Add a script that checks the file offsets for boot(8)'s .text and .data

sections match up with their LMAs. This is necessary since biosboot does
not perform relocation.

Discussed with deraadt@

2 files changed, 71 insertions, 2 deletions

diff --git a/sys/arch/i386/stand/boot/Makefile b/sys/arch/i386/stand/boot/Makefile
index fc7fff893bb..33d0f43ceea 100644
--- a/sys/arch/i386/stand/boot/Makefile
+++ b/sys/arch/i386/stand/boot/Makefile
@@ -1,4 +1,4 @@
-#	$OpenBSD: Makefile,v 1.41 2012/10/12 14:00:02 jsing Exp $
+#	$OpenBSD: Makefile,v 1.42 2012/10/12 14:58:26 jsing Exp $
 
 .include "${.CURDIR}/../Makefile.inc"
 
@@ -53,8 +53,12 @@ SRCS+=	adler32.c crc32.c inflate.c inftrees.c
 boot.bin: boot
 	objcopy -v -O binary ${PROG} boot.bin
 
+CLEANFILES+= ${PROG}.new
+
 ${PROG}: $(OBJS)
-	$(LD) $(LDFLAGS) -o ${PROG} $(OBJS)
+	$(LD) $(LDFLAGS) -o ${PROG}.new $(OBJS)
+	@perl ${.CURDIR}/check-boot.pl ${PROG}.new
+	@mv ${PROG}.new ${PROG}
 	@$(SIZE) ${PROG}
 
 .else
diff --git a/sys/arch/i386/stand/boot/check-boot.pl b/sys/arch/i386/stand/boot/check-boot.pl
new file mode 100644
index 00000000000..77a3d3f899f
--- /dev/null
+++ b/sys/arch/i386/stand/boot/check-boot.pl
@@ -0,0 +1,65 @@
+#!/usr/bin/perl -w
+
+#
+# Copyright (c) 2012 Joel Sing <jsing@openbsd.org>
+#
+# Permission to use, copy, modify, and distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+#
+
+#
+# Ensure that the file offset for .text and .data aligns with the LMA. If they
+# do not match boot(8) will fail since biosboot(8) does not perform relocation.
+#
+
+$LINKBASE = 0x40000;
+
+if (scalar(@ARGV) != 1) {
+	print "Usage: check-boot.pl boot\n";
+	exit(2);
+}
+
+$boot = shift @ARGV;
+if (! -f $boot) {
+	print "No such file - $boot\n";
+	exit(2);
+}
+
+$valid = 1;
+$sections = 0;
+
+open(OBJDUMP, "/usr/bin/objdump -h $boot |") || die "Failed to run objdump";
+while (<OBJDUMP>) {
+	@section = split / +/, $_;
+	next if scalar(@section) < 7;
+	if ($section[2] =~ /(\.(text|data))/) {
+		$name = $1;
+		$lma = hex($section[5]);
+		$fileoff = hex($section[6]);
+		$offset = $lma - $LINKBASE;
+		$sections++;
+
+		if ($fileoff != $offset) {
+			printf "$name has incorrect file offset " .
+			    "0x%x (should be 0x%x)\n", $fileoff, $offset;
+			$valid = 0;
+		}
+	}
+}
+close(OBJDUMP);
+
+if ($sections != 2) {
+	print "Failed to find .text or .data section!\n";
+	exit(1);
+}
+
+exit(1) if ! $valid;