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>

diff --git a/include/libfdt.h b/include/libfdt.h
index 4643be5adf3982fda14e843efa604971f940d9ac..f13b01f08f71e23808199b9cde80011e547dbd8f 100644 (file)
--- a/include/libfdt.h
+++ b/include/libfdt.h
@@ -365,6 +365,17 @@ int fdt_subnode_offset_namelen(const void *fdt, int parentoffset,
  */
 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
@@ -387,7 +398,10 @@ int fdt_subnode_offset(const void *fdt, int parentoffset, const char *name);
  *     -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

diff --git a/lib/libfdt/fdt_ro.c b/lib/libfdt/fdt_ro.c
index 6b737b211d2eeead39b5337fe1de412dc762d223..9cc98db6e2bf8942b4b15a8599d14c02c19b51f4 100644 (file)
--- a/lib/libfdt/fdt_ro.c
+++ b/lib/libfdt/fdt_ro.c
@@ -145,10 +145,10 @@ int fdt_subnode_offset(const void *fdt, int parentoffset,
  * "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 @@ static const char *fdt_path_next_separator(const char *path)
                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 @@ int fdt_path_offset(const void *fdt, const char *path)
 
        /* 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 @@ int fdt_path_offset(const void *fdt, const char *path)
                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;