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Annotation of researchv10no/sys/io/spipe.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * stream pipe
        !             3:  */
        !             4: #include "sys/param.h"
        !             5: #include "sys/stream.h"
        !             6: #include "sys/conf.h"
        !             7: 
        !             8: extern struct  queue   *spipes[];
        !             9: extern int spcnt;
        !            10: 
        !            11: int    spsrv(), spclose();
        !            12: long   spopen();
        !            13: static struct qinit sprinit = { putq, spsrv, spopen, spclose, 128, 65 };
        !            14: struct streamtab spinfo = { &sprinit, &sprinit };
        !            15: struct cdevsw spcdev = cstrinit(&spinfo);
        !            16: 
        !            17: long
        !            18: spopen(q, dev)
        !            19: register struct queue *q;
        !            20: {
        !            21:        register d = minor(dev);
        !            22:        register struct queue *oq;
        !            23: 
        !            24:        if (d > spcnt)
        !            25:                return (0);
        !            26:        if (q->ptr) {                   /* already open */
        !            27:                if (d&01)
        !            28:                        return(0);      /* reopening master */
        !            29:                else
        !            30:                        return(1);      /* reopening slave */
        !            31:        }
        !            32:        q->flag |= QDELIM;
        !            33:        if (oq = spipes[d^01]) {
        !            34:                if (d&01)
        !            35:                        return(0);      /* master with old lingering slave */
        !            36:                WR(q)->ptr = (caddr_t)oq;
        !            37:                WR(oq)->ptr = (caddr_t)q;
        !            38:        } else if ((d&01) == 0)
        !            39:                return(0);              /* slave opened first */
        !            40:        q->ptr = (caddr_t)dev;
        !            41:        spipes[d] = q;
        !            42:        return(1);
        !            43: }
        !            44: 
        !            45: spclose(q)
        !            46: register struct queue *q;
        !            47: {
        !            48:        register struct queue *oq;
        !            49:        register struct block *bp;
        !            50: 
        !            51:        if (oq = (struct queue *)WR(q)->ptr) {
        !            52:                while (bp = getq(WR(q)))
        !            53:                        (*oq->next->qinfo->putp)(oq->next, bp);
        !            54:                putctl(oq->next, M_HANGUP);
        !            55:                WR(oq)->ptr = NULL;
        !            56:        }
        !            57:        spipes[minor((int)q->ptr)] = NULL;
        !            58: }
        !            59: 
        !            60: spsrv(q)
        !            61: register struct queue *q;
        !            62: {
        !            63:        register struct block *bp;
        !            64:        register struct queue *oq;
        !            65: 
        !            66:        if (q->flag&QREADR) {
        !            67:                oq = (struct queue *)WR(q)->ptr;
        !            68:                if (oq && (q->next->flag & QFULL) == 0)
        !            69:                        qenable(WR(oq));
        !            70:                return;
        !            71:        }
        !            72:        oq = (struct queue *)q->ptr;
        !            73:        while (bp = getq(q)) {
        !            74:                if (oq == NULL) {
        !            75:                        freeb(bp);
        !            76:                        continue;
        !            77:                }
        !            78:                if (oq->next->flag & QFULL && bp->type < QPCTL) {
        !            79:                        putbq(q, bp);
        !            80:                        return;
        !            81:                }
        !            82:                (*oq->next->qinfo->putp)(oq->next, bp);
        !            83:        }
        !            84: }

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