Replace instances of the magic number '64' with a nice #define

BLOCKALIGNMENT. This will make it more obvious where this
512-byte block count could/should be converted to a disk sector
count.

No functional change.

4 files changed, 27 insertions, 24 deletions

diff --git a/sbin/fdisk/disk.h b/sbin/fdisk/disk.h
index 4f549e4bd3b..416aa6af8bb 100644
--- a/sbin/fdisk/disk.h
+++ b/sbin/fdisk/disk.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: disk.h,v 1.22 2021/05/07 22:15:13 krw Exp $	*/
+/*	$OpenBSD: disk.h,v 1.23 2021/06/25 19:24:53 krw Exp $	*/
 
 /*
  * Copyright (c) 1997 Tobias Weingartner
@@ -28,6 +28,9 @@ struct disk {
 	uint32_t size;
 };
 
+/* Align partition starts/sizes on 32K-byte boundaries. */
+#define	BLOCKALIGNMENT	64
+
 void  DISK_open(int);
 int  DISK_printgeometry(char *);
 char *DISK_readsector(off_t);
diff --git a/sbin/fdisk/fdisk.c b/sbin/fdisk/fdisk.c
index c76ae1f366a..b1f3870a964 100644
--- a/sbin/fdisk/fdisk.c
+++ b/sbin/fdisk/fdisk.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: fdisk.c,v 1.112 2021/06/23 13:07:13 krw Exp $	*/
+/*	$OpenBSD: fdisk.c,v 1.113 2021/06/25 19:24:53 krw Exp $	*/
 
 /*
  * Copyright (c) 1997 Tobias Weingartner
@@ -124,13 +124,13 @@ main(int argc, char *argv[])
 			parse_b(optarg, &b_sectors, &b_offset, &b_type);
 			break;
 		case 'l':
-			l_arg = strtonum(optarg, 64, UINT32_MAX, &errstr);
+			l_arg = strtonum(optarg, BLOCKALIGNMENT, UINT32_MAX, &errstr);
 			if (errstr)
-				errx(1, "Block argument %s [64..%u].", errstr,
-				    UINT32_MAX);
-			disk.cylinders = l_arg / 64;
+				errx(1, "Block argument %s [%u..%u].", errstr,
+				    BLOCKALIGNMENT, UINT32_MAX);
+			disk.cylinders = l_arg / BLOCKALIGNMENT;
 			disk.heads = 1;
-			disk.sectors = 64;
+			disk.sectors = BLOCKALIGNMENT;
 			disk.size = l_arg;
 			break;
 		case 'y':
@@ -169,9 +169,9 @@ main(int argc, char *argv[])
 		if (l_arg % bps != 0)
 			l_arg += bps - l_arg % bps;
 		l_arg = DL_BLKTOSEC(&dl, l_arg);
-		disk.cylinders = l_arg / 64;
+		disk.cylinders = l_arg / BLOCKALIGNMENT;
 		disk.heads = 1;
-		disk.sectors = 64;
+		disk.sectors = BLOCKALIGNMENT;
 		disk.size = l_arg;
 	}
 
diff --git a/sbin/fdisk/gpt.c b/sbin/fdisk/gpt.c
index a446ef437e6..83e5201f58d 100644
--- a/sbin/fdisk/gpt.c
+++ b/sbin/fdisk/gpt.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: gpt.c,v 1.32 2021/06/21 02:05:30 krw Exp $	*/
+/*	$OpenBSD: gpt.c,v 1.33 2021/06/25 19:24:53 krw Exp $	*/
 /*
  * Copyright (c) 2015 Markus Muller <mmu@grummel.net>
  * Copyright (c) 2015 Kenneth R Westerback <krw@openbsd.org>
@@ -334,8 +334,8 @@ add_partition(const uint8_t *beuuid, const char *name, uint64_t sectors)
 	if (rslt == -1)
 		goto done;
 
-	if (start % 64)
-		start += (64 - start % 64);
+	if (start % BLOCKALIGNMENT)
+		start += (BLOCKALIGNMENT - start % BLOCKALIGNMENT);
 	if (start >= end)
 		goto done;
 
@@ -386,9 +386,8 @@ init_gh(void)
 
 	needed = sizeof(gp) / secsize + 2;
 
-	/* Start usable LBA area on 64 sector boundary. */
-	if (needed % 64)
-		needed += (64 - (needed % 64));
+	if (needed % BLOCKALIGNMENT)
+		needed += (needed - (needed % BLOCKALIGNMENT));
 
 	gh.gh_sig = htole64(GPTSIGNATURE);
 	gh.gh_rev = htole32(GPTREVISION);
diff --git a/sbin/fdisk/misc.c b/sbin/fdisk/misc.c
index 8885d4659e5..56a80686e5c 100644
--- a/sbin/fdisk/misc.c
+++ b/sbin/fdisk/misc.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: misc.c,v 1.68 2021/06/20 18:44:19 krw Exp $	*/
+/*	$OpenBSD: misc.c,v 1.69 2021/06/25 19:24:53 krw Exp $	*/
 
 /*
  * Copyright (c) 1997 Tobias Weingartner
@@ -411,11 +411,11 @@ parse_b(const char *arg, uint32_t *blocks, uint32_t *offset, uint8_t *type)
 	uint32_t blockcount, blockoffset;
 	uint8_t partitiontype;
 
-	blockoffset = 64;
+	blockoffset = BLOCKALIGNMENT;
 	partitiontype = DOSPTYP_EFISYS;
 	ptype = NULL;
 
-	/* First number: # of sectors in boot partition. */
+	/* First number: # of 512-byte blocks in boot partition. */
 	poffset = strchr(arg, '@');
 	if (poffset != NULL)
 		*poffset++ = '\0';
@@ -425,18 +425,19 @@ parse_b(const char *arg, uint32_t *blocks, uint32_t *offset, uint8_t *type)
 			*ptype++ = '\0';
 	}
 
-	blockcount = strtonum(arg, 64, UINT32_MAX, &errstr);
+	blockcount = strtonum(arg, BLOCKALIGNMENT, UINT32_MAX, &errstr);
 	if (errstr)
-		errx(1, "Block argument %s [64..%u].",
-		    errstr, UINT32_MAX);
+		errx(1, "Block argument %s [%u..%u].", errstr, BLOCKALIGNMENT,
+		    UINT32_MAX);
 
 	if (poffset == NULL)
 		goto done;
 
-	blockoffset = strtonum(poffset, 64, UINT32_MAX, &errstr);
+	/* Second number: # of 512-byte blocks to offset partition start. */
+	blockoffset = strtonum(poffset, BLOCKALIGNMENT, UINT32_MAX, &errstr);
 	if (errstr)
-		errx(1, "Block offset argument %s "
-		    "[64..%u].", errstr, UINT32_MAX);
+		errx(1, "Block offset argument %s [%u..%u].", errstr,
+		    BLOCKALIGNMENT, UINT32_MAX);
 
 	if (ptype == NULL)
 		goto done;