mirror of
https://git.code.sf.net/p/ntfs-3g/ntfs-3g.git
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372 lines
8.0 KiB
C
372 lines
8.0 KiB
C
/**
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* unix_io.c - Unix style disk io functions. Originated from the Linux-NTFS project.
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*
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* Copyright (c) 2000-2006 Anton Altaparmakov
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*
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* This program/include file is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as published
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* by the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program/include file is distributed in the hope that it will be
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* useful, but WITHOUT ANY WARRANTY; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program (in the main directory of the NTFS-3G
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* distribution in the file COPYING); if not, write to the Free Software
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* Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#ifdef HAVE_STDLIB_H
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#include <stdlib.h>
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#endif
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#ifdef HAVE_STRING_H
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#include <string.h>
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#endif
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#ifdef HAVE_ERRNO_H
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#include <errno.h>
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#endif
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#ifdef HAVE_STDIO_H
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#include <stdio.h>
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#endif
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#ifdef HAVE_SYS_TYPES_H
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#include <sys/types.h>
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#endif
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#ifdef HAVE_SYS_STAT_H
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#include <sys/stat.h>
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#endif
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#ifdef HAVE_FCNTL_H
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#include <fcntl.h>
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#endif
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#ifdef HAVE_SYS_IOCTL_H
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#include <sys/ioctl.h>
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#endif
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#ifdef HAVE_LINUX_FD_H
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#include <linux/fd.h>
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#endif
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#include "types.h"
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#include "mst.h"
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#include "debug.h"
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#include "device.h"
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#include "logging.h"
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#include "misc.h"
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#define DEV_FD(dev) (*(int *)dev->d_private)
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/* Define to nothing if not present on this system. */
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#ifndef O_EXCL
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# define O_EXCL 0
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#endif
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/**
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* fsync replacement which makes every effort to try to get the data down to
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* disk, using different means for different operating systems. Specifically,
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* it issues the proper fcntl for Mac OS X or does fsync where it is available
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* or as a last resort calls the fsync function. Information on this problem
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* was retrieved from:
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* http://mirror.linux.org.au/pub/linux.conf.au/2007/video/talks/278.pdf
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*/
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static int ntfs_fsync(int fildes)
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{
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int ret = -1;
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#if defined(__APPLE__) || defined(__DARWIN__)
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# ifndef F_FULLFSYNC
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# error "Mac OS X: F_FULLFSYNC is not defined. Either you didn't include fcntl.h or you're using an older, unsupported version of Mac OS X (pre-10.3)."
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# endif
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/*
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* Apple has disabled fsync() for internal disk drives in OS X.
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* To force a synchronization of disk contents, we use a Mac OS X
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* specific fcntl, F_FULLFSYNC.
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*/
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ret = fcntl(fildes, F_FULLFSYNC, NULL);
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if (ret) {
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/*
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* If we are not on a file system that supports this,
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* then fall back to a plain fsync.
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*/
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ret = fsync(fildes);
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}
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#else
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ret = fsync(fildes);
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#endif
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return ret;
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}
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/**
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* ntfs_device_unix_io_open - Open a device and lock it exclusively
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* @dev:
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* @flags:
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*
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* Description...
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*
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* Returns:
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*/
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static int ntfs_device_unix_io_open(struct ntfs_device *dev, int flags)
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{
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struct flock flk;
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struct stat sbuf;
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int err;
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if (NDevOpen(dev)) {
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errno = EBUSY;
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return -1;
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}
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if (stat(dev->d_name, &sbuf)) {
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ntfs_log_perror("Failed to access '%s'", dev->d_name);
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return -1;
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}
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if (S_ISBLK(sbuf.st_mode))
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NDevSetBlock(dev);
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dev->d_private = ntfs_malloc(sizeof(int));
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if (!dev->d_private)
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return -1;
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/*
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* Open file for exclusive access if mounting r/w.
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* Fuseblk takes care about block devices.
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*/
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if (!NDevBlock(dev) && (flags & O_RDWR) == O_RDWR)
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flags |= O_EXCL;
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*(int*)dev->d_private = open(dev->d_name, flags);
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if (*(int*)dev->d_private == -1) {
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err = errno;
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goto err_out;
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}
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if ((flags & O_RDWR) != O_RDWR)
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NDevSetReadOnly(dev);
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memset(&flk, 0, sizeof(flk));
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if (NDevReadOnly(dev))
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flk.l_type = F_RDLCK;
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else
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flk.l_type = F_WRLCK;
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flk.l_whence = SEEK_SET;
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flk.l_start = flk.l_len = 0LL;
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if (fcntl(DEV_FD(dev), F_SETLK, &flk)) {
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err = errno;
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ntfs_log_perror("Failed to %s lock '%s'", NDevReadOnly(dev) ?
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"read" : "write", dev->d_name);
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if (close(DEV_FD(dev)))
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ntfs_log_perror("Failed to close '%s'", dev->d_name);
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goto err_out;
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}
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NDevSetOpen(dev);
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return 0;
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err_out:
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free(dev->d_private);
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dev->d_private = NULL;
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errno = err;
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return -1;
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}
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/**
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* ntfs_device_unix_io_close - Close the device, releasing the lock
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* @dev:
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*
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* Description...
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*
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* Returns:
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*/
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static int ntfs_device_unix_io_close(struct ntfs_device *dev)
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{
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struct flock flk;
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if (!NDevOpen(dev)) {
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errno = EBADF;
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ntfs_log_perror("Device %s is not open", dev->d_name);
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return -1;
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}
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if (NDevDirty(dev))
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if (ntfs_fsync(DEV_FD(dev))) {
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ntfs_log_perror("Failed to fsync device %s", dev->d_name);
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return -1;
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}
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memset(&flk, 0, sizeof(flk));
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flk.l_type = F_UNLCK;
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flk.l_whence = SEEK_SET;
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flk.l_start = flk.l_len = 0LL;
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if (fcntl(DEV_FD(dev), F_SETLK, &flk))
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ntfs_log_perror("Could not unlock %s", dev->d_name);
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if (close(DEV_FD(dev))) {
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ntfs_log_perror("Failed to close device %s", dev->d_name);
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return -1;
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}
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NDevClearOpen(dev);
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free(dev->d_private);
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dev->d_private = NULL;
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return 0;
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}
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/**
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* ntfs_device_unix_io_seek - Seek to a place on the device
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* @dev:
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* @offset:
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* @whence:
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*
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* Description...
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*
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* Returns:
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*/
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static s64 ntfs_device_unix_io_seek(struct ntfs_device *dev, s64 offset,
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int whence)
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{
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return lseek(DEV_FD(dev), offset, whence);
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}
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/**
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* ntfs_device_unix_io_read - Read from the device, from the current location
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* @dev:
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* @buf:
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* @count:
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*
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* Description...
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*
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* Returns:
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*/
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static s64 ntfs_device_unix_io_read(struct ntfs_device *dev, void *buf,
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s64 count)
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{
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return read(DEV_FD(dev), buf, count);
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}
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/**
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* ntfs_device_unix_io_write - Write to the device, at the current location
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* @dev:
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* @buf:
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* @count:
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*
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* Description...
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*
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* Returns:
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*/
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static s64 ntfs_device_unix_io_write(struct ntfs_device *dev, const void *buf,
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s64 count)
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{
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if (NDevReadOnly(dev)) {
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errno = EROFS;
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return -1;
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}
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NDevSetDirty(dev);
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return write(DEV_FD(dev), buf, count);
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}
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/**
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* ntfs_device_unix_io_pread - Perform a positioned read from the device
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* @dev:
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* @buf:
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* @count:
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* @offset:
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*
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* Description...
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*
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* Returns:
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*/
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static s64 ntfs_device_unix_io_pread(struct ntfs_device *dev, void *buf,
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s64 count, s64 offset)
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{
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return pread(DEV_FD(dev), buf, count, offset);
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}
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/**
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* ntfs_device_unix_io_pwrite - Perform a positioned write to the device
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* @dev:
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* @buf:
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* @count:
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* @offset:
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*
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* Description...
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*
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* Returns:
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*/
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static s64 ntfs_device_unix_io_pwrite(struct ntfs_device *dev, const void *buf,
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s64 count, s64 offset)
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{
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if (NDevReadOnly(dev)) {
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errno = EROFS;
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return -1;
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}
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NDevSetDirty(dev);
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return pwrite(DEV_FD(dev), buf, count, offset);
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}
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/**
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* ntfs_device_unix_io_sync - Flush any buffered changes to the device
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* @dev:
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*
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* Description...
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*
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* Returns:
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*/
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static int ntfs_device_unix_io_sync(struct ntfs_device *dev)
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{
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int res = 0;
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if (!NDevReadOnly(dev)) {
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res = ntfs_fsync(DEV_FD(dev));
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if (res)
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ntfs_log_perror("Failed to sync device %s", dev->d_name);
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else
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NDevClearDirty(dev);
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}
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return res;
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}
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/**
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* ntfs_device_unix_io_stat - Get information about the device
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* @dev:
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* @buf:
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*
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* Description...
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*
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* Returns:
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*/
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static int ntfs_device_unix_io_stat(struct ntfs_device *dev, struct stat *buf)
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{
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return fstat(DEV_FD(dev), buf);
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}
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/**
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* ntfs_device_unix_io_ioctl - Perform an ioctl on the device
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* @dev:
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* @request:
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* @argp:
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*
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* Description...
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*
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* Returns:
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*/
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static int ntfs_device_unix_io_ioctl(struct ntfs_device *dev, int request,
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void *argp)
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{
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return ioctl(DEV_FD(dev), request, argp);
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}
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/**
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* Device operations for working with unix style devices and files.
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*/
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struct ntfs_device_operations ntfs_device_unix_io_ops = {
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.open = ntfs_device_unix_io_open,
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.close = ntfs_device_unix_io_close,
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.seek = ntfs_device_unix_io_seek,
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.read = ntfs_device_unix_io_read,
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.write = ntfs_device_unix_io_write,
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.pread = ntfs_device_unix_io_pread,
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.pwrite = ntfs_device_unix_io_pwrite,
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.sync = ntfs_device_unix_io_sync,
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.stat = ntfs_device_unix_io_stat,
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.ioctl = ntfs_device_unix_io_ioctl,
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};
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