libfdt: Add fdt_path_offset_namelen

Add a namelen variant of fdt_path_offset to retrieve the node offset using only a fixed number of characters. Reviewed-by: Simon Glass <sjg@chromium.org> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

libfdt: Add fdt_path_offset_namelen
Add a namelen variant of fdt_path_offset to retrieve the node offset using only a fixed number of characters. Reviewed-by: Simon Glass <sjg@chromium.org> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Maxime Ripard · Tom Rini
1 parent 6f5f92c60b
Showing 2 changed files with 25 additions and 9 deletions Side-by-side Diff
include/libfdt.h
lib/libfdt/fdt_ro.c
@@ -366,6 +366,17 @@
 int fdt_subnode_offset(const void *fdt, int parentoffset, const char *name);
  
 /**
+ * fdt_path_offset_namelen - find a tree node based on substring
+ * @fdt: pointer to the device tree blob
+ * @path: full path of the node to locate
+ * @namelen: number of characters of name to consider
+ *
+ * Identical to fdt_path_offset(), but only examine the first
+ * namelen characters of path for matching the node path.
+ */
+int fdt_path_offset_namelen(const void *fdt, const char *path, int namelen);
+
+/**
  * fdt_path_offset - find a tree node by its full path
  * @fdt: pointer to the device tree blob
  * @path: full path of the node to locate
@@ -387,7 +398,10 @@
  *	-FDT_ERR_BADSTRUCTURE,
  *	-FDT_ERR_TRUNCATED, standard meanings.
  */
-int fdt_path_offset(const void *fdt, const char *path);
+static inline int fdt_path_offset(const void *fdt, const char *path)
+{
+	return fdt_path_offset_namelen(fdt, path, strlen(path));
+}
  
 /**
  * fdt_get_name - retrieve the name of a given node
@@ -145,10 +145,10 @@
  * "foo/bar:option" and "bar:option/otheroption", both of which happen, so
  * first searching for either ':' or '/' does not work.
  */
-static const char *fdt_path_next_separator(const char *path)
+static const char *fdt_path_next_separator(const char *path, int len)
 {
-	const char *sep1 = strchr(path, '/');
-	const char *sep2 = strchr(path, ':');
+	const void *sep1 = memchr(path, '/', len);
+	const void *sep2 = memchr(path, ':', len);
  
 	if (sep1 && sep2)
 		return (sep1 < sep2) ? sep1 : sep2;
  
@@ -158,9 +158,9 @@
 		return sep2;
 }
  
-int fdt_path_offset(const void *fdt, const char *path)
+int fdt_path_offset_namelen(const void *fdt, const char *path, int namelen)
 {
-	const char *end = path + strlen(path);
+	const char *end = path + namelen;
 	const char *p = path;
 	int offset = 0;
  
@@ -168,7 +168,7 @@
  
 	/* see if we have an alias */
 	if (*path != '/') {
-		const char *q = fdt_path_next_separator(path);
+		const char *q = fdt_path_next_separator(path, namelen);
  
 		if (!q)
 			q = end;
  
  
@@ -181,14 +181,16 @@
 		p = q;
 	}
  
-	while (*p) {
+	while (*p && (p < end)) {
 		const char *q;
  
 		while (*p == '/')
 			p++;
+
 		if (*p == '\0' || *p == ':')
 			return offset;
-		q = fdt_path_next_separator(p);
+
+		q = fdt_path_next_separator(p, end - p);
 		if (!q)
 			q = end;
...	...	@@ -366,6 +366,17 @@
366	366	int fdt_subnode_offset(const void fdt, int parentoffset, const char name);
367	367
368	368	/**
	369	+ * fdt_path_offset_namelen - find a tree node based on substring
	370	+ * @fdt: pointer to the device tree blob
	371	+ * @path: full path of the node to locate
	372	+ * @namelen: number of characters of name to consider
	373	+ *
	374	+ * Identical to fdt_path_offset(), but only examine the first
	375	+ * namelen characters of path for matching the node path.
	376	+ */
	377	+int fdt_path_offset_namelen(const void fdt, const char path, int namelen);
	378	+
	379	+/**
369	380	* fdt_path_offset - find a tree node by its full path
370	381	* @fdt: pointer to the device tree blob
371	382	* @path: full path of the node to locate
...	...	@@ -387,7 +398,10 @@
387	398	* -FDT_ERR_BADSTRUCTURE,
388	399	* -FDT_ERR_TRUNCATED, standard meanings.
389	400	*/
390		-int fdt_path_offset(const void fdt, const char path);
	401	+static inline int fdt_path_offset(const void fdt, const char path)
	402	+{
	403	+ return fdt_path_offset_namelen(fdt, path, strlen(path));
	404	+}
391	405
392	406	/**
393	407	* fdt_get_name - retrieve the name of a given node
...	...	@@ -145,10 +145,10 @@
145	145	* "foo/bar:option" and "bar:option/otheroption", both of which happen, so
146	146	* first searching for either ':' or '/' does not work.
147	147	*/
148		-static const char fdt_path_next_separator(const char path)
	148	+static const char fdt_path_next_separator(const char path, int len)
149	149	{
150		- const char *sep1 = strchr(path, '/');
151		- const char *sep2 = strchr(path, ':');
	150	+ const void *sep1 = memchr(path, '/', len);
	151	+ const void *sep2 = memchr(path, ':', len);
152	152
153	153	if (sep1 && sep2)
154	154	return (sep1 < sep2) ? sep1 : sep2;
155	155
...	...	@@ -158,9 +158,9 @@
158	158	return sep2;
159	159	}
160	160
161		-int fdt_path_offset(const void fdt, const char path)
	161	+int fdt_path_offset_namelen(const void fdt, const char path, int namelen)
162	162	{
163		- const char *end = path + strlen(path);
	163	+ const char *end = path + namelen;
164	164	const char *p = path;
165	165	int offset = 0;
166	166
...	...	@@ -168,7 +168,7 @@
168	168
169	169	/* see if we have an alias */
170	170	if (*path != '/') {
171		- const char *q = fdt_path_next_separator(path);
	171	+ const char *q = fdt_path_next_separator(path, namelen);
172	172
173	173	if (!q)
174	174	q = end;
175	175
176	176
...	...	@@ -181,14 +181,16 @@
181	181	p = q;
182	182	}
183	183
184		- while (*p) {
	184	+ while (*p && (p < end)) {
185	185	const char *q;
186	186
187	187	while (*p == '/')
188	188	p++;
	189	+
189	190	if (p == '\0' \|\| p == ':')
190	191	return offset;
191		- q = fdt_path_next_separator(p);
	192	+
	193	+ q = fdt_path_next_separator(p, end - p);
192	194	if (!q)
193	195	q = end;
194	196