/* $FreeBSD: src/lib/libstand/ufs.c,v 1.5.6.1 2000/05/04 13:47:53 ps Exp $ */
/*      $NetBSD: ufs.c,v 1.20 1998/03/01 07:15:39 ross Exp $    */

/*-
 * 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.
 */

#include <sys/param.h>
#include <sys/time.h>

#include "stand.h"

#include <vfs/ufs/dinode.h>
#include <vfs/ufs/dir.h>
#include <vfs/ufs/fs.h>
#include "string.h"

static int      ufs_open(const char *path, struct open_file *f);
static int      ufs_close(struct open_file *f);
static int      ufs_read(struct open_file *f, void *buf, size_t size, size_t *resid);
static off_t    ufs_seek(struct open_file *f, off_t offset, int where);
static int      ufs_stat(struct open_file *f, struct stat *sb);
static int      ufs_readdir(struct open_file *f, struct dirent *d);

struct fs_ops ufs_fsops = {
        "ufs",
        ufs_open,
        ufs_close,
        ufs_read,
        null_write,
        ufs_seek,
        ufs_stat,
        ufs_readdir
};

/*
 * In-core open file.
 */
struct file {
        off_t           f_seekp;        /* seek pointer */
        struct fs       *f_fs;          /* pointer to super-block */
        struct ufs1_dinode f_di;        /* copy of on-disk inode */
        int             f_nindir[UFS_NIADDR];
                                        /* number of blocks mapped by
                                           indirect block at level i */
        char            *f_blk[UFS_NIADDR];/* buffer for indirect block at
                                           level i */
        size_t          f_blksize[UFS_NIADDR];
                                        /* size of buffer */
        daddr_t         f_blkno[UFS_NIADDR];/* disk address of block in buffer */
        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(ino_t, struct open_file *);
static int      block_map(struct open_file *, daddr_t, daddr_t *);
static int      buf_read_file(struct open_file *, char **, size_t *);
static int      search_directory(char *, struct open_file *, ino_t *);
#ifdef COMPAT_UFS
static void     ffs_oldfscompat(struct fs *);
#endif

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

        if (fs == NULL)
            panic("fs == NULL");

        /*
         * Read inode and save it.
         */
        buf = malloc(fs->fs_bsize);
        twiddle();
        rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
                fsbtodb(fs, ino_to_fsba(fs, inumber)), fs->fs_bsize,
                buf, &rsize);
        if (rc)
                goto out;
        if (rsize != fs->fs_bsize) {
                rc = EIO;
                goto out;
        }

        {
                struct ufs1_dinode *dp;

                dp = (struct ufs1_dinode *)buf;
                fp->f_di = dp[ino_to_fsbo(fs, inumber)];
        }

        /*
         * Clear out the old buffers
         */
        {
                int level;

                for (level = 0; level < UFS_NIADDR; level++)
                        fp->f_blkno[level] = -1;
                fp->f_buf_blkno = -1;
        }
out:
        free(buf);
        return (rc);     
}

/*
 * Given an offset in a file, find the disk block number that
 * contains that block.
 *
 * Parameters:
 *      disk_block_p:   out
 */
static int
block_map(struct open_file *f, daddr_t file_block, daddr_t *disk_block_p)
{
        struct file *fp = (struct file *)f->f_fsdata;
        struct fs *fs = fp->f_fs;
        int level;
        int idx;
        daddr_t ind_block_num;
        daddr_t *ind_p;
        int rc;

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

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

        file_block -= UFS_NDADDR;

        /*
         * nindir[0] = NINDIR
         * nindir[1] = NINDIR**2
         * nindir[2] = NINDIR**3
         *      etc
         */
        for (level = 0; level < UFS_NIADDR; level++) {
                if (file_block < fp->f_nindir[level])
                        break;
                file_block -= fp->f_nindir[level];
        }
        if (level == UFS_NIADDR) {
                /* Block number too high */
                return (EFBIG);
        }

        ind_block_num = fp->f_di.di_ib[level];

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

                if (fp->f_blkno[level] != ind_block_num) {
                        if (fp->f_blk[level] == NULL)
                                fp->f_blk[level] =
                                        malloc(fs->fs_bsize);
                        twiddle();
                        rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
                                fsbtodb(fp->f_fs, ind_block_num),
                                fs->fs_bsize,
                                fp->f_blk[level],
                                &fp->f_blksize[level]);
                        if (rc)
                                return (rc);
                        if (fp->f_blksize[level] != fs->fs_bsize)
                                return (EIO);
                        fp->f_blkno[level] = ind_block_num;
                }

                ind_p = (daddr_t *)fp->f_blk[level];

                if (level > 0) {
                        idx = file_block / fp->f_nindir[level - 1];
                        file_block %= fp->f_nindir[level - 1];
                } else
                        idx = file_block;

                ind_block_num = ind_p[idx];
        }

        *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.
 *
 * Parameters:
 *      buf_p:  out
 *      size_p: out
 */
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 fs *fs = fp->f_fs;
        long off;
        daddr_t file_block;
        daddr_t disk_block;
        size_t block_size;
        int rc;

        off = blkoff(fs, fp->f_seekp);
        file_block = lblkno(fs, fp->f_seekp);
        block_size = dblksize(fs, &fp->f_di, file_block);

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

                if (fp->f_buf == NULL)
                        fp->f_buf = malloc(fs->fs_bsize);

                if (disk_block == 0) {
                        bzero(fp->f_buf, block_size);
                        fp->f_buf_size = block_size;
                } else {
                        twiddle();
                        rc = (f->f_dev->dv_strategy)(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.
         */
        if (*size_p > fp->f_di.di_size - fp->f_seekp)
                *size_p = fp->f_di.di_size - fp->f_seekp;

        return (0);
}

/*
 * Search a directory for a name and return its
 * i_number.
 *
 * Parameters:
 *      inumber_p:      out
 */
static int
search_directory(char *name, struct open_file *f, ino_t *inumber_p)
{
        struct file *fp = (struct file *)f->f_fsdata;
        struct direct *dp;
        struct direct *edp;
        char *buf;
        size_t buf_size;
        int namlen, length;
        int rc;

        length = strlen(name);

        fp->f_seekp = 0;
        while (fp->f_seekp < fp->f_di.di_size) {
                rc = buf_read_file(f, &buf, &buf_size);
                if (rc)
                        return (rc);

                dp = (struct direct *)buf;
                edp = (struct direct *)(buf + buf_size);
                while (dp < edp) {
                        if (dp->d_ino == (ino_t)0)
                                goto next;
                        if (dp->d_type == DT_WHT)
                                goto next;
#if BYTE_ORDER == LITTLE_ENDIAN
                        if (fp->f_fs->fs_maxsymlinklen <= 0)
                                namlen = dp->d_type;
                        else
#endif
                                namlen = dp->d_namlen;
                        if (namlen == length &&
                            !strcmp(name, dp->d_name)) {
                                /* found entry */
                                *inumber_p = dp->d_ino;
                                return (0);
                        }
                next:
                        dp = (struct direct *)((char *)dp + dp->d_reclen);
                }
                fp->f_seekp += buf_size;
        }
        return (ENOENT);
}

/*
 * Open a file.
 */
static int
ufs_open(const char *upath, struct open_file *f)
{
        char *cp, *ncp;
        int c;
        ino_t inumber, parent_inumber;
        struct file *fp;
        struct fs *fs;
        int rc;
        size_t buf_size;
        int nlinks = 0;
        char namebuf[MAXPATHLEN+1];
        char *buf = NULL;
        char *path = NULL;

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

        /* allocate space and read super block */
        fs = malloc(SBSIZE);
        fp->f_fs = fs;
        twiddle();
        rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
                SBOFF / DEV_BSIZE, SBSIZE, (char *)fs, &buf_size);
        if (rc)
                goto out;

        if (buf_size != SBSIZE || fs->fs_magic != FS_MAGIC ||
            fs->fs_bsize > MAXBSIZE || fs->fs_bsize < sizeof(struct fs)) {
                rc = EINVAL;
                goto out;
        }
#ifdef COMPAT_UFS
        ffs_oldfscompat(fs);
#endif

        /*
         * Calculate indirect block levels.
         */
        {
                int omult;
                int mult;
                int level;

                omult = 0;
                mult = 1;
                for (level = 0; level < UFS_NIADDR; level++) {
                        mult *= NINDIR(fs);
                        if (mult < omult)
                                mult = 0x7FFFFFFF;
                        fp->f_nindir[level] = mult;
                        omult = mult;
                }
        }

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

        cp = path = strdup(upath);
        if (path == NULL) {
            rc = ENOMEM;
            goto out;
        }
        while (*cp) {

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

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

                /*
                 * Get next component of path name.
                 */
                {
                        int len = 0;

                        ncp = cp;
                        while ((c = *cp) != '\0' && c != '/') {
                                if (++len > MAXNAMLEN) {
                                        rc = ENOENT;
                                        goto out;
                                }
                                cp++;
                        }
                        *cp = '\0';
                }

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

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

                /*
                 * Check for symbolic link.
                 */
                if ((fp->f_di.di_mode & IFMT) == IFLNK) {
                        int link_len = fp->f_di.di_size;
                        int len;

                        len = strlen(cp);

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

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

                        if (link_len < fs->fs_maxsymlinklen) {
                                bcopy(fp->f_di.di_shortlink, namebuf,
                                      (unsigned) link_len);
                        } else {
                                /*
                                 * Read file for symbolic link
                                 */
                                size_t buf_size;
                                daddr_t disk_block;
                                struct fs *fs = fp->f_fs;

                                if (!buf)
                                        buf = malloc(fs->fs_bsize);
                                rc = block_map(f, (daddr_t)0, &disk_block);
                                if (rc)
                                        goto out;
                                
                                twiddle();
                                rc = (f->f_dev->dv_strategy)(f->f_devdata,
                                        F_READ, fsbtodb(fs, disk_block),
                                        fs->fs_bsize, buf, &buf_size);
                                if (rc)
                                        goto out;

                                bcopy((char *)buf, namebuf, (unsigned)link_len);
                        }

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

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

        /*
         * Found terminal component.
         */
        fp->f_seekp = 0;
        rc = 0;
out:
        if (buf)
                free(buf);
        if (path)
                free(path);
        if (rc) {
                f->f_fsdata = NULL;
                if (fp->f_buf)
                        free(fp->f_buf);
                free(fp->f_fs);
                free(fp);
        }
        return (rc);
}

static int
ufs_close(struct open_file *f)
{
        struct file *fp = (struct file *)f->f_fsdata;
        int level;

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

        for (level = 0; level < UFS_NIADDR; level++) {
                if (fp->f_blk[level])
                        free(fp->f_blk[level]);
        }
        if (fp->f_buf)
                free(fp->f_buf);
        free(fp->f_fs);
        free(fp);
        return (0);
}

/*
 * Copy a portion of a file into kernel memory.
 * Cross block boundaries when necessary.
 *
 * Parameters:
 *      resid:  out
 */
static int
ufs_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 >= fp->f_di.di_size)
                        break;

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

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

                bcopy(buf, addr, csize);

                fp->f_seekp += csize;
                addr += csize;
                size -= csize;
        }
        if (resid)
                *resid = size;
        return (rc);
}

static off_t
ufs_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.di_size - offset;
                break;
        default:
                return (-1);
        }
        return (fp->f_seekp);
}

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

        /* only important stuff */
        sb->st_mode = fp->f_di.di_mode;
        sb->st_uid = fp->f_di.di_uid;
        sb->st_gid = fp->f_di.di_gid;
        sb->st_size = fp->f_di.di_size;
        return (0);
}

static int
ufs_readdir(struct open_file *f, struct dirent *d)
{
        struct file *fp = (struct file *)f->f_fsdata;
        struct direct *dp;
        char *buf;
        size_t buf_size;
        int error;

        /*
         * assume that a directory entry will not be split across blocks
         */
again:
        if (fp->f_seekp >= fp->f_di.di_size)
                return (ENOENT);
        error = buf_read_file(f, &buf, &buf_size);
        if (error)
                return (error);
        dp = (struct direct *)buf;
        fp->f_seekp += dp->d_reclen;
        if (dp->d_ino == (ino_t)0)
                goto again;
        d->d_type = dp->d_type;
        strcpy(d->d_name, dp->d_name);
        return (0);
}

#ifdef COMPAT_UFS
/*
 * Sanity checks for old file systems.
 *
 * XXX - goes away some day.
 */
static void
ffs_oldfscompat(struct fs *fs)
{
        int i;

        fs->fs_npsect = max(fs->fs_npsect, fs->fs_nsect);       /* XXX */
        fs->fs_interleave = max(fs->fs_interleave, 1);          /* XXX */
        if (fs->fs_postblformat == FS_42POSTBLFMT)              /* XXX */
                fs->fs_nrpos = 8;                               /* XXX */
        if (fs->fs_inodefmt < FS_44INODEFMT) {                  /* XXX */
                quad_t sizepb = fs->fs_bsize;                   /* XXX */
                                                                /* XXX */
                fs->fs_maxfilesize = fs->fs_bsize * UFS_NDADDR - 1; /* XXX */
                for (i = 0; i < UFS_NIADDR; i++) {              /* XXX */
                        sizepb *= NINDIR(fs);                   /* XXX */
                        fs->fs_maxfilesize += sizepb;           /* XXX */
                }                                               /* XXX */
                fs->fs_qbmask = ~fs->fs_bmask;                  /* XXX */
                fs->fs_qfmask = ~fs->fs_fmask;                  /* XXX */
        }                                                       /* XXX */
}
#endif