src/disk/diskimage_scsicmd.c

/*
 *  Copyright (C) 2003-2007  Anders Gavare.  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright  
 *     notice, this list of conditions and the following disclaimer in the 
 *     documentation and/or other materials provided with the distribution.
 *  3. The name of the author may not be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 *  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 *  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE   
 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 *  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 *  OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 *  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 *  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 *  OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 *  SUCH DAMAGE.
 *
 *
 *  $Id: diskimage_scsicmd.c,v 1.2 2007/03/24 04:05:34 debug Exp $
 *
 *  Disk image support: SCSI command emulation.
 *
 *  TODO:  There are LOTS of ugly magic values in this module. These should
 *         be replaced by proper defines.
 *
 *  TODO:  There's probably a bug in the tape support:
 *         Let's say there are 10240 bytes left in a file, and 10240
 *         bytes are read. Then feof() is not true yet (?), so the next
 *         read will also return 10240 bytes (but all zeroes), and then after
 *         that return feof (which results in a filemark).  This is probably
 *         trivial to fix, but I don't feel like it right now.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "cpu.h"
#include "diskimage.h"
#include "machine.h"
#include "misc.h"


static char *diskimage_types[] = DISKIMAGE_TYPES;
static struct scsi_transfer *first_free_scsi_transfer_alloc = NULL;


/*
 *  scsi_transfer_alloc():
 *
 *  Allocates memory for a new scsi_transfer struct, and fills it with
 *  sane data (NULL pointers).
 *  The return value is a pointer to the new struct.  If allocation
 *  failed, the program exits.
 */
struct scsi_transfer *scsi_transfer_alloc(void)
{
        struct scsi_transfer *p;

        if (first_free_scsi_transfer_alloc != NULL) {
                p = first_free_scsi_transfer_alloc;
                first_free_scsi_transfer_alloc = p->next_free;
        } else {
                p = malloc(sizeof(struct scsi_transfer));
                if (p == NULL) {
                        fprintf(stderr, "scsi_transfer_alloc(): out "
                            "of memory\n");
                        exit(1);
                }
        }

        memset(p, 0, sizeof(struct scsi_transfer));

        return p;
}


/*
 *  scsi_transfer_free():
 *
 *  Frees the space used by a scsi_transfer struct.  All buffers refered
 *  to by the scsi_transfer struct are freed.
 */
void scsi_transfer_free(struct scsi_transfer *p)
{
        if (p == NULL) {
                fprintf(stderr, "scsi_transfer_free(): p == NULL\n");
                exit(1);
        }

        if (p->msg_out != NULL)
                free(p->msg_out);
        if (p->cmd != NULL)
                free(p->cmd);
        if (p->data_out != NULL)
                free(p->data_out);

        if (p->data_in != NULL)
                free(p->data_in);
        if (p->msg_in != NULL)
                free(p->msg_in);
        if (p->status != NULL)
                free(p->status);

        p->next_free = first_free_scsi_transfer_alloc;
        first_free_scsi_transfer_alloc = p;
}


/*
 *  scsi_transfer_allocbuf():
 *
 *  Helper function, used by diskimage_scsicommand(), and SCSI controller
 *  devices.  Example of usage:
 *
 *      scsi_transfer_allocbuf(&xferp->msg_in_len, &xferp->msg_in, 1);
 */
void scsi_transfer_allocbuf(size_t *lenp, unsigned char **pp, size_t want_len,
        int clearflag)
{
        unsigned char *p = (*pp);

        if (p != NULL) {
                printf("WARNING! scsi_transfer_allocbuf(): old pointer "
                    "was not NULL, freeing it now\n");
                free(p);
        }

        (*lenp) = want_len;
        if ((p = malloc(want_len)) == NULL) {
                fprintf(stderr, "scsi_transfer_allocbuf(): out of "
                    "memory trying to allocate %li bytes\n", (long)want_len);
                exit(1);
        }

        if (clearflag)
                memset(p, 0, want_len);

        (*pp) = p;
}


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


/*
 *  diskimage__return_default_status_and_message():
 *
 *  Set the status and msg_in parts of a scsi_transfer struct
 *  to default values (msg_in = 0x00, status = 0x00).
 */
static void diskimage__return_default_status_and_message(
        struct scsi_transfer *xferp)
{
        scsi_transfer_allocbuf(&xferp->status_len, &xferp->status, 1, 0);
        xferp->status[0] = 0x00;
        scsi_transfer_allocbuf(&xferp->msg_in_len, &xferp->msg_in, 1, 0);
        xferp->msg_in[0] = 0x00;
}


/*
 *  diskimage__switch_tape():
 *
 *  Used by the SPACE command.  (d is assumed to be non-NULL.)
 */
static void diskimage__switch_tape(struct diskimage *d)
{
        char tmpfname[1000];

        snprintf(tmpfname, sizeof(tmpfname), "%s.%i",
            d->fname, d->tape_filenr);
        tmpfname[sizeof(tmpfname)-1] = '\0';

        if (d->f != NULL)
                fclose(d->f);

        d->f = fopen(tmpfname, d->writable? "r+" : "r");
        if (d->f == NULL) {
                fprintf(stderr, "[ diskimage__switch_tape(): could not "
                    "(re)open '%s' ]\n", tmpfname);
                /*  TODO: return error  */
        }
        d->tape_offset = 0;
}


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


/*
 *  diskimage_scsicommand():
 *
 *  Perform a SCSI command on a disk image.
 *
 *  The xferp points to a scsi_transfer struct, containing msg_out, command,
 *  and data_out coming from the SCSI controller device.  This function
 *  interprets the command, and (if necessary) creates responses in
 *  data_in, msg_in, and status.
 *
 *  Returns:
 *      2 if the command expects data from the DATA_OUT phase,
 *      1 if otherwise ok,
 *      0 on error.
 */
int diskimage_scsicommand(struct cpu *cpu, int id, int type,
        struct scsi_transfer *xferp)
{
        char namebuf[16];
        int retlen, i, q;
        uint64_t size;
        int64_t ofs;
        int pagecode;
        struct machine *machine = cpu->machine;
        struct diskimage *d;

        if (machine == NULL) {
                fatal("[ diskimage_scsicommand(): machine == NULL ]\n");
                return 0;
        }

        d = machine->first_diskimage;
        while (d != NULL) {
                if (d->type == type && d->id == id)
                        break;
                d = d->next;
        }
        if (d == NULL) {
                fprintf(stderr, "[ diskimage_scsicommand(): %s "
                    " id %i not connected? ]\n", diskimage_types[type], id);
        }

        if (xferp->cmd == NULL) {
                fatal("[ diskimage_scsicommand(): cmd == NULL ]\n");
                return 0;
        }

        if (xferp->cmd_len < 1) {
                fatal("[ diskimage_scsicommand(): cmd_len == %i ]\n",
                    xferp->cmd_len);
                return 0;
        }

        debug("[ diskimage_scsicommand(id=%i) cmd=0x%02x: ",
            id, xferp->cmd[0]);

#if 0
        fatal("[ diskimage_scsicommand(id=%i) cmd=0x%02x len=%i:",
            id, xferp->cmd[0], xferp->cmd_len);
        for (i=0; i<xferp->cmd_len; i++)
                fatal(" %02x", xferp->cmd[i]);
        fatal("\n");
if (xferp->cmd_len > 7 && xferp->cmd[5] == 0x11)
        single_step = ENTER_SINGLE_STEPPING;
#endif

#if 0
{
        static FILE *f = NULL;
        if (f == NULL)
                f = fopen("scsi_log.txt", "w"); 
        if (f != NULL) {
                int i;
                fprintf(f, "id=%i cmd =", id);
                for (i=0; i<xferp->cmd_len; i++)
                        fprintf(f, " %02x", xferp->cmd[i]);
                fprintf(f, "\n");
                fflush(f);
        }
}
#endif

        switch (xferp->cmd[0]) {

        case SCSICMD_TEST_UNIT_READY:
                debug("TEST_UNIT_READY");
                if (xferp->cmd_len != 6)
                        debug(" (weird len=%i)", xferp->cmd_len);

                /*  TODO: bits 765 of buf[1] contains the LUN  */
                if (xferp->cmd[1] != 0x00)
                        fatal("WARNING: TEST_UNIT_READY with cmd[1]=0x%02x"
                            " not yet implemented\n", (int)xferp->cmd[1]);

                diskimage__return_default_status_and_message(xferp);
                break;

        case SCSICMD_INQUIRY:
                debug("INQUIRY");
                if (xferp->cmd_len != 6)
                        debug(" (weird len=%i)", xferp->cmd_len);
                if (xferp->cmd[1] != 0x00) {
                        debug("WARNING: INQUIRY with cmd[1]=0x%02x not yet "
                            "implemented\n", (int)xferp->cmd[1]);

                        break;
                }

                /*  Return values:  */
                retlen = xferp->cmd[4];
                if (retlen < 36) {
                        fatal("WARNING: SCSI inquiry len=%i, <36!\n", retlen);
                        retlen = 36;
                }

                /*  Return data:  */
                scsi_transfer_allocbuf(&xferp->data_in_len, &xferp->data_in,
                    retlen, 1);
                xferp->data_in[0] = 0x00;  /*  0x00 = Direct-access disk  */
                xferp->data_in[1] = 0x00;  /*  0x00 = non-removable  */
                xferp->data_in[2] = 0x02;  /*  SCSI-2  */
#if 0
xferp->data_in[3] = 0x02;       /*  Response data format = SCSI-2  */
#endif
                xferp->data_in[4] = retlen - 4; /*  Additional length  */
xferp->data_in[4] = 0x2c - 4;   /*  Additional length  */
                xferp->data_in[6] = 0x04;  /*  ACKREQQ  */
                xferp->data_in[7] = 0x60;  /*  WBus32, WBus16  */

                /*  These are padded with spaces:  */

                memcpy(xferp->data_in+8,  "GXemul  ", 8);
                if (diskimage_getname(cpu->machine, id,
                    type, namebuf, sizeof(namebuf))) {
                        size_t i;
                        for (i=0; i<sizeof(namebuf); i++)
                                if (namebuf[i] == 0) {
                                        for (; i<sizeof(namebuf); i++)
                                                namebuf[i] = ' ';
                                        break;
                                }
                        memcpy(xferp->data_in+16, namebuf, 16);
                } else
                        memcpy(xferp->data_in+16, "DISK            ", 16);
                memcpy(xferp->data_in+32, "0   ", 4);

                /*
                 *  Some Ultrix kernels want specific responses from
                 *  the drives.
                 */

                if (machine->machine_type == MACHINE_PMAX) {
                        /*  DEC, RZ25 (rev 0900) = 832527 sectors  */
                        /*  DEC, RZ58 (rev 2000) = 2698061 sectors  */
                        memcpy(xferp->data_in+8,  "DEC     ", 8);
                        memcpy(xferp->data_in+16, "RZ58     (C) DEC", 16);
                        memcpy(xferp->data_in+32, "2000", 4);
                }

                /*  Some data is different for CD-ROM drives:  */
                if (d->is_a_cdrom) {
                        xferp->data_in[0] = 0x05;  /*  0x05 = CD-ROM  */
                        xferp->data_in[1] = 0x80;  /*  0x80 = removable  */
                        /*  memcpy(xferp->data_in+16, "CD-ROM          ", 16);*/

                        if (machine->machine_type == MACHINE_PMAX) {
                                /*  SONY, CD-ROM:  */
                                memcpy(xferp->data_in+8, "SONY    ", 8);
                                memcpy(xferp->data_in+16,
                                    "CD-ROM          ", 16);

                                /*  ... or perhaps this:  */
                                memcpy(xferp->data_in+8, "DEC     ", 8);
                                memcpy(xferp->data_in+16,
                                    "RRD42   (C) DEC ", 16);
                                memcpy(xferp->data_in+32, "4.5d", 4);
                        } else if (machine->machine_type == MACHINE_ARC) {
                                /*  NEC, CD-ROM:  */
                                memcpy(xferp->data_in+8, "NEC     ", 8);
                                memcpy(xferp->data_in+16,
                                    "CD-ROM CDR-210P ", 16);
                                memcpy(xferp->data_in+32, "1.0 ", 4);
                        }
                }

                /*  Data for tape devices:  */
                if (d->is_a_tape) {
                        xferp->data_in[0] = 0x01;  /*  0x01 = tape  */
                        xferp->data_in[1] = 0x80;  /*  0x80 = removable  */
                        memcpy(xferp->data_in+16, "TAPE            ", 16);

                        if (machine->machine_type == MACHINE_PMAX) {
                                /*
                                 *  TODO:  find out if these are correct.
                                 *
                                 *  The name might be TZK10, TSZ07, or TLZ04,
                                 *  or something completely different.
                                 */
                                memcpy(xferp->data_in+8, "DEC     ", 8);
                                memcpy(xferp->data_in+16,
                                    "TK50     (C) DEC", 16);
                                memcpy(xferp->data_in+32, "2000", 4);
                        }
                }

                diskimage__return_default_status_and_message(xferp);
                break;

        case SCSIBLOCKCMD_READ_CAPACITY:
                debug("READ_CAPACITY");

                if (xferp->cmd_len != 10)
                        fatal(" [ weird READ_CAPACITY len=%i, should be 10 ] ",
                            xferp->cmd_len);
                else {
                        if (xferp->cmd[8] & 1) {
                                /*  Partial Medium Indicator bit...  TODO  */
                                fatal("WARNING: READ_CAPACITY with PMI bit"
                                    " set not yet implemented\n");
                        }
                }

                /*  Return data:  */
                scsi_transfer_allocbuf(&xferp->data_in_len, &xferp->data_in,
                    8, 1);

                diskimage_recalc_size(d);

                size = d->total_size / d->logical_block_size;
                if (d->total_size & (d->logical_block_size-1))
                        size ++;

                xferp->data_in[0] = (size >> 24) & 255;
                xferp->data_in[1] = (size >> 16) & 255;
                xferp->data_in[2] = (size >> 8) & 255;
                xferp->data_in[3] = size & 255;

                xferp->data_in[4] = (d->logical_block_size >> 24) & 255;
                xferp->data_in[5] = (d->logical_block_size >> 16) & 255;
                xferp->data_in[6] = (d->logical_block_size >> 8) & 255;
                xferp->data_in[7] = d->logical_block_size & 255;

                diskimage__return_default_status_and_message(xferp);
                break;

        case SCSICMD_MODE_SENSE:
        case SCSICMD_MODE_SENSE10:      
                debug("MODE_SENSE");
                q = 4; retlen = xferp->cmd[4];
                switch (xferp->cmd_len) {
                case 6: break;
                case 10:q = 8;
                        retlen = xferp->cmd[7] * 256 + xferp->cmd[8];
                        break;
                default:fatal(" (unimplemented mode_sense len=%i)",
                            xferp->cmd_len);
                }

                /*
                 *  NOTE/TODO: This code doesn't handle too short retlens
                 *  very well. A quick hack around this is that I allocate
                 *  a bit too much memory, so that nothing is actually
                 *  written outside of xferp->data_in[].
                 */

                retlen += 100;          /*  Should be enough. (Ugly.)  */

                if ((xferp->cmd[2] & 0xc0) != 0)
                        fatal("WARNING: mode sense, cmd[2] = 0x%02x\n",
                            xferp->cmd[2]);

                /*  Return data:  */
                scsi_transfer_allocbuf(&xferp->data_in_len,
                    &xferp->data_in, retlen, 1);

                xferp->data_in_len -= 100;      /*  Restore size.  */

                pagecode = xferp->cmd[2] & 0x3f;

                debug("[ MODE SENSE id %i, pagecode=%i ]\n", id, pagecode);

                /*  4 bytes of header for 6-byte command,
                    8 bytes of header for 10-byte command.  */
                xferp->data_in[0] = retlen;     /*  0: mode data length  */
                xferp->data_in[1] = d->is_a_cdrom? 0x05 : 0x00;
                                /*  1: medium type  */
                xferp->data_in[2] = 0x00;       /*  device specific
                                                    parameter  */
                xferp->data_in[3] = 8 * 1;      /*  block descriptor
                                                    length: 1 page (?)  */

                xferp->data_in[q+0] = 0x00;     /*  density code  */
                xferp->data_in[q+1] = 0;        /*  nr of blocks, high  */
                xferp->data_in[q+2] = 0;        /*  nr of blocks, mid  */
                xferp->data_in[q+3] = 0;        /*  nr of blocks, low */
                xferp->data_in[q+4] = 0x00;     /*  reserved  */
                xferp->data_in[q+5] = (d->logical_block_size >> 16) & 255;
                xferp->data_in[q+6] = (d->logical_block_size >> 8) & 255;
                xferp->data_in[q+7] = d->logical_block_size & 255;
                q += 8;

                diskimage__return_default_status_and_message(xferp);

                /*  descriptors, 8 bytes (each)  */

                /*  page, n bytes (each)  */
                switch (pagecode) {
                case 0:
                        /*  TODO: Nothing here?  */
                        break;
                case 1:         /*  read-write error recovery page  */
                        xferp->data_in[q + 0] = pagecode;
                        xferp->data_in[q + 1] = 10;
                        break;
                case 3:         /*  format device page  */
                        xferp->data_in[q + 0] = pagecode;
                        xferp->data_in[q + 1] = 22;

                        /*  10,11 = sectors per track  */
                        xferp->data_in[q + 10] = 0;
                        xferp->data_in[q + 11] = d->sectors_per_track;

                        /*  12,13 = physical sector size  */
                        xferp->data_in[q + 12] =
                            (d->logical_block_size >> 8) & 255;
                        xferp->data_in[q + 13] = d->logical_block_size & 255;
                        break;
                case 4:         /*  rigid disk geometry page  */
                        xferp->data_in[q + 0] = pagecode;
                        xferp->data_in[q + 1] = 22;
                        xferp->data_in[q + 2] = (d->ncyls >> 16) & 255;
                        xferp->data_in[q + 3] = (d->ncyls >> 8) & 255;
                        xferp->data_in[q + 4] = d->ncyls & 255;
                        xferp->data_in[q + 5] = d->heads;

                        xferp->data_in[q + 20] = (d->rpms >> 8) & 255;
                        xferp->data_in[q + 21] = d->rpms & 255;
                        break;
                case 5:         /*  flexible disk page  */
                        xferp->data_in[q + 0] = pagecode;
                        xferp->data_in[q + 1] = 0x1e;

                        /*  2,3 = transfer rate  */
                        xferp->data_in[q + 2] = ((5000) >> 8) & 255;
                        xferp->data_in[q + 3] = (5000) & 255;

                        xferp->data_in[q + 4] = d->heads;
                        xferp->data_in[q + 5] = d->sectors_per_track;

                        /*  6,7 = data bytes per sector  */
                        xferp->data_in[q + 6] = (d->logical_block_size >> 8)
                            & 255;
                        xferp->data_in[q + 7] = d->logical_block_size & 255;

                        xferp->data_in[q + 8] = (d->ncyls >> 8) & 255;
                        xferp->data_in[q + 9] = d->ncyls & 255;

                        xferp->data_in[q + 28] = (d->rpms >> 8) & 255;
                        xferp->data_in[q + 29] = d->rpms & 255;
                        break;
                default:
                        fatal("[ MODE_SENSE for page %i is not yet "
                            "implemented! ]\n", pagecode);
                }

                break;

        case SCSICMD_READ:
        case SCSICMD_READ_10:
                debug("READ");

                /*
                 *  For tape devices, read data at the current position.
                 *  For disk and CDROM devices, the command bytes contain
                 *  an offset telling us where to read from the device.
                 */

                if (d->is_a_tape) {
                        /*  bits 7..5 of cmd[1] are the LUN bits... TODO  */

                        size = (xferp->cmd[2] << 16) +
                               (xferp->cmd[3] <<  8) +
                                xferp->cmd[4];

                        /*  Bit 1 of cmd[1] is the SILI bit (TODO), and
                            bit 0 is the "use fixed length" bit.  */

                        if (xferp->cmd[1] & 0x01) {
                                /*  Fixed block length:  */
                                size *= d->logical_block_size;
                        }

                        if (d->filemark) {
                                /*  At end of file, switch to the next
                                    automagically:  */
                                d->tape_filenr ++;
                                diskimage__switch_tape(d);

                                d->filemark = 0;
                        }

                        ofs = d->tape_offset;

                        fatal("[ READ tape, id=%i file=%i, cmd[1]=%02x size=%i"
                            ", ofs=%lli ]\n", id, d->tape_filenr,
                            xferp->cmd[1], (int)size, (long long)ofs);
                } else {
                        if (xferp->cmd[0] == SCSICMD_READ) {
                                if (xferp->cmd_len != 6)
                                        debug(" (weird len=%i)",
                                            xferp->cmd_len);

                                /*
                                 *  bits 4..0 of cmd[1], and cmd[2] and cmd[3]
                                 *  hold the logical block address.
                                 *
                                 *  cmd[4] holds the number of logical blocks
                                 *  to transfer. (Special case if the value is
                                 *  0, actually means 256.)
                                 */
                                ofs = ((xferp->cmd[1] & 0x1f) << 16) +
                                      (xferp->cmd[2] << 8) + xferp->cmd[3];
                                retlen = xferp->cmd[4];
                                if (retlen == 0)
                                        retlen = 256;
                        } else {
                                if (xferp->cmd_len != 10)
                                        debug(" (weird len=%i)",
                                            xferp->cmd_len);

                                /*
                                 *  cmd[2..5] hold the logical block address.
                                 *  cmd[7..8] holds the number of logical
                                 *  blocks to transfer. (NOTE: If the value is
                                 *  0, this means 0, not 65536. :-)
                                 */
                                ofs = ((uint64_t)xferp->cmd[2] << 24) +
                                    (xferp->cmd[3] << 16) + (xferp->cmd[4] << 8)
                                    + xferp->cmd[5];
                                retlen = (xferp->cmd[7] << 8) + xferp->cmd[8];
                        }

                        size = retlen * d->logical_block_size;
                        ofs *= d->logical_block_size;
                }

                /*  Return data:  */
                scsi_transfer_allocbuf(&xferp->data_in_len, &xferp->data_in,
                    size, 0);

                debug(" READ  ofs=%lli size=%i\n", (long long)ofs, (int)size);

                diskimage__return_default_status_and_message(xferp);

                d->filemark = 0;

                /*
                 *  Failure? Then set check condition.
                 *  For tapes, error should only occur at the end of a file.
                 *
                 *  "If the logical unit encounters a filemark during
                 *   a READ command, CHECK CONDITION status shall be
                 *   returned and the filemark and valid bits shall be
                 *   set to one in the sense data. The sense key shall
                 *   be set to NO SENSE"..
                 */
                if (d->is_a_tape && d->f != NULL && feof(d->f)) {
                        debug(" feof id=%i\n", id);
                        xferp->status[0] = 0x02;        /*  CHECK CONDITION  */

                        d->filemark = 1;
                } else
                        diskimage__internal_access(d, 0, ofs,
                            xferp->data_in, size);

                if (d->is_a_tape && d->f != NULL)
                        d->tape_offset = ftello(d->f);

                /*  TODO: other errors?  */
                break;

        case SCSICMD_WRITE:
        case SCSICMD_WRITE_10:
                debug("WRITE");

                /*  TODO: tape  */

                if (xferp->cmd[0] == SCSICMD_WRITE) {
                        if (xferp->cmd_len != 6)
                                debug(" (weird len=%i)", xferp->cmd_len);

                        /*
                         *  bits 4..0 of cmd[1], and cmd[2] and cmd[3] hold the
                         *  logical block address.
                         *
                         *  cmd[4] holds the number of logical blocks to
                         *  transfer. (Special case if the value is 0, actually
                         *  means 256.)
                         */
                        ofs = ((xferp->cmd[1] & 0x1f) << 16) +
                              (xferp->cmd[2] << 8) + xferp->cmd[3];
                        retlen = xferp->cmd[4];
                        if (retlen == 0)
                                retlen = 256;
                } else {
                        if (xferp->cmd_len != 10)
                                debug(" (weird len=%i)", xferp->cmd_len);

                        /*
                         *  cmd[2..5] hold the logical block address.
                         *  cmd[7..8] holds the number of logical blocks to
                         *  transfer. (NOTE: If the value is 0 this means 0,
                         *  not 65536.)
                         */
                        ofs = ((uint64_t)xferp->cmd[2] << 24) +
                            (xferp->cmd[3] << 16) + (xferp->cmd[4] << 8) +
                            xferp->cmd[5];
                        retlen = (xferp->cmd[7] << 8) + xferp->cmd[8];
                }

                size = retlen * d->logical_block_size;
                ofs *= d->logical_block_size;

                if (xferp->data_out_offset != size) {
                        debug(", data_out == NULL, wanting %i bytes, \n\n",
                            (int)size);
                        xferp->data_out_len = size;
                        return 2;
                }

                debug(", data_out != NULL, OK :-)");

                debug("WRITE ofs=%i size=%i offset=%i\n", (int)ofs,
                    (int)size, (int)xferp->data_out_offset);

                diskimage__internal_access(d, 1, ofs,
                    xferp->data_out, size);

                /*  TODO: how about return code?  */

                /*  Is this really necessary?  */
                /*  fsync(fileno(d->f));  */

                diskimage__return_default_status_and_message(xferp);
                break;

        case SCSICMD_SYNCHRONIZE_CACHE:
                debug("SYNCHRONIZE_CACHE");

                if (xferp->cmd_len != 10)
                        debug(" (weird len=%i)", xferp->cmd_len);

                /*  TODO: actualy care about cmd[]  */
                fsync(fileno(d->f));

                diskimage__return_default_status_and_message(xferp);
                break;

        case SCSICMD_START_STOP_UNIT:
                debug("START_STOP_UNIT");

                if (xferp->cmd_len != 6)
                        debug(" (weird len=%i)", xferp->cmd_len);

                for (i=0; i<(ssize_t)xferp->cmd_len; i++)
                        debug(" %02x", xferp->cmd[i]);

                /*  TODO: actualy care about cmd[]  */

                diskimage__return_default_status_and_message(xferp);
                break;

        case SCSICMD_REQUEST_SENSE:
                debug("REQUEST_SENSE");

                retlen = xferp->cmd[4];

                /*  TODO: bits 765 of buf[1] contains the LUN  */
                if (xferp->cmd[1] != 0x00)
                        fatal("WARNING: REQUEST_SENSE with cmd[1]=0x%02x not"
                            " yet implemented\n", (int)xferp->cmd[1]);

                if (retlen < 18) {
                        fatal("WARNING: SCSI request sense len=%i, <18!\n",
                            (int)retlen);
                        retlen = 18;
                }

                /*  Return data:  */
                scsi_transfer_allocbuf(&xferp->data_in_len, &xferp->data_in,
                    retlen, 1);

                xferp->data_in[0] = 0x80 + 0x70;/*  0x80 = valid,
                                                    0x70 = "current errors"  */
                xferp->data_in[2] = 0x00;       /*  SENSE KEY!  */

                if (d->filemark) {
                        xferp->data_in[2] = 0x80;
                }
                debug(": [2]=0x%02x ", xferp->data_in[2]);

                printf(" XXX(!) \n");

                /*  TODO  */
                xferp->data_in[7] = retlen - 7; /*  additional sense length  */
                /*  TODO  */

                diskimage__return_default_status_and_message(xferp);
                break;

        case SCSICMD_READ_BLOCK_LIMITS:
                debug("READ_BLOCK_LIMITS");

                retlen = 6;

                /*  TODO: bits 765 of buf[1] contains the LUN  */
                if (xferp->cmd[1] != 0x00)
                        fatal("WARNING: READ_BLOCK_LIMITS with cmd[1]="
                            "0x%02x not yet implemented\n", (int)xferp->cmd[1]);

                /*  Return data:  */
                scsi_transfer_allocbuf(&xferp->data_in_len, &xferp->data_in,
                    retlen, 1);

                /*
                 *  data[0] is reserved, data[1..3] contain the maximum block
                 *  length limit, data[4..5] contain the minimum limit.
                 */

                {
                        int max_limit = 32768;
                        int min_limit = 128;

                        xferp->data_in[1] = (max_limit >> 16) & 255;
                        xferp->data_in[2] = (max_limit >>  8) & 255;
                        xferp->data_in[3] =  max_limit        & 255;
                        xferp->data_in[4] = (min_limit >>  8) & 255;
                        xferp->data_in[5] =  min_limit        & 255;
                }

                diskimage__return_default_status_and_message(xferp);
                break;

        case SCSICMD_REWIND:
                debug("REWIND");

                /*  TODO: bits 765 of buf[1] contains the LUN  */
                if ((xferp->cmd[1] & 0xe0) != 0x00)
                        fatal("WARNING: REWIND with cmd[1]=0x%02x not yet "
                            "implemented\n", (int)xferp->cmd[1]);

                /*  Close and reopen.  */

                if (d->f != NULL)
                        fclose(d->f);

                d->f = fopen(d->fname, d->writable? "r+" : "r");
                if (d->f == NULL) {
                        fprintf(stderr, "[ diskimage: could not (re)open "
                            "'%s' ]\n", d->fname);
                        /*  TODO: return error  */
                }

                d->tape_offset = 0;
                d->tape_filenr = 0;
                d->filemark = 0;

                diskimage__return_default_status_and_message(xferp);
                break;

        case SCSICMD_SPACE:
                debug("SPACE");

                /*  TODO: bits 765 of buf[1] contains the LUN  */
                if ((xferp->cmd[1] & 0xe0) != 0x00)
                        fatal("WARNING: SPACE with cmd[1]=0x%02x not yet "
                            "implemented\n", (int)xferp->cmd[1]);

                /*
                 *  Bits 2..0 of buf[1] contain the 'code' which describes how
                 *  spacing should be done, and buf[2..4] contain the number of
                 *  operations.
                 */
                debug("[ SPACE: buf[] = %02x %02x %02x %02x %02x %02x ]\n",
                    xferp->cmd[0],
                    xferp->cmd[1],
                    xferp->cmd[2],
                    xferp->cmd[3],
                    xferp->cmd[4],
                    xferp->cmd[5]);

                switch (xferp->cmd[1] & 7) {
                case 1: /*  Seek to a different file nr:  */
                        {
                                int diff = (xferp->cmd[2] << 16) +
                                    (xferp->cmd[3] << 8) + xferp->cmd[4];

                                /*  Negative seek offset:  */
                                if (diff & (1 << 23))
                                        diff = - (16777216 - diff);

                                d->tape_filenr += diff;
                        }

                        /*  At end of file, switch to the next tape file:  */
                        if (d->filemark) {
                                d->tape_filenr ++;
                                d->filemark = 0;
                        }

                        debug("{ switching to tape file %i }", d->tape_filenr);
                        diskimage__switch_tape(d);
                        d->filemark = 0;
                        break;
                default:
                        fatal("[ diskimage.c: unimplemented SPACE type %i ]\n",
                            xferp->cmd[1] & 7);
                }

                diskimage__return_default_status_and_message(xferp);
                break;

        case SCSICDROM_READ_SUBCHANNEL:
                /*
                 *  According to
                 *  http://mail-index.netbsd.org/port-i386/1997/03/03/0010.html:
                 *
                 *  "The READ_CD_CAPACITY, READ_SUBCHANNEL, and MODE_SELECT
                 *   commands have the same opcode in SCSI or ATAPI, but don't
                 *   have the same command structure"...
                 *
                 *  TODO: This still doesn't work. Hm.
                 */
                retlen = 48;

                debug("CDROM_READ_SUBCHANNEL/READ_CD_CAPACITY, cmd[1]=0x%02x",
                    xferp->cmd[1]);

                /*  Return data:  */
                scsi_transfer_allocbuf(&xferp->data_in_len,
                    &xferp->data_in, retlen, 1);

                diskimage_recalc_size(d);

                size = d->total_size / d->logical_block_size;
                if (d->total_size & (d->logical_block_size-1))
                        size ++;

                xferp->data_in[0] = (size >> 24) & 255;
                xferp->data_in[1] = (size >> 16) & 255;
                xferp->data_in[2] = (size >> 8) & 255;
                xferp->data_in[3] = size & 255;

                xferp->data_in[4] = (d->logical_block_size >> 24) & 255;
                xferp->data_in[5] = (d->logical_block_size >> 16) & 255;
                xferp->data_in[6] = (d->logical_block_size >> 8) & 255;
                xferp->data_in[7] = d->logical_block_size & 255;

                diskimage__return_default_status_and_message(xferp);
                break;

        case SCSICDROM_READ_TOC:
                debug("(CDROM_READ_TOC: ");
                debug("lun=%i msf=%i ",
                    xferp->cmd[1] >> 5, (xferp->cmd[1] >> 1) & 1);
                debug("starting_track=%i ", xferp->cmd[6]);
                retlen = xferp->cmd[7] * 256 + xferp->cmd[8];
                debug("allocation_len=%i)\n", retlen);

                /*  Return data:  */
                scsi_transfer_allocbuf(&xferp->data_in_len,
                    &xferp->data_in, retlen, 1);

                xferp->data_in[0] = 0;
                xferp->data_in[1] = 10;
                xferp->data_in[2] = 0;          /*  First track.  */
                xferp->data_in[3] = 0;          /*  Last track.  */

                /*  Track 0 data:  */
                xferp->data_in[4] = 0x00;       /*  Reserved.  */
                xferp->data_in[5] = 0x04;       /*  ADR + CTRL:
                                                    Data, not audio  */
                xferp->data_in[6] = 0x00;       /*  Track nr  */
                xferp->data_in[7] = 0x00;       /*  Reserved  */
                /*  8..11 = absolute CDROM address  */

                diskimage__return_default_status_and_message(xferp);
                break;

        case SCSICDROM_READ_DISCINFO:
                /*  (Patch from Håvard Eidnes.)  */
                debug("CDROM_READ_DISCINFO, cmd[1]=0x%02x", xferp->cmd[1]);
                retlen = 34;
                scsi_transfer_allocbuf(&xferp->data_in_len,
                    &xferp->data_in, retlen, 1);

                /*  TODO: Make this more generic!  */
                xferp->data_in[0] = retlen-2;   /*  length of info, excl len  */
                xferp->data_in[1] = 0;   /*  length of info-(len field), msb  */
                xferp->data_in[2] = 0xE; /*  11=complete ses., 10=fin disc  */
                xferp->data_in[3] = 0;   /*  First track on disc  */
                xferp->data_in[4] = 1;   /*  Number of sessions, lsb  */
                xferp->data_in[5] = 0;   /*  first_track_last_session_lsb  */
                xferp->data_in[6] = 0;   /*  last_track_last_session_lsb  */
                xferp->data_in[7] = 0x20;/*  various flags  */
                xferp->data_in[8] = 0;   /*  CD-ROM disc  */
                xferp->data_in[9] = 1;   /*  num sessions, msb  */
                xferp->data_in[10] = 0;  /*  first_track_last_session_msb  */
                xferp->data_in[11] = 0;  /*  last_track_last_session_msb  */
                {
                        int i;
                        /*  Lead-in data, for completed cd-rom:  */
                        for (i=16; i<=23; i++)
                                xferp->data_in[i] = 0xff;
                }

                diskimage__return_default_status_and_message(xferp);
                break;

        case SCSICDROM_READ_TRACKINFO:
                /*  (Patch from Håvard Eidnes.)  */
                debug("CDROM_READ_TRACKINFO");
                retlen = 36;
                scsi_transfer_allocbuf(&xferp->data_in_len,
                    &xferp->data_in, retlen, 1);

                diskimage_recalc_size(d);

                size = d->total_size / d->logical_block_size;
                if (d->total_size & (d->logical_block_size-1))
                        size ++;

                /*  TODO: Make more generic?  */
                /*  TODO: Don't use magic values.  */
                xferp->data_in[0] = retlen-2; /*  length of info, excl len  */
                xferp->data_in[1] = 0;        /*  length of info, msb  */
                xferp->data_in[2] = 1;        /*  track#, lsb  */
                xferp->data_in[3] = 1;        /*  session#, lsb  */
                xferp->data_in[4] = 0;        /*  reserved  */
                xferp->data_in[5] = 0x6;      /*  trk mode: unintr. data,
                                                  copyable  */
                xferp->data_in[6] = 0x81;     /*  trk info: RT + trk mode  */
                xferp->data_in[7] = 0x2;      /*  last rec=valid, next w=not
                                                  valid */
                {
                        /*
                         *  track start, next writable, free blcks,
                         *  blocking factor
                         */
                        int i;
                        for(i=8; i<=23; i++)
                                xferp->data_in[i] = 0;
                }

                /*  Track size:  */
                xferp->data_in[24] = (size >> 24) & 0xff;
                xferp->data_in[25] = (size >> 16) & 0xff;
                xferp->data_in[26] = (size >> 8) & 0xff;
                xferp->data_in[27] = size & 0xff;

                /*  Last recorded address, only for dvd; zero out the rest:  */
                {
                        int i;
                        for (i=28; i<=35; i++)
                                xferp->data_in[i] = 0;
                }

                diskimage__return_default_status_and_message(xferp);
                break;

        case SCSICMD_MODE_SELECT:
                debug("[ SCSI MODE_SELECT: ");

                /*
                 *  TODO:
                 *
                 *  This is super-hardcoded for NetBSD's usage of mode_select
                 *  to set the size of CDROM sectors to 2048.
                 */

                if (xferp->data_out_offset == 0) {
                        xferp->data_out_len = 12;       /*  TODO  */
                        debug("data_out == NULL, wanting %i bytes ]\n",
                            (int)xferp->data_out_len);
                        return 2;
                }

                debug("data_out!=NULL (OK), ");

                /*  TODO:  Care about cmd?  */

                /*  Set sector size to 2048:  */
                /*  00 05 00 08 00 03 ca 40 00 00 08 00  */
                if (xferp->data_out[0] == 0x00 &&
                    xferp->data_out[1] == 0x05 &&
                    xferp->data_out[2] == 0x00 &&
                    xferp->data_out[3] == 0x08) {
                        d->logical_block_size =
                            (xferp->data_out[9] << 16) +
                            (xferp->data_out[10] << 8) +
                            xferp->data_out[11];
                        debug("[ setting logical_block_size to %i ]\n",
                            d->logical_block_size);
                } else {
                        int i;
                        fatal("[ unknown MODE_SELECT: cmd =");
                        for (i=0; i<(ssize_t)xferp->cmd_len; i++)
                                fatal(" %02x", xferp->cmd[i]);
                        fatal(", data_out =");
                        for (i=0; i<(ssize_t)xferp->data_out_len; i++)
                                fatal(" %02x", xferp->data_out[i]);
                        fatal(" ]");
                }

                debug(" ]\n");
                diskimage__return_default_status_and_message(xferp);
                break;

        case SCSICMD_PREVENT_ALLOW_REMOVE:
                debug("[ SCSI 0x%02x Prevent/allow medium removal: "
                    "TODO ]\n", xferp->cmd[0]);

                diskimage__return_default_status_and_message(xferp);
                break;

        case 0xbd:
                fatal("[ SCSI 0x%02x (len %i), TODO: ", xferp->cmd[0],
                    xferp->cmd_len);
                for (i=0; i<(ssize_t)xferp->cmd_len; i++)
                        fatal(" %02x", xferp->cmd[i]);
                fatal(" ]\n");

                /*
                 *  Used by Windows NT?
                 *
                 *  Not documented in http://www.danbbs.dk/~dino/
                 *              SCSI/SCSI2-D.html.
                 *  Google gave the answer "MECHANISM_STATUS" for ATAPI. Hm.
                 */

                if (xferp->cmd_len < 12) {
                        fatal("WEIRD LEN?\n");
                        retlen = 8;
                } else {
                        retlen = xferp->cmd[8] * 256 + xferp->cmd[9];
                }

                /*  Return data:  */
                scsi_transfer_allocbuf(&xferp->data_in_len,
                    &xferp->data_in, retlen, 1);

                diskimage__return_default_status_and_message(xferp);

                break;

        default:
                fatal("[ UNIMPLEMENTED SCSI command 0x%02x, disk id=%i ]\n",
                    xferp->cmd[0], id);
                exit(1);
        }
        debug(" ]\n");

        return 1;
}

