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#include <u.h>
#include <libc.h>
/*
 * BUGS:
 *      no luns
 *      and incomplete in many other ways
 */
#include <disk.h>
#include "scsireq.h"

enum {
        Debug = 0,
};

/*
 * exabyte tape drives, at least old ones like the 8200 and 8505,
 * are dumb: you have to read the exact block size on the tape,
 * they don't take 10-byte SCSI commands, and various other fine points.
 */
extern int exabyte, force6bytecmds;

static int debug = Debug;

long
SRready(ScsiReq *rp)
{
        uchar cmd[6];

        memset(cmd, 0, sizeof cmd);
        rp->cmd.p = cmd;
        rp->cmd.count = sizeof cmd;
        rp->data.p = cmd;
        rp->data.count = 0;
        rp->data.write = 1;
        return SRrequest(rp);
}

long
SRrewind(ScsiReq *rp)
{
        uchar cmd[6];

        memset(cmd, 0, sizeof cmd);
        cmd[0] = ScmdRewind;
        rp->cmd.p = cmd;
        rp->cmd.count = sizeof cmd;
        rp->data.p = cmd;
        rp->data.count = 0;
        rp->data.write = 1;
        if(SRrequest(rp) >= 0){
                rp->offset = 0;
                return 0;
        }
        return -1;
}

long
SRreqsense(ScsiReq *rp)
{
        uchar cmd[6];
        ScsiReq req;
        long status;

        if(rp->status == Status_SD){
                rp->status = STok;
                return 0;
        }
        memset(cmd, 0, sizeof cmd);
        cmd[0] = ScmdRsense;
        cmd[4] = sizeof(req.sense);
        memset(&req, 0, sizeof(req));
        if(rp->flags&Fusb)
                req.flags |= Fusb;
        req.fd = rp->fd;
        req.umsc = rp->umsc;
        req.cmd.p = cmd;
        req.cmd.count = sizeof cmd;
        req.data.p = rp->sense;
        req.data.count = sizeof(rp->sense);
        req.data.write = 0;
        status = SRrequest(&req);
        rp->status = req.status;
        return status;
}

long
SRformat(ScsiReq *rp)
{
        uchar cmd[6];

        memset(cmd, 0, sizeof cmd);
        cmd[0] = ScmdFormat;
        rp->cmd.p = cmd;
        rp->cmd.count = sizeof cmd;
        rp->data.p = cmd;
        rp->data.count = 6;
        rp->data.write = 0;
        return SRrequest(rp);
}

long
SRrblimits(ScsiReq *rp, uchar *list)
{
        uchar cmd[6];

        memset(cmd, 0, sizeof cmd);
        cmd[0] = ScmdRblimits;
        rp->cmd.p = cmd;
        rp->cmd.count = sizeof cmd;
        rp->data.p = list;
        rp->data.count = 6;
        rp->data.write = 0;
        return SRrequest(rp);
}

static int
dirdevrw(ScsiReq *rp, uchar *cmd, long nbytes)
{
        long n;

        n = nbytes / rp->lbsize;
        if(rp->offset <= Max24off && n <= 256 && (rp->flags & Frw10) == 0){
                PUTBE24(cmd+1, rp->offset);
                cmd[4] = n;
                cmd[5] = 0;
                return 6;
        }
        cmd[0] |= ScmdExtread;
        cmd[1] = 0;
        PUTBELONG(cmd+2, rp->offset);
        cmd[6] = 0;
        cmd[7] = n>>8;
        cmd[8] = n;
        cmd[9] = 0;
        return 10;
}

static int
seqdevrw(ScsiReq *rp, uchar *cmd, long nbytes)
{
        long n;

        /* don't set Cmd1sili; we want the ILI bit instead of a fatal error */
        cmd[1] = rp->flags&Fbfixed? Cmd1fixed: 0;
        n = nbytes / rp->lbsize;
        PUTBE24(cmd+2, n);
        cmd[5] = 0;
        return 6;
}

long
SRread(ScsiReq *rp, void *buf, long nbytes)
{
        uchar cmd[10];
        long n;

        if((nbytes % rp->lbsize) || nbytes > maxiosize){
                if(debug)
                        if (nbytes % rp->lbsize)
                                fprint(2, "scuzz: i/o size %ld %% %ld != 0\n",
                                        nbytes, rp->lbsize);
                        else
                                fprint(2, "scuzz: i/o size %ld > %ld\n",
                                        nbytes, maxiosize);
                rp->status = Status_BADARG;
                return -1;
        }

        /* set up scsi read cmd */
        cmd[0] = ScmdRead;
        if(rp->flags & Fseqdev)
                rp->cmd.count = seqdevrw(rp, cmd, nbytes);
        else
                rp->cmd.count = dirdevrw(rp, cmd, nbytes);
        rp->cmd.p = cmd;
        rp->data.p = buf;
        rp->data.count = nbytes;
        rp->data.write = 0;

        /* issue it */
        n = SRrequest(rp);
        if(n != -1){                    /* it worked? */
                rp->offset += n / rp->lbsize;
                return n;
        }

        /* request failed; maybe we just read a short record? */
        if (exabyte) {
                fprint(2, "read error\n");
                rp->status = STcheck;
                return n;
        }
        if(rp->status != Status_SD || !(rp->sense[0] & Sd0valid))
                return -1;
        /* compute # of bytes not read */
        n = GETBELONG(rp->sense+3) * rp->lbsize;
        if (debug)
                fprint(2,
        "SRread: request failed with sense data; sense byte count %ld\n",
                        n);
        if(!(rp->flags & Fseqdev))
                return -1;

        /* device is a tape or something similar */
        if (rp->sense[2] == Sd2filemark || rp->sense[2] == 0x08 ||
            rp->sense[2] & Sd2ili && n > 0)
                rp->data.count = nbytes - n;
        else
                return -1;
        n = rp->data.count;
        if (!rp->readblock++ || debug)
                fprint(2, "SRread: tape data count %ld%s\n", n,
                        (rp->sense[2] & Sd2ili? " with ILI": ""));
        rp->status = STok;
        rp->offset += n / rp->lbsize;
        return n;
}

long
SRwrite(ScsiReq *rp, void *buf, long nbytes)
{
        uchar cmd[10];
        long n;

        if((nbytes % rp->lbsize) || nbytes > maxiosize){
                if(debug)
                        if (nbytes % rp->lbsize)
                                fprint(2, "scuzz: i/o size %ld %% %ld != 0\n",
                                        nbytes, rp->lbsize);
                        else
                                fprint(2, "scuzz: i/o size %ld > %ld\n",
                                        nbytes, maxiosize);
                rp->status = Status_BADARG;
                return -1;
        }

        /* set up scsi write cmd */
        cmd[0] = ScmdWrite;
        if(rp->flags & Fseqdev)
                rp->cmd.count = seqdevrw(rp, cmd, nbytes);
        else
                rp->cmd.count = dirdevrw(rp, cmd, nbytes);
        rp->cmd.p = cmd;
        rp->data.p = buf;
        rp->data.count = nbytes;
        rp->data.write = 1;

        /* issue it */
        if((n = SRrequest(rp)) == -1){
                if (exabyte) {
                        fprint(2, "write error\n");
                        rp->status = STcheck;
                        return n;
                }
                if(rp->status != Status_SD || rp->sense[2] != Sd2eom)
                        return -1;
                if(rp->sense[0] & Sd0valid){
                        n -= GETBELONG(rp->sense+3) * rp->lbsize;
                        rp->data.count = nbytes - n;
                }
                else
                        rp->data.count = nbytes;
                n = rp->data.count;
        }
        rp->offset += n / rp->lbsize;
        return n;
}

long
SRseek(ScsiReq *rp, long offset, int type)
{
        uchar cmd[10];

        switch(type){

        case 0:
                break;

        case 1:
                offset += rp->offset;
                if(offset >= 0)
                        break;
                /*FALLTHROUGH*/

        default:
                if(debug)
                        fprint(2, "scuzz: seek failed\n");
                rp->status = Status_BADARG;
                return -1;
        }
        memset(cmd, 0, sizeof cmd);
        if(offset <= Max24off && (rp->flags & Frw10) == 0){
                cmd[0] = ScmdSeek;
                PUTBE24(cmd+1, offset & Max24off);
                rp->cmd.count = 6;
        }else{
                cmd[0] = ScmdExtseek;
                PUTBELONG(cmd+2, offset);
                rp->cmd.count = 10;
        }
        rp->cmd.p = cmd;
        rp->data.p = cmd;
        rp->data.count = 0;
        rp->data.write = 1;
        SRrequest(rp);
        if(rp->status == STok)
                return rp->offset = offset;
        return -1;
}

long
SRfilemark(ScsiReq *rp, ulong howmany)
{
        uchar cmd[6];

        memset(cmd, 0, sizeof cmd);
        cmd[0] = ScmdFmark;
        PUTBE24(cmd+2, howmany);
        rp->cmd.p = cmd;
        rp->cmd.count = sizeof cmd;
        rp->data.p = cmd;
        rp->data.count = 0;
        rp->data.write = 1;
        return SRrequest(rp);
}

long
SRspace(ScsiReq *rp, uchar code, long howmany)
{
        uchar cmd[6];

        memset(cmd, 0, sizeof cmd);
        cmd[0] = ScmdSpace;
        cmd[1] = code;
        PUTBE24(cmd+2, howmany);
        rp->cmd.p = cmd;
        rp->cmd.count = sizeof cmd;
        rp->data.p = cmd;
        rp->data.count = 0;
        rp->data.write = 1;
        /*
         * what about rp->offset?
         */
        return SRrequest(rp);
}

long
SRinquiry(ScsiReq *rp)
{
        uchar cmd[6];

        memset(cmd, 0, sizeof cmd);
        cmd[0] = ScmdInq;
        cmd[4] = sizeof rp->inquiry;
        rp->cmd.p = cmd;
        rp->cmd.count = sizeof cmd;
        memset(rp->inquiry, 0, sizeof rp->inquiry);
        rp->data.p = rp->inquiry;
        rp->data.count = sizeof rp->inquiry;
        rp->data.write = 0;
        if(SRrequest(rp) >= 0){
                rp->flags |= Finqok;
                return 0;
        }
        rp->flags &= ~Finqok;
        return -1;
}

long
SRmodeselect6(ScsiReq *rp, uchar *list, long nbytes)
{
        uchar cmd[6];

        memset(cmd, 0, sizeof cmd);
        cmd[0] = ScmdMselect6;
        if((rp->flags & Finqok) && (rp->inquiry[2] & 0x07) >= 2)
                cmd[1] = 0x10;
        cmd[4] = nbytes;
        rp->cmd.p = cmd;
        rp->cmd.count = sizeof cmd;
        rp->data.p = list;
        rp->data.count = nbytes;
        rp->data.write = 1;
        return SRrequest(rp);
}

long
SRmodeselect10(ScsiReq *rp, uchar *list, long nbytes)
{
        uchar cmd[10];

        memset(cmd, 0, sizeof cmd);
        if((rp->flags & Finqok) && (rp->inquiry[2] & 0x07) >= 2)
                cmd[1] = 0x10;
        cmd[0] = ScmdMselect10;
        cmd[7] = nbytes>>8;
        cmd[8] = nbytes;
        rp->cmd.p = cmd;
        rp->cmd.count = sizeof cmd;
        rp->data.p = list;
        rp->data.count = nbytes;
        rp->data.write = 1;
        return SRrequest(rp);
}

long
SRmodesense6(ScsiReq *rp, uchar page, uchar *list, long nbytes)
{
        uchar cmd[6];

        memset(cmd, 0, sizeof cmd);
        cmd[0] = ScmdMsense6;
        cmd[2] = page;
        cmd[4] = nbytes;
        rp->cmd.p = cmd;
        rp->cmd.count = sizeof cmd;
        rp->data.p = list;
        rp->data.count = nbytes;
        rp->data.write = 0;
        return SRrequest(rp);
}

long
SRmodesense10(ScsiReq *rp, uchar page, uchar *list, long nbytes)
{
        uchar cmd[10];

        memset(cmd, 0, sizeof cmd);
        cmd[0] = ScmdMsense10;
        cmd[2] = page;
        cmd[7] = nbytes>>8;
        cmd[8] = nbytes;
        rp->cmd.p = cmd;
        rp->cmd.count = sizeof cmd;
        rp->data.p = list;
        rp->data.count = nbytes;
        rp->data.write = 0;
        return SRrequest(rp);
}

long
SRstart(ScsiReq *rp, uchar code)
{
        uchar cmd[6];

        memset(cmd, 0, sizeof cmd);
        cmd[0] = ScmdStart;
        cmd[4] = code;
        rp->cmd.p = cmd;
        rp->cmd.count = sizeof cmd;
        rp->data.p = cmd;
        rp->data.count = 0;
        rp->data.write = 1;
        return SRrequest(rp);
}

long
SRrcapacity(ScsiReq *rp, uchar *data)
{
        uchar cmd[10];

        memset(cmd, 0, sizeof cmd);
        cmd[0] = ScmdRcapacity;
        rp->cmd.p = cmd;
        rp->cmd.count = sizeof cmd;
        rp->data.p = data;
        rp->data.count = 8;
        rp->data.write = 0;
        return SRrequest(rp);
}

static long
request(int fd, ScsiPtr *cmd, ScsiPtr *data, int *status)
{
        long n, r;
        char buf[16];

        /* this was an experiment but it seems to be a good idea */
        *status = STok;

        /* send SCSI command */
        if(write(fd, cmd->p, cmd->count) != cmd->count){
                fprint(2, "scsireq: write cmd: %r\n");
                *status = Status_SW;
                return -1;
        }

        /* read or write actual data */
        werrstr("");
        if(data->write)
                n = write(fd, data->p, data->count);
        else {
                n = read(fd, data->p, data->count);
                if (n < 0)
                        memset(data->p, 0, data->count);
                else if (n < data->count)
                        memset(data->p + n, 0, data->count - n);
        }
        if (n != data->count && n <= 0) {
                if (debug)
                        fprint(2,
        "request: tried to %s %ld bytes of data for cmd 0x%x but got %r\n",
                                (data->write? "write": "read"),
                                data->count, cmd->p[0]);
        } else if (n != data->count && (data->write || debug))
                fprint(2, "request: %s %ld of %ld bytes of actual data\n",
                        (data->write? "wrote": "read"), n, data->count);

        /* read status */
        buf[0] = '\0';
        r = read(fd, buf, sizeof buf-1);
        if(exabyte && r <= 0 || !exabyte && r < 0){
                fprint(2, "scsireq: read status: %r\n");
                *status = Status_SW;
                return -1;
        }
        if (r >= 0)
                buf[r] = '\0';
        *status = atoi(buf);
        if(n < 0 && (exabyte || *status != STcheck))
                fprint(2, "scsireq: status 0x%2.2uX: data transfer: %r\n",
                        *status);
        return n;
}

long
SRrequest(ScsiReq *rp)
{
        long n;
        int status;

retry:
        if(rp->flags&Fusb)
                n = umsrequest(rp->umsc, &rp->cmd, &rp->data, &status);
        else
                n = request(rp->fd, &rp->cmd, &rp->data, &status);
        switch(rp->status = status){

        case STok:
                rp->data.count = n;
                break;

        case STcheck:
                if(rp->cmd.p[0] != ScmdRsense && SRreqsense(rp) != -1)
                        rp->status = Status_SD;
                if (exabyte)
                        fprint(2, "SRrequest: STcheck, returning -1\n");
                return -1;

        case STbusy:
                sleep(1000);
                goto retry;

        default:
                fprint(2, "status 0x%2.2uX\n", status);
                return -1;
        }
        return n;
}

int
SRclose(ScsiReq *rp)
{
        if((rp->flags & Fopen) == 0){
                if(debug)
                        fprint(2, "scuzz: closing closed file\n");
                rp->status = Status_BADARG;
                return -1;
        }
        close(rp->fd);
        rp->flags = 0;
        return 0;
}

uint
mkascq(ScsiReq *r)
{
        uchar *u;

        u = r->sense;
        return u[2]<<16 | u[12]<<8 | u[13];
}

static int
dirdevopen(ScsiReq *rp)
{
        ulong blocks;
        uchar data[8];

        if(SRstart(rp, 1) == -1)
                /*
                 * it's okay for removable media to say
                 * "check condition: medium not present".
                 * 3a is "medium not present".
                 */
                return rp->inquiry[1] & 0x80 && (mkascq(rp) >> 8) == 0x023a?
                        0: -1;
        memset(data, 0, sizeof data);
        if(SRrcapacity(rp, data) == -1)
                return -1;
        rp->lbsize = GETBELONG(data+4);
        blocks =     GETBELONG(data);
        if(debug)
                fprint(2, "scuzz: dirdevopen: logical block size %lud, "
                        "# blocks %lud\n", rp->lbsize, blocks);
        /* some newer dev's don't support 6-byte commands */
        if(blocks > Max24off && !force6bytecmds)
                rp->flags |= Frw10;
        return 0;
}

static int
seqdevopen(ScsiReq *rp)
{
        uchar mode[16], limits[6];

        if(SRrblimits(rp, limits) == -1)
                return -1;
        if(limits[1] == 0 && limits[2] == limits[4] && limits[3] == limits[5]){
                rp->flags |= Fbfixed;
                rp->lbsize = limits[4]<<8 | limits[5];
                if(debug)
                        fprint(2, "scuzz: seqdevopen: logical block size %lud\n",
                                rp->lbsize);
                return 0;
        }
        /*
         * On some older hardware the optional 10-byte
         * modeselect command isn't implemented.
         */
        if (force6bytecmds)
                rp->flags |= Fmode6;
        if(!(rp->flags & Fmode6)){
                /* try 10-byte command first */
                memset(mode, 0, sizeof mode);
                mode[3] = 0x10;         /* device-specific param. */
                mode[7] = 8;            /* block descriptor length */
                /*
                 * exabytes can't handle this, and
                 * modeselect(10) is optional.
                 */
                if(SRmodeselect10(rp, mode, sizeof mode) != -1){
                        rp->lbsize = 1;
                        return 0;       /* success */
                }
                /* can't do 10-byte commands, back off to 6-byte ones */
                rp->flags |= Fmode6;
        }

        /* 6-byte command */
        memset(mode, 0, sizeof mode);
        mode[2] = 0x10;         /* device-specific param. */
        mode[3] = 8;            /* block descriptor length */
        /*
         * bsd sez exabytes need this bit (NBE: no busy enable) in
         * vendor-specific page (0), but so far we haven't needed it.
        mode[12] |= 8;
         */
        if(SRmodeselect6(rp, mode, 4+8) == -1)
                return -1;
        rp->lbsize = 1;
        return 0;
}

static int
wormdevopen(ScsiReq *rp)
{
        long status;
        uchar list[MaxDirData];

        if (SRstart(rp, 1) == -1 ||
            (status = SRmodesense10(rp, Allmodepages, list, sizeof list)) == -1)
                return -1;
        /* nbytes = list[0]<<8 | list[1]; */

        /* # of bytes of block descriptors of 8 bytes each; not even 1? */
        if((list[6]<<8 | list[7]) < 8)
                rp->lbsize = 2048;
        else
                /* last 3 bytes of block 0 descriptor */
                rp->lbsize = GETBE24(list+13);
        if(debug)
                fprint(2, "scuzz: wormdevopen: logical block size %lud\n",
                        rp->lbsize);
        return status;
}

int
SRopenraw(ScsiReq *rp, char *unit)
{
        char name[128];

        if(rp->flags & Fopen){
                if(debug)
                        fprint(2, "scuzz: opening open file\n");
                rp->status = Status_BADARG;
                return -1;
        }
        memset(rp, 0, sizeof *rp);
        rp->unit = unit;

        sprint(name, "%s/raw", unit);

        if((rp->fd = open(name, ORDWR)) == -1){
                rp->status = STtimeout;
                return -1;
        }
        rp->flags = Fopen;
        return 0;
}

int
SRopen(ScsiReq *rp, char *unit)
{
        if(SRopenraw(rp, unit) == -1)
                return -1;
        SRready(rp);
        if(SRinquiry(rp) >= 0){
                switch(rp->inquiry[0]){

                default:
                        fprint(2, "unknown device type 0x%.2x\n", rp->inquiry[0]);
                        rp->status = Status_SW;
                        break;

                case 0x00:      /* Direct access (disk) */
                case 0x05:      /* CD-ROM */
                case 0x07:      /* rewriteable MO */
                        if(dirdevopen(rp) == -1)
                                break;
                        return 0;

                case 0x01:      /* Sequential eg: tape */
                        rp->flags |= Fseqdev;
                        if(seqdevopen(rp) == -1)
                                break;
                        return 0;

                case 0x02:      /* Printer */
                        rp->flags |= Fprintdev;
                        return 0;

                case 0x04:      /* Worm */
                        rp->flags |= Fwormdev;
                        if(wormdevopen(rp) == -1)
                                break;
                        return 0;

                case 0x08:      /* medium-changer */
                        rp->flags |= Fchanger;
                        return 0;
                }
        }
        SRclose(rp);
        return -1;
}