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  /*
   * mkfs_reiser: utility to create ReiserFS filesystem
   *
   * Busybox'ed (2009) by Vladimir Dronnikov <dronnikov@gmail.com>
   *
   * Licensed under GPLv2, see file LICENSE in this source tree.
   */
  //config:config MKFS_REISER
  //config:	bool "mkfs_reiser"
  //config:	default n
  //config:	help
  //config:	Utility to create ReiserFS filesystems.
  //config:	Note: this applet needs a lot of testing and polishing.
  
  //applet:IF_MKFS_REISER(APPLET_ODDNAME(mkfs.reiser, mkfs_reiser, BB_DIR_SBIN, BB_SUID_DROP, mkfs_reiser))
  
  //kbuild:lib-$(CONFIG_MKFS_REISER) += mkfs_reiser.o
  
  //usage:#define mkfs_reiser_trivial_usage
  //usage:       "[-f] [-l LABEL] BLOCKDEV [4K-BLOCKS]"
  //usage:#define mkfs_reiser_full_usage "\n\n"
  //usage:       "Make a ReiserFS V3 filesystem\n"
  //usage:     "\n	-f	Force"
  //usage:     "\n	-l LBL	Volume label"
  
  #include "libbb.h"
  #include <linux/fs.h>
  
  struct journal_params {
  	uint32_t jp_journal_1st_block;      /* where does journal start from on its device */
  	uint32_t jp_journal_dev;            /* journal device st_rdev */
  	uint32_t jp_journal_size;           /* size of the journal on FS creation. used to make sure they don't overflow it */
  	uint32_t jp_journal_trans_max;      /* max number of blocks in a transaction.  */
  	uint32_t jp_journal_magic;          /* random value made on fs creation (this was sb_journal_block_count) */
  	uint32_t jp_journal_max_batch;      /* max number of blocks to batch into a trans */
  	uint32_t jp_journal_max_commit_age; /* in seconds, how old can an async commit be */
  	uint32_t jp_journal_max_trans_age;  /* in seconds, how old can a transaction be */
  };
  
  struct reiserfs_journal_header {
  	uint32_t jh_last_flush_trans_id;    /* id of last fully flushed transaction */
  	uint32_t jh_first_unflushed_offset; /* offset in the log of where to start replay after a crash */
  	uint32_t jh_mount_id;
  	struct journal_params jh_journal;
  	uint32_t jh_last_check_mount_id;    /* the mount id of the fs during the last reiserfsck --check. */
  };
  
  struct reiserfs_super_block {
  	uint32_t sb_block_count;            /* 0 number of block on data device */
  	uint32_t sb_free_blocks;            /* 4 free blocks count */
  	uint32_t sb_root_block;             /* 8 root of the tree */
  
  	struct journal_params sb_journal;   /* 12 */
  
  	uint16_t sb_blocksize;          /* 44 */
  	uint16_t sb_oid_maxsize;        /* 46 max size of object id array, see get_objectid() commentary */
  	uint16_t sb_oid_cursize;        /* 48 current size of object id array */
  	uint16_t sb_umount_state;       /* 50 this is set to 1 when filesystem was umounted, to 2 - when not */
  
  	char s_magic[10];               /* 52 "ReIsErFs" or "ReIsEr2Fs" or "ReIsEr3Fs" */
  	uint16_t sb_fs_state;           /* 62 it is set to used by fsck to mark which phase of rebuilding is done (used for fsck debugging) */
  	uint32_t sb_hash_function_code; /* 64 code of function which was/is/will be used to sort names in a directory. See codes in above */
  	uint16_t sb_tree_height;        /* 68 height of filesytem tree. Tree consisting of only one root block has 2 here */
  	uint16_t sb_bmap_nr;            /* 70 amount of bitmap blocks needed to address each block of file system */
  	uint16_t sb_version;            /* 72 this field is only reliable on filesystem with non-standard journal */
  	uint16_t sb_reserved_for_journal;  /* 74 size in blocks of journal area on main device, we need to keep after non-standard journal relocation */
  	uint32_t sb_inode_generation;   /* 76 */
  	uint32_t sb_flags;              /* 80 Right now used only by inode-attributes, if enabled */
  	unsigned char s_uuid[16];       /* 84 filesystem unique identifier */
  	unsigned char s_label[16];      /* 100 filesystem volume label */
  	uint16_t sb_mnt_count;          /* 116 */
  	uint16_t sb_max_mnt_count;      /* 118 */
  	uint32_t sb_lastcheck;          /* 120 */
  	uint32_t sb_check_interval;     /* 124 */
  /* zero filled by mkreiserfs and reiserfs_convert_objectid_map_v1() so any additions must be updated there as well. */
  	char s_unused[76];              /* 128 */
  	/* 204 */
  };
  
  /* Header of a disk block.  More precisely, header of a formatted leaf
     or internal node, and not the header of an unformatted node. */
  struct block_head {
  	uint16_t blk2_level;        /* Level of a block in the tree. */
  	uint16_t blk2_nr_item;      /* Number of keys/items in a block. */
  	uint16_t blk2_free_space;   /* Block free space in bytes. */
  	uint16_t blk_reserved;
  	uint32_t reserved[4];
  };
  
  #define REISERFS_DISK_OFFSET_IN_BYTES (64 * 1024)
  
  #define REISERFS_3_6_SUPER_MAGIC_STRING "ReIsEr2Fs"
  #define REISERFS_FORMAT_3_6     2
  #define DEFAULT_MAX_MNT_COUNT   30                      /* 30 mounts */
  #define DEFAULT_CHECK_INTERVAL  (180 * 60 * 60 * 24)    /* 180 days */
  
  #define FS_CLEANLY_UMOUNTED     1 /* this was REISERFS_VALID_FS */
  
  #define JOURNAL_MIN_SIZE        512
  /* biggest possible single transaction, don't change for now (8/3/99) */
  #define JOURNAL_TRANS_MAX       1024
  #define JOURNAL_TRANS_MIN       256     /* need to check whether it works */
  #define JOURNAL_DEFAULT_RATIO   8       /* default journal size / max trans length */
  #define JOURNAL_MIN_RATIO       2
  /* max blocks to batch into one transaction, don't make this any bigger than 900 */
  #define JOURNAL_MAX_BATCH       900
  #define JOURNAL_MAX_COMMIT_AGE  30
  
  
  // Standard mkreiserfs 3.6.21:
  //   -b | --block-size N              size of file-system block, in bytes
  //   -j | --journal-device FILE       path to separate device to hold journal
  //   -s | --journal-size N            size of the journal in blocks
  //   -o | --journal-offset N          offset of the journal from the start of
  //                                    the separate device, in blocks
  //   -t | --transaction-max-size N    maximal size of transaction, in blocks
  //   -B | --badblocks file            store all bad blocks given in file on the fs
  //   -h | --hash rupasov|tea|r5       hash function to use by default
  //   -u | --uuid UUID                 store UUID in the superblock
  //   -l | --label LABEL               store LABEL in the superblock
  //   --format 3.5|3.6                 old 3.5 format or newer 3.6
  //   -f | --force                     specified once, make mkreiserfs the whole
  //                                    disk, not block device or mounted partition;
  //                                    specified twice, do not ask for confirmation
  //   -q | --quiet                     quiet work without messages, progress and
  //                                    questions. Useful if run in a script. For use
  //                                    by end users only.
  //   -d | --debug                     print debugging information during mkreiser
  //   -V                               print version and exit
  
  // Options not commented below are taken but silently ignored:
  enum {
  	OPT_b = 1 << 0,
  	OPT_j = 1 << 1,
  	OPT_s = 1 << 2,
  	OPT_o = 1 << 3,
  	OPT_t = 1 << 4,
  	OPT_B = 1 << 5,
  	OPT_h = 1 << 6,
  	OPT_u = 1 << 7,
  	OPT_l = 1 << 8,		// label
  	OPT_f = 1 << 9,		// ask no questions
  	OPT_q = 1 << 10,
  	OPT_d = 1 << 11,
  	//OPT_V = 1 << 12,	// -V version. bbox applets don't support that
  };
  
  int mkfs_reiser_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  int mkfs_reiser_main(int argc UNUSED_PARAM, char **argv)
  {
  	unsigned blocksize = 4096;
  	unsigned journal_blocks = 8192;
  	unsigned blocks, bitmap_blocks, i, block;
  	time_t timestamp;
  	const char *label = "";
  	struct stat st;
  	int fd;
  	uint8_t *buf;
  	struct reiserfs_super_block *sb;
  	struct journal_params *jp;
  	struct block_head *root;
  
  	// using global "option_mask32" instead of local "opts":
  	// we are register starved here
  	/*opts =*/ getopt32(argv, "^" "b:+j:s:o:t:B:h:u:l:fqd" "\0" "-1",
  		NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, &label);
  	argv += optind; // argv[0] -- device
  
  	// check the device is a block device
  	fd = xopen(argv[0], O_WRONLY | O_EXCL);
  	xfstat(fd, &st, argv[0]);
  	if (!S_ISBLK(st.st_mode) && !(option_mask32 & OPT_f))
  		bb_error_msg_and_die("%s: not a block device", argv[0]);
  
  	// check if it is mounted
  	// N.B. what if we format a file? find_mount_point will return false negative since
  	// it is loop block device which is mounted!
  	if (find_mount_point(argv[0], 0))
  		bb_simple_error_msg_and_die("can't format mounted filesystem");
  
  	// open the device, get size in blocks
  	blocks = get_volume_size_in_bytes(fd, argv[1], blocksize, /*extend:*/ 1) / blocksize;
  
  	// block number sanity check
  	// we have a limit: skipped area, super block, journal and root block
  	// all have to be addressed by one first bitmap
  	block = REISERFS_DISK_OFFSET_IN_BYTES / blocksize // boot area
  		+ 1		// sb
  		+ 1		// bitmap#0
  		+ journal_blocks+1	// journal
  	;
  
  	// count overhead
  	bitmap_blocks = (blocks - 1) / (blocksize * 8) + 1;
  	i = block + bitmap_blocks;
  
  	// check overhead
  	if (MIN(blocksize * 8, blocks) < i)
  		bb_error_msg_and_die("need >= %u blocks", i);
  
  	// ask confirmation?
  	// TODO: ???
  
  	// wipe out first REISERFS_DISK_OFFSET_IN_BYTES of device
  	// TODO: do we really need to wipe?!
  	xlseek(fd, REISERFS_DISK_OFFSET_IN_BYTES, SEEK_SET);
  
  	// fill superblock
  	sb = (struct reiserfs_super_block *)xzalloc(blocksize);
  	// block count
  	STORE_LE(sb->sb_block_count, blocks);
  	STORE_LE(sb->sb_free_blocks, blocks - i);
  	// TODO: decypher!
  	STORE_LE(sb->sb_root_block, block);
  	// fill journal related fields
  	jp = &sb->sb_journal;
  	STORE_LE(jp->jp_journal_1st_block, REISERFS_DISK_OFFSET_IN_BYTES / blocksize + 1/*sb*/ + 1/*bmp#0*/);
  	timestamp = time(NULL);
  	srand(timestamp);
  	STORE_LE(jp->jp_journal_magic, rand());
  	STORE_LE(jp->jp_journal_size, journal_blocks);
  	STORE_LE(jp->jp_journal_trans_max, JOURNAL_TRANS_MAX);
  	STORE_LE(jp->jp_journal_max_batch, JOURNAL_MAX_BATCH);
  	STORE_LE(jp->jp_journal_max_commit_age, JOURNAL_MAX_COMMIT_AGE);
  	// sizes
  	STORE_LE(sb->sb_blocksize, blocksize);
  	STORE_LE(sb->sb_oid_maxsize, (blocksize - sizeof(*sb)) / sizeof(uint32_t) / 2 * 2);
  	STORE_LE(sb->sb_oid_cursize, 2); // "." and ".."
  	strcpy(sb->s_magic, REISERFS_3_6_SUPER_MAGIC_STRING);
  	STORE_LE(sb->sb_bmap_nr, (bitmap_blocks > ((1LL << 16) - 1)) ? 0 : bitmap_blocks);
  	// misc
  	STORE_LE(sb->sb_version, REISERFS_FORMAT_3_6);
  	STORE_LE(sb->sb_lastcheck, timestamp);
  	STORE_LE(sb->sb_check_interval, DEFAULT_CHECK_INTERVAL);
  	STORE_LE(sb->sb_mnt_count, 1);
  	STORE_LE(sb->sb_max_mnt_count, DEFAULT_MAX_MNT_COUNT);
  	STORE_LE(sb->sb_umount_state, FS_CLEANLY_UMOUNTED);
  	STORE_LE(sb->sb_tree_height, 2);
  	STORE_LE(sb->sb_hash_function_code, 3); // R5_HASH
  	STORE_LE(sb->sb_flags, 1);
  	//STORE_LE(sb->sb_reserved_for_journal, 0);
  	// create UUID
  	generate_uuid(sb->s_uuid);
  	// write the label
  	safe_strncpy((char *)sb->s_label, label, sizeof(sb->s_label));
  
  	// TODO: EMPIRIC! ENDIANNESS!
  	// superblock has only 204 bytes. What are these?
  	buf = (uint8_t *)sb;
  	buf[205] = 1;
  	buf[209] = 3;
  
  	// put superblock
  	xwrite(fd, sb, blocksize);
  
  	// create bitmaps
  	buf = xzalloc(blocksize);
  
  	// bitmap #0 uses initial "block"+1 blocks
  	i = block + 1;
  	memset(buf, 0xFF, i / 8);
  	buf[i / 8] = (1 << (i & 7)) - 1; //0..7 => 00000000..01111111
  	// mark trailing absent blocks, if any
  	if (blocks < 8*blocksize) {
  		unsigned n = 8*blocksize - blocks;
  		i = n / 8;
  		buf[blocksize - i - 1] |= 0x7F00 >> (n & 7); //0..7 => 00000000..11111110
  		memset(buf + blocksize - i, 0xFF, i); // N.B. no overflow here!
  	}
  	// put bitmap #0
  	xwrite(fd, buf, blocksize);
  
  	// now go journal blocks
  	memset(buf, 0, blocksize);
  	for (i = 0; i < journal_blocks; i++)
  		xwrite(fd, buf, blocksize);
  	// dump journal control block
  	memcpy(&((struct reiserfs_journal_header *)buf)->jh_journal, &sb->sb_journal, sizeof(sb->sb_journal));
  	xwrite(fd, buf, blocksize);
  
  	// other bitmaps are in every (8*blocksize)-th block
  	// N.B. they use the only block -- namely bitmap itself!
  	buf[0] = 0x01;
  	// put bitmaps
  	for (i = 1; i < bitmap_blocks; i++) {
  		xlseek(fd, i*8*blocksize * blocksize, SEEK_SET);
  		// mark trailing absent blocks, if any
  		if (i == bitmap_blocks - 1 && (blocks % (8*blocksize))) {
  			unsigned n = 8*blocksize - blocks % (8*blocksize);
  			unsigned j = n / 8;
  			buf[blocksize - j - 1] |= 0x7F00 >> (n & 7); //0..7 => 00000000..11111110
  			memset(buf + blocksize - j, 0xFF, j); // N.B. no overflow here!
  		}
  		xwrite(fd, buf, blocksize);
  	}
  
  	// fill root block
  	// block head
  	memset(buf, 0, blocksize);
  	root = (struct block_head *)buf;
  	STORE_LE(root->blk2_level, 1); // leaf node
  	STORE_LE(root->blk2_nr_item, 2); // "." and ".."
  	STORE_LE(root->blk2_free_space, blocksize - sizeof(struct block_head));
  	// item head
  	// root directory
  	// TODO: EMPIRIC! ENDIANNESS!
  	// TODO: indented assignments seem to be timestamps
  buf[4] = 0134;
  buf[24] = 01;
  buf[28] = 02;
  buf[42] = 054;
  buf[44] = 0324;
  buf[45] = 017;
  buf[46] = 01;
  buf[48] = 01;
  buf[52] = 02;
  buf[56] = 01;
  buf[60] = 0364;
  buf[61] = 01;
  buf[64] = 02;
  buf[66] = 060;
  buf[68] = 0244;
  buf[69] = 017;
  buf[4004] = 01;
  buf[4008] = 01;
  buf[4012] = 02;
  buf[4016] = 050;
  buf[4018] = 04;
  buf[4020] = 02;
  buf[4028] = 01;
  buf[4032] = 040;
  buf[4034] = 04;
  
  buf[4036] = 056; buf[4037] = 056;	// ".."
  buf[4044] = 056;			// "."
  
  buf[4052] = 0355;
  buf[4053] = 0101;
  buf[4056] = 03;
  buf[4060] = 060;
  		buf[4076] = 0173;
  		buf[4077] = 0240;
  	buf[4078] = 0344;
  	buf[4079] = 0112;
  		buf[4080] = 0173;
  		buf[4081] = 0240;
  	buf[4082] = 0344;
  	buf[4083] = 0112;
  		buf[4084] = 0173;
  		buf[4085] = 0240;
  	buf[4086] = 0344;
  	buf[4087] = 0112;
  buf[4088] = 01;
  
  	// put root block
  	xlseek(fd, block * blocksize, SEEK_SET);
  	xwrite(fd, buf, blocksize);
  
  	// cleanup
  	if (ENABLE_FEATURE_CLEAN_UP) {
  		free(buf);
  		free(sb);
  	}
  
  	xclose(fd);
  	return EXIT_SUCCESS;
  }
  