xmodem.c

完整的Bell实验室的嵌入式文件系统TFS

{
    int     i;
    char    *pkt;
    uchar   seq[2];

    getbytes(seq,2,1);
    Mtrace("*");
    if (xip->flags & VERIFY) {
        getbytes(tmppkt,xip->pktlen,1);
        for(i=0;i<xip->pktlen;i++) {
            if (tmppkt[i] != ((char *)xip->dataddr)[i]) {
                if (xip->errcnt++ == 0)
                    xip->firsterrat = (char *)(xip->dataddr+i);
            }
        }
        pkt = (char *)tmppkt;
    }
    else {
        getbytes((char *)xip->dataddr,xip->pktlen,1);
        pkt = (char *)xip->dataddr;
    }

    Mtrace("*");

    if (xip->flags & USECRC) {
        ushort  crc, xcrc;
        
        /* An "endian independent way to combine the CRC bytes. */
        crc  = (ushort)getchar() << 8;
        crc += (ushort)getchar();
        xcrc = xcrc16((uchar *)pkt,(ulong)(xip->pktlen));
        if (crc != xcrc) {
            rputchar(CAN);
            Mtrace("1 %04x != %04x",crc,xcrc);
            return(-1);
        }
    }
    else {
        uchar   csum, xcsum;

        xcsum = (uchar)getchar();
        Mtrace("*");
        csum = 0;
        for(i=0;i<xip->pktlen;i++)
            csum += *pkt++;
        if (csum != xcsum) {
            rputchar(CAN);
            Mtrace("2");
            Mtrace("2 %02x != %02x",csum,xcsum);
            return(-1);
        }
    }
    if ((uchar)seq[0] !=  xip->sno) {
        if ((xip->sno == 0x02) && (seq[0] == 0x01)) {   /* TeraTerm has a */
            xip->sno = 0x01;                            /* "peculiarity". */
            Mtrace("--TERABUG--");
        }
        else {
            rputchar(CAN);
            Mtrace("3 %02x != %02x",seq[0],xip->sno);
            return(-1);
        }
    }
    if ((uchar)seq[1] != (uchar)~(xip->sno)) {
        rputchar(CAN);
        Mtrace("4 %02x != %02x",seq[1],(uchar)~(xip->sno));
        return(-1);
    }
    /* First packet of YMODEM contains information about the transfer: */
    /* FILENAME SP FILESIZE SP MOD_DATE SP FILEMODE SP FILE_SNO */
    /* Only the FILENAME is required and if others are present, then none */
    /* can be skipped. */
    if ((xip->flags & YMODEM) && (xip->pktcnt == 0)) {
        char *slash, *space, *fname;

        slash = strrchr((char *)(xip->dataddr),'/');
        space = strchr((char *)(xip->dataddr),' ');
        if (slash)
            fname = slash+1;
        else
            fname = (char *)(xip->dataddr);
        Mtrace("<fname=%s>",fname);
        if (space) {
            *space = 0;
            xip->size = atoi(space+1);
        }
        strcpy(xip->fname,fname);
        if (fname[0])
            xip->filcnt++;
    }
    else
        xip->dataddr += xip->pktlen;
    xip->sno++;
    xip->pktcnt++;
    xip->xfertot += xip->pktlen;
    rputchar(ACK);
    if (xip->flags & YMODEM) {
        if (xip->fname[0] == 0) {
            printf("\nRcvd %d file%c\n",
                xip->filcnt,xip->filcnt > 1 ? 's' : ' ');
            return(1);
        }
    }
    return(0);
}

/* Xup():
 * Called when a transfer from target to host is being made (considered
 * an upload).
 */
static int
Xup(struct xinfo *xip)
{
    uchar   c, buf[PKTLEN_128];
    int     done, pktlen;
    long    actualsize;

    Mtrace("Xup starting");

    actualsize = xip->size;

    if (xip->size & 0x7f) {
        xip->size += 128;
        xip->size &= 0xffffff80L;
    }

    printf("Upload %ld bytes from 0x%lx\n",xip->size,(ulong)xip->base);

    /* Startup synchronization... */
    /* Wait to receive a NAK or 'C' from receiver. */
    done = 0;
    while(!done) {
        c = (uchar)getchar();
        switch(c) {
        case NAK:
            done = 1;
            Mtrace("CSM");
            break;
        case 'C':
            xip->flags |= USECRC;
            done = 1;
            Mtrace("CRC");
            break;
        case 'q':   /* ELS addition, not part of XMODEM spec. */
            return(0);
        default:
            break;
        }
    }


    if (xip->flags & YMODEM) {
        Mtrace("SNO_0");
        xip->sno = 0;
        xip->pktcnt = -1;
        memset((char *)buf,0,PKTLEN_128);
        sprintf(buf,"%s",xip->fname);
        pktlen = xip->pktlen;
        xip->pktlen = PKTLEN_128;
        putPacket(buf,xip);
        xip->pktlen = pktlen;
    }

    done = 0;
    xip->sno = 1;
    xip->pktcnt = 0;
    while(!done) {
        c = (uchar)putPacket((uchar *)(xip->dataddr),xip);
        switch(c) {
        case ACK:
            xip->sno++;
            xip->pktcnt++;
            xip->size -= xip->pktlen;
            xip->dataddr += xip->pktlen;
            Mtrace("A");
            break;
        case NAK:
            Mtrace("N");
            break;
        case CAN:
            done = -1;
            Mtrace("C");
            break;
        case EOT:
            done = -1;
            Mtrace("E");
            break;
        default:
            done = -1;
            Mtrace("<%2x>",c);
            break;
        }
        if (xip->size <= 0) {
            rputchar(EOT);
            getchar();  /* Flush the ACK */
            break;
        }
        Mtrace("!");
    }

    Mtrace("Xup_almost");
    if ((done != -1) && (xip->flags & YMODEM)) { 
        xip->sno = 0;
        memset((char *)buf,0,PKTLEN_128);
        pktlen = xip->pktlen;
        xip->pktlen = PKTLEN_128;
        putPacket(buf,xip);
        xip->pktlen = pktlen;
    }
    Mtrace("Xup_done.");
    return(0);
}


/* Xdown():
 * Called when a transfer from host to target is being made (considered
 * an download).
 */

static int
Xdown(struct xinfo *xip)
{
    long    timeout;
    char    c, *tmppkt;
    int     done;

    tmppkt = malloc(PKTLEN_1K);
    if (!tmppkt) {
        Mtrace("malloc failed");
        return(-1);
    }

nextfile:
    if (xip->flags & YMODEM)
        xip->sno = 0x00;
    else
        xip->sno = 0x01;
    xip->pktcnt = 0;
    xip->errcnt = 0;
    xip->xfertot = 0;
    xip->firsterrat = 0;

    /* Startup synchronization... */
    /* Continuously send NAK or 'C' until sender responds. */
restart:
    Mtrace("Xdown");
    while(1) {
        if (xip->flags & USECRC)
            rputchar('C');
        else
            rputchar(NAK);
        timeout = LoopsPerSecond;
        while(!gotachar() && timeout)
            timeout--;
        if (timeout)
            break;
    }

    done = 0;
    Mtrace("Got response");
    while(done == 0) {
        c = (char)getchar();
        switch(c) {
        case SOH:               /* 128-byte incoming packet */
            Mtrace("O");
            xip->pktlen = 128;
            done = getPacket(tmppkt,xip);
            if (!done && (xip->pktcnt == 1) && (xip->flags & YMODEM))
                goto restart;
            break;
        case STX:               /* 1024-byte incoming packet */
            Mtrace("T");
            xip->pktlen = 1024;
            done = getPacket(tmppkt,xip);
            if (!done && (xip->pktcnt == 1) && (xip->flags & YMODEM))
                goto restart;
            break;
        case CAN:
            Mtrace("C");
            done = -1;
            break;
        case EOT:
            Mtrace("E");
            rputchar(ACK);
            if (xip->flags & YMODEM) {
#if INCLUDE_TFS
                if (!xip->size)
                    xip->size = xip->pktcnt * xip->pktlen;
                if (xip->fname[0])
                    tfsadd(xip->fname,0,0,(uchar *)xip->base,xip->size);
                xip->dataddr = xip->base;
#endif
                goto nextfile;
            }
            else {
                done = xip->xfertot;
                printf("\nRcvd %d pkt%c (%d bytes)\n",xip->pktcnt,
                        xip->pktcnt > 1 ? 's' : ' ',xip->xfertot);
            }
            break;
        case ESC:       /* User-invoked abort */
            Mtrace("X");
            done = -1;
            break;
        default:
            Mtrace("<%02x>",c);
            done = -1;
            break;
        }
        Mtrace("!");
    }
    if (xip->flags & VERIFY) {
        if (xip->errcnt)
            printf("%d errors, first at 0x%lx\n",
                xip->errcnt,(ulong)(xip->firsterrat));
        else
            printf("verification passed\n");
    }
    free(tmppkt);
    return(done);
}


#endif