libfdt: Add fdt_setprop_namelen()

Allow specifying name length in setprop similar to `fdt_get_property_namelen` functions. Signed-off-by: Ayush Singh <ayush@beagleboard.org> Message-ID: <20241205-setprop-namelen-v2-3-0d85a3d2e7b1@beagleboard.org> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
dgibson · Dec 6, 2024 · bdca861 · bdca861
1 parent 0f69ced
commit bdca861
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Showing 3 changed files with 103 additions and 21 deletions.
diff --git a/libfdt/fdt_rw.c b/libfdt/fdt_rw.c
@@ -124,31 +124,33 @@ static int fdt_splice_string_(void *fdt, int newlen)
  *	allocated. Ignored if can_assume(NO_ROLLBACK)
  * @return offset of string in the string table (whether found or added)
  */
-static int fdt_find_add_string_(void *fdt, const char *s, int *allocated)
+static int fdt_find_add_string_(void *fdt, const char *s, int slen,
+				int *allocated)
 {
 	char *strtab = (char *)fdt + fdt_off_dt_strings(fdt);
 	const char *p;
 	char *new;
-	int len = strlen(s) + 1;
 	int err;
 
 	if (!can_assume(NO_ROLLBACK))
 		*allocated = 0;
 
-	p = fdt_find_string_(strtab, fdt_size_dt_strings(fdt), s);
+	p = fdt_find_string_len_(strtab, fdt_size_dt_strings(fdt), s, slen);
 	if (p)
 		/* found it */
 		return (p - strtab);
 
 	new = strtab + fdt_size_dt_strings(fdt);
-	err = fdt_splice_string_(fdt, len);
+	err = fdt_splice_string_(fdt, slen + 1);
 	if (err)
 		return err;
 
 	if (!can_assume(NO_ROLLBACK))
 		*allocated = 1;
 
-	memcpy(new, s, len);
+	memcpy(new, s, slen);
+	new[slen] = '\0';
+
 	return (new - strtab);
 }
 
@@ -181,13 +183,15 @@ int fdt_del_mem_rsv(void *fdt, int n)
 	return fdt_splice_mem_rsv_(fdt, re, 1, 0);
 }
 
-static int fdt_resize_property_(void *fdt, int nodeoffset, const char *name,
+static int fdt_resize_property_(void *fdt, int nodeoffset,
+				const char *name, int namelen,
 				int len, struct fdt_property **prop)
 {
 	int oldlen;
 	int err;
 
-	*prop = fdt_get_property_w(fdt, nodeoffset, name, &oldlen);
+	*prop = fdt_get_property_namelen_w(fdt, nodeoffset, name, namelen,
+					   &oldlen);
 	if (!*prop)
 		return oldlen;
 
@@ -200,7 +204,7 @@ static int fdt_resize_property_(void *fdt, int nodeoffset, const char *name,
 }
 
 static int fdt_add_property_(void *fdt, int nodeoffset, const char *name,
-			     int len, struct fdt_property **prop)
+			     int namelen, int len, struct fdt_property **prop)
 {
 	int proplen;
 	int nextoffset;
@@ -211,7 +215,7 @@ static int fdt_add_property_(void *fdt, int nodeoffset, const char *name,
 	if ((nextoffset = fdt_check_node_offset_(fdt, nodeoffset)) < 0)
 		return nextoffset;
 
-	namestroff = fdt_find_add_string_(fdt, name, &allocated);
+	namestroff = fdt_find_add_string_(fdt, name, namelen, &allocated);
 	if (namestroff < 0)
 		return namestroff;
 
@@ -255,31 +259,33 @@ int fdt_set_name(void *fdt, int nodeoffset, const char *name)
 	return 0;
 }
 
-int fdt_setprop_placeholder(void *fdt, int nodeoffset, const char *name,
-			    int len, void **prop_data)
+int fdt_setprop_placeholder_namelen(void *fdt, int nodeoffset, const char *name,
+				    int namelen, int len, void **prop_data)
 {
 	struct fdt_property *prop;
 	int err;
 
 	FDT_RW_PROBE(fdt);
 
-	err = fdt_resize_property_(fdt, nodeoffset, name, len, &prop);
+	err = fdt_resize_property_(fdt, nodeoffset, name, namelen, len, &prop);
 	if (err == -FDT_ERR_NOTFOUND)
-		err = fdt_add_property_(fdt, nodeoffset, name, len, &prop);
+		err = fdt_add_property_(fdt, nodeoffset, name, namelen, len,
+					&prop);
 	if (err)
 		return err;
 
 	*prop_data = prop->data;
 	return 0;
 }
 
-int fdt_setprop(void *fdt, int nodeoffset, const char *name,
-		const void *val, int len)
+int fdt_setprop_namelen(void *fdt, int nodeoffset, const char *name,
+			int namelen, const void *val, int len)
 {
 	void *prop_data;
 	int err;
 
-	err = fdt_setprop_placeholder(fdt, nodeoffset, name, len, &prop_data);
+	err = fdt_setprop_placeholder_namelen(fdt, nodeoffset, name, namelen,
+					      len, &prop_data);
 	if (err)
 		return err;
 
@@ -307,7 +313,8 @@ int fdt_appendprop(void *fdt, int nodeoffset, const char *name,
 		prop->len = cpu_to_fdt32(newlen);
 		memcpy(prop->data + oldlen, val, len);
 	} else {
-		err = fdt_add_property_(fdt, nodeoffset, name, len, &prop);
+		err = fdt_add_property_(fdt, nodeoffset, name, strlen(name),
+					len, &prop);
 		if (err)
 			return err;
 		memcpy(prop->data, val, len);

diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
@@ -1666,6 +1666,38 @@ int fdt_del_mem_rsv(void *fdt, int n);
  */
 int fdt_set_name(void *fdt, int nodeoffset, const char *name);
 
+/**
+ * fdt_setprop_namelen - create or change a property
+ * @fdt: pointer to the device tree blob
+ * @nodeoffset: offset of the node whose property to change
+ * @name: name of the property to change
+ * @namelen: length of the name
+ * @val: pointer to data to set the property value to
+ * @len: length of the property value
+ *
+ * fdt_setprop_namelen() sets the value of the named property in the given
+ * node to the given value and length, creating the property if it
+ * does not already exist.
+ *
+ * This function may insert or delete data from the blob, and will
+ * therefore change the offsets of some existing nodes.
+ *
+ * returns:
+ *	0, on success
+ *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
+ *		contain the new property value
+ *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
+ *	-FDT_ERR_BADLAYOUT,
+ *	-FDT_ERR_BADMAGIC,
+ *	-FDT_ERR_BADVERSION,
+ *	-FDT_ERR_BADSTATE,
+ *	-FDT_ERR_BADSTRUCTURE,
+ *	-FDT_ERR_BADLAYOUT,
+ *	-FDT_ERR_TRUNCATED, standard meanings
+ */
+int fdt_setprop_namelen(void *fdt, int nodeoffset, const char *name,
+			int namelen, const void *val, int len);
+
 /**
  * fdt_setprop - create or change a property
  * @fdt: pointer to the device tree blob
@@ -1694,8 +1726,44 @@ int fdt_set_name(void *fdt, int nodeoffset, const char *name);
  *	-FDT_ERR_BADLAYOUT,
  *	-FDT_ERR_TRUNCATED, standard meanings
  */
-int fdt_setprop(void *fdt, int nodeoffset, const char *name,
-		const void *val, int len);
+static inline int fdt_setprop(void *fdt, int nodeoffset, const char *name,
+			      const void *val, int len)
+{
+	return fdt_setprop_namelen(fdt, nodeoffset, name, strlen(name), val,
+				   len);
+}
+
+/**
+ * fdt_setprop_placeholder_namelen - allocate space for a property
+ * @fdt: pointer to the device tree blob
+ * @nodeoffset: offset of the node whose property to change
+ * @name: name of the property to change
+ * @namelen: length of the name
+ * @len: length of the property value
+ * @prop_data: return pointer to property data
+ *
+ * fdt_setprop_placeholder_namelen() allocates the named property in the given node.
+ * If the property exists it is resized. In either case a pointer to the
+ * property data is returned.
+ *
+ * This function may insert or delete data from the blob, and will
+ * therefore change the offsets of some existing nodes.
+ *
+ * returns:
+ *	0, on success
+ *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
+ *		contain the new property value
+ *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
+ *	-FDT_ERR_BADLAYOUT,
+ *	-FDT_ERR_BADMAGIC,
+ *	-FDT_ERR_BADVERSION,
+ *	-FDT_ERR_BADSTATE,
+ *	-FDT_ERR_BADSTRUCTURE,
+ *	-FDT_ERR_BADLAYOUT,
+ *	-FDT_ERR_TRUNCATED, standard meanings
+ */
+int fdt_setprop_placeholder_namelen(void *fdt, int nodeoffset, const char *name,
+				    int namelen, int len, void **prop_data);
 
 /**
  * fdt_setprop_placeholder - allocate space for a property
@@ -1725,8 +1793,13 @@ int fdt_setprop(void *fdt, int nodeoffset, const char *name,
  *	-FDT_ERR_BADLAYOUT,
  *	-FDT_ERR_TRUNCATED, standard meanings
  */
-int fdt_setprop_placeholder(void *fdt, int nodeoffset, const char *name,
-			    int len, void **prop_data);
+static inline int fdt_setprop_placeholder(void *fdt, int nodeoffset,
+					  const char *name, int len,
+					  void **prop_data)
+{
+	return fdt_setprop_placeholder_namelen(fdt, nodeoffset, name,
+					       strlen(name), len, prop_data);
+}
 
 /**
  * fdt_setprop_u32 - set a property to a 32-bit integer

diff --git a/libfdt/version.lds b/libfdt/version.lds
@@ -43,6 +43,7 @@ LIBFDT_1.2 {
 		fdt_add_mem_rsv;
 		fdt_del_mem_rsv;
 		fdt_set_name;
+		fdt_setprop_namelen;
 		fdt_setprop;
 		fdt_delprop;
 		fdt_add_subnode_namelen;
@@ -71,6 +72,7 @@ LIBFDT_1.2 {
 		fdt_find_max_phandle;
 		fdt_generate_phandle;
 		fdt_check_full;
+		fdt_setprop_placeholder_namelen;
 		fdt_setprop_placeholder;
 		fdt_property_placeholder;
 		fdt_header_size_;