Nuke some Capt. Obvious and soon to be obsolete comments in

GPT_write().

Add local variables prigh and prigp, mirroring altgh and altp, to
GPT_write(), eliminating some magic numbers to make clear the
relationship between the various primary and alternative GPT lba
fields.

No intentional functional change.

diff --git a/sbin/fdisk/gpt.c b/sbin/fdisk/gpt.c
index e145bb0..f68d2cd 100644 (file)
--- a/sbin/fdisk/gpt.c
+++ b/sbin/fdisk/gpt.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: gpt.c,v 1.15 2021/05/15 00:01:21 krw Exp $    */
+/*     $OpenBSD: gpt.c,v 1.16 2021/05/15 22:06:43 krw Exp $    */
 /*
  * Copyright (c) 2015 Markus Muller <mmu@grummel.net>
  * Copyright (c) 2015 Kenneth R Westerback <krw@openbsd.org>
@@ -388,33 +388,31 @@ GPT_write(void)
        const int secsize = unit_types[SECTORS].conversion;
        ssize_t len;
        off_t off;
-       uint64_t altgh, altgp;
+       uint64_t altgh, altgp, prigh, prigp;
 
        /* Assume we always write full-size partition table. XXX */
+       prigh = GPTSECTOR;
+       prigp = prigh + 1;
        altgh = DL_GETDSIZE(&dl) - 1;
        altgp = DL_GETDSIZE(&dl) - 1 - (sizeof(gp) / secsize);
 
-       /*
-        * Place the new GPT header at the start of sectors 1 and
-        * DL_GETDSIZE(lp)-1 and write the sectors back.
-        */
-       gh.gh_lba_self = htole64(1);
+       gh.gh_lba_self = htole64(prigh);
        gh.gh_lba_alt = htole64(altgh);
-       gh.gh_part_lba = htole64(2);
+       gh.gh_part_lba = htole64(prigp);
        gh.gh_part_csum = crc32((unsigned char *)&gp, sizeof(gp));
        gh.gh_csum = 0;
        gh.gh_csum = crc32((unsigned char *)&gh, letoh32(gh.gh_size));
 
-       secbuf = DISK_readsector(1);
+       secbuf = DISK_readsector(prigh);
        if (secbuf == NULL)
                return (-1);
 
        memcpy(secbuf, &gh, sizeof(gh));
-       DISK_writesector(secbuf, 1);
+       DISK_writesector(secbuf, prigh);
        free(secbuf);
 
        gh.gh_lba_self = htole64(altgh);
-       gh.gh_lba_alt = htole64(1);
+       gh.gh_lba_alt = htole64(prigh);
        gh.gh_part_lba = htole64(altgp);
        gh.gh_csum = 0;
        gh.gh_csum = crc32((unsigned char *)&gh, letoh32(gh.gh_size));
@@ -428,14 +426,11 @@ GPT_write(void)
        free(secbuf);
 
        /*
-        * Write partition table after primary header
-        * (i.e. at sector 1) and before alt header
-        * (i.e. ending in sector before alt header.
         * XXX ALWAYS NGPTPARTITIONS!
         * XXX ASSUME gp is multiple of sector size!
         */
-       off = lseek(disk.fd, secsize * 2, SEEK_SET);
-       if (off == secsize * 2)
+       off = lseek(disk.fd, secsize * prigp, SEEK_SET);
+       if (off == secsize * prigp)
                len = write(disk.fd, &gp, sizeof(gp));
        else
                len = -1;