Add -p option to "prepare" (newfs) a filesystem that will be used for

the bootloader.  This is a no-op on architectures where such a filesystem
isn't needed.

ok krw@, deraadt@

14 files changed, 394 insertions, 78 deletions

diff --git a/usr.sbin/installboot/armv7_installboot.c b/usr.sbin/installboot/armv7_installboot.c
index 0c589f1cd0b..8251deb6388 100644
--- a/usr.sbin/installboot/armv7_installboot.c
+++ b/usr.sbin/installboot/armv7_installboot.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: armv7_installboot.c,v 1.10 2021/06/27 04:52:01 jsg Exp $	*/
+/*	$OpenBSD: armv7_installboot.c,v 1.11 2021/07/20 14:51:56 kettenis Exp $	*/
 /*	$NetBSD: installboot.c,v 1.5 1995/11/17 23:23:50 gwr Exp $ */
 
 /*
@@ -55,6 +55,7 @@
 
 #include "installboot.h"
 
+static int	create_filesystem(struct disklabel *, char);
 static void	write_filesystem(struct disklabel *, char);
 static int	findgptefisys(int, struct disklabel *);
 static int	findmbrfat(int, struct disklabel *);
@@ -70,6 +71,35 @@ md_loadboot(void)
 }
 
 void
+md_prepareboot(int devfd, char *dev)
+{
+	struct disklabel dl;
+	int part;
+
+	/* Get and check disklabel. */
+	if (ioctl(devfd, DIOCGDINFO, &dl) == -1)
+		err(1, "disklabel: %s", dev);
+	if (dl.d_magic != DISKMAGIC)
+		errx(1, "bad disklabel magic=0x%08x", dl.d_magic);
+
+	/* Warn on unknown disklabel types. */
+	if (dl.d_type == 0)
+		warnx("disklabel type unknown");
+
+	part = findgptefisys(devfd, &dl);
+	if (part != -1) {
+		create_filesystem(&dl, (char)part);
+		return;
+	}
+
+	part = findmbrfat(devfd, &dl);
+	if (part != -1) {
+		create_filesystem(&dl, (char)part);
+		return;
+	}
+}
+
+void
 md_installboot(int devfd, char *dev)
 {
 	struct disklabel dl;
@@ -98,12 +128,51 @@ md_installboot(int devfd, char *dev)
 	}
 }
 
+static int
+create_filesystem(struct disklabel *dl, char part)
+{
+	static char *newfsfmt ="/sbin/newfs_msdos %s >/dev/null";
+	struct msdosfs_args args;
+	char cmd[60];
+	int rslt;
+
+	/* Mount <duid>.<part> as msdos filesystem. */
+	memset(&args, 0, sizeof(args));
+	rslt = asprintf(&args.fspec,
+	    "%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx.%c",
+            dl->d_uid[0], dl->d_uid[1], dl->d_uid[2], dl->d_uid[3],
+            dl->d_uid[4], dl->d_uid[5], dl->d_uid[6], dl->d_uid[7],
+	    part);
+	if (rslt == -1) {
+		warn("bad special device");
+		return rslt;
+	}
+
+	rslt = snprintf(cmd, sizeof(cmd), newfsfmt, args.fspec);
+	if (rslt >= sizeof(cmd)) {
+		warnx("can't build newfs command");
+		rslt = -1;
+		return rslt;
+	}
+
+	if (verbose)
+		fprintf(stderr, "%s %s\n",
+		    (nowrite ? "would newfs" : "newfsing"), args.fspec);
+	if (!nowrite) {
+		rslt = system(cmd);
+		if (rslt == -1) {
+			warn("system('%s') failed", cmd);
+			return rslt;
+		}
+	}
+
+	return 0;
+}
 
 static void
 write_filesystem(struct disklabel *dl, char part)
 {
 	static char *fsckfmt = "/sbin/fsck_msdos %s >/dev/null";
-	static char *newfsfmt ="/sbin/newfs_msdos %s >/dev/null";
 	struct msdosfs_args args;
 	char cmd[60];
 	char dst[PATH_MAX];
@@ -150,18 +219,9 @@ write_filesystem(struct disklabel *dl, char part)
 		}
 		if (mount(MOUNT_MSDOS, dst, 0, &args) == -1) {
 			/* Try newfs'ing it. */
-			rslt = snprintf(cmd, sizeof(cmd), newfsfmt,
-			    args.fspec);
-			if (rslt >= sizeof(cmd)) {
-				warnx("can't build newfs command");
-				rslt = -1;
+			rslt = create_filesystem(dl, part);
+			if (rslt == -1)
 				goto rmdir;
-			}
-			rslt = system(cmd);
-			if (rslt == -1) {
-				warn("system('%s') failed", cmd);
-				goto rmdir;
-			}
 			rslt = mount(MOUNT_MSDOS, dst, 0, &args);
 			if (rslt == -1) {
 				warn("unable to mount EFI System partition");
diff --git a/usr.sbin/installboot/hppa_installboot.c b/usr.sbin/installboot/hppa_installboot.c
index d0fa5461ce9..4fccfc1f3e0 100644
--- a/usr.sbin/installboot/hppa_installboot.c
+++ b/usr.sbin/installboot/hppa_installboot.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: hppa_installboot.c,v 1.3 2018/09/01 16:55:29 krw Exp $	*/
+/*	$OpenBSD: hppa_installboot.c,v 1.4 2021/07/20 14:51:56 kettenis Exp $	*/
 
 /*
  * Copyright (c) 2013 Joel Sing <jsing@openbsd.org>
@@ -31,6 +31,11 @@ md_loadboot(void)
 }
 
 void
+md_prepareboot(int devfd, char *dev)
+{
+}
+
+void
 md_installboot(int devfd, char *dev)
 {
 	bootstrap(devfd, dev, stage1);
diff --git a/usr.sbin/installboot/i386_installboot.c b/usr.sbin/installboot/i386_installboot.c
index 4a15560a097..c3bf4eaaa44 100644
--- a/usr.sbin/installboot/i386_installboot.c
+++ b/usr.sbin/installboot/i386_installboot.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: i386_installboot.c,v 1.39 2021/06/02 22:44:27 krw Exp $	*/
+/*	$OpenBSD: i386_installboot.c,v 1.40 2021/07/20 14:51:56 kettenis Exp $	*/
 /*	$NetBSD: installboot.c,v 1.5 1995/11/17 23:23:50 gwr Exp $ */
 
 /*
@@ -129,6 +129,29 @@ md_loadboot(void)
 }
 
 void
+md_prepareboot(int devfd, char *dev)
+{
+	struct disklabel dl;
+	int part;
+
+	/* Get and check disklabel. */
+	if (ioctl(devfd, DIOCGDINFO, &dl) == -1)
+		err(1, "disklabel: %s", dev);
+	if (dl.d_magic != DISKMAGIC)
+		errx(1, "bad disklabel magic=0x%08x", dl.d_magic);
+
+	/* Warn on unknown disklabel types. */
+	if (dl.d_type == 0)
+		warnx("disklabel type unknown");
+
+	part = findgptefisys(devfd, &dl);
+	if (part != -1) {
+		create_filesystem(&dl, (char)part);
+		return;
+	}
+}
+
+void
 md_installboot(int devfd, char *dev)
 {
 	struct disklabel dl;
@@ -221,11 +244,51 @@ write_bootblocks(int devfd, char *dev, struct disklabel *dl)
 	}
 }
 
+int
+create_filesystem(struct disklabel *dl, char part)
+{
+	static char *newfsfmt ="/sbin/newfs_msdos %s >/dev/null";
+	struct msdosfs_args args;
+	char cmd[60];
+	int rslt;
+
+	/* Mount <duid>.<part> as msdos filesystem. */
+	memset(&args, 0, sizeof(args));
+	rslt = asprintf(&args.fspec,
+	    "%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx.%c",
+            dl->d_uid[0], dl->d_uid[1], dl->d_uid[2], dl->d_uid[3],
+            dl->d_uid[4], dl->d_uid[5], dl->d_uid[6], dl->d_uid[7],
+	    part);
+	if (rslt == -1) {
+		warn("bad special device");
+		return rslt;
+	}
+
+	rslt = snprintf(cmd, sizeof(cmd), newfsfmt, args.fspec);
+	if (rslt >= sizeof(cmd)) {
+		warnx("can't build newfs command");
+		rslt = -1;
+		return rslt;
+	}
+
+	if (verbose)
+		fprintf(stderr, "%s %s\n",
+		    (nowrite ? "would newfs" : "newfsing"), args.fspec);
+	if (!nowrite) {
+		rslt = system(cmd);
+		if (rslt == -1) {
+			warn("system('%s') failed", cmd);
+			return rslt;
+		}
+	}
+
+	return 0;
+}
+
 void
 write_filesystem(struct disklabel *dl, char part)
 {
 	static char *fsckfmt = "/sbin/fsck_msdos %s >/dev/null";
-	static char *newfsfmt ="/sbin/newfs_msdos %s >/dev/null";
 	struct msdosfs_args args;
 	char cmd[60];
 	char dst[PATH_MAX];
@@ -272,18 +335,9 @@ write_filesystem(struct disklabel *dl, char part)
 		}
 		if (mount(MOUNT_MSDOS, dst, 0, &args) == -1) {
 			/* Try newfs'ing it. */
-			rslt = snprintf(cmd, sizeof(cmd), newfsfmt,
-			    args.fspec);
-			if (rslt >= sizeof(cmd)) {
-				warnx("can't build newfs command");
-				rslt = -1;
+			rslt = create_filesystem(dl, part);
+			if (rslt == -1)
 				goto rmdir;
-			}
-			rslt = system(cmd);
-			if (rslt == -1) {
-				warn("system('%s') failed", cmd);
-				goto rmdir;
-			}
 			rslt = mount(MOUNT_MSDOS, dst, 0, &args);
 			if (rslt == -1) {
 				warn("unable to mount EFI System partition");
diff --git a/usr.sbin/installboot/i386_installboot.h b/usr.sbin/installboot/i386_installboot.h
index 0f75c057d06..2df9176fee2 100644
--- a/usr.sbin/installboot/i386_installboot.h
+++ b/usr.sbin/installboot/i386_installboot.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: i386_installboot.h,v 1.6 2020/06/27 15:35:29 deraadt Exp $	*/
+/*	$OpenBSD: i386_installboot.h,v 1.7 2021/07/20 14:51:56 kettenis Exp $	*/
 /*
  * Copyright (c) 2011 Joel Sing <jsing@openbsd.org>
  * Copyright (c) 2003 Tom Cosgrove <tom.cosgrove@arches-consulting.com>
@@ -55,4 +55,5 @@ void	pbr_set_symbols(char *, char *, struct sym_data *);
 void	sym_set_value(struct sym_data *, char *, u_int32_t);
 void	write_bootblocks(int, char *, struct disklabel *);
 int	findgptefisys(int, struct disklabel *);
+int	create_filesystem(struct disklabel *, char);
 void	write_filesystem(struct disklabel *, char);
diff --git a/usr.sbin/installboot/installboot.8 b/usr.sbin/installboot/installboot.8
index 125cdb04d30..3429ffcfbf9 100644
--- a/usr.sbin/installboot/installboot.8
+++ b/usr.sbin/installboot/installboot.8
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: installboot.8,v 1.4 2014/01/18 18:14:21 jmc Exp $
+.\"	$OpenBSD: installboot.8,v 1.5 2021/07/20 14:51:56 kettenis Exp $
 .\"
 .\" Copyright (c) 2013, 2014 Joel Sing
 .\"
@@ -14,7 +14,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: January 18 2014 $
+.Dd $Mdocdate: July 20 2021 $
 .Dt INSTALLBOOT 8
 .Os
 .Sh NAME
@@ -22,7 +22,7 @@
 .Nd install bootstrap on a disk
 .Sh SYNOPSIS
 .Nm installboot
-.Op Fl nv
+.Op Fl npv
 .Op Fl r Ar root
 .Ar disk
 .Op Ar stage1 Op Ar stage2
@@ -39,6 +39,10 @@ The options are as follows:
 .Bl -tag -width Ds
 .It Fl n
 Perform a dry run - do not actually write any bootstrap to the disk.
+.It Fl p
+Prepare filesystem.
+This will create a new filesystem on the partition reserved for the
+boot loader on architectures that require one.
 .It Fl r Ar root
 Specify the mount point of the
 .Ar root
diff --git a/usr.sbin/installboot/installboot.c b/usr.sbin/installboot/installboot.c
index cd293c02c56..6f79d397886 100644
--- a/usr.sbin/installboot/installboot.c
+++ b/usr.sbin/installboot/installboot.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: installboot.c,v 1.13 2019/10/29 17:41:45 deraadt Exp $	*/
+/*	$OpenBSD: installboot.c,v 1.14 2021/07/20 14:51:56 kettenis Exp $	*/
 
 /*
  * Copyright (c) 2012, 2013 Joel Sing <jsing@openbsd.org>
@@ -27,6 +27,7 @@
 #include "installboot.h"
 
 int	nowrite;
+int	prepare;
 int	stages;
 int	verbose;
 
@@ -39,7 +40,7 @@ usage(void)
 {
 	extern char *__progname;
 
-	fprintf(stderr, "usage: %s [-nv] [-r root] disk [stage1%s]\n",
+	fprintf(stderr, "usage: %s [-npv] [-r root] disk [stage1%s]\n",
 	    __progname, (stages >= 2) ? " [stage2]" : "");
 
 	exit(1);
@@ -53,11 +54,14 @@ main(int argc, char **argv)
 
 	md_init();
 
-	while ((opt = getopt(argc, argv, "nr:v")) != -1) {
+	while ((opt = getopt(argc, argv, "npr:v")) != -1) {
 		switch (opt) {
 		case 'n':
 			nowrite = 1;
 			break;
+		case 'p':
+			prepare = 1;
+			break;
 		case 'r':
 			root = strdup(optarg);
 			if (root == NULL)
@@ -115,6 +119,11 @@ main(int argc, char **argv)
 
 	md_loadboot();
 
+	if (prepare) {
+		md_prepareboot(devfd, realdev);
+		return 0;
+	}
+
 #ifdef SOFTRAID
 	sr_installboot(devfd, dev);
 #else
diff --git a/usr.sbin/installboot/installboot.h b/usr.sbin/installboot/installboot.h
index 74488f9e9b4..54d362c7ab4 100644
--- a/usr.sbin/installboot/installboot.h
+++ b/usr.sbin/installboot/installboot.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: installboot.h,v 1.12 2020/06/08 19:17:12 kn Exp $	*/
+/*	$OpenBSD: installboot.h,v 1.13 2021/07/20 14:51:56 kettenis Exp $	*/
 /*
  * Copyright (c) 2012, 2013 Joel Sing <jsing@openbsd.org>
  *
@@ -37,6 +37,7 @@ u_int32_t crc32(const u_char *, const u_int32_t);
 
 void	md_init(void);
 void	md_loadboot(void);
+void	md_prepareboot(int, char *);
 void	md_installboot(int, char *);
 
 #ifdef SOFTRAID
diff --git a/usr.sbin/installboot/landisk_installboot.c b/usr.sbin/installboot/landisk_installboot.c
index f8c8d91c462..b61a536139c 100644
--- a/usr.sbin/installboot/landisk_installboot.c
+++ b/usr.sbin/installboot/landisk_installboot.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: landisk_installboot.c,v 1.9 2018/09/01 16:55:29 krw Exp $	*/
+/*	$OpenBSD: landisk_installboot.c,v 1.10 2021/07/20 14:51:56 kettenis Exp $	*/
 
 /*
  * Copyright (c) 2013 Joel Sing <jsing@openbsd.org>
@@ -39,6 +39,11 @@ md_loadboot(void)
 }
 
 void
+md_prepareboot(int devfd, char *dev)
+{
+}
+
+void
 md_installboot(int devfd, char *dev)
 {
 	/* XXX - is this necessary? */
diff --git a/usr.sbin/installboot/loongson_installboot.c b/usr.sbin/installboot/loongson_installboot.c
index 30994071ed0..639cc1001f5 100644
--- a/usr.sbin/installboot/loongson_installboot.c
+++ b/usr.sbin/installboot/loongson_installboot.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: loongson_installboot.c,v 1.3 2020/07/19 15:23:08 visa Exp $	*/
+/*	$OpenBSD: loongson_installboot.c,v 1.4 2021/07/20 14:51:56 kettenis Exp $	*/
 /*	$NetBSD: installboot.c,v 1.5 1995/11/17 23:23:50 gwr Exp $ */
 
 /*
@@ -67,6 +67,11 @@ md_loadboot(void)
 }
 
 void
+md_prepareboot(int devfd, char *dev)
+{
+}
+
+void
 md_installboot(int devfd, char *dev)
 {
 	struct disklabel dl;
diff --git a/usr.sbin/installboot/macppc_installboot.c b/usr.sbin/installboot/macppc_installboot.c
index 3afb3b66a3d..b3ee6534da5 100644
--- a/usr.sbin/installboot/macppc_installboot.c
+++ b/usr.sbin/installboot/macppc_installboot.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: macppc_installboot.c,v 1.3 2020/07/22 05:06:38 deraadt Exp $	*/
+/*	$OpenBSD: macppc_installboot.c,v 1.4 2021/07/20 14:51:56 kettenis Exp $	*/
 
 /*
  * Copyright (c) 2011 Joel Sing <jsing@openbsd.org>
@@ -53,6 +53,7 @@
 
 #include "installboot.h"
 
+static int	create_filesystem(struct disklabel *, char);
 static void	write_filesystem(struct disklabel *, char);
 static int	findmbrfat(int, struct disklabel *);
 
@@ -67,6 +68,29 @@ md_loadboot(void)
 }
 
 void
+md_prepareboot(int devfd, char *dev)
+{
+	struct disklabel dl;
+	int part;
+
+	/* Get and check disklabel. */
+	if (ioctl(devfd, DIOCGDINFO, &dl) == -1)
+		err(1, "disklabel: %s", dev);
+	if (dl.d_magic != DISKMAGIC)
+		errx(1, "bad disklabel magic=0x%08x", dl.d_magic);
+
+	/* Warn on unknown disklabel types. */
+	if (dl.d_type == 0)
+		warnx("disklabel type unknown");
+
+	part = findmbrfat(devfd, &dl);
+	if (part != -1) {
+		create_filesystem(&dl, (char)part);
+		return;
+	}
+}
+
+void
 md_installboot(int devfd, char *dev)
 {
 	struct disklabel dl;
@@ -89,12 +113,51 @@ md_installboot(int devfd, char *dev)
 	}
 }
 
+static int
+create_filesystem(struct disklabel *dl, char part)
+{
+	static char *newfsfmt ="/sbin/newfs_msdos %s >/dev/null";
+	struct msdosfs_args args;
+	char cmd[60];
+	int rslt;
+
+	/* Mount <duid>.<part> as msdos filesystem. */
+	memset(&args, 0, sizeof(args));
+	rslt = asprintf(&args.fspec,
+	    "%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx.%c",
+            dl->d_uid[0], dl->d_uid[1], dl->d_uid[2], dl->d_uid[3],
+            dl->d_uid[4], dl->d_uid[5], dl->d_uid[6], dl->d_uid[7],
+	    part);
+	if (rslt == -1) {
+		warn("bad special device");
+		return rslt;
+	}
+
+	rslt = snprintf(cmd, sizeof(cmd), newfsfmt, args.fspec);
+	if (rslt >= sizeof(cmd)) {
+		warnx("can't build newfs command");
+		rslt = -1;
+		return rslt;
+	}
+
+	if (verbose)
+		fprintf(stderr, "%s %s\n",
+		    (nowrite ? "would newfs" : "newfsing"), args.fspec);
+	if (!nowrite) {
+		rslt = system(cmd);
+		if (rslt == -1) {
+			warn("system('%s') failed", cmd);
+			return rslt;
+		}
+	}
+
+	return 0;
+}
 
 static void
 write_filesystem(struct disklabel *dl, char part)
 {
 	static char *fsckfmt = "/sbin/fsck_msdos %s >/dev/null";
-	static char *newfsfmt ="/sbin/newfs_msdos %s >/dev/null";
 	struct msdosfs_args args;
 	char cmd[60];
 	char dst[PATH_MAX];
@@ -141,18 +204,9 @@ write_filesystem(struct disklabel *dl, char part)
 		}
 		if (mount(MOUNT_MSDOS, dst, 0, &args) == -1) {
 			/* Try newfs'ing it. */
-			rslt = snprintf(cmd, sizeof(cmd), newfsfmt,
-			    args.fspec);
-			if (rslt >= sizeof(cmd)) {
-				warnx("can't build newfs command");
-				rslt = -1;
-				goto rmdir;
-			}
-			rslt = system(cmd);
-			if (rslt == -1) {
-				warn("system('%s') failed", cmd);
+			rslt = create_filesystem(dl, part);
+			if (rslt == -1)
 				goto rmdir;
-			}
 			rslt = mount(MOUNT_MSDOS, dst, 0, &args);
 			if (rslt == -1) {
 				warn("unable to mount MSDOS partition");
diff --git a/usr.sbin/installboot/octeon_installboot.c b/usr.sbin/installboot/octeon_installboot.c
index d9be070997d..c1dbf51256a 100644
--- a/usr.sbin/installboot/octeon_installboot.c
+++ b/usr.sbin/installboot/octeon_installboot.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: octeon_installboot.c,v 1.3 2020/07/22 05:06:38 deraadt Exp $	*/
+/*	$OpenBSD: octeon_installboot.c,v 1.4 2021/07/20 14:51:56 kettenis Exp $	*/
 
 /*
  * Copyright (c) 2011 Joel Sing <jsing@openbsd.org>
@@ -53,6 +53,7 @@
 
 #include "installboot.h"
 
+static int	create_filesystem(struct disklabel *, char);
 static void	write_filesystem(struct disklabel *, char);
 static int	findmbrfat(int, struct disklabel *);
 
@@ -67,6 +68,29 @@ md_loadboot(void)
 }
 
 void
+md_prepareboot(int devfd, char *dev)
+{
+	struct disklabel dl;
+	int part;
+
+	/* Get and check disklabel. */
+	if (ioctl(devfd, DIOCGDINFO, &dl) == -1)
+		err(1, "disklabel: %s", dev);
+	if (dl.d_magic != DISKMAGIC)
+		errx(1, "bad disklabel magic=0x%08x", dl.d_magic);
+
+	/* Warn on unknown disklabel types. */
+	if (dl.d_type == 0)
+		warnx("disklabel type unknown");
+
+	part = findmbrfat(devfd, &dl);
+	if (part != -1) {
+		create_filesystem(&dl, (char)part);
+		return;
+	}
+}
+
+void
 md_installboot(int devfd, char *dev)
 {
 	struct disklabel dl;
@@ -89,12 +113,51 @@ md_installboot(int devfd, char *dev)
 	}
 }
 
+static int
+create_filesystem(struct disklabel *dl, char part)
+{
+	static char *newfsfmt ="/sbin/newfs_msdos %s >/dev/null";
+	struct msdosfs_args args;
+	char cmd[60];
+	int rslt;
+
+	/* Mount <duid>.<part> as msdos filesystem. */
+	memset(&args, 0, sizeof(args));
+	rslt = asprintf(&args.fspec,
+	    "%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx.%c",
+            dl->d_uid[0], dl->d_uid[1], dl->d_uid[2], dl->d_uid[3],
+            dl->d_uid[4], dl->d_uid[5], dl->d_uid[6], dl->d_uid[7],
+	    part);
+	if (rslt == -1) {
+		warn("bad special device");
+		return rslt;
+	}
+
+	rslt = snprintf(cmd, sizeof(cmd), newfsfmt, args.fspec);
+	if (rslt >= sizeof(cmd)) {
+		warnx("can't build newfs command");
+		rslt = -1;
+		return rslt;
+	}
+
+	if (verbose)
+		fprintf(stderr, "%s %s\n",
+		    (nowrite ? "would newfs" : "newfsing"), args.fspec);
+	if (!nowrite) {
+		rslt = system(cmd);
+		if (rslt == -1) {
+			warn("system('%s') failed", cmd);
+			return rslt;
+		}
+	}
+
+	return 0;
+}
 
 static void
 write_filesystem(struct disklabel *dl, char part)
 {
 	static char *fsckfmt = "/sbin/fsck_msdos %s >/dev/null";
-	static char *newfsfmt ="/sbin/newfs_msdos %s >/dev/null";
 	struct msdosfs_args args;
 	char cmd[60];
 	char dst[PATH_MAX];
@@ -141,18 +204,9 @@ write_filesystem(struct disklabel *dl, char part)
 		}
 		if (mount(MOUNT_MSDOS, dst, 0, &args) == -1) {
 			/* Try newfs'ing it. */
-			rslt = snprintf(cmd, sizeof(cmd), newfsfmt,
-			    args.fspec);
-			if (rslt >= sizeof(cmd)) {
-				warnx("can't build newfs command");
-				rslt = -1;
-				goto rmdir;
-			}
-			rslt = system(cmd);
-			if (rslt == -1) {
-				warn("system('%s') failed", cmd);
+			rslt = create_filesystem(dl, part);
+			if (rslt == -1)
 				goto rmdir;
-			}
 			rslt = mount(MOUNT_MSDOS, dst, 0, &args);
 			if (rslt == -1) {
 				warn("unable to mount MSDOS partition");
diff --git a/usr.sbin/installboot/powerpc64_installboot.c b/usr.sbin/installboot/powerpc64_installboot.c
index 351015934b1..0cd05835dc6 100644
--- a/usr.sbin/installboot/powerpc64_installboot.c
+++ b/usr.sbin/installboot/powerpc64_installboot.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: powerpc64_installboot.c,v 1.2 2020/07/18 15:28:38 deraadt Exp $	*/
+/*	$OpenBSD: powerpc64_installboot.c,v 1.3 2021/07/20 14:51:56 kettenis Exp $	*/
 
 /*
  * Copyright (c) 2011 Joel Sing <jsing@openbsd.org>
@@ -53,6 +53,7 @@
 
 #include "installboot.h"
 
+static int	create_filesystem(struct disklabel *, char);
 static void	write_filesystem(struct disklabel *, char);
 static int	findmbrfat(int, struct disklabel *);
 
@@ -69,6 +70,29 @@ md_loadboot(void)
 }
 
 void
+md_prepareboot(int devfd, char *dev)
+{
+	struct disklabel dl;
+	int part;
+
+	/* Get and check disklabel. */
+	if (ioctl(devfd, DIOCGDINFO, &dl) == -1)
+		err(1, "disklabel: %s", dev);
+	if (dl.d_magic != DISKMAGIC)
+		errx(1, "bad disklabel magic=0x%08x", dl.d_magic);
+
+	/* Warn on unknown disklabel types. */
+	if (dl.d_type == 0)
+		warnx("disklabel type unknown");
+
+	part = findmbrfat(devfd, &dl);
+	if (part != -1) {
+		create_filesystem(&dl, (char)part);
+		return;
+	}
+}
+
+void
 md_installboot(int devfd, char *dev)
 {
 	struct disklabel dl;
@@ -96,12 +120,51 @@ md_installboot(int devfd, char *dev)
 	}
 }
 
+static int
+create_filesystem(struct disklabel *dl, char part)
+{
+	static char *newfsfmt ="/sbin/newfs_msdos %s >/dev/null";
+	struct msdosfs_args args;
+	char cmd[60];
+	int rslt;
+
+	/* Mount <duid>.<part> as msdos filesystem. */
+	memset(&args, 0, sizeof(args));
+	rslt = asprintf(&args.fspec,
+	    "%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx.%c",
+            dl->d_uid[0], dl->d_uid[1], dl->d_uid[2], dl->d_uid[3],
+            dl->d_uid[4], dl->d_uid[5], dl->d_uid[6], dl->d_uid[7],
+	    part);
+	if (rslt == -1) {
+		warn("bad special device");
+		return rslt;
+	}
+
+	rslt = snprintf(cmd, sizeof(cmd), newfsfmt, args.fspec);
+	if (rslt >= sizeof(cmd)) {
+		warnx("can't build newfs command");
+		rslt = -1;
+		return rslt;
+	}
+
+	if (verbose)
+		fprintf(stderr, "%s %s\n",
+		    (nowrite ? "would newfs" : "newfsing"), args.fspec);
+	if (!nowrite) {
+		rslt = system(cmd);
+		if (rslt == -1) {
+			warn("system('%s') failed", cmd);
+			return rslt;
+		}
+	}
+
+	return 0;
+}
 
 static void
 write_filesystem(struct disklabel *dl, char part)
 {
 	static char *fsckfmt = "/sbin/fsck_msdos %s >/dev/null";
-	static char *newfsfmt ="/sbin/newfs_msdos %s >/dev/null";
 	struct msdosfs_args args;
 	char cmd[60];
 	char dir[PATH_MAX];
@@ -149,18 +212,9 @@ write_filesystem(struct disklabel *dl, char part)
 		}
 		if (mount(MOUNT_MSDOS, dir, 0, &args) == -1) {
 			/* Try newfs'ing it. */
-			rslt = snprintf(cmd, sizeof(cmd), newfsfmt,
-			    args.fspec);
-			if (rslt >= sizeof(cmd)) {
-				warnx("can't build newfs command");
-				rslt = -1;
+			rslt = create_filesystem(dl, part);
+			if (rslt == -1)
 				goto rmdir;
-			}
-			rslt = system(cmd);
-			if (rslt == -1) {
-				warn("system('%s') failed", cmd);
-				goto rmdir;
-			}
 			rslt = mount(MOUNT_MSDOS, dir, 0, &args);
 			if (rslt == -1) {
 				warn("unable to mount MSDOS partition");
diff --git a/usr.sbin/installboot/sparc64_installboot.c b/usr.sbin/installboot/sparc64_installboot.c
index bef2079a8af..3fb61efbf6b 100644
--- a/usr.sbin/installboot/sparc64_installboot.c
+++ b/usr.sbin/installboot/sparc64_installboot.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sparc64_installboot.c,v 1.8 2019/06/28 13:32:48 deraadt Exp $	*/
+/*	$OpenBSD: sparc64_installboot.c,v 1.9 2021/07/20 14:51:56 kettenis Exp $	*/
 
 /*
  * Copyright (c) 2012, 2013 Joel Sing <jsing@openbsd.org>
@@ -90,6 +90,11 @@ md_loadboot(void)
 }
 
 void
+md_prepareboot(int devfd, char *dev)
+{
+}
+
+void
 md_installboot(int devfd, char *dev)
 {
 	/* XXX - is this necessary? */
diff --git a/usr.sbin/installboot/stubs.c b/usr.sbin/installboot/stubs.c
index ced93a1daf8..9517512de9f 100644
--- a/usr.sbin/installboot/stubs.c
+++ b/usr.sbin/installboot/stubs.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: stubs.c,v 1.4 2015/10/15 04:41:10 deraadt Exp $	*/
+/*	$OpenBSD: stubs.c,v 1.5 2021/07/20 14:51:56 kettenis Exp $	*/
 
 /*
  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
@@ -32,6 +32,11 @@ md_loadboot(void)
 }
 
 void
+md_prepareboot(int devfd, char *dev)
+{
+}
+
+void
 md_installboot(int devfd, char *dev)
 {
 }