Gather the setup of the initial OpenBSD MBR partition into one

location within MBR_init(), ensuring that MBR_init() creates an
OpenBSD MBR partition only when there is space for it.

No functional change.

diff --git a/sbin/fdisk/mbr.c b/sbin/fdisk/mbr.c
index 2166162..251bf8d 100644 (file)
--- a/sbin/fdisk/mbr.c
+++ b/sbin/fdisk/mbr.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: mbr.c,v 1.109 2021/11/20 18:35:55 krw Exp $   */
+/*     $OpenBSD: mbr.c,v 1.110 2021/11/20 21:35:52 krw Exp $   */
 
 /*
  * Copyright (c) 1997 Tobias Weingartner
@@ -66,11 +66,7 @@ MBR_init(struct mbr *mbr)
        memcpy(&dp, &default_dmbr.dmbr_parts[0], sizeof(dp));
        PRT_parse(&dp, 0, 0, &bootprt);
 
-       if (bootprt.prt_flag != DOSACTIVE)
-               obsdprt.prt_flag = DOSACTIVE;
-
        /* Reserve first track, or first cyl, if possible. */
-       obsdprt.prt_id = DOSPTYP_OPENBSD;
        if (disk.dk_heads > 1 || disk.dk_cylinders > 1)
                obsdprt.prt_bs = disk.dk_sectors;
        else
@@ -79,7 +75,6 @@ MBR_init(struct mbr *mbr)
 #if defined(__powerpc__) || defined(__mips__)
        /* Now fix up for the MS-DOS boot partition on PowerPC/MIPS. */
        bootprt.prt_flag = DOSACTIVE;   /* Boot from dos part */
-       obsdprt.prt_flag = 0;
        if (bootprt.prt_ns > 0)
                obsdprt.prt_bs = bootprt.prt_bs + bootprt.prt_ns;
        if (obsdprt.prt_bs % spc != 0)
@@ -96,10 +91,18 @@ MBR_init(struct mbr *mbr)
        while (daddr < DL_SECTOBLK(&dl, obsdprt.prt_bs))
                daddr *= 2;
        obsdprt.prt_bs = DL_BLKTOSEC(&dl, daddr);
-       obsdprt.prt_ns = disksz - obsdprt.prt_bs;
+
+       if (obsdprt.prt_bs >= disksz) {
+               memset(&obsdprt, 0, sizeof(obsdprt));
+       } else {
+               obsdprt.prt_ns = disksz - obsdprt.prt_bs;
+               obsdprt.prt_id = DOSPTYP_OPENBSD;
+               if (bootprt.prt_flag != DOSACTIVE)
+                       obsdprt.prt_flag = DOSACTIVE;
+               PRT_fix_CHS(&obsdprt);
+       }
 
        PRT_fix_CHS(&bootprt);
-       PRT_fix_CHS(&obsdprt);
 
        memset(mbr, 0, sizeof(*mbr));
        memcpy(mbr->mbr_code, default_dmbr.dmbr_boot, sizeof(mbr->mbr_code));