ext4-mbr-write: Fixed partition size calculation

[lwext4.git] / src / ext4_mbr.c

diff --git a/src/ext4_mbr.c b/src/ext4_mbr.c
index 52df852a608c53001ddb947d424ef2c4e5338f0a..14fe252f1ac53ab69c29f990a3646ae2df601b8b 100644 (file)
--- a/src/ext4_mbr.c
+++ b/src/ext4_mbr.c
@@ -34,10 +34,13 @@
  * @brief Master boot record parser
  */
 
-#include "ext4_config.h"
-#include "ext4_types.h"
-#include "ext4_debug.h"
-#include "ext4_mbr.h"
+#include <ext4_config.h>
+#include <ext4_types.h>
+#include <ext4_misc.h>
+#include <ext4_errno.h>
+#include <ext4_debug.h>
+
+#include <ext4_mbr.h>
 
 #include <inttypes.h>
 #include <string.h>
@@ -123,6 +126,80 @@ int ext4_mbr_scan(struct ext4_blockdev *parent, struct ext4_mbr_bdevs *bdevs)
        return r;
 }
 
+int ext4_mbr_write(struct ext4_blockdev *parent, struct ext4_mbr_parts *parts)
+{
+       int r;
+       uint64_t disk_size;
+       uint32_t division_sum = parts->division[0] + parts->division[1] +
+                               parts->division[2] + parts->division[3];
+
+       if (division_sum > 100)
+               return EINVAL;
+
+       ext4_dbg(DEBUG_MBR, DBG_INFO "ext4_mbr_write\n");
+       r = ext4_block_init(parent);
+       if (r != EOK)
+               return r;
+
+       disk_size = parent->part_size;
+
+       /*Calculate CHS*/
+       uint32_t k = 16;
+       while ((k < 256) && ((disk_size / k / 63) > 1024))
+               k *= 2;
+
+       if (k == 256)
+               --k;
+
+       const uint32_t cyl_size = 63 * k;
+       const uint32_t cyl_count = disk_size / cyl_size;
+
+       struct ext4_mbr *mbr = (void *)parent->bdif->ph_bbuf;
+       memset(mbr, 0, sizeof(struct ext4_mbr));
+
+
+       uint32_t cyl_it = 0;
+       for (int i = 0; i < 4; ++i) {
+               uint32_t cyl_part = cyl_count * parts->division[i] / 100;
+               if (!cyl_part)
+                       continue;
+
+               uint32_t part_start = cyl_it * cyl_size;
+               uint32_t part_size = cyl_part * cyl_size;
+
+               if (i == 0) {
+                       part_start += 63;
+                       part_size -= 63 * parent->bdif->ph_bsize;
+               }
+
+               uint32_t cyl_end = cyl_part + cyl_it - 1;
+
+               mbr->part_entry[i].status = 0;
+               mbr->part_entry[i].chs1[0] = i ? 0 : 1;;
+               mbr->part_entry[i].chs1[1] = (cyl_it >> 2) + 1;
+               mbr->part_entry[i].chs1[2] = cyl_it;
+               mbr->part_entry[i].type = 0x83;
+               mbr->part_entry[i].chs2[0] = k - 1;
+               mbr->part_entry[i].chs2[1] = (cyl_end >> 2) + 63;
+               mbr->part_entry[i].chs2[2] = cyl_end;
+
+               mbr->part_entry[i].first_lba = part_start;
+               mbr->part_entry[i].sectors = part_size / parent->bdif->ph_bsize;
+
+               cyl_it += cyl_part;
+       }
+
+       mbr->signature = MBR_SIGNATURE;
+       r = ext4_block_writebytes(parent, 0, parent->bdif->ph_bbuf, 512);
+       if (r != EOK)
+               goto blockdev_fini;
+
+
+       blockdev_fini:
+       ext4_block_fini(parent);
+       return r;
+}
+
 /**
  * @}
  */