From 0777b3f0a366f58879e3d2c25dbc240a5a1d60ff Mon Sep 17 00:00:00 2001
From: kevans <kevans@FreeBSD.org>
Date: Wed, 20 Feb 2019 18:30:54 +0000
Subject: [PATCH] MFC r334412: userboot: Fix bad type-punning

Pass a struct devdesc to the format commands. Use proper type rather
than doing weird type-punning that happened to work because the size
was right. We copied a zfs devdesc into a disk_devdesc and then after
passing through a NULL pointer reinterpreted it as a
zfs_devdesc. Instead, pass the base devdesc around and 'upcase' when
we know the types are right.

This has the happy side effect of fixing a gcc warning about bad
type punning.
---
 stand/userboot/userboot/devicename.c | 10 +++++-----
 stand/userboot/userboot/main.c       | 17 +++++++++--------
 2 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/stand/userboot/userboot/devicename.c b/stand/userboot/userboot/devicename.c
index 06ec3948141..ede7ae947d4 100644
--- a/stand/userboot/userboot/devicename.c
+++ b/stand/userboot/userboot/devicename.c
@@ -175,30 +175,30 @@ userboot_parsedev(struct disk_devdesc **dev, const char *devspec, const char **p
 char *
 userboot_fmtdev(void *vdev)
 {
-    struct disk_devdesc	*dev = (struct disk_devdesc *)vdev;
+    struct devdesc	*dev = (struct devdesc *)vdev;
     static char		buf[128];	/* XXX device length constant? */
 
-    switch(dev->dd.d_dev->dv_type) {
+    switch(dev->d_dev->dv_type) {
     case DEVT_NONE:
 	strcpy(buf, "(no device)");
 	break;
 
     case DEVT_CD:
-	sprintf(buf, "%s%d:", dev->dd.d_dev->dv_name, dev->dd.d_unit);
+	sprintf(buf, "%s%d:", dev->d_dev->dv_name, dev->d_unit);
 	break;
 
     case DEVT_DISK:
 	return (disk_fmtdev(vdev));
 
     case DEVT_NET:
-	sprintf(buf, "%s%d:", dev->dd.d_dev->dv_name, dev->dd.d_unit);
+	sprintf(buf, "%s%d:", dev->d_dev->dv_name, dev->d_unit);
 	break;
 
     case DEVT_ZFS:
 #if defined(USERBOOT_ZFS_SUPPORT)
 	return (zfs_fmtdev(vdev));
 #else
-	sprintf(buf, "%s%d:", dev->dd.d_dev->dv_name, dev->dd.d_unit);
+	sprintf(buf, "%s%d:", dev->d_dev->dv_name, dev->d_unit);
 #endif
 	break;
     }
diff --git a/stand/userboot/userboot/main.c b/stand/userboot/userboot/main.c
index 0fcd9ac97bd..294951f88aa 100644
--- a/stand/userboot/userboot/main.c
+++ b/stand/userboot/userboot/main.c
@@ -154,19 +154,18 @@ static void
 extract_currdev(void)
 {
 	struct disk_devdesc dev;
-
-	//bzero(&dev, sizeof(dev));
-
+	struct devdesc *dd;
 #if defined(USERBOOT_ZFS_SUPPORT)
+	struct zfs_devdesc zdev;
+
 	if (userboot_zfs_found) {
-		struct zfs_devdesc zdev;
 	
 		/* Leave the pool/root guid's unassigned */
 		bzero(&zdev, sizeof(zdev));
 		zdev.dd.d_dev = &zfs_dev;
 		
-		dev = *(struct disk_devdesc *)&zdev;
-		init_zfs_bootenv(zfs_fmtdev(&dev));
+		init_zfs_bootenv(zfs_fmtdev(&zdev));
+		dd = &zdev.dd;
 	} else
 #endif
 
@@ -183,14 +182,16 @@ extract_currdev(void)
 			dev.d_slice = -1;
 			dev.d_partition = -1;
 		}
+		dd = &dev.dd;
 	} else {
 		dev.dd.d_dev = &host_dev;
 		dev.dd.d_unit = 0;
+		dd = &dev.dd;
 	}
 
-	env_setenv("currdev", EV_VOLATILE, userboot_fmtdev(&dev),
+	env_setenv("currdev", EV_VOLATILE, userboot_fmtdev(dd),
 	    userboot_setcurrdev, env_nounset);
-	env_setenv("loaddev", EV_VOLATILE, userboot_fmtdev(&dev),
+	env_setenv("loaddev", EV_VOLATILE, userboot_fmtdev(dd),
 	    env_noset, env_nounset);
 }
 
-- 
2.45.0