usbloadergx/source/libntfs/device.c

/**
 * device.c - Low level device io functions. Originated from the Linux-NTFS project.
 *
 * Copyright (c) 2004-2006 Anton Altaparmakov
 * Copyright (c) 2004-2006 Szabolcs Szakacsits
 *
 * This program/include file is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program/include file is distributed in the hope that it will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program (in the main directory of the NTFS-3G
 * distribution in the file COPYING); if not, write to the Free Software
 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_STDIO_H
#include <stdio.h>
#endif
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif
#ifdef HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif
#ifdef HAVE_SYS_MOUNT_H
#include <sys/mount.h>
#endif
#ifdef HAVE_LINUX_FD_H
#include <linux/fd.h>
#endif
#ifdef HAVE_LINUX_HDREG_H
#include <linux/hdreg.h>
#endif

#include "types.h"
#include "mst.h"
#include "debug.h"
#include "device.h"
#include "logging.h"
#include "misc.h"

#if defined(linux) && defined(_IO) && !defined(BLKGETSIZE)
#define BLKGETSIZE  _IO(0x12,96)  /* Get device size in 512-byte blocks. */
#endif
#if defined(linux) && defined(_IOR) && !defined(BLKGETSIZE64)
#define BLKGETSIZE64    _IOR(0x12,114,size_t)   /* Get device size in bytes. */
#endif
#if defined(linux) && !defined(HDIO_GETGEO)
#define HDIO_GETGEO 0x0301  /* Get device geometry. */
#endif
#if defined(linux) && defined(_IO) && !defined(BLKSSZGET)
#   define BLKSSZGET _IO(0x12,104) /* Get device sector size in bytes. */
#endif
#if defined(linux) && defined(_IO) && !defined(BLKBSZSET)
#   define BLKBSZSET _IOW(0x12,113,size_t) /* Set device block size in bytes. */
#endif

/**
 * ntfs_device_alloc - allocate an ntfs device structure and pre-initialize it
 * @name:   name of the device (must be present)
 * @state:  initial device state (usually zero)
 * @dops:   ntfs device operations to use with the device (must be present)
 * @priv_data:  pointer to private data (optional)
 *
 * Allocate an ntfs device structure and pre-initialize it with the user-
 * specified device operations @dops, device state @state, device name @name,
 * and optional private data @priv_data.
 *
 * Note, @name is copied and can hence be freed after this functions returns.
 *
 * On success return a pointer to the allocated ntfs device structure and on
 * error return NULL with errno set to the error code returned by ntfs_malloc().
 */
struct ntfs_device *ntfs_device_alloc( const char *name, const long state,
                                       struct ntfs_device_operations *dops, void *priv_data )
{
    struct ntfs_device *dev;

    if ( !name )
    {
        errno = EINVAL;
        return NULL;
    }

    dev = ntfs_malloc( sizeof( struct ntfs_device ) );
    if ( dev )
    {
        if ( !( dev->d_name = strdup( name ) ) )
        {
            int eo = errno;
            free( dev );
            errno = eo;
            return NULL;
        }
        dev->d_ops = dops;
        dev->d_state = state;
        dev->d_private = priv_data;
    }
    return dev;
}

/**
 * ntfs_device_free - free an ntfs device structure
 * @dev:    ntfs device structure to free
 *
 * Free the ntfs device structure @dev.
 *
 * Return 0 on success or -1 on error with errno set to the error code. The
 * following error codes are defined:
 *  EINVAL      Invalid pointer @dev.
 *  EBUSY       Device is still open. Close it before freeing it!
 */
int ntfs_device_free( struct ntfs_device *dev )
{
    if ( !dev )
    {
        errno = EINVAL;
        return -1;
    }
    if ( NDevOpen( dev ) )
    {
        errno = EBUSY;
        return -1;
    }
    free( dev->d_name );
    free( dev );
    return 0;
}

/**
 * ntfs_pread - positioned read from disk
 * @dev:    device to read from
 * @pos:    position in device to read from
 * @count:  number of bytes to read
 * @b:      output data buffer
 *
 * This function will read @count bytes from device @dev at position @pos into
 * the data buffer @b.
 *
 * On success, return the number of successfully read bytes. If this number is
 * lower than @count this means that we have either reached end of file or
 * encountered an error during the read so that the read is partial. 0 means
 * end of file or nothing to read (@count is 0).
 *
 * On error and nothing has been read, return -1 with errno set appropriately
 * to the return code of either seek, read, or set to EINVAL in case of
 * invalid arguments.
 */
s64 ntfs_pread( struct ntfs_device *dev, const s64 pos, s64 count, void *b )
{
    s64 br, total;
    struct ntfs_device_operations *dops;

    ntfs_log_trace( "pos %lld, count %lld\n", ( long long )pos, ( long long )count );

    if ( !b || count < 0 || pos < 0 )
    {
        errno = EINVAL;
        return -1;
    }
    if ( !count )
        return 0;

    dops = dev->d_ops;

    for ( total = 0; count; count -= br, total += br )
    {
        br = dops->pread( dev, ( char* )b + total, count, pos + total );
        /* If everything ok, continue. */
        if ( br > 0 )
            continue;
        /* If EOF or error return number of bytes read. */
        if ( !br || total )
            return total;
        /* Nothing read and error, return error status. */
        return br;
    }
    /* Finally, return the number of bytes read. */
    return total;
}

/**
 * ntfs_pwrite - positioned write to disk
 * @dev:    device to write to
 * @pos:    position in file descriptor to write to
 * @count:  number of bytes to write
 * @b:      data buffer to write to disk
 *
 * This function will write @count bytes from data buffer @b to the device @dev
 * at position @pos.
 *
 * On success, return the number of successfully written bytes. If this number
 * is lower than @count this means that the write has been interrupted in
 * flight or that an error was encountered during the write so that the write
 * is partial. 0 means nothing was written (also return 0 when @count is 0).
 *
 * On error and nothing has been written, return -1 with errno set
 * appropriately to the return code of either seek, write, or set
 * to EINVAL in case of invalid arguments.
 */
s64 ntfs_pwrite( struct ntfs_device *dev, const s64 pos, s64 count,
                 const void *b )
{
    s64 written, total, ret = -1;
    struct ntfs_device_operations *dops;

    ntfs_log_trace( "pos %lld, count %lld\n", ( long long )pos, ( long long )count );

    if ( !b || count < 0 || pos < 0 )
    {
        errno = EINVAL;
        goto out;
    }
    if ( !count )
        return 0;
    if ( NDevReadOnly( dev ) )
    {
        errno = EROFS;
        goto out;
    }

    dops = dev->d_ops;

    NDevSetDirty( dev );
    for ( total = 0; count; count -= written, total += written )
    {
        written = dops->pwrite( dev, ( const char* )b + total, count,
                                pos + total );
        /* If everything ok, continue. */
        if ( written > 0 )
            continue;
        /*
         * If nothing written or error return number of bytes written.
         */
        if ( !written || total )
            break;
        /* Nothing written and error, return error status. */
        total = written;
        break;
    }
    ret = total;
out:
    return ret;
}

/**
 * ntfs_mst_pread - multi sector transfer (mst) positioned read
 * @dev:    device to read from
 * @pos:    position in file descriptor to read from
 * @count:  number of blocks to read
 * @bksize: size of each block that needs mst deprotecting
 * @b:      output data buffer
 *
 * Multi sector transfer (mst) positioned read. This function will read @count
 * blocks of size @bksize bytes each from device @dev at position @pos into the
 * the data buffer @b.
 *
 * On success, return the number of successfully read blocks. If this number is
 * lower than @count this means that we have reached end of file, that the read
 * was interrupted, or that an error was encountered during the read so that
 * the read is partial. 0 means end of file or nothing was read (also return 0
 * when @count or @bksize are 0).
 *
 * On error and nothing was read, return -1 with errno set appropriately to the
 * return code of either seek, read, or set to EINVAL in case of invalid
 * arguments.
 *
 * NOTE: If an incomplete multi sector transfer has been detected the magic
 * will have been changed to magic_BAAD but no error will be returned. Thus it
 * is possible that we return count blocks as being read but that any number
 * (between zero and count!) of these blocks is actually subject to a multi
 * sector transfer error. This should be detected by the caller by checking for
 * the magic being "BAAD".
 */
s64 ntfs_mst_pread( struct ntfs_device *dev, const s64 pos, s64 count,
                    const u32 bksize, void *b )
{
    s64 br, i;

    if ( bksize & ( bksize - 1 ) || bksize % NTFS_BLOCK_SIZE )
    {
        errno = EINVAL;
        return -1;
    }
    /* Do the read. */
    br = ntfs_pread( dev, pos, count * bksize, b );
    if ( br < 0 )
        return br;
    /*
     * Apply fixups to successfully read data, disregarding any errors
     * returned from the MST fixup function. This is because we want to
     * fixup everything possible and we rely on the fact that the "BAAD"
     * magic will be detected later on.
     */
    count = br / bksize;
    for ( i = 0; i < count; ++i )
        ntfs_mst_post_read_fixup( ( NTFS_RECORD* )
                                  ( ( u8* )b + i * bksize ), bksize );
    /* Finally, return the number of complete blocks read. */
    return count;
}

/**
 * ntfs_mst_pwrite - multi sector transfer (mst) positioned write
 * @dev:    device to write to
 * @pos:    position in file descriptor to write to
 * @count:  number of blocks to write
 * @bksize: size of each block that needs mst protecting
 * @b:      data buffer to write to disk
 *
 * Multi sector transfer (mst) positioned write. This function will write
 * @count blocks of size @bksize bytes each from data buffer @b to the device
 * @dev at position @pos.
 *
 * On success, return the number of successfully written blocks. If this number
 * is lower than @count this means that the write has been interrupted or that
 * an error was encountered during the write so that the write is partial. 0
 * means nothing was written (also return 0 when @count or @bksize are 0).
 *
 * On error and nothing has been written, return -1 with errno set
 * appropriately to the return code of either seek, write, or set
 * to EINVAL in case of invalid arguments.
 *
 * NOTE: We mst protect the data, write it, then mst deprotect it using a quick
 * deprotect algorithm (no checking). This saves us from making a copy before
 * the write and at the same time causes the usn to be incremented in the
 * buffer. This conceptually fits in better with the idea that cached data is
 * always deprotected and protection is performed when the data is actually
 * going to hit the disk and the cache is immediately deprotected again
 * simulating an mst read on the written data. This way cache coherency is
 * achieved.
 */
s64 ntfs_mst_pwrite( struct ntfs_device *dev, const s64 pos, s64 count,
                     const u32 bksize, void *b )
{
    s64 written, i;

    if ( count < 0 || bksize % NTFS_BLOCK_SIZE )
    {
        errno = EINVAL;
        return -1;
    }
    if ( !count )
        return 0;
    /* Prepare data for writing. */
    for ( i = 0; i < count; ++i )
    {
        int err;

        err = ntfs_mst_pre_write_fixup( ( NTFS_RECORD* )
                                        ( ( u8* )b + i * bksize ), bksize );
        if ( err < 0 )
        {
            /* Abort write at this position. */
            if ( !i )
                return err;
            count = i;
            break;
        }
    }
    /* Write the prepared data. */
    written = ntfs_pwrite( dev, pos, count * bksize, b );
    /* Quickly deprotect the data again. */
    for ( i = 0; i < count; ++i )
        ntfs_mst_post_write_fixup( ( NTFS_RECORD* )( ( u8* )b + i * bksize ) );
    if ( written <= 0 )
        return written;
    /* Finally, return the number of complete blocks written. */
    return written / bksize;
}

/**
 * ntfs_cluster_read - read ntfs clusters
 * @vol:    volume to read from
 * @lcn:    starting logical cluster number
 * @count:  number of clusters to read
 * @b:      output data buffer
 *
 * Read @count ntfs clusters starting at logical cluster number @lcn from
 * volume @vol into buffer @b. Return number of clusters read or -1 on error,
 * with errno set to the error code.
 */
s64 ntfs_cluster_read( const ntfs_volume *vol, const s64 lcn, const s64 count,
                       void *b )
{
    s64 br;

    if ( !vol || lcn < 0 || count < 0 )
    {
        errno = EINVAL;
        return -1;
    }
    if ( vol->nr_clusters < lcn + count )
    {
        errno = ESPIPE;
        ntfs_log_perror( "Trying to read outside of volume "
                         "(%lld < %lld)", ( long long )vol->nr_clusters,
                         ( long long )lcn + count );
        return -1;
    }
    br = ntfs_pread( vol->dev, lcn << vol->cluster_size_bits,
                     count << vol->cluster_size_bits, b );
    if ( br < 0 )
    {
        ntfs_log_perror( "Error reading cluster(s)" );
        return br;
    }
    return br >> vol->cluster_size_bits;
}

/**
 * ntfs_cluster_write - write ntfs clusters
 * @vol:    volume to write to
 * @lcn:    starting logical cluster number
 * @count:  number of clusters to write
 * @b:      data buffer to write to disk
 *
 * Write @count ntfs clusters starting at logical cluster number @lcn from
 * buffer @b to volume @vol. Return the number of clusters written or -1 on
 * error, with errno set to the error code.
 */
s64 ntfs_cluster_write( const ntfs_volume *vol, const s64 lcn,
                        const s64 count, const void *b )
{
    s64 bw;

    if ( !vol || lcn < 0 || count < 0 )
    {
        errno = EINVAL;
        return -1;
    }
    if ( vol->nr_clusters < lcn + count )
    {
        errno = ESPIPE;
        ntfs_log_perror( "Trying to write outside of volume "
                         "(%lld < %lld)", ( long long )vol->nr_clusters,
                         ( long long )lcn + count );
        return -1;
    }
    if ( !NVolReadOnly( vol ) )
        bw = ntfs_pwrite( vol->dev, lcn << vol->cluster_size_bits,
                          count << vol->cluster_size_bits, b );
    else
        bw = count << vol->cluster_size_bits;
    if ( bw < 0 )
    {
        ntfs_log_perror( "Error writing cluster(s)" );
        return bw;
    }
    return bw >> vol->cluster_size_bits;
}

/**
 * ntfs_device_offset_valid - test if a device offset is valid
 * @dev:    open device
 * @ofs:    offset to test for validity
 *
 * Test if the offset @ofs is an existing location on the device described
 * by the open device structure @dev.
 *
 * Return 0 if it is valid and -1 if it is not valid.
 */
static int ntfs_device_offset_valid( struct ntfs_device *dev, s64 ofs )
{
    char ch;

    if ( dev->d_ops->seek( dev, ofs, SEEK_SET ) >= 0 &&
            dev->d_ops->read( dev, &ch, 1 ) == 1 )
        return 0;
    return -1;
}

/**
 * ntfs_device_size_get - return the size of a device in blocks
 * @dev:    open device
 * @block_size: block size in bytes in which to return the result
 *
 * Return the number of @block_size sized blocks in the device described by the
 * open device @dev.
 *
 * Adapted from e2fsutils-1.19, Copyright (C) 1995 Theodore Ts'o.
 *
 * On error return -1 with errno set to the error code.
 */
s64 ntfs_device_size_get( struct ntfs_device *dev, int block_size )
{
    s64 high, low;

    if ( !dev || block_size <= 0 || ( block_size - 1 ) & block_size )
    {
        errno = EINVAL;
        return -1;
    }
#ifdef BLKGETSIZE64
    {   u64 size;

        if ( dev->d_ops->ioctl( dev, BLKGETSIZE64, &size ) >= 0 )
        {
            ntfs_log_debug( "BLKGETSIZE64 nr bytes = %llu (0x%llx)\n",
                            ( unsigned long long )size,
                            ( unsigned long long )size );
            return ( s64 )size / block_size;
        }
    }
#endif
#ifdef BLKGETSIZE
    {   unsigned long size;

        if ( dev->d_ops->ioctl( dev, BLKGETSIZE, &size ) >= 0 )
        {
            ntfs_log_debug( "BLKGETSIZE nr 512 byte blocks = %lu (0x%lx)\n",
                            size, size );
            return ( s64 )size * 512 / block_size;
        }
    }
#endif
#ifdef FDGETPRM
    {       struct floppy_struct this_floppy;

        if ( dev->d_ops->ioctl( dev, FDGETPRM, &this_floppy ) >= 0 )
        {
            ntfs_log_debug( "FDGETPRM nr 512 byte blocks = %lu (0x%lx)\n",
                            ( unsigned long )this_floppy.size,
                            ( unsigned long )this_floppy.size );
            return ( s64 )this_floppy.size * 512 / block_size;
        }
    }
#endif
    /*
     * We couldn't figure it out by using a specialized ioctl,
     * so do binary search to find the size of the device.
     */
    low = 0LL;
    for ( high = 1024LL; !ntfs_device_offset_valid( dev, high ); high <<= 1 )
        low = high;
    while ( low < high - 1LL )
    {
        const s64 mid = ( low + high ) / 2;

        if ( !ntfs_device_offset_valid( dev, mid ) )
            low = mid;
        else
            high = mid;
    }
    dev->d_ops->seek( dev, 0LL, SEEK_SET );
    return ( low + 1LL ) / block_size;
}

/**
 * ntfs_device_partition_start_sector_get - get starting sector of a partition
 * @dev:    open device
 *
 * On success, return the starting sector of the partition @dev in the parent
 * block device of @dev.  On error return -1 with errno set to the error code.
 *
 * The following error codes are defined:
 *  EINVAL      Input parameter error
 *  EOPNOTSUPP  System does not support HDIO_GETGEO ioctl
 *  ENOTTY      @dev is a file or a device not supporting HDIO_GETGEO
 */
s64 ntfs_device_partition_start_sector_get( struct ntfs_device *dev )
{
    if ( !dev )
    {
        errno = EINVAL;
        return -1;
    }
#ifdef HDIO_GETGEO
    {   struct hd_geometry geo;

        if ( !dev->d_ops->ioctl( dev, HDIO_GETGEO, &geo ) )
        {
            ntfs_log_debug( "HDIO_GETGEO start_sect = %lu (0x%lx)\n",
                            geo.start, geo.start );
            return geo.start;
        }
    }
#else
    errno = EOPNOTSUPP;
#endif
    return -1;
}

/**
 * ntfs_device_heads_get - get number of heads of device
 * @dev:        open device
 *
 * On success, return the number of heads on the device @dev.  On error return
 * -1 with errno set to the error code.
 *
 * The following error codes are defined:
 *  EINVAL      Input parameter error
 *  EOPNOTSUPP  System does not support HDIO_GETGEO ioctl
 *  ENOTTY      @dev is a file or a device not supporting HDIO_GETGEO
 */
int ntfs_device_heads_get( struct ntfs_device *dev )
{
    if ( !dev )
    {
        errno = EINVAL;
        return -1;
    }
#ifdef HDIO_GETGEO
    {   struct hd_geometry geo;

        if ( !dev->d_ops->ioctl( dev, HDIO_GETGEO, &geo ) )
        {
            ntfs_log_debug( "HDIO_GETGEO heads = %u (0x%x)\n",
                            ( unsigned )geo.heads,
                            ( unsigned )geo.heads );
            return geo.heads;
        }
    }
#else
    errno = EOPNOTSUPP;
#endif
    return -1;
}

/**
 * ntfs_device_sectors_per_track_get - get number of sectors per track of device
 * @dev:        open device
 *
 * On success, return the number of sectors per track on the device @dev.  On
 * error return -1 with errno set to the error code.
 *
 * The following error codes are defined:
 *  EINVAL      Input parameter error
 *  EOPNOTSUPP  System does not support HDIO_GETGEO ioctl
 *  ENOTTY      @dev is a file or a device not supporting HDIO_GETGEO
 */
int ntfs_device_sectors_per_track_get( struct ntfs_device *dev )
{
    if ( !dev )
    {
        errno = EINVAL;
        return -1;
    }
#ifdef HDIO_GETGEO
    {   struct hd_geometry geo;

        if ( !dev->d_ops->ioctl( dev, HDIO_GETGEO, &geo ) )
        {
            ntfs_log_debug( "HDIO_GETGEO sectors_per_track = %u (0x%x)\n",
                            ( unsigned )geo.sectors,
                            ( unsigned )geo.sectors );
            return geo.sectors;
        }
    }
#else
    errno = EOPNOTSUPP;
#endif
    return -1;
}

/**
 * ntfs_device_sector_size_get - get sector size of a device
 * @dev:    open device
 *
 * On success, return the sector size in bytes of the device @dev.
 * On error return -1 with errno set to the error code.
 *
 * The following error codes are defined:
 *  EINVAL      Input parameter error
 *  EOPNOTSUPP  System does not support BLKSSZGET ioctl
 *  ENOTTY      @dev is a file or a device not supporting BLKSSZGET
 */
int ntfs_device_sector_size_get( struct ntfs_device *dev )
{
    if ( !dev )
    {
        errno = EINVAL;
        return -1;
    }
#ifdef BLKSSZGET
    {
        int sect_size = 0;

        if ( !dev->d_ops->ioctl( dev, BLKSSZGET, &sect_size ) )
        {
            ntfs_log_debug( "BLKSSZGET sector size = %d bytes\n",
                            sect_size );
            return sect_size;
        }
    }
#else
    errno = EOPNOTSUPP;
#endif
    return -1;
}

/**
 * ntfs_device_block_size_set - set block size of a device
 * @dev:    open device
 * @block_size: block size to set @dev to
 *
 * On success, return 0.
 * On error return -1 with errno set to the error code.
 *
 * The following error codes are defined:
 *  EINVAL      Input parameter error
 *  EOPNOTSUPP  System does not support BLKBSZSET ioctl
 *  ENOTTY      @dev is a file or a device not supporting BLKBSZSET
 */
int ntfs_device_block_size_set( struct ntfs_device *dev,
                                int block_size __attribute__( ( unused ) ) )
{
    if ( !dev )
    {
        errno = EINVAL;
        return -1;
    }
#ifdef BLKBSZSET
    {
        size_t s_block_size = block_size;
        if ( !dev->d_ops->ioctl( dev, BLKBSZSET, &s_block_size ) )
        {
            ntfs_log_debug( "Used BLKBSZSET to set block size to "
                            "%d bytes.\n", block_size );
            return 0;
        }
        /* If not a block device, pretend it was successful. */
        if ( !NDevBlock( dev ) )
            return 0;
    }
#else
    /* If not a block device, pretend it was successful. */
    if ( !NDevBlock( dev ) )
        return 0;
    errno = EOPNOTSUPP;
#endif
    return -1;
}