Expand PMF_FN_* macros.

[netbsd-mini2440.git] / sys / lib / libsa / ext2fs.c

/*      $NetBSD: ext2fs.c,v 1.7 2009/03/02 10:25:00 tsutsui Exp $       */

/*
 * 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 Ext2 file system.
 */

/* #define EXT2FS_DEBUG */

#include <sys/param.h>
#include <sys/time.h>
#include <ufs/ext2fs/ext2fs_dinode.h>
#include <ufs/ext2fs/ext2fs_dir.h>
#include <ufs/ext2fs/ext2fs.h>
#ifdef _STANDALONE
#include <lib/libkern/libkern.h>
#else
#include <string.h>
#endif

#include "stand.h"
#include "ext2fs.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

#ifndef indp_t
#define indp_t          int32_t
#endif
typedef uint32_t        ino32_t;
#ifndef FSBTODB
#define FSBTODB(fs, indp) 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 m_ext2fs *f_fs;          /* pointer to super-block */
        struct ext2fs_dinode    f_di;           /* copy of on-disk inode */
        uint            f_nishift;      /* for blocks in indirect block */
        indp_t          f_ind_cache_block;
        indp_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 *, indp_t, indp_t *);
static int buf_read_file(struct open_file *, char **, size_t *);
static int search_directory(const char *, int, struct open_file *, ino32_t *);
static int read_sblock(struct open_file *, struct m_ext2fs *);
static int read_gdblock(struct open_file *, struct m_ext2fs *);
#ifdef EXT2FS_DEBUG
static void dump_sblock(struct m_ext2fs *);
#endif

/*
 * 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 m_ext2fs *fs = fp->f_fs;
        char *buf;
        size_t rsize;
        int rc;
        daddr_t inode_sector;
        struct ext2fs_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->e2fs_bsize, buf, &rsize);
        if (rc)
                return rc;
        if (rsize != fs->e2fs_bsize)
                return EIO;

        dip = (struct ext2fs_dinode *)(buf +
            EXT2_DINODE_SIZE(fs) * ino_to_fsbo(fs, inumber));
        e2fs_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 that
 * contains that block.
 */
static int
block_map(struct open_file *f, indp_t file_block, indp_t *disk_block_p)
{
        struct file *fp = (struct file *)f->f_fsdata;
        struct m_ext2fs *fs = fp->f_fs;
        uint level;
        indp_t ind_cache;
        indp_t ind_block_num;
        size_t rsize;
        int rc;
        indp_t *buf = (void *)fp->f_buf;

        /*
         * Index structure of an inode:
         *
         * e2di_blocks[0..NDADDR-1]
         *                      hold block numbers for blocks
         *                      0..NDADDR-1
         *
         * e2di_blocks[NDADDR+0]
         *                      block NDADDR+0 is the single indirect block
         *                      holds block numbers for blocks
         *                      NDADDR .. NDADDR + NINDIR(fs)-1
         *
         * e2di_blocks[NDADDR+1]
         *                      block NDADDR+1 is the double indirect block
         *                      holds block numbers for INDEX blocks for blocks
         *                      NDADDR + NINDIR(fs) ..
         *                      NDADDR + NINDIR(fs) + NINDIR(fs)**2 - 1
         *
         * e2di_blocks[NDADDR+2]
         *                      block NDADDR+2 is the triple indirect block
         *                      holds block numbers for double-indirect
         *                      blocks for blocks
         *                      NDADDR + NINDIR(fs) + NINDIR(fs)**2 ..
         *                      NDADDR + NINDIR(fs) + NINDIR(fs)**2
         *                              + NINDIR(fs)**3 - 1
         */

        if (file_block < NDADDR) {
                /* Direct block. */
                *disk_block_p = fs2h32(fp->f_di.e2di_blocks[file_block]);
                return 0;
        }

        file_block -= NDADDR;

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

        for (level = 0;;) {
                level += fp->f_nishift;
                if (file_block < (indp_t)1 << level)
                        break;
                if (level > NIADDR * fp->f_nishift)
                        /* Block number too high */
                        return EFBIG;
                file_block -= (indp_t)1 << level;
        }

        ind_block_num =
            fs2h32(fp->f_di.e2di_blocks[NDADDR + (level / fp->f_nishift - 1)]);

        for (;;) {
                level -= fp->f_nishift;
                if (ind_block_num == 0) {
                        *disk_block_p = 0;      /* 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(fp->f_fs, ind_block_num), fs->e2fs_bsize,
                        buf, &rsize);
                if (rc)
                        return rc;
                if (rsize != fs->e2fs_bsize)
                        return EIO;
                ind_block_num = fs2h32(buf[file_block >> level]);
                if (level == 0)
                        break;
                file_block &= (1 << level) - 1;
        }

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

        *disk_block_p = ind_block_num;

        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, char **buf_p, size_t *size_p)
{
        struct file *fp = (struct file *)f->f_fsdata;
        struct m_ext2fs *fs = fp->f_fs;
        long off;
        indp_t file_block;
        indp_t disk_block;
        size_t block_size;
        int rc;

        off = blkoff(fs, fp->f_seekp);
        file_block = lblkno(fs, fp->f_seekp);
        block_size = fs->e2fs_bsize;    /* no fragment */

        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.
         */
        /* XXX should handle LARGEFILE */
        if (*size_p > fp->f_di.e2di_size - fp->f_seekp)
                *size_p = fp->f_di.e2di_size - fp->f_seekp;

        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 ext2fs_direct *dp;
        struct ext2fs_direct *edp;
        char *buf;
        size_t buf_size;
        int namlen;
        int rc;

        fp->f_seekp = 0;
        /* XXX should handle LARGEFILE */
        while (fp->f_seekp < (off_t)fp->f_di.e2di_size) {
                rc = buf_read_file(f, &buf, &buf_size);
                if (rc)
                        return rc;

                dp = (struct ext2fs_direct *)buf;
                edp = (struct ext2fs_direct *)(buf + buf_size);
                for (; dp < edp;
                    dp = (void *)((char *)dp + fs2h16(dp->e2d_reclen))) {
                        if (fs2h16(dp->e2d_reclen) <= 0)
                                break;
                        if (fs2h32(dp->e2d_ino) == (ino32_t)0)
                                continue;
                        namlen = dp->e2d_namlen;
                        if (namlen == length &&
                            !memcmp(name, dp->e2d_name, length)) {
                                /* found entry */
                                *inumber_p = fs2h32(dp->e2d_ino);
                                return 0;
                        }
                }
                fp->f_seekp += buf_size;
        }
        return ENOENT;
}

int
read_sblock(struct open_file *f, struct m_ext2fs *fs)
{
        static uint8_t sbbuf[SBSIZE];
        struct ext2fs ext2fs;
        size_t buf_size;
        int rc;

        rc = DEV_STRATEGY(f->f_dev)(f->f_devdata, F_READ,
            SBOFF / DEV_BSIZE, SBSIZE, sbbuf, &buf_size);
        if (rc)
                return rc;

        if (buf_size != SBSIZE)
                return EIO;

        e2fs_sbload((void *)sbbuf, &ext2fs);
        if (ext2fs.e2fs_magic != E2FS_MAGIC)
                return EINVAL;
        if (ext2fs.e2fs_rev > E2FS_REV1 ||
            (ext2fs.e2fs_rev == E2FS_REV1 &&
             (ext2fs.e2fs_first_ino != EXT2_FIRSTINO ||
             (ext2fs.e2fs_inode_size != 128 && ext2fs.e2fs_inode_size != 256) ||
              ext2fs.e2fs_features_incompat & ~EXT2F_INCOMPAT_SUPP))) {
                return ENODEV;
        }

        e2fs_sbload((void *)sbbuf, &fs->e2fs);
        /* compute in-memory m_ext2fs values */
        fs->e2fs_ncg =
            howmany(fs->e2fs.e2fs_bcount - fs->e2fs.e2fs_first_dblock,
            fs->e2fs.e2fs_bpg);
        /* XXX assume hw bsize = 512 */
        fs->e2fs_fsbtodb = fs->e2fs.e2fs_log_bsize + 1;
        fs->e2fs_bsize = MINBSIZE << fs->e2fs.e2fs_log_bsize;
        fs->e2fs_bshift = LOG_MINBSIZE + fs->e2fs.e2fs_log_bsize;
        fs->e2fs_qbmask = fs->e2fs_bsize - 1;
        fs->e2fs_bmask = ~fs->e2fs_qbmask;
        fs->e2fs_ngdb =
            howmany(fs->e2fs_ncg, fs->e2fs_bsize / sizeof(struct ext2_gd));
        fs->e2fs_ipb = fs->e2fs_bsize / ext2fs.e2fs_inode_size;
        fs->e2fs_itpg = fs->e2fs.e2fs_ipg / fs->e2fs_ipb;

        return 0;
}

int
read_gdblock(struct open_file *f, struct m_ext2fs *fs)
{
        struct file *fp = (struct file *)f->f_fsdata;
        size_t rsize;
        uint gdpb;
        int i, rc;

        gdpb = fs->e2fs_bsize / sizeof(struct ext2_gd);

        for (i = 0; i < fs->e2fs_ngdb; i++) {
                rc = DEV_STRATEGY(f->f_dev)(f->f_devdata, F_READ,
                    FSBTODB(fs, fs->e2fs.e2fs_first_dblock +
                    1 /* superblock */ + i),
                    fs->e2fs_bsize, fp->f_buf, &rsize);
                if (rc)
                        return rc;
                if (rsize != fs->e2fs_bsize)
                        return EIO;

                e2fs_cgload((struct ext2_gd *)fp->f_buf,
                    &fs->e2fs_gd[i * gdpb],
                    (i == (fs->e2fs_ngdb - 1)) ?
                    (fs->e2fs_ncg - gdpb * i) * sizeof(struct ext2_gd):
                    fs->e2fs_bsize);
        }

        return 0;
}


/*
 * Open a file.
 */
int
ext2fs_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 m_ext2fs *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));
        fp->f_fs = fs;
        twiddle();

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

#ifdef EXT2FS_DEBUG
        dump_sblock(fs);
#endif

        /* alloc a block sized buffer used for all fs transfers */
        fp->f_buf = alloc(fs->e2fs_bsize);

        /* read group descriptor blocks */
        fs->e2fs_gd = alloc(sizeof(struct ext2_gd) * fs->e2fs_ncg);
        rc = read_gdblock(f, fs);
        if (rc)
                goto out;

        /*
         * Calculate indirect block levels.
         */
        {
                indp_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 avoinds pulling in the
                 * 64bit division routine into the boot code.
                 */
                mult = 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 = EXT2_ROOTINO;
        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.e2di_mode & EXT2_IFMT) != EXT2_IFDIR) {
                        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.e2di_mode & EXT2_IFMT) == EXT2_IFLNK) {
                        /* XXX should handle LARGEFILE */
                        int link_len = fp->f_di.e2di_size;
                        int len;

                        len = strlen(cp);

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

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

                        if (link_len < EXT2_MAXSYMLINKLEN) {
                                memcpy(namebuf, fp->f_di.e2di_blocks, link_len);
                        } else {
                                /*
                                 * Read file for symbolic link
                                 */
                                size_t buf_size;
                                indp_t  disk_block;

                                buf = fp->f_buf;
                                rc = block_map(f, (indp_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->e2fs_bsize, 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)EXT2_ROOTINO;

                        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)
                ext2fs_close(f);
        else {
                fsmod = "ext2fs";
                fsmod2 = "ffs";
        }
        return rc;
}

int
ext2fs_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_fs->e2fs_gd)
                dealloc(fp->f_fs->e2fs_gd,
                    sizeof(struct ext2_gd) * fp->f_fs->e2fs_ncg);
        if (fp->f_buf)
                dealloc(fp->f_buf, fp->f_fs->e2fs_bsize);
        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.
 */
int
ext2fs_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) {
                /* XXX should handle LARGEFILE */
                if (fp->f_seekp >= (off_t)fp->f_di.e2di_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
int
ext2fs_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
off_t
ext2fs_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:
                /* XXX should handle LARGEFILE */
                fp->f_seekp = fp->f_di.e2di_size - offset;
                break;
        default:
                return -1;
        }
        return fp->f_seekp;
}
#endif /* !LIBSA_NO_FS_SEEK */

int
ext2fs_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.e2di_mode;
        sb->st_uid = fp->f_di.e2di_uid;
        sb->st_gid = fp->f_di.e2di_gid;
        /* XXX should handle LARGEFILE */
        sb->st_size = fp->f_di.e2di_size;
        return 0;
}

/*
 * byte swap functions for big endian machines
 * (ext2fs is always little endian)
 *
 * XXX: We should use src/sys/ufs/ext2fs/ext2fs_bswap.c
 */

/* These functions are only needed if native byte order is not big endian */
#if BYTE_ORDER == BIG_ENDIAN
void
e2fs_sb_bswap(struct ext2fs *old, struct ext2fs *new)
{

        /* preserve unused fields */
        memcpy(new, old, sizeof(struct ext2fs));
        new->e2fs_icount        =       bswap32(old->e2fs_icount);
        new->e2fs_bcount        =       bswap32(old->e2fs_bcount);
        new->e2fs_rbcount       =       bswap32(old->e2fs_rbcount);
        new->e2fs_fbcount       =       bswap32(old->e2fs_fbcount);
        new->e2fs_ficount       =       bswap32(old->e2fs_ficount);
        new->e2fs_first_dblock  =       bswap32(old->e2fs_first_dblock);
        new->e2fs_log_bsize     =       bswap32(old->e2fs_log_bsize);
        new->e2fs_fsize         =       bswap32(old->e2fs_fsize);
        new->e2fs_bpg           =       bswap32(old->e2fs_bpg);
        new->e2fs_fpg           =       bswap32(old->e2fs_fpg);
        new->e2fs_ipg           =       bswap32(old->e2fs_ipg);
        new->e2fs_mtime         =       bswap32(old->e2fs_mtime);
        new->e2fs_wtime         =       bswap32(old->e2fs_wtime);
        new->e2fs_mnt_count     =       bswap16(old->e2fs_mnt_count);
        new->e2fs_max_mnt_count =       bswap16(old->e2fs_max_mnt_count);
        new->e2fs_magic         =       bswap16(old->e2fs_magic);
        new->e2fs_state         =       bswap16(old->e2fs_state);
        new->e2fs_beh           =       bswap16(old->e2fs_beh);
        new->e2fs_minrev        =       bswap16(old->e2fs_minrev);
        new->e2fs_lastfsck      =       bswap32(old->e2fs_lastfsck);
        new->e2fs_fsckintv      =       bswap32(old->e2fs_fsckintv);
        new->e2fs_creator       =       bswap32(old->e2fs_creator);
        new->e2fs_rev           =       bswap32(old->e2fs_rev);
        new->e2fs_ruid          =       bswap16(old->e2fs_ruid);
        new->e2fs_rgid          =       bswap16(old->e2fs_rgid);
        new->e2fs_first_ino     =       bswap32(old->e2fs_first_ino);
        new->e2fs_inode_size    =       bswap16(old->e2fs_inode_size);
        new->e2fs_block_group_nr =      bswap16(old->e2fs_block_group_nr);
        new->e2fs_features_compat =     bswap32(old->e2fs_features_compat);
        new->e2fs_features_incompat =   bswap32(old->e2fs_features_incompat);
        new->e2fs_features_rocompat =   bswap32(old->e2fs_features_rocompat);
        new->e2fs_algo          =       bswap32(old->e2fs_algo);
        new->e2fs_reserved_ngdb =       bswap16(old->e2fs_reserved_ngdb);
}

void e2fs_cg_bswap(struct ext2_gd *old, struct ext2_gd *new, int size)
{
        int i;

        for (i = 0; i < (size / sizeof(struct ext2_gd)); i++) {
                new[i].ext2bgd_b_bitmap = bswap32(old[i].ext2bgd_b_bitmap);
                new[i].ext2bgd_i_bitmap = bswap32(old[i].ext2bgd_i_bitmap);
                new[i].ext2bgd_i_tables = bswap32(old[i].ext2bgd_i_tables);
                new[i].ext2bgd_nbfree   = bswap16(old[i].ext2bgd_nbfree);
                new[i].ext2bgd_nifree   = bswap16(old[i].ext2bgd_nifree);
                new[i].ext2bgd_ndirs    = bswap16(old[i].ext2bgd_ndirs);
        }
}

void e2fs_i_bswap(struct ext2fs_dinode *old, struct ext2fs_dinode *new)
{

        new->e2di_mode          =       bswap16(old->e2di_mode);
        new->e2di_uid           =       bswap16(old->e2di_uid);
        new->e2di_gid           =       bswap16(old->e2di_gid);
        new->e2di_nlink         =       bswap16(old->e2di_nlink);
        new->e2di_size          =       bswap32(old->e2di_size);
        new->e2di_atime         =       bswap32(old->e2di_atime);
        new->e2di_ctime         =       bswap32(old->e2di_ctime);
        new->e2di_mtime         =       bswap32(old->e2di_mtime);
        new->e2di_dtime         =       bswap32(old->e2di_dtime);
        new->e2di_nblock        =       bswap32(old->e2di_nblock);
        new->e2di_flags         =       bswap32(old->e2di_flags);
        new->e2di_gen           =       bswap32(old->e2di_gen);
        new->e2di_facl          =       bswap32(old->e2di_facl);
        new->e2di_dacl          =       bswap32(old->e2di_dacl);
        new->e2di_faddr         =       bswap32(old->e2di_faddr);
        memcpy(&new->e2di_blocks[0], &old->e2di_blocks[0],
            (NDADDR + NIADDR) * sizeof(uint32_t));
}
#endif

#ifdef EXT2FS_DEBUG
void
dump_sblock(struct m_ext2fs *fs)
{

        printf("fs->e2fs.e2fs_bcount = %u\n", fs->e2fs.e2fs_bcount);
        printf("fs->e2fs.e2fs_first_dblock = %u\n", fs->e2fs.e2fs_first_dblock);
        printf("fs->e2fs.e2fs_log_bsize = %u\n", fs->e2fs.e2fs_log_bsize);
        printf("fs->e2fs.e2fs_bpg = %u\n", fs->e2fs.e2fs_bpg);
        printf("fs->e2fs.e2fs_ipg = %u\n", fs->e2fs.e2fs_ipg);
        printf("fs->e2fs.e2fs_magic = 0x%x\n", fs->e2fs.e2fs_magic);
        printf("fs->e2fs.e2fs_rev = %u\n", fs->e2fs.e2fs_rev);

        if (fs->e2fs.e2fs_rev == E2FS_REV1) {
                printf("fs->e2fs.e2fs_first_ino = %u\n",
                    fs->e2fs.e2fs_first_ino);
                printf("fs->e2fs.e2fs_inode_size = %u\n",
                    fs->e2fs.e2fs_inode_size);
                printf("fs->e2fs.e2fs_features_compat = %u\n",
                    fs->e2fs.e2fs_features_compat);
                printf("fs->e2fs.e2fs_features_incompat = %u\n",
                    fs->e2fs.e2fs_features_incompat);
                printf("fs->e2fs.e2fs_features_rocompat = %u\n",
                    fs->e2fs.e2fs_features_rocompat);
                printf("fs->e2fs.e2fs_reserved_ngdb = %u\n",
                    fs->e2fs.e2fs_reserved_ngdb);
        }

        printf("fs->e2fs_bsize = %u\n", fs->e2fs_bsize);
        printf("fs->e2fs_fsbtodb = %u\n", fs->e2fs_fsbtodb);
        printf("fs->e2fs_ncg = %u\n", fs->e2fs_ncg);
        printf("fs->e2fs_ngdb = %u\n", fs->e2fs_ngdb);
        printf("fs->e2fs_ipb = %u\n", fs->e2fs_ipb);
        printf("fs->e2fs_itpg = %u\n", fs->e2fs_itpg);
}
#endif