firebird-mirror/src/jrd/jio.cpp

/*
 *	PROGRAM:	JRD Access Method
 *	MODULE:		jio.c
 *	DESCRIPTION:	Journal file i/o
 *
 * The contents of this file are subject to the Interbase Public
 * License Version 1.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy
 * of the License at http://www.Inprise.com/IPL.html
 *
 * Software distributed under the License is distributed on an
 * "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express
 * or implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code was created by Inprise Corporation
 * and its predecessors. Portions created by Inprise Corporation are
 * Copyright (C) Inprise Corporation.
 *
 * All Rights Reserved.
 * Contributor(s): ______________________________________.
 *
 * 2002.02.15 Sean Leyne - Code Cleanup, removed obsolete "EPSON" define
 * 2002.02.15 Sean Leyne - Code Cleanup, removed obsolete "DELTA" port
 * 2002.02.15 Sean Leyne - Code Cleanup, removed obsolete "M88K" port
 *
 * 2002.10.29 Sean Leyne - Removed obsolete "Netware" port
 *
 * 2002.10.30 Sean Leyne - Removed support for obsolete "PC_PLATFORM" define
 *
 */

/* NOTE that this module is used only on platforms that use
   VMS style journaling.   At the moment this is limited to
   VMS and MPE XL. */

#include "firebird.h"
#include "../jrd/ib_stdio.h"
#include "../jrd/jrd.h"
#include "../jrd/jrn.h"
#include "gen/codes.h"

#ifdef VMS
#include <file.h>
#include <lckdef.h>
#include "../jrd/vms.h"
#define EVENT_FLAG	15
#define SYS_ERROR	gds_arg_vms
#endif

#ifndef VMS
#include <sys/types.h>

#ifdef SOLARIS
#include <fcntl.h>
#endif

#ifdef SCO_UNIX
#include <fcntl.h>
#include <sys/stat.h>
#endif

#include <sys/file.h>

#define SYS_ERROR	gds_arg_unix
extern int errno;
#endif

#ifndef FILE_OPEN
#define FILE_OPEN(name,access,mask)	open (name, access, mask)
#endif

#ifndef O_BINARY
#define O_BINARY	0
#endif

#define BLOCKS(length)	((length + BLOCK_SIZE - 1) / BLOCK_SIZE)

extern SLONG LOCK_enq();
extern SLONG LOCK_read_data();
DIR JIO_next_dir();
SLONG JIO_rewind();
static SLONG add_database();
static SLONG block_number();
static DIR locate_dir();
static SLONG lookup_id();

/* Lock Block data */

typedef union {
	struct {
		SSHORT segment;
		SSHORT block;
	} data_items;
	SLONG data_long;
} LDATA;


JIO_fini(journal)
	 JRN journal;
{
/**************************************
 *
 *	J I O _ f i n i
 *
 **************************************
 *
 * Functional description
 *	Signoff journal file.
 *
 **************************************/
	LDATA data;
	struct jfh header;
	int status;

	acquire(journal, &data);
	position_and_read(journal, 0L, &header, sizeof(header));
	header.jfh_write_block = data.data_items.block;
	position_and_write(journal, 0L, &header, sizeof(header));

	lock_release(journal);

#ifdef VMS
	status = sys$dassgn(journal->jrn_channel);

	if (!(status & 1))
		error(journal, status, "sys$dassgn", isc_io_access_err);

#endif

#ifndef VMS
	close((int) journal->jrn_channel);
#endif
}


JIO_get_position(journal, data)
	 JRN journal;
	 LDATA *data;
{
/**************************************
 *
 *	J I O _ g e t _ p o s i t i o n
 *
 **************************************
 *
 * Functional description
 *	Get current output position in journal file.  This is
 *	used to implement FLUSH verb in journal server.
 *
 **************************************/

	acquire(journal, data);
	release(journal, data);
}


DIR JIO_next_dir(dir)
	 DIR dir;
{
/**************************************
 *
 *	J I O _ n e x t _ d i r
 *
 **************************************
 *
 * Functional description
 *	Compute address of next directory entry.
 *
 **************************************/
	USHORT length;

	length = sizeof(struct dir) - 1 + dir->dir_length;
	length = (length + 1) & ~1;

	return (DIR) ((TEXT *) dir + length);
}


JIO_open(journal)
	 JRN journal;
{
/**************************************
 *
 *	J I O _ o p e n
 *
 **************************************
 *
 * Functional description
 *
 **************************************/
	TEXT *file_name;
	USHORT new;
	LDATA data;
	struct jfh header;
	int n, mask;

/* Try to open the journal file.  If we can't, try to create it.  If we
   create it, format it.  If we can't open or create, try to open one
   last time. */

	if (new = journal_open(journal, &data)) {
		clear(&header, sizeof(header));
		header.jfh_version = JFH_VERSION;
		header.jfh_free = SEGMENT_SLOTS;
		n = header.jfh_segments[0] = header.jfh_allocation++;
		position_and_write(journal, 0L, &header, sizeof(header));
	}

/* Get intermediate file header */

	position_and_read(journal, 0L, &header, sizeof(header));

	if (header.jfh_version != JFH_VERSION) {
		ERR_post(gds__jrn_format_err, 0);
		/* Msg366 journal file wrong format */
	}

/* Try to get exclusive lock.  If so, do a little cleanup */

	if (lock_exclusive(journal, FALSE)) {
		data.data_items.segment = header.jfh_segments[header.jfh_data];
		if (!new)
			header.jfh_write_block = high_water(journal, &header);
		data.data_items.block = header.jfh_write_block;
		++header.jfh_series;
		position_and_write(journal, 0L, &header, sizeof(header));
	}

	journal->jrn_series = header.jfh_series;
	release(journal, &data);
}


JIO_put(journal, message, size)
	 JRN journal;
	 LTJC *message;
	 USHORT size;
{
/**************************************
 *
 *	J I O _ p u t
 *
 **************************************
 *
 * Functional description
 *	Write a record to the journal file.
 *
 **************************************/
	SLONG block, blocks;
	SSHORT n, fudge;
	struct jrnh dummy;
	LDATA data;
	USHORT waited;

/* Get write lock on journal file.  The lock block will tell us where
   to write next */

	acquire(journal, &data);

/* Do any message processing necessary */

	switch (message->ltjc_header.jrnh_type) {
	case JRN_ENABLE:
		journal->jrn_handle = add_database(journal,
										   message->ltjc_data,
										   message->ltjc_length);
		message->ltjc_header.jrnh_handle = journal->jrn_handle;
		message->ltjc_header.jrnh_series = journal->jrn_series;
		break;

	case JRN_SIGN_ON:
		journal->jrn_handle = lookup_id(journal,
										message->ltjc_data,
										message->ltjc_length);
		if (!journal->jrn_handle) {
			journal->jrn_handle = add_database(journal,
											   message->ltjc_data,
											   message->ltjc_length);
			journal->jrn_dump = -1;
		}
		message->ltjc_header.jrnh_handle = journal->jrn_handle;
		message->ltjc_header.jrnh_series = journal->jrn_series;
		break;
	}

/* Compute next available block.  If there isn't room in this segment, write a
   dummy block to take the extra space, then allocate new data segment. */

	block = block_number(data.data_items.segment, data.data_items.block);
	blocks = (SLONG) (BLOCKS(size));

	if (data.data_items.block + (SSHORT) blocks > SEGMENT_SIZE) {
		if (fudge = SEGMENT_SIZE - data.data_items.block) {
			dummy.jrnh_type = JRN_DUMMY;
			dummy.jrnh_length = BLOCK_SIZE * fudge;
			dummy.jrnh_handle = journal->jrn_handle;
			dummy.jrnh_series = journal->jrn_series;
			position_and_write(journal, block, &dummy, sizeof(struct jrnh));
		}

		waited = 0;
		while ((n = extend_segments(journal)) == -1 && waited < 300) {
			release(journal, &data);
			waited += 10;
			sleep(10);
			acquire(journal, &data);
		}
		if (n == -1)
			ERR_post(gds__jrn_file_full, 0);
		/* Msg840 intermediate journal file full */
		data.data_items.segment = n;
		data.data_items.block = 0;
		block = block_number(data.data_items.segment, data.data_items.block);
	}

	n = (size + 1) & ~1;
	position_and_write(journal, block, message, n);
	data.data_items.block += (SSHORT) blocks;
	release(journal, &data);
}


JIO_read(journal, position, buffer, size)
	 JRN journal;
	 USHORT *position;
	 JRNH *buffer;
	 USHORT size;
{
/**************************************
 *
 *	J I O _ r e a d
 *
 **************************************
 *
 * Functional description
 *	Read a record from the journal file.  Returns the number of bytes read.
 *
 **************************************/
	USHORT length, n, *ptr;
	SLONG block;
	struct jfh header;
	LDATA data;

/* Acquire lock file */

	acquire(journal, &data);

/* Make sure we don't pass writers */

	for (;;) {
		if (position[0] == data.data_items.segment &&
			position[1] >= data.data_items.block) {
			release(journal, &data);
			return 0;
		}
		if (position[1] < SEGMENT_SIZE)
			break;
		position_and_read(journal, 0L, &header, sizeof(header));
		for (ptr = header.jfh_segments; *ptr != position[0]; ++ptr);
		position[0] = ptr[1];
		position[1] = 0;
	}

/* Read first block of record.  This may be too much or too little,
   so we may have to read more */

	block = block_number(position[0], position[1]);
	position_and_read(journal, block, buffer, BLOCK_SIZE);
	length = buffer->jrnh_length;

	if (length > BLOCK_SIZE) {
		n = length - BLOCK_SIZE;
		n = (n + 1) & ~1;
		position_and_read(journal, block + 1, (UCHAR *) buffer + BLOCK_SIZE,
						  n);
	}

/* Update cursor */

	position[1] += BLOCKS(length);

/* Release file and return */

	release(journal, &data);

	return length;
}


JIO_read_header(journal, header, h_length, id_space, i_length)
	 JRN journal;
	 JFH header;
	 USHORT h_length;
	 TEXT *id_space;
	 USHORT i_length;
{
/**************************************
 *
 *	J I O _ r e a d _ h e a d e r
 *
 **************************************
 *
 * Functional description
 *	Read header data.  If lengths are wrong, return FALSE and
 *	give up, otherwise return TRUE.
 *
 **************************************/
	LDATA data;
	USHORT n;

	if (h_length != sizeof(struct jfh))
		return FALSE;

	acquire(journal, &data);
	position_and_read(journal, 0L, header, h_length);

	if (id_space)
		if (n = MIN(i_length, header->jfh_id_space))
			position_and_read(journal, (SLONG) ID_OFFSET, id_space, n);

	release(journal, &data);

	return TRUE;
}


SLONG JIO_rewind(journal, position)
	 JRN journal;
	 USHORT *position;
{
/**************************************
 *
 *	J I O _ r e w i n d
 *
 **************************************
 *
 * Functional description
 *	Prepare to read from journal.  Return current
 *	sequence number.
 *
 **************************************/
	USHORT block, length, n, *ptr;
	struct jfh header;
	LDATA data;
	SLONG sequence;

/* Acquire lock file */

	acquire(journal, &data);
	position_and_read(journal, 0L, &header, sizeof(header));
	position[0] = header.jfh_segments[0];
	position[1] = header.jfh_copy_block;
	sequence = header.jfh_sequence;
	release(journal, &data);

	return sequence;
}


JIO_truncate(journal, position, sequence)
	 JRN journal;
	 USHORT *position;
	 SLONG sequence;
{
/**************************************
 *
 *	J I O _ t r u n c a t e
 *
 **************************************
 *
 * Functional description
 *	Release any data pages up to a given point.
 *
 **************************************/
	USHORT n, length, *ptr, *ptr2, slots[SEGMENT_SLOTS];
	struct jfh header;
	LDATA data;

/* Acquire lock file */

	acquire(journal, &data);
	position_and_read(journal, 0L, &header, sizeof(header));

	for (ptr = header.jfh_segments, ptr2 = slots; *ptr != position[0];)
		*ptr2++ = *ptr++;

	if (n = ptr2 - slots) {
		header.jfh_data -= n;
		length = (header.jfh_data + 1) * sizeof(USHORT);
		move(ptr, header.jfh_segments, length);
		header.jfh_free -= n;
		move(slots, header.jfh_segments + header.jfh_free,
			 n * sizeof(USHORT));
	}

	header.jfh_copy_block = position[1];
	header.jfh_sequence = sequence;
	position_and_write(journal, 0L, &header, sizeof(header));

	release(journal, &data);
}


static acquire(journal, data)
	 JRN journal;
	 LDATA *data;
{
/**************************************
 *
 *	a c q u i r e
 *
 **************************************
 *
 * Functional description
 *	Acquire write lock on journal file, getting lock data block.
 *
 **************************************/

#ifdef VMS
	vms_convert(journal, data, LCK$K_PWMODE, TRUE);
#endif

#ifndef VMS
	LOCK_convert(journal->jrn_lock_id, LCK_PW, TRUE, 0, 0,
				 journal->jrn_status_vector);
	data->data_long = LOCK_read_data(journal->jrn_lock_id);
#endif
}


static SLONG add_database(journal, name_string, name_length)
	 JRN journal;
	 TEXT *name_string;
	 USHORT name_length;
{
/**************************************
 *
 *	a d d _ d a t a b a s e
 *
 **************************************
 *
 * Functional description
 *	Add a new database to journal file.  Return new id.
 *
 **************************************/
	TEXT id_space[ID_SPACE];
	DIR dir, next;
	struct jfh header;
	ULONG id;

	position_and_read(journal, 0L, &header, sizeof(header));
	position_and_read(journal, (SLONG) ID_OFFSET, id_space,
					  header.jfh_id_space);
	delete_dir(&header, id_space, name_string, name_length);
	dir = (DIR) (id_space + header.jfh_id_space);

	dir->dir_id = id = ++header.jfh_next_id;
	dir->dir_length = name_length;
	strncpy(dir->dir_name, name_string, name_length);
	dir->dir_last_page = 0;

	next = JIO_next_dir(dir);
	header.jfh_id_space = (TEXT *) next - id_space;
	position_and_write(journal, (SLONG) ID_OFFSET, id_space,
					   header.jfh_id_space);
	position_and_write(journal, 0L, &header, sizeof(header));

	return id;
}


static SLONG block_number(segment, block)
	 USHORT segment;
	 USHORT block;
{
/**************************************
 *
 *	b l o c k _ n u m b e r
 *
 **************************************
 *
 * Functional description
 *	Translate from (segment, block) to physical block number.
 *
 **************************************/

	return segment * SEGMENT_SIZE + block + SEGMENT_OFFSET;
}


static clear(block, size)
	 UCHAR *block;
	 USHORT size;
{
/**************************************
 *
 *	c l e a r
 *
 **************************************
 *
 * Functional description
 *	Clear a hunk of memory.
 *
 **************************************/

	if (size)
		do
			*block++ = 0;
		while (--size);
}


static delete_dir(header, id_space, name_string, name_length)
	 JFH header;
	 TEXT *id_space;
	 TEXT *name_string;
	 USHORT name_length;
{
/**************************************
 *
 *	d e l e t e _ d i r
 *
 **************************************
 *
 * Functional description
 *	Delete a database entry from the journal file.
 *
 **************************************/
	DIR dir, next;
	USHORT l;

	if (!(dir = locate_dir(header, id_space, name_string, name_length)))
		return FB_FAILURE;

	next = JIO_next_dir(dir);
	l = (TEXT *) next - id_space;
	move(next, dir, header->jfh_id_space - l);
	header->jfh_id_space -= (TEXT *) next - (TEXT *) dir;

	return FB_SUCCESS;
}


static error(journal, value, string, operation)
	 JRN journal;
	 int value;
	 TEXT *string;
	 STATUS operation;
{
/**************************************
 *
 *	e r r o r
 *
 **************************************
 *
 * Functional description
 *	We've had an unexpected error -- punt.
 *
 **************************************/
	SSHORT errcode;

	ERR_post(isc_io_error,
			 gds_arg_string, string,
			 gds_arg_string, journal->jrn_server,
			 isc_arg_gds, operation, SYS_ERROR, value, 0);
}


#ifdef VMS
static extend_file(journal)
	 JRN journal;
{
/**************************************
 *
 *	e x t e n d _ f i l e
 *
 **************************************
 *
 * Functional description
 *	Extend the length of a file on VMS using QIOs.  This is
 *	a royal pain in the tush.
 *
 **************************************/
	USHORT iosb[4], l;
	struct dsc$descriptor_s desc;
	ATR$ atr;
	FIB$ fib;
	FAT$ fat;
	int status, old_size, new_size, delta;
	SCHAR *p;

	ISC_make_desc(&fib, &desc, sizeof(fib));
	atr.atr$w_size = ATR$S_RECATTR;
	atr.atr$w_type = ATR$C_RECATTR;
	atr.atr$l_addr = &fat;
	atr.atr$l_zero = 0;

/* Get current size */

	p = &fib;
	l = sizeof(fib);
	do
		*p++ = 0;
	while (--l);

	move(journal->jrn_did, fib.fib$w_did, sizeof(fib.fib$w_did));
	move(journal->jrn_fid, fib.fib$w_fid, sizeof(fib.fib$w_fid));
	fib.fib$w_nmctl = FIB$M_FINDFID;

	status = sys$qiow(15,		/* Event flag */
					  journal->jrn_channel,	/* Channel */
					  IO$_ACCESS,	/* Function */
					  iosb,		/* IO status block */
					  NULL,		/* AST address */
					  NULL,		/* AST parameter */
					  &desc,	/* P1 (buffer) */
					  NULL,		/* P2 (length) */
					  NULL,		/* P3 (virtual block) */
					  NULL,		/* P4 */
					  &atr,		/* P5 */
					  NULL);	/* P6 */

	if (!(status & 1) || !((status = iosb[0]) & 1))
		error(journal, status, "sys$enqw (journal io$_access)",
			  isc_io_access_err);

	old_size = fat.fat$w_hiblk[1] + (fat.fat$w_hiblk[0] << 16);
	new_size = old_size + MIN(old_size, 16000);
	delta = new_size - old_size;

/* Extend file */

	fib.fib$l_exsz = delta;
	fib.fib$l_exvbn = 0;
	fib.fib$l_acctl = FIB$M_WRITETHRU;
	fib.fib$w_exctl = FIB$M_EXTEND | FIB$M_ALDEF | FIB$M_ALCONB;

	fat.fat$w_efblk[0] = (new_size + 1) >> 16;
	fat.fat$w_efblk[1] = (new_size + 1);

	status = sys$qiow(15,		/* Event flag */
					  journal->jrn_channel,	/* Channel */
					  IO$_MODIFY,	/* Function */
					  iosb,		/* IO status block */
					  NULL,		/* AST address */
					  NULL,		/* AST parameter */
					  &desc,	/* P1 (buffer) */
					  NULL,		/* P2 (length) */
					  NULL,		/* P3 (virtual block) */
					  NULL,		/* P4 */
					  &atr,		/* P5 */
					  NULL);	/* P6 */

	if (!(status & 1) || !((status = iosb[0]) & 1))
		error(journal, status, "sys$enqw (journal io$_modify)",
			  isc_io_access_err);
}
#endif


static extend_segments(journal)
	 JRN journal;
{
/**************************************
 *
 *	e x t e n d _ s e g m e n t s
 *
 **************************************
 *
 * Functional description
 *	Allocate new data segment for journal.  If the file
 *	is full, return -1.
 *
 **************************************/
	USHORT segment, slots;
	struct jfh header;

	position_and_read(journal, 0L, &header, sizeof(header));

/* Find a free segment.  Allocate one if nothing is available */

	if (header.jfh_free < SEGMENT_SLOTS)
		segment = header.jfh_segments[header.jfh_free++];
	else if (header.jfh_data + 1 >= header.jfh_free)
		return -1;
	else
		segment = header.jfh_allocation++;

	header.jfh_segments[++header.jfh_data] = segment;
	header.jfh_write_block = 0;
	position_and_write(journal, 0L, &header, sizeof(header));

	return segment;
}


#ifdef VMS
static journal_open(journal, data)
	 JRN journal;
	 LDATA *data;
{
/**************************************
 *
 *	j o u r n a l _ o p e n   ( V M S )
 *
 **************************************
 *
 * Functional description
 *	Open the journal file.  If a new one is created
 *	return TRUE, otherwise return FALSE.
 *
 **************************************/
	USHORT new, l, iosb[4];
	int status;
	TEXT *address, expanded_name[NAM$C_MAXRSS], *op, lock_string[64], *p, *q;
	struct FAB fab;
	struct NAM nam;
	LKSB lksb;
	ITM items[2];
	struct dsc$descriptor_s string;

	new = FALSE;

	fab = cc$rms_fab;
	nam = cc$rms_nam;
	fab.fab$l_alq = (SEGMENT_OFFSET + SEGMENT_SIZE * 10);
	fab.fab$w_deq = SEGMENT_SIZE * 10;
	fab.fab$l_nam = &nam;
	fab.fab$b_fac = FAB$M_BIO | FAB$M_GET | FAB$M_PUT;
	fab.fab$l_fop = FAB$M_UFO;
	fab.fab$l_fna = journal->jrn_server;
	fab.fab$b_fns = strlen(fab.fab$l_fna);
	fab.fab$b_rfm = FAB$C_UDF;
	fab.fab$b_shr = FAB$M_SHRGET | FAB$M_SHRPUT | FAB$M_UPI;

	nam.nam$l_rsa = expanded_name;
	nam.nam$b_rss = sizeof(expanded_name);

	op = "sys$open";
	status = sys$open(&fab);

/* If the open failed, by creating the file instead */

	if (status == RMS$_FNF) {
		op = "sys$create";
		status = sys$create(&fab);
		new = TRUE;
	}

/* If neither worked, punt */

	if (!(status & 1))
		error(journal, status, op, isc_io_open_err);

	journal->jrn_channel = fab.fab$l_stv;
	move(nam.nam$w_did, journal->jrn_did, sizeof(journal->jrn_did));
	move(nam.nam$w_fid, journal->jrn_fid, sizeof(journal->jrn_fid));

/* Create lock string for journal file.  This is truely a
   pain in the ass since this must work anywhere on a
   cluster */

	items[0].itm_code = DVI$_DEVLOCKNAM;
	items[0].itm_length = sizeof(lock_string);
	items[0].itm_buffer = lock_string;
	items[0].itm_return_length = &l;

	items[1].itm_code = 0;
	items[1].itm_length = 0;
	items[1].itm_buffer = 0;

	status = sys$getdviw(15, journal->jrn_channel, NULL,
						 items, iosb, NULL, NULL, NULL);

	if (status != 1)
		error(journal, status, "sys$getdviw", isc_io_access_err);

	move(nam.nam$w_fid, lock_string + l, sizeof(nam.nam$w_fid));
	ISC_make_desc(lock_string, &string, l + sizeof(nam.nam$w_fid));

	status =
		sys$enqw(EVENT_FLAG, LCK$K_PWMODE, &lksb, LCK$M_SYSTEM | LCK$M_VALBLK,
				 &string, 0,	/* parent lock id */
				 NULL,			/* AST routine when granted */
				 NULL,			/* ast_argument */
				 NULL,			/* ast_routine */
				 NULL, NULL);

	if (!(status & 1))
		error(journal, status, "sys$enqw", isc_io_access_err);

	status = lksb.lksb_status;

	if (status == SS$_VALNOTVALID)
		data->data_long = 0;
	else if (!(status & 1))
		error(journal, status, "sys$enqw", isc_io_access_err);

	journal->jrn_lock_id = lksb.lksb_lock_id;

	if (data)
		data->data_long = lksb.lksb_value[0];

	return new;
}
#endif


#ifndef VMS
static journal_open(journal, data)
	 JRN journal;
	 LDATA *data;
{
/**************************************
 *
 *	j o u r n a l _ o p e n   ( U N I X )
 *
 **************************************
 *
 * Functional description
 *	Open the journal file.  If a new one is created
 *	return TRUE, otherwise return FALSE.
 *
 **************************************/
	USHORT new;
	int n, mask;

	new = FALSE;

/* Try to open the journal file.  If we can't, try to create it.  If we
   create it, format it.  If we can't open or create, try to open one
   last time. */

	n = FILE_OPEN(journal->jrn_server, O_RDWR | O_BINARY, 0666);

	if (n == -1) {
		mask = umask(0);
		n =
			FILE_OPEN(journal->jrn_server,
					  O_RDWR | O_CREAT | O_EXCL | O_BINARY, 0666);
		umask(mask);
		if (n == -1)
			n = FILE_OPEN(journal->jrn_server, O_RDWR | O_BINARY, 0666);
		else
			new = TRUE;
	}

	if (n == -1)
		error(journal, errno, "open", isc_io_open_err);

	journal->jrn_channel = (int *) n;
	lock_create(journal, data);

	return new;
}
#endif


static DIR locate_dir(header, id_space, name_string, name_length)
	 JFH header;
	 TEXT *id_space;
	 TEXT *name_string;
	 USHORT name_length;
{
/**************************************
 *
 *	l o c a t e _ d i r
 *
 **************************************
 *
 * Functional description
 *	Find database entry in database id record.
 *
 **************************************/
	DIR dir, end;

	end = (DIR) (id_space + header->jfh_id_space);

	for (dir = (DIR) id_space; dir < end; dir = JIO_next_dir(dir))
		if (name_length == dir->dir_length
			&& !strncmp(dir->dir_name, name_string, name_length))
			return dir;

	return NULL;
}


#ifdef VMS
static lock_create(journal, data)
	 JRN journal;
	 LDATA *data;
{
/**************************************
 *
 *	l o c k _ c r e a t e   ( V M S )
 *
 **************************************
 *
 * Functional description
 *	Create lock for journal file.
 *
 **************************************/
	struct dsc$descriptor string;
	TEXT filename[256];
	SLONG status;
	LKSB lksb;

	getname(journal->jrn_channel, filename, 1);
	filename[31] = 0;
	ISC_make_desc(filename, &string, 0);

	status =
		sys$enqw(EVENT_FLAG, LCK$K_PWMODE, &lksb, LCK$M_SYSTEM | LCK$M_VALBLK,
				 &string, 0,	/* parent lock id */
				 NULL,			/* AST routine when granted */
				 NULL,			/* ast_argument */
				 NULL,			/* ast_routine */
				 NULL, NULL);

	if (!(status & 1))
		error(journal, status, "sys$enqw", isc_io_access_err);

	status = lksb.lksb_status;

	if (status == SS$_VALNOTVALID)
		data->data_long = 0;
	else if (!(status & 1))
		error(journal, status, "sys$enqw", isc_io_access_err);

	journal->jrn_lock_id = lksb.lksb_lock_id;

	if (data)
		data->data_long = lksb.lksb_value[0];
}
#endif


#ifndef VMS
static lock_create(journal, data)
	 JRN journal;
	 LDATA *data;
{
/**************************************
 *
 *	l o c k _ c r e a t e    ( U N I X )
 *
 **************************************
 *
 * Functional description
 *	Create lock for journal file.
 *
 **************************************/

	journal->jrn_lock_id = LOCK_enq(0L,	/* Prior */
									0L,	/* Parent */
									0,	/* Series */
									journal->jrn_server,	/* Lock string */
									strlen(journal->jrn_server),	/* length of lock string */
									LCK_PW,
									0, 0, 0L, 1, journal->jrn_status_vector);

	data->data_long = LOCK_read_data(journal->jrn_lock_id);
}
#endif


static lock_exclusive(journal, flag)
	 JRN journal;
	 SSHORT flag;
{
/**************************************
 *
 *	l o c k _ e x c l u s i v e
 *
 **************************************
 *
 * Functional description
 *	Try to get an exclusive lock on the journal file, but
 *	don't block trying.  Return TRUE if we succeed, FALSE
 *	otherwise.
 *
 **************************************/
	SSHORT readers, writers;

#ifdef VMS
	return vms_convert(journal, NULL, LCK$K_EXMODE, FALSE);
#endif

#ifndef VMS
	return LOCK_convert(journal->jrn_lock_id, LCK_EX, 0, 0, 0,
						journal->jrn_status_vector);
#endif
}


static lock_release(journal)
	 JRN journal;
{
/**************************************
 *
 *	l o c k _ r e l e a s e
 *
 **************************************
 *
 * Functional description
 *	Release the lock on the journal file.
 *
 **************************************/

#ifdef VMS
	sys$setast(1);
	sys$deq(journal->jrn_lock_id, NULL, NULL, NULL);
#endif

#ifndef VMS
	LOCK_deq(journal->jrn_lock_id);
#endif
}


static SLONG lookup_id(journal, name_string, name_length)
	 JRN journal;
	 TEXT *name_string;
{
/**************************************
 *
 *	l o o k u p _ i d
 *
 **************************************
 *
 * Functional description
 *	Lookup database id.
 *
 **************************************/
	struct jfh header;
	TEXT id_space[ID_SPACE];
	DIR dir;

	position_and_read(journal, 0L, &header, sizeof(header));
	position_and_read(journal, (SLONG) ID_OFFSET, id_space,
					  header.jfh_id_space);

	if (dir = locate_dir(&header, id_space, name_string, name_length))
		return dir->dir_id;

	return 0L;
}


static high_water(journal, header)
	 JRN journal;
	 JFH header;
{
/**************************************
 *
 *	h i g h _ w a t e r
 *
 **************************************
 *
 * Functional description
 *	We have exclusive access to an existing journal file.  It
 *	is possible that the last guy didn't update the "last write"
 *	slot before going away.  Try to find the last valid block
 *	written, and from that, the next block available.
 *
 **************************************/
	USHORT block, segment;
	struct jrnh record;

	segment = header->jfh_segments[header->jfh_data];

	for (block = header->jfh_write_block; block < SEGMENT_SIZE;
		 block += BLOCKS(record.jrnh_length)) {
		position_and_read(journal, block_number(segment, block), &record,
						  sizeof(record));
		if (record.jrnh_type < JRN_ENABLE || record.jrnh_type > JRN_DUMMY
			|| record.jrnh_series != header->jfh_series
			|| record.jrnh_handle > header->jfh_next_id)
			return block;
	}

	return SEGMENT_SIZE;
}


static move(from, to, length)
	 UCHAR *from;
	 UCHAR *to;
	 USHORT length;
{
/**************************************
 *
 *	m o v e
 *
 **************************************
 *
 * Functional description
 *	Move some bytes.
 *
 **************************************/

	if (length)
		do
			*to++ = *from++;
		while (--length);
}


#ifdef VMS
static position_and_read(journal, block, buffer, length)
	 JRN journal;
	 ULONG block;
	 UCHAR *buffer;
	 USHORT length;
{
/**************************************
 *
 *	p o s i t i o n _ a n d _ r e a d   ( V M S )
 *
 **************************************
 *
 * Functional description
 *	Position journal file to particular block and read record.
 *
 **************************************/
	SSHORT iosb[4];
	int status;

	if (!length)
		return;

	status = sys$qiow(15,		/* Event flag */
					  journal->jrn_channel,	/* Channel */
					  IO$_READVBLK,	/* Function */
					  iosb,		/* IO status block */
					  NULL,		/* AST address */
					  NULL,		/* AST parameter */
					  buffer,	/* P1 (buffer) */
					  length,	/* P2 (length) */
					  block + 1,	/* P3 (virtual block) */
					  NULL, NULL, NULL);

	if (status == SS$_ENDOFFILE) {
		do
			*buffer++ = 0;
		while (--length);
		return;
	}

	if (!(status & 1))
		error(journal, status, "sys$qiow (journal read)", isc_io_read_err);
}
#endif


#ifndef VMS
static position_and_read(journal, block, buffer, length)
	 JRN journal;
	 ULONG block;
	 UCHAR *buffer;
	 USHORT length;
{
/**************************************
 *
 *	p o s i t i o n _ a n d _ r e a d   ( U N I X )
 *
 **************************************
 *
 * Functional description
 *	Position journal file to particular block and read record.
 *
 **************************************/
	int n;
	SLONG position;

	position = (SLONG) (block * BLOCK_SIZE);
	n = lseek((int) journal->jrn_channel, LSEEK_OFFSET_CAST position, 0);

	if (n == -1)
		error(journal, errno, "lseek", isc_io_read_err);

	n = read((int) journal->jrn_channel, buffer, length);

	if (n == -1)
		error(journal, errno, "read", isc_io_read_err);
}
#endif


#ifdef VMS
static position_and_write(journal, block, buffer, length)
	 JRN journal;
	 ULONG block;
	 UCHAR *buffer;
	 USHORT length;
{
/**************************************
 *
 *	p o s i t i o n _ a n d _ w r i t e   ( V M S )
 *
 **************************************
 *
 * Functional description
 *	Position journal file to particular block and write record.
 *
 **************************************/
	SSHORT iosb[4];
	int status;

	for (;;) {
		status = sys$qiow(15,	/* Event flag */
						  journal->jrn_channel,	/* Channel */
						  IO$_WRITEVBLK,	/* Function */
						  iosb,	/* IO status block */
						  NULL,	/* AST address */
						  NULL,	/* AST parameter */
						  buffer,	/* P1 (buffer) */
						  length,	/* P2 (length) */
						  block + 1,	/* P3 (virtual block) */
						  NULL, NULL, NULL);

		if ((status & 1) && ((status = iosb[0]) & 1))
			break;

		if (status == SS$_ENDOFFILE)
			extend_file(journal);
		else
			error(journal, status, "sys$qiow (journal write)",
				  isc_io_write_err);
	}
}
#endif


#ifndef VMS
static position_and_write(journal, block, buffer, length)
	 JRN journal;
	 ULONG block;
	 UCHAR *buffer;
	 USHORT length;
{
/**************************************
 *
 *	p o s i t i o n _ a n d _ w r i t e   ( u n i x )
 *
 **************************************
 *
 * Functional description
 *	Position journal file to particular block and write record.
 *
 **************************************/
	int position, n;

	position = block * BLOCK_SIZE;
	n = lseek((int) journal->jrn_channel, LSEEK_OFFSET_CAST position, 0);

	if (n == -1)
		error(journal, errno, "lseek", isc_io_write_err);

	n = write((int) journal->jrn_channel, buffer, length);

	if (n == -1)
		error(journal, errno, "write", isc_io_write_err);
}
#endif


static release(journal, data)
	 JRN journal;
	 LDATA *data;
{
/**************************************
 *
 *	r e l e a s e
 *
 **************************************
 *
 * Functional description
 *	Down grade file and and update lock block.
 *
 **************************************/

#ifdef VMS
	vms_convert(journal, data, LCK$K_CRMODE, TRUE);
#endif

#ifndef VMS
	LOCK_write_data(journal->jrn_lock_id, data->data_long);
	LOCK_convert(journal->jrn_lock_id, LCK_SR, TRUE, 0, 0,
				 journal->jrn_status_vector);
#endif
}


#ifdef VMS
static vms_convert(journal, data, mode, wait)
	 JRN journal;
	 LDATA *data;
{
/**************************************
 *
 *	v m s _ c o n v e r t
 *
 **************************************
 *
 * Functional description
 *	Acquire write lock on journal file, getting lock data block.
 *
 **************************************/
	SLONG status, flags;
	LKSB lksb;

	lksb.lksb_lock_id = journal->jrn_lock_id;

	if (data) {
		if (mode == LCK$K_PWMODE || mode == LCK$K_EXMODE)
			sys$setast(0);
		lksb.lksb_value[0] = data->data_long;
	}

	flags = LCK$M_CONVERT;

	if (data)
		flags |= LCK$M_VALBLK;

	if (!wait)
		flags |= LCK$M_NOQUEUE;

	status = sys$enqw(EVENT_FLAG, mode, &lksb, flags, NULL, NULL, NULL,	/* AST routine when granted */
					  NULL,		/* ast_argument */
					  NULL,		/* ast_routine */
					  NULL, NULL);

	if (!wait && status == SS$_NOTQUEUED)
		return FALSE;

	if (!(status & 1))
		error(journal, status, "sys$enqw", isc_io_access_err);

	status = lksb.lksb_status;

	if (!(status & 1))
		error(journal, status, "sys$enqw", isc_io_access_err);

	if (data) {
		data->data_long = lksb.lksb_value[0];
		if (!(mode == LCK$K_PWMODE || mode == LCK$K_EXMODE))
			sys$setast(1);
	}

	return TRUE;
}
#endif