1999/0603/port/qio.c (diff list | history)

1999/0603/sys/src/9/port/qio.c:1,1217 – 1999/0714/sys/src/9/port/qio.c:1,1217 (short | long | prev | next)
Bug fix: called wrong function name. rsc Fri Mar 4 12:44:25 2005
1993/0526		#include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "../port/error.h"
1997/0327		static ulong padblockcnt; static ulong concatblockcnt; static ulong pullupblockcnt; static ulong copyblockcnt; static ulong consumecnt; static ulong producecnt; static ulong qcopycnt;
1998/0605		static int debugging;
1994/0323
1997/1105		#define QDEBUG if(0)
1994/0902
1993/0526		/*
1993/0530		* IO queues */ typedef struct Queue Queue; struct Queue { Lock;
1995/0125		Block* bfirst; /* buffer */
1994/0321		Block* blast;
1993/0530
1998/0922		int len; /* bytes allocated to queue */ int dlen; /* data bytes in queue */
1993/0530		int limit; /* max bytes in queue */
1994/0902		int inilim; /* initial limit */
1993/0530		int state;
1994/0902		int noblock; /* true if writes return immediately when q full */
1993/0908		int eof; /* number of eofs read by user */
1993/0530		void (*kick)(void*); /* restart output */
1994/0321		void* arg; /* argument to kick */
1993/0530		QLock rlock; /* mutex for reading processes */ Rendez rr; /* process waiting to read */ QLock wlock; /* mutex for writing processes */ Rendez wr; /* process waiting to write */
1997/0327		char err[ERRLEN];
1993/0530		}; enum {
1997/0327		/* Queue.state */
1994/0507		Qstarve = (1<<0), /* consumer starved */ Qmsg = (1<<1), /* message stream */ Qclosed = (1<<2), Qflow = (1<<3),
1997/0925
1999/0219		Maxatomic = 32*1024,
1993/0530		};
1993/0811		void
1997/0925		ixsummary(void) {
1998/0605		debugging ^= 1;
1999/0527		iallocsummary();
1997/0925		print("pad %lud, concat %lud, pullup %lud, copy %lud\n", padblockcnt, concatblockcnt, pullupblockcnt, copyblockcnt); print("consume %lud, produce %lud, qcopy %lud\n", consumecnt, producecnt, qcopycnt);
1993/0526		}
1997/0327		/* * free a list of blocks */
1993/0526		void
1997/0327		freeblist(Block *b) { Block *next; for(; b != 0; b = next){ next = b->next; b->next = 0; freeb(b); } } /* * pad a block to the front (or the back if size is negative) */ Block* padblock(Block *bp, int size) { int n; Block *nbp;
1998/0605		QDEBUG checkb(bp, "padblock 1");
1997/0327		if(size >= 0){ if(bp->rp - bp->base >= size){ bp->rp -= size; return bp; }
1998/0605		if(bp->next)
1999/0501		panic("padblock 0x%uX", getcallerpc(&bp));
1997/0327		n = BLEN(bp);
1997/0925		padblockcnt++;
1997/0327		nbp = allocb(size+n); nbp->rp += size; nbp->wp = nbp->rp; memmove(nbp->wp, bp->rp, n); nbp->wp += n; freeb(bp); nbp->rp -= size; } else { size = -size;
1999/0311		if(bp->next)
1999/0501		panic("padblock 0x%uX", getcallerpc(&bp));
1999/0311
1997/0327		if(bp->lim - bp->wp >= size) return bp; n = BLEN(bp);
1997/0925		padblockcnt++;
1997/0327		nbp = allocb(size+n); memmove(nbp->wp, bp->rp, n); nbp->wp += n; freeb(bp); }
1998/0605		QDEBUG checkb(nbp, "padblock 1");
1997/0327		return nbp; } /* * return count of bytes in a string of blocks */ int blocklen(Block *bp) { int len; len = 0; while(bp) { len += BLEN(bp); bp = bp->next; } return len; } /* * copy the string of blocks into * a single block and free the string */ Block* concatblock(Block *bp) { int len; Block *nb, *f; if(bp->next == 0) return bp; nb = allocb(blocklen(bp)); for(f = bp; f; f = f->next) { len = BLEN(f); memmove(nb->wp, f->rp, len); nb->wp += len; } concatblockcnt += BLEN(nb); freeblist(bp);
1998/0605		QDEBUG checkb(nb, "concatblock 1");
1997/0327		return nb; } /* * make sure the first block has at least n bytes */ Block* pullupblock(Block *bp, int n) { int i; Block *nbp; /* * this should almost always be true, it's * just to avoid every caller checking. */ if(BLEN(bp) >= n) return bp; /* * if not enough room in the first block, * add another to the front of the list. */ if(bp->lim - bp->rp < n){ nbp = allocb(n); nbp->next = bp; bp = nbp; } /* * copy bytes from the trailing blocks into the first */ n -= BLEN(bp); while(nbp = bp->next){ i = BLEN(nbp); if(i > n) { memmove(bp->wp, nbp->rp, n);
1997/0925		pullupblockcnt++;
1997/0327		bp->wp += n; nbp->rp += n;
1998/0605		QDEBUG checkb(bp, "pullupblock 1");
1997/0327		return bp; } else { memmove(bp->wp, nbp->rp, i);
1997/0925		pullupblockcnt++;
1997/0327		bp->wp += i; bp->next = nbp->next; nbp->next = 0; freeb(nbp); n -= i;
1998/0605		if(n == 0){ QDEBUG checkb(bp, "pullupblock 2");
1997/0327		return bp;
1998/0605		}
1997/0327		} } freeb(bp); return 0; } /* * trim to len bytes starting at offset */ Block * trimblock(Block *bp, int offset, int len) { ulong l; Block *nb, *startb;
1998/0605		QDEBUG checkb(bp, "trimblock 1");
1997/0327		if(blocklen(bp) < offset+len) { freeblist(bp); return nil; } while((l = BLEN(bp)) < offset) { offset -= l; nb = bp->next; bp->next = nil; freeb(bp); bp = nb; } startb = bp; bp->rp += offset; while((l = BLEN(bp)) < len) { len -= l; bp = bp->next; } bp->wp -= (BLEN(bp) - len); if(bp->next) { freeblist(bp->next); bp->next = nil; } return startb; } /* * copy 'count' bytes into a new block */ Block* copyblock(Block *bp, int count) { int l; Block *nbp;
1998/0605		QDEBUG checkb(bp, "copyblock 0");
1997/0327		nbp = allocb(count); for(; count > 0 && bp != 0; bp = bp->next){ l = BLEN(bp); if(l > count) l = count; memmove(nbp->wp, bp->rp, l); nbp->wp += l; count -= l; } if(count > 0){ memset(nbp->wp, 0, count); nbp->wp += count; }
1997/0925		copyblockcnt++;
1998/0605		QDEBUG checkb(nbp, "copyblock 1");
1997/0327		return nbp; }
1997/0925		Block* adjustblock(Block* bp, int len) { int n;
1997/1007		Block *nbp;
1997/0925		if(len < 0){ freeb(bp); return nil; }
1997/1007		if(bp->rp+len > bp->lim){ nbp = copyblock(bp, len); freeblist(bp);
1998/0605		QDEBUG checkb(nbp, "adjustblock 1");
1997/1007		return nbp; }
1997/0925		n = BLEN(bp); if(len > n) memset(bp->wp, 0, len-n); bp->wp = bp->rp+len;
1998/0605		QDEBUG checkb(bp, "adjustblock 2");
1997/0925		return bp; }
1997/0327		/* * throw away up to count bytes from a * list of blocks. Return count of bytes * thrown away. */ int pullblock(Block **bph, int count) { Block *bp; int n, bytes; bytes = 0; if(bph == nil) return 0; while(*bph != nil && count != 0) { bp = *bph; n = BLEN(bp); if(count < n) n = count; bytes += n; count -= n; bp->rp += n;
1998/0605		QDEBUG checkb(bp, "pullblock ");
1997/0327		if(BLEN(bp) == 0) { *bph = bp->next; bp->next = nil; freeb(bp); } } return bytes;
1995/0902		} /*
1997/0327		* get next block from a queue, return null if nothing there
1995/0902		*/ Block*
1997/0327		qget(Queue *q)
1995/0902		{
1997/0327		int dowakeup; Block *b;
1995/0902
1997/0327		/* sync with qwrite */ ilock(q);
1995/0902
1997/0327		b = q->bfirst; if(b == 0){ q->state |= Qstarve; iunlock(q); return 0; } q->bfirst = b->next; b->next = 0;
1998/0918		q->len -= BALLOC(b);
1998/0922		q->dlen -= BLEN(b);
1998/0605		QDEBUG checkb(b, "qget");
1995/1121
1997/0327		/* if writer flow controlled, restart */ if((q->state & Qflow) && q->len < q->limit/2){ q->state &= ~Qflow; dowakeup = 1; } else dowakeup = 0;
1995/1121
1997/0327		iunlock(q); if(dowakeup) wakeup(&q->wr); return b; } /* * throw away the next 'len' bytes in the queue */ void qdiscard(Queue *q, int len) { Block *b; int dowakeup, n, sofar;
1997/0410		ilock(q);
1997/0327		for(sofar = 0; sofar < len; sofar += n){ b = q->bfirst; if(b == nil) break;
1998/0605		QDEBUG checkb(b, "qdiscard");
1997/0327		n = BLEN(b); if(n <= len - sofar){ q->bfirst = b->next; b->next = 0;
1998/0918		q->len -= BALLOC(b);
1998/0922		q->dlen -= BLEN(b);
1997/0327		freeb(b); } else { n = len - sofar; b->rp += n;
1998/0922		q->dlen -= n;
1997/0327		}
1995/1121		}
1997/0327		/* if writer flow controlled, restart */ if((q->state & Qflow) && q->len < q->limit/2){ q->state &= ~Qflow; dowakeup = 1; } else dowakeup = 0;
1997/0410		iunlock(q);
1997/0327		if(dowakeup) wakeup(&q->wr);
1993/0526		} /*
1994/0322		* Interrupt level copy out of a queue, return # bytes copied.
1993/0526		*/ int
1993/0601		qconsume(Queue *q, void *vp, int len)
1993/0526		{ Block *b;
1993/0528		int n, dowakeup;
1993/0601		uchar *p = vp;
1999/0115		Block *tofree = nil;
1993/0526
1993/0527		/* sync with qwrite */
1997/0410		ilock(q);
1993/0527
1994/1124		for(;;) { b = q->bfirst; if(b == 0){ q->state |= Qstarve;
1997/0410		iunlock(q);
1994/1124		return -1; } QDEBUG checkb(b, "qconsume 1");
1993/0528
1994/1124		n = BLEN(b); if(n > 0) break; q->bfirst = b->next;
1998/0918		q->len -= BALLOC(b);
1999/0115		/* remember to free this */ b->next = tofree; tofree = b;
1994/1124		};
1993/0526		if(n < len) len = n; memmove(p, b->rp, len);
1997/0327		consumecnt += n;
1993/0527		if((q->state & Qmsg) || len == n)
1993/0526		q->bfirst = b->next;
1994/0222		b->rp += len;
1998/0922		q->dlen -= len;
1993/0526
1999/0115		/* discard the block if we're done with it */ if((q->state & Qmsg) || len == n){ b->next = 0; q->len -= BALLOC(b); q->dlen -= BLEN(b); /* remember to free this */ b->next = tofree; tofree = b; }
1993/0528		/* if writer flow controlled, restart */ if((q->state & Qflow) && q->len < q->limit/2){ q->state &= ~Qflow; dowakeup = 1; } else dowakeup = 0;
1993/0526
1997/0410		iunlock(q);
1993/0526
1993/0528		if(dowakeup) wakeup(&q->wr);
1999/0115		if(tofree != nil) freeblist(tofree);
1993/0526		return len; }
1993/0528		int
1994/0311		qpass(Queue *q, Block *b) {
1998/0922		int dlen, len, dowakeup;
1994/0311		/* sync with qread */ dowakeup = 0;
1994/0323		ilock(q);
1997/0404		if(q->len >= q->limit){
1998/0918		freeblist(b);
1997/0404		iunlock(q); return -1; }
1994/0311
1997/0327		/* add buffer to queue */
1994/0311		if(q->bfirst) q->blast->next = b; else q->bfirst = b;
1998/0918		len = BALLOC(b);
1998/0922		dlen = BLEN(b);
1997/0327		QDEBUG checkb(b, "qpass"); while(b->next){ b = b->next; QDEBUG checkb(b, "qpass");
1998/0918		len += BALLOC(b);
1998/0922		dlen += BLEN(b);
1997/0327		}
1994/0311		q->blast = b; q->len += len;
1998/0922		q->dlen += dlen;
1994/0311
1994/0418		if(q->len >= q->limit/2)
1994/0324		q->state |= Qflow;
1994/0311		if(q->state & Qstarve){ q->state &= ~Qstarve; dowakeup = 1; }
1994/0323		iunlock(q);
1994/0311
1994/1117		if(dowakeup)
1994/0311		wakeup(&q->rr); return len; } int
1998/0918		qpassnolim(Queue *q, Block *b) {
1998/0922		int dlen, len, dowakeup;
1998/0918		/* sync with qread */ dowakeup = 0; ilock(q); /* add buffer to queue */ if(q->bfirst) q->blast->next = b; else q->bfirst = b; len = BALLOC(b);
1998/0922		dlen = BLEN(b);
1998/0918		QDEBUG checkb(b, "qpass"); while(b->next){ b = b->next; QDEBUG checkb(b, "qpass"); len += BALLOC(b);
1998/0922		dlen += BLEN(b);
1998/0918		} q->blast = b; q->len += len;
1998/0922		q->dlen += dlen;
1998/0918		if(q->len >= q->limit/2) q->state |= Qflow; if(q->state & Qstarve){ q->state &= ~Qstarve; dowakeup = 1; } iunlock(q); if(dowakeup) wakeup(&q->rr); return len; } /* * if the allocated space is way out of line with the used * space, reallocate to a smaller block */ Block* packblock(Block *bp) {
1998/0923		Block **l, *nbp; int n;
1998/0918
1998/0923		for(l = &bp; *l; l = &(*l)->next){ nbp = *l; n = BLEN(nbp); if((n<<2) < BALLOC(nbp)){ *l = allocb(n); memmove((*l)->wp, nbp->rp, n); (*l)->wp += n; (*l)->next = nbp->next; freeb(nbp); }
1998/0918		} return bp; } int
1993/0601		qproduce(Queue *q, void *vp, int len)
1993/0526		{ Block *b;
1995/0714		int dowakeup;
1993/0601		uchar *p = vp;
1993/0526
1993/0527		/* sync with qread */
1994/0208		dowakeup = 0;
1997/0410		ilock(q);
1993/0527
1993/0526		/* no waiting receivers, room in buffer? */ if(q->len >= q->limit){
1994/1116		q->state |= Qflow;
1997/0410		iunlock(q);
1993/0526		return -1; } /* save in buffer */
1994/0222		b = iallocb(len); if(b == 0){
1997/0410		iunlock(q);
1994/1117		return 0;
1993/0526		}
1994/0222		memmove(b->wp, p, len);
1997/0327		producecnt += len;
1994/0222		b->wp += len; if(q->bfirst) q->blast->next = b; else q->bfirst = b; q->blast = b;
1997/0327		/* b->next = 0; done by iallocb() */
1998/0918		q->len += BALLOC(b);
1998/0922		q->dlen += BLEN(b);
1994/0902		QDEBUG checkb(b, "qproduce");
1994/0222
1993/0528		if(q->state & Qstarve){ q->state &= ~Qstarve; dowakeup = 1;
1994/0208		}
1999/0115		if(q->len >= q->limit) q->state |= Qflow;
1997/0410		iunlock(q);
1993/0527
1994/1117		if(dowakeup)
1993/0528		wakeup(&q->rr);
1993/0526		return len; } /*
1997/0327		* copy from offset in the queue */ Block* qcopy(Queue *q, int len, ulong offset) { int sofar; int n; Block *b, *nb; uchar *p; nb = allocb(len);
1997/0410		ilock(q);
1997/0327		/* go to offset */ b = q->bfirst; for(sofar = 0; ; sofar += n){ if(b == nil){
1997/0410		iunlock(q);
1997/0327		return nb; } n = BLEN(b); if(sofar + n > offset){ p = b->rp + offset - sofar; n -= offset - sofar; break; }
1998/0605		QDEBUG checkb(b, "qcopy");
1997/0327		b = b->next; } /* copy bytes from there */ for(sofar = 0; sofar < len;){ if(n > len - sofar) n = len - sofar; memmove(nb->wp, p, n); qcopycnt += n; sofar += n; nb->wp += n; b = b->next; if(b == nil) break; n = BLEN(b); p = b->rp; }
1997/0410		iunlock(q);
1997/0327		return nb; } /*
1993/0526		* called by non-interrupt code */ Queue*
1993/0530		qopen(int limit, int msg, void (*kick)(void*), void *arg)
1993/0526		{ Queue *q; q = malloc(sizeof(Queue)); if(q == 0)
1993/0528		return 0;
1998/0328		ilock(q);
1994/0902		q->limit = q->inilim = limit;
1993/0526		q->kick = kick; q->arg = arg;
1993/0530		q->state = msg ? Qmsg : 0;
1993/0601		q->state |= Qstarve;
1993/0908		q->eof = 0;
1998/0703		q->noblock = 0;
1998/0328		iunlock(q);
1993/0526		return q; } static int
1993/0528		notempty(void *a)
1993/0526		{
1993/0528		Queue *q = a;
1993/0526
1994/0323		return (q->state & Qclosed) || q->bfirst != 0;
1993/0526		}
1993/0528		/*
1995/0714		* get next block from a queue (up to a limit)
1993/0528		*/
1995/0714		Block* qbread(Queue *q, int len)
1993/0526		{
1995/0714		Block *b, *nb;
1994/1116		int n, dowakeup;
1993/0526		qlock(&q->rlock);
1993/0527		if(waserror()){ qunlock(&q->rlock); nexterror(); }
1993/0526
1993/0528		/* wait for data */ for(;;){ /* sync with qwrite/qproduce */
1994/0323		ilock(q);
1993/0526
1993/0728		b = q->bfirst;
1997/0327		if(b){ QDEBUG checkb(b, "qbread 0");
1993/0728		break;
1997/0327		}
1993/0728
1993/0528		if(q->state & Qclosed){
1994/0323		iunlock(q);
1993/0908		poperror(); qunlock(&q->rlock); if(++q->eof > 3)
1997/0327		error(q->err);
1993/0528		return 0;
1993/0527		}
1995/0714		q->state |= Qstarve; /* flag requesting producer to wake me */ iunlock(q); sleep(&q->rr, notempty, q);
1993/0526		}
1993/0528		/* remove a buffered block */ q->bfirst = b->next;
1997/0327		b->next = 0;
1993/0528		n = BLEN(b);
1998/0922		q->dlen -= n;
1998/0918		q->len -= BALLOC(b);
1997/0327		QDEBUG checkb(b, "qbread 1");
1993/0528
1997/1102		/* split block if it's too big and this is not a message-oriented queue */
1995/0714		nb = b; if(n > len){ if((q->state&Qmsg) == 0){
1995/0917		iunlock(q);
1995/0714		n -= len; b = allocb(n); memmove(b->wp, nb->rp+len, n); b->wp += n;
1993/0526
1995/0917		ilock(q);
1995/0714		b->next = q->bfirst; if(q->bfirst == 0) q->blast = b; q->bfirst = b;
1998/0918		q->len += BALLOC(b);
1998/0922		q->dlen += n;
1995/0714		} nb->wp = nb->rp + len;
1993/0526		}
1999/0115		/* if writer flow controlled, restart */ if((q->state & Qflow) && q->len < q->limit/2){ q->state &= ~Qflow; dowakeup = 1; } else dowakeup = 0;
1993/0527
1995/0714		iunlock(q); /* wakeup flow controlled writers */
1994/0324		if(dowakeup){ if(q->kick)
1997/0327		q->kick(q->arg);
1993/0528		wakeup(&q->wr);
1994/0324		}
1993/0528
1993/0527		poperror();
1993/0526		qunlock(&q->rlock);
1995/0714		return nb;
1993/0526		}
1995/0714		/* * read a queue. if no data is queued, post a Block * and wait on its Rendez. */ long qread(Queue *q, void *vp, int len) { Block *b; b = qbread(q, len); if(b == 0) return 0; len = BLEN(b); memmove(vp, b->rp, len); freeb(b); return len; }
1993/0528		static int qnotfull(void *a)
1993/0526		{
1993/0528		Queue *q = a;
1993/0526
1994/0215		return q->len < q->limit || (q->state & Qclosed);
1993/0528		}
1993/0527
1993/0528		/*
1995/0714		* add a block to a queue obeying flow control
1993/0528		*/ long
1995/0714		qbwrite(Queue *q, Block *b)
1993/0528		{
1995/0714		int n, dowakeup;
1993/0526
1994/0208		dowakeup = 0;
1995/0714		n = BLEN(b);
1998/0328		qlock(&q->wlock);
1994/0208		if(waserror()){ qunlock(&q->wlock); nexterror();
1994/0804		}
1994/0208
1995/0714		/* flow control */
1998/0328		for(;;){ ilock(q); if(q->state & Qclosed){ iunlock(q); freeb(b); error(q->err); } if(q->len < q->limit) break;
1995/0714		if(q->noblock){
1998/0328		iunlock(q);
1995/0714		freeb(b);
1993/1227		qunlock(&q->wlock);
1994/0208		poperror();
1995/0714		return n;
1993/1227		}
1998/0328
1995/0714		q->state |= Qflow;
1998/0328		iunlock(q);
1995/0714		sleep(&q->wr, qnotfull, q);
1993/0526		}
1995/0714		if(q->bfirst) q->blast->next = b; else q->bfirst = b; q->blast = b;
1997/0327		b->next = 0;
1998/0918		q->len += BALLOC(b);
1998/0922		q->dlen += n;
1998/0605		QDEBUG checkb(b, "qbwrite");
1995/0714		if(q->state & Qstarve){ q->state &= ~Qstarve; dowakeup = 1; } iunlock(q); if(dowakeup){ if(q->kick)
1997/0327		q->kick(q->arg);
1995/0714		wakeup(&q->rr); } qunlock(&q->wlock); poperror(); return n; } /*
1999/0219		* write to a queue. only Maxatomic bytes at a time is atomic.
1995/0714		*/
1997/0327		int
1995/0714		qwrite(Queue *q, void *vp, int len) { int n, sofar; Block *b; uchar *p = vp;
1997/0327		QDEBUG if(islo() == 0)
1999/0501		print("qwrite hi %lux\n", getcallerpc(&q));
1995/0714		sofar = 0;
1994/0208		do { n = len-sofar;
1999/0219		if(n > Maxatomic) n = Maxatomic;
1993/0528
1994/0208		b = allocb(n);
1999/0603		tagwithpc(b, (up->text[0]<<24)|(up->text[1]<<16)|(up->text[2]<<8)|up->text[3]);
1999/0714		setmalloctag(b, (up->text[0]<<24)|(up->text[1]<<16)|(up->text[2]<<8)|up->text[3]);
1994/0804		if(waserror()){ freeb(b); nexterror(); }
1994/0208		memmove(b->wp, p+sofar, n);
1995/0714		poperror();
1994/0208		b->wp += n;
1994/0929
1995/0714		qbwrite(q, b);
1994/0929
1994/0208		sofar += n; } while(sofar < len && (q->state & Qmsg) == 0);
1993/0528
1993/0526		return len; }
1993/0528		/*
1995/0714		* used by print() to write to a queue. Since we may be splhi or not in * a process, don't qlock.
1994/1124		*/
1997/0327		int
1994/1124		qiwrite(Queue *q, void *vp, int len) { int n, sofar, dowakeup; Block *b; uchar *p = vp; dowakeup = 0; sofar = 0; do { n = len-sofar;
1999/0219		if(n > Maxatomic) n = Maxatomic;
1994/1124		b = allocb(n); memmove(b->wp, p+sofar, n); b->wp += n; ilock(q); QDEBUG checkb(b, "qiwrite");
1995/0714		if(q->bfirst) q->blast->next = b; else q->bfirst = b; q->blast = b;
1998/0918		q->len += BALLOC(b);
1998/0922		q->dlen += n;
1994/1124
1995/0714		if(q->state & Qstarve){ q->state &= ~Qstarve; dowakeup = 1;
1994/1124		} iunlock(q); if(dowakeup){ if(q->kick)
1997/0327		q->kick(q->arg);
1994/1124		wakeup(&q->rr); } sofar += n; } while(sofar < len && (q->state & Qmsg) == 0); return len; } /*
1997/0327		* be extremely careful when calling this, * as there is no reference accounting */ void qfree(Queue *q) { qclose(q); free(q); } /*
1993/0528		* Mark a queue as closed. No further IO is permitted. * All blocks are released. */ void qclose(Queue *q)
1993/0527		{
1997/0327		Block *bfirst;
1993/0527
1997/0327		if(q == nil) return;
1993/0528		/* mark it */
1994/0323		ilock(q);
1993/0528		q->state |= Qclosed;
1997/0806		q->state &= ~(Qflow|Qstarve);
1997/0327		strcpy(q->err, Ehungup);
1993/0528		bfirst = q->bfirst; q->bfirst = 0;
1994/0219		q->len = 0;
1998/0929		q->dlen = 0;
1994/0927		q->noblock = 0;
1994/0323		iunlock(q);
1993/0527
1993/0528		/* free queued blocks */
1997/0327		freeblist(bfirst);
1993/0526
1993/0528		/* wake up readers/writers */ wakeup(&q->rr); wakeup(&q->wr); }
1993/0527
1993/0528		/* * Mark a queue as closed. Wakeup any readers. Don't remove queued * blocks. */ void
1997/0327		qhangup(Queue *q, char *msg)
1993/0528		{ /* mark it */
1994/0323		ilock(q);
1993/0528		q->state |= Qclosed;
1997/0327		if(msg == 0 || *msg == 0) strcpy(q->err, Ehungup); else strncpy(q->err, msg, ERRLEN-1);
1994/0323		iunlock(q);
1993/0527
1993/0528		/* wake up readers/writers */ wakeup(&q->rr); wakeup(&q->wr);
1998/1127		} /* * return non-zero if the q is hungup */ int qisclosed(Queue *q) { return q->state & Qclosed;
1993/0528		} /* * mark a queue as no longer hung up */ void qreopen(Queue *q) {
1998/0328		ilock(q);
1993/0528		q->state &= ~Qclosed;
1993/0601		q->state |= Qstarve;
1993/0908		q->eof = 0;
1994/0902		q->limit = q->inilim;
1998/0328		iunlock(q);
1993/0530		} /* * return bytes queued */ int qlen(Queue *q) {
1998/0922		return q->dlen;
1993/0601		} /*
1994/0327		* return space remaining before flow control */ int qwindow(Queue *q) { int l; l = q->limit - q->len; if(l < 0) l = 0; return l; } /*
1993/0601		* return true if we can read without blocking */ int qcanread(Queue *q) { return q->bfirst!=0;
1994/0902		} /* * change queue limit */ void qsetlimit(Queue *q, int limit) { q->limit = limit; } /* * set blocking/nonblocking */ void qnoblock(Queue *q, int onoff) { q->noblock = onoff;
1994/0927		} /* * flush the output queue */ void qflush(Queue *q) {
1997/0327		Block *bfirst;
1994/0927		/* mark it */ ilock(q); bfirst = q->bfirst; q->bfirst = 0; q->len = 0;
1998/0922		q->dlen = 0;
1994/0927		iunlock(q); /* free queued blocks */
1997/0327		freeblist(bfirst);
1994/0927		/* wake up readers/writers */ wakeup(&q->wr);
1994/1124		} int
1997/0327		qfull(Queue *q)
1994/1124		{
1997/0327		return q->state & Qflow;
1993/0526		}
1995/1217
1997/0327		int qstate(Queue *q)
1995/1217		{
1997/0327		return q->state;
1995/1217		}