Subject: [PATCH] Replace scripts/headers_install.pl with a shell script.

From: Rob Landley <rob@landley.net>

Remove perl from make headers_install by replacing a perl script (doing
a simple regex search and replace) with a smaller, faster, simpler,
POSIX-2008 shell script implementation.  The new shell script is a single
for loop calling sed and piping its output through unifdef to produce the
target file.

Previous submission: Tuesday Jan 18, 2011
Message-ID: <4D359E5C.1070002@parallels.com>

Signed-off-by: Rob Landley <rob@landley.net>
---

 scripts/Makefile.headersinst |    6 +--
 scripts/headers_install.pl   |   58 ---------------------------------
 scripts/headers_install.sh   |   43 ++++++++++++++++++++++++
 3 files changed, 46 insertions(+), 61 deletions(-)

diff -ruN linux-3.1/scripts/headers_install.sh linux-2.6.30/scripts/headers_install.sh
--- linux-3.1/scripts/headers_install.sh
+++ linux/scripts/headers_install.sh
@@ -0,0 +1,43 @@
+#!/bin/sh
+
+if [ $# -lt 1 ]
+then
+	echo "Usage: headers_install.sh OUTDIR [FILES...]
+	echo
+	echo "Prepares kernel header files for use by user space, by removing"
+	echo "all compiler.h definitions and #includes, removing any"
+	echo "#ifdef __KERNEL__ sections, and putting __underscores__ around"
+	echo "asm/inline/volatile keywords."
+	echo
+	echo "OUTDIR: directory to write each userspace header FILE to."
+	echo "FILES:  list of header files to operate on."
+
+	exit 1
+fi
+
+# Grab arguments
+
+OUTDIR="$1"
+shift
+
+# Iterate through files listed on command line
+
+FILE=
+trap 'rm -f "$OUTDIR/$FILE" "$OUTDIR/$FILE.sed"' EXIT
+for i in "$@"
+do
+	FILE="$(basename "$i")"
+	sed -r \
+		-e 's/([ \t(])(__user|__force|__iomem)[ \t]/\1/g' \
+		-e 's/__attribute_const__([ \t]|$)/\1/g' \
+		-e 's@^#include <linux/compiler.h>@@' \
+		-e 's/(^|[^a-zA-Z0-9])__packed([^a-zA-Z0-9_]|$)/\1__attribute__((packed))\2/g' \
+		-e 's/(^|[ \t])(inline|asm|volatile)([ \t(]|$)/\1__\2__\3/g' \
+		-e 's@#(ifndef|define|endif /[*]) _UAPI@#\1 @' \
+		"$i" > "$OUTDIR/$FILE.sed" || exit 1
+	scripts/unifdef -U__KERNEL__ -D__EXPORTED_HEADERS__ "$OUTDIR/$FILE.sed" \
+		> "$OUTDIR/$FILE"
+	[ $? -gt 1 ] && exit 1
+	rm -f "$OUTDIR/$FILE.sed"
+done
+trap - EXIT
diff -ruN linux-3.1/scripts/Makefile.headersinst
--- linux-3.1/scripts/Makefile.headersinst
+++ linux/scripts/Makefile.headersinst
@@ -55,7 +55,7 @@
 quiet_cmd_install = INSTALL $(printdir) ($(words $(all-files))\
                             file$(if $(word 2, $(all-files)),s))
       cmd_install = \
-        $(PERL) $< $(installdir) $(SRCARCH) $(input-files); \
+        $(CONFIG_SHELL) $< $(installdir) $(input-files); \
         for F in $(wrapper-files); do                                   \
                 echo "\#include <asm-generic/$$F>" > $(installdir)/$$F;    \
         done;                                                           \
@@ -83,7 +83,7 @@
 	@:
 
 targets += $(install-file)
-$(install-file): scripts/headers_install.pl $(input-files) FORCE
+$(install-file): scripts/headers_install.sh $(input-files) FORCE
 	$(if $(unwanted),$(call cmd,remove),)
 	$(if $(wildcard $(dir $@)),,$(shell mkdir -p $(dir $@)))
 	$(call if_changed,install)
--- a/scripts/headers_install.pl
+++ /dev/null
@@ -1,63 +0,0 @@
-#!/usr/bin/perl -w
-#
-# headers_install prepare the listed header files for use in
-# user space and copy the files to their destination.
-#
-# Usage: headers_install.pl readdir installdir arch [files...]
-# installdir: dir to install the files to
-# arch:       current architecture
-#             arch is used to force a reinstallation when the arch
-#             changes because kbuild then detect a command line change.
-# files:      list of files to check
-#
-# Step in preparation for users space:
-# 1) Drop all use of compiler.h definitions
-# 2) Drop include of compiler.h
-# 3) Drop all sections defined out by __KERNEL__ (using unifdef)
-
-use strict;
-
-my ($installdir, $arch, @files) = @ARGV;
-
-my $unifdef = "scripts/unifdef -U__KERNEL__ -D__EXPORTED_HEADERS__";
-
-foreach my $filename (@files) {
-	my $file = $filename;
-	$file =~ s!^.*/!!;
-
-	my $tmpfile = "$installdir/$file.tmp";
-
-	open(my $in, '<', $filename)
-	    or die "$filename: $!\n";
-	open(my $out, '>', $tmpfile)
-	    or die "$tmpfile: $!\n";
-	while (my $line = <$in>) {
-		$line =~ s/([\s(])__user\s/$1/g;
-		$line =~ s/([\s(])__force\s/$1/g;
-		$line =~ s/([\s(])__iomem\s/$1/g;
-		$line =~ s/\s__attribute_const__\s/ /g;
-		$line =~ s/\s__attribute_const__$//g;
-		$line =~ s/\b__packed\b/__attribute__((packed))/g;
-		$line =~ s/^#include <linux\/compiler.h>//;
-		$line =~ s/(^|\s)(inline)\b/$1__$2__/g;
-		$line =~ s/(^|\s)(asm)\b(\s|[(]|$)/$1__$2__$3/g;
-		$line =~ s/(^|\s|[(])(volatile)\b(\s|[(]|$)/$1__$2__$3/g;
-		$line =~ s/#ifndef _UAPI/#ifndef /;
-		$line =~ s/#define _UAPI/#define /;
-		$line =~ s!#endif /[*] _UAPI!#endif /* !;
-		printf {$out} "%s", $line;
-	}
-	close $out;
-	close $in;
-
-	system $unifdef . " $tmpfile > $installdir/$file";
-	# unifdef will exit 0 on success, and will exit 1 when the
-	# file was processed successfully but no changes were made,
-	# so abort only when it's higher than that.
-	my $e = $? >> 8;
-	if ($e > 1) {
-		die "$tmpfile: $!\n";
-	}
-	unlink $tmpfile;
-}
-exit 0;