#!/usr/bin/env perl

  # SPDX-License-Identifier: GPL-2.0

  #
  # headers_check.pl execute a number of trivial consistency checks
  #

  # Usage: headers_check.pl dir arch [files...]

  # dir:   dir to look for included files
  # arch:  architecture
  # files: list of files to check
  #
  # The script reads the supplied files line by line and:
  #
  # 1) for each include statement it checks if the
  #    included file actually exists.
  #    Only include files located in asm* and linux* are checked.
  #    The rest are assumed to be system include files.
  #

  # 2) It is checked that prototypes does not use "extern"
  #

  # 3) Check for leaked CONFIG_ symbols

  use warnings;

  use strict;

  use File::Basename;

  
  my ($dir, $arch, @files) = @ARGV;
  
  my $ret = 0;
  my $line;
  my $lineno = 0;
  my $filename;
  
  foreach my $file (@files) {
  	$filename = $file;

  
  	open(my $fh, '<', $filename)
  		or die "$filename: $!
  ";

  	$lineno = 0;

  	while ($line = <$fh>) {

  		$lineno++;

  		&check_include();
  		&check_asm_types();
  		&check_sizetypes();

  		&check_declarations();

  		# Dropped for now. Too much noise &check_config();

  	}

  	close $fh;

  }
  exit $ret;
  
  sub check_include
  {
  	if ($line =~ m/^\s*#\s*include\s+<((asm|linux).*)>/) {
  		my $inc = $1;
  		my $found;
  		$found = stat($dir . "/" . $inc);
  		if (!$found) {
  			$inc =~ s#asm/#asm-$arch/#;
  			$found = stat($dir . "/" . $inc);
  		}
  		if (!$found) {
  			printf STDERR "$filename:$lineno: included file '$inc' is not exported
  ";
  			$ret = 1;
  		}
  	}
  }

  sub check_declarations

  {

  	# soundcard.h is what it is
  	if ($line =~ m/^void seqbuf_dump\(void\);/) {
  		return;
  	}

  	# drm headers are being C++ friendly
  	if ($line =~ m/^extern "C"/) {
  		return;
  	}

  	if ($line =~ m/^(\s*extern|unsigned|char|short|int|long|void)\b/) {

  		printf STDERR "$filename:$lineno: " .

  			      "userspace cannot reference function or " .
  			      "variable defined in the kernel
  ";

  	}
  }

  
  sub check_config
  {

  	if ($line =~ m/[^a-zA-Z0-9_]+CONFIG_([a-zA-Z0-9_]+)[^a-zA-Z0-9_]/) {

  		printf STDERR "$filename:$lineno: leaks CONFIG_$1 to userspace where it is not valid
  ";
  	}
  }

  my $linux_asm_types;

  sub check_asm_types

  {

  	if ($filename =~ /types.h|int-l64.h|int-ll64.h/o) {
  		return;
  	}

  	if ($lineno == 1) {
  		$linux_asm_types = 0;
  	} elsif ($linux_asm_types >= 1) {
  		return;
  	}
  	if ($line =~ m/^\s*#\s*include\s+<asm\/types.h>/) {
  		$linux_asm_types = 1;
  		printf STDERR "$filename:$lineno: " .
  		"include of <linux/types.h> is preferred over <asm/types.h>
  "
  		# Warn until headers are all fixed
  		#$ret = 1;
  	}
  }
  
  my $linux_types;

  my %import_stack = ();
  sub check_include_typesh
  {
  	my $path = $_[0];
  	my $import_path;
  
  	my $fh;
  	my @file_paths = ($path, $dir . "/" .  $path, dirname($filename) . "/" . $path);
  	for my $possible ( @file_paths ) {
  	    if (not $import_stack{$possible} and open($fh, '<', $possible)) {
  		$import_path = $possible;
  		$import_stack{$import_path} = 1;
  		last;
  	    }
  	}
  	if (eof $fh) {
  	    return;
  	}
  
  	my $line;
  	while ($line = <$fh>) {
  		if ($line =~ m/^\s*#\s*include\s+<linux\/types.h>/) {
  			$linux_types = 1;
  			last;
  		}
  		if (my $included = ($line =~ /^\s*#\s*include\s+[<"](\S+)[>"]/)[0]) {
  			check_include_typesh($included);
  		}
  	}
  	close $fh;
  	delete $import_stack{$import_path};
  }

  sub check_sizetypes
  {

  	if ($filename =~ /types.h|int-l64.h|int-ll64.h/o) {
  		return;
  	}

  	if ($lineno == 1) {
  		$linux_types = 0;
  	} elsif ($linux_types >= 1) {
  		return;
  	}
  	if ($line =~ m/^\s*#\s*include\s+<linux\/types.h>/) {
  		$linux_types = 1;
  		return;
  	}

  	if (my $included = ($line =~ /^\s*#\s*include\s+[<"](\S+)[>"]/)[0]) {
  		check_include_typesh($included);
  	}

  	if ($line =~ m/__[us](8|16|32|64)\b/) {
  		printf STDERR "$filename:$lineno: " .
  		              "found __[us]{8,16,32,64} type " .
  		              "without #include <linux/types.h>
  ";
  		$linux_types = 2;
  		# Warn until headers are all fixed
  		#$ret = 1;
  	}
  }