[fdt] Avoid temporarily modifying path during path lookup

Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/core/fdt.c b/src/core/fdt.c
index 2ca41bc08d928c9df79975ddc72424d93e4b65ab..714dba13b8d43d1cc79ce2eebdef3b9add70ef49 100644 (file)
--- a/src/core/fdt.c
+++ b/src/core/fdt.c
@@ -201,6 +201,8 @@ static int fdt_child ( struct fdt *fdt, unsigned int offset, const char *name,
        struct fdt_cursor pos;
        struct fdt_descriptor desc;
        unsigned int orig_offset;
+       const char *sep;
+       size_t name_len;
        int rc;
 
        /* Record original offset (for debugging) */
@@ -210,6 +212,10 @@ static int fdt_child ( struct fdt *fdt, unsigned int offset, const char *name,
        pos.offset = offset;
        pos.depth = -1;
 
+       /* Determine length of name (may be terminated with NUL or '/') */
+       sep = strchr ( name, '/' );
+       name_len = ( sep ? ( ( size_t ) ( sep - name ) ) : strlen ( name ) );
+
        /* Find child node */
        while ( 1 ) {
 
@@ -227,7 +233,9 @@ static int fdt_child ( struct fdt *fdt, unsigned int offset, const char *name,
                if ( ( pos.depth == 1 ) && desc.name && ( ! desc.data ) ) {
                        DBGC2 ( fdt, "FDT +%#04x has child node \"%s\"\n",
                                orig_offset, desc.name );
-                       if ( strcmp ( name, desc.name ) == 0 ) {
+                       if ( ( strlen ( desc.name ) == name_len ) &&
+                            ( memcmp ( name, desc.name, name_len ) == 0 ) ) {
+                               *child = desc.offset;
                                DBGC2 ( fdt, "FDT +%#04x found child node "
                                        "\"%s\" at +%#04x\n", orig_offset,
                                        desc.name, *child );
@@ -290,8 +298,7 @@ static int fdt_end ( struct fdt *fdt, unsigned int offset,
  * @ret rc             Return status code
  */
 int fdt_path ( struct fdt *fdt, const char *path, unsigned int *offset ) {
-       char *tmp = ( ( char * ) path );
-       char *del;
+       const char *tmp = path;
        int rc;
 
        /* Initialise offset */
@@ -308,24 +315,14 @@ int fdt_path ( struct fdt *fdt, const char *path, unsigned int *offset ) {
                if ( ! *tmp )
                        break;
 
-               /* Find next '/' delimiter and convert to NUL */
-               del = strchr ( tmp, '/' );
-               if ( del )
-                       *del = '\0';
-
-               /* Find child and restore delimiter */
-               rc = fdt_child ( fdt, *offset, tmp, offset );
-               if ( del )
-                       *del = '/';
-               if ( rc != 0 )
+               /* Find child */
+               if ( ( rc = fdt_child ( fdt, *offset, tmp, offset ) ) != 0 )
                        return rc;
 
-               /* Terminate if there are no more delimiters */
-               if ( ! del )
+               /* Move to next path component, if any */
+               tmp = strchr ( tmp, '/' );
+               if ( ! tmp )
                        break;
-
-               /* Move to next path component */
-               tmp = del;
        }
 
        DBGC2 ( fdt, "FDT found path \"%s\" at +%#04x\n", path, *offset );