--- /dev/null
+/* vi: set sw=4 ts=4: */
+/*
+ * mkfs_vfat: utility to create FAT32 filesystem
+ * inspired by dosfstools
+ *
+ * Busybox'ed (2009) by Vladimir Dronnikov <dronnikov@gmail.com>
+ *
+ * Licensed under GPLv2, see file LICENSE in this tarball for details.
+ */
+#include "libbb.h"
+#include "volume_id/volume_id_internal.h"
+
+#include <linux/hdreg.h> /* HDIO_GETGEO */
+#include <linux/fd.h> /* FDGETPRM */
+//#include <linux/msdos_fs.h>
+
+#define SECTOR_SIZE 512
+
+#define SECTORS_PER_BLOCK (BLOCK_SIZE / SECTOR_SIZE)
+
+// M$ says the high 4 bits of a FAT32 FAT entry are reserved
+#define EOF_FAT32 0x0FFFFFF8
+#define BAD_FAT32 0x0FFFFFF7
+#define MAX_CLUST_32 0x0FFFFFF0
+
+#define ATTR_VOLUME 8
+
+#define NUM_FATS 2
+
+/* FAT32 filesystem looks like this:
+ * sector -nn...-1: "hidden" sectors, all sectors before this partition
+ * (-h hidden-sectors sets it. Useful only for boot loaders,
+ * they need to know _disk_ offset in order to be able to correctly
+ * address sectors relative to start of disk)
+ * sector 0: boot sector
+ * sector 1: info sector
+ * sector 2: set aside for boot code which didn't fit into sector 0
+ * ...(zero-filled sectors)...
+ * sector B: backup copy of sector 0 [B set by -b backup-boot-sector]
+ * sector B+1: backup copy of sector 1
+ * sector B+2: backup copy of sector 2
+ * ...(zero-filled sectors)...
+ * sector R: FAT#1 [R set by -R reserved-sectors]
+ * ...(FAT#1)...
+ * sector R+fat_size: FAT#2
+ * ...(FAT#2)...
+ * sector R+fat_size*2: cluster #2
+ * ...(cluster #2)...
+ * sector R+fat_size*2+clust_size: cluster #3
+ * ...(the rest is filled by clusters till the end)...
+ */
+
+enum {
+// Perhaps this should remain constant
+ info_sector_number = 1,
+// TODO: make these cmdline options
+// dont forget sanity check: backup_boot_sector + 3 <= reserved_sect
+ backup_boot_sector = 3,
+ reserved_sect = 6,
+};
+
+// how many blocks we try to read while testing
+#define TEST_BUFFER_BLOCKS 16
+
+struct msdos_dir_entry {
+ char name[11]; /* 000 name and extension */
+ uint8_t attr; /* 00b attribute bits */
+ uint8_t lcase; /* 00c case for base and extension */
+ uint8_t ctime_cs; /* 00d creation time, centiseconds (0-199) */
+ uint16_t ctime; /* 00e creation time */
+ uint16_t cdate; /* 010 creation date */
+ uint16_t adate; /* 012 last access date */
+ uint16_t starthi; /* 014 high 16 bits of cluster in FAT32 */
+ uint16_t time; /* 016 time */
+ uint16_t date; /* 018 date */
+ uint16_t start; /* 01a first cluster */
+ uint32_t size; /* 01c file size in bytes */
+} __attribute__ ((packed));
+
+/* Example of boot sector's beginning:
+0000 eb 58 90 4d 53 57 49 4e 34 2e 31 00 02 08 26 00 |...MSWIN4.1...&.|
+0010 02 00 00 00 00 f8 00 00 3f 00 ff 00 3f 00 00 00 |........?...?...|
+0020 54 9b d0 00 0d 34 00 00 00 00 00 00 02 00 00 00 |T....4..........|
+0030 01 00 06 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
+0040 80 00 29 71 df 51 e0 4e 4f 20 4e 41 4d 45 20 20 |..)q.Q.NO NAME |
+0050 20 20 46 41 54 33 32 20 20 20 33 c9 8e d1 bc f4 | FAT32 3.....|
+*/
+struct msdos_volume_info { /* (offsets are relative to start of boot sector) */
+ uint8_t drive_number; /* 040 BIOS drive number */
+ uint8_t reserved; /* 041 unused */
+ uint8_t ext_boot_sign; /* 042 0x29 if fields below exist (DOS 3.3+) */
+ uint32_t volume_id32; /* 043 volume ID number */
+ char volume_label[11];/* 047 volume label */
+ char fs_type[8]; /* 052 typically "FATnn" */
+} __attribute__ ((packed)); /* 05a end. Total size 26 (0x1a) bytes */
+
+struct msdos_boot_sector {
+ char boot_jump[3]; /* 000 short or near jump instruction */
+ char system_id[8]; /* 003 name - can be used to special case partition manager volumes */
+ uint16_t bytes_per_sect; /* 00b bytes per logical sector */
+ uint8_t sect_per_clust; /* 00d sectors/cluster */
+ uint16_t reserved_sect; /* 00e reserved sectors (sector offset of 1st FAT relative to volume start) */
+ uint8_t fats; /* 010 number of FATs */
+ uint16_t dir_entries; /* 011 root directory entries */
+ uint16_t volume_size_sect; /* 013 volume size in sectors */
+ uint8_t media_byte; /* 015 media code */
+ uint16_t sect_per_fat; /* 016 sectors/FAT */
+ uint16_t sect_per_track; /* 018 sectors per track */
+ uint16_t heads; /* 01a number of heads */
+ uint32_t hidden; /* 01c hidden sectors (sector offset of volume within physical disk) */
+ uint32_t fat32_volume_size_sect; /* 020 volume size in sectors (if volume_size_sect == 0) */
+ uint32_t fat32_sect_per_fat; /* 024 sectors/FAT */
+ uint16_t fat32_flags; /* 028 bit 8: fat mirroring, low 4: active fat */
+ uint8_t fat32_version[2]; /* 02a major, minor filesystem version (I see 0,0) */
+ uint32_t fat32_root_cluster; /* 02c first cluster in root directory */
+ uint16_t fat32_info_sector; /* 030 filesystem info sector (usually 1) */
+ uint16_t fat32_backup_boot; /* 032 backup boot sector (usually 6) */
+ uint32_t reserved2[3]; /* 034 unused */
+ struct msdos_volume_info vi; /* 040 */
+ char boot_code[0x200 - 0x5a - 2]; /* 05a */
+#define BOOT_SIGN 0xAA55
+ uint16_t boot_sign; /* 1fe */
+} __attribute__ ((packed));
+
+#define FAT_FSINFO_SIG1 0x41615252
+#define FAT_FSINFO_SIG2 0x61417272
+struct fat32_fsinfo {
+ uint32_t signature1; /* 0x52,0x52,0x41,0x61, "RRaA" */
+ uint32_t reserved1[128 - 8];
+ uint32_t signature2; /* 0x72,0x72,0x61,0x41, "rrAa" */
+ uint32_t free_clusters; /* free cluster count. -1 if unknown */
+ uint32_t next_cluster; /* most recently allocated cluster */
+ uint32_t reserved2[3];
+ uint16_t reserved3; /* 1fc */
+ uint16_t boot_sign; /* 1fe */
+} __attribute__ ((packed));
+
+struct bug_check {
+ char BUG1[sizeof(struct msdos_dir_entry ) == 0x20 ? 1 : -1];
+ char BUG2[sizeof(struct msdos_volume_info) == 0x1a ? 1 : -1];
+ char BUG3[sizeof(struct msdos_boot_sector) == 0x200 ? 1 : -1];
+ char BUG4[sizeof(struct fat32_fsinfo ) == 0x200 ? 1 : -1];
+};
+
+static const char boot_code[] ALIGN1 =
+ "\x0e" /* 05a: push cs */
+ "\x1f" /* 05b: pop ds */
+ "\xbe\x77\x7c" /* write_msg: mov si, offset message_txt */
+ "\xac" /* 05f: lodsb */
+ "\x22\xc0" /* 060: and al, al */
+ "\x74\x0b" /* 062: jz key_press */
+ "\x56" /* 064: push si */
+ "\xb4\x0e" /* 065: mov ah, 0eh */
+ "\xbb\x07\x00" /* 067: mov bx, 0007h */
+ "\xcd\x10" /* 06a: int 10h */
+ "\x5e" /* 06c: pop si */
+ "\xeb\xf0" /* 06d: jmp write_msg */
+ "\x32\xe4" /* key_press: xor ah, ah */
+ "\xcd\x16" /* 071: int 16h */
+ "\xcd\x19" /* 073: int 19h */
+ "\xeb\xfe" /* foo: jmp foo */
+ /* 077: message_txt: */
+ "This is not a bootable disk\r\n";
+
+
+// mark specified cluster as having a particular value
+#define mark_cluster(cluster, value) \
+ ((uint32_t *)fat)[cluster] = cpu_to_le32(value)
+
+void BUG_unsupported_field_size(void);
+#define STORE_LE(field, value) \
+do { \
+ if (sizeof(field) == 4) \
+ field = cpu_to_le32(value); \
+ else if (sizeof(field) == 2) \
+ field = cpu_to_le16(value); \
+ else if (sizeof(field) == 1) \
+ field = (value); \
+ else \
+ BUG_unsupported_field_size(); \
+} while (0)
+
+/* compat:
+ * mkdosfs 2.11 (12 Mar 2005)
+ * Usage: mkdosfs [-A] [-c] [-C] [-v] [-I] [-l bad-block-file]
+ * [-b backup-boot-sector]
+ * [-m boot-msg-file] [-n volume-name] [-i volume-id]
+ * [-s sectors-per-cluster] [-S logical-sector-size]
+ * [-f number-of-FATs]
+ * [-h hidden-sectors] [-F fat-size] [-r root-dir-entries]
+ * [-R reserved-sectors]
+ * /dev/name [blocks]
+ */
+int mkfs_vfat_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int mkfs_vfat_main(int argc UNUSED_PARAM, char **argv)
+{
+ struct stat st;
+ const char *volume_label = "";
+ char *buf;
+ char *device_name;
+ uoff_t volume_size_bytes;
+ uoff_t volume_size_blocks;
+ uoff_t volume_size_sect;
+ uint32_t total_clust;
+ uint32_t volume_id;
+ int dev;
+ unsigned bytes_per_sect;
+ unsigned sect_per_fat;
+ unsigned opts;
+ uint16_t sect_per_track;
+ uint8_t media_byte;
+ uint8_t sect_per_clust;
+ uint8_t heads;
+ enum {
+ OPT_A = 1 << 0, // [IGNORED] atari format
+ OPT_b = 1 << 1, // [IGNORED] location of backup boot sector
+ OPT_c = 1 << 2, // [IGNORED] check filesystem
+ OPT_C = 1 << 3, // [IGNORED] create a new file
+ OPT_f = 1 << 4, // [IGNORED] number of FATs
+ OPT_F = 1 << 5, // [IGNORED, implied 32] choose FAT size
+ OPT_h = 1 << 6, // [IGNORED] number of hidden sectors
+ OPT_I = 1 << 7, // [IGNORED] don't bark at entire disk devices
+ OPT_i = 1 << 8, // [IGNORED] volume ID
+ OPT_l = 1 << 9, // [IGNORED] bad block filename
+ OPT_m = 1 << 10, // [IGNORED] message file
+ OPT_n = 1 << 11, // volume label
+ OPT_r = 1 << 12, // [IGNORED] root directory entries
+ OPT_R = 1 << 13, // [IGNORED] number of reserved sectors
+ OPT_s = 1 << 14, // [IGNORED] sectors per cluster
+ OPT_S = 1 << 15, // [IGNORED] sector size
+ OPT_v = 1 << 16, // verbose
+ };
+
+ opt_complementary = "-1";//:b+:f+:F+:h+:r+:R+:s+:S+:vv:c--l:l--c";
+ opts = getopt32(argv, "Ab:cCf:F:h:Ii:l:m:n:r:R:s:S:v",
+ NULL, NULL, NULL, NULL, NULL,
+ NULL, NULL, &volume_label, NULL, NULL, NULL, NULL);
+ argv += optind;
+
+ // cache device name
+ device_name = argv[0];
+ // default volume ID = creation time
+ volume_id = time(NULL);
+
+ dev = xopen(device_name, O_EXCL | O_RDWR);
+ if (fstat(dev, &st) < 0)
+ bb_simple_perror_msg_and_die(device_name);
+
+ //
+ // Get image size and sector size
+ //
+ bytes_per_sect = SECTOR_SIZE;
+ volume_size_bytes = st.st_size;
+ if (!S_ISBLK(st.st_mode)) {
+ if (!S_ISREG(st.st_mode)) {
+ if (!argv[1])
+ bb_error_msg_and_die("image size must be specified");
+ }
+ // not a block device, skip bad sectors check
+ opts &= ~OPT_c;
+ } else {
+ int min_bytes_per_sect;
+
+ // more portable than BLKGETSIZE[64]
+ volume_size_bytes = xlseek(dev, 0, SEEK_END);
+ xlseek(dev, 0, SEEK_SET);
+#if 0
+ unsigned device_num;
+ // for true block devices we do check sanity
+ device_num = st.st_rdev & 0xff3f;
+ // do we allow to format the whole disk device?
+ if (!(opts & OPT_I) && (
+ device_num == 0x0300 || // hda, hdb
+ (device_num & 0xff0f) == 0x0800 || // sd
+ device_num == 0x0d00 || // xd
+ device_num == 0x1600 ) // hdc, hdd
+ )
+ bb_error_msg_and_die("Will not try to make filesystem on full-disk device (use -I if wanted)");
+ // can't work on mounted filesystems
+ if (find_mount_point(device_name, NULL))
+ bb_error_msg_and_die("Can't format mounted filesystem");
+#endif
+ // get true sector size
+ // (parameter must be int*, not long* or size_t*)
+ xioctl(dev, BLKSSZGET, &min_bytes_per_sect);
+ if (min_bytes_per_sect > SECTOR_SIZE) {
+ bytes_per_sect = min_bytes_per_sect;
+ bb_error_msg("for this device sector size is %u", min_bytes_per_sect);
+ }
+ }
+ if (argv[1]) {
+ volume_size_bytes = XATOOFF(argv[1]);
+ if (volume_size_bytes >= MAXINT(off_t) / 1024)
+ bb_error_msg_and_die("image size is too big");
+ volume_size_bytes *= 1024;
+ }
+ volume_size_blocks = (volume_size_bytes >> BLOCK_SIZE_BITS);
+ volume_size_sect = volume_size_bytes / bytes_per_sect;
+
+ //
+ // Find out or guess media parameters
+ //
+ media_byte = 0xf8;
+ heads = 255;
+ sect_per_track = 63;
+ sect_per_clust = 1;
+ {
+ struct hd_geometry geometry;
+ // size (in sectors), sect (per track), head
+ struct floppy_struct param;
+
+ // N.B. whether to use HDIO_GETGEO or HDIO_REQ?
+ if (ioctl(dev, HDIO_GETGEO, &geometry) == 0
+ && geometry.sectors
+ && geometry.heads
+ ) {
+ // hard drive
+ sect_per_track = geometry.sectors;
+ heads = geometry.heads;
+
+ set_cluster_size:
+ /* For FAT32, try to do the same as M$'s format command
+ * (see http://www.win.tue.nl/~aeb/linux/fs/fat/fatgen103.pdf p. 20):
+ * fs size <= 260M: 0.5k clusters
+ * fs size <= 8G: 4k clusters
+ * fs size <= 16G: 8k clusters
+ * fs size > 16G: 16k clusters
+ */
+ sect_per_clust = volume_size_bytes > ((off_t)16)*1024*1024*1024 ? 32 :
+ volume_size_bytes > ((off_t)8)*1024*1024*1024 ? 16 :
+ volume_size_bytes > 260*1024*1024 ? 8 : 1;
+ } else {
+ int not_floppy = ioctl(dev, FDGETPRM, ¶m);
+ if (not_floppy == 0) {
+ // floppy disk
+ sect_per_track = param.sect;
+ heads = param.head;
+ volume_size_sect = param.size;
+ volume_size_bytes = param.size * SECTOR_SIZE;
+ }
+ // setup the media descriptor byte
+ switch (volume_size_sect) {
+ case 2*360: // 5.25", 2, 9, 40 - 360K
+ media_byte = 0xfd;
+ break;
+ case 2*720: // 3.5", 2, 9, 80 - 720K
+ case 2*1200: // 5.25", 2, 15, 80 - 1200K
+ media_byte = 0xf9;
+ break;
+ default: // anything else
+ if (not_floppy)
+ goto set_cluster_size;
+ case 2*1440: // 3.5", 2, 18, 80 - 1440K
+ case 2*2880: // 3.5", 2, 36, 80 - 2880K
+ media_byte = 0xf0;
+ break;
+ }
+ // not floppy, but size matches floppy exactly.
+ // perhaps it is a floppy image.
+ // we already set media_byte as if it is a floppy,
+ // now set sect_per_track and heads.
+ heads = 2;
+ sect_per_track = (unsigned)volume_size_sect / 160;
+ if (sect_per_track < 9)
+ sect_per_track = 9;
+ }
+ }
+
+ //
+ // Calculate number of clusters, sectors/cluster, sectors/FAT
+ // (an initial guess for sect_per_clust should already be set)
+ //
+ if ((off_t)(volume_size_sect - reserved_sect) < 16) // arbitrary limit
+ bb_error_msg_and_die("the image is too small for FAT32");
+ sect_per_fat = 1;
+ while (1) {
+ while (1) {
+ unsigned spf;
+ off_t tcl = (volume_size_sect - reserved_sect - NUM_FATS * sect_per_fat) / sect_per_clust;
+ // tcl may be > MAX_CLUST_32 here, but it may be
+ // because sect_per_fat is underestimated,
+ // and with increased sect_per_fat it still may become
+ // <= MAX_CLUST_32. Therefore, we do not check
+ // against MAX_CLUST_32, but against a bigger const:
+ if (tcl > 0x7fffffff)
+ goto next;
+ total_clust = tcl; // fits in uint32_t
+ spf = ((total_clust + 2) * 4 + bytes_per_sect - 1) / bytes_per_sect;
+ if (spf <= sect_per_fat) {
+ // do not need to adjust sect_per_fat.
+ // so, was total_clust too big after all?
+ if (total_clust <= MAX_CLUST_32)
+ goto found_total_clust; // no
+ // yes, total_clust is _a bit_ too big
+ goto next;
+ }
+ // adjust sect_per_fat, go back and recalc total_clust
+ sect_per_fat = spf;
+ }
+ next:
+ if (sect_per_clust == 128)
+ bb_error_msg_and_die("can't make FAT32 with >128 sectors/cluster");
+ sect_per_clust *= 2;
+ sect_per_fat = (sect_per_fat / 2) | 1;
+ }
+ found_total_clust:
+
+ //
+ // Print info
+ //
+ if (opts & OPT_v) {
+ fprintf(stderr,
+ "Device '%s':\n"
+ "heads:%u, sectors/track:%u, bytes/sector:%u\n"
+ "media descriptor:0x%02x\n"
+ "total sectors:%"OFF_FMT"u, clusters:%u, sectors/cluster:%u\n"
+ "FATs:2, sectors/FAT:%u\n"
+ "volumeID:%08x, label:'%s'\n",
+ device_name,
+ heads, sect_per_track, bytes_per_sect,
+ (int)media_byte,
+ volume_size_sect, (int)total_clust, (int)sect_per_clust,
+ sect_per_fat,
+ (int)volume_id, volume_label
+ );
+ }
+
+ //
+ // Write filesystem image sequentially (no seeking)
+ //
+ {
+ unsigned bufsize = reserved_sect;
+ //bufsize |= sect_per_fat; // can be quite large
+ bufsize |= 2; // use this instead
+ bufsize |= sect_per_clust;
+ buf = xzalloc(bufsize * bytes_per_sect);
+ }
+
+ { // boot, fsinfo sectors and their copies
+ struct msdos_boot_sector *boot_blk = (void*)buf;
+ struct fat32_fsinfo *info = (void*)(buf + bytes_per_sect);
+
+ strcpy(boot_blk->boot_jump, "\xeb\x58\x90" "mkdosfs"); // system_id[8] included :)
+ STORE_LE(boot_blk->bytes_per_sect, bytes_per_sect);
+ STORE_LE(boot_blk->sect_per_clust, sect_per_clust);
+ STORE_LE(boot_blk->reserved_sect, reserved_sect);
+ STORE_LE(boot_blk->fats, 2);
+ //STORE_LE(boot_blk->dir_entries, 0); // for FAT32, stays 0
+ if (volume_size_sect <= 0xffff)
+ STORE_LE(boot_blk->volume_size_sect, volume_size_sect);
+ STORE_LE(boot_blk->media_byte, media_byte);
+ // Bad: this would make Linux to think that it's fat12/16
+ //if (sect_per_fat <= 0xffff)
+ // STORE_LE(boot_blk->sect_per_fat, sect_per_fat);
+ //STORE_LE(boot_blk->sect_per_fat, 0);
+ STORE_LE(boot_blk->sect_per_track, sect_per_track);
+ STORE_LE(boot_blk->heads, heads);
+ //STORE_LE(boot_blk->hidden, 0);
+ STORE_LE(boot_blk->fat32_volume_size_sect, volume_size_sect);
+ STORE_LE(boot_blk->fat32_sect_per_fat, sect_per_fat);
+ //STORE_LE(boot_blk->fat32_flags, 0);
+ //STORE_LE(boot_blk->fat32_version[2], 0,0);
+ STORE_LE(boot_blk->fat32_root_cluster, 2);
+ STORE_LE(boot_blk->fat32_info_sector, info_sector_number);
+ STORE_LE(boot_blk->fat32_backup_boot, backup_boot_sector);
+ //STORE_LE(boot_blk->reserved2[3], 0,0,0);
+ STORE_LE(boot_blk->vi.ext_boot_sign, 0x29);
+ STORE_LE(boot_blk->vi.volume_id32, volume_id);
+ strncpy(boot_blk->vi.fs_type, "FAT32 ", sizeof(boot_blk->vi.fs_type));
+ strncpy(boot_blk->vi.volume_label, volume_label, sizeof(boot_blk->vi.volume_label));
+ memcpy(boot_blk->boot_code, boot_code, sizeof(boot_code));
+ STORE_LE(boot_blk->boot_sign, BOOT_SIGN);
+
+ STORE_LE(info->signature1, FAT_FSINFO_SIG1);
+ STORE_LE(info->signature2, FAT_FSINFO_SIG2);
+ // we've allocated cluster 2 for the root dir
+ STORE_LE(info->free_clusters, (total_clust - 1));
+ STORE_LE(info->next_cluster, 2);
+ STORE_LE(info->boot_sign, BOOT_SIGN);
+
+ // 1st copy
+ xwrite(dev, buf, bytes_per_sect * backup_boot_sector);
+ // 2nd copy and possibly zero sectors
+ xwrite(dev, buf, bytes_per_sect * (reserved_sect - backup_boot_sector));
+ }
+
+ { // file allocation tables
+ unsigned i,j;
+ unsigned char *fat = (void*)buf;
+
+ memset(buf, 0, bytes_per_sect * 2);
+ // initial FAT entries
+ mark_cluster(0, 0x0fffff00 | media_byte);
+ mark_cluster(1, 0xffffffff);
+ // mark cluster 2 as EOF (used for root dir)
+ mark_cluster(2, EOF_FAT32);
+ for (i = 0; i < NUM_FATS; i++) {
+ xwrite(dev, buf, bytes_per_sect);
+ for (j = 1; j < sect_per_fat; j++)
+ xwrite(dev, buf + bytes_per_sect, bytes_per_sect);
+ }
+ }
+
+ // root directory
+ // empty directory is just a set of zero bytes
+ memset(buf, 0, sect_per_clust * bytes_per_sect);
+ if (volume_label[0]) {
+ // create dir entry for volume_label
+ struct msdos_dir_entry *de;
+#if 0
+ struct tm tm;
+ uint16_t t, d;
+#endif
+ de = (void*)buf;
+ strncpy(de->name, volume_label, sizeof(de->name));
+ STORE_LE(de->attr, ATTR_VOLUME);
+#if 0
+ localtime_r(&create_time, &tm);
+ t = (tm.tm_sec >> 1) + (tm.tm_min << 5) + (tm.tm_hour << 11);
+ d = tm.tm_mday + ((tm.tm_mon+1) << 5) + ((tm.tm_year-80) << 9);
+ STORE_LE(de->time, t);
+ STORE_LE(de->date, d);
+ //STORE_LE(de->ctime_cs, 0);
+ de->ctime = de->time;
+ de->cdate = de->date;
+ de->adate = de->date;
+#endif
+ }
+ xwrite(dev, buf, sect_per_clust * bytes_per_sect);
+
+#if 0
+ if (opts & OPT_c) {
+ unsigned start_data_sector;
+ unsigned start_data_block;
+ unsigned badblocks = 0;
+ int try, got;
+ off_t currently_testing;
+ char *blkbuf = xmalloc(BLOCK_SIZE * TEST_BUFFER_BLOCKS);
+
+ // N.B. the two following vars are in hard sectors, i.e. SECTOR_SIZE byte sectors!
+ start_data_sector = (reserved_sect + NUM_FATS * sect_per_fat) * (bytes_per_sect / SECTOR_SIZE);
+ start_data_block = (start_data_sector + SECTORS_PER_BLOCK - 1) / SECTORS_PER_BLOCK;
+
+ bb_info_msg("Searching for bad blocks ");
+ currently_testing = 0;
+ try = TEST_BUFFER_BLOCKS;
+ while (currently_testing < volume_size_blocks) {
+ if (currently_testing + try > volume_size_blocks)
+ try = volume_size_blocks - currently_testing;
+ // perform a test on a block. return the number of blocks
+ // that could be read successfully.
+ // seek to the correct location
+ xlseek(dev, currently_testing * BLOCK_SIZE, SEEK_SET);
+ // try reading
+ got = read(dev, blkbuf, try * BLOCK_SIZE);
+ if (got < 0)
+ got = 0;
+ if (got & (BLOCK_SIZE - 1))
+ bb_error_msg("Unexpected values in do_check: probably bugs");
+ got /= BLOCK_SIZE;
+ currently_testing += got;
+ if (got == try) {
+ try = TEST_BUFFER_BLOCKS;
+ continue;
+ }
+ try = 1;
+ if (currently_testing < start_data_block)
+ bb_error_msg_and_die("bad blocks before data-area: cannot make fs");
+
+ // mark all of the sectors in the block as bad
+ for (i = 0; i < SECTORS_PER_BLOCK; i++) {
+ int cluster = (currently_testing * SECTORS_PER_BLOCK + i - start_data_sector) / (int) (sect_per_clust) / (bytes_per_sect / SECTOR_SIZE);
+ if (cluster < 0)
+ bb_error_msg_and_die("Invalid cluster number in mark_sector: probably bug!");
+ mark_cluster(cluster, BAD_FAT32);
+ }
+ badblocks++;
+ currently_testing++;
+ }
+ free(blkbuf);
+ if (badblocks)
+ bb_info_msg("%d bad block(s)", badblocks);
+ }
+#endif
+
+ // cleanup
+ if (ENABLE_FEATURE_CLEAN_UP) {
+ free(buf);
+ close(dev);
+ }
+
+ return 0;
+}
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