1 #!/usr/bin/env python3
2 # SPDX-License-Identifier: GPL-2.0
3 #
4 # diffconfig - a tool to compare .config files.
5 #
6 # originally written in 2006 by Matt Mackall
7 # (at least, this was in his bloatwatch source code)
8 # last worked on 2008 by Tim Bird
9 #
10
11 import sys, os
12
13 def usage():
14 print("""Usage: diffconfig [-h] [-m] [<config1> <config2>]
15
16 Diffconfig is a simple utility for comparing two .config files.
17 Using standard diff to compare .config files often includes extraneous and
18 distracting information. This utility produces sorted output with only the
19 changes in configuration values between the two files.
20
21 Added and removed items are shown with a leading plus or minus, respectively.
22 Changed items show the old and new values on a single line.
23
24 If -m is specified, then output will be in "merge" style, which has the
25 changed and new values in kernel config option format.
26
27 If no config files are specified, .config and .config.old are used.
28
29 Example usage:
30 $ diffconfig .config config-with-some-changes
31 -EXT2_FS_XATTR 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
40 def 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
51 def 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
68 def show_diff():
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 "KBUILD_OUTPUT" in os.environ:
89 build_dir = os.environ["KBUILD_OUTPUT"]+"/"
90 configa_filename = build_dir + ".config.old"
91 configb_filename = build_dir + ".config"
92 else:
93 configa_filename = sys.argv[1]
94 configb_filename = sys.argv[2]
95
96 try:
97 a = readconfig(open(configa_filename))
98 b = readconfig(open(configb_filename))
99 except (IOError):
100 e = sys.exc_info()[1]
101 print("I/O error[%s]: %s\n" % (e.args[0],e.args[1]))
102 usage()
103
104 # print items in a but not b (accumulate, sort and print)
105 old = []
106 for config in a:
107 if config not in b:
108 old.append(config)
109 old.sort()
110 for config in old:
111 print_config("-", config, a[config], None)
112 del a[config]
113
114 # print items that changed (accumulate, sort, and print)
115 changed = []
116 for config in a:
117 if a[config] != b[config]:
118 changed.append(config)
119 else:
120 del b[config]
121 changed.sort()
122 for config in changed:
123 print_config("->", config, a[config], b[config])
124 del b[config]
125
126 # now print items in b but not in a
127 # (items from b that were in a were removed above)
128 new = sorted(b.keys())
129 for config in new:
130 print_config("+", config, None, b[config])
131
132 def main():
133 try:
134 show_diff()
135 except BrokenPipeError:
136 # Python flushes standard streams on exit; redirect remaining output
137 # to devnull to avoid another BrokenPipeError at shutdown
138 devnull = os.open(os.devnull, os.O_WRONLY)
139 os.dup2(devnull, sys.stdout.fileno())
140 sys.exit(1) # Python exits with error code 1 on EPIPE
141
142
143 if __name__ == '__main__':
144 main()
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