From: krw <krw@openbsd.org>
Date: Wed, 21 May 2014 15:55:19 +0000 (+0000)
Subject: Fix 'fdisk -u', a.k.a. MBR_pcopy(), on sparc64 and possibly others.
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=3dbb6cec788340c5ebe82921a5ab5a6e7ffe325d;p=openbsd

Fix 'fdisk -u', a.k.a. MBR_pcopy(), on sparc64 and possibly others.

gcc's built-in/in-lined memcpy() can't copy elements of a struct
dos_partiton array from inside the __packed struct dos_mbr into an
'unpacked' local variable. But copying the whole array works fine. Be
consistant and use the same idiom in both places the partition table
is parsed.

Leave the landisk workaround/hack in place until it can be confirmed
it is no longer needed.

ok martynas@ after many alternatives crashed and burned.
---

diff --git a/sbin/fdisk/mbr.c b/sbin/fdisk/mbr.c
index 7b0af1eb1e3..825b896deb6 100644
--- a/sbin/fdisk/mbr.c
+++ b/sbin/fdisk/mbr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mbr.c,v 1.39 2014/03/31 19:50:52 krw Exp $	*/
+/*	$OpenBSD: mbr.c,v 1.40 2014/05/21 15:55:19 krw Exp $	*/
 
 /*
  * Copyright (c) 1997 Tobias Weingartner
@@ -111,7 +111,7 @@ void
 MBR_parse(struct disk *disk, struct dos_mbr *dos_mbr, off_t offset,
     off_t reloff, struct mbr *mbr)
 {
-	struct dos_partition dos_partition;
+	struct dos_partition dos_parts[NDOSPART];
 	int i;
 
 	memcpy(mbr->code, dos_mbr->dmbr_boot, sizeof(mbr->code));
@@ -119,12 +119,10 @@ MBR_parse(struct disk *disk, struct dos_mbr *dos_mbr, off_t offset,
 	mbr->reloffset = reloff;
 	mbr->signature = letoh16(dos_mbr->dmbr_sign);
 
-	for (i = 0; i < NDOSPART; i++) {
-		memcpy(&dos_partition, &dos_mbr->dmbr_parts[i],
-		    sizeof(dos_partition));
-		PRT_parse(disk, &dos_partition, offset, reloff,
-		    &mbr->part[i]);
-	}
+	memcpy(dos_parts, dos_mbr->dmbr_parts, sizeof(dos_parts));
+
+	for (i = 0; i < NDOSPART; i++)
+		PRT_parse(disk, &dos_parts[i], offset, reloff, &mbr->part[i]);
 }
 
 void
@@ -246,6 +244,7 @@ MBR_pcopy(struct disk *disk, struct mbr *mbr)
 {
 	int i, fd, error;
 	struct dos_mbr dos_mbr;
+	struct dos_partition dos_parts[NDOSPART];
 
 	fd = DISK_open(disk->name, O_RDONLY);
 	error = MBR_read(fd, 0, &dos_mbr);
@@ -254,6 +253,8 @@ MBR_pcopy(struct disk *disk, struct mbr *mbr)
 	if (error == -1)
 		return;
 
+	memcpy(dos_parts, dos_mbr.dmbr_parts, sizeof(dos_parts));
+
 	for (i = 0; i < NDOSPART; i++)
-		PRT_parse(disk, &dos_mbr.dmbr_parts[i], 0, 0, &mbr->part[i]);
+		PRT_parse(disk, &dos_parts[i], 0, 0, &mbr->part[i]);
 }