pylibfdt: add FdtRo.get_path()

Add a new Python method wrapping fdt_get_path() from the C API.

Also add a test for the new method.

Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Message-Id: <20220419194537.63170-1-luca@z3ntu.xyz>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

pylibfdt/libfdt.i

@@ -443,6 +443,29 @@ class FdtRo(object):
         """
         return fdt_get_alias(self._fdt, name)
 
+    def get_path(self, nodeoffset, quiet=()):
+        """Get the full path of a node
+
+        Args:
+            nodeoffset: Node offset to check
+
+        Returns:
+            Full path to the node
+
+        Raises:
+            FdtException if an error occurs
+        """
+        size = 1024
+        while True:
+            ret, path = fdt_get_path(self._fdt, nodeoffset, size)
+            if ret == -NOSPACE:
+                size = size * 2
+                continue
+            err = check_err(ret, quiet)
+            if err:
+                return err
+            return path
+
     def parent_offset(self, nodeoffset, quiet=()):
         """Get the offset of a node's parent
 
@@ -1115,6 +1138,11 @@ typedef uint32_t fdt32_t;
         }
 }
 
+%include "cstring.i"
+
+%cstring_output_maxsize(char *buf, int buflen);
+int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen);
+
 /* We have both struct fdt_property and a function fdt_property() */
 %warnfilter(302) fdt_property;
 

tests/pylibfdt_tests.py

@@ -348,6 +348,19 @@ class PyLibfdtBasicTests(unittest.TestCase):
         self.assertEqual("/subnode@1/subsubnode", self.fdt3.get_alias('ss1'))
         self.assertEqual("/subnode@1/subsubnode/subsubsubnode", self.fdt3.get_alias('sss1'))
 
+    def testGetPath(self):
+        """Test for the get_path() method"""
+        node = self.fdt.path_offset('/subnode@1')
+        node2 = self.fdt.path_offset('/subnode@1/subsubnode')
+        self.assertEqual("/subnode@1", self.fdt.get_path(node))
+        self.assertEqual("/subnode@1/subsubnode", self.fdt.get_path(node2))
+
+        with self.assertRaises(FdtException) as e:
+            self.fdt.get_path(-1)
+        self.assertEqual(e.exception.err, -libfdt.BADOFFSET)
+
+        self.assertEqual(-libfdt.BADOFFSET, self.fdt.get_path(-1, quiet=(libfdt.BADOFFSET,)))
+
     def testParentOffset(self):
         """Test for the parent_offset() method"""
         self.assertEqual(-libfdt.NOTFOUND,