/*
   Copyright (c) 2005, 2016, Oracle and/or its affiliates. All rights reserved.
   Copyright (c) 2014, 2022, MariaDB Corporation.

   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; version 2 of the License.

   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 St, Fifth Floor, Boston, MA 02110-1335  USA
*/

/*
  InnoDB offline file checksum utility.  85% of the code in this utility
  is included from the InnoDB codebase.

  The final 15% was originally written by Mark Smith of Danga
  Interactive, Inc. <junior@danga.com>

  Published with a permission.
*/

#include <my_global.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#ifndef _WIN32
# include <unistd.h>
#endif
#include <my_getopt.h>
#include <m_string.h>
#include <welcome_copyright_notice.h> /* ORACLE_WELCOME_COPYRIGHT_NOTICE */

/* Only parts of these files are included from the InnoDB codebase.
The parts not included are excluded by #ifndef UNIV_INNOCHECKSUM. */

#include "mach0data.h"
#include "page0page.h"
#include "buf0checksum.h"        /* buf_calc_page_*() */
#include "buf0buf.h"             /* buf_page_is_corrupted */
#include "page0zip.h"            /* page_zip_*() */
#include "trx0undo.h"            /* TRX_* */
#include "fil0crypt.h"           /* fil_space_verify_crypt_checksum */
#include <string.h>

#ifdef UNIV_NONINL
# include "fsp0fsp.inl"
# include "mach0data.inl"
# include "ut0rnd.inl"
#endif

#ifndef PRIuMAX
#define PRIuMAX   "llu"
#endif

/* Global variables */
static bool			verbose;
static bool			just_count;
static uint32_t			start_page;
static uint32_t			end_page;
static uint32_t			do_page;
static bool			use_end_page;
static bool			do_one_page;
static my_bool do_leaf;
static my_bool per_page_details;
static ulint n_merge;
static ulint physical_page_size;  /* Page size in bytes on disk. */
static ulint extent_size;
static ulint xdes_size;
ulong srv_page_size;
uint32_t srv_page_size_shift;
static uint32_t dblwr_1;
static uint32_t dblwr_2;
/* Current page number (0 based). */
uint32_t		cur_page_num;
/* Current space. */
uint32_t		cur_space;
/* Skip the checksum verification. */
static bool			no_check;
/* Enabled for rewrite checksum. */
static bool			do_write;
/* Mismatches count allowed (0 by default). */
static unsigned long long     	allow_mismatches=0;
static bool			page_type_summary;
static bool			page_type_dump;
/* Store filename for page-type-dump option. */
char*				page_dump_filename = 0;
/* skip the checksum verification & rewrite if page is doublewrite buffer. */
static bool			skip_page = 0;
const char			*dbug_setting = "FALSE";
char*				log_filename = NULL;
/* User defined filename for logging. */
FILE*				log_file = NULL;
/* Enabled for log write option. */
static bool			is_log_enabled = false;
static bool			skip_freed_pages;
static uint32_t 		tablespace_flags= 0;
static byte field_ref_zero_buf[UNIV_PAGE_SIZE_MAX];
const byte *field_ref_zero = field_ref_zero_buf;
constexpr uint32_t USE_FSP_FLAGS{UINT32_MAX};

#ifndef _WIN32
/* advisory lock for non-window system. */
struct flock			lk;
#endif /* _WIN32 */

/* Innodb page type. */
struct innodb_page_type {
	int n_undo_state_active;
	int n_undo_state_cached;
	int n_undo_state_to_purge;
	int n_undo_state_prepared;
	int n_undo_state_other;
	int n_undo;
	int n_fil_page_index;
	int n_fil_page_undo_log;
	int n_fil_page_inode;
	int n_fil_page_ibuf_free_list;
	int n_fil_page_ibuf_bitmap;
	int n_fil_page_type_sys;
	int n_fil_page_type_trx_sys;
	int n_fil_page_type_fsp_hdr;
	int n_fil_page_type_allocated;
	int n_fil_page_type_xdes;
	int n_fil_page_type_blob;
	int n_fil_page_type_zblob;
	int n_fil_page_type_other;
	int n_fil_page_type_zblob2;
	int n_fil_page_type_page_compressed;
	int n_fil_page_type_page_compressed_encrypted;
} page_type;

#define SIZE_RANGES_FOR_PAGE 10
#define NUM_RETRIES 3
#define DEFAULT_RETRY_DELAY 1000000

struct per_page_stats {
  ulint n_recs;
  ulint data_size;
  ulint left_page_no;
  ulint right_page_no;
  per_page_stats(ulint n, ulint data, ulint left, ulint right) :
      n_recs(n), data_size(data), left_page_no(left), right_page_no(right) {}
  per_page_stats() : n_recs(0), data_size(0), left_page_no(0), right_page_no(0) {}
};

struct per_index_stats {
  unsigned long long pages;
  unsigned long long leaf_pages;
  ulint first_leaf_page;
  ulint count;
  ulint free_pages;
  ulint max_data_size;
  unsigned long long total_n_recs;
  unsigned long long total_data_bytes;

  /*!< first element for empty pages,
  last element for pages with more than logical_page_size */
  unsigned long long pages_in_size_range[SIZE_RANGES_FOR_PAGE+2];

  std::map<unsigned long long, per_page_stats> leaves;

  per_index_stats():pages(0), leaf_pages(0), first_leaf_page(0),
                    count(0), free_pages(0), max_data_size(0), total_n_recs(0),
                    total_data_bytes(0)
  {
    memset(pages_in_size_range, 0, sizeof(pages_in_size_range));
  }
};

std::map<unsigned long long, per_index_stats> index_ids;

void print_index_leaf_stats(
	unsigned long long id,
	const per_index_stats& index,
	FILE*	fil_out)

{
	ulint page_no = index.first_leaf_page;
	std::map<unsigned long long, per_page_stats>::const_iterator it_page = index.leaves.find(page_no);
	fprintf(fil_out, "\nindex: %llu leaf page stats: n_pages = %llu\n",
		id, index.leaf_pages);
	fprintf(fil_out, "page_no\tdata_size\tn_recs\n");
	while (it_page != index.leaves.end()) {
		const per_page_stats& stat = it_page->second;
		fprintf(fil_out, "%llu\t" ULINTPF "\t" ULINTPF "\n", it_page->first, stat.data_size, stat.n_recs);
		page_no = stat.right_page_no;
		it_page = index.leaves.find(page_no);
	}
}

void defrag_analysis(
	unsigned long long id,
	const per_index_stats& index,
	FILE*	fil_out)
{
	// TODO: make it work for compressed pages too
	std::map<unsigned long long, per_page_stats>::const_iterator it = index.leaves.find(index.first_leaf_page);
	ulint n_pages = 0;
	ulint n_leaf_pages = 0;
	while (it != index.leaves.end()) {
		ulint data_size_total = 0;
		for (ulong i = 0; i < n_merge; i++) {
			const per_page_stats& stat = it->second;
			n_leaf_pages ++;
			data_size_total += stat.data_size;
			it = index.leaves.find(stat.right_page_no);
			if (it == index.leaves.end()) {
				break;
			}
		}

		if (index.max_data_size) {
			n_pages += data_size_total / index.max_data_size;
			if (data_size_total % index.max_data_size != 0) {
				n_pages += 1;
			}
		}
	}

	if (index.leaf_pages) {
		fprintf(fil_out, "count = " ULINTPF " free = " ULINTPF "\n", index.count, index.free_pages);
	}

	if (!n_leaf_pages) {
		n_leaf_pages = 1;
	}

	fprintf(fil_out, "%llu\t\t%llu\t\t" ULINTPF "\t\t" ULINTPF "\t\t" ULINTPF "\t\t%.2f\t" ULINTPF "\n",
		id, index.leaf_pages, n_leaf_pages, n_merge, n_pages,
		1.0 - (double)n_pages / (double)n_leaf_pages, index.max_data_size);
}

void print_leaf_stats(
	FILE*	fil_out)
{
	fprintf(fil_out, "\n**************************************************\n");
	fprintf(fil_out, "index_id\t#leaf_pages\t#actual_leaf_pages\tn_merge\t"
		"#leaf_after_merge\tdefrag\n");
	for (std::map<unsigned long long, per_index_stats>::const_iterator it = index_ids.begin();
	     it != index_ids.end(); it++) {
		const per_index_stats& index = it->second;

		if (verbose) {
			print_index_leaf_stats(it->first, index, fil_out);
		}

		if (n_merge) {
			defrag_analysis(it->first, index, fil_out);
		}
	}
}

/** Init the page size for the tablespace.
@param[in]	flags	InnoDB tablespace flags */
static void init_page_size_from_flags(const uint32_t flags)
{
	if (fil_space_t::full_crc32(flags)) {
		const uint32_t ssize = FSP_FLAGS_FCRC32_GET_PAGE_SSIZE(flags);
		srv_page_size_shift = UNIV_ZIP_SIZE_SHIFT_MIN - 1 + ssize;
		srv_page_size = 512U << ssize;
		physical_page_size = srv_page_size;
		extent_size = FSP_EXTENT_SIZE;
		xdes_size = XDES_SIZE;
		return;
	}

	const uint32_t ssize = FSP_FLAGS_GET_PAGE_SSIZE(flags);

	srv_page_size_shift = ssize
		? UNIV_ZIP_SIZE_SHIFT_MIN - 1 + ssize
		: UNIV_PAGE_SIZE_SHIFT_ORIG;

	srv_page_size = fil_space_t::logical_size(flags);
	physical_page_size = fil_space_t::physical_size(flags);
	extent_size = FSP_EXTENT_SIZE;
	xdes_size = XDES_SIZE;
}

#ifdef _WIN32
/***********************************************//*
 @param		[in] error	error no. from the getLastError().

 @retval error message corresponding to error no.
*/
static
char*
error_message(
	int	error)
{
	static char err_msg[1024] = {'\0'};
	FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM,
		NULL, error, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
		(LPTSTR)err_msg, sizeof(err_msg), NULL );

	return (err_msg);
}
#endif /* _WIN32 */

/***********************************************//*
 @param>>_______[in] name>_____name of file.
 @retval file pointer; file pointer is NULL when error occurred.
*/

FILE*
open_file(
	const char*	name)
{
	int	fd;		/* file descriptor. */
	FILE*	fil_in;
#ifdef _WIN32
	HANDLE		hFile;		/* handle to open file. */
	DWORD		access;		/* define access control */
	int		flags = 0;	/* define the mode for file
					descriptor */

	if (do_write) {
		access =  GENERIC_READ | GENERIC_WRITE;
		flags =  _O_RDWR | _O_BINARY;
	} else {
		access = GENERIC_READ;
		flags = _O_RDONLY | _O_BINARY;
	}

	/* CreateFile() also provide advisory lock with the usage of
	access and share mode of the file.*/
	hFile = CreateFile(
			(LPCTSTR) name, access, 0L, NULL,
			OPEN_EXISTING, NULL, NULL);

	if (hFile == INVALID_HANDLE_VALUE) {
		/* print the error message. */
		fprintf(stderr, "Filename::%s %s\n", name,
			error_message(GetLastError()));

			return (NULL);
		}

	/* get the file descriptor. */
	fd= _open_osfhandle((intptr_t)hFile, flags);
#else /* _WIN32 */

	int	create_flag;
	/* define the advisory lock and open file mode. */
	if (do_write) {
		create_flag = O_RDWR;
		lk.l_type = F_WRLCK;
	} else {
		create_flag = O_RDONLY;
		lk.l_type = F_RDLCK;
	}

	fd = open(name, create_flag);

	lk.l_whence = SEEK_SET;
	lk.l_start = lk.l_len = 0;

	if (fcntl(fd, F_SETLK, &lk) == -1) {
		fprintf(stderr, "Error: Unable to lock file::"
			" %s\n", name);
		perror("fcntl");
		return (NULL);
	}
#endif /* _WIN32 */

	if (do_write) {
		fil_in = fdopen(fd, "rb+");
	} else {
		fil_in = fdopen(fd, "rb");
	}

	return (fil_in);
}

/************************************************************//*
 Read the content of file

 @param  [in,out]	buf			read the file in buffer
 @param  [in]		partial_page_read	enable when to read the
						remaining buffer for first page.
 @param  [in]		physical_page_size	Physical/Commpressed page size.
 @param  [in,out]	fil_in			file pointer created for the
						tablespace.
 @retval no. of bytes read.
*/
ulint read_file(
	byte*	buf,
	bool	partial_page_read,
	ulint	physical_page_size,
	FILE*	fil_in)
{
	ulint bytes = 0;

	DBUG_ASSERT(physical_page_size >= UNIV_ZIP_SIZE_MIN);

	if (partial_page_read) {
		buf += UNIV_ZIP_SIZE_MIN;
		physical_page_size -= UNIV_ZIP_SIZE_MIN;
		bytes = UNIV_ZIP_SIZE_MIN;
	}

	bytes += ulint(fread(buf, 1, physical_page_size, fil_in));

	return bytes;
}

/** Check whether the page contains all zeroes.
@param[in]	buf	page
@param[in]	size	physical size of the page
@return true if the page is all zeroes; else false */
static bool is_page_all_zeroes(
	byte*	buf,
	ulint	size)
{
	/* On pages that are not all zero, the page number
	must match. */
	const ulint* p = reinterpret_cast<const ulint*>(buf);
	const ulint* const end = reinterpret_cast<const ulint*>(buf + size);
	do {
		if (*p++) {
			return false;
		}
	} while (p != end);

	return true;
}

/** Check if page is corrupted or not.
@param[in]	buf		page frame
@param[in]	is_encrypted	true if page0 contained cryp_data
				with crypt_scheme encrypted
@param[in]	flags		tablespace flags
@retval true if page is corrupted otherwise false. */
static bool is_page_corrupted(byte *buf, bool is_encrypted, uint32_t flags)
{

	/* enable if page is corrupted. */
	bool is_corrupted;
	/* use to store LSN values. */
	uint32_t logseq;
	uint32_t logseqfield;
	const uint16_t page_type = mach_read_from_2(buf+FIL_PAGE_TYPE);
	uint32_t key_version = buf_page_get_key_version(buf, flags);
	uint32_t space_id = mach_read_from_4(
		buf + FIL_PAGE_ARCH_LOG_NO_OR_SPACE_ID);
	ulint zip_size = fil_space_t::zip_size(flags);
	ulint is_compressed = fil_space_t::is_compressed(flags);
	const bool use_full_crc32 = fil_space_t::full_crc32(flags);

	if (mach_read_from_4(buf + FIL_PAGE_OFFSET) != cur_page_num
	    || (space_id != cur_space
		&& (!use_full_crc32 || (!is_encrypted && !is_compressed)))) {
		/* On pages that are not all zero, the page number
		must match. */
		if (is_page_all_zeroes(buf,
				       fil_space_t::physical_size(flags))) {
			return false;
		}

		if (is_log_enabled) {
			fprintf(log_file,
				"page id mismatch space::" UINT32PF
				" page::" UINT32PF " \n",
				space_id, cur_page_num);
		}

		return true;
	}

	/* We can't trust only a page type, thus we take account
	also fsp_flags or crypt_data on page 0 */
	if ((page_type == FIL_PAGE_PAGE_COMPRESSED && is_compressed) ||
	    (page_type == FIL_PAGE_PAGE_COMPRESSED_ENCRYPTED &&
	     is_compressed && is_encrypted)) {
		/* Page compressed tables do not contain post compression
		checksum. */
		return (false);
	}

	if (!zip_size && (!is_compressed || !use_full_crc32)) {
		/* check the stored log sequence numbers
		for uncompressed tablespace. */
		logseq = mach_read_from_4(buf + FIL_PAGE_LSN + 4);
		logseqfield = use_full_crc32
			? mach_read_from_4(buf + srv_page_size
					   - FIL_PAGE_FCRC32_END_LSN)
			: mach_read_from_4(buf + srv_page_size
					   - FIL_PAGE_END_LSN_OLD_CHKSUM + 4);

		if (is_log_enabled) {
			fprintf(log_file,
				"space::" UINT32PF " page::" UINT32PF
				"; log sequence number:first = " UINT32PF
				"; second = " UINT32PF "\n",
				space_id, cur_page_num, logseq, logseqfield);
			if (logseq != logseqfield) {
				fprintf(log_file,
					"Fail; space::" UINT32PF
					" page::" UINT32PF
					" invalid (fails log "
					"sequence number check)\n",
					space_id, cur_page_num);
			}
		}
	}

	/* Again we can't trust only FIL_PAGE_FILE_FLUSH_LSN field
	now repurposed as FIL_PAGE_FILE_FLUSH_LSN_OR_KEY_VERSION,
	we need to check also crypt_data contents.

	If page is encrypted, use different checksum calculation
	as innochecksum can't decrypt pages. Note that some old InnoDB
	versions did not initialize FIL_PAGE_FILE_FLUSH_LSN field
	so if crypt checksum does not match we verify checksum using
	normal method. */
	if (is_encrypted && key_version != 0) {
		is_corrupted = use_full_crc32
			? !!buf_page_is_corrupted(false, buf, flags)
			: !fil_space_verify_crypt_checksum(buf, zip_size);

		if (is_corrupted && log_file) {
			fprintf(log_file,
				"[page id: space=" UINT32PF
				", page_number=" UINT32PF "] may be corrupted;"
				" key_version=" UINT32PF "\n",
				space_id, cur_page_num, key_version);
		}
	} else {
		is_corrupted = true;
	}

	if (is_corrupted) {
		is_corrupted = buf_page_is_corrupted(true, buf, flags);
	}

	return(is_corrupted);
}

/** Check if page is doublewrite buffer or not.
@retval true  if page is doublewrite buffer otherwise false. */
static bool is_page_doublewritebuffer()
{
  if (cur_space != 0) return false;
  const uint32_t extent{static_cast<uint32_t>(
    cur_page_num & ~(extent_size - 1))};
  return cur_page_num > FSP_DICT_HDR_PAGE_NO &&
	 extent && (extent == dblwr_1 || extent == dblwr_2);
}

/*******************************************************//*
Check if page is empty or not.
 @param		[in] page		page to checked for empty.
 @param		[in] len	size of page.

 @retval true if page is empty.
 @retval false if page is not empty.
*/
static
bool
is_page_empty(
	const byte*	page,
	size_t		len)
{
	while (len--) {
		if (*page++) {
			return (false);
		}
	}

	return (true);
}

/********************************************************************//**
Rewrite the checksum for the page.
@param	[in/out] page			page buffer
@param	[in] flags			tablespace flags

@retval true  : do rewrite
@retval false : skip the rewrite as checksum stored match with
		calculated or page is doublwrite buffer.
*/
static bool update_checksum(byte* page, uint32_t flags)
{
	ib_uint32_t	checksum = 0;
	byte		stored1[4];	/* get FIL_PAGE_SPACE_OR_CHKSUM field checksum */
	byte		stored2[4];	/* get FIL_PAGE_END_LSN_OLD_CHKSUM field checksum */

	ut_ad(page);
	/* If page is doublewrite buffer, skip the rewrite of checksum. */
	if (skip_page) {
		return (false);
	}

	const bool use_full_crc32 = fil_space_t::full_crc32(flags);
	const bool iscompressed = fil_space_t::zip_size(flags);

	memcpy(stored1, page + FIL_PAGE_SPACE_OR_CHKSUM, 4);
	memcpy(stored2, page + physical_page_size -
	       FIL_PAGE_END_LSN_OLD_CHKSUM, 4);

	/* Check if page is empty, exclude the checksum field */
	if (is_page_empty(page + 4, physical_page_size - 12)
	    && is_page_empty(page + physical_page_size - 4, 4)) {

		memset(page + FIL_PAGE_SPACE_OR_CHKSUM, 0, 4);
		memset(page + physical_page_size -
		       FIL_PAGE_END_LSN_OLD_CHKSUM, 0, 4);

		goto func_exit;
	}

	if (iscompressed) {
		/* ROW_FORMAT=COMPRESSED */
		checksum = page_zip_calc_checksum(page, physical_page_size,
						  false);

		mach_write_to_4(page + FIL_PAGE_SPACE_OR_CHKSUM, checksum);
		if (is_log_enabled) {
			fprintf(log_file, "page::" UINT32PF "; Updated checksum ="
				" " UINT32PF "\n", cur_page_num, checksum);
		}

	} else if (use_full_crc32) {
		ulint payload = buf_page_full_crc32_size(page, NULL, NULL)
			- FIL_PAGE_FCRC32_CHECKSUM;
		checksum = my_crc32c(0, page, payload);
		byte* c = page + payload;
		if (mach_read_from_4(c) == checksum) return false;
		mach_write_to_4(c, checksum);
		if (is_log_enabled) {
			fprintf(log_file, "page::" UINT32PF "; Updated checksum"
				" = %u\n", cur_page_num, checksum);
		}
		return true;
	} else {
		/* page is uncompressed. */

		/* Store the new formula checksum */
		checksum = buf_calc_page_crc32(page);

		mach_write_to_4(page + FIL_PAGE_SPACE_OR_CHKSUM, checksum);
		if (is_log_enabled) {
			fprintf(log_file, "page::" UINT32PF
				"; Updated checksum = " UINT32PF "\n",
				cur_page_num, checksum);
		}

		mach_write_to_4(page + physical_page_size -
				FIL_PAGE_END_LSN_OLD_CHKSUM,checksum);
	}

func_exit:
	/* The following code is to check the stored checksum with the
	calculated checksum. If it matches, then return FALSE to skip
	the rewrite of checksum, otherwise return TRUE. */
	if (iscompressed) {
		if (!memcmp(stored1, page + FIL_PAGE_SPACE_OR_CHKSUM, 4)) {
			return (false);
		}
		return (true);
	}

	if (!memcmp(stored1, page + FIL_PAGE_SPACE_OR_CHKSUM, 4)
	    && !memcmp(stored2, page + physical_page_size -
		       FIL_PAGE_END_LSN_OLD_CHKSUM, 4)) {
		return (false);

	}

	return (true);
}

/**
 Write the content to the file
@param[in]		filename	name of the file.
@param[in,out]		file		file pointer where content
					have to be written
@param[in]		buf		file buffer read
@param[in]		flags		tablespace flags
@param[in,out]		pos		current file position.

@retval true	if successfully written
@retval false	if a non-recoverable error occurred
*/
static
bool
write_file(
	const char*	filename,
	FILE*		file,
	byte*		buf,
	uint32_t	flags,
	fpos_t*		pos)
{
	bool	do_update;

	do_update = update_checksum(buf, flags);

	if (file != stdin) {
		if (do_update) {
			/* Set the previous file pointer position
			saved in pos to current file position. */
			if (0 != fsetpos(file, pos)) {
				perror("fsetpos");
				return(false);
			}
		} else {
			/* Store the current file position in pos */
			if (0 != fgetpos(file, pos)) {
				perror("fgetpos");
				return(false);
			}
			return(true);
		}
	}

	if (physical_page_size
	    != fwrite(buf, 1, physical_page_size,
		      file == stdin ? stdout : file)) {
		fprintf(stderr,
			"Failed to write page::" UINT32PF " to %s: %s\n",
			cur_page_num, filename, strerror(errno));

		return(false);
	}
	if (file != stdin) {
		fflush(file);
		/* Store the current file position in pos */
		if (0 != fgetpos(file, pos)) {
			perror("fgetpos");
			return(false);
		}
	}

	return(true);
}

// checks using current xdes page whether the page is free
static inline bool is_page_free(const byte *xdes, ulint physical_page_size,
                                uint32_t page_no)
{
  const byte *des=
      xdes + XDES_ARR_OFFSET +
      xdes_size * ((page_no & (physical_page_size - 1)) / extent_size);
  return xdes_is_free(des, page_no % extent_size);
}

/*
Parse the page and collect/dump the information about page type
@param [in] page	buffer page
@param [out] xdes	extend descriptor page
@param [in] file	file for diagnosis.
@param [in] is_encrypted  tablespace is encrypted
*/
static void
parse_page(
	const byte*	page,
	byte*		xdes,
	FILE*		file,
	bool is_encrypted)
{
	unsigned long long id;
	uint16_t undo_page_type;
	const char *str;
	ulint n_recs;
	uint32_t page_no, left_page_no, right_page_no;
	ulint data_bytes;
	bool is_leaf;
	ulint size_range_id;

	/* Check whether page is doublewrite buffer. */
	str = skip_page ? "Double_write_buffer" : "-";
	page_no = mach_read_from_4(page + FIL_PAGE_OFFSET);
	if (skip_freed_pages) {

		/** Skip doublewrite pages when -r is enabled */
		if (is_page_doublewritebuffer()) {
			return;
		}

		const byte *des= xdes + XDES_ARR_OFFSET +
			xdes_size * ((page_no & (physical_page_size - 1))
				     / extent_size);
		if (mach_read_from_4(des) != XDES_FSEG &&
		    xdes_is_free(des, page_no % extent_size)) {
			return;
		}
	}

	switch (fil_page_get_type(page)) {

	case FIL_PAGE_INDEX: {
		uint32_t key_version = mach_read_from_4(page + FIL_PAGE_FILE_FLUSH_LSN_OR_KEY_VERSION);
		page_type.n_fil_page_index++;

		/* If page is encrypted we can't read index header */
		if (!is_encrypted) {
			id = mach_read_from_8(page + PAGE_HEADER + PAGE_INDEX_ID);
			n_recs = mach_read_from_2(page + PAGE_HEADER + PAGE_N_RECS);
			page_no = mach_read_from_4(page + FIL_PAGE_OFFSET);
			left_page_no = mach_read_from_4(page + FIL_PAGE_PREV);
			right_page_no = mach_read_from_4(page + FIL_PAGE_NEXT);
			ulint is_comp = mach_read_from_2(page + PAGE_HEADER + PAGE_N_HEAP) & 0x8000;
			ulint level = mach_read_from_2(page + PAGE_HEADER + PAGE_LEVEL);
			ulint garbage = mach_read_from_2(page + PAGE_HEADER + PAGE_GARBAGE);


			data_bytes = (ulint)(mach_read_from_2(page + PAGE_HEADER + PAGE_HEAP_TOP)
				- (is_comp
					? PAGE_NEW_SUPREMUM_END
					: PAGE_OLD_SUPREMUM_END)
				- garbage);

			is_leaf = (!*(const uint16*) (page + (PAGE_HEADER + PAGE_LEVEL)));

			if (file) {
				fprintf(file, "#::" UINT32PF "\t\t|\t\tIndex page\t\t\t|"
					"\tindex id=%llu,", cur_page_num, id);

				fprintf(file,
					" page level=" ULINTPF
					", No. of records=" ULINTPF
					", garbage=" ULINTPF ", %s\n",
					level, n_recs, garbage, str);
			}

			size_range_id = (data_bytes * SIZE_RANGES_FOR_PAGE
				+ srv_page_size - 1) / srv_page_size;

			if (size_range_id > SIZE_RANGES_FOR_PAGE + 1) {
				/* data_bytes is bigger than logical_page_size */
				size_range_id = SIZE_RANGES_FOR_PAGE + 1;
			}
			if (per_page_details) {
				printf("index id=%llu page " UINT32PF " leaf %d n_recs " ULINTPF " data_bytes " ULINTPF
					"\n", id, page_no, is_leaf, n_recs, data_bytes);
			}
			/* update per-index statistics */
			{
				per_index_stats &index = index_ids[id];
				if (is_page_free(xdes, physical_page_size, page_no)) {
					index.free_pages++;
					return;
				}

				index.pages++;

				if (is_leaf) {
					index.leaf_pages++;
					if (data_bytes > index.max_data_size) {
						index.max_data_size = data_bytes;
					}
					struct per_page_stats pp(n_recs, data_bytes,
						left_page_no, right_page_no);

					index.leaves[page_no] = pp;

					if (left_page_no == ULINT32_UNDEFINED) {
						index.first_leaf_page = page_no;
						index.count++;
					}
				}

				index.total_n_recs += n_recs;
				index.total_data_bytes += data_bytes;
				index.pages_in_size_range[size_range_id] ++;
			}
		} else if (file) {
			fprintf(file, "#::" UINT32PF "\t\t|\t\tEncrypted Index page\t\t\t|"
				"\tkey_version " UINT32PF ",%s\n", cur_page_num, key_version, str);
		}

		break;
	}
	case FIL_PAGE_UNDO_LOG:
		page_type.n_fil_page_undo_log++;
		undo_page_type = mach_read_from_2(page +
				     TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_TYPE);
		if (file) {
			fprintf(file, "#::" UINT32PF "\t\t|\t\tUndo log page\t\t\t|",
				cur_page_num);
		}
		page_type.n_undo++;
		undo_page_type = mach_read_from_2(page + TRX_UNDO_SEG_HDR +
						  TRX_UNDO_STATE);
		switch (undo_page_type) {
			case TRX_UNDO_ACTIVE:
				page_type.n_undo_state_active++;
				if (file) {
					fprintf(file, ", %s", "Undo log of "
						"an active transaction");
				}
				break;

			case TRX_UNDO_CACHED:
				page_type.n_undo_state_cached++;
				if (file) {
					fprintf(file, ", %s", "Page is "
						"cached for quick reuse");
				}
				break;

			case TRX_UNDO_TO_PURGE:
				page_type.n_undo_state_to_purge++;
				if (file) {
					fprintf(file, ", %s", "Will be "
						"freed in purge when all undo"
					"data in it is removed");
				}
				break;

			case TRX_UNDO_PREPARED:
				page_type.n_undo_state_prepared++;
				if (file) {
					fprintf(file, ", %s", "Undo log of "
						"an prepared transaction");
				}
				break;

			default:
				page_type.n_undo_state_other++;
				break;
		}
		if(file) {
			fprintf(file, ", %s\n", str);
		}
		break;

	case FIL_PAGE_INODE:
		page_type.n_fil_page_inode++;
		if (file) {
			fprintf(file, "#::" UINT32PF "\t\t|\t\tInode page\t\t\t|"
				"\t%s\n",cur_page_num, str);
		}
		break;

	case FIL_PAGE_IBUF_FREE_LIST:
		page_type.n_fil_page_ibuf_free_list++;
		if (file) {
			fprintf(file, "#::" UINT32PF "\t\t|\t\tInsert buffer free list"
				" page\t|\t%s\n", cur_page_num, str);
		}
		break;

	case FIL_PAGE_TYPE_ALLOCATED:
		page_type.n_fil_page_type_allocated++;
		if (file) {
			fprintf(file, "#::" UINT32PF "\t\t|\t\tFreshly allocated "
				"page\t\t|\t%s\n", cur_page_num, str);
		}
		break;

	case FIL_PAGE_IBUF_BITMAP:
		page_type.n_fil_page_ibuf_bitmap++;
		if (file) {
			fprintf(file, "#::" UINT32PF "\t\t|\t\tInsert Buffer "
				"Bitmap\t\t|\t%s\n", cur_page_num, str);
		}
		break;

	case FIL_PAGE_TYPE_SYS:
		page_type.n_fil_page_type_sys++;
		if (file) {
			fprintf(file, "#::" UINT32PF "\t\t|\t\tSystem page\t\t\t|"
				"\t%s\n", cur_page_num, str);
		}
		break;

	case FIL_PAGE_TYPE_TRX_SYS:
		page_type.n_fil_page_type_trx_sys++;
		if (file) {
			fprintf(file, "#::" UINT32PF "\t\t|\t\tTransaction system "
				"page\t\t|\t%s\n", cur_page_num, str);
		}

		if (cur_space == 0 &&
		    (mach_read_from_4(page + TRX_SYS_DOUBLEWRITE +
			             TRX_SYS_DOUBLEWRITE_MAGIC) ==
		     TRX_SYS_DOUBLEWRITE_MAGIC_N))  {
			dblwr_1 = mach_read_from_4(
					page + TRX_SYS_DOUBLEWRITE +
					TRX_SYS_DOUBLEWRITE_BLOCK1);
			dblwr_2 = mach_read_from_4(
					page + TRX_SYS_DOUBLEWRITE +
					TRX_SYS_DOUBLEWRITE_BLOCK2);
		}
		break;

	case FIL_PAGE_TYPE_FSP_HDR:
		page_type.n_fil_page_type_fsp_hdr++;
		if (file) {
			fprintf(file, "#::" UINT32PF "\t\t|\t\tFile Space "
				"Header\t\t|\t%s\n", cur_page_num, str);
		}
		break;

	case FIL_PAGE_TYPE_XDES:
		page_type.n_fil_page_type_xdes++;
		if (file) {
			fprintf(file, "#::" UINT32PF "\t\t|\t\tExtent descriptor "
				"page\t\t|\t%s\n", cur_page_num, str);
		}
		break;

	case FIL_PAGE_TYPE_BLOB:
		page_type.n_fil_page_type_blob++;
		if (file) {
			fprintf(file, "#::" UINT32PF "\t\t|\t\tBLOB page\t\t\t|\t%s\n",
				cur_page_num, str);
		}
		break;

	case FIL_PAGE_TYPE_ZBLOB:
		page_type.n_fil_page_type_zblob++;
		if (file) {
			fprintf(file, "#::" UINT32PF "\t\t|\t\tCompressed BLOB "
				"page\t\t|\t%s\n", cur_page_num, str);
		}
		break;

	case FIL_PAGE_TYPE_ZBLOB2:
		page_type.n_fil_page_type_zblob2++;
		if (file) {
			fprintf(file, "#::" UINT32PF "\t\t|\t\tSubsequent Compressed "
				"BLOB page\t|\t%s\n", cur_page_num, str);
		}
			break;

	case FIL_PAGE_PAGE_COMPRESSED:
		page_type.n_fil_page_type_page_compressed++;
		if (file) {
			fprintf(file, "#::" UINT32PF "\t\t|\t\tPage compressed "
				"page\t|\t%s\n", cur_page_num, str);
		}
		break;

	case FIL_PAGE_PAGE_COMPRESSED_ENCRYPTED:
		page_type.n_fil_page_type_page_compressed_encrypted++;
		if (file) {
			fprintf(file, "#::" UINT32PF "\t\t|\t\tPage compressed encrypted "
				"page\t|\t%s\n", cur_page_num, str);
		}
		break;
	default:
		page_type.n_fil_page_type_other++;
		break;
	}
}
/**
@param [in/out] file_name	name of the filename

@retval FILE pointer if successfully created else NULL when error occurred.
*/
FILE*
create_file(
	char*	file_name)
{
	FILE*	file = NULL;

#ifndef _WIN32
	file = fopen(file_name, "wb");
	if (file == NULL) {
		fprintf(stderr, "Failed to create file: %s: %s\n",
			file_name, strerror(errno));
		return(NULL);
	}
#else
	HANDLE		hFile;		/* handle to open file. */
	int fd = 0;
	hFile = CreateFile((LPCTSTR) file_name,
			  GENERIC_READ | GENERIC_WRITE,
			  FILE_SHARE_READ | FILE_SHARE_DELETE,
			  NULL, CREATE_NEW, NULL, NULL);

	if (hFile == INVALID_HANDLE_VALUE) {
		/* print the error message. */
		fprintf(stderr, "Filename::%s %s\n",
			file_name,
			error_message(GetLastError()));

			return(NULL);
		}

	/* get the file descriptor. */
	fd= _open_osfhandle((intptr_t)hFile, _O_RDWR | _O_BINARY);
	file = fdopen(fd, "wb");
#endif /* _WIN32 */

	return(file);
}

/*
 Print the page type count of a tablespace.
 @param [in] fil_out	stream where the output goes.
*/
void
print_summary(
	FILE*	fil_out)
{
	fprintf(fil_out, "\n================PAGE TYPE SUMMARY==============\n");
	fprintf(fil_out, "#PAGE_COUNT\tPAGE_TYPE");
	fprintf(fil_out, "\n===============================================\n");
	fprintf(fil_out, "%8d\tIndex page\n",
		page_type.n_fil_page_index);
	fprintf(fil_out, "%8d\tUndo log page\n",
		page_type.n_fil_page_undo_log);
	fprintf(fil_out, "%8d\tInode page\n",
		page_type.n_fil_page_inode);
	fprintf(fil_out, "%8d\tInsert buffer free list page\n",
		page_type.n_fil_page_ibuf_free_list);
	fprintf(fil_out, "%8d\tFreshly allocated page\n",
		page_type.n_fil_page_type_allocated);
	fprintf(fil_out, "%8d\tInsert buffer bitmap\n",
		page_type.n_fil_page_ibuf_bitmap);
	fprintf(fil_out, "%8d\tSystem page\n",
		page_type.n_fil_page_type_sys);
	fprintf(fil_out, "%8d\tTransaction system page\n",
		page_type.n_fil_page_type_trx_sys);
	fprintf(fil_out, "%8d\tFile Space Header\n",
		page_type.n_fil_page_type_fsp_hdr);
	fprintf(fil_out, "%8d\tExtent descriptor page\n",
		page_type.n_fil_page_type_xdes);
	fprintf(fil_out, "%8d\tBLOB page\n",
		page_type.n_fil_page_type_blob);
	fprintf(fil_out, "%8d\tCompressed BLOB page\n",
		page_type.n_fil_page_type_zblob);
	fprintf(fil_out, "%8d\tPage compressed page\n",
		page_type.n_fil_page_type_page_compressed);
	fprintf(fil_out, "%8d\tPage compressed encrypted page\n",
		page_type.n_fil_page_type_page_compressed_encrypted);
	fprintf(fil_out, "%8d\tOther type of page\n",
		page_type.n_fil_page_type_other);

	fprintf(fil_out, "\n===============================================\n");
	fprintf(fil_out, "Additional information:\n");
	fprintf(fil_out, "Undo page type: %d\n", page_type.n_undo);
	fprintf(fil_out, "Undo page state: %d active, %d cached, %d"
		" to_purge, %d prepared, %d other\n",
		page_type.n_undo_state_active,
		page_type.n_undo_state_cached,
		page_type.n_undo_state_to_purge,
		page_type.n_undo_state_prepared,
		page_type.n_undo_state_other);

	fprintf(fil_out, "index_id\t#pages\t\t#leaf_pages\t#recs_per_page"
		"\t#bytes_per_page\n");

	for (const auto &ids : index_ids) {
		const per_index_stats& index = ids.second;
		if (!index.pages) {
			DBUG_ASSERT(index.free_pages);
			continue;
		}

		fprintf(fil_out, "%lld\t\t%lld\t\t%lld\t\t%lld\t\t%lld\n",
			ids.first, index.pages, index.leaf_pages,
			index.total_n_recs / index.pages,
			index.total_data_bytes / index.pages);
	}

	fprintf(fil_out, "\n");
	fprintf(fil_out, "index_id\tpage_data_bytes_histgram(empty,...,oversized)\n");

	for (std::map<unsigned long long, per_index_stats>::const_iterator it = index_ids.begin();
	     it != index_ids.end(); it++) {
		fprintf(fil_out, "%lld\t", it->first);
		const per_index_stats& index = it->second;
		for (ulint i = 0; i < SIZE_RANGES_FOR_PAGE+2; i++) {
			fprintf(fil_out, "\t%lld", index.pages_in_size_range[i]);
		}
		fprintf(fil_out, "\n");
	}

	if (do_leaf) {
		print_leaf_stats(fil_out);
	}
}

/* command line argument for innochecksum tool. */
static struct my_option innochecksum_options[] = {
  {"help", '?', "Displays this help and exits.",
    0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
  {"info", 'I', "Synonym for --help.",
    0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
  {"version", 'V', "Displays version information and exits.",
    0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
  {"verbose", 'v', "Verbose (prints progress every 5 seconds).",
    &verbose, &verbose, 0, GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
#ifndef DBUG_OFF
  {"debug", '#', "Output debug log. See https://mariadb.com/kb/en/library/creating-a-trace-file/",
    &dbug_setting, &dbug_setting, 0, GET_STR, OPT_ARG, 0, 0, 0, 0, 0, 0},
#endif /* !DBUG_OFF */
  {"count", 'c', "Print the count of pages in the file and exits.",
    &just_count, &just_count, 0, GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
  {"start_page", 's', "Start on this page number (0 based).",
    &start_page, &start_page, 0, GET_UINT, REQUIRED_ARG,
    0, 0, FIL_NULL, 0, 1, 0},
  {"end_page", 'e', "End at this page number (0 based).",
    &end_page, &end_page, 0, GET_UINT, REQUIRED_ARG,
    0, 0, FIL_NULL, 0, 1, 0},
  {"page", 'p', "Check only this page (0 based).",
    &do_page, &do_page, 0, GET_UINT, REQUIRED_ARG,
    0, 0, FIL_NULL, 0, 1, 0},
  {"no-check", 'n', "Ignore the checksum verification.",
    &no_check, &no_check, 0, GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
  {"allow-mismatches", 'a', "Maximum checksum mismatch allowed.",
    &allow_mismatches, &allow_mismatches, 0,
    GET_ULL, REQUIRED_ARG, 0, 0, ULLONG_MAX, 0, 1, 0},
  {"write", 'w', "Rewrite the checksum.",
    &do_write, &do_write, 0, GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
  {"page-type-summary", 'S', "Display a count of each page type "
   "in a tablespace.", &page_type_summary, &page_type_summary, 0,
   GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
  {"page-type-dump", 'D', "Dump the page type info for each page in a "
   "tablespace.", &page_dump_filename, &page_dump_filename, 0,
   GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
  {"per-page-details", 'i', "Print out per-page detail information.",
   &per_page_details, &per_page_details, 0, GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
   {"log", 'l', "log output.",
     &log_filename, &log_filename, 0,
      GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
  {"leaf", 'f', "Examine leaf index pages",
    &do_leaf, &do_leaf, 0, GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
  {"merge", 'm', "leaf page count if merge given number of consecutive pages",
   &n_merge, &n_merge, 0, GET_ULONG, REQUIRED_ARG, 0, 0, (longlong)10L, 0, 1, 0},
  {"skip-freed-pages", 'r', "skip freed pages for the tablespace",
   &skip_freed_pages, &skip_freed_pages, 0, GET_BOOL, NO_ARG,
   0, 0, 0, 0, 0, 0},
  {"tablespace-flags", 0, "InnoDB tablespace flags (default: 4294967295 "
   "= read from page 0)", &tablespace_flags, &tablespace_flags, 0,
   GET_UINT, REQUIRED_ARG, USE_FSP_FLAGS, 0, USE_FSP_FLAGS, 0, 0, 0},

  {0, 0, 0, 0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0}
};

/** Print out the version and build information. */
static void print_version()
{
#ifdef DBUG_OFF
	printf("%s Ver %s, for %s (%s)\n",
		my_progname, PACKAGE_VERSION,
		SYSTEM_TYPE, MACHINE_TYPE);
#else
	printf("%s-debug Ver %s, for %s (%s)\n",
		my_progname, PACKAGE_VERSION,
		SYSTEM_TYPE, MACHINE_TYPE);
#endif /* DBUG_OFF */
}

static void usage(void)
{
	print_version();
	puts(ORACLE_WELCOME_COPYRIGHT_NOTICE("2000"));
	printf("InnoDB offline file checksum utility.\n");
	printf("Usage: %s [-c] [-r] [-s <start page>] [-e <end page>] "
		"[-p <page>] [-i] [-v]  [-a <allow mismatches>] [-n] "
		"[-S] [-D <page type dump>] "
		"[-l <log>] [-l] [-m <merge pages>] <filename or [-]>\n", my_progname);
	printf("See https://mariadb.com/kb/en/library/innochecksum/"
	       " for usage hints.\n");
	my_print_help(innochecksum_options);
	my_print_variables(innochecksum_options);
}

extern "C" my_bool
innochecksum_get_one_option(
	const struct my_option	*opt,
	const char		*IF_DBUG(argument,),
	const char *)
{
	switch (opt->id) {
#ifndef DBUG_OFF
	case '#':
		dbug_setting = argument
			? argument
			: IF_WIN("d:O,innochecksum.trace",
				 "d:o,/tmp/innochecksum.trace");
		DBUG_PUSH(dbug_setting);
		break;
#endif /* !DBUG_OFF */
	case 'e':
		use_end_page = true;
		break;
	case 'p':
		end_page = start_page = do_page;
		use_end_page = true;
		do_one_page = true;
		break;
	case 'V':
		print_version();
		my_end(0);
		exit(EXIT_SUCCESS);
		break;
	case 'D':
		page_type_dump = true;
		break;
	case 'l':
		is_log_enabled = true;
		break;
	case 'I':
	case '?':
		usage();
		my_end(0);
		exit(EXIT_SUCCESS);
		break;
	default:
	  if (tablespace_flags != USE_FSP_FLAGS &&
	      !fil_space_t::is_valid_flags(tablespace_flags, false) &&
	      !fil_space_t::is_valid_flags(tablespace_flags, true)) {
		fprintf(stderr, "Error: Provided --tablespace-flags "
			"is not valid.");
		return true;
	  }
	}

	return(false);
}

static
bool
get_options(
	int	*argc,
	char	***argv)
{
	if (handle_options(argc, argv, innochecksum_options,
			innochecksum_get_one_option)) {
		my_end(0);
		exit(true);
	}

	/* The next arg must be the filename */
	if (!*argc) {
		usage();
		my_end(0);
		return (true);
	}

	return (false);
}

/** Check from page 0 if table is encrypted.
@param[in]	filename	Filename
@param[in]	page		Page 0
@retval true if tablespace is encrypted, false if not
*/
static bool check_encryption(const char* filename, const byte* page)
{
	ulint offset = FSP_HEADER_OFFSET + XDES_ARR_OFFSET + xdes_size *
		physical_page_size / extent_size;

	if (memcmp(page + offset, CRYPT_MAGIC, MAGIC_SZ) != 0) {
		return false;
	}

	ulint type = mach_read_from_1(page + offset + MAGIC_SZ + 0);

	if (! (type == CRYPT_SCHEME_UNENCRYPTED ||
	       type == CRYPT_SCHEME_1)) {
		return false;
	}

	ulint iv_length = mach_read_from_1(page + offset + MAGIC_SZ + 1);

	if (iv_length != CRYPT_SCHEME_1_IV_LEN) {
		return false;
	}

	uint32_t min_key_version = mach_read_from_4
		(page + offset + MAGIC_SZ + 2 + iv_length);

	uint32_t key_id = mach_read_from_4
		(page + offset + MAGIC_SZ + 2 + iv_length + 4);

	if (type == CRYPT_SCHEME_1 && is_log_enabled) {
		fprintf(log_file,"Tablespace %s encrypted key_version " UINT32PF " key_id " UINT32PF "\n",
			filename, min_key_version, key_id);
	}

	return (type == CRYPT_SCHEME_1);
}

/** Verify page checksum.
@param[in] buf			page to verify
@param[in] zip_size		ROW_FORMAT=COMPRESSED page size, or 0
@param[in] is_encrypted		true if tablespace is encrypted
@param[in,out] mismatch_count	Number of pages failed in checksum verify
@param[in]	flags		tablespace flags
@retval 0 if page checksum matches or 1 if it does not match */
static int verify_checksum(
	byte*			buf,
	bool			is_encrypted,
	unsigned long long*	mismatch_count,
	uint32_t		flags)
{
	int exit_status = 0;
	if (is_page_corrupted(buf, is_encrypted, flags)) {
		fprintf(stderr, "Fail: page::" UINT32PF " invalid\n",
			cur_page_num);

		(*mismatch_count)++;

		if (*mismatch_count > allow_mismatches) {
			fprintf(stderr,
				"Exceeded the "
				"maximum allowed "
				"checksum mismatch "
				"count::%llu current::%llu\n",
				*mismatch_count,
				allow_mismatches);

			exit_status = 1;
		}
	}

	return (exit_status);
}

/** Rewrite page checksum if needed.
@param[in]	filename	File name
@param[in]	fil_in		File pointer
@param[in]	buf		page
@param[in]	pos		File position
@param[in]	is_encrypted	true if tablespace is encrypted
@param[in]	flags		tablespace flags
@retval 0 if checksum rewrite was successful, 1 if error was detected */
static
int
rewrite_checksum(
	const char*	filename,
	FILE*		fil_in,
	byte*		buf,
	fpos_t*		pos,
	bool		is_encrypted,
	uint32_t	flags)
{
	bool is_compressed = fil_space_t::is_compressed(flags);

	/* Rewrite checksum. Note that for encrypted and
	page compressed tables this is not currently supported. */
	return do_write && !is_encrypted && !is_compressed
		&& !write_file(filename, fil_in, buf, flags, pos);
}

/** Read and validate page 0, then initialize tablespace flags
and page size.
@param	fil_in        File pointer
@param	buf           Buffer to read page into
@return whether the page was read successfully */
static bool read_and_validate_page0(FILE *fil_in, byte *buf)
{
  /* Read the minimum page size first */
  size_t initial_page_size= UNIV_ZIP_SIZE_MIN;
  if (tablespace_flags != USE_FSP_FLAGS)
  {
    init_page_size_from_flags(tablespace_flags);
    initial_page_size= physical_page_size;
  }

  /* Read just enough to get the tablespace flags */
  size_t bytes= fread(buf, 1, initial_page_size, fil_in);

  if (bytes != initial_page_size)
  {
    fprintf(stderr, "Error: Was not able to read the "
            "minimum page size of %zu bytes. Bytes read "
            "was %zu\n", initial_page_size, bytes);
    return false;
  }

  /* Read space_id and page offset */
  cur_space= mach_read_from_4(buf + FIL_PAGE_SPACE_ID);
  cur_page_num= mach_read_from_4(buf + FIL_PAGE_OFFSET);

  /* Get tablespace flags from the FSP header */
  uint32_t flags= mach_read_from_4(buf + FSP_HEADER_OFFSET +
                                   FSP_SPACE_FLAGS);

  if (tablespace_flags != USE_FSP_FLAGS)
  {
    if (cur_page_num == 0 && flags != tablespace_flags)
      fprintf(stderr, "Error: Mismatch between provided tablespace "
              "flags (0x%x) and file flags (0x%x)\n",
              tablespace_flags, flags);
  }
  else
  {
    if (cur_page_num)
    {
      fprintf(stderr, "Error: First page of the tablespace file "
              "should be 0, but encountered page number %" PRIu32 ". "
              "If you are checking multi file system "
              "tablespace files, please specify the correct "
              "tablespace flags using --tablespace-flags option.\n",
              cur_page_num);
      return false;
    }
    /* Initialize page size parameters based on flags */
    init_page_size_from_flags(flags);
    /* Read the rest of the page if it's larger than the minimum size */
    if (physical_page_size > UNIV_ZIP_SIZE_MIN)
    {
      /* Read rest of the page 0 to determine crypt_data */
      ulint bytes= read_file(buf, true, physical_page_size, fil_in);
      if (bytes != physical_page_size)
      {
        fprintf(stderr, "Error: Was not able to read the rest of the "
		"page of " ULINTPF " bytes. Bytes read was " ULINTPF "\n",
		physical_page_size - UNIV_ZIP_SIZE_MIN, bytes);
        return false;
      }
    }
    tablespace_flags= flags;
  }

  if (physical_page_size < UNIV_ZIP_SIZE_MIN ||
      physical_page_size > UNIV_PAGE_SIZE_MAX)
  {
    fprintf(stderr, "Error: Invalid page size " ULINTPF
            " encountered\n", physical_page_size);
    return false;
  }
  return true;
}

int main(
	int	argc,
	char	**argv)
{
	/* our input file. */
	FILE*		fil_in = NULL;
	/* our input filename. */
	char*		filename;
	/* Buffer to store pages read. */
	byte*		buf = NULL;
	byte*		xdes = NULL;
	/* bytes read count */
	ulint		bytes;
	/* last time */
	time_t		lastt = 0;
	/* stat, to get file size. */
#ifdef _WIN32
	struct _stat64	st;
#else
	struct stat	st;
#endif /* _WIN32 */

	int exit_status = 0;

	/* size of file (has to be 64 bits) */
	unsigned long long int	size		= 0;
	/* number of pages in file */
	uint32_t	pages;

	off_t		offset			= 0;
	/* count the no. of page corrupted. */
	unsigned long long   mismatch_count		= 0;

	bool		partial_page_read	= false;
	/* Enabled when read from stdin is done. */
	bool		read_from_stdin		= false;
	FILE*		fil_page_type		= NULL;
	fpos_t		pos;

	/* enable when space_id of given file is zero. */
	bool		is_system_tablespace = false;

	MY_INIT(argv[0]);
	DBUG_ENTER("main");
	DBUG_PROCESS(argv[0]);

	if (get_options(&argc,&argv)) {
		exit_status = 1;
		goto my_exit;
	}

	if (no_check && !do_write) {
		fprintf(stderr, "Error: --no-check must be associated with "
			"--write option.\n");
		exit_status = 1;
		goto my_exit;
	}

	if (page_type_dump) {
		fil_page_type = create_file(page_dump_filename);
		if (!fil_page_type) {
			exit_status = 1;
			goto my_exit;
		}
	}

	if (is_log_enabled) {
		log_file = create_file(log_filename);
		if (!log_file) {
			exit_status = 1;
			goto my_exit;
		}
		fprintf(log_file, "InnoDB File Checksum Utility.\n");
	}

	if (verbose) {
		my_print_variables(innochecksum_options);
	}


	buf = static_cast<byte*>(aligned_malloc(UNIV_PAGE_SIZE_MAX,
						UNIV_PAGE_SIZE_MAX));
	xdes = static_cast<byte*>(aligned_malloc(UNIV_PAGE_SIZE_MAX,
						 UNIV_PAGE_SIZE_MAX));

	/* The file name is not optional. */
	for (int i = 0; i < argc; ++i) {

		/* Reset parameters for each file. */
		filename = argv[i];
		memset(&page_type, 0, sizeof(innodb_page_type));
		partial_page_read = false;
		skip_page = false;

		if (is_log_enabled) {
			fprintf(log_file, "Filename = %s\n", filename);
		}

		if (*filename == '-') {
			/* read from stdin. */
			fil_in = stdin;
			read_from_stdin = true;

		}

		/* stat the file to get size and page count. */
		if (!read_from_stdin &&
#ifdef _WIN32
			_stat64(filename, &st)) {
#else
			stat(filename, &st)) {
#endif /* _WIN32 */
			fprintf(stderr, "Error: %s cannot be found\n",
				filename);

			exit_status = 1;
			goto my_exit;
		}

		if (!read_from_stdin) {
			size = st.st_size;
			fil_in = open_file(filename);
			/*If fil_in is NULL, terminate as some error encountered */
			if(fil_in == NULL) {
				exit_status = 1;
				goto my_exit;
			}
			/* Save the current file pointer in pos variable.*/
			if (0 != fgetpos(fil_in, &pos)) {
				perror("fgetpos");
				exit_status = 1;
				goto my_exit;
			}
		}

		/* Read and validate page 0 */
		if (!read_and_validate_page0(fil_in, buf)) {
			exit_status = 1;
			goto my_exit;
		}

		/* Check if tablespace is encrypted */
		bool is_encrypted = check_encryption(filename, buf);

		/* Verify page 0 contents. Note that we can't allow
		checksum mismatch on page 0, because that would mean we
		could not trust it content. */
		if (!no_check) {
			unsigned long long tmp_allow_mismatches = allow_mismatches;
			allow_mismatches = 0;

			exit_status = verify_checksum(buf, is_encrypted,
						      &mismatch_count,
						      tablespace_flags);

			if (exit_status) {
				fprintf(stderr, "Error: Page 0 checksum mismatch, can't continue. \n");
				goto my_exit;
			}
			allow_mismatches = tmp_allow_mismatches;
		}

		if ((exit_status = rewrite_checksum(
					filename, fil_in, buf,
					&pos, is_encrypted,
					tablespace_flags))) {
			goto my_exit;
		}

		if (page_type_dump) {
			fprintf(fil_page_type,
				"\n\nFilename::%s\n", filename);
			fprintf(fil_page_type,
				"========================================"
				"======================================\n");
			fprintf(fil_page_type,
				"\tPAGE_NO\t\t|\t\tPAGE_TYPE\t\t"
				"\t|\tEXTRA INFO\n");
			fprintf(fil_page_type,
				"========================================"
				"======================================\n");
		}

		if (per_page_details) {
			printf("page " UINT32PF " ", cur_page_num);
		}

		memcpy(xdes, buf, physical_page_size);

		if (page_type_summary || page_type_dump) {
			parse_page(buf, xdes, fil_page_type, is_encrypted);
		}

		pages = uint32_t(size / physical_page_size);

		if (just_count) {
			fprintf(read_from_stdin ? stderr : stdout,
				"Number of pages:" UINT32PF "\n", pages);
			continue;
		} else if (verbose && !read_from_stdin) {
			if (is_log_enabled) {
				fprintf(log_file, "file %s = %llu bytes "
					"(" UINT32PF " pages)\n",
					filename, size, pages);
				if (do_one_page) {
					fprintf(log_file, "Innochecksum: "
						"checking page::"
						UINT32PF ";\n",
						do_page);
				}
			}
		} else {
			if (is_log_enabled) {
				fprintf(log_file, "Innochecksum: checking "
					"pages in range::" UINT32PF
					" to " UINT32PF "\n",
					start_page, use_end_page ?
					end_page : (pages - 1));
			}
		}

		off_t cur_offset = 0;
		/* Find the first non all-zero page and fetch the
		space id from there. */
		while (is_page_all_zeroes(buf, physical_page_size)) {
			bytes = ulong(read_file(
					buf, false, physical_page_size,
					fil_in));

			if (feof(fil_in)) {
				fprintf(stderr, "All are "
					"zero-filled pages.");
				goto my_exit;
			}

			cur_offset++;
		}

		cur_space = mach_read_from_4(buf + FIL_PAGE_SPACE_ID);
		is_system_tablespace = (cur_space == 0);

		if (cur_offset > 0) {
			/* Re-read the non-zero page to check the
			checksum. So move the file pointer to
			previous position and reset the page number too. */
			cur_page_num = mach_read_from_4(buf + FIL_PAGE_OFFSET);
			if (!start_page) {
				goto first_non_zero;
			}
		}

		/* seek to the necessary position */
		if (start_page) {
			if (!read_from_stdin) {
				/* If read is not from stdin, we can use
				fseeko() to position the file pointer to
				the desired page. */
				partial_page_read = false;

				offset = off_t(ulonglong(start_page)
					       * physical_page_size);
				if (IF_WIN(_fseeki64,fseeko)(fil_in, offset,
							     SEEK_SET)) {
					perror("Error: Unable to seek to "
						"necessary offset");

					exit_status = 1;
					goto my_exit;
				}
				/* Save the current file pointer in
				pos variable. */
				if (0 != fgetpos(fil_in, &pos)) {
					perror("fgetpos");

					exit_status = 1;
					goto my_exit;
				}
			} else {

				ulong count = 0;

				while (!feof(fil_in)) {
					if (start_page == count) {
						break;
					}
					/* We read a part of page to find the
					minimum page size. We cannot reset
					the file pointer to the beginning of
					the page if we are reading from stdin
					(fseeko() on stdin doesn't work). So
					read only the remaining part of page,
					if partial_page_read is enable. */
					bytes = read_file(buf,
							  partial_page_read,
							  physical_page_size,
							  fil_in);

					partial_page_read = false;
					count++;

					if (!bytes || feof(fil_in)) {
						goto unexpected_eof;
					}
				}
			}
		}

		/* main checksumming loop */
		cur_page_num = start_page ? start_page : cur_page_num + 1;

		while (!feof(fil_in)) {

			bytes = read_file(buf, partial_page_read,
					  physical_page_size, fil_in);
			partial_page_read = false;

			if (!bytes && feof(fil_in)) {
				if (cur_page_num == start_page) {
unexpected_eof:
					fputs("Error: Unable "
					      "to seek to necessary offset\n",
					      stderr);

					exit_status = 1;
					goto my_exit;
				}
				break;
			}

			if (ferror(fil_in)) {
#ifdef _AIX
				/*
				  AIX fseeko can go past eof without error.
				  the error occurs on read, hence output the
				  same error here as would show up on other
				  platforms. This shows up in the mtr test
				  innodb_zip.innochecksum_3-4k,crc32,innodb
				*/
				if (errno == EFBIG) {
					goto unexpected_eof;
				}
#endif
				fprintf(stderr, "Error reading " ULINTPF " bytes",
					physical_page_size);
				perror(" ");

				exit_status = 1;
				goto my_exit;
			}

			if (bytes != physical_page_size) {
				fprintf(stderr, "Error: bytes read (" ULINTPF ") "
					"doesn't match page size (" ULINTPF ")\n",
					bytes, physical_page_size);
				exit_status = 1;
				goto my_exit;
			}

first_non_zero:
			if (is_system_tablespace) {
				/* enable when page is double write buffer.*/
				skip_page = is_page_doublewritebuffer();
			} else {
				skip_page = false;
			}

			const uint16_t cur_page_type = fil_page_get_type(buf);

			/* FIXME: Page compressed or Page compressed and encrypted
			pages do not contain checksum. */
			if (cur_page_type == FIL_PAGE_PAGE_COMPRESSED ||
			    cur_page_type == FIL_PAGE_PAGE_COMPRESSED_ENCRYPTED) {
				skip_page = true;
			}

			/* If no-check is enabled, skip the
			checksum verification.*/
			if (!no_check
			    && !skip_page
			    && !is_page_free(xdes, physical_page_size, cur_page_num)
			    && (exit_status = verify_checksum(
						buf, is_encrypted,
						&mismatch_count,
						tablespace_flags))) {
				goto my_exit;
			}

			if (!is_page_doublewritebuffer() &&
			    (exit_status = rewrite_checksum(
				    filename, fil_in, buf,
				    &pos, is_encrypted,
				    tablespace_flags))) {
				goto my_exit;
			}

			/* end if this was the last page we were supposed to check */
			if (use_end_page && (cur_page_num >= end_page)) {
				break;
			}

			if (per_page_details) {
				printf("page " UINT32PF " ", cur_page_num);
			}

			if (cur_page_num % physical_page_size == 0) {
				memcpy(xdes, buf, physical_page_size);
			}

			if (page_type_summary || page_type_dump) {
				parse_page(buf, xdes, fil_page_type, is_encrypted);
			}

			/* do counter increase and progress printing */
			cur_page_num++;

			if (verbose && !read_from_stdin) {
				if ((cur_page_num % 64) == 0) {
					time_t now = time(0);
					if (!lastt) {
						lastt= now;
					} else if (now - lastt >= 1 && is_log_enabled) {
						fprintf(log_file, "page::" UINT32PF " "
							"okay: %.3f%% done\n",
							(cur_page_num - 1),
							(double) cur_page_num / pages * 100);
						lastt = now;
					}
				}
			}
		}

		if (!read_from_stdin) {
			/* flcose() will flush the data and release the lock if
			any acquired. */
			fclose(fil_in);
		}

		/* Enabled for page type summary. */
		if (page_type_summary) {
			if (!read_from_stdin) {
				fprintf(stdout, "\nFile::%s",filename);
				print_summary(stdout);
			} else {
				print_summary(stderr);
			}
		}
	}

	if (is_log_enabled) {
		fclose(log_file);
	}

	goto common_exit;

my_exit:
	if (!read_from_stdin && fil_in) {
		fclose(fil_in);
	}

	if (log_file) {
		fclose(log_file);
	}

common_exit:
	aligned_free(buf);
	aligned_free(xdes);
	my_end(exit_status);
	DBUG_RETURN(exit_status);
}
