qemu-io: Add discard command

[qemu.git] / block / raw-posix.c

/*
 * Block driver for RAW files (posix)
 *
 * Copyright (c) 2006 Fabrice Bellard
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
#include "qemu-common.h"
#include "qemu-timer.h"
#include "qemu-char.h"
#include "qemu-log.h"
#include "block_int.h"
#include "module.h"
#include "block/raw-posix-aio.h"

#ifdef CONFIG_COCOA
#include <paths.h>
#include <sys/param.h>
#include <IOKit/IOKitLib.h>
#include <IOKit/IOBSD.h>
#include <IOKit/storage/IOMediaBSDClient.h>
#include <IOKit/storage/IOMedia.h>
#include <IOKit/storage/IOCDMedia.h>
//#include <IOKit/storage/IOCDTypes.h>
#include <CoreFoundation/CoreFoundation.h>
#endif

#ifdef __sun__
#define _POSIX_PTHREAD_SEMANTICS 1
#include <signal.h>
#include <sys/dkio.h>
#endif
#ifdef __linux__
#include <sys/ioctl.h>
#include <sys/param.h>
#include <linux/cdrom.h>
#include <linux/fd.h>
#endif
#if defined (__FreeBSD__) || defined(__FreeBSD_kernel__)
#include <signal.h>
#include <sys/disk.h>
#include <sys/cdio.h>
#endif

#ifdef __OpenBSD__
#include <sys/ioctl.h>
#include <sys/disklabel.h>
#include <sys/dkio.h>
#endif

#ifdef __DragonFly__
#include <sys/ioctl.h>
#include <sys/diskslice.h>
#endif

//#define DEBUG_FLOPPY

//#define DEBUG_BLOCK
#if defined(DEBUG_BLOCK)
#define DEBUG_BLOCK_PRINT(formatCstr, ...) do { if (qemu_log_enabled()) \
    { qemu_log(formatCstr, ## __VA_ARGS__); qemu_log_flush(); } } while (0)
#else
#define DEBUG_BLOCK_PRINT(formatCstr, ...)
#endif

/* OS X does not have O_DSYNC */
#ifndef O_DSYNC
#ifdef O_SYNC
#define O_DSYNC O_SYNC
#elif defined(O_FSYNC)
#define O_DSYNC O_FSYNC
#endif
#endif

/* Approximate O_DIRECT with O_DSYNC if O_DIRECT isn't available */
#ifndef O_DIRECT
#define O_DIRECT O_DSYNC
#endif

#define FTYPE_FILE   0
#define FTYPE_CD     1
#define FTYPE_FD     2

/* if the FD is not accessed during that time (in ns), we try to
   reopen it to see if the disk has been changed */
#define FD_OPEN_TIMEOUT (1000000000)

#define MAX_BLOCKSIZE	4096

typedef struct BDRVRawState {
    int fd;
    int type;
    int open_flags;
#if defined(__linux__)
    /* linux floppy specific */
    int64_t fd_open_time;
    int64_t fd_error_time;
    int fd_got_error;
    int fd_media_changed;
#endif
#ifdef CONFIG_LINUX_AIO
    int use_aio;
    void *aio_ctx;
#endif
    uint8_t *aligned_buf;
    unsigned aligned_buf_size;
} BDRVRawState;

static int fd_open(BlockDriverState *bs);
static int64_t raw_getlength(BlockDriverState *bs);

#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
static int cdrom_reopen(BlockDriverState *bs);
#endif

static int raw_open_common(BlockDriverState *bs, const char *filename,
                           int bdrv_flags, int open_flags)
{
    BDRVRawState *s = bs->opaque;
    int fd, ret;

    s->open_flags = open_flags | O_BINARY;
    s->open_flags &= ~O_ACCMODE;
    if (bdrv_flags & BDRV_O_RDWR) {
        s->open_flags |= O_RDWR;
    } else {
        s->open_flags |= O_RDONLY;
    }

    /* Use O_DSYNC for write-through caching, no flags for write-back caching,
     * and O_DIRECT for no caching. */
    if ((bdrv_flags & BDRV_O_NOCACHE))
        s->open_flags |= O_DIRECT;
    else if (!(bdrv_flags & BDRV_O_CACHE_WB))
        s->open_flags |= O_DSYNC;

    s->fd = -1;
    fd = qemu_open(filename, s->open_flags, 0644);
    if (fd < 0) {
        ret = -errno;
        if (ret == -EROFS)
            ret = -EACCES;
        return ret;
    }
    s->fd = fd;
    s->aligned_buf = NULL;

    if ((bdrv_flags & BDRV_O_NOCACHE)) {
        /*
         * Allocate a buffer for read/modify/write cycles.  Chose the size
         * pessimistically as we don't know the block size yet.
         */
        s->aligned_buf_size = 32 * MAX_BLOCKSIZE;
        s->aligned_buf = qemu_memalign(MAX_BLOCKSIZE, s->aligned_buf_size);
        if (s->aligned_buf == NULL) {
            goto out_close;
        }
    }

#ifdef CONFIG_LINUX_AIO
    if ((bdrv_flags & (BDRV_O_NOCACHE|BDRV_O_NATIVE_AIO)) ==
                      (BDRV_O_NOCACHE|BDRV_O_NATIVE_AIO)) {

        /* We're falling back to POSIX AIO in some cases */
        paio_init();

        s->aio_ctx = laio_init();
        if (!s->aio_ctx) {
            goto out_free_buf;
        }
        s->use_aio = 1;
    } else
#endif
    {
        if (paio_init() < 0) {
            goto out_free_buf;
        }
#ifdef CONFIG_LINUX_AIO
        s->use_aio = 0;
#endif
    }

    return 0;

out_free_buf:
    qemu_vfree(s->aligned_buf);
out_close:
    close(fd);
    return -errno;
}

static int raw_open(BlockDriverState *bs, const char *filename, int flags)
{
    BDRVRawState *s = bs->opaque;

    s->type = FTYPE_FILE;
    return raw_open_common(bs, filename, flags, 0);
}

/* XXX: use host sector size if necessary with:
#ifdef DIOCGSECTORSIZE
        {
            unsigned int sectorsize = 512;
            if (!ioctl(fd, DIOCGSECTORSIZE, &sectorsize) &&
                sectorsize > bufsize)
                bufsize = sectorsize;
        }
#endif
#ifdef CONFIG_COCOA
        uint32_t blockSize = 512;
        if ( !ioctl( fd, DKIOCGETBLOCKSIZE, &blockSize ) && blockSize > bufsize) {
            bufsize = blockSize;
        }
#endif
*/

/*
 * offset and count are in bytes, but must be multiples of 512 for files
 * opened with O_DIRECT. buf must be aligned to 512 bytes then.
 *
 * This function may be called without alignment if the caller ensures
 * that O_DIRECT is not in effect.
 */
static int raw_pread_aligned(BlockDriverState *bs, int64_t offset,
                     uint8_t *buf, int count)
{
    BDRVRawState *s = bs->opaque;
    int ret;

    ret = fd_open(bs);
    if (ret < 0)
        return ret;

    ret = pread(s->fd, buf, count, offset);
    if (ret == count)
        return ret;

    /* Allow reads beyond the end (needed for pwrite) */
    if ((ret == 0) && bs->growable) {
        int64_t size = raw_getlength(bs);
        if (offset >= size) {
            memset(buf, 0, count);
            return count;
        }
    }

    DEBUG_BLOCK_PRINT("raw_pread(%d:%s, %" PRId64 ", %p, %d) [%" PRId64
                      "] read failed %d : %d = %s\n",
                      s->fd, bs->filename, offset, buf, count,
                      bs->total_sectors, ret, errno, strerror(errno));

    /* Try harder for CDrom. */
    if (s->type != FTYPE_FILE) {
        ret = pread(s->fd, buf, count, offset);
        if (ret == count)
            return ret;
        ret = pread(s->fd, buf, count, offset);
        if (ret == count)
            return ret;

        DEBUG_BLOCK_PRINT("raw_pread(%d:%s, %" PRId64 ", %p, %d) [%" PRId64
                          "] retry read failed %d : %d = %s\n",
                          s->fd, bs->filename, offset, buf, count,
                          bs->total_sectors, ret, errno, strerror(errno));
    }

    return  (ret < 0) ? -errno : ret;
}

/*
 * offset and count are in bytes, but must be multiples of the sector size
 * for files opened with O_DIRECT. buf must be aligned to sector size bytes
 * then.
 *
 * This function may be called without alignment if the caller ensures
 * that O_DIRECT is not in effect.
 */
static int raw_pwrite_aligned(BlockDriverState *bs, int64_t offset,
                      const uint8_t *buf, int count)
{
    BDRVRawState *s = bs->opaque;
    int ret;

    ret = fd_open(bs);
    if (ret < 0)
        return -errno;

    ret = pwrite(s->fd, buf, count, offset);
    if (ret == count)
        return ret;

    DEBUG_BLOCK_PRINT("raw_pwrite(%d:%s, %" PRId64 ", %p, %d) [%" PRId64
                      "] write failed %d : %d = %s\n",
                      s->fd, bs->filename, offset, buf, count,
                      bs->total_sectors, ret, errno, strerror(errno));

    return  (ret < 0) ? -errno : ret;
}


/*
 * offset and count are in bytes and possibly not aligned. For files opened
 * with O_DIRECT, necessary alignments are ensured before calling
 * raw_pread_aligned to do the actual read.
 */
static int raw_pread(BlockDriverState *bs, int64_t offset,
                     uint8_t *buf, int count)
{
    BDRVRawState *s = bs->opaque;
    unsigned sector_mask = bs->buffer_alignment - 1;
    int size, ret, shift, sum;

    sum = 0;

    if (s->aligned_buf != NULL)  {

        if (offset & sector_mask) {
            /* align offset on a sector size bytes boundary */

            shift = offset & sector_mask;
            size = (shift + count + sector_mask) & ~sector_mask;
            if (size > s->aligned_buf_size)
                size = s->aligned_buf_size;
            ret = raw_pread_aligned(bs, offset - shift, s->aligned_buf, size);
            if (ret < 0)
                return ret;

            size = bs->buffer_alignment - shift;
            if (size > count)
                size = count;
            memcpy(buf, s->aligned_buf + shift, size);

            buf += size;
            offset += size;
            count -= size;
            sum += size;

            if (count == 0)
                return sum;
        }
        if (count & sector_mask || (uintptr_t) buf & sector_mask) {

            /* read on aligned buffer */

            while (count) {

                size = (count + sector_mask) & ~sector_mask;
                if (size > s->aligned_buf_size)
                    size = s->aligned_buf_size;

                ret = raw_pread_aligned(bs, offset, s->aligned_buf, size);
                if (ret < 0) {
                    return ret;
                } else if (ret == 0) {
                    fprintf(stderr, "raw_pread: read beyond end of file\n");
                    abort();
                }

                size = ret;
                if (size > count)
                    size = count;

                memcpy(buf, s->aligned_buf, size);

                buf += size;
                offset += size;
                count -= size;
                sum += size;
            }

            return sum;
        }
    }

    return raw_pread_aligned(bs, offset, buf, count) + sum;
}

static int raw_read(BlockDriverState *bs, int64_t sector_num,
                    uint8_t *buf, int nb_sectors)
{
    int ret;

    ret = raw_pread(bs, sector_num * BDRV_SECTOR_SIZE, buf,
                    nb_sectors * BDRV_SECTOR_SIZE);
    if (ret == (nb_sectors * BDRV_SECTOR_SIZE))
        ret = 0;
    return ret;
}

/*
 * offset and count are in bytes and possibly not aligned. For files opened
 * with O_DIRECT, necessary alignments are ensured before calling
 * raw_pwrite_aligned to do the actual write.
 */
static int raw_pwrite(BlockDriverState *bs, int64_t offset,
                      const uint8_t *buf, int count)
{
    BDRVRawState *s = bs->opaque;
    unsigned sector_mask = bs->buffer_alignment - 1;
    int size, ret, shift, sum;

    sum = 0;

    if (s->aligned_buf != NULL) {

        if (offset & sector_mask) {
            /* align offset on a sector size bytes boundary */
            shift = offset & sector_mask;
            ret = raw_pread_aligned(bs, offset - shift, s->aligned_buf,
                                    bs->buffer_alignment);
            if (ret < 0)
                return ret;

            size = bs->buffer_alignment - shift;
            if (size > count)
                size = count;
            memcpy(s->aligned_buf + shift, buf, size);

            ret = raw_pwrite_aligned(bs, offset - shift, s->aligned_buf,
                                     bs->buffer_alignment);
            if (ret < 0)
                return ret;

            buf += size;
            offset += size;
            count -= size;
            sum += size;

            if (count == 0)
                return sum;
        }
        if (count & sector_mask || (uintptr_t) buf & sector_mask) {

            while ((size = (count & ~sector_mask)) != 0) {

                if (size > s->aligned_buf_size)
                    size = s->aligned_buf_size;

                memcpy(s->aligned_buf, buf, size);

                ret = raw_pwrite_aligned(bs, offset, s->aligned_buf, size);
                if (ret < 0)
                    return ret;

                buf += ret;
                offset += ret;
                count -= ret;
                sum += ret;
            }
            /* here, count < sector_size because (count & ~sector_mask) == 0 */
            if (count) {
                ret = raw_pread_aligned(bs, offset, s->aligned_buf,
                                     bs->buffer_alignment);
                if (ret < 0)
                    return ret;
                 memcpy(s->aligned_buf, buf, count);

                 ret = raw_pwrite_aligned(bs, offset, s->aligned_buf,
                                     bs->buffer_alignment);
                 if (ret < 0)
                     return ret;
                 if (count < ret)
                     ret = count;

                 sum += ret;
            }
            return sum;
        }
    }
    return raw_pwrite_aligned(bs, offset, buf, count) + sum;
}

static int raw_write(BlockDriverState *bs, int64_t sector_num,
                     const uint8_t *buf, int nb_sectors)
{
    int ret;
    ret = raw_pwrite(bs, sector_num * BDRV_SECTOR_SIZE, buf,
                     nb_sectors * BDRV_SECTOR_SIZE);
    if (ret == (nb_sectors * BDRV_SECTOR_SIZE))
        ret = 0;
    return ret;
}

/*
 * Check if all memory in this vector is sector aligned.
 */
static int qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov)
{
    int i;

    for (i = 0; i < qiov->niov; i++) {
        if ((uintptr_t) qiov->iov[i].iov_base % bs->buffer_alignment) {
            return 0;
        }
    }

    return 1;
}

static BlockDriverAIOCB *raw_aio_submit(BlockDriverState *bs,
        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
        BlockDriverCompletionFunc *cb, void *opaque, int type)
{
    BDRVRawState *s = bs->opaque;

    if (fd_open(bs) < 0)
        return NULL;

    /*
     * If O_DIRECT is used the buffer needs to be aligned on a sector
     * boundary.  Check if this is the case or telll the low-level
     * driver that it needs to copy the buffer.
     */
    if (s->aligned_buf) {
        if (!qiov_is_aligned(bs, qiov)) {
            type |= QEMU_AIO_MISALIGNED;
#ifdef CONFIG_LINUX_AIO
        } else if (s->use_aio) {
            return laio_submit(bs, s->aio_ctx, s->fd, sector_num, qiov,
                               nb_sectors, cb, opaque, type);
#endif
        }
    }

    return paio_submit(bs, s->fd, sector_num, qiov, nb_sectors,
                       cb, opaque, type);
}

static BlockDriverAIOCB *raw_aio_readv(BlockDriverState *bs,
        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
        BlockDriverCompletionFunc *cb, void *opaque)
{
    return raw_aio_submit(bs, sector_num, qiov, nb_sectors,
                          cb, opaque, QEMU_AIO_READ);
}

static BlockDriverAIOCB *raw_aio_writev(BlockDriverState *bs,
        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
        BlockDriverCompletionFunc *cb, void *opaque)
{
    return raw_aio_submit(bs, sector_num, qiov, nb_sectors,
                          cb, opaque, QEMU_AIO_WRITE);
}

static BlockDriverAIOCB *raw_aio_flush(BlockDriverState *bs,
        BlockDriverCompletionFunc *cb, void *opaque)
{
    BDRVRawState *s = bs->opaque;

    if (fd_open(bs) < 0)
        return NULL;

    return paio_submit(bs, s->fd, 0, NULL, 0, cb, opaque, QEMU_AIO_FLUSH);
}

static void raw_close(BlockDriverState *bs)
{
    BDRVRawState *s = bs->opaque;
    if (s->fd >= 0) {
        close(s->fd);
        s->fd = -1;
        if (s->aligned_buf != NULL)
            qemu_vfree(s->aligned_buf);
    }
}

static int raw_truncate(BlockDriverState *bs, int64_t offset)
{
    BDRVRawState *s = bs->opaque;
    if (s->type != FTYPE_FILE)
        return -ENOTSUP;
    if (ftruncate(s->fd, offset) < 0)
        return -errno;
    return 0;
}

#ifdef __OpenBSD__
static int64_t raw_getlength(BlockDriverState *bs)
{
    BDRVRawState *s = bs->opaque;
    int fd = s->fd;
    struct stat st;

    if (fstat(fd, &st))
        return -1;
    if (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)) {
        struct disklabel dl;

        if (ioctl(fd, DIOCGDINFO, &dl))
            return -1;
        return (uint64_t)dl.d_secsize *
            dl.d_partitions[DISKPART(st.st_rdev)].p_size;
    } else
        return st.st_size;
}
#elif defined(__sun__)
static int64_t raw_getlength(BlockDriverState *bs)
{
    BDRVRawState *s = bs->opaque;
    struct dk_minfo minfo;
    int ret;

    ret = fd_open(bs);
    if (ret < 0) {
        return ret;
    }

    /*
     * Use the DKIOCGMEDIAINFO ioctl to read the size.
     */
    ret = ioctl(s->fd, DKIOCGMEDIAINFO, &minfo);
    if (ret != -1) {
        return minfo.dki_lbsize * minfo.dki_capacity;
    }

    /*
     * There are reports that lseek on some devices fails, but
     * irc discussion said that contingency on contingency was overkill.
     */
    return lseek(s->fd, 0, SEEK_END);
}
#elif defined(CONFIG_BSD)
static int64_t raw_getlength(BlockDriverState *bs)
{
    BDRVRawState *s = bs->opaque;
    int fd = s->fd;
    int64_t size;
    struct stat sb;
#if defined (__FreeBSD__) || defined(__FreeBSD_kernel__)
    int reopened = 0;
#endif
    int ret;

    ret = fd_open(bs);
    if (ret < 0)
        return ret;

#if defined (__FreeBSD__) || defined(__FreeBSD_kernel__)
again:
#endif
    if (!fstat(fd, &sb) && (S_IFCHR & sb.st_mode)) {
#ifdef DIOCGMEDIASIZE
	if (ioctl(fd, DIOCGMEDIASIZE, (off_t *)&size))
#elif defined(DIOCGPART)
        {
                struct partinfo pi;
                if (ioctl(fd, DIOCGPART, &pi) == 0)
                        size = pi.media_size;
                else
                        size = 0;
        }
        if (size == 0)
#endif
#ifdef CONFIG_COCOA
        size = LONG_LONG_MAX;
#else
        size = lseek(fd, 0LL, SEEK_END);
#endif
#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
        switch(s->type) {
        case FTYPE_CD:
            /* XXX FreeBSD acd returns UINT_MAX sectors for an empty drive */
            if (size == 2048LL * (unsigned)-1)
                size = 0;
            /* XXX no disc?  maybe we need to reopen... */
            if (size <= 0 && !reopened && cdrom_reopen(bs) >= 0) {
                reopened = 1;
                goto again;
            }
        }
#endif
    } else {
        size = lseek(fd, 0, SEEK_END);
    }
    return size;
}
#else
static int64_t raw_getlength(BlockDriverState *bs)
{
    BDRVRawState *s = bs->opaque;
    int ret;

    ret = fd_open(bs);
    if (ret < 0) {
        return ret;
    }

    return lseek(s->fd, 0, SEEK_END);
}
#endif

static int raw_create(const char *filename, QEMUOptionParameter *options)
{
    int fd;
    int result = 0;
    int64_t total_size = 0;

    /* Read out options */
    while (options && options->name) {
        if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
            total_size = options->value.n / BDRV_SECTOR_SIZE;
        }
        options++;
    }

    fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
              0644);
    if (fd < 0) {
        result = -errno;
    } else {
        if (ftruncate(fd, total_size * BDRV_SECTOR_SIZE) != 0) {
            result = -errno;
        }
        if (close(fd) != 0) {
            result = -errno;
        }
    }
    return result;
}

static int raw_flush(BlockDriverState *bs)
{
    BDRVRawState *s = bs->opaque;
    return qemu_fdatasync(s->fd);
}


static QEMUOptionParameter raw_create_options[] = {
    {
        .name = BLOCK_OPT_SIZE,
        .type = OPT_SIZE,
        .help = "Virtual disk size"
    },
    { NULL }
};

static BlockDriver bdrv_file = {
    .format_name = "file",
    .protocol_name = "file",
    .instance_size = sizeof(BDRVRawState),
    .bdrv_probe = NULL, /* no probe for protocols */
    .bdrv_file_open = raw_open,
    .bdrv_read = raw_read,
    .bdrv_write = raw_write,
    .bdrv_close = raw_close,
    .bdrv_create = raw_create,
    .bdrv_flush = raw_flush,

    .bdrv_aio_readv = raw_aio_readv,
    .bdrv_aio_writev = raw_aio_writev,
    .bdrv_aio_flush = raw_aio_flush,

    .bdrv_truncate = raw_truncate,
    .bdrv_getlength = raw_getlength,

    .create_options = raw_create_options,
};

/***********************************************/
/* host device */

#ifdef CONFIG_COCOA
static kern_return_t FindEjectableCDMedia( io_iterator_t *mediaIterator );
static kern_return_t GetBSDPath( io_iterator_t mediaIterator, char *bsdPath, CFIndex maxPathSize );

kern_return_t FindEjectableCDMedia( io_iterator_t *mediaIterator )
{
    kern_return_t       kernResult;
    mach_port_t     masterPort;
    CFMutableDictionaryRef  classesToMatch;

    kernResult = IOMasterPort( MACH_PORT_NULL, &masterPort );
    if ( KERN_SUCCESS != kernResult ) {
        printf( "IOMasterPort returned %d\n", kernResult );
    }

    classesToMatch = IOServiceMatching( kIOCDMediaClass );
    if ( classesToMatch == NULL ) {
        printf( "IOServiceMatching returned a NULL dictionary.\n" );
    } else {
    CFDictionarySetValue( classesToMatch, CFSTR( kIOMediaEjectableKey ), kCFBooleanTrue );
    }
    kernResult = IOServiceGetMatchingServices( masterPort, classesToMatch, mediaIterator );
    if ( KERN_SUCCESS != kernResult )
    {
        printf( "IOServiceGetMatchingServices returned %d\n", kernResult );
    }

    return kernResult;
}

kern_return_t GetBSDPath( io_iterator_t mediaIterator, char *bsdPath, CFIndex maxPathSize )
{
    io_object_t     nextMedia;
    kern_return_t   kernResult = KERN_FAILURE;
    *bsdPath = '\0';
    nextMedia = IOIteratorNext( mediaIterator );
    if ( nextMedia )
    {
        CFTypeRef   bsdPathAsCFString;
    bsdPathAsCFString = IORegistryEntryCreateCFProperty( nextMedia, CFSTR( kIOBSDNameKey ), kCFAllocatorDefault, 0 );
        if ( bsdPathAsCFString ) {
            size_t devPathLength;
            strcpy( bsdPath, _PATH_DEV );
            strcat( bsdPath, "r" );
            devPathLength = strlen( bsdPath );
            if ( CFStringGetCString( bsdPathAsCFString, bsdPath + devPathLength, maxPathSize - devPathLength, kCFStringEncodingASCII ) ) {
                kernResult = KERN_SUCCESS;
            }
            CFRelease( bsdPathAsCFString );
        }
        IOObjectRelease( nextMedia );
    }

    return kernResult;
}

#endif

static int hdev_probe_device(const char *filename)
{
    struct stat st;

    /* allow a dedicated CD-ROM driver to match with a higher priority */
    if (strstart(filename, "/dev/cdrom", NULL))
        return 50;

    if (stat(filename, &st) >= 0 &&
            (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode))) {
        return 100;
    }

    return 0;
}

static int hdev_open(BlockDriverState *bs, const char *filename, int flags)
{
    BDRVRawState *s = bs->opaque;

#ifdef CONFIG_COCOA
    if (strstart(filename, "/dev/cdrom", NULL)) {
        kern_return_t kernResult;
        io_iterator_t mediaIterator;
        char bsdPath[ MAXPATHLEN ];
        int fd;

        kernResult = FindEjectableCDMedia( &mediaIterator );
        kernResult = GetBSDPath( mediaIterator, bsdPath, sizeof( bsdPath ) );

        if ( bsdPath[ 0 ] != '\0' ) {
            strcat(bsdPath,"s0");
            /* some CDs don't have a partition 0 */
            fd = open(bsdPath, O_RDONLY | O_BINARY | O_LARGEFILE);
            if (fd < 0) {
                bsdPath[strlen(bsdPath)-1] = '1';
            } else {
                close(fd);
            }
            filename = bsdPath;
        }

        if ( mediaIterator )
            IOObjectRelease( mediaIterator );
    }
#endif

    s->type = FTYPE_FILE;
#if defined(__linux__)
    {
        char resolved_path[ MAXPATHLEN ], *temp;

        temp = realpath(filename, resolved_path);
        if (temp && strstart(temp, "/dev/sg", NULL)) {
            bs->sg = 1;
        }
    }
#endif

    return raw_open_common(bs, filename, flags, 0);
}

#if defined(__linux__)
/* Note: we do not have a reliable method to detect if the floppy is
   present. The current method is to try to open the floppy at every
   I/O and to keep it opened during a few hundreds of ms. */
static int fd_open(BlockDriverState *bs)
{
    BDRVRawState *s = bs->opaque;
    int last_media_present;

    if (s->type != FTYPE_FD)
        return 0;
    last_media_present = (s->fd >= 0);
    if (s->fd >= 0 &&
        (get_clock() - s->fd_open_time) >= FD_OPEN_TIMEOUT) {
        close(s->fd);
        s->fd = -1;
#ifdef DEBUG_FLOPPY
        printf("Floppy closed\n");
#endif
    }
    if (s->fd < 0) {
        if (s->fd_got_error &&
            (get_clock() - s->fd_error_time) < FD_OPEN_TIMEOUT) {
#ifdef DEBUG_FLOPPY
            printf("No floppy (open delayed)\n");
#endif
            return -EIO;
        }
        s->fd = open(bs->filename, s->open_flags & ~O_NONBLOCK);
        if (s->fd < 0) {
            s->fd_error_time = get_clock();
            s->fd_got_error = 1;
            if (last_media_present)
                s->fd_media_changed = 1;
#ifdef DEBUG_FLOPPY
            printf("No floppy\n");
#endif
            return -EIO;
        }
#ifdef DEBUG_FLOPPY
        printf("Floppy opened\n");
#endif
    }
    if (!last_media_present)
        s->fd_media_changed = 1;
    s->fd_open_time = get_clock();
    s->fd_got_error = 0;
    return 0;
}

static int hdev_ioctl(BlockDriverState *bs, unsigned long int req, void *buf)
{
    BDRVRawState *s = bs->opaque;

    return ioctl(s->fd, req, buf);
}

static BlockDriverAIOCB *hdev_aio_ioctl(BlockDriverState *bs,
        unsigned long int req, void *buf,
        BlockDriverCompletionFunc *cb, void *opaque)
{
    BDRVRawState *s = bs->opaque;

    if (fd_open(bs) < 0)
        return NULL;
    return paio_ioctl(bs, s->fd, req, buf, cb, opaque);
}

#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
static int fd_open(BlockDriverState *bs)
{
    BDRVRawState *s = bs->opaque;

    /* this is just to ensure s->fd is sane (its called by io ops) */
    if (s->fd >= 0)
        return 0;
    return -EIO;
}
#else /* !linux && !FreeBSD */

static int fd_open(BlockDriverState *bs)
{
    return 0;
}

#endif /* !linux && !FreeBSD */

static int hdev_create(const char *filename, QEMUOptionParameter *options)
{
    int fd;
    int ret = 0;
    struct stat stat_buf;
    int64_t total_size = 0;

    /* Read out options */
    while (options && options->name) {
        if (!strcmp(options->name, "size")) {
            total_size = options->value.n / BDRV_SECTOR_SIZE;
        }
        options++;
    }

    fd = open(filename, O_WRONLY | O_BINARY);
    if (fd < 0)
        return -errno;

    if (fstat(fd, &stat_buf) < 0)
        ret = -errno;
    else if (!S_ISBLK(stat_buf.st_mode) && !S_ISCHR(stat_buf.st_mode))
        ret = -ENODEV;
    else if (lseek(fd, 0, SEEK_END) < total_size * BDRV_SECTOR_SIZE)
        ret = -ENOSPC;

    close(fd);
    return ret;
}

static int hdev_has_zero_init(BlockDriverState *bs)
{
    return 0;
}

static BlockDriver bdrv_host_device = {
    .format_name        = "host_device",
    .protocol_name        = "host_device",
    .instance_size      = sizeof(BDRVRawState),
    .bdrv_probe_device  = hdev_probe_device,
    .bdrv_file_open     = hdev_open,
    .bdrv_close         = raw_close,
    .bdrv_create        = hdev_create,
    .create_options     = raw_create_options,
    .bdrv_has_zero_init = hdev_has_zero_init,
    .bdrv_flush         = raw_flush,

    .bdrv_aio_readv	= raw_aio_readv,
    .bdrv_aio_writev	= raw_aio_writev,
    .bdrv_aio_flush	= raw_aio_flush,

    .bdrv_read          = raw_read,
    .bdrv_write         = raw_write,
    .bdrv_getlength	= raw_getlength,

    /* generic scsi device */
#ifdef __linux__
    .bdrv_ioctl         = hdev_ioctl,
    .bdrv_aio_ioctl     = hdev_aio_ioctl,
#endif
};

#ifdef __linux__
static int floppy_open(BlockDriverState *bs, const char *filename, int flags)
{
    BDRVRawState *s = bs->opaque;
    int ret;

    s->type = FTYPE_FD;

    /* open will not fail even if no floppy is inserted, so add O_NONBLOCK */
    ret = raw_open_common(bs, filename, flags, O_NONBLOCK);
    if (ret)
        return ret;

    /* close fd so that we can reopen it as needed */
    close(s->fd);
    s->fd = -1;
    s->fd_media_changed = 1;

    return 0;
}

static int floppy_probe_device(const char *filename)
{
    int fd, ret;
    int prio = 0;
    struct floppy_struct fdparam;

    if (strstart(filename, "/dev/fd", NULL))
        prio = 50;

    fd = open(filename, O_RDONLY | O_NONBLOCK);
    if (fd < 0) {
        goto out;
    }

    /* Attempt to detect via a floppy specific ioctl */
    ret = ioctl(fd, FDGETPRM, &fdparam);
    if (ret >= 0)
        prio = 100;

    close(fd);
out:
    return prio;
}


static int floppy_is_inserted(BlockDriverState *bs)
{
    return fd_open(bs) >= 0;
}

static int floppy_media_changed(BlockDriverState *bs)
{
    BDRVRawState *s = bs->opaque;
    int ret;

    /*
     * XXX: we do not have a true media changed indication.
     * It does not work if the floppy is changed without trying to read it.
     */
    fd_open(bs);
    ret = s->fd_media_changed;
    s->fd_media_changed = 0;
#ifdef DEBUG_FLOPPY
    printf("Floppy changed=%d\n", ret);
#endif
    return ret;
}

static int floppy_eject(BlockDriverState *bs, int eject_flag)
{
    BDRVRawState *s = bs->opaque;
    int fd;

    if (s->fd >= 0) {
        close(s->fd);
        s->fd = -1;
    }
    fd = open(bs->filename, s->open_flags | O_NONBLOCK);
    if (fd >= 0) {
        if (ioctl(fd, FDEJECT, 0) < 0)
            perror("FDEJECT");
        close(fd);
    }

    return 0;
}

static BlockDriver bdrv_host_floppy = {
    .format_name        = "host_floppy",
    .protocol_name      = "host_floppy",
    .instance_size      = sizeof(BDRVRawState),
    .bdrv_probe_device	= floppy_probe_device,
    .bdrv_file_open     = floppy_open,
    .bdrv_close         = raw_close,
    .bdrv_create        = hdev_create,
    .create_options     = raw_create_options,
    .bdrv_has_zero_init = hdev_has_zero_init,
    .bdrv_flush         = raw_flush,

    .bdrv_aio_readv     = raw_aio_readv,
    .bdrv_aio_writev    = raw_aio_writev,
    .bdrv_aio_flush	= raw_aio_flush,

    .bdrv_read          = raw_read,
    .bdrv_write         = raw_write,
    .bdrv_getlength	= raw_getlength,

    /* removable device support */
    .bdrv_is_inserted   = floppy_is_inserted,
    .bdrv_media_changed = floppy_media_changed,
    .bdrv_eject         = floppy_eject,
};

static int cdrom_open(BlockDriverState *bs, const char *filename, int flags)
{
    BDRVRawState *s = bs->opaque;

    s->type = FTYPE_CD;

    /* open will not fail even if no CD is inserted, so add O_NONBLOCK */
    return raw_open_common(bs, filename, flags, O_NONBLOCK);
}

static int cdrom_probe_device(const char *filename)
{
    int fd, ret;
    int prio = 0;

    fd = open(filename, O_RDONLY | O_NONBLOCK);
    if (fd < 0) {
        goto out;
    }

    /* Attempt to detect via a CDROM specific ioctl */
    ret = ioctl(fd, CDROM_DRIVE_STATUS, CDSL_CURRENT);
    if (ret >= 0)
        prio = 100;

    close(fd);
out:
    return prio;
}

static int cdrom_is_inserted(BlockDriverState *bs)
{
    BDRVRawState *s = bs->opaque;
    int ret;

    ret = ioctl(s->fd, CDROM_DRIVE_STATUS, CDSL_CURRENT);
    if (ret == CDS_DISC_OK)
        return 1;
    return 0;
}

static int cdrom_eject(BlockDriverState *bs, int eject_flag)
{
    BDRVRawState *s = bs->opaque;

    if (eject_flag) {
        if (ioctl(s->fd, CDROMEJECT, NULL) < 0)
            perror("CDROMEJECT");
    } else {
        if (ioctl(s->fd, CDROMCLOSETRAY, NULL) < 0)
            perror("CDROMEJECT");
    }

    return 0;
}

static int cdrom_set_locked(BlockDriverState *bs, int locked)
{
    BDRVRawState *s = bs->opaque;

    if (ioctl(s->fd, CDROM_LOCKDOOR, locked) < 0) {
        /*
         * Note: an error can happen if the distribution automatically
         * mounts the CD-ROM
         */
        /* perror("CDROM_LOCKDOOR"); */
    }

    return 0;
}

static BlockDriver bdrv_host_cdrom = {
    .format_name        = "host_cdrom",
    .protocol_name      = "host_cdrom",
    .instance_size      = sizeof(BDRVRawState),
    .bdrv_probe_device	= cdrom_probe_device,
    .bdrv_file_open     = cdrom_open,
    .bdrv_close         = raw_close,
    .bdrv_create        = hdev_create,
    .create_options     = raw_create_options,
    .bdrv_has_zero_init = hdev_has_zero_init,
    .bdrv_flush         = raw_flush,

    .bdrv_aio_readv     = raw_aio_readv,
    .bdrv_aio_writev    = raw_aio_writev,
    .bdrv_aio_flush	= raw_aio_flush,

    .bdrv_read          = raw_read,
    .bdrv_write         = raw_write,
    .bdrv_getlength     = raw_getlength,

    /* removable device support */
    .bdrv_is_inserted   = cdrom_is_inserted,
    .bdrv_eject         = cdrom_eject,
    .bdrv_set_locked    = cdrom_set_locked,

    /* generic scsi device */
    .bdrv_ioctl         = hdev_ioctl,
    .bdrv_aio_ioctl     = hdev_aio_ioctl,
};
#endif /* __linux__ */

#if defined (__FreeBSD__) || defined(__FreeBSD_kernel__)
static int cdrom_open(BlockDriverState *bs, const char *filename, int flags)
{
    BDRVRawState *s = bs->opaque;
    int ret;

    s->type = FTYPE_CD;

    ret = raw_open_common(bs, filename, flags, 0);
    if (ret)
        return ret;

    /* make sure the door isnt locked at this time */
    ioctl(s->fd, CDIOCALLOW);
    return 0;
}

static int cdrom_probe_device(const char *filename)
{
    if (strstart(filename, "/dev/cd", NULL) ||
            strstart(filename, "/dev/acd", NULL))
        return 100;
    return 0;
}

static int cdrom_reopen(BlockDriverState *bs)
{
    BDRVRawState *s = bs->opaque;
    int fd;

    /*
     * Force reread of possibly changed/newly loaded disc,
     * FreeBSD seems to not notice sometimes...
     */
    if (s->fd >= 0)
        close(s->fd);
    fd = open(bs->filename, s->open_flags, 0644);
    if (fd < 0) {
        s->fd = -1;
        return -EIO;
    }
    s->fd = fd;

    /* make sure the door isnt locked at this time */
    ioctl(s->fd, CDIOCALLOW);
    return 0;
}

static int cdrom_is_inserted(BlockDriverState *bs)
{
    return raw_getlength(bs) > 0;
}

static int cdrom_eject(BlockDriverState *bs, int eject_flag)
{
    BDRVRawState *s = bs->opaque;

    if (s->fd < 0)
        return -ENOTSUP;

    (void) ioctl(s->fd, CDIOCALLOW);

    if (eject_flag) {
        if (ioctl(s->fd, CDIOCEJECT) < 0)
            perror("CDIOCEJECT");
    } else {
        if (ioctl(s->fd, CDIOCCLOSE) < 0)
            perror("CDIOCCLOSE");
    }

    if (cdrom_reopen(bs) < 0)
        return -ENOTSUP;
    return 0;
}

static int cdrom_set_locked(BlockDriverState *bs, int locked)
{
    BDRVRawState *s = bs->opaque;

    if (s->fd < 0)
        return -ENOTSUP;
    if (ioctl(s->fd, (locked ? CDIOCPREVENT : CDIOCALLOW)) < 0) {
        /*
         * Note: an error can happen if the distribution automatically
         * mounts the CD-ROM
         */
        /* perror("CDROM_LOCKDOOR"); */
    }

    return 0;
}

static BlockDriver bdrv_host_cdrom = {
    .format_name        = "host_cdrom",
    .protocol_name      = "host_cdrom",
    .instance_size      = sizeof(BDRVRawState),
    .bdrv_probe_device	= cdrom_probe_device,
    .bdrv_file_open     = cdrom_open,
    .bdrv_close         = raw_close,
    .bdrv_create        = hdev_create,
    .create_options     = raw_create_options,
    .bdrv_has_zero_init = hdev_has_zero_init,
    .bdrv_flush         = raw_flush,

    .bdrv_aio_readv     = raw_aio_readv,
    .bdrv_aio_writev    = raw_aio_writev,
    .bdrv_aio_flush	= raw_aio_flush,

    .bdrv_read          = raw_read,
    .bdrv_write         = raw_write,
    .bdrv_getlength     = raw_getlength,

    /* removable device support */
    .bdrv_is_inserted   = cdrom_is_inserted,
    .bdrv_eject         = cdrom_eject,
    .bdrv_set_locked    = cdrom_set_locked,
};
#endif /* __FreeBSD__ */

static void bdrv_file_init(void)
{
    /*
     * Register all the drivers.  Note that order is important, the driver
     * registered last will get probed first.
     */
    bdrv_register(&bdrv_file);
    bdrv_register(&bdrv_host_device);
#ifdef __linux__
    bdrv_register(&bdrv_host_floppy);
    bdrv_register(&bdrv_host_cdrom);
#endif
#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
    bdrv_register(&bdrv_host_cdrom);
#endif
}

block_init(bdrv_file_init);