/**
 * libf2fs.c
 *
 * Copyright (c) 2013 Samsung Electronics Co., Ltd.
 *             http://www.samsung.com/
 *
 * Dual licensed under the GPL or LGPL version 2 licenses.
 */
#define _LARGEFILE64_SOURCE

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <mntent.h>
#include <time.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <sys/ioctl.h>
#include <linux/hdreg.h>

#include <f2fs_fs.h>

/*
 * UTF conversion codes are Copied from exfat tools.
 */
static const char *utf8_to_wchar(const char *input, wchar_t *wc,
		size_t insize)
{
	if ((input[0] & 0x80) == 0 && insize >= 1) {
		*wc = (wchar_t) input[0];
		return input + 1;
	}
	if ((input[0] & 0xe0) == 0xc0 && insize >= 2) {
		*wc = (((wchar_t) input[0] & 0x1f) << 6) |
		       ((wchar_t) input[1] & 0x3f);
		return input + 2;
	}
	if ((input[0] & 0xf0) == 0xe0 && insize >= 3) {
		*wc = (((wchar_t) input[0] & 0x0f) << 12) |
		      (((wchar_t) input[1] & 0x3f) << 6) |
		       ((wchar_t) input[2] & 0x3f);
		return input + 3;
	}
	if ((input[0] & 0xf8) == 0xf0 && insize >= 4) {
		*wc = (((wchar_t) input[0] & 0x07) << 18) |
		      (((wchar_t) input[1] & 0x3f) << 12) |
		      (((wchar_t) input[2] & 0x3f) << 6) |
		       ((wchar_t) input[3] & 0x3f);
		return input + 4;
	}
	if ((input[0] & 0xfc) == 0xf8 && insize >= 5) {
		*wc = (((wchar_t) input[0] & 0x03) << 24) |
		      (((wchar_t) input[1] & 0x3f) << 18) |
		      (((wchar_t) input[2] & 0x3f) << 12) |
		      (((wchar_t) input[3] & 0x3f) << 6) |
		       ((wchar_t) input[4] & 0x3f);
		return input + 5;
	}
	if ((input[0] & 0xfe) == 0xfc && insize >= 6) {
		*wc = (((wchar_t) input[0] & 0x01) << 30) |
		      (((wchar_t) input[1] & 0x3f) << 24) |
		      (((wchar_t) input[2] & 0x3f) << 18) |
		      (((wchar_t) input[3] & 0x3f) << 12) |
		      (((wchar_t) input[4] & 0x3f) << 6) |
		       ((wchar_t) input[5] & 0x3f);
		return input + 6;
	}
	return NULL;
}

static u_int16_t *wchar_to_utf16(u_int16_t *output, wchar_t wc, size_t outsize)
{
	if (wc <= 0xffff) {
		if (outsize == 0)
			return NULL;
		output[0] = cpu_to_le16(wc);
		return output + 1;
	}
	if (outsize < 2)
		return NULL;
	wc -= 0x10000;
	output[0] = cpu_to_le16(0xd800 | ((wc >> 10) & 0x3ff));
	output[1] = cpu_to_le16(0xdc00 | (wc & 0x3ff));
	return output + 2;
}

int utf8_to_utf16(u_int16_t *output, const char *input, size_t outsize,
		size_t insize)
{
	const char *inp = input;
	u_int16_t *outp = output;
	wchar_t wc;

	while (inp - input < insize && *inp) {
		inp = utf8_to_wchar(inp, &wc, insize - (inp - input));
		if (inp == NULL) {
			DBG(0, "illegal UTF-8 sequence\n");
			return -EILSEQ;
		}
		outp = wchar_to_utf16(outp, wc, outsize - (outp - output));
		if (outp == NULL) {
			DBG(0, "name is too long\n");
			return -ENAMETOOLONG;
		}
	}
	*outp = cpu_to_le16(0);
	return 0;
}

static const u_int16_t *utf16_to_wchar(const u_int16_t *input, wchar_t *wc,
		size_t insize)
{
	if ((le16_to_cpu(input[0]) & 0xfc00) == 0xd800) {
		if (insize < 2 || (le16_to_cpu(input[1]) & 0xfc00) != 0xdc00)
			return NULL;
		*wc = ((wchar_t) (le16_to_cpu(input[0]) & 0x3ff) << 10);
		*wc |= (le16_to_cpu(input[1]) & 0x3ff);
		*wc += 0x10000;
		return input + 2;
	} else {
		*wc = le16_to_cpu(*input);
		return input + 1;
	}
}

static char *wchar_to_utf8(char *output, wchar_t wc, size_t outsize)
{
	if (wc <= 0x7f) {
		if (outsize < 1)
			return NULL;
		*output++ = (char) wc;
	} else if (wc <= 0x7ff) {
		if (outsize < 2)
			return NULL;
		*output++ = 0xc0 | (wc >> 6);
		*output++ = 0x80 | (wc & 0x3f);
	} else if (wc <= 0xffff) {
		if (outsize < 3)
			return NULL;
		*output++ = 0xe0 | (wc >> 12);
		*output++ = 0x80 | ((wc >> 6) & 0x3f);
		*output++ = 0x80 | (wc & 0x3f);
	} else if (wc <= 0x1fffff) {
		if (outsize < 4)
			return NULL;
		*output++ = 0xf0 | (wc >> 18);
		*output++ = 0x80 | ((wc >> 12) & 0x3f);
		*output++ = 0x80 | ((wc >> 6) & 0x3f);
		*output++ = 0x80 | (wc & 0x3f);
	} else if (wc <= 0x3ffffff) {
		if (outsize < 5)
			return NULL;
		*output++ = 0xf8 | (wc >> 24);
		*output++ = 0x80 | ((wc >> 18) & 0x3f);
		*output++ = 0x80 | ((wc >> 12) & 0x3f);
		*output++ = 0x80 | ((wc >> 6) & 0x3f);
		*output++ = 0x80 | (wc & 0x3f);
	} else if (wc <= 0x7fffffff) {
		if (outsize < 6)
			return NULL;
		*output++ = 0xfc | (wc >> 30);
		*output++ = 0x80 | ((wc >> 24) & 0x3f);
		*output++ = 0x80 | ((wc >> 18) & 0x3f);
		*output++ = 0x80 | ((wc >> 12) & 0x3f);
		*output++ = 0x80 | ((wc >> 6) & 0x3f);
		*output++ = 0x80 | (wc & 0x3f);
	} else
		return NULL;

	return output;
}

int utf16_to_utf8(char *output, const u_int16_t *input, size_t outsize,
		size_t insize)
{
	const u_int16_t *inp = input;
	char *outp = output;
	wchar_t wc;

	while (inp - input < insize && le16_to_cpu(*inp)) {
		inp = utf16_to_wchar(inp, &wc, insize - (inp - input));
		if (inp == NULL) {
			DBG(0, "illegal UTF-16 sequence\n");
			return -EILSEQ;
		}
		outp = wchar_to_utf8(outp, wc, outsize - (outp - output));
		if (outp == NULL) {
			DBG(0, "name is too long\n");
			return -ENAMETOOLONG;
		}
	}
	*outp = '\0';
	return 0;
}

int log_base_2(u_int32_t num)
{
	int ret = 0;
	if (num <= 0 || (num & (num - 1)) != 0)
		return -1;

	while (num >>= 1)
		ret++;
	return ret;
}

/*
 * f2fs bit operations
 */
static const int bits_in_byte[256] = {
	0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4,
	1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
	1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
	1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
	3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
	1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
	3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
	3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
	3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
	4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8,
};

int get_bits_in_byte(unsigned char n)
{
	return bits_in_byte[n];
}

int test_and_set_bit_le(u32 nr, u8 *addr)
{
	int mask, retval;

	addr += nr >> 3;
	mask = 1 << ((nr & 0x07));
	retval = mask & *addr;
	*addr |= mask;
	return retval;
}

int test_and_clear_bit_le(u32 nr, u8 *addr)
{
	int mask, retval;

	addr += nr >> 3;
	mask = 1 << ((nr & 0x07));
	retval = mask & *addr;
	*addr &= ~mask;
	return retval;
}

int test_bit_le(u32 nr, const u8 *addr)
{
	return ((1 << (nr & 7)) & (addr[nr >> 3]));
}

int f2fs_test_bit(unsigned int nr, const char *p)
{
	int mask;
	char *addr = (char *)p;

	addr += (nr >> 3);
	mask = 1 << (7 - (nr & 0x07));
	return (mask & *addr) != 0;
}

int f2fs_set_bit(unsigned int nr, char *addr)
{
	int mask;
	int ret;

	addr += (nr >> 3);
	mask = 1 << (7 - (nr & 0x07));
	ret = mask & *addr;
	*addr |= mask;
	return ret;
}

int f2fs_clear_bit(unsigned int nr, char *addr)
{
	int mask;
	int ret;

	addr += (nr >> 3);
	mask = 1 << (7 - (nr & 0x07));
	ret = mask & *addr;
	*addr &= ~mask;
	return ret;
}

static inline u64 __ffs(u8 word)
{
	int num = 0;

	if ((word & 0xf) == 0) {
		num += 4;
		word >>= 4;
	}
	if ((word & 0x3) == 0) {
		num += 2;
		word >>= 2;
	}
	if ((word & 0x1) == 0)
		num += 1;
	return num;
}

/* Copied from linux/lib/find_bit.c */
#define BITMAP_FIRST_BYTE_MASK(start) (0xff << ((start) & (BITS_PER_BYTE - 1)))

static u64 _find_next_bit_le(const u8 *addr, u64 nbits, u64 start, char invert)
{
	u8 tmp;

	if (!nbits || start >= nbits)
		return nbits;

	tmp = addr[start / BITS_PER_BYTE] ^ invert;

	/* Handle 1st word. */
	tmp &= BITMAP_FIRST_BYTE_MASK(start);
	start = round_down(start, BITS_PER_BYTE);

	while (!tmp) {
		start += BITS_PER_BYTE;
		if (start >= nbits)
			return nbits;

		tmp = addr[start / BITS_PER_BYTE] ^ invert;
	}

	return min(start + __ffs(tmp), nbits);
}

u64 find_next_bit_le(const u8 *addr, u64 size, u64 offset)
{
	return _find_next_bit_le(addr, size, offset, 0);
}


u64 find_next_zero_bit_le(const u8 *addr, u64 size, u64 offset)
{
	return _find_next_bit_le(addr, size, offset, 0xff);
}

/*
 * Hashing code adapted from ext3
 */
#define DELTA 0x9E3779B9

static void TEA_transform(unsigned int buf[4], unsigned int const in[])
{
	__u32 sum = 0;
	__u32 b0 = buf[0], b1 = buf[1];
	__u32 a = in[0], b = in[1], c = in[2], d = in[3];
	int     n = 16;

	do {
		sum += DELTA;
		b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
		b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
	} while (--n);

	buf[0] += b0;
	buf[1] += b1;

}

static void str2hashbuf(const unsigned char *msg, int len,
					unsigned int *buf, int num)
{
	unsigned pad, val;
	int i;

	pad = (__u32)len | ((__u32)len << 8);
	pad |= pad << 16;

	val = pad;
	if (len > num * 4)
		len = num * 4;
	for (i = 0; i < len; i++) {
		if ((i % 4) == 0)
			val = pad;
		val = msg[i] + (val << 8);
		if ((i % 4) == 3) {
			*buf++ = val;
			val = pad;
			num--;
		}
	}
	if (--num >= 0)
		*buf++ = val;
	while (--num >= 0)
		*buf++ = pad;

}

/**
 * Return hash value of directory entry
 * @param name          dentry name
 * @param len           name lenth
 * @return              return on success hash value, errno on failure
 */
f2fs_hash_t f2fs_dentry_hash(const unsigned char *name, int len)
{
	__u32 hash;
	f2fs_hash_t	f2fs_hash;
	const unsigned char	*p;
	__u32 in[8], buf[4];

	/* special hash codes for special dentries */
	if ((len <= 2) && (name[0] == '.') &&
		(name[1] == '.' || name[1] == '\0'))
		return 0;

	/* Initialize the default seed for the hash checksum functions */
	buf[0] = 0x67452301;
	buf[1] = 0xefcdab89;
	buf[2] = 0x98badcfe;
	buf[3] = 0x10325476;

	p = name;
	while (1) {
		str2hashbuf(p, len, in, 4);
		TEA_transform(buf, in);
		p += 16;
		if (len <= 16)
			break;
		len -= 16;
	}
	hash = buf[0];

	f2fs_hash = cpu_to_le32(hash & ~F2FS_HASH_COL_BIT);
	return f2fs_hash;
}

unsigned int addrs_per_inode(struct f2fs_inode *i)
{
	if (i->i_inline & F2FS_INLINE_XATTR)
		return DEF_ADDRS_PER_INODE - F2FS_INLINE_XATTR_ADDRS;
	return DEF_ADDRS_PER_INODE;
}

/*
 * CRC32
 */
#define CRCPOLY_LE 0xedb88320

u_int32_t f2fs_cal_crc32(u_int32_t crc, void *buf, int len)
{
	int i;
	unsigned char *p = (unsigned char *)buf;
	while (len--) {
		crc ^= *p++;
		for (i = 0; i < 8; i++)
			crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY_LE : 0);
	}
	return crc;
}

int f2fs_crc_valid(u_int32_t blk_crc, void *buf, int len)
{
	u_int32_t cal_crc = 0;

	cal_crc = f2fs_cal_crc32(F2FS_SUPER_MAGIC, buf, len);

	if (cal_crc != blk_crc)	{
		DBG(0,"CRC validation failed: cal_crc = %u, "
			"blk_crc = %u buff_size = 0x%x\n",
			cal_crc, blk_crc, len);
		return -1;
	}
	return 0;
}

/*
 * device information
 */
void f2fs_init_configuration(struct f2fs_configuration *c)
{
	c->total_sectors = 0;
	c->sector_size = DEFAULT_SECTOR_SIZE;
	c->sectors_per_blk = DEFAULT_SECTORS_PER_BLOCK;
	c->blks_per_seg = DEFAULT_BLOCKS_PER_SEGMENT;

	/* calculated by overprovision ratio */
	c->reserved_segments = 0;
	c->overprovision = 0;
	c->segs_per_sec = 1;
	c->secs_per_zone = 1;
	c->segs_per_zone = 1;
	c->heap = 1;
	c->vol_label = "";
	c->device_name = NULL;
	c->trim = 1;
	c->ro = 0;
}

static int is_mounted(struct f2fs_configuration *c,
				const char *mpt, const char *device)
{
	FILE *file = NULL;
	struct mntent *mnt = NULL;

	file = setmntent(mpt, "r");
	if (file == NULL)
		return 0;

	while ((mnt = getmntent(file)) != NULL) {
		if (!strcmp(device, mnt->mnt_fsname)) {
			if (hasmntopt(mnt, MNTOPT_RO))
				config.ro = 1;
			break;
		}
	}
	endmntent(file);
	return mnt ? 1 : 0;
}

int f2fs_dev_is_umounted(struct f2fs_configuration *c)
{
	struct stat st_buf;
	int ret = 0;

	ret = is_mounted(c, MOUNTED, c->device_name);
	if (ret) {
		MSG(0, "Info: Mounted device!\n");
		return -1;
	}

	/*
	 * if failed due to /etc/mtab file not present
	 * try with /proc/mounts.
	 */
	ret = is_mounted(c, "/proc/mounts", c->device_name);
	if (ret) {
		MSG(0, "Info: Mounted device!\n");
		return -1;
	}

	/*
	 * If f2fs is umounted with -l, the process can still use
	 * the file system. In this case, we should not format.
	 */
	if (stat(c->device_name, &st_buf) == 0 && S_ISBLK(st_buf.st_mode)) {
		int fd = open(c->device_name, O_RDONLY | O_EXCL);

		if (fd >= 0) {
			close(fd);
		} else if (errno == EBUSY) {
			MSG(0, "\tError: In use by the system!\n");
			return -1;
		}
	}
	return 0;
}

void get_kernel_version(__u8 *version)
{
	int i;
	for (i = 0; i < VERSION_LEN; i++) {
		if (version[i] == '\n')
			break;
	}
	memset(version + i, 0, VERSION_LEN + 1 - i);
}

int f2fs_get_device_info(struct f2fs_configuration *c)
{
	int32_t fd = 0;
	uint32_t sector_size;
#ifndef BLKGETSIZE64
	uint32_t total_sectors;
#endif
	struct stat stat_buf;
	struct hd_geometry geom;
	u_int64_t wanted_total_sectors = c->total_sectors;

	fd = open(c->device_name, O_RDWR);
	if (fd < 0) {
		MSG(0, "\tError: Failed to open the device!\n");
		return -1;
	}
	c->fd = fd;

	c->kd = open("/proc/version", O_RDONLY);
	if (c->kd < 0)
		MSG(0, "\tInfo: No support kernel version!\n");

	if (fstat(fd, &stat_buf) < 0 ) {
		MSG(0, "\tError: Failed to get the device stat!\n");
		return -1;
	}

	if (S_ISREG(stat_buf.st_mode)) {
		c->total_sectors = stat_buf.st_size / c->sector_size;
	} else if (S_ISBLK(stat_buf.st_mode)) {
		if (ioctl(fd, BLKSSZGET, &sector_size) < 0) {
			MSG(0, "\tError: Using the default sector size\n");
		} else {
			if (c->sector_size < sector_size) {
				c->sector_size = sector_size;
				c->sectors_per_blk = PAGE_SIZE / sector_size;
			}
		}

#ifdef BLKGETSIZE64
		if (ioctl(fd, BLKGETSIZE64, &c->total_sectors) < 0) {
			MSG(0, "\tError: Cannot get the device size\n");
			return -1;
		}
		c->total_sectors /= c->sector_size;
#else
		if (ioctl(fd, BLKGETSIZE, &total_sectors) < 0) {
			MSG(0, "\tError: Cannot get the device size\n");
			return -1;
		}
		total_sectors /= c->sector_size;
		c->total_sectors = total_sectors;
#endif
		if (ioctl(fd, HDIO_GETGEO, &geom) < 0)
			c->start_sector = 0;
		else
			c->start_sector = geom.start;
	} else {
		MSG(0, "\tError: Volume type is not supported!!!\n");
		return -1;
	}
	if (wanted_total_sectors && wanted_total_sectors < c->total_sectors) {
		MSG(0, "Info: total device sectors = %"PRIu64" (in %u bytes)\n",
					c->total_sectors, c->sector_size);
		c->total_sectors = wanted_total_sectors;

	}
	MSG(0, "Info: sector size = %u\n", c->sector_size);
	MSG(0, "Info: total sectors = %"PRIu64" (%"PRIu64" MB)\n",
				c->total_sectors, (c->total_sectors *
					(c->sector_size >> 9)) >> 11);
	return 0;
}