diff --git a/fdisk/fdisk.c b/fdisk/fdisk.c
index 4bab260cf..dedb5f8b2 100644
--- a/fdisk/fdisk.c
+++ b/fdisk/fdisk.c
@@ -1,6 +1,7 @@
 /* fdisk.c -- Partition table manipulator for Linux.
  *
  * Copyright (C) 1992  A. V. Le Blanc (LeBlanc@mcc.ac.uk)
+ * Copyright (C) 2012  Davidlohr Bueso <dave@gnu.org>
  *
  * This program is free software.  You can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
@@ -50,7 +51,6 @@
 
 #include "gpt.h"
 
-unsigned char *MBRbuffer;
 int MBRbuffer_changed;
 
 #define hex_val(c)	({ \
@@ -231,10 +231,10 @@ void print_menu(enum menutype menu)
 }
 
 static int
-get_sysid(int i) {
+get_sysid(struct fdisk_context *cxt, int i) {
 	return (
-		disklabel == SUN_LABEL ? sun_get_sysid(i) :
-		disklabel == SGI_LABEL ? sgi_get_sysid(i) :
+		disklabel == SUN_LABEL ? sun_get_sysid(cxt, i) :
+		disklabel == SGI_LABEL ? sgi_get_sysid(cxt, i) :
 		ptes[i].part_table->sys_ind);
 }
 
@@ -439,8 +439,8 @@ void warn_alignment(struct fdisk_context *cxt)
 }
 
 static void
-get_partition_table_geometry(void) {
-	unsigned char *bufp = MBRbuffer;
+get_partition_table_geometry(struct fdisk_context *cxt) {
+	unsigned char *bufp = cxt->mbr;
 	struct partition *p;
 	int i, h, s, hh, ss;
 	int first = 1;
@@ -530,7 +530,7 @@ get_geometry(struct fdisk_context *cxt, struct geom *g)
 	pt_heads = pt_sectors = 0;
 
 	blkdev_get_geometry(cxt->dev_fd, &kern_heads, &kern_sectors);
-	get_partition_table_geometry();
+	get_partition_table_geometry(cxt);
 
 	heads = user_heads ? user_heads :
 		pt_heads ? pt_heads :
@@ -555,27 +555,6 @@ get_geometry(struct fdisk_context *cxt, struct geom *g)
 	}
 }
 
-/*
- * Please, always use allocated buffer if you want to cast the buffer to
- * any struct -- cast non-allocated buffer to any struct is against
- * strict-aliasing rules.  --kzak 16-Oct-2009
- */
-static void init_mbr_buffer(void)
-{
-	if (MBRbuffer)
-		return;
-
-	MBRbuffer = xcalloc(1, MAX_SECTOR_SIZE);
-}
-
-void zeroize_mbr_buffer(void)
-{
-	if (MBRbuffer)
-		memset(MBRbuffer, 0, MAX_SECTOR_SIZE);
-}
-
-
-
 /*
  * Read MBR.  Returns:
  *   -1: no 0xaa55 flag present (possibly entire disk BSD)
@@ -585,25 +564,19 @@ void zeroize_mbr_buffer(void)
 static int get_boot(struct fdisk_context *cxt, int try_only) {
 
 	disklabel = ANY_LABEL;
-	memset(MBRbuffer, 0, 512);
-
-	if (512 != read(cxt->dev_fd, MBRbuffer, 512)) {
-		if (try_only)
-			return 1;
-		fatal(cxt, unable_to_read);
-	}
 
 	get_geometry(cxt, NULL);
 	update_units();
 
 	if (!check_dos_label(cxt))
-		if (check_sun_label() || check_sgi_label() || check_aix_label() || check_mac_label())
+		if (check_sun_label(cxt) || check_sgi_label(cxt) || check_aix_label(cxt)
+		    || check_mac_label(cxt))
 			return 0;
 
 	if (check_osf_label(cxt)) {
 		/* intialize partitions for BSD as well */
 		dos_init(cxt);
-		if (!valid_part_table_flag(MBRbuffer)) {
+		if (!valid_part_table_flag(cxt->mbr)) {
 			disklabel = OSF_LABEL;
 			return 0;
 		}
@@ -879,7 +852,7 @@ get_partition_dflt(struct fdisk_context *cxt, int warn, int max, int dflt) {
 		    || (disklabel == SUN_LABEL &&
 			(!sunlabel->partitions[i].num_sectors ||
 			 !sunlabel->part_tags[i].tag))
-		    || (disklabel == SGI_LABEL && (!sgi_get_num_sectors(i)))
+		    || (disklabel == SGI_LABEL && (!sgi_get_num_sectors(cxt, i)))
 		   )
 			fprintf(stderr,
 				_("Warning: partition %d has empty type\n"),
@@ -983,7 +956,7 @@ delete_partition(struct fdisk_context *cxt, int i)
 	if (disklabel == DOS_LABEL)
 		dos_delete_partition(i);
 	else if (disklabel == SUN_LABEL)
-		sun_delete_partition(i);
+		sun_delete_partition(cxt, i);
 	else if (disklabel == SGI_LABEL)
 		sgi_delete_partition(cxt, i);
 
@@ -1001,7 +974,7 @@ static void change_sysid(struct fdisk_context *cxt)
 	if (i == -1)
 		return;
 	p = ptes[i].part_table;
-	origsys = sys = get_sysid(i);
+	origsys = sys = get_sysid(cxt, i);
 
 	/* if changing types T to 0 is allowed, then
 	   the reverse change must be allowed, too */
@@ -1042,10 +1015,10 @@ static void change_sysid(struct fdisk_context *cxt)
                         if (sys == origsys)
 				break;
 			if (disklabel == SUN_LABEL) {
-				ptes[i].changed = sun_change_sysid(i, sys);
+				ptes[i].changed = sun_change_sysid(cxt, i, sys);
 			} else
 			if (disklabel == SGI_LABEL) {
-				ptes[i].changed = sgi_change_sysid(i, sys);
+				ptes[i].changed = sgi_change_sysid(cxt, i, sys);
 			} else {
 				p->sys_ind = sys;
 				ptes[i].changed = 1;
@@ -1168,7 +1141,7 @@ list_disk_geometry(struct fdisk_context *cxt) {
 	if (cxt->alignment_offset)
 		printf(_("Alignment offset: %lu bytes\n"), cxt->alignment_offset);
 	if (disklabel == DOS_LABEL)
-		dos_print_mbr_id();
+		dos_print_mbr_id(cxt);
 	printf("\n");
 }
 
@@ -1471,12 +1444,12 @@ verify(struct fdisk_context *cxt) {
 		return;
 
 	if (disklabel == SUN_LABEL) {
-		verify_sun();
+		verify_sun(cxt);
 		return;
 	}
 
 	if (disklabel == SGI_LABEL) {
-		verify_sgi(1);
+		verify_sgi(cxt, 1);
 		return;
 	}
 
@@ -1671,7 +1644,7 @@ static void print_raw(struct fdisk_context *cxt)
 
 	printf(_("Device: %s\n"), cxt->dev_path);
 	if (disklabel == SUN_LABEL || disklabel == SGI_LABEL)
-		print_buffer(cxt, MBRbuffer);
+		print_buffer(cxt, cxt->mbr);
 	else for (i = 3; i < partitions; i++)
 		     print_buffer(cxt, ptes[i].sectorbuffer);
 }
@@ -1754,7 +1727,7 @@ expert_command_prompt(struct fdisk_context *cxt)
 				read_int(cxt, 1, cylinders, 1048576, 0,
 					 _("Number of cylinders"));
 			if (disklabel == SUN_LABEL)
-				sun_set_ncyl(cylinders);
+				sun_set_ncyl(cxt, cylinders);
 			break;
 		case 'd':
 			print_raw(cxt);
@@ -1784,7 +1757,7 @@ expert_command_prompt(struct fdisk_context *cxt)
 			if (disklabel == SUN_LABEL)
 				sun_set_ilfact(cxt);
 			else if (disklabel == DOS_LABEL)
-				dos_set_mbr_id();
+				dos_set_mbr_id(cxt);
 			break;
 		case 'o':
 			if (disklabel == SUN_LABEL)
@@ -1942,17 +1915,17 @@ static void command_prompt(struct fdisk_context *cxt)
 			if (disklabel == DOS_LABEL)
 				toggle_active(get_partition(cxt, 1, partitions));
 			else if (disklabel == SUN_LABEL)
-				toggle_sunflags(get_partition(cxt, 1, partitions),
+				toggle_sunflags(cxt, get_partition(cxt, 1, partitions),
 						SUN_FLAG_UNMNT);
 			else if (disklabel == SGI_LABEL)
-				sgi_set_bootpartition(
+				sgi_set_bootpartition(cxt,
 					get_partition(cxt, 1, partitions));
 			else
 				unknown_command(c);
 			break;
 		case 'b':
 			if (disklabel == SGI_LABEL)
-				sgi_set_bootfile();
+				sgi_set_bootfile(cxt);
 			else if (disklabel == DOS_LABEL) {
 				disklabel = OSF_LABEL;
 				bsd_command_prompt(cxt);
@@ -1964,10 +1937,10 @@ static void command_prompt(struct fdisk_context *cxt)
 			if (disklabel == DOS_LABEL)
 				toggle_dos_compatibility_flag(cxt);
 			else if (disklabel == SUN_LABEL)
-				toggle_sunflags(get_partition(cxt, 1, partitions),
+				toggle_sunflags(cxt, get_partition(cxt, 1, partitions),
 						SUN_FLAG_RONLY);
 			else if (disklabel == SGI_LABEL)
-				sgi_set_swappartition(
+				sgi_set_swappartition(cxt,
 					get_partition(cxt, 1, partitions));
 			else
 				unknown_command(c);
@@ -1977,7 +1950,7 @@ static void command_prompt(struct fdisk_context *cxt)
 			break;
 		case 'i':
 			if (disklabel == SGI_LABEL)
-				create_sgiinfo();
+				create_sgiinfo(cxt);
 			else
 				unknown_command(c);
 			break;
@@ -2113,7 +2086,7 @@ int main(int argc, char **argv)
 		printf(_("Warning: the -b (set sector size) option should"
 			 " be used with one specified device\n"));
 
-	init_mbr_buffer();
+	/* init_mbr_buffer(); */
 
 	if (optl) {
 		nowarn = 1;
diff --git a/fdisk/fdisk.h b/fdisk/fdisk.h
index 9d17cdd76..b4f2814f9 100644
--- a/fdisk/fdisk.h
+++ b/fdisk/fdisk.h
@@ -104,8 +104,9 @@ struct geom {
 typedef unsigned long long sector_t;
 
 struct fdisk_context {
-	int dev_fd;     /* device descriptor */
-	char *dev_path; /* device path */
+	int dev_fd;         /* device descriptor */
+	char *dev_path;     /* device path */
+	unsigned char *mbr; /* buffer with master boot record */
 
 	/* topology */
 	unsigned long io_size;		/* I/O size used by fdisk */
@@ -123,6 +124,7 @@ extern struct fdisk_context *fdisk_new_context_from_filename(const char *fname,
 extern int fdisk_dev_has_topology(struct fdisk_context *cxt);
 extern int fdisk_dev_sectsz_is_default(struct fdisk_context *cxt);
 extern void fdisk_free_context(struct fdisk_context *cxt);
+extern void fdisk_mbr_zeroize(struct fdisk_context *cxt);
 
 /* prototypes for fdisk.c */
 extern char *disk_device, *line_ptr;
@@ -145,7 +147,6 @@ extern unsigned int read_int(struct fdisk_context *cxt,
 extern void print_menu(enum menutype);
 extern void print_partition_size(struct fdisk_context *cxt, int num, sector_t start, sector_t stop, int sysid);
 
-extern void zeroize_mbr_buffer(void);
 extern void fill_bounds(sector_t *first, sector_t *last);
 extern unsigned int heads, cylinders;
 extern sector_t sectors;
@@ -180,12 +181,6 @@ enum labeltype {
 };
 
 extern enum labeltype disklabel;
-
-/*
- * Raw disk label. For DOS-type partition tables the MBR,
- * with descriptions of the primary partitions.
- */
-extern unsigned char *MBRbuffer;
 extern int MBRbuffer_changed;
 extern unsigned long grain;
 
diff --git a/fdisk/fdiskaixlabel.c b/fdisk/fdiskaixlabel.c
index 9fde61f7a..c15ab749b 100644
--- a/fdisk/fdiskaixlabel.c
+++ b/fdisk/fdiskaixlabel.c
@@ -14,6 +14,8 @@
 #include "fdiskaixlabel.h"
 #include "nls.h"
 
+#define aixlabel ((aix_partition *)cxt->mbr)
+
 static	int     other_endian = 0;
 static  short	volumes=1;
 
@@ -39,16 +41,15 @@ aix_info( void ) {
 }
 
 void
-aix_nolabel( void )
+aix_nolabel(struct fdisk_context *cxt)
 {
     aixlabel->magic = 0;
     partitions = 4;
-    zeroize_mbr_buffer();
+    fdisk_mbr_zeroize(cxt);
     return;
 }
 
-int
-check_aix_label( void )
+int check_aix_label(struct fdisk_context *cxt)
 {
     if (aixlabel->magic != AIX_LABEL_MAGIC &&
 	aixlabel->magic != AIX_LABEL_MAGIC_SWAPPED) {
@@ -61,6 +62,6 @@ check_aix_label( void )
     partitions= 1016;
     volumes = 15;
     aix_info();
-    aix_nolabel();		/* %% */
+    aix_nolabel(cxt);		/* %% */
     return 1;
 }
diff --git a/fdisk/fdiskaixlabel.h b/fdisk/fdiskaixlabel.h
index 324b9ae24..bd4cb2781 100644
--- a/fdisk/fdiskaixlabel.h
+++ b/fdisk/fdiskaixlabel.h
@@ -20,12 +20,8 @@ typedef struct {
 #define	AIX_INFO_MAGIC		0x00072959
 #define	AIX_INFO_MAGIC_SWAPPED	0x59290700
 
-/* fdisk.c */
-#define aixlabel ((aix_partition *)MBRbuffer)
-
 /* fdiskaixlabel.c */
 extern struct	systypes aix_sys_types[];
-extern void	aix_nolabel( void );
-extern int	check_aix_label( void );
+extern int	check_aix_label(struct fdisk_context *cxt);
 
 #endif /* FDISK_AIX_LABEL_H */
diff --git a/fdisk/fdiskdoslabel.c b/fdisk/fdiskdoslabel.c
index 299cff83c..abf101b32 100644
--- a/fdisk/fdiskdoslabel.c
+++ b/fdisk/fdiskdoslabel.c
@@ -108,10 +108,10 @@ void dos_init(struct fdisk_context *cxt)
 	for (i = 0; i < 4; i++) {
 		struct pte *pe = &ptes[i];
 
-		pe->part_table = pt_offset(MBRbuffer, i);
+		pe->part_table = pt_offset(cxt->mbr, i);
 		pe->ext_pointer = NULL;
 		pe->offset = 0;
-		pe->sectorbuffer = MBRbuffer;
+		pe->sectorbuffer = cxt->mbr;
 		pe->changed = 0;
 	}
 
@@ -214,9 +214,9 @@ static void read_extended(struct fdisk_context *cxt, int ext)
 	}
 }
 
-void dos_print_mbr_id(void)
+void dos_print_mbr_id(struct fdisk_context *cxt)
 {
-	printf(_("Disk identifier: 0x%08x\n"), dos_read_mbr_id(MBRbuffer));
+	printf(_("Disk identifier: 0x%08x\n"), dos_read_mbr_id(cxt->mbr));
 }
 
 void create_doslabel(struct fdisk_context *cxt)
@@ -229,26 +229,25 @@ void create_doslabel(struct fdisk_context *cxt)
 	fprintf(stderr, _("Building a new DOS disklabel with disk identifier 0x%08x.\n"), id);
 
 	dos_init(cxt);
-	zeroize_mbr_buffer();
-
+	fdisk_mbr_zeroize(cxt);
 	set_all_unchanged();
 	set_changed(0);
 
 	/* Generate an MBR ID for this disk */
-	dos_write_mbr_id(MBRbuffer, id);
+	dos_write_mbr_id(cxt->mbr, id);
 
 	/* Put MBR signature */
-	write_part_table_flag(MBRbuffer);
+	write_part_table_flag(cxt->mbr);
 }
 
-void dos_set_mbr_id(void)
+void dos_set_mbr_id(struct fdisk_context *cxt)
 {
 	unsigned long new_id;
 	char *ep;
 	char ps[64];
 
 	snprintf(ps, sizeof ps, _("New disk identifier (current 0x%08x): "),
-		 dos_read_mbr_id(MBRbuffer));
+		 dos_read_mbr_id(cxt->mbr));
 
 	if (read_chars(ps) == '\n')
 		return;
@@ -257,9 +256,9 @@ void dos_set_mbr_id(void)
 	if (*ep != '\n')
 		return;
 
-	dos_write_mbr_id(MBRbuffer, new_id);
+	dos_write_mbr_id(cxt->mbr, new_id);
 	MBRbuffer_changed = 1;
-	dos_print_mbr_id();
+	dos_print_mbr_id(cxt);
 }
 
 void dos_delete_partition(int i)
@@ -321,7 +320,7 @@ int check_dos_label(struct fdisk_context *cxt)
 {
 	int i;
 
-	if (!valid_part_table_flag(MBRbuffer))
+	if (!valid_part_table_flag(cxt->mbr))
 		return 0;
 
 	dos_init(cxt);
@@ -668,8 +667,8 @@ void dos_write_table(struct fdisk_context *cxt)
 				MBRbuffer_changed = 1;
 	}
 	if (MBRbuffer_changed) {
-		write_part_table_flag(MBRbuffer);
-		write_sector(cxt, 0, MBRbuffer);
+		write_part_table_flag(cxt->mbr);
+		write_sector(cxt, 0, cxt->mbr);
 	}
 	/* EBR (logical partitions) */
 	for (i = 4; i < partitions; i++) {
diff --git a/fdisk/fdiskdoslabel.h b/fdisk/fdiskdoslabel.h
index 8d62d52e8..f64a4cedd 100644
--- a/fdisk/fdiskdoslabel.h
+++ b/fdisk/fdiskdoslabel.h
@@ -44,8 +44,8 @@ static inline sector_t get_partition_start(struct pte *pe)
 }
 
 extern void create_doslabel(struct fdisk_context *cxt);
-extern void dos_print_mbr_id(void);
-extern void dos_set_mbr_id(void);
+extern void dos_print_mbr_id(struct fdisk_context *cxt);
+extern void dos_set_mbr_id(struct fdisk_context *cxt);
 extern void dos_delete_partition(int i);
 extern int check_dos_label(struct fdisk_context *cxt);
 extern int is_dos_partition(int t);
diff --git a/fdisk/fdiskmaclabel.c b/fdisk/fdiskmaclabel.c
index e82347d73..1c2e403e7 100644
--- a/fdisk/fdiskmaclabel.c
+++ b/fdisk/fdiskmaclabel.c
@@ -39,16 +39,16 @@ mac_info( void ) {
 }
 
 void
-mac_nolabel( void )
+mac_nolabel(struct fdisk_context *cxt)
 {
     maclabel->magic = 0;
     partitions = 4;
-    zeroize_mbr_buffer();
+    fdisk_mbr_zeroize(cxt);
     return;
 }
 
 int
-check_mac_label( void )
+check_mac_label(struct fdisk_context *cxt)
 {
 	/*
 	Conversion: only 16 bit should compared
@@ -77,7 +77,7 @@ IS_MAC:
     partitions= 1016; // =?
     volumes = 15;	// =?
     mac_info();
-    mac_nolabel();		/* %% */
+    mac_nolabel(cxt);		/* %% */
     return 1;
 }
 
diff --git a/fdisk/fdiskmaclabel.h b/fdisk/fdiskmaclabel.h
index e664a155a..4873dcdf0 100644
--- a/fdisk/fdiskmaclabel.h
+++ b/fdisk/fdiskmaclabel.h
@@ -28,12 +28,12 @@ typedef struct {
 #define	MAC_LABEL_MAGIC_3_SWAPPED	0x0000d405
 
 /* fdisk.c */
-#define maclabel ((mac_partition *)MBRbuffer)
+#define maclabel ((mac_partition *)cxt->mbr)
 
 /* fdiskmaclabel.c */
 extern struct	systypes mac_sys_types[];
-extern void	mac_nolabel( void );
-extern int	check_mac_label( void );
+extern void	mac_nolabel(struct fdisk_context *cxt);
+extern int	check_mac_label(struct fdisk_context *cxt);
 
 #endif /* FDISK_MAC_LABEL_H */
 
diff --git a/fdisk/fdisksgilabel.c b/fdisk/fdisksgilabel.c
index 9c425b393..1a10296d0 100644
--- a/fdisk/fdisksgilabel.c
+++ b/fdisk/fdisksgilabel.c
@@ -11,7 +11,11 @@
  *
  * 2003-03-20 Phillip Kesling <pkesling@sgi.com>
  *      Some fixes
+ *
+ * 2012-06-16 Davidlohr Bueso <dave@gnu.org>
+ *      Adapt to fdisk context and add heap sort for partitions
  */
+
 #include <stdio.h>              /* stderr */
 #include <stdlib.h>		/* exit */
 #include <string.h>             /* strstr */
@@ -103,12 +107,12 @@ struct systypes sgi_sys_types[] = {
 };
 
 static int
-sgi_get_nsect(void) {
+sgi_get_nsect(struct fdisk_context *cxt) {
 	return SSWAP16(sgilabel->devparam.nsect);
 }
 
 static int
-sgi_get_ntrks(void) {
+sgi_get_ntrks(struct fdisk_context *cxt) {
 	return SSWAP16(sgilabel->devparam.ntrks);
 }
 
@@ -130,7 +134,7 @@ sgi_get_pcylcount(void) {
 #endif
 
 void
-sgi_nolabel() {
+sgi_nolabel(struct fdisk_context *cxt) {
 	sgilabel->magic = 0;
 	partitions = 4;
 }
@@ -147,7 +151,7 @@ two_s_complement_32bit_sum(unsigned int *base, int size /* in bytes */) {
 }
 
 int
-check_sgi_label() {
+check_sgi_label(struct fdisk_context *cxt) {
 	if (sizeof(sgilabel) > 512) {
 		fprintf(stderr,
 			_("According to MIPS Computer Systems, Inc the "
@@ -209,21 +213,21 @@ sgi_list_table(struct fdisk_context *cxt, int xtra) {
 		 "Pt# %*s  Info     Start       End   Sectors  Id  System\n"),
 	       w + 1, _("Device"));
 	for (i = 0 ; i < partitions; i++) {
-		if (sgi_get_num_sectors(i) || debug) {
-			uint32_t start = sgi_get_start_sector(i);
-			uint32_t len = sgi_get_num_sectors(i);
+		if (sgi_get_num_sectors(cxt, i) || debug) {
+			uint32_t start = sgi_get_start_sector(cxt, i);
+			uint32_t len = sgi_get_num_sectors(cxt, i);
 			kpi++;		/* only count nonempty partitions */
 			printf(
 				"%2d: %s %4s %9ld %9ld %9ld  %2x  %s\n",
 /* fdisk part number */   i+1,
 /* device */              partname(cxt->dev_path, kpi, w+2),
-/* flags */               (sgi_get_swappartition() == i) ? "swap" :
-/* flags */               (sgi_get_bootpartition() == i) ? "boot" : "    ", 
+/* flags */               (sgi_get_swappartition(cxt) == i) ? "swap" :
+/* flags */               (sgi_get_bootpartition(cxt) == i) ? "boot" : "    ",
 /* start */               (long) scround(start),
 /* end */                 (long) scround(start+len)-1,
 /* no odd flag on end */  (long) len, 
-/* type id */             sgi_get_sysid(i),
-/* type name */           (type = partition_type(sgi_get_sysid(i)))
+/* type id */             sgi_get_sysid(cxt, i),
+/* type name */           (type = partition_type(sgi_get_sysid(cxt, i)))
 				? type : _("Unknown"));
 		}
 	}
@@ -243,35 +247,35 @@ sgi_list_table(struct fdisk_context *cxt, int xtra) {
 }
 
 unsigned int
-sgi_get_start_sector(int i) {
+sgi_get_start_sector(struct fdisk_context *cxt, int i) {
 	return SSWAP32(sgilabel->partitions[i].start_sector);
 }
 
 unsigned int
-sgi_get_num_sectors(int i) {
+sgi_get_num_sectors(struct fdisk_context *cxt, int i) {
 	return SSWAP32(sgilabel->partitions[i].num_sectors);
 }
 
 int
-sgi_get_sysid(int i)
+sgi_get_sysid(struct fdisk_context *cxt, int i)
 {
 	return SSWAP32(sgilabel->partitions[i].id);
 }
 
 int
-sgi_get_bootpartition(void)
+sgi_get_bootpartition(struct fdisk_context *cxt)
 {
 	return (short) SSWAP16(sgilabel->boot_part);
 }
 
 int
-sgi_get_swappartition(void)
+sgi_get_swappartition(struct fdisk_context *cxt)
 {
 	return (short) SSWAP16(sgilabel->swap_part);
 }
 
 void
-sgi_set_bootpartition(int i)
+sgi_set_bootpartition(struct fdisk_context *cxt, int i)
 {
 	sgilabel->boot_part = SSWAP16(((short)i));
 }
@@ -282,12 +286,12 @@ sgi_get_lastblock(void) {
 }
 
 void
-sgi_set_swappartition(int i) {
+sgi_set_swappartition(struct fdisk_context *cxt, int i) {
 	sgilabel->swap_part = SSWAP16(((short)i));
 }
 
 static int
-sgi_check_bootfile(const char* aFile) {
+sgi_check_bootfile(struct fdisk_context *cxt, const char* aFile) {
 	if (strlen(aFile) < 3) /* "/a\n" is minimum */ {
 		printf(_("\nInvalid Bootfile!\n"
 			 "\tThe bootfile must be an absolute non-zero pathname,\n"
@@ -316,7 +320,7 @@ sgi_check_bootfile(const char* aFile) {
 }
 
 void
-sgi_set_bootfile(void)
+sgi_set_bootfile(struct fdisk_context *cxt)
 {
 	printf(_("\nThe current boot file is: %s\n"), sgilabel->boot_file);
 	if (read_chars(_("Please enter the name of the new boot file: ")) == '\n') {
@@ -324,7 +328,7 @@ sgi_set_bootfile(void)
 		return;
 	}
 
-	if (sgi_check_bootfile(line_ptr)) {
+	if (sgi_check_bootfile(cxt, line_ptr)) {
 		size_t i = 0;
 		while (i < 16) {
 			if ((line_ptr[i] != '\n')	/* in principle caught again by next line */
@@ -340,7 +344,7 @@ sgi_set_bootfile(void)
 }
 
 void
-create_sgiinfo(void) {
+create_sgiinfo(struct fdisk_context *cxt) {
 	/* I keep SGI's habit to write the sgilabel to the second block */
 	sgilabel->directory[0].vol_file_start = SSWAP32(2);
 	sgilabel->directory[0].vol_file_size = SSWAP32(sizeof(sgiinfo));
@@ -378,18 +382,18 @@ sgi_write_table(struct fdisk_context *cxt) {
 }
 
 static int
-compare_start(int *x, int *y) {
+compare_start(struct fdisk_context *cxt, const void *x, const void *y) {
 	/*
 	 * sort according to start sectors
 	 * and prefers largest partition:
 	 * entry zero is entire disk entry
 	 */
-	unsigned int i = *x;
-	unsigned int j = *y;
-	unsigned int a = sgi_get_start_sector(i);
-	unsigned int b = sgi_get_start_sector(j);
-	unsigned int c = sgi_get_num_sectors(i);
-	unsigned int d = sgi_get_num_sectors(j);
+	unsigned int i = *(int *) x;
+	unsigned int j = *(int *) y;
+	unsigned int a = sgi_get_start_sector(cxt, i);
+	unsigned int b = sgi_get_start_sector(cxt, j);
+	unsigned int c = sgi_get_num_sectors(cxt, i);
+	unsigned int d = sgi_get_num_sectors(cxt, j);
 
 	if (a == b)
 		return (d > c) ? 1 : (d == c) ? 0 : -1;
@@ -397,18 +401,67 @@ compare_start(int *x, int *y) {
 }
 
 static int
-sgi_gaps(void) {
+sgi_gaps(struct fdisk_context *cxt) {
 	/*
 	 * returned value is:
 	 *  = 0 : disk is properly filled to the rim
 	 *  < 0 : there is an overlap
 	 *  > 0 : there is still some vacant space
 	 */
-	return verify_sgi(0);
+	return verify_sgi(cxt, 0);
 }
 
+static void generic_swap(void *a, void *b, int size)
+{
+	char t;
+
+	do {
+		t = *(char *)a;
+		*(char *)a++ = *(char *)b;
+		*(char *)b++ = t;
+	} while (--size > 0);
+}
+
+
+/* heap sort, based on Matt Mackall's linux kernel version */
+static void sort(void *base, size_t num, size_t size, struct fdisk_context *cxt,
+		 int (*cmp_func)(struct fdisk_context *, const void *, const void *))
+{
+	/* pre-scale counters for performance */
+	int i = (num/2 - 1) * size;
+	size_t n = num * size, c, r;
+
+	/* heapify */
+	for ( ; i >= 0; i -= size) {
+		for (r = i; r * 2 + size < n; r  = c) {
+			c = r * 2 + size;
+			if (c < n - size &&
+			    cmp_func(cxt, base + c, base + c + size) < 0)
+				c += size;
+			if (cmp_func(cxt, base + r, base + c) >= 0)
+				break;
+			generic_swap(base + r, base + c, size);
+		}
+	}
+
+	/* sort */
+	for (i = n - size; i > 0; i -= size) {
+		generic_swap(base, base + i, size);
+		for (r = 0; r * 2 + size < (size_t) i; r = c) {
+			c = r * 2 + size;
+			if (c < i - size &&
+			    cmp_func(cxt, base + c, base + c + size) < 0)
+				c += size;
+			if (cmp_func(cxt, base + r, base + c) >= 0)
+				break;
+			generic_swap(base + r, base + c, size);
+		}
+	}
+}
+
+
 int
-verify_sgi(int verbose)
+verify_sgi(struct fdisk_context *cxt, int verbose)
 {
 	int Index[16];		/* list of valid partitions */
 	int sortcount = 0;	/* number of used partitions, i.e. non-zero lengths */
@@ -419,9 +472,9 @@ verify_sgi(int verbose)
 
 	clearfreelist();
 	for (i=0; i<16; i++) {
-		if (sgi_get_num_sectors(i) != 0) {
+		if (sgi_get_num_sectors(cxt, i) != 0) {
 			Index[sortcount++]=i;
-			if (sgi_get_sysid(i) == ENTIRE_DISK) {
+			if (sgi_get_sysid(cxt, i) == ENTIRE_DISK) {
 				if (entire++ == 1) {
 					if (verbose)
 						printf(_("More than one entire disk entry present.\n"));
@@ -434,71 +487,73 @@ verify_sgi(int verbose)
 			printf(_("No partitions defined\n"));
 		return (lastblock > 0) ? 1 : (lastblock == 0) ? 0 : -1;
 	}
-	qsort(Index, sortcount, sizeof(Index[0]), (void*)compare_start);
-	if (sgi_get_sysid(Index[0]) == ENTIRE_DISK) {
+
+	sort(Index, sortcount, sizeof(Index[0]), cxt, compare_start);
+
+	if (sgi_get_sysid(cxt, Index[0]) == ENTIRE_DISK) {
 		if ((Index[0] != 10) && verbose)
 			printf(_("IRIX likes when Partition 11 covers the entire disk.\n"));
-		if ((sgi_get_start_sector(Index[0]) != 0) && verbose)
+		if ((sgi_get_start_sector(cxt, Index[0]) != 0) && verbose)
 			printf(_("The entire disk partition should start "
 				 "at block 0,\n"
 				 "not at diskblock %d.\n"),
-			       sgi_get_start_sector(Index[0]));
+			       sgi_get_start_sector(cxt, Index[0]));
 		if (debug)	/* I do not understand how some disks fulfil it */
-			if ((sgi_get_num_sectors(Index[0]) != lastblock) && verbose)
+			if ((sgi_get_num_sectors(cxt, Index[0]) != lastblock) && verbose)
 				printf(_("The entire disk partition is only %d diskblock large,\n"
 					 "but the disk is %d diskblocks long.\n"),
-				       sgi_get_num_sectors(Index[0]), lastblock);
-		lastblock = sgi_get_num_sectors(Index[0]);
+				       sgi_get_num_sectors(cxt, Index[0]), lastblock);
+		lastblock = sgi_get_num_sectors(cxt, Index[0]);
 	} else {
 		if (verbose)
 			printf(_("Partition 11 should cover the entire disk.\n"));
 		if (debug>2)
 			printf("sysid=%d\tpartition=%d\n",
-			       sgi_get_sysid(Index[0]), Index[0]+1);
+			       sgi_get_sysid(cxt, Index[0]), Index[0]+1);
 	}
 	for (i=1, start=0; i<sortcount; i++) {
-		int cylsize = sgi_get_nsect() * sgi_get_ntrks();
-		if ((sgi_get_start_sector(Index[i]) % cylsize) != 0) {
+		int cylsize = sgi_get_nsect(cxt) * sgi_get_ntrks(cxt);
+		if ((sgi_get_start_sector(cxt, Index[i]) % cylsize) != 0) {
 			if (debug)	/* I do not understand how some disks fulfil it */
 				if (verbose)
 					printf(_("Partition %d does not start on cylinder boundary.\n"),
 					       Index[i]+1);
 		}
-		if (sgi_get_num_sectors(Index[i]) % cylsize != 0) {
+		if (sgi_get_num_sectors(cxt, Index[i]) % cylsize != 0) {
 			if (debug)	/* I do not understand how some disks fulfil it */
 				if (verbose)
 					printf(_("Partition %d does not end on cylinder boundary.\n"),
 					       Index[i]+1);
 		}
 		/* We cannot handle several "entire disk" entries. */
-		if (sgi_get_sysid(Index[i]) == ENTIRE_DISK) continue;
-		if (start > sgi_get_start_sector(Index[i])) {
+		if (sgi_get_sysid(cxt, Index[i]) == ENTIRE_DISK) continue;
+		if (start > sgi_get_start_sector(cxt, Index[i])) {
 			if (verbose)
 				printf(_("The Partition %d and %d overlap by %d sectors.\n"),
 				       Index[i-1]+1, Index[i]+1,
-				       start - sgi_get_start_sector(Index[i]));
+				       start - sgi_get_start_sector(cxt, Index[i]));
 			if (gap >  0) gap = -gap;
 			if (gap == 0) gap = -1;
 		}
-		if (start < sgi_get_start_sector(Index[i])) {
+		if (start < sgi_get_start_sector(cxt, Index[i])) {
 			if (verbose)
 				printf(_("Unused gap of %8u sectors - sectors %8u-%u\n"),
-				       sgi_get_start_sector(Index[i]) - start,
-				       start, sgi_get_start_sector(Index[i])-1);
-			gap += sgi_get_start_sector(Index[i]) - start;
-			add2freelist(start, sgi_get_start_sector(Index[i]));
+				       sgi_get_start_sector(cxt, Index[i]) - start,
+				       start, sgi_get_start_sector(cxt, Index[i])-1);
+			gap += sgi_get_start_sector(cxt, Index[i]) - start;
+			add2freelist(start, sgi_get_start_sector(cxt, Index[i]));
 		}
-		start = sgi_get_start_sector(Index[i])
-			+ sgi_get_num_sectors(Index[i]);
+		start = sgi_get_start_sector(cxt, Index[i])
+			+ sgi_get_num_sectors(cxt, Index[i]);
 		/* Align free space on cylinder boundary */
 		if (start % cylsize)
 			start += cylsize - (start % cylsize);
 		if (debug > 1) {
 			if (verbose)
 				printf("%2d:%12d\t%12d\t%12d\n", Index[i],
-				       sgi_get_start_sector(Index[i]),
-				       sgi_get_num_sectors(Index[i]),
-				       sgi_get_sysid(Index[i]));
+				       sgi_get_start_sector(cxt, Index[i]),
+				       sgi_get_num_sectors(cxt, Index[i]),
+				       sgi_get_sysid(cxt, Index[i]));
 		}
 	}
 	if (start < lastblock) {
@@ -513,31 +568,31 @@ verify_sgi(int verbose)
 	 * Go for details now
 	 */
 	if (verbose) {
-		if (sgi_get_bootpartition() < 0 || !sgi_get_num_sectors(sgi_get_bootpartition())) {
+		if (sgi_get_bootpartition(cxt) < 0 || !sgi_get_num_sectors(cxt, sgi_get_bootpartition(cxt))) {
 			printf(_("\nThe boot partition does not exist.\n"));
 		}
-		if (sgi_get_swappartition() < 0 || !sgi_get_num_sectors(sgi_get_swappartition())) {
+		if (sgi_get_swappartition(cxt) < 0 || !sgi_get_num_sectors(cxt, sgi_get_swappartition(cxt))) {
 			printf(_("\nThe swap partition does not exist.\n"));
 		} else {
-			if ((sgi_get_sysid(sgi_get_swappartition()) != SGI_SWAP)
-			    &&  (sgi_get_sysid(sgi_get_swappartition()) != LINUX_SWAP))
+			if ((sgi_get_sysid(cxt, sgi_get_swappartition(cxt)) != SGI_SWAP)
+			    &&  (sgi_get_sysid(cxt, sgi_get_swappartition(cxt)) != LINUX_SWAP))
 				printf(_("\nThe swap partition has no swap type.\n"));
 		}
-		if (sgi_check_bootfile("/unix"))
+		if (sgi_check_bootfile(cxt, "/unix"))
 			printf(_("\tYou have chosen an unusual boot file name.\n"));
 	}
 	return (gap > 0) ? 1 : (gap == 0) ? 0 : -1;
 }
 
 int
-sgi_change_sysid(int i, int sys)
+sgi_change_sysid(struct fdisk_context *cxt, int i, int sys)
 {
-	if (sgi_get_num_sectors(i) == 0) /* caught already before, ... */ {
+	if (sgi_get_num_sectors(cxt, i) == 0) /* caught already before, ... */ {
 		printf(_("Sorry, only for non-empty partitions you can change the tag.\n"));
 		return 0;
 	}
 	if (((sys != ENTIRE_DISK) && (sys != SGI_VOLHDR))
-	    && (sgi_get_start_sector(i)<1)) {
+	    && (sgi_get_start_sector(cxt, i)<1)) {
 		read_chars(
 			_("It is highly recommended that the partition at offset 0\n"
 			  "is of type \"SGI volhdr\", the IRIX system will rely on it to\n"
@@ -553,11 +608,11 @@ sgi_change_sysid(int i, int sys)
 
 /* returns partition index of first entry marked as entire disk */
 static int
-sgi_entire(void) {
+sgi_entire(struct fdisk_context *cxt) {
 	int i;
 
 	for (i=0; i<16; i++)
-		if (sgi_get_sysid(i) == SGI_VOLUME)
+		if (sgi_get_sysid(cxt, i) == SGI_VOLUME)
 			return i;
 	return -1;
 }
@@ -569,7 +624,7 @@ sgi_set_partition(struct fdisk_context *cxt,
 	sgilabel->partitions[i].num_sectors = SSWAP32(length);
 	sgilabel->partitions[i].start_sector = SSWAP32(start);
 	set_changed(i);
-	if (sgi_gaps() < 0)	/* rebuild freelist */
+	if (sgi_gaps(cxt) < 0)	/* rebuild freelist */
 		printf(_("Partition overlap on the disk.\n"));
 	if (length)
 		print_partition_size(cxt, i + 1, start, start + length, sys);
@@ -580,7 +635,7 @@ sgi_set_entire(struct fdisk_context *cxt) {
 	int n;
 
 	for (n=10; n<partitions; n++) {
-		if (!sgi_get_num_sectors(n)) {
+		if (!sgi_get_num_sectors(cxt, n)) {
 			sgi_set_partition(cxt, n, 0, sgi_get_lastblock(), SGI_VOLUME);
 			break;
 		}
@@ -594,7 +649,7 @@ sgi_set_volhdr(struct fdisk_context *cxt)
 	int n;
 
 	for (n=8; n<partitions; n++) {
-		if (!sgi_get_num_sectors(n)) {
+		if (!sgi_get_num_sectors(cxt, n)) {
 			/*
 			 * Choose same default volume header size
 			 * as IRIX fx uses.
@@ -623,22 +678,22 @@ sgi_add_partition(struct fdisk_context *cxt, int n, int sys)
 	} else if (n == 8) {
 		sys = 0;
 	}
-	if (sgi_get_num_sectors(n)) {
+	if (sgi_get_num_sectors(cxt, n)) {
 		printf(_("Partition %d is already defined.  Delete "
 			 "it before re-adding it.\n"), n + 1);
 		return;
 	}
-	if ((sgi_entire() == -1)
+	if ((sgi_entire(cxt) == -1)
 	    &&  (sys != SGI_VOLUME)) {
 		printf(_("Attempting to generate entire disk entry automatically.\n"));
 		sgi_set_entire(cxt);
 		sgi_set_volhdr(cxt);
 	}
-	if ((sgi_gaps() == 0) &&  (sys != SGI_VOLUME)) {
+	if ((sgi_gaps(cxt) == 0) &&  (sys != SGI_VOLUME)) {
 		printf(_("The entire disk is already covered with partitions.\n"));
 		return;
 	}
-	if (sgi_gaps() < 0) {
+	if (sgi_gaps(cxt) < 0) {
 		printf(_("You got a partition overlap on the disk. Fix it first!\n"));
 		return;
 	}
@@ -730,7 +785,7 @@ create_sgilabel(struct fdisk_context *cxt)
 #endif
 	for (i = 0; i < 4; i++) {
 		old[i].sysid = 0;
-		if (valid_part_table_flag(MBRbuffer)) {
+		if (valid_part_table_flag(cxt->mbr)) {
 			if (get_part_table(i)->sys_ind) {
 				old[i].sysid = get_part_table(i)->sys_ind;
 				old[i].start = get_start_sect(get_part_table(i));
@@ -748,7 +803,7 @@ create_sgilabel(struct fdisk_context *cxt)
 			break;
 		}
 
-	zeroize_mbr_buffer();
+	fdisk_mbr_zeroize(cxt);
 	sgilabel->magic = SSWAP32(SGI_LABEL_MAGIC);
 	sgilabel->boot_part = SSWAP16(0);
 	sgilabel->swap_part = SSWAP16(1);
diff --git a/fdisk/fdisksgilabel.h b/fdisk/fdisksgilabel.h
index 7611d327a..dff32b1ec 100644
--- a/fdisk/fdisksgilabel.h
+++ b/fdisk/fdisksgilabel.h
@@ -106,33 +106,33 @@ typedef struct {
 #define SSWAP32(x) (other_endian ? swab32(x) : (uint32_t)(x))
 
 /* fdisk.c */
-#define sgilabel ((sgi_partition *)MBRbuffer)
+#define sgilabel ((sgi_partition *)cxt->mbr)
 #define sgiparam (sgilabel->devparam)
 
 /* fdisksgilabel.c */
 extern struct	systypes sgi_sys_types[];
-extern void	sgi_nolabel( void );
-extern int	check_sgi_label( void );
+extern void	sgi_nolabel(struct fdisk_context *cxt);
+extern int	check_sgi_label(struct fdisk_context *cxt);
 extern void	sgi_list_table( struct fdisk_context *cxt, int xtra );
-extern int  sgi_change_sysid( int i, int sys );
-extern unsigned int	sgi_get_start_sector( int i );
-extern unsigned int	sgi_get_num_sectors( int i );
-extern int	sgi_get_sysid( int i );
+extern int  sgi_change_sysid(struct fdisk_context *cxt, int i, int sys);
+extern unsigned int	sgi_get_start_sector(struct fdisk_context *cxt, int i );
+extern unsigned int	sgi_get_num_sectors(struct fdisk_context *cxt, int i );
+extern int	sgi_get_sysid(struct fdisk_context *cxt, int i );
 extern void	sgi_delete_partition( struct fdisk_context *cxt, int i );
 extern void	sgi_add_partition( struct fdisk_context *cxt, int n, int sys );
 extern void	create_sgilabel( struct fdisk_context *cxt );
-extern void	create_sgiinfo( void );
-extern int	verify_sgi( int verbose );
+extern void	create_sgiinfo(struct fdisk_context *cxt);
+extern int	verify_sgi(struct fdisk_context *cxt, int verbose );
 extern void	sgi_write_table( struct fdisk_context *cxt );
 extern void	sgi_set_ilfact( void );
 extern void	sgi_set_rspeed( void );
 extern void	sgi_set_pcylcount( void );
 extern void	sgi_set_xcyl( void );
 extern void	sgi_set_ncyl( void );
-extern void	sgi_set_bootpartition( int i );
-extern void	sgi_set_swappartition( int i );
-extern int	sgi_get_bootpartition( void );
-extern int	sgi_get_swappartition( void );
-extern void	sgi_set_bootfile(void);
+extern void	sgi_set_bootpartition(struct fdisk_context *cxt, int i );
+extern void	sgi_set_swappartition(struct fdisk_context *cxt, int i );
+extern int	sgi_get_bootpartition(struct fdisk_context *cxt);
+extern int	sgi_get_swappartition(struct fdisk_context *cxt);
+extern void	sgi_set_bootfile(struct fdisk_context *cxt);
 
 #endif /* FDISK_SGI_LABEL_H */
diff --git a/fdisk/fdisksunlabel.c b/fdisk/fdisksunlabel.c
index ae24e1611..d80b039b0 100644
--- a/fdisk/fdisksunlabel.c
+++ b/fdisk/fdisksunlabel.c
@@ -78,13 +78,13 @@ static void init(void)
 	partitions = SUN_NUM_PARTITIONS;
 }
 
-void sun_nolabel(void)
+void sun_nolabel(struct fdisk_context *cxt)
 {
 	sunlabel->magic = 0;
 	partitions = 4;
 }
 
-int check_sun_label(void)
+int check_sun_label(struct fdisk_context *cxt)
 {
 	unsigned short *ush;
 	int csum;
@@ -166,7 +166,7 @@ void create_sunlabel(struct fdisk_context *cxt)
 #endif
 
 	init();
-	zeroize_mbr_buffer();
+	fdisk_mbr_zeroize(cxt);
 
 	sunlabel->magic = SSWAP16(SUN_LABEL_MAGIC);
 	sunlabel->sanity = SSWAP32(SUN_LABEL_SANE);
@@ -242,7 +242,7 @@ void create_sunlabel(struct fdisk_context *cxt)
 	set_changed(0);
 }
 
-void toggle_sunflags(int i, uint16_t mask)
+void toggle_sunflags(struct fdisk_context *cxt, int i, uint16_t mask)
 {
 	struct sun_tag_flag *p = &sunlabel->part_tags[i];
 
@@ -251,7 +251,8 @@ void toggle_sunflags(int i, uint16_t mask)
 	set_changed(i);
 }
 
-static void fetch_sun(uint32_t *starts, uint32_t *lens, uint32_t *start, uint32_t *stop)
+static void fetch_sun(struct fdisk_context *cxt, uint32_t *starts,
+		      uint32_t *lens, uint32_t *start, uint32_t *stop)
 {
 	int i, continuous = 1;
 
@@ -298,7 +299,7 @@ static int verify_sun_cmp(int *a, int *b)
     return -1;
 }
 
-void verify_sun(void)
+void verify_sun(struct fdisk_context *cxt)
 {
     uint32_t starts[SUN_NUM_PARTITIONS], lens[SUN_NUM_PARTITIONS], start, stop;
     uint32_t i,j,k,starto,endo;
@@ -306,7 +307,7 @@ void verify_sun(void)
 
     verify_sun_starts = starts;
 
-    fetch_sun(starts, lens, &start, &stop);
+    fetch_sun(cxt, starts, lens, &start, &stop);
 
     for (k = 0; k < 7; k++) {
 	for (i = 0; i < SUN_NUM_PARTITIONS; i++) {
@@ -347,6 +348,7 @@ void verify_sun(void)
     }
     qsort(array,ARRAY_SIZE(array),sizeof(array[0]),
 	  (int (*)(const void *,const void *)) verify_sun_cmp);
+
     if (array[0] == -1) {
     	printf(_("No partitions defined\n"));
     	return;
@@ -382,7 +384,7 @@ void add_sun_partition(struct fdisk_context *cxt, int n, int sys)
 		return;
 	}
 	
-	fetch_sun(starts, lens, &start, &stop);
+	fetch_sun(cxt, starts, lens, &start, &stop);
 	if (stop <= start) {
 		if (n == 2)
 			whole_disk = 1;
@@ -484,7 +486,7 @@ and is of type `Whole disk'\n"));
 	set_sun_partition(cxt, n, first, last, sys);
 }
 
-void sun_delete_partition(int i)
+void sun_delete_partition(struct fdisk_context *cxt, int i)
 {
 	struct sun_partition *part = &sunlabel->partitions[i];
 	struct sun_tag_flag *tag = &sunlabel->part_tags[i];
@@ -503,7 +505,7 @@ void sun_delete_partition(int i)
 	part->num_sectors = 0;
 }
 
-int sun_change_sysid(int i, uint16_t sys)
+int sun_change_sysid(struct fdisk_context *cxt, int i, uint16_t sys)
 {
 	struct sun_partition *part = &sunlabel->partitions[i];
 	struct sun_tag_flag *tag = &sunlabel->part_tags[i];
@@ -594,7 +596,7 @@ void sun_set_alt_cyl(struct fdisk_context *cxt)
 				 _("Number of alternate cylinders")));
 }
 
-void sun_set_ncyl(int cyl)
+void sun_set_ncyl(struct fdisk_context *cxt, int cyl)
 {
 	sunlabel->ncyl = SSWAP16(cyl);
 }
@@ -641,7 +643,7 @@ void sun_write_table(struct fdisk_context *cxt)
 		fatal(cxt, unable_to_write);
 }
 
-int sun_get_sysid(int i)
+int sun_get_sysid(struct fdisk_context *cxt, int i)
 {
 	return SSWAP16(sunlabel->part_tags[i].tag);
 }
diff --git a/fdisk/fdisksunlabel.h b/fdisk/fdisksunlabel.h
index 8cb13ec17..d3cd43016 100644
--- a/fdisk/fdisksunlabel.h
+++ b/fdisk/fdisksunlabel.h
@@ -73,26 +73,26 @@ struct sun_disk_label {
 
 #define SUN_LABEL_MAGIC		0xDABE
 #define SUN_LABEL_MAGIC_SWAPPED	0xBEDA
-#define sunlabel ((struct sun_disk_label *)MBRbuffer)
+#define sunlabel ((struct sun_disk_label *)cxt->mbr)
 
 /* fdisksunlabel.c */
 extern struct systypes sun_sys_types[];
-extern int check_sun_label(void);
-extern void sun_nolabel(void);
+extern int check_sun_label(struct fdisk_context *cxt);
+extern void sun_nolabel(struct fdisk_context *cxt);
 extern void create_sunlabel(struct fdisk_context *cxt);
-extern void sun_delete_partition(int i);
-extern int sun_change_sysid(int i, uint16_t sys);
+extern void sun_delete_partition(struct fdisk_context *cxt, int i);
+extern int sun_change_sysid(struct fdisk_context *cxt, int i, uint16_t sys);
 extern void sun_list_table(struct fdisk_context *cxt, int xtra);
-extern void verify_sun(void);
+extern void verify_sun(struct fdisk_context *cxt);
 extern void add_sun_partition(struct fdisk_context *cxt, int n, int sys);
 extern void sun_write_table(struct fdisk_context *cxt);
 extern void sun_set_alt_cyl(struct fdisk_context *cxt);
-extern void sun_set_ncyl(int cyl);
+extern void sun_set_ncyl(struct fdisk_context *cxt, int cyl);
 extern void sun_set_xcyl(struct fdisk_context *cxt);
 extern void sun_set_ilfact(struct fdisk_context *cxt);
 extern void sun_set_rspeed(struct fdisk_context *cxt);
 extern void sun_set_pcylcount(struct fdisk_context *cxt);
-extern void toggle_sunflags(int i, uint16_t mask);
-extern int sun_get_sysid(int i);
+extern void toggle_sunflags(struct fdisk_context *cxt, int i, uint16_t mask);
+extern int sun_get_sysid(struct fdisk_context *cxt, int i);
 
 #endif /* FDISK_SUN_LABEL_H */
diff --git a/fdisk/utils.c b/fdisk/utils.c
index d105d8e42..616fcc0dd 100644
--- a/fdisk/utils.c
+++ b/fdisk/utils.c
@@ -31,6 +31,21 @@
 
 int fdisk_debug_mask;
 
+static int __init_mbr_buffer(struct fdisk_context *cxt)
+{
+	cxt->mbr = calloc(1, MAX_SECTOR_SIZE);
+	if (!cxt->mbr)
+		goto fail;
+
+	/* read MBR */
+	if (512 != read(cxt->dev_fd, cxt->mbr, 512))
+		goto fail;
+
+	return 0;
+fail:
+	return -1;
+}
+
 static unsigned long __get_sector_size(int fd)
 {
 	int sect_sz;
@@ -93,6 +108,18 @@ static int __discover_topology(struct fdisk_context *cxt)
 	return 0;
 }
 
+/**
+ * fdisk_mbr_zeroize:
+ * @cxt: fdisk context
+ *
+ * Zero's MBR buffer
+ */
+void fdisk_mbr_zeroize(struct fdisk_context *cxt)
+{
+	if (cxt->mbr)
+		bzero(cxt->mbr, MAX_SECTOR_SIZE);
+}
+
 /**
  * fdisk_dev_sectsz_is_default:
  * @cxt: fdisk context
@@ -181,6 +208,9 @@ struct fdisk_context *fdisk_new_context_from_filename(const char *fname, int rea
 	if (!cxt->dev_path)
 		goto fail;
 
+	if (__init_mbr_buffer(cxt) < 0)
+		goto fail;
+
 	__discover_topology(cxt);
 	__discover_geometry(cxt);
 
@@ -210,5 +240,6 @@ void fdisk_free_context(struct fdisk_context *cxt)
 	DBG(CONTEXT, dbgprint("freeing context for %s", cxt->dev_path));
 	close(cxt->dev_fd);
 	free(cxt->dev_path);
+	free(cxt->mbr);
 	free(cxt);
 }