1#!/usr/bin/python
2#
3# diffconfig - a tool to compare .config files.
4#
5# originally written in 2006 by Matt Mackall
6#  (at least, this was in his bloatwatch source code)
7# last worked on 2008 by Tim Bird
8#
9
10import sys, os
11
12def usage():
13    print("""Usage: diffconfig [-h] [-m] [<config1> <config2>]
14
15Diffconfig is a simple utility for comparing two .config files.
16Using standard diff to compare .config files often includes extraneous and
17distracting information.  This utility produces sorted output with only the
18changes in configuration values between the two files.
19
20Added and removed items are shown with a leading plus or minus, respectively.
21Changed items show the old and new values on a single line.
22
23If -m is specified, then output will be in "merge" style, which has the
24changed and new values in kernel config option format.
25
26If no config files are specified, .config and .config.old are used.
27
28Example usage:
29 $ diffconfig .config config-with-some-changes
30-EXT2_FS_XATTR  n
31 CRAMFS  n -> y
32 EXT2_FS  y -> n
33 LOG_BUF_SHIFT  14 -> 16
34 PRINTK_TIME  n -> y
35""")
36    sys.exit(0)
37
38# returns a dictionary of name/value pairs for config items in the file
39def readconfig(config_file):
40    d = {}
41    for line in config_file:
42        line = line[:-1]
43        if line[:7] == "CONFIG_":
44            name, val = line[7:].split("=", 1)
45            d[name] = val
46        if line[-11:] == " is not set":
47            d[line[9:-11]] = "n"
48    return d
49
50def print_config(op, config, value, new_value):
51    global merge_style
52
53    if merge_style:
54        if new_value:
55            if new_value=="n":
56                print("# CONFIG_%s is not set" % config)
57            else:
58                print("CONFIG_%s=%s" % (config, new_value))
59    else:
60        if op=="-":
61            print("-%s %s" % (config, value))
62        elif op=="+":
63            print("+%s %s" % (config, new_value))
64        else:
65            print(" %s %s -> %s" % (config, value, new_value))
66
67def main():
68    global merge_style
69
70    # parse command line args
71    if ("-h" in sys.argv or "--help" in sys.argv):
72        usage()
73
74    merge_style = 0
75    if "-m" in sys.argv:
76        merge_style = 1
77        sys.argv.remove("-m")
78
79    argc = len(sys.argv)
80    if not (argc==1 or argc == 3):
81        print("Error: incorrect number of arguments or unrecognized option")
82        usage()
83
84    if argc == 1:
85        # if no filenames given, assume .config and .config.old
86        build_dir=""
87        if "KBUILD_OUTPUT" in os.environ:
88            build_dir = os.environ["KBUILD_OUTPUT"]+"/"
89        configa_filename = build_dir + ".config.old"
90        configb_filename = build_dir + ".config"
91    else:
92        configa_filename = sys.argv[1]
93        configb_filename = sys.argv[2]
94
95    try:
96        a = readconfig(open(configa_filename))
97        b = readconfig(open(configb_filename))
98    except (IOError):
99        e = sys.exc_info()[1]
100        print("I/O error[%s]: %s\n" % (e.args[0],e.args[1]))
101        usage()
102
103    # print items in a but not b (accumulate, sort and print)
104    old = []
105    for config in a:
106        if config not in b:
107            old.append(config)
108    old.sort()
109    for config in old:
110        print_config("-", config, a[config], None)
111        del a[config]
112
113    # print items that changed (accumulate, sort, and print)
114    changed = []
115    for config in a:
116        if a[config] != b[config]:
117            changed.append(config)
118        else:
119            del b[config]
120    changed.sort()
121    for config in changed:
122        print_config("->", config, a[config], b[config])
123        del b[config]
124
125    # now print items in b but not in a
126    # (items from b that were in a were removed above)
127    new = sorted(b.keys())
128    for config in new:
129        print_config("+", config, None, b[config])
130
131main()
132