/*      $NetBSD: minixfs3.c,v 1.14 2025/12/19 09:31:16 nia Exp $        */

/*-
 * Copyright (c) 2012
 *      Vrije Universiteit, Amsterdam, The Netherlands. All rights reserved.
 *
 * Author: Evgeniy Ivanov (based on libsa/ext2fs.c).
 *
 * This code is derived from src/sys/lib/libsa/ext2fs.c contributed to 
 * The NetBSD Foundation, see copyrights below.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS
 * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Copyright (c) 1997 Manuel Bouyer.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*-
 * Copyright (c) 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * The Mach Operating System project at Carnegie-Mellon University.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *
 * Copyright (c) 1990, 1991 Carnegie Mellon University
 * All Rights Reserved.
 *
 * Author: David Golub
 *
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 *
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie the
 * rights to redistribute these changes.
 */

/*
 *      Stand-alone file reading package for MFS file system.
 */

#include <sys/param.h>
#include <sys/endian.h>
#include <sys/time.h>
#ifdef _STANDALONE
#include <lib/libkern/libkern.h>
#else
#include <stddef.h>
#include <string.h>
#endif

#include "stand.h"
#include "minixfs3.h"

#if defined(LIBSA_FS_SINGLECOMPONENT) && !defined(LIBSA_NO_FS_SYMLINK)
#define LIBSA_NO_FS_SYMLINK
#endif

#if defined(LIBSA_NO_TWIDDLE)
#define twiddle()
#endif

typedef uint32_t        ino32_t;
#ifndef FSBTODB
#define FSBTODB(fs, indp) MFS_FSBTODB(fs, indp)
#endif

/*
 * To avoid having a lot of filesystem-block sized buffers lurking (which
 * could be 32k) we only keep a few entries of the indirect block map.
 * With 8k blocks, 2^8 blocks is ~500k so we reread the indirect block
 * ~13 times pulling in a 6M kernel.
 * The cache size must be smaller than the smallest filesystem block,
 * so LN2_IND_CACHE_SZ <= 9 (UFS2 and 4k blocks).
 */
#define LN2_IND_CACHE_SZ        6
#define IND_CACHE_SZ            (1 << LN2_IND_CACHE_SZ)
#define IND_CACHE_MASK          (IND_CACHE_SZ - 1)

/*
 * In-core open file.
 */
struct file {
        off_t           f_seekp;        /* seek pointer */
        struct mfs_sblock  *f_fs;       /* pointer to super-block */
        struct mfs_dinode  f_di;        /* copy of on-disk inode */
        uint            f_nishift;      /* for blocks in indirect block */
        block_t         f_ind_cache_block;
        block_t         f_ind_cache[IND_CACHE_SZ];

        char            *f_buf;         /* buffer for data block */
        size_t          f_buf_size;     /* size of data block */
        daddr_t         f_buf_blkno;    /* block number of data block */
};

static int read_inode(ino32_t, struct open_file *);
static int block_map(struct open_file *, block_t, block_t *);
static int buf_read_file(struct open_file *, void *, size_t *);
static int search_directory(const char *, int, struct open_file *, ino32_t *);
static int read_sblock(struct open_file *, struct mfs_sblock *);

/*
 * Read a new inode into a file structure.
 */
static int
read_inode(ino32_t inumber, struct open_file *f)
{
        struct file *fp = (struct file *)f->f_fsdata;
        struct mfs_sblock *fs = fp->f_fs;
        char *buf;
        size_t rsize;
        int rc;
        daddr_t inode_sector;
        struct mfs_dinode *dip;

        inode_sector = FSBTODB(fs, ino_to_fsba(fs, inumber));

        /*
         * Read inode and save it.
         */
        buf = fp->f_buf;
        twiddle();
        rc = DEV_STRATEGY(f->f_dev)(f->f_devdata, F_READ,
            inode_sector, fs->mfs_block_size, buf, &rsize);
        if (rc)
                return rc;
        if (rsize != fs->mfs_block_size)
                return EIO;

        dip = (struct mfs_dinode *)(buf +
            INODE_SIZE * ino_to_fsbo(fs, inumber));
        mfs_iload(dip, &fp->f_di);

        /*
         * Clear out the old buffers
         */
        fp->f_ind_cache_block = ~0;
        fp->f_buf_blkno = -1;
        return rc;
}

/*
 * Given an offset in a file, find the disk block number (not zone!)
 * that contains that block.
 */
static int
block_map(struct open_file *f, block_t file_block, block_t *disk_block_p)
{
        struct file *fp = (struct file *)f->f_fsdata;
        struct mfs_sblock *fs = fp->f_fs;
        uint level;
        block_t ind_cache;
        block_t ind_block_num;
        zone_t zone;
        size_t rsize;
        int rc;
        int boff;
        int scale = fs->mfs_log_zone_size; /* for block-zone conversion */
        block_t *buf = (void *)fp->f_buf;

        /*
         * Index structure of an inode:
         *
         * mdi_blocks[0..NR_DZONES-1]
         *                      hold zone numbers for zones
         *                      0..NR_DZONES-1
         *
         * mdi_blocks[NR_DZONES+0]
         *                      block NDADDR+0 is the single indirect block
         *                      holds zone numbers for zones
         *                      NR_DZONES .. NR_DZONES + MFS_NINDIR(fs)-1
         *
         * mdi_blocks[NR_DZONES+1]
         *                      block NDADDR+1 is the double indirect block
         *                      holds zone numbers for INDEX blocks for zones
         *                      NR_DZONES + MFS_NINDIR(fs) ..
         *                      NR_TZONES + MFS_NINDIR(fs) + MFS_NINDIR(fs)**2 - 1
         */

        zone = file_block >> scale;
        boff = (int) (file_block - (zone << scale) ); /* relative blk in zone */

        if (zone < NR_DZONES) {
                /* Direct zone */
                zone_t z = fs2h32(fp->f_di.mdi_zone[zone]);
                if (z == NO_ZONE) {
                        *disk_block_p = NO_BLOCK;
                        return 0;
                }
                *disk_block_p = (block_t) ((z << scale) + boff);
                return 0;
        }

        zone -= NR_DZONES;

        ind_cache = zone >> LN2_IND_CACHE_SZ;
        if (ind_cache == fp->f_ind_cache_block) {
                *disk_block_p =
                    fs2h32(fp->f_ind_cache[zone & IND_CACHE_MASK]);
                return 0;
        }

        for (level = 0;;) {
                level += fp->f_nishift;

                if (zone < (block_t)1 << level)
                        break;
                if (level > NIADDR * fp->f_nishift)
                        /* Zone number too high */
                        return EFBIG;
                zone -= (block_t)1 << level;
        }

        ind_block_num =
            fs2h32(fp->f_di.mdi_zone[NR_DZONES + (level / fp->f_nishift - 1)]);

        for (;;) {
                level -= fp->f_nishift;
                if (ind_block_num == 0) {
                        *disk_block_p = NO_BLOCK;       /* missing */
                        return 0;
                }

                twiddle();
                /*
                 * If we were feeling brave, we could work out the number
                 * of the disk sector and read a single disk sector instead
                 * of a filesystem block.
                 * However we don't do this very often anyway...
                 */
                rc = DEV_STRATEGY(f->f_dev)(f->f_devdata, F_READ,
                        FSBTODB(fs, ind_block_num), fs->mfs_block_size,
                        buf, &rsize);
                if (rc)
                        return rc;
                if (rsize != fs->mfs_block_size)
                        return EIO;

                ind_block_num = fs2h32(buf[zone >> level]);
                if (level == 0)
                        break;
                zone &= (1 << level) - 1;
        }

        /* Save the part of the block that contains this sector */
        memcpy(fp->f_ind_cache, &buf[zone & ~IND_CACHE_MASK],
            IND_CACHE_SZ * sizeof fp->f_ind_cache[0]);
        fp->f_ind_cache_block = ind_cache;

        zone = (zone_t)ind_block_num;
        *disk_block_p = (block_t)((zone << scale) + boff);
        return 0;
}

/*
 * Read a portion of a file into an internal buffer.
 * Return the location in the buffer and the amount in the buffer.
 */
static int
buf_read_file(struct open_file *f, void *v, size_t *size_p)
{
        char **buf_p = v;
        struct file *fp = (struct file *)f->f_fsdata;
        struct mfs_sblock *fs = fp->f_fs;
        long off;
        block_t file_block;
        block_t disk_block = 0; /* XXX: gcc */
        size_t block_size, nsz;
        int rc;

        off = mfs_blkoff(fs, fp->f_seekp);
        file_block = mfs_lblkno(fs, fp->f_seekp);
        block_size = fs->mfs_block_size;

        if (file_block != fp->f_buf_blkno) {
                rc = block_map(f, file_block, &disk_block);
                if (rc)
                        return rc;

                if (disk_block == 0) {
                        memset(fp->f_buf, 0, block_size);
                        fp->f_buf_size = block_size;
                } else {
                        twiddle();
                        rc = DEV_STRATEGY(f->f_dev)(f->f_devdata, F_READ,
                                FSBTODB(fs, disk_block),
                                block_size, fp->f_buf, &fp->f_buf_size);
                        if (rc)
                                return rc;
                }

                fp->f_buf_blkno = file_block;
        }

        /*
         * Return address of byte in buffer corresponding to
         * offset, and size of remainder of buffer after that
         * byte.
         */
        *buf_p = fp->f_buf + off;
        *size_p = block_size - off;

        /*
         * But truncate buffer at end of file.
         */
        nsz = (size_t)(fp->f_di.mdi_size - fp->f_seekp);
        if (*size_p > nsz)
                *size_p = nsz;

        return 0;
}

/*
 * Search a directory for a name and return its
 * inode number.
 */
static int
search_directory(const char *name, int length, struct open_file *f,
        ino32_t *inumber_p)
{
        struct file *fp = (struct file *)f->f_fsdata;
        struct mfs_sblock *fs = fp->f_fs;
        struct mfs_direct *dp;
        struct mfs_direct *dbuf;
        size_t buf_size;
        int namlen;
        int rc;

        fp->f_seekp = 0;

        while (fp->f_seekp < (off_t)fp->f_di.mdi_size) {
                rc = buf_read_file(f, (void *)&dbuf, &buf_size);
                if (rc)
                        return rc;
                if (buf_size == 0)
                        return EIO;

                /* XXX we assume, that buf_read_file reads an fs block and
                 * doesn't truncate buffer. Currently i_size in MFS doesn't
                 * the same as size of allocated blocks, it makes buf_read_file
                 * to truncate buf_size.
                 */
                if (buf_size < fs->mfs_block_size)
                        buf_size = fs->mfs_block_size;

                for (dp = dbuf; dp < &dbuf[NR_DIR_ENTRIES(fs)]; dp++) {
                        char *cp;
                        if (fs2h32(dp->mfsd_ino) == (ino32_t) 0)
                                continue;
                        /* Compute the length of the name */
                        cp = memchr(dp->mfsd_name, '\0', sizeof(dp->mfsd_name));
                        if (cp == NULL)
                                namlen = sizeof(dp->mfsd_name);
                        else
                                namlen = cp - (dp->mfsd_name);

                        if (namlen == length &&
                            !memcmp(name, dp->mfsd_name, length)) {
                                /* found entry */
                                *inumber_p = fs2h32(dp->mfsd_ino);
                                return 0;
                        }
                }
                fp->f_seekp += buf_size;
        }
        return ENOENT;
}

int
read_sblock(struct open_file *f, struct mfs_sblock *fs)
{
        static uint8_t sbbuf[MINBSIZE];
        size_t buf_size;
        int rc;

        /* We must read amount multiple of sector size, hence we can't
         * read SBSIZE and read MINBSIZE.
         */
        if (SBSIZE > MINBSIZE)
                return EINVAL;

        rc = DEV_STRATEGY(f->f_dev)(f->f_devdata, F_READ,
            SUPER_BLOCK_OFF / GETSECSIZE(f), MINBSIZE, sbbuf, &buf_size);
        if (rc)
                return rc;

        if (buf_size != MINBSIZE)
                return EIO;

        mfs_sbload((void *)sbbuf, fs);

        if (fs->mfs_magic != SUPER_MAGIC)
                return EINVAL;
        if (fs->mfs_block_size < MINBSIZE)
                return EINVAL;
        if ((fs->mfs_block_size % 512) != 0)
                return EINVAL;
        if (SBSIZE > fs->mfs_block_size)
                return EINVAL;
        if ((fs->mfs_block_size % INODE_SIZE) != 0)
                return EINVAL;

        /* For even larger disks, a similar problem occurs with s_firstdatazone.
         * If the on-disk field contains zero, we assume that the value was too
         * large to fit, and compute it on the fly.
         */
        if (fs->mfs_firstdatazone_old == 0) {
                block_t offset;
                offset = START_BLOCK + fs->mfs_imap_blocks + fs->mfs_zmap_blocks;
                offset += (fs->mfs_ninodes + fs->mfs_inodes_per_block - 1) /
                                fs->mfs_inodes_per_block;

                fs->mfs_firstdatazone =
                        (offset + (1 << fs->mfs_log_zone_size) - 1) >>
                                fs->mfs_log_zone_size;
        } else {
                fs->mfs_firstdatazone = (zone_t) fs->mfs_firstdatazone_old;
        }

        if (fs->mfs_imap_blocks < 1 || fs->mfs_zmap_blocks < 1
                        || fs->mfs_ninodes < 1 || fs->mfs_zones < 1
                        || fs->mfs_firstdatazone <= 4
                        || fs->mfs_firstdatazone >= fs->mfs_zones
                        || (unsigned) fs->mfs_log_zone_size > 4)
                return EINVAL;

        /* compute in-memory mfs_sblock values */
        fs->mfs_inodes_per_block = fs->mfs_block_size / INODE_SIZE;


        {
                int32_t mult = fs->mfs_block_size >> LOG_MINBSIZE;
                int ln2 = LOG_MINBSIZE;

                for (; mult != 1; ln2++)
                        mult >>= 1;

                fs->mfs_bshift = ln2;
                /* XXX assume hw bsize = 512 */
                fs->mfs_fsbtodb = ln2 - LOG_MINBSIZE + 1;
        }

        fs->mfs_qbmask = fs->mfs_block_size - 1;
        fs->mfs_bmask = ~fs->mfs_qbmask;

        return 0;
}

/*
 * Open a file.
 */
__compactcall int
minixfs3_open(const char *path, struct open_file *f)
{
#ifndef LIBSA_FS_SINGLECOMPONENT
        const char *cp, *ncp;
        int c;
#endif
        ino32_t inumber;
        struct file *fp;
        struct mfs_sblock *fs;
        int rc;
#ifndef LIBSA_NO_FS_SYMLINK
        ino32_t parent_inumber;
        int nlinks = 0;
        char namebuf[MAXPATHLEN+1];
        char *buf;
#endif

        /* allocate file system specific data structure */
        fp = alloc(sizeof(struct file));
        memset(fp, 0, sizeof(struct file));
        f->f_fsdata = (void *)fp;

        /* allocate space and read super block */
        fs = alloc(sizeof(*fs));
        memset(fs, 0, sizeof(*fs));
        fp->f_fs = fs;
        twiddle();

        rc = read_sblock(f, fs);
        if (rc)
                goto out;

        /* alloc a block sized buffer used for all fs transfers */
        fp->f_buf = alloc(fs->mfs_block_size);

        /*
         * Calculate indirect block levels.
         */
        {
                int32_t mult;
                int ln2;

                /*
                 * We note that the number of indirect blocks is always
                 * a power of 2.  This lets us use shifts and masks instead
                 * of divide and remainder and avoids pulling in the
                 * 64bit division routine into the boot code.
                 */
                mult = MFS_NINDIR(fs);
#ifdef DEBUG
                if (!powerof2(mult)) {
                        /* Hummm was't a power of 2 */
                        rc = EINVAL;
                        goto out;
                }
#endif
                for (ln2 = 0; mult != 1; ln2++)
                        mult >>= 1;

                fp->f_nishift = ln2;
        }

        inumber = ROOT_INODE;
        if ((rc = read_inode(inumber, f)) != 0)
                goto out;

#ifndef LIBSA_FS_SINGLECOMPONENT
        cp = path;
        while (*cp) {

                /*
                 * Remove extra separators
                 */
                while (*cp == '/')
                        cp++;
                if (*cp == '\0')
                        break;

                /*
                 * Check that current node is a directory.
                 */
                if ((fp->f_di.mdi_mode & I_TYPE) != I_DIRECTORY) {
                        rc = ENOTDIR;
                        goto out;
                }

                /*
                 * Get next component of path name.
                 */
                ncp = cp;
                while ((c = *cp) != '\0' && c != '/')
                        cp++;

                /*
                 * Look up component in current directory.
                 * Save directory inumber in case we find a
                 * symbolic link.
                 */
#ifndef LIBSA_NO_FS_SYMLINK
                parent_inumber = inumber;
#endif
                rc = search_directory(ncp, cp - ncp, f, &inumber);
                if (rc)
                        goto out;

                /*
                 * Open next component.
                 */
                if ((rc = read_inode(inumber, f)) != 0)
                        goto out;

#ifndef LIBSA_NO_FS_SYMLINK
                /*
                 * Check for symbolic link.
                 */
                if ((fp->f_di.mdi_mode & I_TYPE) == I_SYMBOLIC_LINK) {
                        int link_len = fp->f_di.mdi_size;
                        int len;
                        size_t buf_size;
                        block_t disk_block;

                        len = strlen(cp);

                        if (link_len + len > MAXPATHLEN ||
                            ++nlinks > MAXSYMLINKS) {
                                rc = ENOENT;
                                goto out;
                        }

                        memmove(&namebuf[link_len], cp, len + 1);

                        /*
                         * Read file for symbolic link
                         */
                        buf = fp->f_buf;
                        rc = block_map(f, (block_t)0, &disk_block);
                        if (rc)
                                goto out;

                        twiddle();
                        rc = DEV_STRATEGY(f->f_dev)(f->f_devdata,
                                        F_READ, FSBTODB(fs, disk_block),
                                        fs->mfs_block_size, buf, &buf_size);
                        if (rc)
                                goto out;

                        memcpy(namebuf, buf, link_len);

                        /*
                         * If relative pathname, restart at parent directory.
                         * If absolute pathname, restart at root.
                         */
                        cp = namebuf;
                        if (*cp != '/')
                                inumber = parent_inumber;
                        else
                                inumber = (ino32_t) ROOT_INODE;

                        if ((rc = read_inode(inumber, f)) != 0)
                                goto out;
                }
#endif  /* !LIBSA_NO_FS_SYMLINK */
        }

        /*
         * Found terminal component.
         */
        rc = 0;

#else /* !LIBSA_FS_SINGLECOMPONENT */

        /* look up component in the current (root) directory */
        rc = search_directory(path, strlen(path), f, &inumber);
        if (rc)
                goto out;

        /* open it */
        rc = read_inode(inumber, f);

#endif /* !LIBSA_FS_SINGLECOMPONENT */

        fp->f_seekp = 0;                /* reset seek pointer */

out:
        if (rc)
                minixfs3_close(f);

        return rc;
}

__compactcall int
minixfs3_close(struct open_file *f)
{
        struct file *fp = (struct file *)f->f_fsdata;

        f->f_fsdata = NULL;
        if (fp == NULL)
                return 0;

        if (fp->f_buf)
                dealloc(fp->f_buf, fp->f_fs->mfs_block_size);
        dealloc(fp->f_fs, sizeof(*fp->f_fs));
        dealloc(fp, sizeof(struct file));
        return 0;
}

/*
 * Copy a portion of a file into kernel memory.
 * Cross block boundaries when necessary.
 */
__compactcall int
minixfs3_read(struct open_file *f, void *start, size_t size, size_t *resid)
{
        struct file *fp = (struct file *)f->f_fsdata;
        size_t csize;
        char *buf;
        size_t buf_size;
        int rc = 0;
        char *addr = start;

        while (size != 0) {
                if (fp->f_seekp >= (off_t)fp->f_di.mdi_size)
                        break;

                rc = buf_read_file(f, &buf, &buf_size);
                if (rc)
                        break;

                csize = size;
                if (csize > buf_size)
                        csize = buf_size;

                memcpy(addr, buf, csize);

                fp->f_seekp += csize;
                addr += csize;
                size -= csize;
        }

        if (resid)
                *resid = size;
        return rc;
}

/*
 * Not implemented.
 */
#ifndef LIBSA_NO_FS_WRITE
__compactcall int
minixfs3_write(struct open_file *f, void *start, size_t size, size_t *resid)
{

        return EROFS;
}
#endif /* !LIBSA_NO_FS_WRITE */

#ifndef LIBSA_NO_FS_SEEK
__compactcall off_t
minixfs3_seek(struct open_file *f, off_t offset, int where)
{
        struct file *fp = (struct file *)f->f_fsdata;

        switch (where) {
        case SEEK_SET:
                fp->f_seekp = offset;
                break;
        case SEEK_CUR:
                fp->f_seekp += offset;
                break;
        case SEEK_END:
                fp->f_seekp = fp->f_di.mdi_size - offset;
                break;
        default:
                return -1;
        }
        return fp->f_seekp;
}
#endif /* !LIBSA_NO_FS_SEEK */

__compactcall int
minixfs3_stat(struct open_file *f, struct stat *sb)
{
        struct file *fp = (struct file *)f->f_fsdata;

        /* only important stuff */
        memset(sb, 0, sizeof *sb);
        sb->st_mode = fp->f_di.mdi_mode;
        sb->st_uid = fp->f_di.mdi_uid;
        sb->st_gid = fp->f_di.mdi_gid;
        sb->st_size = fp->f_di.mdi_size;
        return 0;
}

#if defined(LIBSA_ENABLE_LS_OP)
#include "ls.h"
__compactcall void
minixfs3_ls(struct open_file *f, const char *pattern)
{
        struct file *fp = (struct file *)f->f_fsdata;
        struct mfs_sblock *fs = fp->f_fs;
        struct mfs_direct *dp;
        struct mfs_direct *dbuf;
        size_t buf_size;
        lsentry_t *names = 0;

        fp->f_seekp = 0;
        while (fp->f_seekp < (off_t)fp->f_di.mdi_size) {
                int rc = buf_read_file(f, &dbuf, &buf_size);
                if (rc)
                        goto out;

                /* XXX we assume, that buf_read_file reads an fs block and
                 * doesn't truncate buffer. Currently i_size in MFS doesn't
                 * the same as size of allocated blocks, it makes buf_read_file
                 * to truncate buf_size.
                 */
                if (buf_size < fs->mfs_block_size)
                        buf_size = fs->mfs_block_size;

                for (dp = dbuf; dp < &dbuf[NR_DIR_ENTRIES(fs)]; dp++) {
                        char *cp;
                        int namlen;

                        if (fs2h32(dp->mfsd_ino) == 0)
                                continue;

                        /* Compute the length of the name,
                         * We don't use strlen and strcpy, because original MFS
                         * code doesn't.
                         */
                        cp = memchr(dp->mfsd_name, '\0', sizeof(dp->mfsd_name));
                        if (cp == NULL)
                                namlen = sizeof(dp->mfsd_name);
                        else
                                namlen = cp - (dp->mfsd_name);

                        lsadd(&names, pattern, dp->mfsd_name, namlen, 
                            fs2h32(dp->mfsd_ino), "?");
                }
                fp->f_seekp += buf_size;
        }
        lsprint(names);
out:    lsfree(names);
}
#endif

/*
 * byte swap functions for big endian machines
 * (mfs is always little endian)
 */

/* These functions are only needed if native byte order is not big endian */
#if BYTE_ORDER == BIG_ENDIAN
void
minixfs3_sb_bswap(struct mfs_sblock *old, struct mfs_sblock *new)
{
        new->mfs_ninodes        =       bswap32(old->mfs_ninodes);
        new->mfs_nzones         =       bswap16(old->mfs_nzones);
        new->mfs_imap_blocks    =       bswap16(old->mfs_imap_blocks);
        new->mfs_zmap_blocks    =       bswap16(old->mfs_zmap_blocks);
        new->mfs_firstdatazone_old =    bswap16(old->mfs_firstdatazone_old);
        new->mfs_log_zone_size  =       bswap16(old->mfs_log_zone_size);
        new->mfs_max_size       =       bswap32(old->mfs_max_size);
        new->mfs_zones          =       bswap32(old->mfs_zones);
        new->mfs_magic          =       bswap16(old->mfs_magic);
        new->mfs_block_size     =       bswap16(old->mfs_block_size);
        new->mfs_disk_version   =       old->mfs_disk_version;
}

void minixfs3_i_bswap(struct mfs_dinode *old, struct mfs_dinode *new)
{
        int i;

        new->mdi_mode           =       bswap16(old->mdi_mode);
        new->mdi_nlinks         =       bswap16(old->mdi_nlinks);
        new->mdi_uid            =       bswap16(old->mdi_uid);
        new->mdi_gid            =       bswap16(old->mdi_gid);
        new->mdi_size           =       bswap32(old->mdi_size);
        new->mdi_atime          =       bswap32(old->mdi_atime);
        new->mdi_mtime          =       bswap32(old->mdi_mtime);
        new->mdi_ctime          =       bswap32(old->mdi_ctime);

        /* We don't swap here, because indirects must be swapped later
         * anyway, hence everything is done by block_map().
         */
        for (i = 0; i < NR_TZONES; i++)
                new->mdi_zone[i] = old->mdi_zone[i];
}
#endif