fdisk: API: add mbr

This patch adds to the fdisk API the relevant logic to buffers that have MBR. This also serves for
future GPT support for the protective MBR. All labels have been updated to have access to the cxt
structure for the corresponding buffer.

An important observation is that SGI no longer uses the standard qsort(3) function to sort partitions,
as it needs access to cxt. To address this, a heap sort implementation from the kernel was added to
the label code and adapted to fdisk.

Signed-off-by: Davidlohr Bueso <dave@gnu.org>

1 files changed, 28 insertions, 55 deletions

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 :
@@ -556,27 +556,6 @@ 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)
  *    0: found or created label
@@ -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;