block-raw.c

qemu性能直逼VMware的仿真器QEMU 的模擬速度約為實機的 25％；約為 Bochs 的 60 倍。Plex86、User-Mode-Linux、VMware 和 Virtual PC 則比

    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,
    
    .bdrv_aio_read = raw_aio_read,
    .bdrv_aio_write = raw_aio_write,
    .bdrv_aio_cancel = raw_aio_cancel,
    .aiocb_size = sizeof(RawAIOCB),
    .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)
{
    BDRVRawState *s = bs->opaque;
    int fd, open_flags, ret;

#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
    open_flags = O_BINARY;
    if ((flags & BDRV_O_ACCESS) == O_RDWR) {
        open_flags |= O_RDWR;
    } else {
        open_flags |= O_RDONLY;
        bs->read_only = 1;
    }

    s->type = FTYPE_FILE;
#if defined(__linux__)
    if (strstart(filename, "/dev/cd", NULL)) {
        /* open will not fail even if no CD is inserted */
        open_flags |= O_NONBLOCK;
        s->type = FTYPE_CD;
    } else if (strstart(filename, "/dev/fd", NULL)) {
        s->type = FTYPE_FD;
        s->fd_open_flags = open_flags;
        /* open will not fail even if no floppy is inserted */
        open_flags |= O_NONBLOCK;
    }
#endif
    fd = open(filename, open_flags, 0644);
    if (fd < 0) {
        ret = -errno;
        if (ret == -EROFS)
            ret = -EACCES;
        return ret;
    }
    s->fd = fd;
#if defined(__linux__)
    /* close fd so that we can reopen it as needed */
    if (s->type == FTYPE_FD) {
        close(s->fd);
        s->fd = -1;
        s->fd_media_changed = 1;
    }
#endif
    return 0;
}

#if defined(__linux__) && !defined(QEMU_TOOL)

/* 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 && 
        (qemu_get_clock(rt_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 && 
            (qemu_get_clock(rt_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->fd_open_flags);
        if (s->fd < 0) {
            s->fd_error_time = qemu_get_clock(rt_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 = qemu_get_clock(rt_clock);
    s->fd_got_error = 0;
    return 0;
}
#else
static int fd_open(BlockDriverState *bs)
{
    return 0;
}
#endif

#if defined(__linux__)

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

    switch(s->type) {
    case FTYPE_CD:
        ret = ioctl(s->fd, CDROM_DRIVE_STATUS, CDSL_CURRENT);
        if (ret == CDS_DISC_OK)
            return 1;
        else
            return 0;
        break;
    case FTYPE_FD:
        ret = fd_open(bs);
        return (ret >= 0);
    default:
        return 1;
    }
}

/* currently only used by fdc.c, but a CD version would be good too */
static int raw_media_changed(BlockDriverState *bs)
{
    BDRVRawState *s = bs->opaque;

    switch(s->type) {
    case FTYPE_FD:
        {
            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;
        }
    default:
        return -ENOTSUP;
    }
}

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

    switch(s->type) {
    case FTYPE_CD:
        if (eject_flag) {
            if (ioctl (s->fd, CDROMEJECT, NULL) < 0)
                perror("CDROMEJECT");
        } else {
            if (ioctl (s->fd, CDROMCLOSETRAY, NULL) < 0)
                perror("CDROMEJECT");
        }
        break;
    case FTYPE_FD:
        {
            int fd;
            if (s->fd >= 0) {
                close(s->fd);
                s->fd = -1;
            }
            fd = open(bs->filename, s->fd_open_flags | O_NONBLOCK);
            if (fd >= 0) {
                if (ioctl(fd, FDEJECT, 0) < 0)
                    perror("FDEJECT");
                close(fd);
            }
        }
        break;
    default:
        return -ENOTSUP;
    }
    return 0;
}

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

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

#else

static int raw_is_inserted(BlockDriverState *bs)
{
    return 1;
}

static int raw_media_changed(BlockDriverState *bs)
{
    return -ENOTSUP;
}

static int raw_eject(BlockDriverState *bs, int eject_flag)
{
    return -ENOTSUP;
}

static int raw_set_locked(BlockDriverState *bs, int locked)
{
    return -ENOTSUP;
}

#endif /* !linux */

BlockDriver bdrv_host_device = {
    "host_device",
    sizeof(BDRVRawState),
    NULL, /* no probe for protocols */
    hdev_open,
    NULL,
    NULL,
    raw_close,
    NULL,
    raw_flush,
    
    .bdrv_aio_read = raw_aio_read,
    .bdrv_aio_write = raw_aio_write,
    .bdrv_aio_cancel = raw_aio_cancel,
    .aiocb_size = sizeof(RawAIOCB),
    .bdrv_pread = raw_pread,
    .bdrv_pwrite = raw_pwrite,
    .bdrv_getlength = raw_getlength,

    /* removable device support */
    .bdrv_is_inserted = raw_is_inserted,
    .bdrv_media_changed = raw_media_changed,
    .bdrv_eject = raw_eject,
    .bdrv_set_locked = raw_set_locked,
};

#else /* _WIN32 */

/* XXX: use another file ? */
#include <winioctl.h>

#define FTYPE_FILE 0
#define FTYPE_CD     1
#define FTYPE_HARDDISK 2

typedef struct BDRVRawState {
    HANDLE hfile;
    int type;
    char drive_path[16]; /* format: "d:\" */
} BDRVRawState;

typedef struct RawAIOCB {
    BlockDriverAIOCB common;
    HANDLE hEvent;
    OVERLAPPED ov;
    int count;
} RawAIOCB;

int qemu_ftruncate64(int fd, int64_t length)
{
    LARGE_INTEGER li;
    LONG high;
    HANDLE h;
    BOOL res;

    if ((GetVersion() & 0x80000000UL) && (length >> 32) != 0)
	return -1;

    h = (HANDLE)_get_osfhandle(fd);

    /* get current position, ftruncate do not change position */
    li.HighPart = 0;
    li.LowPart = SetFilePointer (h, 0, &li.HighPart, FILE_CURRENT);
    if (li.LowPart == 0xffffffffUL && GetLastError() != NO_ERROR)
	return -1;

    high = length >> 32;
    if (!SetFilePointer(h, (DWORD) length, &high, FILE_BEGIN))
	return -1;
    res = SetEndOfFile(h);

    /* back to old position */
    SetFilePointer(h, li.LowPart, &li.HighPart, FILE_BEGIN);
    return res ? 0 : -1;
}

static int set_sparse(int fd)
{
    DWORD returned;
    return (int) DeviceIoControl((HANDLE)_get_osfhandle(fd), FSCTL_SET_SPARSE,
				 NULL, 0, NULL, 0, &returned, NULL);
}

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

    s->type = FTYPE_FILE;

    if ((flags & BDRV_O_ACCESS) == O_RDWR) {
        access_flags = GENERIC_READ | GENERIC_WRITE;
    } else {
        access_flags = GENERIC_READ;