From 27ec9b9d1dabc862cc0432307340fa19205a9b86 Mon Sep 17 00:00:00 2001
From: pooka <pooka@NetBSD.org>
Date: Tue, 22 Feb 2011 15:42:15 +0000
Subject: [PATCH] Add support for a byteswapped disklabel so that I can mount
 NetBSD/sparc anita images on my i386.

---
 lib/libukfs/ukfs.c               | 18 ++++++++++---
 lib/libukfs/ukfs_disklabel.c     | 46 +++++++++++++++++++++++++-------
 lib/libukfs/ukfs_int_disklabel.h |  7 ++---
 3 files changed, 54 insertions(+), 17 deletions(-)

diff --git a/lib/libukfs/ukfs.c b/lib/libukfs/ukfs.c
index e52ac82dde65..f8612b1af3d8 100644
--- a/lib/libukfs/ukfs.c
+++ b/lib/libukfs/ukfs.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: ukfs.c,v 1.56 2011/01/02 13:01:45 pooka Exp $	*/
+/*	$NetBSD: ukfs.c,v 1.57 2011/02/22 15:42:15 pooka Exp $	*/
 
 /*
  * Copyright (c) 2007, 2008, 2009  Antti Kantee.  All Rights Reserved.
@@ -246,9 +246,11 @@ ukfs_part_probe(char *devpath, struct ukfs_part **partp)
 		    *(MAGICADJ_DISKLABEL(p,0)) < 'a' + UKFS_MAXPARTITIONS) {
 			struct ukfs__disklabel dl;
 			struct ukfs__partition *pp;
+			int imswapped;
 			char buf[65536];
 			char labelchar = *(MAGICADJ_DISKLABEL(p,0));
 			int partition = labelchar - 'a';
+			uint32_t poffset, psize;
 
 			*p = '\0';
 			devfd = open(devpath, O_RDONLY);
@@ -263,7 +265,8 @@ ukfs_part_probe(char *devpath, struct ukfs_part **partp)
 				goto out;
 			}
 
-			if (ukfs__disklabel_scan(&dl, buf, sizeof(buf)) != 0) {
+			if (ukfs__disklabel_scan(&dl, &imswapped,
+			    buf, sizeof(buf)) != 0) {
 				error = ENOENT;
 				goto out;
 			}
@@ -276,8 +279,15 @@ ukfs_part_probe(char *devpath, struct ukfs_part **partp)
 			pp = &dl.d_partitions[partition];
 			part->part_type = UKFS_PART_DISKLABEL;
 			part->part_labelchar = labelchar;
-			part->part_devoff = pp->p_offset << DEV_BSHIFT;
-			part->part_devsize = pp->p_size << DEV_BSHIFT;
+			if (imswapped) {
+				poffset = bswap32(pp->p_offset);
+				psize = bswap32(pp->p_size);
+			} else {
+				poffset = pp->p_offset;
+				psize = pp->p_size;
+			}
+			part->part_devoff = poffset << DEV_BSHIFT;
+			part->part_devsize = psize << DEV_BSHIFT;
 		} else {
 			error = EINVAL;
 		}
diff --git a/lib/libukfs/ukfs_disklabel.c b/lib/libukfs/ukfs_disklabel.c
index 73ac061663ec..ff7e0d7dd5ea 100644
--- a/lib/libukfs/ukfs_disklabel.c
+++ b/lib/libukfs/ukfs_disklabel.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: ukfs_disklabel.c,v 1.2 2009/12/03 14:23:49 pooka Exp $	*/
+/*	$NetBSD: ukfs_disklabel.c,v 1.3 2011/02/22 15:42:15 pooka Exp $	*/
 
 /*
  * Local copies of libutil disklabel routines.  This uncouples libukfs
@@ -50,27 +50,42 @@
 #define SCAN_INCR	4
 
 int
-ukfs__disklabel_scan(struct ukfs__disklabel *lp, char *buf, size_t buflen)
+ukfs__disklabel_scan(struct ukfs__disklabel *lp, int *isswapped,
+	char *buf, size_t buflen)
 {
-	size_t	i;
+	size_t i;
+	int imswapped;
+	uint16_t npart;
 
 	/* scan for the correct magic numbers. */
 
 	for (i=0; i <= buflen - sizeof(*lp); i += SCAN_INCR) {
 		memcpy(lp, buf + i, sizeof(*lp));
 		if (lp->d_magic == UKFS_DISKMAGIC &&
-		    lp->d_magic2 == UKFS_DISKMAGIC)
+		    lp->d_magic2 == UKFS_DISKMAGIC) {
+			imswapped = 0;
 			goto sanity;
+		}
+		if (lp->d_magic == bswap32(UKFS_DISKMAGIC) &&
+		    lp->d_magic2 == bswap32(UKFS_DISKMAGIC)) {
+			imswapped = 1;
+			goto sanity;
+		}
 	}
 
 	return 1;
 
 sanity:
+	if (imswapped)
+		npart = bswap16(lp->d_npartitions);
+	else
+		npart = lp->d_npartitions;
 	/* we've found something, let's sanity check it */
-	if (lp->d_npartitions > UKFS_MAXPARTITIONS
-	    || ukfs__disklabel_dkcksum(lp))
+	if (npart > UKFS_MAXPARTITIONS
+	    || ukfs__disklabel_dkcksum(lp, imswapped))
 		return 1;
 
+	*isswapped = imswapped;
 	return 0;
 }
 
@@ -110,15 +125,26 @@ sanity:
  */
 
 uint16_t
-ukfs__disklabel_dkcksum(struct ukfs__disklabel *lp)
+ukfs__disklabel_dkcksum(struct ukfs__disklabel *lp, int imswapped)
 {
 	uint16_t *start, *end;
 	uint16_t sum;
+	uint16_t npart;
+
+	if (imswapped)
+		npart = bswap16(lp->d_npartitions);
+	else
+		npart = lp->d_npartitions;
 
 	sum = 0;
 	start = (uint16_t *)(void *)lp;
-	end = (uint16_t *)(void *)&lp->d_partitions[lp->d_npartitions];
-	while (start < end)
-		sum ^= *start++;
+	end = (uint16_t *)(void *)&lp->d_partitions[npart];
+	while (start < end) {
+		if (imswapped)
+			sum ^= bswap16(*start);
+		else
+			sum ^= *start;
+		start++;
+	}
 	return (sum);
 }
diff --git a/lib/libukfs/ukfs_int_disklabel.h b/lib/libukfs/ukfs_int_disklabel.h
index 80760fb9c0c9..304f220ea352 100644
--- a/lib/libukfs/ukfs_int_disklabel.h
+++ b/lib/libukfs/ukfs_int_disklabel.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: ukfs_int_disklabel.h,v 1.2 2009/12/03 14:23:49 pooka Exp $	*/
+/*	$NetBSD: ukfs_int_disklabel.h,v 1.3 2011/02/22 15:42:15 pooka Exp $	*/
 
 /*
  * Modified copy of disklabel.h so that ukfs doesn't have to depend
@@ -151,7 +151,8 @@ struct ukfs__disklabel {
 	} d_partitions[UKFS_MAXPARTITIONS];	/* actually may be more */
 };
 
-uint16_t        ukfs__disklabel_dkcksum(struct ukfs__disklabel *);
-int             ukfs__disklabel_scan(struct ukfs__disklabel *, char *, size_t);
+uint16_t        ukfs__disklabel_dkcksum(struct ukfs__disklabel *, int);
+int             ukfs__disklabel_scan(struct ukfs__disklabel *, int *,
+				     char *, size_t);
 
 #endif /* !LIB_UKFS_DISKLABEL_H_ */