dtc: Add ability to delete nodes and properties

dtc currently allows the contents of properties to be changed, and the
contents of nodes to be added to. There are situations where removing
properties or nodes may be useful. This change implements the following
syntax to do that:

    / {
        /delete-property/ propname;
        /delete-node/ nodename;
    };

or:

    /delete-node/ &noderef;

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 112 insertions, 13 deletions

diff --git a/livetree.c b/livetree.c
index c9209d5..e856662 100644
--- a/livetree.c
+++ b/livetree.c
@@ -29,9 +29,11 @@ void add_label(struct label **labels, char *label)
 	struct label *new;
 
 	/* Make sure the label isn't already there */
-	for_each_label(*labels, new)
-		if (streq(new->label, label))
+	for_each_label_withdel(*labels, new)
+		if (streq(new->label, label)) {
+			new->deleted = 0;
 			return;
+		}
 
 	new = xmalloc(sizeof(*new));
 	new->label = label;
@@ -39,6 +41,14 @@ void add_label(struct label **labels, char *label)
 	*labels = new;
 }
 
+void delete_labels(struct label **labels)
+{
+	struct label *label;
+
+	for_each_label(*labels, label)
+		label->deleted = 1;
+}
+
 struct property *build_property(char *name, struct data val)
 {
 	struct property *new = xmalloc(sizeof(*new));
@@ -51,6 +61,18 @@ struct property *build_property(char *name, struct data val)
 	return new;
 }
 
+struct property *build_property_delete(char *name)
+{
+	struct property *new = xmalloc(sizeof(*new));
+
+	memset(new, 0, sizeof(*new));
+
+	new->name = name;
+	new->deleted = 1;
+
+	return new;
+}
+
 struct property *chain_property(struct property *first, struct property *list)
 {
 	assert(first->next == NULL);
@@ -91,6 +113,17 @@ struct node *build_node(struct property *proplist, struct node *children)
 	return new;
 }
 
+struct node *build_node_delete(void)
+{
+	struct node *new = xmalloc(sizeof(*new));
+
+	memset(new, 0, sizeof(*new));
+
+	new->deleted = 1;
+
+	return new;
+}
+
 struct node *name_node(struct node *node, char *name)
 {
 	assert(node->name == NULL);
@@ -106,8 +139,10 @@ struct node *merge_nodes(struct node *old_node, struct node *new_node)
 	struct node *new_child, *old_child;
 	struct label *l;
 
+	old_node->deleted = 0;
+
 	/* Add new node labels to old node */
-	for_each_label(new_node->labels, l)
+	for_each_label_withdel(new_node->labels, l)
 		add_label(&old_node->labels, l->label);
 
 	/* Move properties from the new node to the old node.  If there
@@ -118,14 +153,21 @@ struct node *merge_nodes(struct node *old_node, struct node *new_node)
 		new_node->proplist = new_prop->next;
 		new_prop->next = NULL;
 
+		if (new_prop->deleted) {
+			delete_property_by_name(old_node, new_prop->name);
+			free(new_prop);
+			continue;
+		}
+
 		/* Look for a collision, set new value if there is */
-		for_each_property(old_node, old_prop) {
+		for_each_property_withdel(old_node, old_prop) {
 			if (streq(old_prop->name, new_prop->name)) {
 				/* Add new labels to old property */
-				for_each_label(new_prop->labels, l)
+				for_each_label_withdel(new_prop->labels, l)
 					add_label(&old_prop->labels, l->label);
 
 				old_prop->val = new_prop->val;
+				old_prop->deleted = 0;
 				free(new_prop);
 				new_prop = NULL;
 				break;
@@ -146,8 +188,14 @@ struct node *merge_nodes(struct node *old_node, struct node *new_node)
 		new_child->parent = NULL;
 		new_child->next_sibling = NULL;
 
+		if (new_child->deleted) {
+			delete_node_by_name(old_node, new_child->name);
+			free(new_child);
+			continue;
+		}
+
 		/* Search for a collision.  Merge if there is */
-		for_each_child(old_node, old_child) {
+		for_each_child_withdel(old_node, old_child) {
 			if (streq(old_child->name, new_child->name)) {
 				merge_nodes(old_child, new_child);
 				new_child = NULL;
@@ -188,6 +236,25 @@ void add_property(struct node *node, struct property *prop)
 	*p = prop;
 }
 
+void delete_property_by_name(struct node *node, char *name)
+{
+	struct property *prop = node->proplist;
+
+	while (prop) {
+		if (!strcmp(prop->name, name)) {
+			delete_property(prop);
+			return;
+		}
+		prop = prop->next;
+	}
+}
+
+void delete_property(struct property *prop)
+{
+	prop->deleted = 1;
+	delete_labels(&prop->labels);
+}
+
 void add_child(struct node *parent, struct node *child)
 {
 	struct node **p;
@@ -202,6 +269,32 @@ void add_child(struct node *parent, struct node *child)
 	*p = child;
 }
 
+void delete_node_by_name(struct node *parent, char *name)
+{
+	struct node *node = parent->children;
+
+	while (node) {
+		if (!strcmp(node->name, name)) {
+			delete_node(node);
+			return;
+		}
+		node = node->next_sibling;
+	}
+}
+
+void delete_node(struct node *node)
+{
+	struct property *prop;
+	struct node *child;
+
+	node->deleted = 1;
+	for_each_child(node, child)
+		delete_node(child);
+	for_each_property(node, prop)
+		delete_property(prop);
+	delete_labels(&node->labels);
+}
+
 struct reserve_info *build_reserve_entry(uint64_t address, uint64_t size)
 {
 	struct reserve_info *new = xmalloc(sizeof(*new));
@@ -353,8 +446,11 @@ struct node *get_node_by_path(struct node *tree, const char *path)
 	const char *p;
 	struct node *child;
 
-	if (!path || ! (*path))
+	if (!path || ! (*path)) {
+		if (tree->deleted)
+			return NULL;
 		return tree;
+	}
 
 	while (path[0] == '/')
 		path++;
@@ -397,8 +493,11 @@ struct node *get_node_by_phandle(struct node *tree, cell_t phandle)
 
 	assert((phandle != 0) && (phandle != -1));
 
-	if (tree->phandle == phandle)
+	if (tree->phandle == phandle) {
+		if (tree->deleted)
+			return NULL;
 		return tree;
+	}
 
 	for_each_child(tree, child) {
 		node = get_node_by_phandle(child, phandle);
@@ -535,7 +634,7 @@ static void sort_properties(struct node *node)
 	int n = 0, i = 0;
 	struct property *prop, **tbl;
 
-	for_each_property(node, prop)
+	for_each_property_withdel(node, prop)
 		n++;
 
 	if (n == 0)
@@ -543,7 +642,7 @@ static void sort_properties(struct node *node)
 
 	tbl = xmalloc(n * sizeof(*tbl));
 
-	for_each_property(node, prop)
+	for_each_property_withdel(node, prop)
 		tbl[i++] = prop;
 
 	qsort(tbl, n, sizeof(*tbl), cmp_prop);
@@ -571,7 +670,7 @@ static void sort_subnodes(struct node *node)
 	int n = 0, i = 0;
 	struct node *subnode, **tbl;
 
-	for_each_child(node, subnode)
+	for_each_child_withdel(node, subnode)
 		n++;
 
 	if (n == 0)
@@ -579,7 +678,7 @@ static void sort_subnodes(struct node *node)
 
 	tbl = xmalloc(n * sizeof(*tbl));
 
-	for_each_child(node, subnode)
+	for_each_child_withdel(node, subnode)
 		tbl[i++] = subnode;
 
 	qsort(tbl, n, sizeof(*tbl), cmp_subnode);
@@ -598,7 +697,7 @@ static void sort_node(struct node *node)
 
 	sort_properties(node);
 	sort_subnodes(node);
-	for_each_child(node, c)
+	for_each_child_withdel(node, c)
 		sort_node(c);
 }