disk: part_dos: Align dos_partition_t with struct partition

The dos_partition_t struct defined in part_dos.h is nearly identical to
the struct partition defined in part_efi.h. They differ primarily in how
define their starting sector and number of sectors fields.

The former uses unsigned char arrays while the latter uses __le32 types.
Using __le32 is preferable, as it removes the ambiguity and potential
misuse of a raw byte array. This also aligns the structure with how the
Linux kernel defines it nowadays, which is the original source of it.

To prepare for future consolidation where one of the data structures can
be removed, this change aligns both definitions and updates all accessors
for dos_partition_t.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

diff --git a/disk/part_dos.c b/disk/part_dos.c
index 2545cc6bf5d2f8ea647d450a5ce9e480f6d4f1ac..60c3d677369662a2d6f08db2c4beaf7c57f333d9 100644 (file)
--- a/disk/part_dos.c
+++ b/disk/part_dos.c
@@ -49,8 +49,8 @@ static int get_bootable(dos_partition_t *p)
 static void print_one_part(dos_partition_t *p, lbaint_t ext_part_sector,
                           int part_num, unsigned int disksig)
 {
-       lbaint_t lba_start = ext_part_sector + get_unaligned_le32(p->start4);
-       lbaint_t lba_size  = get_unaligned_le32(p->size4);
+       lbaint_t lba_start = ext_part_sector + get_unaligned_le32(&p->start_sect);
+       lbaint_t lba_size  = get_unaligned_le32(&p->nr_sects);
 
        printf("%3d\t%-10" LBAFlength "u\t%-10" LBAFlength
                "u\t%08x-%02x\t%02x%s%s\n",
@@ -185,7 +185,7 @@ static void print_partition_extended(struct blk_desc *desc,
        for (i = 0; i < 4; i++, pt++) {
                if (is_extended (pt->sys_ind)) {
                        lbaint_t lba_start
-                               = get_unaligned_le32 (pt->start4) + relative;
+                               = get_unaligned_le32 (&pt->start_sect) + relative;
 
                        print_partition_extended(desc, lba_start,
                                                 !ext_part_sector ? lba_start :
@@ -252,8 +252,8 @@ static int part_get_info_extended(struct blk_desc *desc,
                        else
                                info->blksz = DOS_PART_DEFAULT_SECTOR;
                        info->start = (lbaint_t)(ext_part_sector +
-                                       get_unaligned_le32(pt->start4));
-                       info->size  = (lbaint_t)get_unaligned_le32(pt->size4);
+                                       get_unaligned_le32(&pt->start_sect));
+                       info->size  = (lbaint_t)get_unaligned_le32(&pt->nr_sects);
                        part_set_generic_name(desc, part_num,
                                              (char *)info->name);
                        /* sprintf(info->type, "%d, pt->sys_ind); */
@@ -281,7 +281,7 @@ static int part_get_info_extended(struct blk_desc *desc,
        for (i = 0; i < 4; i++, pt++) {
                if (is_extended (pt->sys_ind)) {
                        lbaint_t lba_start
-                               = get_unaligned_le32 (pt->start4) + relative;
+                               = get_unaligned_le32 (&pt->start_sect) + relative;
 
                        return part_get_info_extended(desc, lba_start,
                                 ext_part_sector == 0 ? lba_start : relative,
@@ -356,8 +356,8 @@ static void mbr_fill_pt_entry(dos_partition_t *pt, lbaint_t start,
        pt->sys_ind = sys_ind;
        lba_to_chs(start, &pt->cyl, &pt->head, &pt->sector);
        lba_to_chs(start + size - 1, &pt->end_cyl, &pt->end_head, &pt->end_sector);
-       put_unaligned_le32(relative, &pt->start4);
-       put_unaligned_le32(size, &pt->size4);
+       put_unaligned_le32(relative, &pt->start_sect);
+       put_unaligned_le32(size, &pt->nr_sects);
 }
 
 int write_mbr_partitions(struct blk_desc *dev,

diff --git a/include/part_dos.h b/include/part_dos.h
index 505582242281afa66df27fd3cf8263aa0caa6a38..92956d53063732389aa257f4b611d9eb16b20b23 100644 (file)
--- a/include/part_dos.h
+++ b/include/part_dos.h
@@ -30,8 +30,8 @@ typedef struct dos_partition {
        unsigned char end_head;         /* end head                             */
        unsigned char end_sector;       /* end sector                           */
        unsigned char end_cyl;          /* end cylinder                         */
-       unsigned char start4[4];        /* starting sector counting from 0      */
-       unsigned char size4[4];         /* nr of sectors in partition           */
-} dos_partition_t;
+       __le32 start_sect;              /* starting sector counting from 0      */
+       __le32 nr_sects;                /* nr of sectors in partition           */
+} __packed dos_partition_t;
 
 #endif /* _DISK_PART_DOS_H */