Compare or find diff for device tree files (dtb)

dtb-diff.py

#!/usr/bin/python

import sys
import fdt
import argparse


# Return root node for given dtb file
def get_root(dtb):
    try:
        with open(dtb, 'rb') as infile:
            fdt_object = fdt.parse_dtb(infile.read())
            root = fdt_object.get_node('/')
            return root
    except Exception as e:
        print(e)
        sys.exit(1)


# Get list of keys from list of objects
def keys(items):
    return [p.name for p in items]


# Find if a node is present in another node
def find_node(node, name):
    for n in keys(node.nodes):
        if n == name:
            return node.get_subnode(n)
        elif (args.ignore_names) and ('@' in n and '@' in name) and (n.split('@')[1] == name.split('@')[1]):
            return node.get_subnode(n)
    return None


# Compare two nodes and return newline padded string
def diff_nodes(node1, node2, depth=0):
    # Store generated dts
    dts1 = []
    dts2 = []

    # Spacers
    sp_header = "  " * depth
    sp_param = "  " * (depth+1)

    # Append header
    dts1.append("%s%s {\n" % (sp_header, node1.name))
    dts2.append("%s%s {\n" % (sp_header, node2.name))

    # Compare properties
    for p in node1.props:
        if p.name not in keys(node2.props):
            # Property is missing in node2
            dts1.append("%s%s" % (sp_param, p.to_dts()))
            dts2.append("\n")
        else:
            # Property exists in both nodes
            dts1.append("%s%s" % (sp_param, p.to_dts()))
            dts2.append("%s%s" %
                        (sp_param, node2.get_property(p.name).to_dts()))

    # Compare properties present in node2 but not in node1
    for p in node2.props:
        if p.name not in keys(node1.props):
            # Property is missing in node1
            dts1.append("\n")
            dts2.append("%s%s" % (sp_param, p.to_dts()))

    # Compare subnodes
    for n in node1.nodes:
        node = find_node(node2, n.name)
        if not node:
            # Subnode is missing in node2
            lines = n.to_dts().splitlines()
            for line in lines:
                dts1.append("%s%s\n" % (sp_param, line))
            dts2 += ["\n"] * len(lines)
        else:
            # Subnode exists in both nodes, recurse
            d1, d2 = diff_nodes(n, node, depth+1)
            dts1 += d1
            dts2 += d2

    # Compare subnodes present in node2 but not in node1
    for n in node2.nodes:
        node = find_node(node1, n.name)
        if not node:
            # Subnode is missing in node1
            lines = n.to_dts().splitlines()
            for line in lines:
                dts2.append("%s%s\n" % (sp_param, line))
            dts1 += ["\n"] * len(lines)

    # Append footer
    dts1.append("%s};\n" % (sp_header))
    dts2.append("%s};\n" % (sp_header))

    # Return dts strings
    return dts1, dts2


# Parse arguments
parser = argparse.ArgumentParser(
    description="Compare and print differences between two device trees")
parser.add_argument("dtb1", help="First device tree")
parser.add_argument("dtb2", help="Second device tree")
parser.add_argument("--ignore-names", action="store_true",
                    help="Ignore node names and match by unit address if exact match fails")
parser.add_argument("--column-width", action="store",
                    default=90, help="Width for output columns. Default: 90")
args = parser.parse_args()

# Read dtb files
root1 = get_root(args.dtb1)
root2 = get_root(args.dtb2)

# Compare nodes
out1, out2 = diff_nodes(root1, root2)

stats = {
    "common": 0,
    "unique1": 0,
    "unique2": 0,
    "changed": 0,
}

try:
    # Print output
    for i in range(len(out1)):
        # Compare lines
        if (out1[i] == out2[i]):
            # Lines are the same
            color = ""
            symbol = " "
            stats['common'] += 1
        elif (out2[i] == "\n"):
            # Line is missing in dtb2
            color = "\033[31m"
            symbol = "<"
            stats['unique1'] += 1
        elif (out1[i] == "\n"):
            # Line is missing in dtb1
            color = "\033[32m"
            symbol = ">"
            stats['unique2'] += 1
        else:
            # Lines are different
            color = "\033[36m"
            symbol = "|"
            stats["changed"] += 1

        # Print line
        print("{}{:{width}.{width}} {} {:{width}.{width}}\033[0m".format(
            color,
            out1[i].replace('\n', ''),
            symbol,
            out2[i].replace('\n', ''),
            width=args.column_width
        ))
    print("\nSummary:\nCommon Lines: {}\nChanged Lines: {}\nUnique to {}: {}\nUnique to {}: {}".format(
        stats['common'],
        stats['changed'],
        args.dtb1,
        stats['unique1'],
        args.dtb2,
        stats['unique2']
    ))
except BrokenPipeError:
    pass