Use a couple of local 'struct prt' variables to make MBR_init()

easier to read.

No functional change.

diff --git a/sbin/fdisk/mbr.c b/sbin/fdisk/mbr.c
index 3793e6a..f96b34d 100644 (file)
--- a/sbin/fdisk/mbr.c
+++ b/sbin/fdisk/mbr.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: mbr.c,v 1.102 2021/10/29 18:38:19 krw Exp $   */
+/*     $OpenBSD: mbr.c,v 1.103 2021/11/08 22:47:47 krw Exp $   */
 
 /*
  * Copyright (c) 1997 Tobias Weingartner
@@ -42,6 +42,7 @@ void
 MBR_init(struct mbr *mbr)
 {
        struct dos_partition    dp;
+       struct prt              bootprt, obsdprt;
        uint64_t                adj;
        daddr_t                 daddr;
 
@@ -57,70 +58,76 @@ MBR_init(struct mbr *mbr)
                return;
        }
 
-       memset(mbr, 0, sizeof(*mbr));
-       memcpy(mbr->mbr_code, default_dmbr.dmbr_boot, sizeof(mbr->mbr_code));
+       memset(&obsdprt, 0, sizeof(obsdprt));
+       memset(&bootprt, 0, sizeof(bootprt));
+
        memcpy(&dp, &default_dmbr.dmbr_parts[0], sizeof(dp));
-       PRT_parse(&dp, 0, 0, &mbr->mbr_prt[0]);
+       PRT_parse(&dp, 0, 0, &bootprt);
 
-       if (mbr->mbr_prt[0].prt_flag != DOSACTIVE)
-               mbr->mbr_prt[3].prt_flag = DOSACTIVE;
-       mbr->mbr_signature = DOSMBR_SIGNATURE;
+       if (bootprt.prt_flag != DOSACTIVE)
+               obsdprt.prt_flag = DOSACTIVE;
 
        /* Use whole disk. Reserve first track, or first cyl, if possible. */
-       mbr->mbr_prt[3].prt_id = DOSPTYP_OPENBSD;
+       obsdprt.prt_id = DOSPTYP_OPENBSD;
        if (disk.dk_heads > 1)
-               mbr->mbr_prt[3].prt_shead = 1;
+               obsdprt.prt_shead = 1;
        else
-               mbr->mbr_prt[3].prt_shead = 0;
+               obsdprt.prt_shead = 0;
        if (disk.dk_heads < 2 && disk.dk_cylinders > 1)
-               mbr->mbr_prt[3].prt_scyl = 1;
+               obsdprt.prt_scyl = 1;
        else
-               mbr->mbr_prt[3].prt_scyl = 0;
-       mbr->mbr_prt[3].prt_ssect = 1;
+               obsdprt.prt_scyl = 0;
+       obsdprt.prt_ssect = 1;
 
        /* Go right to the end */
-       mbr->mbr_prt[3].prt_ecyl = disk.dk_cylinders - 1;
-       mbr->mbr_prt[3].prt_ehead = disk.dk_heads - 1;
-       mbr->mbr_prt[3].prt_esect = disk.dk_sectors;
+       obsdprt.prt_ecyl = disk.dk_cylinders - 1;
+       obsdprt.prt_ehead = disk.dk_heads - 1;
+       obsdprt.prt_esect = disk.dk_sectors;
 
        /* Fix up start/length fields */
-       PRT_fix_BN(&mbr->mbr_prt[3], 3);
+       PRT_fix_BN(&obsdprt, 3);
 
 #if defined(__powerpc__) || defined(__mips__)
        /* Now fix up for the MS-DOS boot partition on PowerPC/MIPS. */
-       mbr->mbr_prt[0].prt_flag = DOSACTIVE;   /* Boot from dos part */
-       mbr->mbr_prt[3].prt_flag = 0;
-       mbr->mbr_prt[3].prt_ns += mbr->mbr_prt[3].prt_bs;
-       mbr->mbr_prt[3].prt_bs = mbr->mbr_prt[0].prt_bs + mbr->mbr_prt[0].prt_ns;
-       mbr->mbr_prt[3].prt_ns -= mbr->mbr_prt[3].prt_bs;
-       PRT_fix_CHS(&mbr->mbr_prt[3]);
-       if ((mbr->mbr_prt[3].prt_shead != 1) || (mbr->mbr_prt[3].prt_ssect != 1)) {
+       bootprt.prt_flag = DOSACTIVE;   /* Boot from dos part */
+       bootprt.prt_flag = 0;
+       obsdprt.prt_ns += obsdprt.prt_bs;
+       obsdprt.prt_bs = bootprt.prt_bs + bootptr.prt_ns;
+       obsdprt.prt_ns -= obsdprt.prt_bs;
+       PRT_fix_CHS(&obsdprt);
+       if ((obsdprt.prt_shead != 1) || (obsdprt.prt_ssect != 1)) {
                /* align the partition on a cylinder boundary */
-               mbr->mbr_prt[3].prt_shead = 0;
-               mbr->mbr_prt[3].prt_ssect = 1;
-               mbr->mbr_prt[3].prt_scyl += 1;
+               obsdprt.prt_shead = 0;
+               obsdprt.prt_ssect = 1;
+               obsdprt.prt_scyl += 1;
        }
        /* Fix up start/length fields */
-       PRT_fix_BN(&mbr->mbr_prt[3], 3);
+       PRT_fix_BN(&obsdprt, 3);
 #else
        if (disk.dk_bootprt.prt_ns > 0) {
-               mbr->mbr_prt[0] = disk.dk_bootprt;
-               PRT_fix_CHS(&mbr->mbr_prt[0]);
-               mbr->mbr_prt[3].prt_ns += mbr->mbr_prt[3].prt_bs;
-               mbr->mbr_prt[3].prt_bs = mbr->mbr_prt[0].prt_bs + mbr->mbr_prt[0].prt_ns;
-               mbr->mbr_prt[3].prt_ns -= mbr->mbr_prt[3].prt_bs;
-               PRT_fix_CHS(&mbr->mbr_prt[3]);
+               bootprt = disk.dk_bootprt;
+               PRT_fix_CHS(&bootprt);
+               obsdprt.prt_ns += obsdprt.prt_bs;
+               obsdprt.prt_bs = bootprt.prt_bs + bootprt.prt_ns;
+               obsdprt.prt_ns -= obsdprt.prt_bs;
+               PRT_fix_CHS(&obsdprt);
        }
 #endif
 
        /* Start OpenBSD MBR partition on a power of 2 block number. */
        daddr = 1;
-       while (daddr < DL_SECTOBLK(&dl, mbr->mbr_prt[3].prt_bs))
+       while (daddr < DL_SECTOBLK(&dl, obsdprt.prt_bs))
                daddr *= 2;
-       adj = DL_BLKTOSEC(&dl, daddr) - mbr->mbr_prt[3].prt_bs;
-       mbr->mbr_prt[3].prt_bs += adj;
-       mbr->mbr_prt[3].prt_ns -= adj;
-       PRT_fix_CHS(&mbr->mbr_prt[3]);
+       adj = DL_BLKTOSEC(&dl, daddr) - obsdprt.prt_bs;
+       obsdprt.prt_bs += adj;
+       obsdprt.prt_ns -= adj;
+       PRT_fix_CHS(&obsdprt);
+
+       memset(mbr, 0, sizeof(*mbr));
+       memcpy(mbr->mbr_code, default_dmbr.dmbr_boot, sizeof(mbr->mbr_code));
+       mbr->mbr_prt[0] = bootprt;
+       mbr->mbr_prt[3] = obsdprt;
+       mbr->mbr_signature = DOSMBR_SIGNATURE;
 }
 
 void