dtc/tests/pylibfdt_tests.py

# pylibfdt - Tests for Flat Device Tree manipulation in Python
# Copyright (C) 2017 Google, Inc.
# Written by Simon Glass <sjg@chromium.org>
#
# libfdt is dual licensed: you can use it either under the terms of
# the GPL, or the BSD license, at your option.
#
#  a) This library is free software; you can redistribute it and/or
#     modify it under the terms of the GNU General Public License as
#     published by the Free Software Foundation; either version 2 of the
#     License, or (at your option) any later version.
#
#     This library is distributed in the hope that it will be useful,
#     but WITHOUT ANY WARRANTY; without even the implied warranty of
#     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#     GNU General Public License for more details.
#
#     You should have received a copy of the GNU General Public
#     License along with this library; if not, write to the Free
#     Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
#     MA 02110-1301 USA
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# Alternatively,
#
#  b) Redistribution and use in source and binary forms, with or
#     without modification, are permitted provided that the following
#     conditions are met:
#
#     1. Redistributions of source code must retain the above
#        copyright notice, this list of conditions and the following
#        disclaimer.
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import sys
import types
import unittest

sys.path.insert(0, '../pylibfdt')
import libfdt
from libfdt import FdtException, QUIET_NOTFOUND, QUIET_ALL

def get_err(err_code):
    """Convert an error code into an error message

    Args:
        err_code: Error code value (FDT_ERR_...)

    Returns:
        String error code
    """
    return 'pylibfdt error %d: %s' % (-err_code, libfdt.strerror(-err_code))

def _ReadFdt(fname):
    """Read a device tree file into an Fdt object, ready for use

    Args:
        fname: Filename to read from

    Returns:
        Fdt bytearray suitable for passing to libfdt functions
    """
    return libfdt.Fdt(open(fname).read())

class PyLibfdtTests(unittest.TestCase):
    """Test class for pylibfdt

    Properties:
        fdt: Device tree file used for testing
    """

    def setUp(self):
        """Read in the device tree we use for testing"""
        self.fdt = _ReadFdt('test_tree1.dtb')

    def GetPropList(self, node_path):
        """Read a list of properties from a node

        Args:
            node_path: Full path to node, e.g. '/subnode@1/subsubnode'

        Returns:
            List of property names for that node, e.g. ['compatible', 'reg']
        """
        prop_list = []
        node = self.fdt.path_offset(node_path)
        poffset = self.fdt.first_property_offset(node, QUIET_NOTFOUND)
        while poffset > 0:
            prop = self.fdt.get_property_by_offset(poffset)
            prop_list.append(prop.name)
            poffset = self.fdt.next_property_offset(poffset, QUIET_NOTFOUND)
        return prop_list

    def testImport(self):
        """Check that we can import the library correctly"""
        self.assertEquals(type(libfdt), types.ModuleType)

    def testBadFdt(self):
        """Check that a filename provided accidentally is not accepted"""
        with self.assertRaises(FdtException) as e:
            fdt = libfdt.Fdt('a string')
        self.assertEquals(e.exception.err, -libfdt.BADMAGIC)

    def testSubnodeOffset(self):
        """check that we can locate a subnode by name"""
        node1 = self.fdt.path_offset('/subnode@1')
        self.assertEquals(self.fdt.subnode_offset(0, 'subnode@1'), node1)

        with self.assertRaises(FdtException) as e:
            self.fdt.subnode_offset(0, 'missing')
        self.assertEquals(e.exception.err, -libfdt.NOTFOUND)

        node2 = self.fdt.path_offset('/subnode@1/subsubnode')
        self.assertEquals(self.fdt.subnode_offset(node1, 'subsubnode'), node2)

    def testPathOffset(self):
        """Check that we can find the offset of a node"""
        self.assertEquals(self.fdt.path_offset('/'), 0)
        self.assertTrue(self.fdt.path_offset('/subnode@1') > 0)
        with self.assertRaises(FdtException) as e:
            self.fdt.path_offset('/wibble')
        self.assertEquals(e.exception.err, -libfdt.NOTFOUND)
        self.assertEquals(self.fdt.path_offset('/wibble', QUIET_NOTFOUND),
                          -libfdt.NOTFOUND)

    def testPropertyOffset(self):
        """Walk through all the properties in the root node"""
        offset = self.fdt.first_property_offset(0)
        self.assertTrue(offset > 0)
        for i in range(5):
            next_offset = self.fdt.next_property_offset(offset)
            self.assertTrue(next_offset > offset)
            offset = next_offset
        self.assertEquals(self.fdt.next_property_offset(offset, QUIET_NOTFOUND),
                          -libfdt.NOTFOUND)

    def testPropertyOffsetExceptions(self):
        """Check that exceptions are raised as expected"""
        with self.assertRaises(FdtException) as e:
            self.fdt.first_property_offset(107)
        self.assertEquals(e.exception.err, -libfdt.BADOFFSET)

        # Quieten the NOTFOUND exception and check that a BADOFFSET
        # exception is still raised.
        with self.assertRaises(FdtException) as e:
            self.fdt.first_property_offset(107, QUIET_NOTFOUND)
        self.assertEquals(e.exception.err, -libfdt.BADOFFSET)
        with self.assertRaises(FdtException) as e:
            self.fdt.next_property_offset(107, QUIET_NOTFOUND)
        self.assertEquals(e.exception.err, -libfdt.BADOFFSET)

        # Check that NOTFOUND can be quietened.
        node = self.fdt.path_offset('/subnode@1/ss1')
        self.assertEquals(self.fdt.first_property_offset(node, QUIET_NOTFOUND),
                          -libfdt.NOTFOUND)
        with self.assertRaises(FdtException) as e:
            self.fdt.first_property_offset(node)
        self.assertEquals(e.exception.err, -libfdt.NOTFOUND)

    def testGetName(self):
        """Check that we can get the name of a node"""
        self.assertEquals(self.fdt.get_name(0), '')
        node = self.fdt.path_offset('/subnode@1/subsubnode')
        self.assertEquals(self.fdt.get_name(node), 'subsubnode')

        with self.assertRaises(FdtException) as e:
            self.fdt.get_name(-2)
        self.assertEquals(e.exception.err, -libfdt.BADOFFSET)

    def testGetPropertyByOffset(self):
        """Check that we can read the name and contents of a property"""
        root = 0
        poffset = self.fdt.first_property_offset(root)
        prop = self.fdt.get_property_by_offset(poffset)
        self.assertEquals(prop.name, 'compatible')
        self.assertEquals(prop.value, 'test_tree1\0')

        with self.assertRaises(FdtException) as e:
            self.fdt.get_property_by_offset(-2)
        self.assertEquals(e.exception.err, -libfdt.BADOFFSET)
        self.assertEquals(
                -libfdt.BADOFFSET,
                self.fdt.get_property_by_offset(-2, [libfdt.BADOFFSET]))

    def testGetProp(self):
        """Check that we can read the contents of a property by name"""
        root = self.fdt.path_offset('/')
        value = self.fdt.getprop(root, "compatible")
        self.assertEquals(value, 'test_tree1\0')
        self.assertEquals(-libfdt.NOTFOUND, self.fdt.getprop(root, 'missing',
                                                             QUIET_NOTFOUND))

        with self.assertRaises(FdtException) as e:
            self.fdt.getprop(root, 'missing')
        self.assertEquals(e.exception.err, -libfdt.NOTFOUND)

        node = self.fdt.path_offset('/subnode@1/subsubnode')
        value = self.fdt.getprop(node, "compatible")
        self.assertEquals(value, 'subsubnode1\0subsubnode\0')

    def testStrError(self):
        """Check that we can get an error string"""
        self.assertEquals(libfdt.strerror(-libfdt.NOTFOUND),
                          'FDT_ERR_NOTFOUND')

    def testFirstNextSubnodeOffset(self):
        """Check that we can walk through subnodes"""
        node_list = []
        node = self.fdt.first_subnode(0, QUIET_NOTFOUND)
        while node >= 0:
            node_list.append(self.fdt.get_name(node))
            node = self.fdt.next_subnode(node, QUIET_NOTFOUND)
        self.assertEquals(node_list, ['subnode@1', 'subnode@2'])

    def testFirstNextSubnodeOffsetExceptions(self):
        """Check except handling for first/next subnode functions"""
        node = self.fdt.path_offset('/subnode@1/subsubnode', QUIET_NOTFOUND)
        self.assertEquals(self.fdt.first_subnode(node, QUIET_NOTFOUND),
                          -libfdt.NOTFOUND)
        with self.assertRaises(FdtException) as e:
            self.fdt.first_subnode(node)
        self.assertEquals(e.exception.err, -libfdt.NOTFOUND)

        node = self.fdt.path_offset('/subnode@1/ss1', QUIET_NOTFOUND)
        self.assertEquals(self.fdt.next_subnode(node, QUIET_NOTFOUND),
                          -libfdt.NOTFOUND)
        with self.assertRaises(FdtException) as e:
            self.fdt.next_subnode(node)
        self.assertEquals(e.exception.err, -libfdt.NOTFOUND)

    def testDeleteProperty(self):
        """Test that we can delete a property"""
        node_name = '/subnode@1'
        self.assertEquals(self.GetPropList(node_name),
                          ['compatible', 'reg', 'prop-int'])
        node = self.fdt.path_offset('/%s' % node_name)
        self.assertEquals(self.fdt.delprop(node, 'reg'), 0)
        self.assertEquals(self.GetPropList(node_name),
                          ['compatible', 'prop-int'])

    def testHeader(self):
        """Test that we can access the header values"""
        self.assertEquals(self.fdt.totalsize(), len(self.fdt._fdt))
        self.assertEquals(self.fdt.off_dt_struct(), 88)

    def testPack(self):
        """Test that we can pack the tree after deleting something"""
        orig_size = self.fdt.totalsize()
        node = self.fdt.path_offset('/subnode@2', QUIET_NOTFOUND)
        self.assertEquals(self.fdt.delprop(node, 'prop-int'), 0)
        self.assertEquals(orig_size, self.fdt.totalsize())
        self.assertEquals(self.fdt.pack(), 0)
        self.assertTrue(self.fdt.totalsize() < orig_size)

    def testBadPropertyOffset(self):
        """Test that bad property offsets are detected"""
        with self.assertRaises(FdtException) as e:
            self.fdt.get_property_by_offset(13)
        self.assertEquals(e.exception.err, -libfdt.BADOFFSET)
        with self.assertRaises(FdtException) as e:
            self.fdt.first_property_offset(3)
        self.assertEquals(e.exception.err, -libfdt.BADOFFSET)
        with self.assertRaises(FdtException) as e:
            self.fdt.next_property_offset(3)
        self.assertEquals(e.exception.err, -libfdt.BADOFFSET)

    def testBadPathOffset(self):
        """Test that bad path names are detected"""
        with self.assertRaisesRegexp(FdtException, get_err(libfdt.BADPATH)):
            self.fdt.path_offset('not-present')

    def testQuietAll(self):
        """Check that exceptions can be masked by QUIET_ALL"""
        self.assertEquals(-libfdt.NOTFOUND,
                          self.fdt.path_offset('/missing', QUIET_ALL))
        self.assertEquals(-libfdt.BADOFFSET,
                          self.fdt.get_property_by_offset(13, QUIET_ALL))
        self.assertEquals(-libfdt.BADPATH,
                          self.fdt.path_offset('missing', QUIET_ALL))

    def testIntegers(self):
        """Check that integers can be passed and returned"""
        self.assertEquals(0, libfdt.fdt_get_phandle(self.fdt._fdt, 0))
        node2 = self.fdt.path_offset('/subnode@2')
        self.assertEquals(0x2000, libfdt.fdt_get_phandle(self.fdt._fdt, node2))

    def testGetPhandle(self):
        """Test for the get_phandle() method"""
        self.assertEquals(0, self.fdt.get_phandle(0))
        node2 = self.fdt.path_offset('/subnode@2')
        self.assertEquals(0x2000, self.fdt.get_phandle(node2))

    def testParentOffset(self):
        """Test for the parent_offset() method"""
        self.assertEquals(-libfdt.NOTFOUND,
                          self.fdt.parent_offset(0, QUIET_NOTFOUND))
        with self.assertRaises(FdtException) as e:
            self.fdt.parent_offset(0)
        self.assertEquals(e.exception.err, -libfdt.NOTFOUND)

        node1 = self.fdt.path_offset('/subnode@2')
        self.assertEquals(0, self.fdt.parent_offset(node1))
        node2 = self.fdt.path_offset('/subnode@2/subsubnode@0')
        self.assertEquals(node1, self.fdt.parent_offset(node2))

    def testNodeOffsetByPhandle(self):
        """Test for the node_offset_by_phandle() method"""
        self.assertEquals(-libfdt.NOTFOUND,
                          self.fdt.node_offset_by_phandle(1, QUIET_NOTFOUND))
        node1 = self.fdt.path_offset('/subnode@2')
        self.assertEquals(node1, self.fdt.node_offset_by_phandle(0x2000))
        node2 = self.fdt.path_offset('/subnode@2/subsubnode@0')
        self.assertEquals(node2, self.fdt.node_offset_by_phandle(0x2001))


if __name__ == "__main__":
    unittest.main()