf("}\n");
+ if (depth) {
+ depth--;
+ for (i = 0; i < depth; i++)
+ printf("\t");
+ printf("}\n");
+ }
}
node = xbc_node_get_next(node);
}
@@ -88,8 +115,10 @@ static void xbc_show_list(void)

xbc_for_each_key_value(leaf, val) {
ret = xbc_node_compose_key(leaf, key, XBC_KEYLEN_MAX);
- if (ret < 0)
+ if (ret < 0) {
+ fprintf(stderr, "Failed to compose key %d\n", ret);
break;
+ }
printf("%s = ", key);
if (!val || val[0] == '\0') {
printf("\"\"\n");