Archipelago » qemu

/*

 * 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"

#if !defined(QEMU_IMG) && !defined(QEMU_NBD)

#include "qemu-timer.h"

#include "exec-all.h"

#endif

#include "block_int.h"

#include <assert.h>

#ifdef CONFIG_AIO

#include <aio.h>

#endif

#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 <linux/cdrom.h>

#include <linux/fd.h>

#endif

#ifdef __FreeBSD__

#include <sys/disk.h>

#endif

//#define DEBUG_FLOPPY

//#define DEBUG_BLOCK

#if defined(DEBUG_BLOCK) && !defined(QEMU_IMG) && !defined(QEMU_NBD)

#define DEBUG_BLOCK_PRINT(formatCstr, args...) do { if (loglevel != 0)        \

    { fprintf(logfile, formatCstr, ##args); fflush(logfile); } } while (0)

#else

#define DEBUG_BLOCK_PRINT(formatCstr, args...)

#endif

#define FTYPE_FILE   0

#define FTYPE_CD     1

#define FTYPE_FD     2

#define ALIGNED_BUFFER_SIZE (32 * 512)

/* if the FD is not accessed during that time (in ms), we try to

   reopen it to see if the disk has been changed */

#define FD_OPEN_TIMEOUT 1000

typedef struct BDRVRawState {

    int fd;

    int type;

    unsigned int lseek_err_cnt;

#if defined(__linux__)

    /* linux floppy specific */

    int fd_open_flags;

    int64_t fd_open_time;

    int64_t fd_error_time;

    int fd_got_error;

    int fd_media_changed;

#endif

#if defined(O_DIRECT) && !defined(QEMU_IMG)

    uint8_t* aligned_buf;

#endif

} BDRVRawState;

static int fd_open(BlockDriverState *bs);

static int raw_open(BlockDriverState *bs, const char *filename, int flags)

{

    BDRVRawState *s = bs->opaque;

    int fd, open_flags, ret;

    s->lseek_err_cnt = 0;

    open_flags = O_BINARY;

    if ((flags & BDRV_O_ACCESS) == O_RDWR) {

        open_flags |= O_RDWR;

    } else {

        open_flags |= O_RDONLY;

        bs->read_only = 1;

    }

    if (flags & BDRV_O_CREAT)

        open_flags |= O_CREAT | O_TRUNC;

#ifdef O_DIRECT

    if (flags & BDRV_O_DIRECT)

        open_flags |= O_DIRECT;

#endif

    s->type = FTYPE_FILE;

    fd = open(filename, open_flags, 0644);

    if (fd < 0) {

        ret = -errno;

        if (ret == -EROFS)

            ret = -EACCES;

        return ret;

    }

    s->fd = fd;

#if defined(O_DIRECT) && !defined(QEMU_IMG)

    s->aligned_buf = NULL;

    if (flags & BDRV_O_DIRECT) {

        s->aligned_buf = qemu_memalign(512, ALIGNED_BUFFER_SIZE);

        if (s->aligned_buf == NULL) {

            ret = -errno;

            close(fd);

            return ret;

        }

    }

#endif

    return 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

        u_int32_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;

    if (offset >= 0 && lseek(s->fd, offset, SEEK_SET) == (off_t)-1) {

        ++(s->lseek_err_cnt);

        if(s->lseek_err_cnt <= 10) {

            DEBUG_BLOCK_PRINT("raw_pread(%d:%s, %" PRId64 ", %p, %d) [%" PRId64

                              "] lseek failed : %d = %s\n",

                              s->fd, bs->filename, offset, buf, count,

                              bs->total_sectors, errno, strerror(errno));

        }

        return -1;

    }

    s->lseek_err_cnt=0;

    ret = read(s->fd, buf, count);

    if (ret == count)

        goto label__raw_read__success;

    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 (bs->type == BDRV_TYPE_CDROM) {

        lseek(s->fd, offset, SEEK_SET);

        ret = read(s->fd, buf, count);

        if (ret == count)

            goto label__raw_read__success;

        lseek(s->fd, offset, SEEK_SET);

        ret = read(s->fd, buf, count);

        if (ret == count)

            goto label__raw_read__success;

        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));

    }

label__raw_read__success:

    return ret;

}

/*

 * 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_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 ret;

    if (offset >= 0 && lseek(s->fd, offset, SEEK_SET) == (off_t)-1) {

        ++(s->lseek_err_cnt);

        if(s->lseek_err_cnt) {

            DEBUG_BLOCK_PRINT("raw_pwrite(%d:%s, %" PRId64 ", %p, %d) [%"

                              PRId64 "] lseek failed : %d = %s\n",

                              s->fd, bs->filename, offset, buf, count,

                              bs->total_sectors, errno, strerror(errno));

        }

        return -1;

    }

    s->lseek_err_cnt = 0;

    ret = write(s->fd, buf, count);

    if (ret == count)

        goto label__raw_write__success;

    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));

label__raw_write__success:

    return ret;

}

#if defined(O_DIRECT) && !defined(QEMU_IMG)

/*

 * 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;

    int size, ret, shift, sum;

    sum = 0;

    if (s->aligned_buf != NULL)  {

        if (offset & 0x1ff) {

            /* align offset on a 512 bytes boundary */

            shift = offset & 0x1ff;

            size = (shift + count + 0x1ff) & ~0x1ff;

            if (size > ALIGNED_BUFFER_SIZE)

                size = ALIGNED_BUFFER_SIZE;

            ret = raw_pread_aligned(bs, offset - shift, s->aligned_buf, size);

            if (ret < 0)

                return ret;

            size = 512 - 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 & 0x1ff || (uintptr_t) buf & 0x1ff) {

            /* read on aligned buffer */

            while (count) {

                size = (count + 0x1ff) & ~0x1ff;

                if (size > ALIGNED_BUFFER_SIZE)

                    size = ALIGNED_BUFFER_SIZE;

                ret = raw_pread_aligned(bs, offset, s->aligned_buf, size);

                if (ret < 0)

                    return ret;

                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;

}

/*

 * 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;

    int size, ret, shift, sum;

    sum = 0;

    if (s->aligned_buf != NULL) {

        if (offset & 0x1ff) {

            /* align offset on a 512 bytes boundary */

            shift = offset & 0x1ff;

            ret = raw_pread_aligned(bs, offset - shift, s->aligned_buf, 512);

            if (ret < 0)

                return ret;

            size = 512 - shift;

            if (size > count)

                size = count;

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

            ret = raw_pwrite_aligned(bs, offset - shift, s->aligned_buf, 512);

            if (ret < 0)

                return ret;

            buf += size;

            offset += size;

            count -= size;

            sum += size;

            if (count == 0)

                return sum;

        }

        if (count & 0x1ff || (uintptr_t) buf & 0x1ff) {

            while ((size = (count & ~0x1ff)) != 0) {

                if (size > ALIGNED_BUFFER_SIZE)

                    size = ALIGNED_BUFFER_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 < 512 because (count & ~0x1ff) == 0 */

            if (count) {

                ret = raw_pread_aligned(bs, offset, s->aligned_buf, 512);

                if (ret < 0)

                    return ret;

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

                 ret = raw_pwrite_aligned(bs, offset, s->aligned_buf, 512);

                 if (ret < 0)

                     return ret;

                 if (count < ret)

                     ret = count;

                 sum += ret;

            }

            return sum;

        }

    }

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

}

#else

#define raw_pread raw_pread_aligned

#define raw_pwrite raw_pwrite_aligned

#endif

#ifdef CONFIG_AIO

/***********************************************************/

/* Unix AIO using POSIX AIO */

typedef struct RawAIOCB {

    BlockDriverAIOCB common;

    struct aiocb aiocb;

    struct RawAIOCB *next;

    int ret;

} RawAIOCB;

static int aio_sig_num = SIGUSR2;

static RawAIOCB *first_aio; /* AIO issued */

static int aio_initialized = 0;

static void aio_signal_handler(int signum)

{

#if !defined(QEMU_IMG) && !defined(QEMU_NBD)

    CPUState *env = cpu_single_env;

    if (env) {

        /* stop the currently executing cpu because a timer occured */

        cpu_interrupt(env, CPU_INTERRUPT_EXIT);

#ifdef USE_KQEMU

        if (env->kqemu_enabled) {

            kqemu_cpu_interrupt(env);

        }

#endif

    }

#endif

}

void qemu_aio_init(void)

{

    struct sigaction act;

    aio_initialized = 1;

    sigfillset(&act.sa_mask);

    act.sa_flags = 0; /* do not restart syscalls to interrupt select() */

    act.sa_handler = aio_signal_handler;

    sigaction(aio_sig_num, &act, NULL);

#if defined(__GLIBC__) && defined(__linux__)

    {

        /* XXX: aio thread exit seems to hang on RedHat 9 and this init

           seems to fix the problem. */

        struct aioinit ai;

        memset(&ai, 0, sizeof(ai));

        ai.aio_threads = 1;

        ai.aio_num = 1;

        ai.aio_idle_time = 365 * 100000;

        aio_init(&ai);

    }

#endif

}

void qemu_aio_poll(void)

{

    RawAIOCB *acb, **pacb;

    int ret;

    for(;;) {

        pacb = &first_aio;

        for(;;) {

            acb = *pacb;

            if (!acb)

                goto the_end;

            ret = aio_error(&acb->aiocb);

            if (ret == ECANCELED) {

                /* remove the request */

                *pacb = acb->next;

                qemu_aio_release(acb);

            } else if (ret != EINPROGRESS) {

                /* end of aio */

                if (ret == 0) {

                    ret = aio_return(&acb->aiocb);

                    if (ret == acb->aiocb.aio_nbytes)

                        ret = 0;

                    else

                        ret = -EINVAL;

                } else {

                    ret = -ret;

                }

                /* remove the request */

                *pacb = acb->next;

                /* call the callback */

                acb->common.cb(acb->common.opaque, ret);

                qemu_aio_release(acb);

                break;

            } else {

                pacb = &acb->next;

            }

        }

    }

 the_end: ;

}

/* Wait for all IO requests to complete.  */

void qemu_aio_flush(void)

{

    qemu_aio_wait_start();

    qemu_aio_poll();

    while (first_aio) {

        qemu_aio_wait();

    }

    qemu_aio_wait_end();

}

/* wait until at least one AIO was handled */

static sigset_t wait_oset;

void qemu_aio_wait_start(void)

{

    sigset_t set;

    if (!aio_initialized)

        qemu_aio_init();

    sigemptyset(&set);

    sigaddset(&set, aio_sig_num);

    sigprocmask(SIG_BLOCK, &set, &wait_oset);

}

void qemu_aio_wait(void)

{

    sigset_t set;

    int nb_sigs;

#if !defined(QEMU_IMG) && !defined(QEMU_NBD)

    if (qemu_bh_poll())

        return;

#endif

    sigemptyset(&set);

    sigaddset(&set, aio_sig_num);

    sigwait(&set, &nb_sigs);

    qemu_aio_poll();

}

void qemu_aio_wait_end(void)

{

    sigprocmask(SIG_SETMASK, &wait_oset, NULL);

}

static RawAIOCB *raw_aio_setup(BlockDriverState *bs,

        int64_t sector_num, uint8_t *buf, int nb_sectors,

        BlockDriverCompletionFunc *cb, void *opaque)

{

    BDRVRawState *s = bs->opaque;

    RawAIOCB *acb;

    if (fd_open(bs) < 0)

        return NULL;

    acb = qemu_aio_get(bs, cb, opaque);

    if (!acb)

        return NULL;

    acb->aiocb.aio_fildes = s->fd;

    acb->aiocb.aio_sigevent.sigev_signo = aio_sig_num;

    acb->aiocb.aio_sigevent.sigev_notify = SIGEV_SIGNAL;

    acb->aiocb.aio_buf = buf;

    if (nb_sectors < 0)

        acb->aiocb.aio_nbytes = -nb_sectors;

    else

        acb->aiocb.aio_nbytes = nb_sectors * 512;

    acb->aiocb.aio_offset = sector_num * 512;

    acb->next = first_aio;

    first_aio = acb;

    return acb;

}

#if !defined(QEMU_IMG) && !defined(QEMU_NBD)

static void raw_aio_em_cb(void* opaque)

{

    RawAIOCB *acb = opaque;

    acb->common.cb(acb->common.opaque, acb->ret);

    qemu_aio_release(acb);

}

#endif

static BlockDriverAIOCB *raw_aio_read(BlockDriverState *bs,

        int64_t sector_num, uint8_t *buf, int nb_sectors,

        BlockDriverCompletionFunc *cb, void *opaque)

{

    RawAIOCB *acb;

    /*

     * If O_DIRECT is used and the buffer is not aligned fall back

     * to synchronous IO.

     */

#if defined(O_DIRECT) && !defined(QEMU_IMG) && !defined(QEMU_NBD)

    BDRVRawState *s = bs->opaque;

    if (unlikely(s->aligned_buf != NULL && ((uintptr_t) buf % 512))) {

        QEMUBH *bh;

        acb = qemu_aio_get(bs, cb, opaque);

        acb->ret = raw_pread(bs, 512 * sector_num, buf, 512 * nb_sectors);

        bh = qemu_bh_new(raw_aio_em_cb, acb);

        qemu_bh_schedule(bh);

        return &acb->common;

    }

#endif

    acb = raw_aio_setup(bs, sector_num, buf, nb_sectors, cb, opaque);

    if (!acb)

        return NULL;

    if (aio_read(&acb->aiocb) < 0) {

        qemu_aio_release(acb);

        return NULL;

    }

    return &acb->common;

}

static BlockDriverAIOCB *raw_aio_write(BlockDriverState *bs,

        int64_t sector_num, const uint8_t *buf, int nb_sectors,

        BlockDriverCompletionFunc *cb, void *opaque)

{

    RawAIOCB *acb;

    /*

     * If O_DIRECT is used and the buffer is not aligned fall back

     * to synchronous IO.

     */

#if defined(O_DIRECT) && !defined(QEMU_IMG) && !defined(QEMU_NBD)

    BDRVRawState *s = bs->opaque;

    if (unlikely(s->aligned_buf != NULL && ((uintptr_t) buf % 512))) {

        QEMUBH *bh;

        acb = qemu_aio_get(bs, cb, opaque);

        acb->ret = raw_pwrite(bs, 512 * sector_num, buf, 512 * nb_sectors);

        bh = qemu_bh_new(raw_aio_em_cb, acb);

        qemu_bh_schedule(bh);

        return &acb->common;

    }

#endif

    acb = raw_aio_setup(bs, sector_num, (uint8_t*)buf, nb_sectors, cb, opaque);

    if (!acb)

        return NULL;

    if (aio_write(&acb->aiocb) < 0) {

        qemu_aio_release(acb);

        return NULL;

    }

    return &acb->common;

}

static void raw_aio_cancel(BlockDriverAIOCB *blockacb)

{

    int ret;

    RawAIOCB *acb = (RawAIOCB *)blockacb;

    RawAIOCB **pacb;

    ret = aio_cancel(acb->aiocb.aio_fildes, &acb->aiocb);

    if (ret == AIO_NOTCANCELED) {

        /* fail safe: if the aio could not be canceled, we wait for

           it */

        while (aio_error(&acb->aiocb) == EINPROGRESS);

    }

    /* remove the callback from the queue */

    pacb = &first_aio;

    for(;;) {

        if (*pacb == NULL) {

            break;

        } else if (*pacb == acb) {

            *pacb = acb->next;

            qemu_aio_release(acb);

            break;

        }

        pacb = &acb->next;

    }

}

# else /* CONFIG_AIO */

void qemu_aio_init(void)

{

}

void qemu_aio_poll(void)

{

}

void qemu_aio_flush(void)

{

}

void qemu_aio_wait_start(void)

{

}

void qemu_aio_wait(void)

{

#if !defined(QEMU_IMG) && !defined(QEMU_NBD)

    qemu_bh_poll();

#endif

}

void qemu_aio_wait_end(void)

{

}

#endif /* CONFIG_AIO */

static void raw_close(BlockDriverState *bs)

{

    BDRVRawState *s = bs->opaque;

    if (s->fd >= 0) {

        close(s->fd);

        s->fd = -1;

#if defined(O_DIRECT) && !defined(QEMU_IMG)

        if (s->aligned_buf != NULL)

            qemu_free(s->aligned_buf);

#endif

    }

}

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;

}

static int64_t  raw_getlength(BlockDriverState *bs)

{

    BDRVRawState *s = bs->opaque;

    int fd = s->fd;

    int64_t size;

#ifdef _BSD

    struct stat sb;

#endif

#ifdef __sun__

    struct dk_minfo minfo;

    int rv;

#endif

    int ret;

    ret = fd_open(bs);

    if (ret < 0)

        return ret;

#ifdef _BSD

    if (!fstat(fd, &sb) && (S_IFCHR & sb.st_mode)) {

#ifdef DIOCGMEDIASIZE

        if (ioctl(fd, DIOCGMEDIASIZE, (off_t *)&size))

#endif

#ifdef CONFIG_COCOA

        size = LONG_LONG_MAX;

#else

        size = lseek(fd, 0LL, SEEK_END);

#endif

    } else

#endif

#ifdef __sun__

    /*

     * use the DKIOCGMEDIAINFO ioctl to read the size.

     */

    rv = ioctl ( fd, DKIOCGMEDIAINFO, &minfo );

    if ( rv != -1 ) {

        size = minfo.dki_lbsize * minfo.dki_capacity;

    } else /* there are reports that lseek on some devices

              fails, but irc discussion said that contingency

              on contingency was overkill */

#endif

    {

        size = lseek(fd, 0, SEEK_END);

    }

    return size;

}

static int raw_create(const char *filename, int64_t total_size,

                      const char *backing_file, int flags)

{

    int fd;

    if (flags || backing_file)

        return -ENOTSUP;

    fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,

              0644);

    if (fd < 0)

        return -EIO;

    ftruncate(fd, total_size * 512);

    close(fd);

    return 0;

}

static void raw_flush(BlockDriverState *bs)

{

    BDRVRawState *s = bs->opaque;

    fsync(s->fd);

}

BlockDriver bdrv_raw = {

    "raw",

    sizeof(BDRVRawState),

    NULL, /* no probe for protocols */

    raw_open,

    NULL,

    NULL,

    raw_close,

    raw_create,

    raw_flush,

#ifdef CONFIG_AIO

    .bdrv_aio_read = raw_aio_read,

    .bdrv_aio_write = raw_aio_write,

    .bdrv_aio_cancel = raw_aio_cancel,

    .aiocb_size = sizeof(RawAIOCB),

#endif

    .protocol_name = "file",

    .bdrv_pread = raw_pread,

    .bdrv_pwrite = raw_pwrite,

    .bdrv_truncate = raw_truncate,

    .bdrv_getlength = raw_getlength,

};

/***********************************************/

/* 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_open(BlockDriverState *bs, const char *filename, int flags)