diff options
Diffstat (limited to '')
| -rw-r--r-- | exfat/mkfs/vbr.c | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/exfat/mkfs/vbr.c b/exfat/mkfs/vbr.c new file mode 100644 index 000000000..bbf1304d9 --- /dev/null +++ b/exfat/mkfs/vbr.c @@ -0,0 +1,148 @@ +/* + vbr.c (09.11.10) + Volume Boot Record creation code. + + Free exFAT implementation. + Copyright (C) 2011-2013 Andrew Nayenko + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License along + with this program; if not, write to the Free Software Foundation, Inc., + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. +*/ + +#include <string.h> +#include "vbr.h" +#include "fat.h" +#include "cbm.h" +#include "uct.h" +#include "rootdir.h" + +static off64_t vbr_alignment(void) +{ + return get_sector_size(); +} + +static off64_t vbr_size(void) +{ + return 12 * get_sector_size(); +} + +static void init_sb(struct exfat_super_block* sb) +{ + uint32_t clusters_max; + uint32_t fat_sectors; + + clusters_max = get_volume_size() / get_cluster_size(); + fat_sectors = DIV_ROUND_UP((off64_t) clusters_max * sizeof(cluster_t), + get_sector_size()); + + memset(sb, 0, sizeof(struct exfat_super_block)); + sb->jump[0] = 0xeb; + sb->jump[1] = 0x76; + sb->jump[2] = 0x90; + memcpy(sb->oem_name, "EXFAT ", sizeof(sb->oem_name)); + sb->sector_start = cpu_to_le64(get_first_sector()); + sb->sector_count = cpu_to_le64(get_volume_size() / get_sector_size()); + sb->fat_sector_start = cpu_to_le32( + fat.get_alignment() / get_sector_size()); + sb->fat_sector_count = cpu_to_le32(ROUND_UP( + le32_to_cpu(sb->fat_sector_start) + fat_sectors, + 1 << get_spc_bits()) - + le32_to_cpu(sb->fat_sector_start)); + sb->cluster_sector_start = cpu_to_le32( + get_position(&cbm) / get_sector_size()); + sb->cluster_count = cpu_to_le32(clusters_max - + ((le32_to_cpu(sb->fat_sector_start) + + le32_to_cpu(sb->fat_sector_count)) >> get_spc_bits())); + sb->rootdir_cluster = cpu_to_le32( + (get_position(&rootdir) - get_position(&cbm)) / get_cluster_size() + + EXFAT_FIRST_DATA_CLUSTER); + sb->volume_serial = cpu_to_le32(get_volume_serial()); + sb->version.major = 1; + sb->version.minor = 0; + sb->volume_state = cpu_to_le16(0); + sb->sector_bits = get_sector_bits(); + sb->spc_bits = get_spc_bits(); + sb->fat_count = 1; + sb->drive_no = 0x80; + sb->allocated_percent = 0; + sb->boot_signature = cpu_to_le16(0xaa55); +} + +static int vbr_write(struct exfat_dev* dev) +{ + struct exfat_super_block sb; + uint32_t checksum; + le32_t* sector = malloc(get_sector_size()); + size_t i; + + if (sector == NULL) + { + exfat_error("failed to allocate sector-sized block of memory"); + return 1; + } + + init_sb(&sb); + if (exfat_write(dev, &sb, sizeof(struct exfat_super_block)) < 0) + { + free(sector); + exfat_error("failed to write super block sector"); + return 1; + } + checksum = exfat_vbr_start_checksum(&sb, sizeof(struct exfat_super_block)); + + memset(sector, 0, get_sector_size()); + sector[get_sector_size() / sizeof(sector[0]) - 1] = + cpu_to_le32(0xaa550000); + for (i = 0; i < 8; i++) + { + if (exfat_write(dev, sector, get_sector_size()) < 0) + { + free(sector); + exfat_error("failed to write a sector with boot signature"); + return 1; + } + checksum = exfat_vbr_add_checksum(sector, get_sector_size(), checksum); + } + + memset(sector, 0, get_sector_size()); + for (i = 0; i < 2; i++) + { + if (exfat_write(dev, sector, get_sector_size()) < 0) + { + free(sector); + exfat_error("failed to write an empty sector"); + return 1; + } + checksum = exfat_vbr_add_checksum(sector, get_sector_size(), checksum); + } + + for (i = 0; i < get_sector_size() / sizeof(sector[0]); i++) + sector[i] = cpu_to_le32(checksum); + if (exfat_write(dev, sector, get_sector_size()) < 0) + { + free(sector); + exfat_error("failed to write checksum sector"); + return 1; + } + + free(sector); + return 0; +} + +const struct fs_object vbr = +{ + .get_alignment = vbr_alignment, + .get_size = vbr_size, + .write = vbr_write, +}; |