Use nitems() of source and destination partition arrays

rather than assuming they are the same size. Zero
destination entries when no source partition available.

No intentional functional change.

diff --git a/sbin/fdisk/gpt.c b/sbin/fdisk/gpt.c
index 7f82960..bff1007 100644 (file)
--- a/sbin/fdisk/gpt.c
+++ b/sbin/fdisk/gpt.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: gpt.c,v 1.85 2023/03/04 23:09:15 krw Exp $    */
+/*     $OpenBSD: gpt.c,v 1.86 2023/03/06 13:24:40 krw Exp $    */
 /*
  * Copyright (c) 2015 Markus Muller <mmu@grummel.net>
  * Copyright (c) 2015 Kenneth R Westerback <krw@openbsd.org>
@@ -124,14 +124,16 @@ int
 protective_mbr(const struct mbr *mbr)
 {
        struct dos_partition    dp[NDOSPART], dos_partition;
-       int                     i;
+       unsigned int            i;
 
        if (mbr->mbr_lba_self != 0)
                return -1;
 
-       for (i = 0; i < NDOSPART; i++) {
-               PRT_make(&mbr->mbr_prt[i], mbr->mbr_lba_self,
-                   mbr->mbr_lba_firstembr, &dos_partition);
+       for (i = 0; i < nitems(dp); i++) {
+               memset(&dos_partition, 0, sizeof(dos_partition));
+               if (i < nitems(mbr->mbr_prt))
+                       PRT_make(&mbr->mbr_prt[i], mbr->mbr_lba_self,
+                           mbr->mbr_lba_firstembr, &dos_partition);
                memcpy(&dp[i], &dos_partition, sizeof(dp[i]));
        }
 

diff --git a/sbin/fdisk/mbr.c b/sbin/fdisk/mbr.c
index ef88ed4..b7aeea0 100644 (file)
--- a/sbin/fdisk/mbr.c
+++ b/sbin/fdisk/mbr.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: mbr.c,v 1.122 2023/03/04 21:22:51 krw Exp $   */
+/*     $OpenBSD: mbr.c,v 1.123 2023/03/06 13:24:40 krw Exp $   */
 
 /*
  * Copyright (c) 1997 Tobias Weingartner
@@ -120,23 +120,29 @@ dos_mbr_to_mbr(const struct dos_mbr *dmbr, const uint64_t lba_self,
 
        memcpy(dos_parts, dmbr->dmbr_parts, sizeof(dos_parts));
 
-       for (i = 0; i < NDOSPART; i++)
-               PRT_parse(&dos_parts[i], lba_self, lba_firstembr,
-                   &mbr->mbr_prt[i]);
+       for (i = 0; i < nitems(mbr->mbr_prt); i++) {
+               memset(&mbr->mbr_prt[i], 0, sizeof(mbr->mbr_prt[i]));
+               if (i < nitems(dmbr->dmbr_parts))
+                       PRT_parse(&dos_parts[i], lba_self, lba_firstembr,
+                           &mbr->mbr_prt[i]);
+       }
 }
 
 void
 mbr_to_dos_mbr(const struct mbr *mbr, struct dos_mbr *dos_mbr)
 {
        struct dos_partition    dos_partition;
-       int                     i;
+       unsigned int            i;
 
        memcpy(dos_mbr->dmbr_boot, mbr->mbr_code, sizeof(dos_mbr->dmbr_boot));
        dos_mbr->dmbr_sign = htole16(DOSMBR_SIGNATURE);
 
-       for (i = 0; i < NDOSPART; i++) {
-               PRT_make(&mbr->mbr_prt[i], mbr->mbr_lba_self,
-                   mbr->mbr_lba_firstembr, &dos_partition);
+       for (i = 0; i < nitems(dos_mbr->dmbr_parts); i++) {
+               memset(&dos_partition, 0, sizeof(dos_partition));
+               if (i < nitems(mbr->mbr_prt)) {
+                       PRT_make(&mbr->mbr_prt[i], mbr->mbr_lba_self,
+                           mbr->mbr_lba_firstembr, &dos_partition);
+               }
                memcpy(&dos_mbr->dmbr_parts[i], &dos_partition,
                    sizeof(dos_mbr->dmbr_parts[i]));
        }