xref: /linux/scripts/diffconfig (revision bcefe12eff5dca6fdfa94ed85e5bee66380d5cd9) 
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-EXT2_FS_XIP  n
32 CRAMFS  n -> y
33 EXT2_FS  y -> n
34 LOG_BUF_SHIFT  14 -> 16
35 PRINTK_TIME  n -> y
36"""
37    sys.exit(0)
38
39# returns a dictionary of name/value pairs for config items in the file
40def readconfig(config_file):
41    d = {}
42    for line in config_file:
43        line = line[:-1]
44        if line[:7] == "CONFIG_":
45            name, val = line[7:].split("=", 1)
46            d[name] = val
47        if line[-11:] == " is not set":
48            d[line[9:-11]] = "n"
49    return d
50
51def print_config(op, config, value, new_value):
52    global merge_style
53
54    if merge_style:
55        if new_value:
56            if new_value=="n":
57                print "# CONFIG_%s is not set" % config
58            else:
59                print "CONFIG_%s=%s" % (config, new_value)
60    else:
61        if op=="-":
62            print "-%s %s" % (config, value)
63        elif op=="+":
64            print "+%s %s" % (config, new_value)
65        else:
66            print " %s %s -> %s" % (config, value, new_value)
67
68def main():
69    global merge_style
70
71    # parse command line args
72    if ("-h" in sys.argv or "--help" in sys.argv):
73	usage()
74
75    merge_style = 0
76    if "-m" in sys.argv:
77        merge_style = 1
78        sys.argv.remove("-m")
79
80    argc = len(sys.argv)
81    if not (argc==1 or argc == 3):
82        print "Error: incorrect number of arguments or unrecognized option"
83        usage()
84
85    if argc == 1:
86        # if no filenames given, assume .config and .config.old
87        build_dir=""
88        if os.environ.has_key("KBUILD_OUTPUT"):
89            build_dir = os.environ["KBUILD_OUTPUT"]+"/"
90
91        configa_filename = build_dir + ".config.old"
92        configb_filename = build_dir + ".config"
93    else:
94        configa_filename = sys.argv[1]
95        configb_filename = sys.argv[2]
96
97    a = readconfig(file(configa_filename))
98    b = readconfig(file(configb_filename))
99
100    # print items in a but not b (accumulate, sort and print)
101    old = []
102    for config in a:
103        if config not in b:
104            old.append(config)
105    old.sort()
106    for config in old:
107        print_config("-", config, a[config], None)
108        del a[config]
109
110    # print items that changed (accumulate, sort, and print)
111    changed = []
112    for config in a:
113        if a[config] != b[config]:
114            changed.append(config)
115        else:
116            del b[config]
117    changed.sort()
118    for config in changed:
119        print_config("->", config, a[config], b[config])
120        del b[config]
121
122    # now print items in b but not in a
123    # (items from b that were in a were removed above)
124    new = b.keys()
125    new.sort()
126    for config in new:
127        print_config("+", config, None, b[config])
128
129main()
130