bootconfig: Support mixing a value and subkeys under a key

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

Link: https://lkml.kernel.org/r/162262194685.264090.7738574774030567419.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/include/linux/bootconfig.h b/include/linux/bootconfig.h
index 3178a31..e49043a 100644 (file)
--- 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 44dcdcb..9270174 100644 (file)
--- 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 23569fb..62a3b50 100644 (file)
--- 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);
        }
@@ -86,8 +113,10 @@ static void xbc_show_list(void)
        const char *val;
 
        xbc_for_each_key_value(leaf, val) {
-               if (xbc_node_compose_key(leaf, key, XBC_KEYLEN_MAX) < 0)
+               if (xbc_node_compose_key(leaf, key, XBC_KEYLEN_MAX) < 0) {
+                       fprintf(stderr, "Failed to compose key %d\n", ret);
                        break;
+               }
                printf("%s = ", key);
                if (!val || val[0] == '\0') {
                        printf("\"\"\n");