headers_install.pl: convert to headers_install.sh

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.

Same as last time except for minor tweak to deal with code review from
here: http://lkml.indiana.edu/hypermail/linux/kernel/1302.3/00078.html

(Note that this drops the "arch" argument, which isn't used. Kbuild
already points to the right input files on the command line.)

Signed-off-by: Rob Landley <rob@landley.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Josh Boyer <jwboyer@redhat.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: David Howells <dhowell@redhat.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>

3 files changed, 45 insertions, 65 deletions

diff --git a/scripts/Makefile.headersinst b/scripts/Makefile.headersinst
index 477d137c0557..182084d728c8 100644
--- a/scripts/Makefile.headersinst
+++ b/scripts/Makefile.headersinst
@@ -72,7 +72,7 @@ printdir = $(patsubst $(INSTALL_HDR_PATH)/%/,%,$(dir $@))
 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;                                                           \
@@ -98,7 +98,7 @@ __headersinst: $(subdirs) $(install-file)
 	@:
 
 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 $@)))
 	$(call if_changed,install)
diff --git a/scripts/headers_install.pl b/scripts/headers_install.pl
deleted file mode 100644
index 581ca99c96f2..000000000000
--- a/scripts/headers_install.pl
+++ /dev/null
@@ -1,63 +0,0 @@
-#!/usr/bin/perl -w
-#
-# headers_install prepare the listed header files for use in
-# user space and copy the files to their destination.
-#
-# Usage: headers_install.pl readdir installdir arch [files...]
-# installdir: dir to install the files to
-# arch:       current architecture
-#             arch is used to force a reinstallation when the arch
-#             changes because kbuild then detect a command line change.
-# files:      list of files to check
-#
-# Step in preparation for users space:
-# 1) Drop all use of compiler.h definitions
-# 2) Drop include of compiler.h
-# 3) Drop all sections defined out by __KERNEL__ (using unifdef)
-
-use strict;
-
-my ($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\s+_UAPI/#ifndef /;
-		$line =~ s/#define\s+_UAPI/#define /;
-		$line =~ s!#endif\s+/[*]\s*_UAPI!#endif /* !;
-		printf {$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;
diff --git a/scripts/headers_install.sh b/scripts/headers_install.sh
new file mode 100644
index 000000000000..643764f53ea7
--- /dev/null
+++ b/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(]|$)/\1__\2__\3/g' \
+		-e 's@#(ifndef|define|endif[ \t]*/[*])[ \t]*_UAPI@#\1 @' \
+		"$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