/*      $NetBSD: ext2fs.c,v 1.9 2013/06/23 02:06:06 dholland 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) 2002 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Fredette.
*
* 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 NETBSD FOUNDATION, INC. 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.
*/

#if HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
#endif

#include <sys/cdefs.h>
#if !defined(__lint)
__RCSID("$NetBSD: ext2fs.c,v 1.9 2013/06/23 02:06:06 dholland Exp $");
#endif  /* !__lint */

#include <sys/param.h>

#if !HAVE_NBTOOL_CONFIG_H
#include <sys/mount.h>
#endif

#include <assert.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "installboot.h"

#include <ufs/ext2fs/ext2fs_dinode.h>
#include <ufs/ext2fs/ext2fs_dir.h>
#include <ufs/ext2fs/ext2fs.h>

static int      ext2fs_read_disk_block(ib_params *, uint64_t, int, uint8_t []);
static int      ext2fs_read_sblock(ib_params *, struct m_ext2fs *fs);
static int      ext2fs_read_gdblock(ib_params *, struct m_ext2fs *fs);
static int      ext2fs_find_disk_blocks(ib_params *, ino_t,
                   int (*)(ib_params *, void *, uint64_t, uint32_t), void *);
static int      ext2fs_findstage2_ino(ib_params *, void *, uint64_t, uint32_t);
static int      ext2fs_findstage2_blocks(ib_params *, void *, uint64_t,
                   uint32_t);


/* This reads a disk block from the file system. */
/* XXX: should be shared with ffs.c? */
static int
ext2fs_read_disk_block(ib_params *params, uint64_t blkno, int size,
   uint8_t blk[])
{
       int rv;

       assert(params != NULL);
       assert(params->filesystem != NULL);
       assert(params->fsfd != -1);
       assert(size > 0);
       assert(blk != NULL);

       rv = pread(params->fsfd, blk, size, blkno * params->sectorsize);
       if (rv == -1) {
               warn("Reading block %llu in `%s'",
                   (unsigned long long)blkno, params->filesystem);
               return 0;
       } else if (rv != size) {
               warnx("Reading block %llu in `%s': short read",
                   (unsigned long long)blkno, params->filesystem);
               return 0;
       }

       return 1;
}

static int
ext2fs_read_sblock(ib_params *params, struct m_ext2fs *fs)
{
       uint8_t sbbuf[SBSIZE];

       if (ext2fs_read_disk_block(params, SBOFF / params->sectorsize, SBSIZE,
           sbbuf) == 0)

       e2fs_sbload((void *)sbbuf, &fs->e2fs);

       if (fs->e2fs.e2fs_magic != E2FS_MAGIC)
               return 0;

       if (fs->e2fs.e2fs_rev > E2FS_REV1 ||
           (fs->e2fs.e2fs_rev == E2FS_REV1 &&
            (fs->e2fs.e2fs_first_ino != EXT2_FIRSTINO ||
             fs->e2fs.e2fs_inode_size != EXT2_DINODE_SIZE ||
             (fs->e2fs.e2fs_features_incompat & ~EXT2F_INCOMPAT_SUPP) != 0)))
               return 0;

       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 / EXT2_DINODE_SIZE;
       fs->e2fs_itpg = fs->e2fs.e2fs_ipg / fs->e2fs_ipb;

       return 1;
}

static int
ext2fs_read_gdblock(ib_params *params, struct m_ext2fs *fs)
{
       uint8_t gdbuf[MAXBSIZE];
       uint32_t gdpb;
       int i;

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

       for (i = 0; i < fs->e2fs_ngdb; i++) {
               if (ext2fs_read_disk_block(params, EXT2_FSBTODB(fs,
                   fs->e2fs.e2fs_first_dblock + 1 /* superblock */ + i),
                   SBSIZE, gdbuf) == 0)
                       return 0;

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

       return 1;
}

/*
* This iterates over the data blocks belonging to an inode,
* making a callback each iteration with the disk block number
* and the size.
*/
static int
ext2fs_find_disk_blocks(ib_params *params, ino_t ino,
       int (*callback)(ib_params *, void *, uint64_t, uint32_t),
       void *state)
{
       uint8_t sbbuf[sizeof(struct m_ext2fs)];
       struct m_ext2fs *fs;
       uint8_t inodebuf[MAXBSIZE];
       struct ext2fs_dinode inode_store, *inode;
       int level_i;
       int32_t blk, lblk, nblk;
       int rv;
#define LEVELS 4
       struct {
               uint32_t *blknums;
               unsigned long blkcount;
               uint8_t diskbuf[MAXBSIZE];
       } level[LEVELS];

       assert(params != NULL);
       assert(params->fstype != NULL);
       assert(callback != NULL);
       assert(state != NULL);

       /* Read the superblock. */
       fs = (void *)sbbuf;
       if (ext2fs_read_sblock(params, fs) == 0)
               return 0;

       fs->e2fs_gd = malloc(sizeof(struct ext2_gd) * fs->e2fs_ncg);
       if (fs->e2fs_gd == NULL) {
               warnx("Can't allocate memofy for group descriptors");
               return 0;
       }

       if (ext2fs_read_gdblock(params, fs) == 0) {
               warnx("Can't read group descriptors");
               return 0;
       }

       if (fs->e2fs_ipb <= 0) {
               warnx("Bad ipb %d in superblock in `%s'",
                   fs->e2fs_ipb, params->filesystem);
               return 0;
       }

       /* Read the inode. */
       if (ext2fs_read_disk_block(params,
               EXT2_FSBTODB(fs, ino_to_fsba(fs, ino)) + params->fstype->offset,
               fs->e2fs_bsize, inodebuf))
               return 0;
       inode = (void *)inodebuf;
       e2fs_iload(&inode[ino_to_fsbo(fs, ino)], &inode_store);
       inode = &inode_store;

       /* Get the block count and initialize for our block walk. */
       nblk = howmany(inode->e2di_size, fs->e2fs_bsize);
       lblk = 0;
       level_i = 0;
       level[0].blknums = &inode->e2di_blocks[0];
       level[0].blkcount = UFS_NDADDR;
       level[1].blknums = &inode->e2di_blocks[UFS_NDADDR + 0];
       level[1].blkcount = 1;
       level[2].blknums = &inode->e2di_blocks[UFS_NDADDR + 1];
       level[2].blkcount = 1;
       level[3].blknums = &inode->e2di_blocks[UFS_NDADDR + 2];
       level[3].blkcount = 1;

       /* Walk the data blocks. */
       while (nblk > 0) {

               /*
                * If there are no more blocks at this indirection
                * level, move up one indirection level and loop.
                */
               if (level[level_i].blkcount == 0) {
                       if (++level_i == LEVELS)
                               break;
                       continue;
               }

               /* Get the next block at this level. */
               blk = fs2h32(*(level[level_i].blknums++));
               level[level_i].blkcount--;

#if 0
               fprintf(stderr, "ino %lu blk %lu level %d\n", ino, blk,
                   level_i);
#endif

               /*
                * If we're not at the direct level, descend one
                * level, read in that level's new block list,
                * and loop.
                */
               if (level_i > 0) {
                       level_i--;
                       if (blk == 0)
                               memset(level[level_i].diskbuf, 0, MAXBSIZE);
                       else if (ext2fs_read_disk_block(params,
                               EXT2_FSBTODB(fs, blk) + params->fstype->offset,
                               fs->e2fs_bsize, level[level_i].diskbuf) == 0)
                               return 0;
                       /* XXX ondisk32 */
                       level[level_i].blknums =
                           (uint32_t *)level[level_i].diskbuf;
                       level[level_i].blkcount = EXT2_NINDIR(fs);
                       continue;
               }

               /* blk is the next direct level block. */
#if 0
               fprintf(stderr, "ino %lu db %lu blksize %lu\n", ino,
                   EXT2_FSBTODB(fs, blk), ext2_sblksize(fs, inode->di_size, lblk));
#endif
               rv = (*callback)(params, state,
                   EXT2_FSBTODB(fs, blk) + params->fstype->offset, fs->e2fs_bsize);
               lblk++;
               nblk--;
               if (rv != 1)
                       return rv;
       }

       if (nblk != 0) {
               warnx("Inode %llu in `%s' ran out of blocks?",
                   (unsigned long long)ino, params->filesystem);
               return 0;
       }

       return 1;
}

/*
* This callback reads a block of the root directory,
* searches for an entry for the secondary bootstrap,
* and saves the inode number if one is found.
*/
static int
ext2fs_findstage2_ino(ib_params *params, void *_ino,
       uint64_t blk, uint32_t blksize)
{
       uint8_t dirbuf[MAXBSIZE];
       struct ext2fs_direct *de, *ede;
       uint32_t ino;

       assert(params != NULL);
       assert(params->fstype != NULL);
       assert(params->stage2 != NULL);
       assert(_ino != NULL);

       /* Skip directory holes. */
       if (blk == 0)
               return 1;

       /* Read the directory block. */
       if (ext2fs_read_disk_block(params, blk, blksize, dirbuf) == 0)
               return 0;

       /* Loop over the directory entries. */
       de = (struct ext2fs_direct *)&dirbuf[0];
       ede = (struct ext2fs_direct *)&dirbuf[blksize];
       while (de < ede) {
               ino = fs2h32(de->e2d_ino);
               if (ino != 0 && strcmp(de->e2d_name, params->stage2) == 0) {
                       *((uint32_t *)_ino) = ino;
                       return (2);
               }
               if (fs2h16(de->e2d_reclen) == 0)
                       break;
               de = (struct ext2fs_direct *)((char *)de +
                   fs2h16(de->e2d_reclen));
       }

       return 1;
}

struct findblks_state {
       uint32_t        maxblk;
       uint32_t        nblk;
       ib_block        *blocks;
};

/* This callback records the blocks of the secondary bootstrap. */
static int
ext2fs_findstage2_blocks(ib_params *params, void *_state,
       uint64_t blk, uint32_t blksize)
{
       struct findblks_state *state = _state;

       assert(params != NULL);
       assert(params->stage2 != NULL);
       assert(_state != NULL);

       if (state->nblk == state->maxblk) {
               warnx("Secondary bootstrap `%s' has too many blocks (max %d)",
                   params->stage2, state->maxblk);
               return (0);
       }
       state->blocks[state->nblk].block = blk;
       state->blocks[state->nblk].blocksize = blksize;
       state->nblk++;
       return 1;
}

/*
*      publicly visible functions
*/

int
ext2fs_match(ib_params *params)
{
       uint8_t sbbuf[sizeof(struct m_ext2fs)];
       struct m_ext2fs *fs;

       assert(params != NULL);
       assert(params->fstype != NULL);

       /* Read the superblock. */
       fs = (void *)sbbuf;
       if (ext2fs_read_sblock(params, fs) == 0)
               return 0;

       params->fstype->needswap = 0;
       params->fstype->blocksize = fs->e2fs_bsize;
       params->fstype->offset = 0;

       return 1;
}

int
ext2fs_findstage2(ib_params *params, uint32_t *maxblk, ib_block *blocks)
{
       int rv;
       uint32_t ino;
       struct findblks_state state;

       assert(params != NULL);
       assert(params->stage2 != NULL);
       assert(maxblk != NULL);
       assert(blocks != NULL);

       if (params->flags & IB_STAGE2START)
               return hardcode_stage2(params, maxblk, blocks);

       /* The secondary bootstrap must be clearly in /. */
       if (params->stage2[0] == '/')
               params->stage2++;
       if (strchr(params->stage2, '/') != NULL) {
               warnx("The secondary bootstrap `%s' must be in /",
                   params->stage2);
               warnx("(Path must be relative to the file system in `%s')",
                   params->filesystem);
               return 0;
       }

       /* Get the inode number of the secondary bootstrap. */
       rv = ext2fs_find_disk_blocks(params, EXT2_ROOTINO,
           ext2fs_findstage2_ino, &ino);
       if (rv != 2) {
               warnx("Could not find secondary bootstrap `%s' in `%s'",
                   params->stage2, params->filesystem);
               warnx("(Path must be relative to the file system in `%s')",
                   params->filesystem);
               return 0;
       }

       /* Record the disk blocks of the secondary bootstrap. */
       state.maxblk = *maxblk;
       state.nblk = 0;
       state.blocks = blocks;
               rv = ext2fs_find_disk_blocks(params, ino,
                   ext2fs_findstage2_blocks, &state);
       if (rv == 0)
               return 0;

       *maxblk = state.nblk;
       return 1;
}

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