/* 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 source tree. */ //config:config MKDOSFS //config: bool "mkdosfs (6.8 kb)" //config: default y //config: select PLATFORM_LINUX //config: help //config: Utility to create FAT32 filesystems. //config: //config:config MKFS_VFAT //config: bool "mkfs.vfat (6.8 kb)" //config: default y //config: select PLATFORM_LINUX //config: help //config: Alias to "mkdosfs". // APPLET_ODDNAME:name main location suid_type help //applet:IF_MKDOSFS( APPLET_ODDNAME(mkdosfs, mkfs_vfat, BB_DIR_SBIN, BB_SUID_DROP, mkfs_vfat)) //applet:IF_MKFS_VFAT(APPLET_ODDNAME(mkfs.vfat, mkfs_vfat, BB_DIR_SBIN, BB_SUID_DROP, mkfs_vfat)) //kbuild:lib-$(CONFIG_MKDOSFS) += mkfs_vfat.o //kbuild:lib-$(CONFIG_MKFS_VFAT) += mkfs_vfat.o //usage:#define mkfs_vfat_trivial_usage //usage: "[-v] [-n LABEL] BLOCKDEV [KBYTES]" /* Accepted but ignored: "[-c] [-C] [-I] [-l bad-block-file] [-b backup-boot-sector] " "[-m boot-msg-file] [-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] " */ //usage:#define mkfs_vfat_full_usage "\n\n" //usage: "Make a FAT32 filesystem\n" /* //usage: "\n -c Check device for bad blocks" */ //usage: "\n -v Verbose" /* //usage: "\n -I Allow to use entire disk device (e.g. /dev/hda)" */ //usage: "\n -n LBL Volume label" #include "libbb.h" #include <linux/hdreg.h> /* HDIO_GETGEO */ #include <linux/fd.h> /* FDGETPRM */ #include <sys/mount.h> /* BLKSSZGET */ #if !defined(BLKSSZGET) # define BLKSSZGET _IO(0x12, 104) #endif //#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 */ } 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" */ } PACKED; /* 05a end. Total size 26 (0x1a) bytes */ struct msdos_boot_sector { /* We use strcpy to fill both, and gcc-4.4.x complains if they are separate */ char boot_jump_and_sys_id[3+8]; /* 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 */ } 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 */ } 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"; #define MARK_CLUSTER(cluster, value) \ ((uint32_t *)fat)[cluster] = SWAP_LE32(value) void BUG_unsupported_field_size(void); #define STORE_LE(field, value) \ do { \ if (sizeof(field) == 4) \ field = SWAP_LE32(value); \ else if (sizeof(field) == 2) \ field = SWAP_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_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 }; opts = getopt32(argv, "^" "Ab:cCf:F:h:Ii:l:m:n:r:R:s:S:v" "\0" "-1", //:b+:f+:F+:h+:r+:R+:s+:S+:vv:c--l:l--c 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_RDWR); xfstat(dev, &st, device_name); // // Get image size and sector size // bytes_per_sect = SECTOR_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; #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, 0)) 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); } } volume_size_bytes = get_volume_size_in_bytes(dev, argv[1], 1024, /*extend:*/ 1); 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 = 1; if (volume_size_bytes >= 260*1024*1024) { sect_per_clust = 8; /* fight gcc: */ /* "error: integer overflow in expression" */ /* "error: right shift count >= width of type" */ if (sizeof(off_t) > 4) { unsigned t = (volume_size_bytes >> 31 >> 1); if (t >= 8/4) sect_per_clust = 16; if (t >= 16/4) sect_per_clust = 32; } } } else { // floppy, loop, or regular file 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) // // "mkdosfs -v -F 32 image5k 5" is the minimum: // 2 sectors for FATs and 2 data sectors if ((off_t)(volume_size_sect - reserved_sect) < 4) bb_error_msg_and_die("the image is too small for FAT32"); sect_per_fat = 1; while (1) { while (1) { int spf_adj; uoff_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 > 0x80ffffff) goto next; total_clust = tcl; // fits in uint32_t // Every cluster needs 4 bytes in FAT. +2 entries since // FAT has space for non-existent clusters 0 and 1. // Let's see how many sectors that needs. //May overflow at "*4": //spf_adj = ((total_clust+2) * 4 + bytes_per_sect-1) / bytes_per_sect - sect_per_fat; //Same in the more obscure, non-overflowing form: spf_adj = ((total_clust+2) + (bytes_per_sect/4)-1) / (bytes_per_sect/4) - sect_per_fat; #if 0 bb_error_msg("sect_per_clust:%u sect_per_fat:%u total_clust:%u", sect_per_clust, sect_per_fat, (int)tcl); bb_error_msg("adjust to sect_per_fat:%d", spf_adj); #endif if (spf_adj <= 0) { // 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 // (note: just "sect_per_fat += spf_adj" isn't ok) sect_per_fat += ((unsigned)spf_adj / 2) | 1; } 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:%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) // { // (a | b) is poor man's max(a, b) 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 and 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_and_sys_id, "\xeb\x58\x90" "mkdosfs"); STORE_LE(boot_blk->bytes_per_sect, bytes_per_sect); STORE_LE(boot_blk->sect_per_clust, sect_per_clust); // cast in needed on big endian to suppress a warning STORE_LE(boot_blk->reserved_sect, (uint16_t)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); // wrong: this would make Linux think that it's fat12/16: //if (sect_per_fat <= 0xffff) // STORE_LE(boot_blk->sect_per_fat, sect_per_fat); // works: //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_time; 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_time); t = (tm_time.tm_sec >> 1) + (tm_time.tm_min << 5) + (tm_time.tm_hour << 11); d = tm_time.tm_mday + ((tm_time.tm_mon+1) << 5) + ((tm_time.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) { uoff_t volume_size_blocks; 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); volume_size_blocks = (volume_size_bytes >> BLOCK_SIZE_BITS); // 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_error_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_error_msg("%d bad block(s)", badblocks); } #endif // cleanup if (ENABLE_FEATURE_CLEAN_UP) { free(buf); close(dev); } return 0; }