Consolidate disk geometry fiddling, turning -l/-c/-h/-s values into MBR

partition geometry info, into DISK_open(). Resulting in clearer logic.

No intentional functional change.

3 files changed, 61 insertions, 62 deletions

diff --git a/sbin/fdisk/disk.c b/sbin/fdisk/disk.c
index 880aa0be2ba..d742941505e 100644
--- a/sbin/fdisk/disk.c
+++ b/sbin/fdisk/disk.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: disk.c,v 1.63 2021/07/13 15:03:34 krw Exp $	*/
+/*	$OpenBSD: disk.c,v 1.64 2021/07/15 21:23:54 krw Exp $	*/
 
 /*
  * Copyright (c) 1997 Tobias Weingartner
@@ -16,7 +16,7 @@
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-#include <sys/types.h>
+#include <sys/param.h>		/* DEV_BSIZE */
 #include <sys/ioctl.h>
 #include <sys/dkio.h>
 #include <sys/stat.h>
@@ -28,6 +28,7 @@
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
 #include <util.h>
 
@@ -38,45 +39,53 @@ struct disk		disk;
 struct disklabel	dl;
 
 void
-DISK_open(const int rw)
+DISK_open(const char *name, const int oflags)
 {
 	struct stat		st;
 	uint64_t		sz, spc;
 
-	disk.dk_fd = opendev(disk.dk_name, rw ? O_RDWR : O_RDONLY, OPENDEV_PART,
-	    NULL);
+	disk.dk_name = strdup(name);
+	if (disk.dk_name == NULL)
+		err(1, "DISK_Open('%s')", name);
+
+	disk.dk_fd = opendev(disk.dk_name, oflags, OPENDEV_PART, NULL);
 	if (disk.dk_fd == -1)
 		err(1, "%s", disk.dk_name);
 	if (fstat(disk.dk_fd, &st) == -1)
 		err(1, "%s", disk.dk_name);
 	if (!S_ISCHR(st.st_mode))
 		errx(1, "%s is not a character device", disk.dk_name);
-
-	/* Get label geometry. */
-	if (ioctl(disk.dk_fd, DIOCGPDINFO, &dl) == -1) {
-		warn("DIOCGPDINFO");
+	if (ioctl(disk.dk_fd, DIOCGPDINFO, &dl) == -1)
+		err(1, "DIOCGPDINFO");
+
+	unit_types[SECTORS].ut_conversion = dl.d_secsize;
+
+	/* Set geometry to use in MBR partitions. */
+	if (disk.dk_size > 0) {
+		/* -l has set disk size. */
+		sz = DL_BLKTOSEC(&dl, disk.dk_size);
+		disk.dk_heads = 1;
+		disk.dk_sectors = 64;
+	} else if (disk.dk_cylinders > 0) {
+		/* -c/-h/-c has set disk geometry. */
+		sz = disk.dk_cylinders * disk.dk_heads * disk.dk_sectors;
+		sz = DL_BLKTOSEC(&dl, sz);
+		disk.dk_sectors = DL_BLKTOSEC(&dl, disk.dk_sectors);
 	} else {
-		unit_types[SECTORS].ut_conversion = dl.d_secsize;
-		if (disk.dk_size == 0) {
-			/* -l or -c/-h/-s not used. Use disklabel info. */
-			disk.dk_cylinders = dl.d_ncylinders;
-			disk.dk_heads = dl.d_ntracks;
-			disk.dk_sectors = dl.d_nsectors;
-			/* MBR handles only first UINT32_MAX sectors. */
-			spc = (uint64_t)disk.dk_heads * disk.dk_sectors;
-			sz = DL_GETDSIZE(&dl);
-			if (sz > UINT32_MAX) {
-				disk.dk_cylinders = UINT32_MAX / spc;
-				disk.dk_size = disk.dk_cylinders * spc;
-			} else
-				disk.dk_size = sz;
-		}
+		sz = DL_GETDSIZE(&dl);
+		disk.dk_heads = dl.d_ntracks;
+		disk.dk_sectors = dl.d_nsectors;
 	}
 
-	if (disk.dk_size == 0 || disk.dk_cylinders == 0 || disk.dk_heads == 0 ||
-	    disk.dk_sectors == 0 || unit_types[SECTORS].ut_conversion == 0)
-		errx(1, "Can't get disk geometry, please use [-chs] or [-l]"
-		    "to specify.");
+	if (sz > UINT32_MAX)
+		sz = UINT32_MAX;	/* MBR knows nothing > UINT32_MAX. */
+
+	spc = disk.dk_heads * disk.dk_sectors;
+	disk.dk_cylinders = sz / spc;
+	disk.dk_size = disk.dk_cylinders * spc;
+
+	if (disk.dk_size == 0)
+		errx(1, "dk_size == 0");
 }
 
 /*
diff --git a/sbin/fdisk/disk.h b/sbin/fdisk/disk.h
index 465449e2ed7..fe6bee275a4 100644
--- a/sbin/fdisk/disk.h
+++ b/sbin/fdisk/disk.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: disk.h,v 1.27 2021/07/13 15:03:34 krw Exp $	*/
+/*	$OpenBSD: disk.h,v 1.28 2021/07/15 21:23:54 krw Exp $	*/
 
 /*
  * Copyright (c) 1997 Tobias Weingartner
@@ -31,7 +31,7 @@ struct disk {
 /* Align partition starts/sizes on 32K-byte boundaries. */
 #define	BLOCKALIGNMENT	64
 
-void		 DISK_open(const int);
+void		 DISK_open(const char *, const int);
 int		 DISK_printgeometry(const char *);
 char		*DISK_readsector(const uint64_t);
 int		 DISK_writesector(const char *, const uint64_t);
diff --git a/sbin/fdisk/fdisk.c b/sbin/fdisk/fdisk.c
index 21670d08aaa..d90fb9daf10 100644
--- a/sbin/fdisk/fdisk.c
+++ b/sbin/fdisk/fdisk.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: fdisk.c,v 1.119 2021/07/12 14:06:19 krw Exp $	*/
+/*	$OpenBSD: fdisk.c,v 1.120 2021/07/15 21:23:54 krw Exp $	*/
 
 /*
  * Copyright (c) 1997 Tobias Weingartner
@@ -75,8 +75,7 @@ main(int argc, char *argv[])
 	unsigned int		 bps;
 	int			 e_flag = 0, g_flag = 0, i_flag = 0, u_flag = 0;
 	int			 verbosity = TERSE;
-	int			 c_arg = 0, h_arg = 0, s_arg = 0;
-	uint32_t		 l_arg = 0;
+	int			 oflags = O_RDONLY;
 	char			*query;
 
 	while ((ch = getopt(argc, argv, "Aiegpuvf:c:h:s:l:b:y")) != -1) {
@@ -85,40 +84,41 @@ main(int argc, char *argv[])
 		switch(ch) {
 		case 'A':
 			A_flag = 1;
+			oflags = O_RDWR;
 			break;
 		case 'i':
 			i_flag = 1;
+			oflags = O_RDWR;
 			break;
 		case 'u':
 			u_flag = 1;
+			oflags = O_RDWR;
 			break;
 		case 'e':
 			e_flag = 1;
+			oflags = O_RDWR;
 			break;
 		case 'f':
 			mbrfile = optarg;
 			break;
 		case 'c':
-			c_arg = strtonum(optarg, 1, 262144, &errstr);
+			disk.dk_cylinders = strtonum(optarg, 1, 262144, &errstr);
 			if (errstr)
 				errx(1, "Cylinder argument %s [1..262144].",
 				    errstr);
-			disk.dk_cylinders = c_arg;
-			disk.dk_size = c_arg * h_arg * s_arg;
+			disk.dk_size = 0;
 			break;
 		case 'h':
-			h_arg = strtonum(optarg, 1, 256, &errstr);
+			disk.dk_heads = strtonum(optarg, 1, 256, &errstr);
 			if (errstr)
 				errx(1, "Head argument %s [1..256].", errstr);
-			disk.dk_heads = h_arg;
-			disk.dk_size = c_arg * h_arg * s_arg;
+			disk.dk_size = 0;
 			break;
 		case 's':
-			s_arg = strtonum(optarg, 1, 63, &errstr);
+			disk.dk_sectors = strtonum(optarg, 1, 63, &errstr);
 			if (errstr)
 				errx(1, "Sector argument %s [1..63].", errstr);
-			disk.dk_sectors = s_arg;
-			disk.dk_size = c_arg * h_arg * s_arg;
+			disk.dk_size = 0;
 			break;
 		case 'g':
 			g_flag = 1;
@@ -127,14 +127,11 @@ main(int argc, char *argv[])
 			parse_b(optarg, &b_sectors, &b_offset, &b_type);
 			break;
 		case 'l':
-			l_arg = strtonum(optarg, BLOCKALIGNMENT, UINT32_MAX, &errstr);
+			disk.dk_size = strtonum(optarg, BLOCKALIGNMENT, UINT32_MAX, &errstr);
 			if (errstr)
 				errx(1, "Block argument %s [%u..%u].", errstr,
 				    BLOCKALIGNMENT, UINT32_MAX);
-			disk.dk_cylinders = l_arg / BLOCKALIGNMENT;
-			disk.dk_heads = 1;
-			disk.dk_sectors = BLOCKALIGNMENT;
-			disk.dk_size = l_arg;
+			disk.dk_cylinders = disk.dk_heads = disk.dk_sectors = 0;
 			break;
 		case 'y':
 			y_flag = 1;
@@ -152,13 +149,15 @@ main(int argc, char *argv[])
 	/* Argument checking */
 	if (argc != 1 || (i_flag && u_flag) ||
 	    (i_flag == 0 && g_flag) ||
-	    (b_sectors && !(i_flag || A_flag)) ||
-	    ((c_arg | h_arg | s_arg) && !(c_arg && h_arg && s_arg)) ||
-	    ((c_arg | h_arg | s_arg) && l_arg))
+	    (b_sectors && !(i_flag || A_flag)))
 		usage();
 
-	disk.dk_name = argv[0];
-	DISK_open(A_flag || i_flag || u_flag || e_flag);
+	if ((disk.dk_cylinders || disk.dk_heads || disk.dk_sectors) &&
+	    (disk.dk_cylinders * disk.dk_heads * disk.dk_sectors == 0))
+		usage();
+
+	DISK_open(argv[0], oflags);
+
 	bps = DL_BLKSPERSEC(&dl);
 	if (b_sectors > 0) {
 		if (b_sectors % bps != 0)
@@ -168,15 +167,6 @@ main(int argc, char *argv[])
 		b_sectors = DL_BLKTOSEC(&dl, b_sectors);
 		b_offset = DL_BLKTOSEC(&dl, b_offset);
 	}
-	if (l_arg > 0) {
-		if (l_arg % bps != 0)
-			l_arg += bps - l_arg % bps;
-		l_arg = DL_BLKTOSEC(&dl, l_arg);
-		disk.dk_cylinders = l_arg / BLOCKALIGNMENT;
-		disk.dk_heads = 1;
-		disk.dk_sectors = BLOCKALIGNMENT;
-		disk.dk_size = l_arg;
-	}
 
 	/* "proc exec" for man page display */
 	if (pledge("stdio rpath wpath disklabel proc exec", NULL) == -1)
@@ -192,7 +182,7 @@ main(int argc, char *argv[])
 	if (efi != -1)
 		GPT_read(ANYGPT);
 
-	if (!(A_flag || i_flag || u_flag || e_flag)) {
+	if (oflags == O_RDONLY) {
 		if (pledge("stdio", NULL) == -1)
 			err(1, "pledge");
 		USER_print_disk(verbosity);