[apple/hfs.git] / hfs_util / hfsutil_jnl.c

/*
 * Copyright (c) 1999-2014 Apple Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.2 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 Copyright (c) 2002 Apple Computer, Inc.
 All Rights Reserved.

 This file contains the routine to make an HFS+ volume journaled
 and a corresponding routine to turn it off.
 
 */

#include <sys/types.h>
#include <sys/attr.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/sysctl.h>
#include <sys/resource.h>
#include <sys/vmmeter.h>
#include <sys/mount.h>
#include <sys/wait.h>
#include <sys/ioctl.h>

#include <sys/disk.h>
#include <sys/loadable_fs.h>
#include <hfs/hfs_format.h>
#include <hfs/hfs_mount.h>    /* for hfs sysctl values */

#include <System/hfs/hfs_fsctl.h>

#include <System/sys/content_protection.h>
#include <TargetConditionals.h>

#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <architecture/byte_order.h>

// just in case these aren't in <hfs/hfs_mount.h> yet
#ifndef HFS_ENABLE_JOURNALING
#define HFS_ENABLE_JOURNALING   0x082969
#endif
#ifndef HFS_DISABLE_JOURNALING
#define HFS_DISABLE_JOURNALING 0x031272
#endif
#ifndef HFS_GET_JOURNAL_INFO
#define HFS_GET_JOURNAL_INFO    0x6a6e6c69
#endif

/* getattrlist buffers start with an extra length field */
struct ExtentsAttrBuf {
        unsigned long   infoLength;
        HFSPlusExtentRecord     extents;
};
typedef struct ExtentsAttrBuf ExtentsAttrBuf;

#ifndef HFSIOC_GET_JOURNAL_INFO
# include <sys/ioctl.h>
struct hfs_journal_info {
        off_t   jstart;
        off_t   jsize;
};
# define HFSIOC_GET_JOURNAL_INFO        _IOR('h', 17, struct hfs_journal_info)
#endif


#define kIsInvisible 0x4000

/*
 * Generic Finder file/dir data
 */
struct FinderInfo {
        u_int32_t       opaque_1[2];
        u_int16_t       fdFlags;        /* Finder flags */
        int16_t         opaque_2[11];
};
typedef struct FinderInfo FinderInfo;

/* getattrlist buffers start with an extra length field */
struct FinderAttrBuf {
        unsigned long   infoLength;
        FinderInfo      finderInfo;
};
typedef struct FinderAttrBuf FinderAttrBuf;


int hide_file(const char * file)
{
    struct attrlist alist = {0};
    FinderAttrBuf finderInfoBuf = {0};
    int result;
    
    alist.bitmapcount = ATTR_BIT_MAP_COUNT;
    alist.commonattr = ATTR_CMN_FNDRINFO;

    result = getattrlist(file, &alist, &finderInfoBuf, sizeof(finderInfoBuf), 0);
    if (result) {
        return (errno);
    }
        
    if (finderInfoBuf.finderInfo.fdFlags & kIsInvisible) {
        printf("hide: %s is alreadly invisible\n", file);
        return (0);
    }

    finderInfoBuf.finderInfo.fdFlags |= kIsInvisible;

    result = setattrlist(file, &alist, &finderInfoBuf.finderInfo, sizeof(FinderInfo), 0);
    
    return (result == -1 ? errno : result);
}

off_t
get_start_block(const char *file, uint32_t fs_block_size)
{
    off_t cur_pos, phys_start, len;
    int fd, err;
    struct log2phys l2p;
    struct stat st;

    fd = open(file, O_RDONLY);
    if (fd < 0) {
        return -1;
    }

    if (fstat(fd, &st) < 0) {
        fprintf(stderr, "can't stat %s (%s)\n", file, strerror(errno));
        close(fd);
        return -1;
    }

    fs_block_size = st.st_blksize; // XXXdbg quick hack for now

    phys_start = len = 0;
    for(cur_pos=0; cur_pos < st.st_size; cur_pos += fs_block_size) {
        memset(&l2p, 0, sizeof(l2p));
        lseek(fd, cur_pos, SEEK_SET);
        err = fcntl(fd, F_LOG2PHYS, &l2p);

        if (phys_start == 0) {
            phys_start = l2p.l2p_devoffset;
            len = fs_block_size;
        } else if (l2p.l2p_devoffset != (phys_start + len)) {
            // printf("    %lld : %lld - %lld\n", cur_pos, phys_start / fs_block_size, len / fs_block_size);
            fprintf(stderr, "%s : is not contiguous!\n", file);
            close(fd);
            return -1;
            // phys_start = l2p.l2p_devoffset;
            // len = fs_block_size;
        } else {
            len += fs_block_size;
        }
    }

    close(fd);

    //printf("%s start offset %lld; byte len %lld (blksize %d)\n",
    // file, phys_start, len, fs_block_size);

    if ((phys_start / (unsigned int)fs_block_size) & 0xffffffff00000000LL) {
        fprintf(stderr, "%s : starting block is > 32bits!\n", file);
        return -1;
    }
        
    return phys_start;
}


//
// Get the embedded offset (if any) for an hfs+ volume.
// This is pretty skanky that we have to do this but
// that's life...
//
#include <sys/disk.h>
#include <hfs/hfs_format.h>

#include <machine/endian.h>

#define HFS_PRI_SECTOR(blksize)          (1024 / (blksize))
#define HFS_PRI_OFFSET(blksize)          ((blksize) > 1024 ? 1024 : 0)

#include <libkern/OSByteOrder.h>

#define SWAP_BE16(x) ntohs(x)
#define SWAP_BE32(x) ntohl(x)
#define SWAP_BE64(x) OSSwapConstInt64(x)


off_t
get_embedded_offset(char *devname)
{
    int fd = -1;
    off_t ret = 0;
    char *buff = NULL, rawdev[256];
    u_int64_t blkcnt;
    u_int32_t blksize;
    HFSMasterDirectoryBlock *mdbp;
    off_t embeddedOffset;
    struct statfs sfs;
    struct stat   st;
        
  restart:
    if (stat(devname, &st) != 0) {
        fprintf(stderr, "Could not access %s (%s)\n", devname, strerror(errno));
        ret = -1;
        goto out;
    }

    if (S_ISCHR(st.st_mode) == 0) {
        // hmmm, it's not the character special raw device so we
        // should try to figure out the real device.
        if (statfs(devname, &sfs) != 0) {
            fprintf(stderr, "Can't find out any info about the fs for path %s (%s)\n",
                devname, strerror(errno));
            ret = -1;
            goto out;
        }

        // This assumes it begins with "/dev/".  The old code assumed
        // it began with five characters.  Should probably use strrchr or equivalent.
        snprintf(rawdev, sizeof(rawdev), "/dev/r%s", &sfs.f_mntfromname[5]);
        devname = &rawdev[0];
        goto restart;
    }

    fd = open(devname, O_RDONLY);
    if (fd < 0) {
        fprintf(stderr, "can't open: %s (%s)\n", devname, strerror(errno));
        ret = -1;
        goto out;
    }

    /* Get the real physical block size. */
    if (ioctl(fd, DKIOCGETBLOCKSIZE, (caddr_t)&blksize) != 0) {
        fprintf(stderr, "can't get the device block size (%s). assuming 512\n", strerror(errno));
        blksize = 512;
        ret = -1;
        goto out;
    }

    /* Get the number of physical blocks. */
    if (ioctl(fd, DKIOCGETBLOCKCOUNT, (caddr_t)&blkcnt)) {
        struct stat st;
        fprintf(stderr, "failed to get block count. trying stat().\n");
        if (fstat(fd, &st) != 0) {
            ret = -1;
            goto out;
        }

        blkcnt = st.st_size / blksize;
    }

    /*
     * At this point:
     *   blksize has our prefered physical block size
     *   blkcnt has the total number of physical blocks
     */

    buff = (char *)malloc(blksize);
        
    if (pread(fd, buff, blksize, HFS_PRI_SECTOR(blksize)*blksize) != blksize) {
                fprintf(stderr, "failed to read volume header @ offset %d (%s)\n",
                                HFS_PRI_SECTOR(blksize), strerror(errno));
                ret = -1;
                goto out;
    }

        mdbp = (HFSMasterDirectoryBlock *)(buff + HFS_PRI_OFFSET(blksize));
        if (   (SWAP_BE16(mdbp->drSigWord) != kHFSSigWord) 
                        && (SWAP_BE16(mdbp->drSigWord) != kHFSPlusSigWord)
                        && (SWAP_BE16(mdbp->drSigWord) != kHFSXSigWord)) {
                printf ("get_embedded_offset: invalid volume signature \n");
                ret = -1;
                goto out;
        }

    if ((SWAP_BE16(mdbp->drSigWord) == kHFSSigWord) && (SWAP_BE16(mdbp->drEmbedSigWord) != kHFSPlusSigWord)) {
        ret = -1;
        goto out;
    } else if (SWAP_BE16(mdbp->drEmbedSigWord) == kHFSPlusSigWord) {
        /* Get the embedded Volume Header */
        embeddedOffset = SWAP_BE16(mdbp->drAlBlSt) * 512;
        embeddedOffset += (u_int64_t)SWAP_BE16(mdbp->drEmbedExtent.startBlock) *
                          (u_int64_t)SWAP_BE32(mdbp->drAlBlkSiz);

        /*
         * If the embedded volume doesn't start on a block
         * boundary, then switch the device to a 512-byte
         * block size so everything will line up on a block
         * boundary.
         */
        if ((embeddedOffset % blksize) != 0) {
            fprintf(stderr, "HFS Mount: embedded volume offset not"
                " a multiple of physical block size (%d);"
                " switching to 512\n", blksize);
                
            blkcnt  *= (blksize / 512);
            blksize  = 512;
        }

    } else { /* pure HFS+ */ 
        embeddedOffset = 0;
    }

    ret = embeddedOffset;

  out:
    if (buff) {
        free(buff);
    }
    if (fd >= 0) 
        close(fd);

    return ret;
}



static const char *journal_fname = ".journal";
static const char *jib_fname = ".journal_info_block";

int 
DoMakeJournaled(char *volname, int jsize) {
        int              fd, i, block_size, journal_size = 8*1024*1024;
        char            *buf;
        int              ret;
        fstore_t         fst;
        int32_t          jstart_block, jinfo_block;
        int              sysctl_info[8];
        JournalInfoBlock jib;
        struct statfs    sfs;
        static char      tmpname[MAXPATHLEN];
        off_t            start_block, embedded_offset;

        if (statfs(volname, &sfs) != 0) {
                fprintf(stderr, "Can't stat volume %s (%s).\n", volname, strerror(errno));
                return 10;
        }

        // Make sure that we're HFS+.  First we check the fstypename.
        // If that's ok then we try to create a symlink (which won't
        // work on plain hfs volumes but will work on hfs+ volumes).
        //
        if (strcmp(sfs.f_fstypename, "devfs") == 0) {
                fprintf (stderr, "%s is a device node.  Journal enable only works on a mounted HFS+ volume.\n", volname);
                return 10;
        }
        snprintf(tmpname, sizeof(tmpname), "%s/is_vol_hfs_plus", volname);
        if (strcmp(sfs.f_fstypename, "hfs") != 0 ||
                        ((ret = symlink(tmpname, tmpname)) != 0 && errno == ENOTSUP)) {
                fprintf(stderr, "%s is not an HFS+ volume.  Journaling only works on HFS+ volumes.\n",
                                volname);
                return 10;
        }
        unlink(tmpname);

        if (sfs.f_flags & MNT_JOURNALED) {
                fprintf(stderr, "Volume %s is already journaled.\n", volname);
                return 1;
        }

        if (jsize != 0) {
                journal_size = jsize;
        } else {
                int scale;

                //
                // we want at least 8 megs of journal for each 100 gigs of
                // disk space.  We cap the size at 512 megs though.
                //
                scale = ((long long)sfs.f_bsize * (long long)((unsigned int)sfs.f_blocks)) / (100*1024*1024*1024ULL);
                journal_size *= (scale + 1);
                if (journal_size > 512 * 1024 * 1024) {
                        journal_size = 512 * 1024 * 1024;
                }
        }

        if (chdir(volname) != 0) {
                fprintf(stderr, "Can't locate volume %s to make it journaled (%s).\n",
                                volname, strerror(errno));
                return 10;
        }


        embedded_offset = get_embedded_offset(volname);
        if (embedded_offset < 0) {
                fprintf(stderr, "Can't calculate the embedded offset (if any) for %s.\n", volname);
                fprintf(stderr, "Journal creation failure.\n");
                return 15;
        }
        // printf("Embedded offset == 0x%llx\n", embedded_offset);

        /* 
         * Must use open_dprotected_np to create a class D file.  This will
         * be the same as standard open(2) on systems that do not support content protection
         */
        fd = open_dprotected_np (journal_fname, O_CREAT|O_TRUNC|O_RDWR, PROTECTION_CLASS_D, 0, 000);
        if (fd < 0) {
                fprintf(stderr, "Can't create journal file on volume %s (%s)\n",
                                volname, strerror(errno));
                return 5;
        }

        if (fcntl(fd, F_NOCACHE, 1)) {
                fprintf(stderr, "Can't create journal file (NC)  on volume %s (%s)\n",
                                volname, strerror(errno));
                return 5;       
        }


        // make sure that it has no r/w/x privs (only could happen if
        // the file already existed since open() doesn't reset the mode
        // bits).
        //
        fchmod(fd, 0);

        block_size = sfs.f_bsize;
        if ((journal_size % block_size) != 0) {
                fprintf(stderr, "Journal size %dk is not a multiple of volume %s block size (%d).\n",
                                journal_size/1024, volname, block_size);
                close(fd);
                unlink(journal_fname);
                return 5;
        }

retry:
        memset(&fst, 0, sizeof(fst));
        fst.fst_flags   = F_ALLOCATECONTIG|F_ALLOCATEALL;
        fst.fst_length  = journal_size;
        fst.fst_posmode = F_PEOFPOSMODE;

        ret = fcntl(fd, F_PREALLOCATE, &fst);
        if (ret < 0) {
                if (journal_size >= 2*1024*1024) {
                        fprintf(stderr, "Not enough contiguous space for a %d k journal.  Retrying.\n",
                                        journal_size/1024);
                        journal_size /= 2;
                        ftruncate(fd, 0);     // make sure the file is zero bytes long.
                        goto retry;
                } else {
                        fprintf(stderr, "Disk too fragmented to enable journaling.\n");
                        fprintf(stderr, "Please run a defragmenter on %s.\n", volname);
                        close(fd);
                        unlink(journal_fname);
                        return 10;
                }
        }

        printf("Allocated %lldK for journal file.\n", fst.fst_bytesalloc/1024LL);
        buf = (char *)calloc(block_size, 1);
        if (buf) {
                for(i=0; i < journal_size/block_size; i++) {
                        ret = write(fd, buf, block_size);
                        if (ret != block_size) {
                                break;
                        }
                }

                if (i*block_size != journal_size) {
                        fprintf(stderr, "Failed to write %dk to journal on volume %s (%s)\n",
                                        journal_size/1024, volname, strerror(errno));
                }
        } else {
                printf("Could not allocate memory to write to the journal on volume %s (%s)\n",
                                volname, strerror(errno));
        }

        fsync(fd);
        close(fd);
        hide_file(journal_fname);

        start_block = get_start_block(journal_fname, block_size);
        if (start_block == (off_t)-1) {
                fprintf(stderr, "Failed to get start block for %s (%s)\n",
                                journal_fname, strerror(errno));
                unlink(journal_fname);
                return 20;
        }
        jstart_block = (start_block / block_size) - (embedded_offset / block_size);

        memset(&jib, 'Z', sizeof(jib));
        jib.flags  = kJIJournalInFSMask;
        jib.offset = (off_t)((unsigned int)jstart_block) * (off_t)((unsigned int)block_size);
        jib.size   = (off_t)((unsigned int)journal_size);

        /* 
         * Use open_dprotected_np to create JIB as a class D file.  This will
         * behave the same as a standard open(2) on systems that do not support content protection
         */
        fd = open_dprotected_np(jib_fname, O_CREAT|O_TRUNC|O_RDWR, PROTECTION_CLASS_D, 0, 000);
        if (fd < 0) {
                fprintf(stderr, "Could not create journal info block file on volume %s (%s)\n",
                                volname, strerror(errno));
                unlink(journal_fname);
                return 5;
        }

        if (fcntl(fd, F_NOCACHE, 1)) {
                fprintf(stderr, "Could not create journal info block (NC) file on volume %s (%s)\n",
                                volname, strerror(errno));
                return 5;       
        } 

        // swap the data before we copy it
        jib.flags  = OSSwapBigToHostInt32(jib.flags);
        jib.offset = OSSwapBigToHostInt64(jib.offset);
        jib.size   = OSSwapBigToHostInt64(jib.size);

        memcpy(buf, &jib, sizeof(jib));

        // now put it back the way it was
        jib.size   = OSSwapBigToHostInt64(jib.size);
        jib.offset = OSSwapBigToHostInt64(jib.offset);
        jib.flags  = OSSwapBigToHostInt32(jib.flags);

        if (write(fd, buf, block_size) != block_size) {
                fprintf(stderr, "Failed to write journal info block on volume %s (%s)!\n",
                                volname, strerror(errno));
                unlink(journal_fname);
                return 10;
        }

        fsync(fd);
        close(fd);
        hide_file(jib_fname);

        start_block = get_start_block(jib_fname, block_size);
        if (start_block == (off_t)-1) {
                fprintf(stderr, "Failed to get start block for %s (%s)\n",
                                jib_fname, strerror(errno));
                unlink(journal_fname);
                unlink(jib_fname);
                return 20;
        }
        jinfo_block = (start_block / block_size) - (embedded_offset / block_size);


        //
        // Now make the volume journaled!
        //
        memset(sysctl_info, 0, sizeof(sysctl_info));
        sysctl_info[0] = CTL_VFS;
        sysctl_info[1] = sfs.f_fsid.val[1];
        sysctl_info[2] = HFS_ENABLE_JOURNALING;
        sysctl_info[3] = jinfo_block;
        sysctl_info[4] = jstart_block;
        sysctl_info[5] = journal_size;

        //printf("fs type: 0x%x\n", sysctl_info[1]);
        //printf("jinfo block : 0x%x\n", jinfo_block);
        //printf("jstart block: 0x%x\n", jstart_block);
        //printf("journal size: 0x%x\n", journal_size);

        ret = sysctl((void *)sysctl_info, 6, NULL, NULL, NULL, 0);
        if (ret != 0) {
                fprintf(stderr, "Failed to make volume %s journaled (%s)\n",
                                volname, strerror(errno));
                unlink(journal_fname);
                unlink(jib_fname);
                return 20;
        }

        return 0;
}


int
DoUnJournal(char *volname) {
        int           result;
        int           sysctl_info[8];
        struct statfs sfs;
        char          jbuf[MAXPATHLEN];

        if (statfs(volname, &sfs) != 0) {
                fprintf(stderr, "Can't stat volume %s (%s).\n", volname, strerror(errno));
                return 10;
        }

        if (strcmp(sfs.f_fstypename, "hfs") != 0) {
                fprintf(stderr, "Volume %s (%s) is not a HFS volume.\n", volname, sfs.f_mntfromname);
                return 1;
        }

        if ((sfs.f_flags & MNT_JOURNALED) == 0) {
                fprintf(stderr, "Volume %s (%s) is not journaled.\n", volname, sfs.f_mntfromname);
                return 1;
        }

        if (chdir(volname) != 0) {
                fprintf(stderr, "Can't locate volume %s to turn off journaling (%s).\n",
                                volname, strerror(errno));
                return 10;
        }

        memset(sysctl_info, 0, sizeof(sysctl_info));
        sysctl_info[0] = CTL_VFS;
        sysctl_info[1] = sfs.f_fsid.val[1];
        sysctl_info[2] = HFS_DISABLE_JOURNALING;

        result = sysctl((void *)sysctl_info, 3, NULL, NULL, NULL, 0);
        if (result != 0) {
                fprintf(stderr, "Failed to make volume %s UN-journaled (%s)\n",
                                volname, strerror(errno));
                return 20;
        }

        snprintf(jbuf, sizeof(jbuf), "%s/%s", volname, journal_fname);
        if (unlink(jbuf) != 0) {
                fprintf(stderr, "Failed to remove the journal %s (%s)\n",
                                jbuf, strerror(errno));
        }

        snprintf(jbuf, sizeof(jbuf), "%s/%s", volname, jib_fname);
        if (unlink(jbuf) != 0) {
                fprintf(stderr, "Failed to remove the journal info block %s (%s)\n",
                                jbuf, strerror(errno));
        }

        printf("Journaling disabled on %s mounted at %s.\n", sfs.f_mntfromname, volname);

        return 0;
}




int
get_journal_info(char *devname, struct JournalInfoBlock *jib)
{
        int fd = -1, ret = 0;
        char *buff = NULL, *buff2 = NULL;
        u_int64_t disksize;
        u_int64_t blkcnt;
        u_int32_t blksize;
        daddr_t   mdb_offset;
        HFSMasterDirectoryBlock *mdbp;
        HFSPlusVolumeHeader *vhp;
        off_t embeddedOffset, pos;
        struct JournalInfoBlock *myjib;

        fd = open(devname, O_RDONLY);
        if (fd < 0) {
                printf("can't open: %s (%s)\n", devname, strerror(errno));
                ret = -5;
                goto out;
        }

        /* Get the real physical block size. */
        if (ioctl(fd, DKIOCGETBLOCKSIZE, (caddr_t)&blksize) != 0) {
                printf("can't get the device block size (%s). assuming 512\n", strerror(errno));
                blksize = 512;
                ret = -1;
                goto out;
        }

        /* Get the number of physical blocks. */
        if (ioctl(fd, DKIOCGETBLOCKCOUNT, (caddr_t)&blkcnt)) {
                struct stat st;
                printf("failed to get block count. trying stat().\n");
                if (fstat(fd, &st) != 0) {
                        ret = -1;
                        goto out;
                }

                blkcnt = st.st_size / blksize;
        }

        /* Compute an accurate disk size */
        disksize = blkcnt * (u_int64_t)blksize;

        /*
         * There are only 31 bits worth of block count in
         * the buffer cache.  So for large volumes a 4K
         * physical block size is needed.
         */
        if (blksize == 512 && blkcnt > (u_int64_t)0x000000007fffffff) {
                blksize = 4096;
        }

        /*
         * At this point:
         *   blksize has our prefered physical block size
         *   blkcnt has the total number of physical blocks
         */

        buff  = (char *)malloc(blksize);
        buff2 = (char *)malloc(blksize);
        
        if (pread(fd, buff, blksize, HFS_PRI_SECTOR(blksize)*blksize) != blksize) {
                printf("failed to read volume header @ offset %d (%s)\n",
                       HFS_PRI_SECTOR(blksize), strerror(errno));
                ret = -1;
                goto out;
        }

        mdbp = (HFSMasterDirectoryBlock *)(buff + HFS_PRI_OFFSET(blksize));

        if (   (SWAP_BE16(mdbp->drSigWord) != kHFSSigWord)
                        && (SWAP_BE16(mdbp->drSigWord) != kHFSPlusSigWord)
                        && (SWAP_BE16(mdbp->drSigWord) != kHFSXSigWord)) {
                ret = -1;
                printf("get_journal_info: invalid volume signature\n");
                goto out;
        }

        mdbp->drSigWord = SWAP_BE16(mdbp->drSigWord);
        mdbp->drEmbedSigWord = SWAP_BE16(mdbp->drEmbedSigWord);
        mdbp->drAlBlSt = SWAP_BE16(mdbp->drAlBlSt);
        mdbp->drEmbedExtent.startBlock = SWAP_BE16(mdbp->drEmbedExtent.startBlock);
        mdbp->drAlBlkSiz = SWAP_BE32(mdbp->drAlBlkSiz);
        mdbp->drEmbedExtent.blockCount = SWAP_BE16(mdbp->drEmbedExtent.blockCount);


        if ((mdbp->drSigWord == kHFSSigWord) && (mdbp->drEmbedSigWord != kHFSPlusSigWord)) {
                // normal hfs can not ever be journaled
                goto out;
        } 
        
        /* Get the embedded Volume Header */
        if (mdbp->drEmbedSigWord == kHFSPlusSigWord) {
                embeddedOffset = mdbp->drAlBlSt * 512;
                embeddedOffset += (u_int64_t)mdbp->drEmbedExtent.startBlock *
                        (u_int64_t)mdbp->drAlBlkSiz;

                /*
                 * If the embedded volume doesn't start on a block
                 * boundary, then switch the device to a 512-byte
                 * block size so everything will line up on a block
                 * boundary.
                 */
                if ((embeddedOffset % blksize) != 0) {
                        printf("HFS Mount: embedded volume offset not"
                               " a multiple of physical block size (%d);"
                               " switching to 512\n", blksize);
                
                        blkcnt  *= (blksize / 512);
                        blksize  = 512;
                }

                disksize = (u_int64_t)mdbp->drEmbedExtent.blockCount *
                        (u_int64_t)mdbp->drAlBlkSiz;

                mdb_offset = (embeddedOffset / blksize) + HFS_PRI_SECTOR(blksize);
                if (pread(fd, buff, blksize, mdb_offset * blksize) != blksize) {
                        printf("failed to read the embedded vhp @ offset %d\n", mdb_offset * blksize);
                        ret = -1;
                        goto out;
                }

                vhp = (HFSPlusVolumeHeader*) (buff + HFS_PRI_OFFSET(blksize));

                mdbp = (HFSMasterDirectoryBlock *)vhp;
                if (   (SWAP_BE16(mdbp->drSigWord) != kHFSSigWord)
                                && (SWAP_BE16(mdbp->drSigWord) != kHFSPlusSigWord)
                                && (SWAP_BE16(mdbp->drSigWord) != kHFSXSigWord)) {
                        ret = -1;
                        
                        printf("get_journal_info: invalid embedded volume signature \n");
                        goto out;
                }

        } else /* pure HFS+ */ {
                embeddedOffset = 0;
                vhp = (HFSPlusVolumeHeader*) mdbp;
        }

        if ((SWAP_BE32(vhp->attributes) & kHFSVolumeJournaledMask) == 0) {
                ret = 0;
                goto out;
        }

        //
        // Now read the journal info block... (when calculating the
        // position, make sure to cast to unsigned first, then to
        // off_t so that things don't get sign-extended improperly
        // or truncated).
        //
        pos = (off_t)((off_t)embeddedOffset +
                      (off_t)((unsigned int)SWAP_BE32(vhp->journalInfoBlock))*(off_t)((unsigned int)SWAP_BE32(vhp->blockSize)));

        if (pread(fd, buff2, blksize, pos) != blksize) {
                printf("failed to read the journal info block (%s).\n", strerror(errno));
                ret = -1;
                goto out;
        }

        myjib = (struct JournalInfoBlock *)buff2;
        myjib->flags  = SWAP_BE32(myjib->flags);
        myjib->offset = SWAP_BE64(myjib->offset);
        myjib->size   = SWAP_BE64(myjib->size);
        
        memcpy(jib, myjib, sizeof(*myjib));
        
        ret = 1;

out:
        if (buff)
                free(buff);
        if (buff2)
                free(buff2);
        if (fd >= 0) 
                close(fd);

        return ret;
}


int
DoGetJournalInfo(char *volname)
{
    struct statfs sfs;
    struct hfs_journal_info jinfo;
        
    if (strncmp(volname, "/dev/", 5) == 0 || strncmp(volname, "disk", 4) == 0 || strncmp(volname, "rdisk", 5) == 0) {
            struct JournalInfoBlock jib;
            int ret;
            char fulldevname[256];

            if (strncmp(volname, "disk", 4) == 0 || strncmp(volname, "rdisk", 5) == 0) {
                    snprintf(fulldevname, sizeof(fulldevname), "/dev/%s", volname);
                    volname = &fulldevname[0];
            }
            
            // try the name as a device name...
            ret = get_journal_info(volname, &jib);
            if (ret == 0) {
                    printf("Volume %s is not journaled.\n", volname);
                    return 0;
            } else if (ret < 0) {
                    printf("Volume %s does not appear to be an HFS+ volume.\n", volname);
                    return 10;
            } else {
                if (jib.flags & kJIJournalInFSMask) {
                        printf("%s : journal size %lld k at offset 0x%llx\n", volname, jib.size/1024, jib.offset);
                } else {
                        printf("%s: external journal stored on partition with uuid %s on machine w/serial number %s\n",
                               volname, jib.ext_jnl_uuid, jib.machine_serial_num);
                }

                return 0;
            }

    }

    if (statfs(volname, &sfs) != 0) {
            fprintf(stderr, "Unable to get fs info for %s\n", volname);
            return 10;
    }

    if ((sfs.f_flags & MNT_JOURNALED) == 0) {
        fprintf(stderr, "Volume %s is not journaled.\n", volname);
        return 1;
    }

    if (fsctl(volname, HFSIOC_GET_JOURNAL_INFO,  &jinfo, 0) != 0) {
        fprintf(stderr, "Failed to get journal info for volume %s (%s)\n",
                volname, strerror(errno));
        return 20;
    }

    if (jinfo.jstart == 0) {
            char rawdev[256];

            snprintf(rawdev, sizeof(rawdev), "/dev/r%s", &sfs.f_mntfromname[5]);

            // it's an external journal so get the info the
            // other way.
            return DoGetJournalInfo(&rawdev[0]);
    }

    if (jinfo.jsize == 0) {
        printf("%s : not journaled.\n", volname);
    } else {
        printf("%s : journal size %lld k at offset 0x%llx\n", volname, jinfo.jsize/1024, jinfo.jstart);
    }

    return 0;
}


int
RawDisableJournaling(char *devname)
{
    int fd = -1, ret = 0;
    char *buff = NULL, rawdev[256], unrawdev[256];
    u_int64_t disksize;
    u_int64_t blkcnt;
    u_int32_t blksize;
    daddr_t   mdb_offset;
    HFSMasterDirectoryBlock *mdbp;
    HFSPlusVolumeHeader *vhp;
    off_t embeddedOffset, hdr_offset;
    struct stat   st;
    struct statfs *fsinfo;
        
        // assume that the name provided is a raw device name
        strlcpy(rawdev, devname, sizeof(rawdev));

restart:
        if (stat(rawdev, &st) != 0) {
                fprintf(stderr, "Could not access %s (%s)\n", devname, strerror(errno));
                ret = -1;
                goto out;
        }
        
        if (S_ISCHR(st.st_mode) == 0) {
                if (S_ISBLK(st.st_mode)) {
                        // this is a block device, convert the name to 
                        // raw character device and try again
                        snprintf(rawdev, sizeof(rawdev), "/dev/r%s", devname + 5);
                        goto restart;
                } else {
                        // probably it is a mount point 
                        return DoUnJournal(devname);
                }
        } else {
                // convert the character raw device name to 
                // block device name to compare with getmntinfo output
                snprintf(unrawdev, sizeof(unrawdev), "/dev/%s", rawdev + 6);
        }
        
        // make sure that the file system on the device node is not mounted
        ret = getmntinfo(&fsinfo, MNT_NOWAIT);
        if (ret == 0) {
                fprintf (stderr, "Error getting list of mounted filesystems\n"); 
                ret = -1;
                goto out;
        }
        
        while (ret--) {
                // the file system on this device node is currently mounted
                if (strcmp(unrawdev, fsinfo[ret].f_mntfromname) == 0) {
                        return DoUnJournal(fsinfo[ret].f_mntonname);
                }
        }

    fd = open(rawdev, O_RDWR);
    if (fd < 0) {
        fprintf(stderr, "can't open: %s (%s)\n", devname, strerror(errno));
        ret = -1;
        goto out;
    }

    /* Get the real physical block size. */
    if (ioctl(fd, DKIOCGETBLOCKSIZE, (caddr_t)&blksize) != 0) {
        fprintf(stderr, "can't get the device block size (%s). assuming 512\n", strerror(errno));
        blksize = 512;
        ret = -1;
        goto out;
    }

    /* Get the number of physical blocks. */
    if (ioctl(fd, DKIOCGETBLOCKCOUNT, (caddr_t)&blkcnt)) {
        struct stat st;

        if (fstat(fd, &st) != 0) {
            ret = -1;
            goto out;
        }

        blkcnt = st.st_size / blksize;
    }

    /* Compute an accurate disk size */
    disksize = blkcnt * (u_int64_t)blksize;

    /*
     * There are only 31 bits worth of block count in
     * the buffer cache.  So for large volumes a 4K
     * physical block size is needed.
     */
    if (blksize == 512 && blkcnt > (u_int64_t)0x000000007fffffff) {
        blksize = 4096;
    }

    /*
     * At this point:
     *   blksize has our prefered physical block size
     *   blkcnt has the total number of physical blocks
     */

    buff  = (char *)malloc(blksize);
        
    hdr_offset = HFS_PRI_SECTOR(blksize)*blksize;
    if (pread(fd, buff, blksize, hdr_offset) != blksize) {
                fprintf(stderr, "RawDisableJournaling: failed to read volume header @ offset %lld (%s)\n",
                                hdr_offset, strerror(errno));
                ret = -1;
                goto out;
    }

        mdbp = (HFSMasterDirectoryBlock *)(buff + HFS_PRI_OFFSET(blksize));
        if (   (SWAP_BE16(mdbp->drSigWord) != kHFSSigWord)
                && (SWAP_BE16(mdbp->drSigWord) != kHFSPlusSigWord)
                && (SWAP_BE16(mdbp->drSigWord) != kHFSXSigWord)) {
                ret = -1;
                printf("RawDisableJournaling: Invalid Volume Signature \n");
                goto out;
        }
        
    if ((SWAP_BE16(mdbp->drSigWord) == kHFSSigWord) && (SWAP_BE16(mdbp->drEmbedSigWord) != kHFSPlusSigWord)) {
        // normal hfs can not ever be journaled
        fprintf(stderr, "disable_journaling: volume is only regular HFS, not HFS+\n");
        goto out;
    } 
        
    /* Get the embedded Volume Header */
    if (SWAP_BE16(mdbp->drEmbedSigWord) == kHFSPlusSigWord) {
                embeddedOffset = SWAP_BE16(mdbp->drAlBlSt) * 512;
                embeddedOffset += (u_int64_t)SWAP_BE16(mdbp->drEmbedExtent.startBlock) * (u_int64_t)SWAP_BE32(mdbp->drAlBlkSiz);
                
                /*
                 * If the embedded volume doesn't start on a block
                 * boundary, then switch the device to a 512-byte
                 * block size so everything will line up on a block
                 * boundary.
                 */
                if ((embeddedOffset % blksize) != 0) {
                        fprintf(stderr, "HFS Mount: embedded volume offset not"
                                        " a multiple of physical block size (%d);"
                                        " switching to 512\n", blksize);
                        
                        blkcnt  *= (blksize / 512);
                        blksize  = 512;
                }
                
                disksize = (u_int64_t)SWAP_BE16(mdbp->drEmbedExtent.blockCount) * (u_int64_t)SWAP_BE32(mdbp->drAlBlkSiz);
                
                mdb_offset = (embeddedOffset / blksize) + HFS_PRI_SECTOR(blksize);
                hdr_offset = mdb_offset * blksize;
                if (pread(fd, buff, blksize, hdr_offset) != blksize) {
                        fprintf(stderr, "failed to read the embedded vhp @ offset %d\n", mdb_offset * blksize);
                        ret = -1;
                        goto out;
                }
                
                vhp = (HFSPlusVolumeHeader*) (buff + HFS_PRI_OFFSET(blksize));
                
                mdbp = (HFSMasterDirectoryBlock *)vhp;
                if (   (SWAP_BE16(mdbp->drSigWord) != kHFSSigWord)
                        && (SWAP_BE16(mdbp->drSigWord) != kHFSPlusSigWord)
                        && (SWAP_BE16(mdbp->drSigWord) != kHFSXSigWord)) {
                        ret = -1;
                        
                        printf("RawDisableJournaling: invalid embedded volume signature \n");
                        goto out;
                }
                
    } else /* pure HFS+ */ {
                embeddedOffset = 0;
                vhp = (HFSPlusVolumeHeader*) mdbp;
    }


    if ((SWAP_BE32(vhp->attributes) & kHFSVolumeJournaledMask) != 0) {
                unsigned int tmp = SWAP_BE32(vhp->attributes);
                
                tmp &= ~kHFSVolumeJournaledMask;
                vhp->attributes = SWAP_BE32(tmp);
                if ((tmp = pwrite(fd, buff, blksize, hdr_offset)) != blksize) {
                        fprintf(stderr, "Update of super-block on %s failed! (%d != %d, %s)\n",
                                        devname, tmp, blksize, strerror(errno));
                } else {
                        fprintf(stderr, "Turned off the journaling bit for %s\n", devname);
                }
    } else {
                fprintf(stderr, "disable_journaling: %s is not journaled.\n", devname);
    }
        
        
  out:
    if (buff)
        free(buff);
    if (fd >= 0) 
        close(fd);

    return ret;
}



int
SetJournalInFSState(const char *devname, int journal_in_fs)
{
        int fd = -1, ret = 0;
        char *buff = NULL, *buff2 = NULL;
        u_int64_t blkcnt;
        u_int32_t blksize;
        daddr_t   mdb_offset;
        HFSMasterDirectoryBlock *mdbp;
        HFSPlusVolumeHeader *vhp;
        off_t embeddedOffset, pos;
        struct JournalInfoBlock *myjib;

        fd = open(devname, O_RDWR);
        if (fd < 0) {
                printf("can't open: %s (%s)\n", devname, strerror(errno));
                ret = -1;
                goto out;
        }

        /* Get the real physical block size. */
        if (ioctl(fd, DKIOCGETBLOCKSIZE, (caddr_t)&blksize) != 0) {
                printf("can't get the device block size (%s). assuming 512\n", strerror(errno));
                blksize = 512;
                ret = -1;
                goto out;
        }

        /* Get the number of physical blocks. */
        if (ioctl(fd, DKIOCGETBLOCKCOUNT, (caddr_t)&blkcnt)) {
                struct stat st;
                printf("failed to get block count. trying stat().\n");
                if (fstat(fd, &st) != 0) {
                        ret = -1;
                        goto out;
                }

                blkcnt = st.st_size / blksize;
        }

        /*
         * There used to only be 31 bits worth of block count in
         * the buffer cache.  So for large volumes a 4K
         * physical block size is needed.
         */
        if (blksize == 512 && blkcnt > (u_int64_t)0x000000007fffffff) {
                blksize = 4096;
        }

        /*
         * At this point:
         *   blksize has our prefered physical block size
         *   blkcnt has the total number of physical blocks
         */

        buff  = (char *)malloc(blksize);
        buff2 = (char *)malloc(blksize);
        
        if (pread(fd, buff, blksize, HFS_PRI_SECTOR(blksize)*blksize) != blksize) {
                printf("failed to read volume header @ offset %d (%s)\n",
                           HFS_PRI_SECTOR(blksize), strerror(errno));
                ret = -1;
                goto out;
        }

        mdbp = (HFSMasterDirectoryBlock *)(buff + HFS_PRI_OFFSET(blksize));


        if (   (SWAP_BE16(mdbp->drSigWord) != kHFSSigWord)
                        && (SWAP_BE16(mdbp->drSigWord) != kHFSPlusSigWord)
                        && (SWAP_BE16(mdbp->drSigWord) != kHFSXSigWord)) {
                ret = -1;
                printf ("SetJournalInFSState: Invalid Volume Signature \n");
                goto out;
        }

        if ((SWAP_BE16(mdbp->drSigWord) == kHFSSigWord) && (SWAP_BE16(mdbp->drEmbedSigWord) != kHFSPlusSigWord)) {
                // normal hfs can not ever be journaled
                goto out;
        } 
        
        /* Get the embedded Volume Header */
        if (SWAP_BE16(mdbp->drEmbedSigWord) == kHFSPlusSigWord) {
            embeddedOffset = SWAP_BE16(mdbp->drAlBlSt) * 512;
            embeddedOffset += (u_int64_t)SWAP_BE16(mdbp->drEmbedExtent.startBlock) *
                              (u_int64_t)SWAP_BE32(mdbp->drAlBlkSiz);

            /*
             * If the embedded volume doesn't start on a block
             * boundary, then switch the device to a 512-byte
             * block size so everything will line up on a block
             * boundary.
             */
            if ((embeddedOffset % blksize) != 0) {
                printf("HFS Mount: embedded volume offset not"
                       " a multiple of physical block size (%d);"
                       " switching to 512\n", blksize);
                
                blkcnt  *= (blksize / 512);
                blksize  = 512;
            }

            mdb_offset = (embeddedOffset / blksize) + HFS_PRI_SECTOR(blksize);
            if (pread(fd, buff, blksize, mdb_offset * blksize) != blksize) {
                printf("failed to read the embedded vhp @ offset %d\n", mdb_offset * blksize);
                ret = -1;
                goto out;
            }

            vhp = (HFSPlusVolumeHeader*) (buff + HFS_PRI_OFFSET(blksize));
                
                mdbp = (HFSMasterDirectoryBlock *)(vhp);
                if (   (SWAP_BE16(mdbp->drSigWord) != kHFSSigWord)
                        && (SWAP_BE16(mdbp->drSigWord) != kHFSPlusSigWord)
                        && (SWAP_BE16(mdbp->drSigWord) != kHFSXSigWord)) {
                        ret = -1;
                        printf("SetJournalInFSState: Invalid Embedded Volume Signature \n");
                        goto out;
                }
                
                
        } else /* pure HFS+ */ {
            embeddedOffset = 0;
            vhp = (HFSPlusVolumeHeader*) mdbp;
        }

        //printf("vol header attributes: 0x%x\n", SWAP_BE32(vhp->attributes));
        if ((SWAP_BE32(vhp->attributes) & kHFSVolumeJournaledMask) == 0) {
            ret = 0;
            goto out;
        }

        //
        // Now read the journal info block... (when calculating the
        // position, make sure to cast to unsigned first, then to
        // off_t so that things don't get sign-extended improperly
        // or truncated).
        //
        pos = (off_t)((off_t)embeddedOffset +
                      (off_t)((unsigned int )SWAP_BE32(vhp->journalInfoBlock))*(off_t)((unsigned int)SWAP_BE32(vhp->blockSize)));

        if (pread(fd, buff2, blksize, pos) != blksize) {
            printf("failed to read the journal info block (%s).\n", strerror(errno));
            ret = -1;
            goto out;
        }

        myjib = (struct JournalInfoBlock *)buff2;

        // swap this to host native format so we can diddle with the bits
        myjib->flags  = SWAP_BE32(myjib->flags);
        
        if (journal_in_fs) {
                myjib->flags |= kJIJournalInFSMask;
        } else {
                myjib->flags &= ~kJIJournalInFSMask;
        }
        myjib->flags |= kJIJournalNeedInitMask;

        // and now swap back before writing it out
        myjib->flags  = SWAP_BE32(myjib->flags);
        
        if (pwrite(fd, buff2, blksize, pos) != blksize) {
            printf("failed to re-write the journal info block (%s).\n", strerror(errno));
            ret = -1;
            goto out;
        }

        ret = 0;

  out:
        if (buff)
                free(buff);
        if (buff2)
                free(buff2);
        if (fd >= 0) 
                close(fd);

        return ret;
}