xref: /linux/usr/include/headers_check.pl (revision 2ddcf4962c1834a14340a1f50afafc3276c015bd) 
1#!/usr/bin/env perl
2# SPDX-License-Identifier: GPL-2.0
3#
4# headers_check.pl execute a number of trivial consistency checks
5#
6# Usage: headers_check.pl dir [files...]
7# dir:   dir to look for included files
8# files: list of files to check
9#
10# The script reads the supplied files line by line and:
11#
12# 1) for each include statement it checks if the
13#    included file actually exists.
14#    Only include files located in asm* and linux* are checked.
15#    The rest are assumed to be system include files.
16#
17# 2) It is checked that prototypes does not use "extern"
18#
19# 3) Check for leaked CONFIG_ symbols
20
21use warnings;
22use strict;
23use File::Basename;
24
25my ($dir, @files) = @ARGV;
26
27my $ret = 0;
28my $line;
29my $lineno = 0;
30my $filename;
31
32foreach my $file (@files) {
33	$filename = $file;
34
35	open(my $fh, '<', $filename)
36		or die "$filename: $!\n";
37	$lineno = 0;
38	while ($line = <$fh>) {
39		$lineno++;
40		&check_include();
41		&check_asm_types();
42		&check_declarations();
43		# Dropped for now. Too much noise &check_config();
44	}
45	close $fh;
46}
47exit $ret;
48
49sub check_include
50{
51	if ($line =~ m/^\s*#\s*include\s+<((asm|linux).*)>/) {
52		my $inc = $1;
53		my $found;
54		$found = stat($dir . "/" . $inc);
55		if (!$found) {
56			printf STDERR "$filename:$lineno: included file '$inc' is not exported\n";
57			$ret = 1;
58		}
59	}
60}
61
62sub check_declarations
63{
64	# soundcard.h is what it is
65	if ($line =~ m/^void seqbuf_dump\(void\);/) {
66		return;
67	}
68	# drm headers are being C++ friendly
69	if ($line =~ m/^extern "C"/) {
70		return;
71	}
72	if ($line =~ m/^(\s*extern|unsigned|char|short|int|long|void)\b/) {
73		printf STDERR "$filename:$lineno: " .
74			      "userspace cannot reference function or " .
75			      "variable defined in the kernel\n";
76		$ret = 1;
77	}
78}
79
80sub check_config
81{
82	if ($line =~ m/[^a-zA-Z0-9_]+CONFIG_([a-zA-Z0-9_]+)[^a-zA-Z0-9_]/) {
83		printf STDERR "$filename:$lineno: leaks CONFIG_$1 to userspace where it is not valid\n";
84	}
85}
86
87my $linux_asm_types;
88sub check_asm_types
89{
90	if ($filename =~ /types.h|int-l64.h|int-ll64.h/o) {
91		return;
92	}
93	if ($lineno == 1) {
94		$linux_asm_types = 0;
95	} elsif ($linux_asm_types >= 1) {
96		return;
97	}
98	if ($line =~ m/^\s*#\s*include\s+<asm\/types.h>/) {
99		$linux_asm_types = 1;
100		printf STDERR "$filename:$lineno: " .
101		"include of <linux/types.h> is preferred over <asm/types.h>\n";
102		$ret = 1;
103	}
104}
105