Add a new mode to the scripted partition editor for variant disk names.

If the disk parameter "DEFAULT" is set in place of an actual device name,
or no disk is specified for the PARTITIONS parameter, the installer will
follow the logic used in the automatic-partitioning mode, in which it
will either provide a selection dialog for one of several disks if
several are present or automatically select it if there is only one. This
simplifies the creation of fully-automatic installation media for
hardware or VMs with varying disk names.

Suggested by:	Egoitz Aurrekoetxea <egoitz@sarenet.es>
MFC after:	3 weeks
Relnotes:	yes

(cherry picked from commit 5140034cc077c416690b4fdb79a96744fe0af0e6)

4 files changed, 27 insertions, 11 deletions

diff --git a/usr.sbin/bsdinstall/bsdinstall.8 b/usr.sbin/bsdinstall/bsdinstall.8
index 781660bf5ef1..ee23fb4cecc4 100644
--- a/usr.sbin/bsdinstall/bsdinstall.8
+++ b/usr.sbin/bsdinstall/bsdinstall.8
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd March 22, 2021
+.Dd March 26, 2021
 .Dt BSDINSTALL 8
 .Os
 .Sh NAME
@@ -158,7 +158,13 @@ Multiple disk setups are separated by semicolons.
 The
 .Ar disk
 argument specifies the disk on which to operate (which will be erased),
-while the
+or the special value
+.Em DEFAULT ,
+which will result in either a selection window (as in
+.Cm autopart )
+for the destination disk or, if there is only one possible disk, will
+automatically select it.
+The
 .Ar scheme
 argument specifies the
 .Xr gpart 8
@@ -208,6 +214,10 @@ A shorter invocation to use the default partitioning (as
 would have used) on the same disk:
 .Pp
 bsdinstall scriptedpart ada0
+.Pp
+or, even shorter:
+.Pp
+bsdinstall scriptedpart DEFAULT
 .It Cm mount
 Mounts the file systems previously configured by
 .Cm autopart ,
@@ -279,7 +289,9 @@ See
 of
 the
 .Sx TARGETS
-section for format details.
+section for format details. If this variable is unset, the installer will
+use the default partitioning as in
+.Cm autopart .
 Default: unset
 .It Ev BSDINSTALL_DISTDIR
 The directory in which the distribution files can be found (or to which they
@@ -468,7 +480,7 @@ the interpreter for the setup script.
 A typical bsdinstall script, using the default filesystem layout and the UFS
 filesystem, looks like this:
 .Bd -literal -offset indent
-PARTITIONS=ada0
+PARTITIONS=DEFAULT
 DISTRIBUTIONS="kernel.txz base.txz"
 
 #!/bin/sh
diff --git a/usr.sbin/bsdinstall/partedit/part_wizard.c b/usr.sbin/bsdinstall/partedit/part_wizard.c
index 3160e1f049ea..9f7158a4801e 100644
--- a/usr.sbin/bsdinstall/partedit/part_wizard.c
+++ b/usr.sbin/bsdinstall/partedit/part_wizard.c
@@ -44,7 +44,6 @@
 #define MIN_FREE_SPACE		(1024*1024*1024) /* 1 GB */
 #define SWAP_SIZE(available)	MIN(available/20, 4*1024*1024*1024LL)
 
-static char *boot_disk(struct gmesh *mesh);
 static char *wizard_partition(struct gmesh *mesh, const char *disk);
 
 int
@@ -65,7 +64,7 @@ startwizard:
 
 	dlg_put_backtitle();
 	error = geom_gettree(&mesh);
-	disk = boot_disk(&mesh);
+	disk = boot_disk_select(&mesh);
 	if (disk == NULL)
 		return (1);
 
@@ -91,8 +90,8 @@ startwizard:
 	return (0);
 }
 
-static char *
-boot_disk(struct gmesh *mesh)
+char *
+boot_disk_select(struct gmesh *mesh)
 {
 	struct gclass *classp;
 	struct gconfig *gc;
diff --git a/usr.sbin/bsdinstall/partedit/partedit.h b/usr.sbin/bsdinstall/partedit/partedit.h
index 1dccc653aea1..5c0405922d21 100644
--- a/usr.sbin/bsdinstall/partedit/partedit.h
+++ b/usr.sbin/bsdinstall/partedit/partedit.h
@@ -58,6 +58,7 @@ void delete_part_metadata(const char *name);
 
 int part_wizard(const char *fstype);
 int scripted_editor(int argc, const char **argv);
+char *boot_disk_select(struct gmesh *mesh);
 int wizard_makeparts(struct gmesh *mesh, const char *disk, const char *fstype,
     int interactive);
 
diff --git a/usr.sbin/bsdinstall/partedit/scripted.c b/usr.sbin/bsdinstall/partedit/scripted.c
index 57dcbca816a3..37ac6de131b5 100644
--- a/usr.sbin/bsdinstall/partedit/scripted.c
+++ b/usr.sbin/bsdinstall/partedit/scripted.c
@@ -183,10 +183,14 @@ int parse_disk_config(char *input)
 		}
 	} while (input != NULL && *input != 0);
 
-	if (disk != NULL)
-		return (part_config(disk, scheme, partconfig));
+	if (disk == NULL || strcmp(disk, "DEFAULT") == 0) {
+		struct gmesh mesh;
+		geom_gettree(&mesh);
+		disk = boot_disk_select(&mesh);
+		geom_deletetree(&mesh);
+	}
 
-	return (0);
+	return (part_config(disk, scheme, partconfig));
 }
 
 int