From 3220ebed14aaea7b477b113f72b9978d855c8d59 Mon Sep 17 00:00:00 2001
From: krw <krw@openbsd.org>
Date: Sat, 11 Dec 2021 20:09:28 +0000
Subject: [PATCH] Start the default OpenBSD partition either immediately
 following any boot partition specified via '-b' or /usr/mdec/mbr; at the
 power of 2 block after the first track; or immediately following the MBR if
 there is only one track.

Mark any non-EFISYS boot partition created by -b as DOSACTIVE.
Suggested by kettenis@, better than a separate new option.

Brings -b behaviour into line with many uses of -e to create boot
partitions, allowing for the eventual elimination of said -e uses
in the creation of the various boot media and in the install
scripts.
---
 sbin/fdisk/fdisk.c |  4 +++-
 sbin/fdisk/mbr.c   | 26 +++++++++++++++-----------
 2 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/sbin/fdisk/fdisk.c b/sbin/fdisk/fdisk.c
index 854966a9233..4c50e1fbdf0 100644
--- a/sbin/fdisk/fdisk.c
+++ b/sbin/fdisk/fdisk.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: fdisk.c,v 1.140 2021/10/19 19:38:10 krw Exp $	*/
+/*	$OpenBSD: fdisk.c,v 1.141 2021/12/11 20:09:28 krw Exp $	*/
 
 /*
  * Copyright (c) 1997 Tobias Weingartner
@@ -79,6 +79,8 @@ main(int argc, char *argv[])
 			break;
 		case 'b':
 			parse_bootprt(optarg);
+			if (disk.dk_bootprt.prt_id != DOSPTYP_EFISYS)
+				disk.dk_bootprt.prt_flag = DOSACTIVE;
 			break;
 		case 'c':
 			disk.dk_cylinders = strtonum(optarg, 1, 262144, &errstr);
diff --git a/sbin/fdisk/mbr.c b/sbin/fdisk/mbr.c
index d25b0897bb7..ad11fa130c4 100644
--- a/sbin/fdisk/mbr.c
+++ b/sbin/fdisk/mbr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mbr.c,v 1.113 2021/12/07 14:58:32 krw Exp $	*/
+/*	$OpenBSD: mbr.c,v 1.114 2021/12/11 20:09:28 krw Exp $	*/
 
 /*
  * Copyright (c) 1997 Tobias Weingartner
@@ -67,18 +67,22 @@ MBR_init(struct mbr *mbr)
 		PRT_parse(&dp, 0, 0, &bootprt);
 	}
 
-	if (bootprt.prt_ns > 0)
+	if (bootprt.prt_ns > 0) {
+		/* Start OpenBSD partition immediately after bootprt. */
 		obsdprt.prt_bs = bootprt.prt_bs + bootprt.prt_ns;
-	else if (disk.dk_heads > 1 || disk.dk_cylinders > 1)
-		obsdprt.prt_bs = disk.dk_sectors;
-	else
+	} else if (disk.dk_heads > 1 || disk.dk_cylinders > 1) {
+		/*
+		 * Start OpenBSD partition on power of 2 block number
+		 * after the first track.
+		 */
+		daddr = 1;
+		while (daddr < DL_SECTOBLK(&dl, disk.dk_sectors))
+			daddr *= 2;
+		obsdprt.prt_bs = DL_BLKTOSEC(&dl, daddr);
+	} else {
+		/* Start OpenBSD partition immediately after MBR. */
 		obsdprt.prt_bs = 1;
-
-	/* Start OpenBSD MBR partition on a power of 2 block number. */
-	daddr = 1;
-	while (daddr < DL_SECTOBLK(&dl, obsdprt.prt_bs))
-		daddr *= 2;
-	obsdprt.prt_bs = DL_BLKTOSEC(&dl, daddr);
+	}
 
 	if (obsdprt.prt_bs >= disk.dk_size) {
 		memset(&obsdprt, 0, sizeof(obsdprt));
-- 
2.20.1