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libntfs/source/device.c

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/**
* 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;
}
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