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mirror of https://github.com/mpv-player/mpv synced 2024-12-15 19:35:49 +00:00
mpv/libmpdvdkit2/bsdi_ioctl.c
arpi b606cb1952 sync with libdvdcss 1.2.5 (including u8->uint8_t and whitespace cosmetics...)
patch by Andreas Hess <jaska@gmx.net>


git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@9334 b3059339-0415-0410-9bf9-f77b7e298cf2
2003-02-08 00:22:39 +00:00

771 lines
18 KiB
C

#include "config.h"
/*
* Hacked version of the linux cdrom.c kernel module - everything except the
* DVD handling ripped out and the rest rewritten to use raw SCSI commands
* on BSD/OS 4.2 (but should work with earlier versions as well).
*/
#include <sys/types.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include </sys/dev/scsi/scsi.h>
#include </sys/dev/scsi/scsi_ioctl.h>
#include "bsdi_dvd.h"
/*
* Now get rid of the override/intercept macro so we can call the real ioctl()
* routine!
*/
#undef ioctl
#define CMD_READ_10 0x28
#define CMD_READ_TOC_PMA_ATIP 0x43
#define CMD_READ_CD 0xbe
#define CMD_START_STOP_UNIT 0x1b
#define CMD_SEND_KEY 0xa3
#define CMD_REPORT_KEY 0xa4
#define CMD_READ_DVD_STRUCTURE 0xad
#define copy_key(dest,src) memcpy((dest), (src), sizeof(dvd_key))
#define copy_chal(dest,src) memcpy((dest), (src), sizeof(dvd_challenge))
/* Define the Cdrom Generic Command structure */
typedef struct cgc
{
u_char cdb[12];
u_char *buf;
int buflen;
int rw;
int timeout;
scsi_user_sense_t *sus;
} cgc_t;
static int scsi_cmd(int, cgc_t *);
static int cdrom_ioctl(int, u_long, void *);
static int cdrom_tray_move(int, int);
static void cdrom_count_tracks(int, tracktype *);
static int dvd_ioctl(int, u_long, void *);
static int debug = 0;
void dvd_cdrom_debug(int flag)
{
debug = flag;
}
/*
* This is the published entry point. Actually applications should simply
* include <dvd.h> and not refer to this at all.
*/
int dvd_cdrom_ioctl(int fd, unsigned long cmd, void *arg)
{
switch (cmd)
{
case DVD_AUTH:
case DVD_READ_STRUCT:
return(dvd_ioctl(fd, cmd, arg));
case CDROMREADTOCHDR:
case CDROMREADTOCENTRY:
case CDROMEJECT:
case CDROMREADRAW:
case CDROMREADMODE1:
case CDROMREADMODE2:
case CDROMCLOSETRAY:
case CDROM_DRIVE_STATUS:
case CDROM_DISC_STATUS:
return(cdrom_ioctl(fd, cmd, arg));
default:
return(ioctl(fd, cmd, arg));
}
}
static void setup_report_key(cgc_t *cgc, u_int agid, u_int type)
{
cgc->cdb[0] = CMD_REPORT_KEY;
cgc->cdb[10] = type | (agid << 6);
switch (type)
{
case 0:
case 5:
case 8:
cgc->buflen = 8;
break;
case 1:
cgc->buflen = 16;
break;
case 2:
case 4:
cgc->buflen = 12;
break;
}
cgc->cdb[9] = cgc->buflen;
cgc->rw = SUC_READ;;
}
static void setup_send_key(cgc_t *cgc, u_int agid, u_int type)
{
cgc->cdb[0] = CMD_SEND_KEY;
cgc->cdb[10] = type | (agid << 6);
switch (type)
{
case 1:
cgc->buflen = 16;
break;
case 3:
cgc->buflen = 12;
break;
case 6:
cgc->buflen = 8;
break;
}
cgc->cdb[9] = cgc->buflen;
cgc->rw = SUC_WRITE;
}
static void cgc_init(cgc_t *cgc, void *buf, int len, int type)
{
memset(cgc, 0, sizeof (*cgc));
if (buf)
memset(buf, 0, len);
cgc->buf = (u_char *)buf;
cgc->buflen = len;
cgc->rw = type;
cgc->timeout = 5; /* 5 second timeout */
}
static int dvd_do_auth(int fd, dvd_authinfo *ai)
{
int ret;
u_char buf[20];
cgc_t cgc;
rpc_state_t rpc_state;
memset(buf, 0, sizeof(buf));
cgc_init(&cgc, buf, 0, SUC_READ);
switch (ai->type)
{
case DVD_LU_SEND_AGID: /* LU data send */
setup_report_key(&cgc, ai->lsa.agid, 0);
if (ret = scsi_cmd(fd, &cgc))
return ret;
ai->lsa.agid = buf[7] >> 6;
break;
case DVD_LU_SEND_KEY1:
setup_report_key(&cgc, ai->lsk.agid, 2);
if (ret = scsi_cmd(fd, &cgc))
return ret;
copy_key(ai->lsk.key, &buf[4]);
break;
case DVD_LU_SEND_CHALLENGE:
setup_report_key(&cgc, ai->lsc.agid, 1);
if (ret = scsi_cmd(fd, &cgc))
return ret;
copy_chal(ai->lsc.chal, &buf[4]);
break;
case DVD_LU_SEND_TITLE_KEY: /* Post-auth key */
setup_report_key(&cgc, ai->lstk.agid, 4);
cgc.cdb[5] = ai->lstk.lba;
cgc.cdb[4] = ai->lstk.lba >> 8;
cgc.cdb[3] = ai->lstk.lba >> 16;
cgc.cdb[2] = ai->lstk.lba >> 24;
if (ret = scsi_cmd(fd, &cgc))
return ret;
ai->lstk.cpm = (buf[4] >> 7) & 1;
ai->lstk.cp_sec = (buf[4] >> 6) & 1;
ai->lstk.cgms = (buf[4] >> 4) & 3;
copy_key(ai->lstk.title_key, &buf[5]);
break;
case DVD_LU_SEND_ASF:
setup_report_key(&cgc, ai->lsasf.agid, 5);
if (ret = scsi_cmd(fd, &cgc))
return ret;
ai->lsasf.asf = buf[7] & 1;
break;
case DVD_HOST_SEND_CHALLENGE: /* LU data receive (LU changes state) */
setup_send_key(&cgc, ai->hsc.agid, 1);
buf[1] = 0xe;
copy_chal(&buf[4], ai->hsc.chal);
if (ret = scsi_cmd(fd, &cgc))
return ret;
ai->type = DVD_LU_SEND_KEY1;
break;
case DVD_HOST_SEND_KEY2:
setup_send_key(&cgc, ai->hsk.agid, 3);
buf[1] = 0xa;
copy_key(&buf[4], ai->hsk.key);
if (ret = scsi_cmd(fd, &cgc))
{
ai->type = DVD_AUTH_FAILURE;
return ret;
}
ai->type = DVD_AUTH_ESTABLISHED;
break;
case DVD_INVALIDATE_AGID:
setup_report_key(&cgc, ai->lsa.agid, 0x3f);
if (ret = scsi_cmd(fd, &cgc))
return ret;
break;
case DVD_LU_SEND_RPC_STATE: /* Get region settings */
setup_report_key(&cgc, 0, 8);
memset(&rpc_state, 0, sizeof(rpc_state_t));
cgc.buf = (char *) &rpc_state;
if (ret = scsi_cmd(fd, &cgc))
{
ai->lrpcs.type = 0;
ai->lrpcs.rpc_scheme = 0;
}
else
{
ai->lrpcs.type = rpc_state.type_code;
ai->lrpcs.vra = rpc_state.vra;
ai->lrpcs.ucca = rpc_state.ucca;
ai->lrpcs.region_mask = rpc_state.region_mask;
ai->lrpcs.rpc_scheme = rpc_state.rpc_scheme;
}
break;
case DVD_HOST_SEND_RPC_STATE: /* Set region settings */
setup_send_key(&cgc, 0, 6);
buf[1] = 6;
buf[4] = ai->hrpcs.pdrc;
if (ret = scsi_cmd(fd, &cgc))
return ret;
break;
default:
return EINVAL;
}
return 0;
}
static int dvd_read_physical(int fd, dvd_struct *s)
{
int ret, i;
u_char buf[4 + 4 * 20], *base;
struct dvd_layer *layer;
cgc_t cgc;
cgc_init(&cgc, buf, sizeof(buf), SUC_READ);
cgc.cdb[0] = CMD_READ_DVD_STRUCTURE;
cgc.cdb[6] = s->physical.layer_num;
cgc.cdb[7] = s->type;
cgc.cdb[9] = cgc.buflen & 0xff;
if (ret = scsi_cmd(fd, &cgc))
return ret;
base = &buf[4];
layer = &s->physical.layer[0];
/* place the data... really ugly, but at least we won't have to
worry about endianess in userspace or here. */
for (i = 0; i < 4; ++i, base += 20, ++layer)
{
memset(layer, 0, sizeof(*layer));
layer->book_version = base[0] & 0xf;
layer->book_type = base[0] >> 4;
layer->min_rate = base[1] & 0xf;
layer->disc_size = base[1] >> 4;
layer->layer_type = base[2] & 0xf;
layer->track_path = (base[2] >> 4) & 1;
layer->nlayers = (base[2] >> 5) & 3;
layer->track_density = base[3] & 0xf;
layer->linear_density = base[3] >> 4;
layer->start_sector = base[5] << 16 | base[6] << 8 | base[7];
layer->end_sector = base[9] << 16 | base[10] << 8 | base[11];
layer->end_sector_l0 = base[13] << 16 | base[14] << 8 | base[15];
layer->bca = base[16] >> 7;
}
return 0;
}
static int dvd_read_copyright(int fd, dvd_struct *s)
{
int ret;
u_char buf[8];
cgc_t cgc;
cgc_init(&cgc, buf, sizeof(buf), SUC_READ);
cgc.cdb[0] = CMD_READ_DVD_STRUCTURE;
cgc.cdb[6] = s->copyright.layer_num;
cgc.cdb[7] = s->type;
cgc.cdb[8] = cgc.buflen >> 8;
cgc.cdb[9] = cgc.buflen & 0xff;
if (ret = scsi_cmd(fd, &cgc))
return ret;
s->copyright.cpst = buf[4];
s->copyright.rmi = buf[5];
return 0;
}
static int dvd_read_disckey(int fd, dvd_struct *s)
{
int ret, size;
u_char *buf;
cgc_t cgc;
size = sizeof(s->disckey.value) + 4;
if ((buf = (u_char *) malloc(size)) == NULL)
return ENOMEM;
cgc_init(&cgc, buf, size, SUC_READ);
cgc.cdb[0] = CMD_READ_DVD_STRUCTURE;
cgc.cdb[7] = s->type;
cgc.cdb[8] = size >> 8;
cgc.cdb[9] = size & 0xff;
cgc.cdb[10] = s->disckey.agid << 6;
if (!(ret = scsi_cmd(fd, &cgc)))
memcpy(s->disckey.value, &buf[4], sizeof(s->disckey.value));
free(buf);
return ret;
}
static int dvd_read_bca(int fd, dvd_struct *s)
{
int ret;
u_char buf[4 + 188];
cgc_t cgc;
cgc_init(&cgc, buf, sizeof(buf), SUC_READ);
cgc.cdb[0] = CMD_READ_DVD_STRUCTURE;
cgc.cdb[7] = s->type;
cgc.cdb[9] = cgc.buflen = 0xff;
if (ret = scsi_cmd(fd, &cgc))
return ret;
s->bca.len = buf[0] << 8 | buf[1];
if (s->bca.len < 12 || s->bca.len > 188)
return EIO;
memcpy(s->bca.value, &buf[4], s->bca.len);
return 0;
}
static int dvd_read_manufact(int fd, dvd_struct *s)
{
int ret = 0, size;
u_char *buf;
cgc_t cgc;
size = sizeof(s->manufact.value) + 4;
if ((buf = (u_char *) malloc(size)) == NULL)
return ENOMEM;
cgc_init(&cgc, buf, size, SUC_READ);
cgc.cdb[0] = CMD_READ_DVD_STRUCTURE;
cgc.cdb[7] = s->type;
cgc.cdb[8] = size >> 8;
cgc.cdb[9] = size & 0xff;
if (ret = scsi_cmd(fd, &cgc))
{
free(buf);
return ret;
}
s->manufact.len = buf[0] << 8 | buf[1];
if (s->manufact.len < 0 || s->manufact.len > 2048)
ret = -EIO;
else
memcpy(s->manufact.value, &buf[4], s->manufact.len);
free(buf);
return ret;
}
static int dvd_read_struct(int fd, dvd_struct *s)
{
switch (s->type)
{
case DVD_STRUCT_PHYSICAL:
return dvd_read_physical(fd, s);
case DVD_STRUCT_COPYRIGHT:
return dvd_read_copyright(fd, s);
case DVD_STRUCT_DISCKEY:
return dvd_read_disckey(fd, s);
case DVD_STRUCT_BCA:
return dvd_read_bca(fd, s);
case DVD_STRUCT_MANUFACT:
return dvd_read_manufact(fd, s);
default:
return EINVAL;
}
}
static u_char scsi_cdblen[8] = {6, 10, 10, 12, 12, 12, 10, 10};
static int scsi_cmd(int fd, cgc_t *cgc)
{
int i, scsistatus, cdblen;
unsigned char *cp;
struct scsi_user_cdb suc;
/* safety checks */
if (cgc->rw != SUC_READ && cgc->rw != SUC_WRITE)
return(EINVAL);
suc.suc_flags = cgc->rw;
cdblen = scsi_cdblen[(cgc->cdb[0] >> 5) & 7];
suc.suc_cdblen = cdblen;
bcopy(cgc->cdb, suc.suc_cdb, cdblen);
suc.suc_data = cgc->buf;
suc.suc_datalen = cgc->buflen;
suc.suc_timeout = cgc->timeout;
if (ioctl(fd, SCSIRAWCDB, &suc) == -1)
return(errno);
scsistatus = suc.suc_sus.sus_status;
/*
* If the device returns a scsi sense error and debugging is enabled print
* some hopefully useful information on stderr.
*/
if (scsistatus && debug)
{
cp = suc.suc_sus.sus_sense;
fprintf(stderr,"scsistatus = %x cdb =",
scsistatus);
for (i = 0; i < cdblen; i++)
fprintf(stderr, " %x", cgc->cdb[i]);
fprintf(stderr, "\nsense =");
for (i = 0; i < 16; i++)
fprintf(stderr, " %x", cp[i]);
fprintf(stderr, "\n");
}
if (cgc->sus)
bcopy(&suc.suc_sus, cgc->sus, sizeof (struct scsi_user_sense));
if (scsistatus)
return(EIO); /* generic i/o error for unsuccessful status */
return(0);
}
/*
* The entry point for the DVDioctls for BSD/OS.
*/
static int dvd_ioctl(int fd, u_long cmd, void *arg)
{
int ret;
switch (cmd)
{
case DVD_READ_STRUCT:
ret = dvd_read_struct(fd, (dvd_struct *)arg);
if (ret)
errno = ret;
return(ret ? -1 : 0);
case DVD_AUTH:
ret = dvd_do_auth(fd, (dvd_authinfo *)arg);
if (ret)
errno = ret;
return(ret ? -1 : 0);
default:
errno = EINVAL;
return(-1);
}
}
/*
* The entry point for the CDROMioctls for BSD/OS
*/
static int cdrom_read_block(int, cgc_t *, int, int, int, int);
static int cdrom_read_cd(int, cgc_t *, int, int, int );
int cdrom_blocksize(int, int );
static inline
int msf_to_lba(char m, char s, char f)
{
return (((m * CD_SECS) + s) * CD_FRAMES + f) - CD_MSF_OFFSET;
}
cdrom_ioctl(int fd, u_long cmd, void *arg)
{
int ret;
cgc_t cgc;
switch (cmd)
{
case CDROMREADRAW:
case CDROMREADMODE1:
case CDROMREADMODE2:
{
struct cdrom_msf *msf;
int blocksize = 0, format = 0, lba;
switch (cmd)
{
case CDROMREADRAW:
blocksize = CD_FRAMESIZE_RAW;
break;
case CDROMREADMODE1:
blocksize = CD_FRAMESIZE;
format = 2;
break;
case CDROMREADMODE2:
blocksize = CD_FRAMESIZE_RAW0;
break;
}
msf = (struct cdrom_msf *)arg;
lba = msf_to_lba(msf->cdmsf_min0,msf->cdmsf_sec0,
msf->cdmsf_frame0);
ret = EINVAL;
if (lba < 0)
break;
cgc_init(&cgc, arg, blocksize, SUC_READ);
ret = cdrom_read_block(fd, &cgc, lba, 1, format, blocksize);
if (ret)
{
/*
* SCSI-II devices are not required to support CMD_READ_CD (which specifies
* the blocksize to read) so try switching the block size with a mode select,
* doing the normal read sector command and then changing the sector size back
* to 2048.
*
* If the program dies before changing the blocksize back sdopen()
* in the kernel will fail opens with a message that looks something like:
*
* "sr1: blksize 2336 not multiple of 512: cannot use"
*
* At that point the drive has to be power cycled (or reset in some other way).
*/
if (ret = cdrom_blocksize(fd, blocksize))
break;
ret = cdrom_read_cd(fd, &cgc, lba, blocksize, 1);
ret |= cdrom_blocksize(fd, 2048);
}
break;
}
case CDROMREADTOCHDR:
{
struct cdrom_tochdr *tochdr = (struct cdrom_tochdr *) arg;
u_char buffer[12];
cgc_init(&cgc, buffer, sizeof (buffer), SUC_READ);
cgc.cdb[0] = CMD_READ_TOC_PMA_ATIP;
cgc.cdb[1] = 0x2; /* MSF */
cgc.cdb[8] = 12; /* LSB of length */
ret = scsi_cmd(fd, &cgc);
if (!ret)
{
tochdr->cdth_trk0 = buffer[2];
tochdr->cdth_trk1 = buffer[3];
}
break;
}
case CDROMREADTOCENTRY:
{
struct cdrom_tocentry *tocentry = (struct cdrom_tocentry *) arg;
u_char buffer[12];
cgc_init(&cgc, buffer, sizeof (buffer), SUC_READ);
cgc.cdb[0] = CMD_READ_TOC_PMA_ATIP;
cgc.cdb[1] = (tocentry->cdte_format == CDROM_MSF) ? 0x02 : 0;
cgc.cdb[6] = tocentry->cdte_track;
cgc.cdb[8] = 12; /* LSB of length */
ret = scsi_cmd(fd, &cgc);
if (ret)
break;
tocentry->cdte_ctrl = buffer[5] & 0xf;
tocentry->cdte_adr = buffer[5] >> 4;
tocentry->cdte_datamode = (tocentry->cdte_ctrl & 0x04) ? 1 : 0;
if (tocentry->cdte_format == CDROM_MSF)
{
tocentry->cdte_addr.msf.minute = buffer[9];
tocentry->cdte_addr.msf.second = buffer[10];
tocentry->cdte_addr.msf.frame = buffer[11];
}
else
tocentry->cdte_addr.lba = (((((buffer[8] << 8)
+ buffer[9]) << 8)
+ buffer[10]) << 8)
+ buffer[11];
break;
}
case CDROMEJECT: /* NO-OP for now */
ret = cdrom_tray_move(fd, 1);
break;
case CDROMCLOSETRAY:
ret = cdrom_tray_move(fd, 0);
break;
/*
* This sucks but emulates the expected behaviour. Instead of the return
* value being the actual status a success/fail indicator should have been
* returned and the 3rd arg to the ioctl should have been an 'int *' to update
* with the actual status. Both the drive and disc status ioctl calls are
* similarily braindamaged.
*/
case CDROM_DRIVE_STATUS:
return(CDS_NO_INFO); /* XXX */
case CDROM_DISC_STATUS:
{
tracktype tracks;
int cnt;
cdrom_count_tracks(fd, &tracks);
if (tracks.error)
return(tracks.error);
if (tracks.audio > 0)
{
cnt = tracks.data + tracks.cdi + tracks.xa;
if (cnt == 0)
return(CDS_AUDIO);
else
return(CDS_MIXED);
}
if (tracks.cdi)
return(CDS_XA_2_2);
if (tracks.xa)
return(CDS_XA_2_1);
if (tracks.data)
return(CDS_DATA_1);
return(CDS_NO_INFO);
}
}
errno = ret;
return(ret ? -1 : 0);
}
static int cdrom_read_cd(int fd, cgc_t *cgc, int lba, int blocksize, int nblocks)
{
memset(&cgc->cdb, 0, sizeof(cgc->cdb));
cgc->cdb[0] = CMD_READ_10;
cgc->cdb[2] = (lba >> 24) & 0xff;
cgc->cdb[3] = (lba >> 16) & 0xff;
cgc->cdb[4] = (lba >> 8) & 0xff;
cgc->cdb[5] = lba & 0xff;
cgc->cdb[6] = (nblocks >> 16) & 0xff;
cgc->cdb[7] = (nblocks >> 8) & 0xff;
cgc->cdb[8] = nblocks & 0xff;
cgc->buflen = blocksize * nblocks;
return(scsi_cmd(fd, cgc));
}
static int cdrom_read_block(int fd, cgc_t *cgc,
int lba, int nblocks, int format, int blksize)
{
memset(&cgc->cdb, 0, sizeof(cgc->cdb));
cgc->cdb[0] = CMD_READ_CD;
/* expected sector size - cdda,mode1,etc. */
cgc->cdb[1] = format << 2;
/* starting address */
cgc->cdb[2] = (lba >> 24) & 0xff;
cgc->cdb[3] = (lba >> 16) & 0xff;
cgc->cdb[4] = (lba >> 8) & 0xff;
cgc->cdb[5] = lba & 0xff;
/* number of blocks */
cgc->cdb[6] = (nblocks >> 16) & 0xff;
cgc->cdb[7] = (nblocks >> 8) & 0xff;
cgc->cdb[8] = nblocks & 0xff;
cgc->buflen = blksize * nblocks;
/* set the header info returned */
switch (blksize)
{
case CD_FRAMESIZE_RAW0:
cgc->cdb[9] = 0x58;
break;
case CD_FRAMESIZE_RAW1:
cgc->cdb[9] = 0x78;
break;
case CD_FRAMESIZE_RAW:
cgc->cdb[9] = 0xf8;
break;
default:
cgc->cdb[9] = 0x10;
}
return(scsi_cmd(fd, cgc));
}
static void cdrom_count_tracks(int fd, tracktype *tracks)
{
struct cdrom_tochdr header;
struct cdrom_tocentry entry;
int ret, i;
bzero(tracks, sizeof (*tracks));
ret = cdrom_ioctl(fd, CDROMREADTOCHDR, &header);
/*
* This whole business is a crock anyhow so we don't bother distinguishing
* between no media, drive not ready, etc and on any error just say we have
* no info.
*/
if (ret)
{
tracks->error = CDS_NO_INFO;
return;
}
entry.cdte_format = CDROM_MSF;
for (i = header.cdth_trk0; i <= header.cdth_trk1; i++)
{
entry.cdte_track = i;
if (cdrom_ioctl(fd, CDROMREADTOCENTRY, &entry))
{
tracks->error = CDS_NO_INFO;
return;
}
if (entry.cdte_ctrl & CDROM_DATA_TRACK)
{
if (entry.cdte_format == 0x10)
tracks->cdi++;
else if (entry.cdte_format == 0x20)
tracks->xa++;
else
tracks->data++;
}
else
tracks->audio++;
}
return;
}
static int cdrom_tray_move(int fd, int flag)
{
cgc_t cgc;
cgc_init(&cgc, NULL, 0, SUC_READ);
cgc.cdb[0] = CMD_START_STOP_UNIT;
cgc.cdb[1] = 1; /* immediate */
cgc.cdb[4] = flag ? 0x2 : 0x3; /* eject : close */
return(scsi_cmd(fd, &cgc));
}
/*
* Required when we need to use READ_10 to issue other than 2048 block
* reads
*/
int cdrom_blocksize(int fd, int size)
{
cgc_t cgc;
struct modesel_head mh;
memset(&mh, 0, sizeof(mh));
mh.block_desc_length = 0x08;
mh.block_length_med = (size >> 8) & 0xff;
mh.block_length_lo = size & 0xff;
memset(&cgc, 0, sizeof(cgc));
cgc.cdb[0] = 0x15;
cgc.cdb[1] = 1 << 4;
cgc.cdb[4] = 12;
cgc.buflen = sizeof(mh);
cgc.buf = (u_char *) &mh;
cgc.rw = SUC_WRITE;
mh.block_desc_length = 0x08;
mh.block_length_med = (size >> 8) & 0xff;
mh.block_length_lo = size & 0xff;
return(scsi_cmd(fd, &cgc));
}