stage2/fsys_jfs.c - grub4dos-solaris - Rivoreo Source Code Repositories

 /* fsys_jfs.c - an implementation for the IBM JFS file system */
 /*
  *  GRUB  --  GRand Unified Bootloader
  *  Copyright (C) 2001,2002  Free Software Foundation, Inc.
  *
  *  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; either version 2 of the License, or
  *  (at your option) any later version.
  *
  *  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., 675 Mass Ave, Cambridge, MA 02139, USA.
  */

 #ifdef FSYS_JFS

 #include "shared.h"
 #include "filesys.h"
 #include "jfs.h"

 #define MAX_LINK_COUNT	8

 #define DTTYPE_INLINE	0
 #define DTTYPE_PAGE	1

 struct jfs_info
 {
 	unsigned long bsize;
 	unsigned long l2bsize;
 	unsigned long bdlog;
 	unsigned long xindex;
 	unsigned long xlastindex;
 	unsigned long sindex;
 	unsigned long slastindex;
 	unsigned long de_index;
 	unsigned long dttype;
 	struct xad *xad;
 	ldtentry_t *de;
 };

 static struct jfs_info jfs;

 #define xtPage		((xtpage_t *)FSYS_BUF)
 #define dtPage		((dtpage_t *)((char *)FSYS_BUF + 4096))
 #define fileSet		((dinode_t *)((char *)FSYS_BUF + 8192))
 #define iNode		((dinode_t *)((char *)FSYS_BUF + 8192 + sizeof(dinode_t)))
 #define dtRoot		((dtroot_t *)(&iNode->di_xtroot))

 #ifndef GRUB_UTIL
 static char *linkbuf = (char *)(FSYS_BUF - JFS_PATH_MAX);	/* buffer for following symbolic links */
 static char *namebuf = (char *)(FSYS_BUF - JFS_PATH_MAX - JFS_NAME_MAX - 1);
 #else
 static char namebuf[JFS_NAME_MAX + 1], linkbuf[JFS_PATH_MAX];
 #endif

 static ldtentry_t de_always[2] = {
 	{1, -1, 2, {'.', '.'}},
 	{1, -1, 1, {'.'}}
 };

 static int
 isinxt (s64 key, s64 offset, s64 len)
 {
 	return (key >= offset) ? (key < offset + len ? 1 : 0) : 0;
 }

 static struct xad *
 first_extent (dinode_t *di)
 {
 	xtpage_t *xtp;

 	jfs.xindex = 2;
 	xtp = (xtpage_t *)&di->di_xtroot;
 	jfs.xad = &xtp->xad[2];
 	if (xtp->header.flag & BT_LEAF) {
 	    	jfs.xlastindex = xtp->header.nextindex;
 	} else {
 		do {
 			devread (addressXAD (jfs.xad) << jfs.bdlog, 0,
 				 sizeof(xtpage_t), (unsigned long long)(unsigned int)(char *)xtPage, 0xedde0d90);
 			jfs.xad = &xtPage->xad[2];
 		} while (!(xtPage->header.flag & BT_LEAF));
 		jfs.xlastindex = xtPage->header.nextindex;
 	}

 	return jfs.xad;
 }

 static struct xad *
 next_extent (void)
 {
 	if (++jfs.xindex < jfs.xlastindex) {
 	} else if (xtPage->header.next) {
 		devread (xtPage->header.next << jfs.bdlog, 0,
 			 sizeof(xtpage_t), (unsigned long long)(unsigned int)(char *)xtPage, 0xedde0d90);
 		jfs.xlastindex = xtPage->header.nextindex;
 		jfs.xindex = XTENTRYSTART;
 		jfs.xad = &xtPage->xad[XTENTRYSTART];
 	} else {
 		return NULL;
 	}
 	return ++jfs.xad;
 }


 static void
 di_read (u32 inum, dinode_t *di)
 {
 	s64 key;
 	u32 xd, ioffset;
 	s64 offset;
 	struct xad *xad;
 	pxd_t pxd;		/* struct size = 8 */

 	key = (((inum >> L2INOSPERIAG) << L2INOSPERIAG) + 4096) >> jfs.l2bsize;
 	xd = (inum & (INOSPERIAG - 1)) >> L2INOSPEREXT;
 	ioffset = ((inum & (INOSPERIAG - 1)) & (INOSPEREXT - 1)) << L2DISIZE;
 	xad = first_extent (fileSet);
 	do {
 		offset = offsetXAD (xad);
 		if (isinxt (key, offset, lengthXAD (xad))) {
 			devread ((addressXAD (xad) + key - offset) << jfs.bdlog,
 				 3072 + xd*sizeof(pxd_t), sizeof(pxd_t), (unsigned long long)(unsigned int)(char *)&pxd, 0xedde0d90);
 			devread (addressPXD (&pxd) << jfs.bdlog,
 				 ioffset, DISIZE, (unsigned long long)(unsigned int)(char *)di, 0xedde0d90);
 			break;
 		}
 	} while ((xad = next_extent ()));
 }

 static ldtentry_t *
 next_dentry (void)
 {
 	ldtentry_t *de;
 	s8 *stbl;

 	if (jfs.dttype == DTTYPE_INLINE) {
 		if (jfs.sindex < jfs.slastindex) {
 			return (ldtentry_t *)&dtRoot->slot[(int)dtRoot->header.stbl[jfs.sindex++]];
 		}
 	} else {
 		de = (ldtentry_t *)dtPage->slot;
 		stbl = (s8 *)&de[(int)dtPage->header.stblindex];
 		if (jfs.sindex < jfs.slastindex) {
 			return &de[(int)stbl[jfs.sindex++]];
 		} else if (dtPage->header.next) {
 			devread (dtPage->header.next << jfs.bdlog, 0,
 				 sizeof(dtpage_t), (unsigned long long)(unsigned int)(char *)dtPage, 0xedde0d90);
 			jfs.slastindex = dtPage->header.nextindex;
 			jfs.sindex = 1;
 			return &de[(int)((s8 *)&de[(int)dtPage->header.stblindex])[0]];
 		}
 	}

 	return (jfs.de_index < 2) ? &de_always[jfs.de_index++] : NULL;
 }

 static ldtentry_t *
 first_dentry (void)
 {
 	dtroot_t *dtr;
 	pxd_t *xd;
 	idtentry_t *de;

 	dtr = (dtroot_t *)&iNode->di_xtroot;
 	jfs.sindex = 0;
 	jfs.de_index = 0;

 	de_always[0].inumber = iNode->di_parent;
 	de_always[1].inumber = iNode->di_number;
 	if (dtr->header.flag & BT_LEAF) {
 		jfs.dttype = DTTYPE_INLINE;
 		jfs.slastindex = dtr->header.nextindex;
 	} else {
 		de = (idtentry_t *)dtPage->slot;
 		jfs.dttype = DTTYPE_PAGE;
 		xd = &((idtentry_t *)dtr->slot)[(int)dtr->header.stbl[0]].xd;
 		for (;;) {
 			devread (addressPXD (xd) << jfs.bdlog, 0,
 				 sizeof(dtpage_t), (unsigned long long)(unsigned int)(char *)dtPage, 0xedde0d90);
 			if (dtPage->header.flag & BT_LEAF)
 				break;
 			xd = &de[(int)((s8 *)&de[(int)dtPage->header.stblindex])[0]].xd;
 		}
 		jfs.slastindex = dtPage->header.nextindex;
 	}

 	return next_dentry ();
 }


 static dtslot_t *
 next_dslot (int next)
 {
 	return (jfs.dttype == DTTYPE_INLINE)
 		? (dtslot_t *)&dtRoot->slot[next]
 		: &((dtslot_t *)dtPage->slot)[next];
 }

 #if 0
 static void
 uni2ansi (UniChar *uni, char *ansi, int len)
 {
 	for (; len; len--, uni++)
 		*ansi++ = (*uni & 0xff80) ? '?' : *(char *)uni;
 }
 #else
 #define uni2ansi unicode_to_utf8
 #endif

 int
 jfs_mount (void)
 {
 	struct jfs_superblock super;	/* struct size = 160 */

 	if ((unsigned long)part_length < MINJFS >> SECTOR_BITS
 	    || !devread (SUPER1_OFF >> SECTOR_BITS, 0,
 			 sizeof(struct jfs_superblock), (unsigned long long)(unsigned int)(char *)&super, 0xedde0d90)
 	    || (super.s_magic != JFS_MAGIC)
 	    || !devread ((AITBL_OFF >> SECTOR_BITS) + FILESYSTEM_I,
 			 0, DISIZE, (unsigned long long)(unsigned int)(char*)fileSet, 0xedde0d90)) {
 		return 0;
 	}

 	jfs.bsize = super.s_bsize;
 	jfs.l2bsize = super.s_l2bsize;
 	jfs.bdlog = jfs.l2bsize - SECTOR_BITS;

 	return 1;
 }

 unsigned long long
 jfs_read (unsigned long long buf, unsigned long long len, unsigned long write)
 {
 	struct xad *xad;
 	s64 endofprev, endofcur;
 	s64 offset, xadlen;
 	unsigned long toread, startpos, endpos;

 	startpos = filepos;
 	endpos = filepos + len;
 	endofprev = (1ULL << 62) - 1;
 	xad = first_extent (iNode);
 	do {
 		offset = offsetXAD (xad);
 		xadlen = lengthXAD (xad);
 		if (isinxt (filepos >> jfs.l2bsize, offset, xadlen)) {
 			endofcur = (offset + xadlen) << jfs.l2bsize;
 			toread = (endofcur >= endpos)
 				  ? len : (endofcur - filepos);

 			disk_read_func = disk_read_hook;
 			devread (addressXAD (xad) << jfs.bdlog,
 				 filepos - (offset << jfs.l2bsize), toread, buf, write);
 			disk_read_func = NULL;

 			if (buf)
 				buf += toread;
 			len -= toread;		/* len always >= 0 */
 			filepos += toread;
 		} else if (offset > endofprev) {
 			toread = ((offset << jfs.l2bsize) >= endpos)
 				  ? len : ((offset - endofprev) << jfs.l2bsize);
 			filepos += toread;
 #if 0
 			{
 				unsigned long tmp_pos = toread;
 				for (; tmp_pos; tmp_pos--) {
 					if (buf)
 						*(buf++) = 0;
 				}
 			}
 #else
 			if (buf)
 			{
 				grub_memset64 (buf, 0, toread);
 				buf += toread;
 			}
 #endif
 			if (len <= toread)
 				break;
 			len -= toread;
 			continue;
 		}
 		endofprev = offset + xadlen;
 		xad = next_extent ();
 	} while (len > 0 && xad);

 	return filepos - startpos;
 }

 int
 jfs_dir (char *dirname)
 {
 	char *ptr, *rest, ch;
 	ldtentry_t *de;
 	dtslot_t *ds;
 	u32 inum, parent_inum;
 	s64 di_size;
 	u32 di_mode;
 	int cmp;
 	unsigned long namlen, n, link_count;
 //	char namebuf[JFS_NAME_MAX + 1], linkbuf[JFS_PATH_MAX];

 	parent_inum = inum = ROOT_I;
 	link_count = 0;
 	for (;;) {
 		di_read (inum, iNode);
 		di_size = iNode->di_size;
 		di_mode = iNode->di_mode;

 		if ((di_mode & IFMT) == IFLNK) {
 			if (++link_count > MAX_LINK_COUNT) {
 				errnum = ERR_SYMLINK_LOOP;
 				return 0;
 			}
 			if (di_size < (di_mode & INLINEEA ? 256 : 128)) {
 				grub_memmove (linkbuf, iNode->di_fastsymlink, di_size);
 				n = di_size;
 			} else if (di_size < JFS_PATH_MAX - 1) {
 				filepos = 0;
 				filemax = di_size;
 				n = jfs_read ((unsigned long long)(unsigned int)linkbuf, filemax, 0xedde0d90);
 			} else {
 				errnum = ERR_FILELENGTH;
 				return 0;
 			}

 			inum = (linkbuf[0] == '/') ? ROOT_I : parent_inum;
 			while (n < (JFS_PATH_MAX - 1) && (linkbuf[n++] = *dirname++));
 			linkbuf[n] = 0;
 			dirname = linkbuf;
 			continue;
 		}

 		if (!*dirname || isspace (*dirname)) {
 			if ((di_mode & IFMT) != IFREG) {
 				errnum = ERR_BAD_FILETYPE;
 				return 0;
 			}
 			filepos = 0;
 			filemax = di_size;
 			return 1;
 		}

 		if ((di_mode & IFMT) != IFDIR) {
 			errnum = ERR_BAD_FILETYPE;
 			return 0;
 		}

 		for (; *dirname == '/'; dirname++);

 		//for (rest = dirname; (ch = *rest) && !isspace (ch) && ch != '/'; rest++);
 		for (rest = dirname; (ch = *rest) && !isspace (ch) && ch != '/'; rest++)
 		{
 			if (ch == '\\')
 			{
 				rest++;
 				if (! (ch = *rest))
 					break;
 			}
 		}

 		*rest = 0;

 		de = first_dentry ();
 		for (;;) {
 			namlen = de->namlen;
 			if (de->next == -1) {
 				uni2ansi (de->name, (unsigned char *)namebuf, namlen);
 				namebuf[namlen] = 0;
 			} else {
 				uni2ansi (de->name, (unsigned char *)namebuf, DTLHDRDATALEN);
 				ptr = namebuf;
 				ptr += DTLHDRDATALEN;
 				namlen -= DTLHDRDATALEN;
 				ds = next_dslot (de->next);
 				while (ds->next != -1) {
 					uni2ansi (ds->name, (unsigned char *)ptr, DTSLOTDATALEN);
 					ptr += DTSLOTDATALEN;
 					namlen -= DTSLOTDATALEN;
 					ds = next_dslot (ds->next);
 				}
 				uni2ansi (ds->name, (unsigned char *)ptr, namlen);
 				ptr += namlen;
 				*ptr = 0;
 			}

 			cmp = (!*dirname) ? -1 : substring (dirname, namebuf, 0);
 #ifndef STAGE1_5
 			if (print_possibilities && ch != '/'
 			    && cmp <= 0) {
 				if (print_possibilities > 0)
 					print_possibilities = -print_possibilities;
 				print_a_completion (namebuf);
 			} else
 #endif
 			if (cmp == 0) {
 				parent_inum = inum;
 				inum = de->inumber;
 		        	*(dirname = rest) = ch;
 				break;
 			}
 			de = next_dentry ();
 			if (de == NULL) {
 				if (print_possibilities < 0)
 					return 1;

 				errnum = ERR_FILE_NOT_FOUND;
 				*rest = ch;
 				return 0;
 			}
 		}
 	}
 }

 unsigned long
 jfs_embed (unsigned long *start_sector, unsigned long needed_sectors)
 {
 	struct jfs_superblock super;	/* struct size = 160 */

 	if (needed_sectors > 63
 	    || !devread (SUPER1_OFF >> SECTOR_BITS, 0,
 			 sizeof (struct jfs_superblock),
 			 (unsigned long long)(unsigned int)(char *)&super, 0xedde0d90)
 	    || (super.s_magic != JFS_MAGIC)) {
 		return 0;
 	}

 	*start_sector = 1;
 	return 1;
 }

 #endif /* FSYS_JFS */
	/* fsys_jfs.c - an implementation for the IBM JFS file system */
	/*
	* GRUB -- GRand Unified Bootloader
	* Copyright (C) 2001,2002 Free Software Foundation, Inc.
	*
	* 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; either version 2 of the License, or
	* (at your option) any later version.
	*
	* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
	*/

	#ifdef FSYS_JFS

	#include "shared.h"
	#include "filesys.h"
	#include "jfs.h"

	#define MAX_LINK_COUNT 8

	#define DTTYPE_INLINE 0
	#define DTTYPE_PAGE 1

	struct jfs_info
	{
	unsigned long bsize;
	unsigned long l2bsize;
	unsigned long bdlog;
	unsigned long xindex;
	unsigned long xlastindex;
	unsigned long sindex;
	unsigned long slastindex;
	unsigned long de_index;
	unsigned long dttype;
	struct xad *xad;
	ldtentry_t *de;
	};

	static struct jfs_info jfs;

	#define xtPage ((xtpage_t *)FSYS_BUF)
	#define dtPage ((dtpage_t )((char )FSYS_BUF + 4096))
	#define fileSet ((dinode_t )((char )FSYS_BUF + 8192))
	#define iNode ((dinode_t )((char )FSYS_BUF + 8192 + sizeof(dinode_t)))
	#define dtRoot ((dtroot_t *)(&iNode->di_xtroot))

	#ifndef GRUB_UTIL
	static char linkbuf = (char )(FSYS_BUF - JFS_PATH_MAX); /* buffer for following symbolic links */
	static char namebuf = (char )(FSYS_BUF - JFS_PATH_MAX - JFS_NAME_MAX - 1);
	#else
	static char namebuf[JFS_NAME_MAX + 1], linkbuf[JFS_PATH_MAX];
	#endif

	static ldtentry_t de_always[2] = {
	{1, -1, 2, {'.', '.'}},
	{1, -1, 1, {'.'}}
	};

	static int
	isinxt (s64 key, s64 offset, s64 len)
	{
	return (key >= offset) ? (key < offset + len ? 1 : 0) : 0;
	}

	static struct xad *
	first_extent (dinode_t *di)
	{
	xtpage_t *xtp;

	jfs.xindex = 2;
	xtp = (xtpage_t *)&di->di_xtroot;
	jfs.xad = &xtp->xad[2];
	if (xtp->header.flag & BT_LEAF) {
	jfs.xlastindex = xtp->header.nextindex;
	} else {
	do {
	devread (addressXAD (jfs.xad) << jfs.bdlog, 0,
	sizeof(xtpage_t), (unsigned long long)(unsigned int)(char *)xtPage, 0xedde0d90);
	jfs.xad = &xtPage->xad[2];
	} while (!(xtPage->header.flag & BT_LEAF));
	jfs.xlastindex = xtPage->header.nextindex;
	}

	return jfs.xad;
	}

	static struct xad *
	next_extent (void)
	{
	if (++jfs.xindex < jfs.xlastindex) {
	} else if (xtPage->header.next) {
	devread (xtPage->header.next << jfs.bdlog, 0,
	sizeof(xtpage_t), (unsigned long long)(unsigned int)(char *)xtPage, 0xedde0d90);
	jfs.xlastindex = xtPage->header.nextindex;
	jfs.xindex = XTENTRYSTART;
	jfs.xad = &xtPage->xad[XTENTRYSTART];
	} else {
	return NULL;
	}
	return ++jfs.xad;
	}


	static void
	di_read (u32 inum, dinode_t *di)
	{
	s64 key;
	u32 xd, ioffset;
	s64 offset;
	struct xad *xad;
	pxd_t pxd; /* struct size = 8 */

	key = (((inum >> L2INOSPERIAG) << L2INOSPERIAG) + 4096) >> jfs.l2bsize;
	xd = (inum & (INOSPERIAG - 1)) >> L2INOSPEREXT;
	ioffset = ((inum & (INOSPERIAG - 1)) & (INOSPEREXT - 1)) << L2DISIZE;
	xad = first_extent (fileSet);
	do {
	offset = offsetXAD (xad);
	if (isinxt (key, offset, lengthXAD (xad))) {
	devread ((addressXAD (xad) + key - offset) << jfs.bdlog,
	3072 + xdsizeof(pxd_t), sizeof(pxd_t), (unsigned long long)(unsigned int)(char )&pxd, 0xedde0d90);
	devread (addressPXD (&pxd) << jfs.bdlog,
	ioffset, DISIZE, (unsigned long long)(unsigned int)(char *)di, 0xedde0d90);
	break;
	}
	} while ((xad = next_extent ()));
	}

	static ldtentry_t *
	next_dentry (void)
	{
	ldtentry_t *de;
	s8 *stbl;

	if (jfs.dttype == DTTYPE_INLINE) {
	if (jfs.sindex < jfs.slastindex) {
	return (ldtentry_t *)&dtRoot->slot[(int)dtRoot->header.stbl[jfs.sindex++]];
	}
	} else {
	de = (ldtentry_t *)dtPage->slot;
	stbl = (s8 *)&de[(int)dtPage->header.stblindex];
	if (jfs.sindex < jfs.slastindex) {
	return &de[(int)stbl[jfs.sindex++]];
	} else if (dtPage->header.next) {
	devread (dtPage->header.next << jfs.bdlog, 0,
	sizeof(dtpage_t), (unsigned long long)(unsigned int)(char *)dtPage, 0xedde0d90);
	jfs.slastindex = dtPage->header.nextindex;
	jfs.sindex = 1;
	return &de[(int)((s8 *)&de[(int)dtPage->header.stblindex])[0]];
	}
	}

	return (jfs.de_index < 2) ? &de_always[jfs.de_index++] : NULL;
	}

	static ldtentry_t *
	first_dentry (void)
	{
	dtroot_t *dtr;
	pxd_t *xd;
	idtentry_t *de;

	dtr = (dtroot_t *)&iNode->di_xtroot;
	jfs.sindex = 0;
	jfs.de_index = 0;

	de_always[0].inumber = iNode->di_parent;
	de_always[1].inumber = iNode->di_number;
	if (dtr->header.flag & BT_LEAF) {
	jfs.dttype = DTTYPE_INLINE;
	jfs.slastindex = dtr->header.nextindex;
	} else {
	de = (idtentry_t *)dtPage->slot;
	jfs.dttype = DTTYPE_PAGE;
	xd = &((idtentry_t *)dtr->slot)[(int)dtr->header.stbl[0]].xd;
	for (;;) {
	devread (addressPXD (xd) << jfs.bdlog, 0,
	sizeof(dtpage_t), (unsigned long long)(unsigned int)(char *)dtPage, 0xedde0d90);
	if (dtPage->header.flag & BT_LEAF)
	break;
	xd = &de[(int)((s8 *)&de[(int)dtPage->header.stblindex])[0]].xd;
	}
	jfs.slastindex = dtPage->header.nextindex;
	}

	return next_dentry ();
	}


	static dtslot_t *
	next_dslot (int next)
	{
	return (jfs.dttype == DTTYPE_INLINE)
	? (dtslot_t *)&dtRoot->slot[next]
	: &((dtslot_t *)dtPage->slot)[next];
	}

	#if 0
	static void
	uni2ansi (UniChar uni, char ansi, int len)
	{
	for (; len; len--, uni++)
	ansi++ = (uni & 0xff80) ? '?' : (char )uni;
	}
	#else
	#define uni2ansi unicode_to_utf8
	#endif

	int
	jfs_mount (void)
	{
	struct jfs_superblock super; /* struct size = 160 */

	if ((unsigned long)part_length < MINJFS >> SECTOR_BITS
	\|\| !devread (SUPER1_OFF >> SECTOR_BITS, 0,
	sizeof(struct jfs_superblock), (unsigned long long)(unsigned int)(char *)&super, 0xedde0d90)
	\|\| (super.s_magic != JFS_MAGIC)
	\|\| !devread ((AITBL_OFF >> SECTOR_BITS) + FILESYSTEM_I,
	0, DISIZE, (unsigned long long)(unsigned int)(char*)fileSet, 0xedde0d90)) {
	return 0;
	}

	jfs.bsize = super.s_bsize;
	jfs.l2bsize = super.s_l2bsize;
	jfs.bdlog = jfs.l2bsize - SECTOR_BITS;

	return 1;
	}

	unsigned long long
	jfs_read (unsigned long long buf, unsigned long long len, unsigned long write)
	{
	struct xad *xad;
	s64 endofprev, endofcur;
	s64 offset, xadlen;
	unsigned long toread, startpos, endpos;

	startpos = filepos;
	endpos = filepos + len;
	endofprev = (1ULL << 62) - 1;
	xad = first_extent (iNode);
	do {
	offset = offsetXAD (xad);
	xadlen = lengthXAD (xad);
	if (isinxt (filepos >> jfs.l2bsize, offset, xadlen)) {
	endofcur = (offset + xadlen) << jfs.l2bsize;
	toread = (endofcur >= endpos)
	? len : (endofcur - filepos);

	disk_read_func = disk_read_hook;
	devread (addressXAD (xad) << jfs.bdlog,
	filepos - (offset << jfs.l2bsize), toread, buf, write);
	disk_read_func = NULL;

	if (buf)
	buf += toread;
	len -= toread; /* len always >= 0 */
	filepos += toread;
	} else if (offset > endofprev) {
	toread = ((offset << jfs.l2bsize) >= endpos)
	? len : ((offset - endofprev) << jfs.l2bsize);
	filepos += toread;
	#if 0
	{
	unsigned long tmp_pos = toread;
	for (; tmp_pos; tmp_pos--) {
	if (buf)
	*(buf++) = 0;
	}
	}
	#else
	if (buf)
	{
	grub_memset64 (buf, 0, toread);
	buf += toread;
	}
	#endif
	if (len <= toread)
	break;
	len -= toread;
	continue;
	}
	endofprev = offset + xadlen;
	xad = next_extent ();
	} while (len > 0 && xad);

	return filepos - startpos;
	}

	int
	jfs_dir (char *dirname)
	{
	char ptr, rest, ch;
	ldtentry_t *de;
	dtslot_t *ds;
	u32 inum, parent_inum;
	s64 di_size;
	u32 di_mode;
	int cmp;
	unsigned long namlen, n, link_count;
	// char namebuf[JFS_NAME_MAX + 1], linkbuf[JFS_PATH_MAX];

	parent_inum = inum = ROOT_I;
	link_count = 0;
	for (;;) {
	di_read (inum, iNode);
	di_size = iNode->di_size;
	di_mode = iNode->di_mode;

	if ((di_mode & IFMT) == IFLNK) {
	if (++link_count > MAX_LINK_COUNT) {
	errnum = ERR_SYMLINK_LOOP;
	return 0;
	}
	if (di_size < (di_mode & INLINEEA ? 256 : 128)) {
	grub_memmove (linkbuf, iNode->di_fastsymlink, di_size);
	n = di_size;
	} else if (di_size < JFS_PATH_MAX - 1) {
	filepos = 0;
	filemax = di_size;
	n = jfs_read ((unsigned long long)(unsigned int)linkbuf, filemax, 0xedde0d90);
	} else {
	errnum = ERR_FILELENGTH;
	return 0;
	}

	inum = (linkbuf[0] == '/') ? ROOT_I : parent_inum;
	while (n < (JFS_PATH_MAX - 1) && (linkbuf[n++] = *dirname++));
	linkbuf[n] = 0;
	dirname = linkbuf;
	continue;
	}

	if (!dirname \|\| isspace (dirname)) {
	if ((di_mode & IFMT) != IFREG) {
	errnum = ERR_BAD_FILETYPE;
	return 0;
	}
	filepos = 0;
	filemax = di_size;
	return 1;
	}

	if ((di_mode & IFMT) != IFDIR) {
	errnum = ERR_BAD_FILETYPE;
	return 0;
	}

	for (; *dirname == '/'; dirname++);

	//for (rest = dirname; (ch = *rest) && !isspace (ch) && ch != '/'; rest++);
	for (rest = dirname; (ch = *rest) && !isspace (ch) && ch != '/'; rest++)
	{
	if (ch == '\\')
	{
	rest++;
	if (! (ch = *rest))
	break;
	}
	}

	*rest = 0;

	de = first_dentry ();
	for (;;) {
	namlen = de->namlen;
	if (de->next == -1) {
	uni2ansi (de->name, (unsigned char *)namebuf, namlen);
	namebuf[namlen] = 0;
	} else {
	uni2ansi (de->name, (unsigned char *)namebuf, DTLHDRDATALEN);
	ptr = namebuf;
	ptr += DTLHDRDATALEN;
	namlen -= DTLHDRDATALEN;
	ds = next_dslot (de->next);
	while (ds->next != -1) {
	uni2ansi (ds->name, (unsigned char *)ptr, DTSLOTDATALEN);
	ptr += DTSLOTDATALEN;
	namlen -= DTSLOTDATALEN;
	ds = next_dslot (ds->next);
	}
	uni2ansi (ds->name, (unsigned char *)ptr, namlen);
	ptr += namlen;
	*ptr = 0;
	}

	cmp = (!*dirname) ? -1 : substring (dirname, namebuf, 0);
	#ifndef STAGE1_5
	if (print_possibilities && ch != '/'
	&& cmp <= 0) {
	if (print_possibilities > 0)
	print_possibilities = -print_possibilities;
	print_a_completion (namebuf);
	} else
	#endif
	if (cmp == 0) {
	parent_inum = inum;
	inum = de->inumber;
	*(dirname = rest) = ch;
	break;
	}
	de = next_dentry ();
	if (de == NULL) {
	if (print_possibilities < 0)
	return 1;

	errnum = ERR_FILE_NOT_FOUND;
	*rest = ch;
	return 0;
	}
	}
	}
	}

	unsigned long
	jfs_embed (unsigned long *start_sector, unsigned long needed_sectors)
	{
	struct jfs_superblock super; /* struct size = 160 */

	if (needed_sectors > 63
	\|\| !devread (SUPER1_OFF >> SECTOR_BITS, 0,
	sizeof (struct jfs_superblock),
	(unsigned long long)(unsigned int)(char *)&super, 0xedde0d90)
	\|\| (super.s_magic != JFS_MAGIC)) {
	return 0;
	}

	*start_sector = 1;
	return 1;
	}

	#endif /* FSYS_JFS */