From e55fcb9d82497bf80d4ec37ec8d3d78d05d070b8 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Fri, 11 May 1990 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1990-05-11

---
 gnot/devmnt.c | 94 ++++++++++++++++++++++++++++++++++++---------------
 gnot/trap.c   | 26 +++++++++-----
 port/devdk.c  |  9 +++--
 port/devmnt.c | 94 ++++++++++++++++++++++++++++++++++++---------------
 port/stream.c |  7 ++--
 port/sturp.c  | 64 ++++++++++++++++++++++-------------
 power/trap.c  | 26 +++++++++-----
 7 files changed, 218 insertions(+), 102 deletions(-)

diff --git a/gnot/devmnt.c b/gnot/devmnt.c
index c12610398e67cd682e35c8f6d2ad04e56ba22e59..e2f255d751729a80adf45e58e1f95f67ec2985d4 100644
--- a/gnot/devmnt.c
+++ b/gnot/devmnt.c
@@ -555,7 +555,6 @@ mntxmit(Mnt *m, Mnthdr *mh)
 	ulong n;
 	Mntbuf *mbr, *mbw;
 	Chan *mntpt, *msg;
-	int isbit;
 
 	mbr = mballoc();
 	mbw = mballoc();
@@ -565,35 +564,21 @@ mntxmit(Mnt *m, Mnthdr *mh)
 		nexterror();
 	}
 	n = convS2M(&mh->thdr, mbw->buf);
-	isbit = 0;
-	if(devchar[m->msg->type] == '3')
-		isbit = 1;
 	/*
-	 * Avoid qlock for bit, to maximize parallelism
+	 * Bit3 does its own multiplexing.  (Well, the file server does.)
+	 * The code is different enough that it's broken out separately here.
 	 */
-	if(isbit){
-		lock(&m->use);		/* spin rather than sleep */
-		if((msg = m->msg) == 0){
-			unlock(&m->use);
-			error(0, Eshutdown);
-		}
-		incref(msg);
+	if(devchar[m->msg->type] != '3')
+		goto Normal;
+	lock(&m->use);		/* spin rather than sleep */
+	if((msg = m->msg) == 0){
 		unlock(&m->use);
-	}else{
-		qlock(m);
-		if((msg = m->msg) == 0){
-			qunlock(m);
-			error(0, Eshutdown);
-		}
-		qlock(msg);
+		error(0, Eshutdown);
 	}
+	incref(msg);
+	unlock(&m->use);
 	if(waserror()){
-		if(isbit)
-			close(msg);
-		else{
-			qunlock(m);
-			qunlock(msg);
-		}
+		close(msg);
 		nexterror();
 	}
 	if((*devtab[msg->type].write)(msg, mbw->buf, n) != n){
@@ -605,12 +590,65 @@ mntxmit(Mnt *m, Mnthdr *mh)
 	 * Read response
 	 */
 	n = (*devtab[msg->type].read)(msg, mbr->buf, BUFSIZE);
-	if(isbit)
-		close(msg);
-	else{
+	close(msg);
+	poperror();
+
+	if(convM2S(mbr->buf, &mh->rhdr, n) == 0){
+		pprint("format error in mntxmit\n");
+		error(0, Egreg);
+	}
+
+	/*
+	 * Various checks
+	 */
+	if(mh->rhdr.type != mh->thdr.type+1){
+		pprint("type mismatch %d %d\n", mh->rhdr.type, mh->thdr.type+1);
+		error(0, Egreg);
+	}
+	if(mh->rhdr.fid != mh->thdr.fid){
+		pprint("fid mismatch %d %d type %d\n", mh->rhdr.fid, mh->thdr.fid, mh->rhdr.type);
+		error(0, Egreg);
+	}
+	if(mh->rhdr.err){
+		mntpt = m->mntpt;	/* unsafe, but Errors are unsafe anyway */
+		if(mntpt)
+			error(mntpt, mh->rhdr.err);
+		error(0, Eshutdown);
+	}
+
+	/*
+	 * Copy out on read
+	 */
+	if(mh->thdr.type == Tread)
+		memcpy(mh->thdr.data, mh->rhdr.data, mh->rhdr.count);
+	mbfree(mbr);
+	mbfree(mbw);
+	poperror();
+	return;
+
+    Normal:
+	qlock(m);
+	if((msg = m->msg) == 0){
+		qunlock(m);
+		error(0, Eshutdown);
+	}
+	qlock(msg);
+	if(waserror()){
 		qunlock(m);
 		qunlock(msg);
+		nexterror();
 	}
+	if((*devtab[msg->type].write)(msg, mbw->buf, n) != n){
+		pprint("short write in mntxmit\n");
+		error(0, Egreg);
+	}
+
+	/*
+	 * Read response
+	 */
+	n = (*devtab[msg->type].read)(msg, mbr->buf, BUFSIZE);
+	qunlock(m);
+	qunlock(msg);
 	poperror();
 
 	if(convM2S(mbr->buf, &mh->rhdr, n) == 0){
diff --git a/gnot/trap.c b/gnot/trap.c
index 2b1777404ee94aeee514547787e83233e45dbe06..eb50678bcfbe94eb5234abe480dc28eef2657767 100644
--- a/gnot/trap.c
+++ b/gnot/trap.c
@@ -259,18 +259,26 @@ syscall(Ureg *aur)
 #endif
 	r0 = ur->r0;
 	sp = ur->usp;
-	if(r0 >= sizeof systab/BY2WD)
-		panic("syscall %d\n", r0);
-	if(sp & (BY2WD-1))
-		panic("syscall odd sp");
-	if(sp<(USTKTOP-BY2PG) || sp>(USTKTOP-4*BY2WD))
-		validaddr(sp, 4*BY2WD, 0);
 
 	u->nerrlab = 0;
 	ret = -1;
-	if(!waserror())
-		ret = (*systab[r0])((ulong*)(sp+BY2WD));
-/* else print("syscall %d err %d %d\n", r0, u->error.type, u->error.code); /**/
+	if(!waserror()){
+		if(r1 >= sizeof systab/BY2WD){
+			pprint("bad sys call number %d pc %lux\n", r1, ((Ureg*)UREGADDR)->pc);
+			msg = "bad sys call";
+	    Bad:
+			postnote(u->p, 1, msg, NDebug);
+			error(0, Ebadarg);
+		}
+		if(sp & (BY2WD-1)){
+			pprint("odd sp in sys call pc %lux sp %lux\n", ((Ureg*)UREGADDR)->pc, ((Ureg*)UREGADDR)->sp);
+			msg = "odd stack";
+			goto Bad;
+		}
+		if(sp<(USTKTOP-BY2PG) || sp>(USTKTOP-4*BY2WD))
+			validaddr(ur->sp, 4*BY2WD, 0);
+		ret = (*systab[r1])((ulong*)(sp+2*BY2WD));
+	}
 	u->nerrlab = 0;
 	u->p->insyscall = 0;
 	if(r0 == NOTED)	/* ugly hack */
diff --git a/port/devdk.c b/port/devdk.c
index ab2405073f74fc54f7104867b8000b38f3f1ff8d..4e3f2a168b8635eae52b85dc0ecc06dd880dcad9 100644
--- a/port/devdk.c
+++ b/port/devdk.c
@@ -329,6 +329,8 @@ dkstopen(Queue *q, Stream *s)
 	q->other->ptr = q->ptr = lp = &dp->line[s->id];
 	lp->dp = dp;
 	lp->rq = q;
+	if(lp->state == Lclosed)
+		lp->state = Lopened;
 }
 
 /*
@@ -670,7 +672,6 @@ dkopen(Chan *c, int omode)
 					continue;
 				}
 				c->qid = STREAMQID(lp-dp->line, Sctlqid);
-				qunlock(lp);
 				break;
 			}
 		}
@@ -678,6 +679,7 @@ dkopen(Chan *c, int omode)
 			error(0, Enodev);
 		streamopen(c, &dkinfo);
 		pushq(c->stream, &urpinfo);
+		qunlock(lp);
 		break;
 	case Dlistenqid:
 		/*
@@ -727,7 +729,7 @@ dkclose(Chan *c)
 {
 	Dk *dp;
 
-	/* real closing happens in lancestclose */
+	/* real closing happens in dkstclose */
 	if(c->stream)
 		streamclose(c);
 
@@ -899,7 +901,7 @@ dkcall(int type, Chan *c, char *addr, char *nuser, char *machine)
 	/*
 	 *  only dial on virgin lines
 	 */
-	if(lp->state != Lclosed)
+	if(lp->state != Lopened)
 		error(0, Ebadarg);
 
 	DPRINT("dkcall(line=%d, type=%d, dest=%s)\n", line, type, addr);
@@ -1202,6 +1204,7 @@ dklisten(Chan *c)
 		DPRINT("dklisten returns %d\n", lineno);
 		return lineno;
 	}
+	panic("dklisten terminates strangely\n");
 }
 
 /*
diff --git a/port/devmnt.c b/port/devmnt.c
index c12610398e67cd682e35c8f6d2ad04e56ba22e59..e2f255d751729a80adf45e58e1f95f67ec2985d4 100644
--- a/port/devmnt.c
+++ b/port/devmnt.c
@@ -555,7 +555,6 @@ mntxmit(Mnt *m, Mnthdr *mh)
 	ulong n;
 	Mntbuf *mbr, *mbw;
 	Chan *mntpt, *msg;
-	int isbit;
 
 	mbr = mballoc();
 	mbw = mballoc();
@@ -565,35 +564,21 @@ mntxmit(Mnt *m, Mnthdr *mh)
 		nexterror();
 	}
 	n = convS2M(&mh->thdr, mbw->buf);
-	isbit = 0;
-	if(devchar[m->msg->type] == '3')
-		isbit = 1;
 	/*
-	 * Avoid qlock for bit, to maximize parallelism
+	 * Bit3 does its own multiplexing.  (Well, the file server does.)
+	 * The code is different enough that it's broken out separately here.
 	 */
-	if(isbit){
-		lock(&m->use);		/* spin rather than sleep */
-		if((msg = m->msg) == 0){
-			unlock(&m->use);
-			error(0, Eshutdown);
-		}
-		incref(msg);
+	if(devchar[m->msg->type] != '3')
+		goto Normal;
+	lock(&m->use);		/* spin rather than sleep */
+	if((msg = m->msg) == 0){
 		unlock(&m->use);
-	}else{
-		qlock(m);
-		if((msg = m->msg) == 0){
-			qunlock(m);
-			error(0, Eshutdown);
-		}
-		qlock(msg);
+		error(0, Eshutdown);
 	}
+	incref(msg);
+	unlock(&m->use);
 	if(waserror()){
-		if(isbit)
-			close(msg);
-		else{
-			qunlock(m);
-			qunlock(msg);
-		}
+		close(msg);
 		nexterror();
 	}
 	if((*devtab[msg->type].write)(msg, mbw->buf, n) != n){
@@ -605,12 +590,65 @@ mntxmit(Mnt *m, Mnthdr *mh)
 	 * Read response
 	 */
 	n = (*devtab[msg->type].read)(msg, mbr->buf, BUFSIZE);
-	if(isbit)
-		close(msg);
-	else{
+	close(msg);
+	poperror();
+
+	if(convM2S(mbr->buf, &mh->rhdr, n) == 0){
+		pprint("format error in mntxmit\n");
+		error(0, Egreg);
+	}
+
+	/*
+	 * Various checks
+	 */
+	if(mh->rhdr.type != mh->thdr.type+1){
+		pprint("type mismatch %d %d\n", mh->rhdr.type, mh->thdr.type+1);
+		error(0, Egreg);
+	}
+	if(mh->rhdr.fid != mh->thdr.fid){
+		pprint("fid mismatch %d %d type %d\n", mh->rhdr.fid, mh->thdr.fid, mh->rhdr.type);
+		error(0, Egreg);
+	}
+	if(mh->rhdr.err){
+		mntpt = m->mntpt;	/* unsafe, but Errors are unsafe anyway */
+		if(mntpt)
+			error(mntpt, mh->rhdr.err);
+		error(0, Eshutdown);
+	}
+
+	/*
+	 * Copy out on read
+	 */
+	if(mh->thdr.type == Tread)
+		memcpy(mh->thdr.data, mh->rhdr.data, mh->rhdr.count);
+	mbfree(mbr);
+	mbfree(mbw);
+	poperror();
+	return;
+
+    Normal:
+	qlock(m);
+	if((msg = m->msg) == 0){
+		qunlock(m);
+		error(0, Eshutdown);
+	}
+	qlock(msg);
+	if(waserror()){
 		qunlock(m);
 		qunlock(msg);
+		nexterror();
 	}
+	if((*devtab[msg->type].write)(msg, mbw->buf, n) != n){
+		pprint("short write in mntxmit\n");
+		error(0, Egreg);
+	}
+
+	/*
+	 * Read response
+	 */
+	n = (*devtab[msg->type].read)(msg, mbr->buf, BUFSIZE);
+	qunlock(m);
+	qunlock(msg);
 	poperror();
 
 	if(convM2S(mbr->buf, &mh->rhdr, n) == 0){
diff --git a/port/stream.c b/port/stream.c
index a0068b560d2a53449a7916c13960eaf6632691a8..72844a3f170413f4d6968add745d53c221c551e9 100644
--- a/port/stream.c
+++ b/port/stream.c
@@ -78,13 +78,14 @@ dumpqueues(void)
 			continue;
 		for(count = 0, bp = q->first; bp; bp = bp->next)
 			count++;
-		print("%s %ux  RD count %d len %d", q->info->name, q, count, q->len);
+		print("%s %ux  R c %d l %d f %ux", q->info->name, q, count,
+			q->len, q->flag);
 		for(count = 0, bp = WR(q)->first; bp; bp = bp->next)
 			count++;
-		print("  WR count %d len %d\n", count, WR(q)->len);
+		print("  W c %d l %d f %ux\n", count, WR(q)->len, WR(q)->flag);
 	}
 	print("\n");
-	for(bcp=bclass; bcp<&bclass[Nclass-1]; bcp++){
+	for(bcp=bclass; bcp<&bclass[Nclass]; bcp++){
 		lock(bcp);
 		for(count = 0, bp = bcp->first; bp; count++, bp = bp->next)
 			;
diff --git a/port/sturp.c b/port/sturp.c
index 04ad735358670a4dc8deaff05565ffe1d810c3d1..6e110ff45bf59b33754db78207e5e172b42b286e 100644
--- a/port/sturp.c
+++ b/port/sturp.c
@@ -48,7 +48,6 @@ struct Urp {
 	int	blocks;
 
 	/* output */
-
 	QLock	xmit;		/* output lock, only one process at a time */
 	Queue	*wq;		/* output queue */
 	int	maxout;		/* maximum outstanding unacked blocks */
@@ -60,6 +59,7 @@ struct Urp {
 	Block	*xb[8];		/* the xmit window buffer */
 	QLock	xl[8];
 	ulong	timer;		/* timeout for xmit */
+	int	rexmit;
 
 	int	kstarted;
 };
@@ -168,14 +168,6 @@ isflushed(void *a)
 	up = (Urp *)a;
 	return (up->state&HUNGUP) || (up->unechoed==up->nxb && up->wq->len==0);
 }
-static int
-isdead(void *a)
-{
-	Urp *up;
-
-	up = (Urp *)a;
-	return up->kstarted == 0;
-}
 static void
 urpclose(Queue *q)
 {
@@ -219,8 +211,10 @@ urpclose(Queue *q)
 		}
 	qunlock(&up->xmit);
 
-	if(up->kstarted == 0)
+	if(up->kstarted == 0){
+		DPRINT("urpclose %ux\n", up);
 		up->state = 0;
+	}
 }
 
 /*
@@ -471,6 +465,10 @@ urpiput(Queue *q, Block *bp)
 			urpstat.rjseq++;
 			sendrej(up);
 			break;
+		} else if(q->next->len > (3*Streamhi)/2
+			|| q->next->nb > (3*Streambhi)/2) {
+			flushinput(up);
+			break;
 		}
 
 		/*
@@ -559,6 +557,7 @@ output(Urp *up)
 	ulong now;
 	Queue *q;
 	int n;
+	int i;
 
 	if(!canqlock(&up->xmit))
 		return;
@@ -607,8 +606,7 @@ output(Urp *up)
 	/*
 	 *  if a retransmit time has elapsed since a transmit, send an ENQ
 	 */
-	if(up->unechoed != up->next && NOW > up->timer){
-		DPRINT("sENQ\n");
+	if(up->unechoed!=up->next && NOW>up->timer){
 		up->timer = NOW + MSrexmit;
 		up->state &= ~REJECTING;
 		sendctl(up, ENQ);
@@ -620,11 +618,21 @@ output(Urp *up)
 	/*
 	 *  if there's a window open, push some blocks out
 	 */
-	while(WINDOW(up)>0 && up->xb[up->next]!=0 && canqlock(&up->xl[up->next])){
-		if(up->xb[up->next])
-			sendblock(up, up->next);
-		qunlock(&up->xl[up->next]);
+	if(up->rexmit){
+		up->rexmit = 0;
+		up->next = up->unechoed;
+	}
+	while(WINDOW(up)>0 && up->xb[up->next]!=0){
+		i = up->next;
+		qlock(&up->xl[i]);
+		if(waserror()){
+			qunlock(&up->xl[i]);
+			nexterror();
+		}
+		sendblock(up, i);
+		qunlock(&up->xl[i]);
 		up->next = NEXT(up->next);
+		poperror();
 	}
 	qunlock(&up->xmit);
 	poperror();
@@ -745,6 +753,7 @@ rcvack(Urp *up, int msg)
 {
 	int seqno;
 	int next;
+	int i;
 
 	seqno = msg&Nmask;
 	next = NEXT(seqno);
@@ -754,11 +763,12 @@ rcvack(Urp *up, int msg)
 	 */
 	if(IN(seqno, up->unacked, up->next)){
 		for(; up->unacked != next; up->unacked = NEXT(up->unacked)){
-			qlock(&up->xl[up->unacked]);
-			if(up->xb[up->unacked])
-				freeb(up->xb[up->unacked]);
-			up->xb[up->unacked] = 0;
-			qunlock(&up->xl[up->unacked]);
+			i = up->unacked;
+			qlock(&up->xl[i]);
+			if(up->xb[i])
+				freeb(up->xb[i]);
+			up->xb[i] = 0;
+			qunlock(&up->xl[i]);
 		}
 	}
 
@@ -786,7 +796,7 @@ rcvack(Urp *up, int msg)
 		 */
 		if(up->unechoed==next && !(up->state & REJECTING)){
 			up->state |= REJECTING;
-			up->next = next;
+			up->rexmit = 1;
 		}
 		break;
 	}
@@ -831,6 +841,7 @@ initoutput(Urp *up, int window)
 	up->unacked = 1;
 	up->next = 1;
 	up->nxb = 1;
+	up->rexmit = 0;
 
 	/*
 	 *  free any outstanding blocks
@@ -886,6 +897,7 @@ urpkproc(void *arg)
 	up = (Urp *)arg;
 
 	if(waserror()){
+		print("urpkproc error %ux\n", up);
 		up->state = 0;
 		up->kstarted = 0;
 		wakeup(&up->r);
@@ -898,10 +910,16 @@ urpkproc(void *arg)
 			if(up->state & HUNGUP)
 				break;
 		}
-		sendack(up);
+		if(up->state == 0){
+			DPRINT("urpkproc: %ux->state == 0\n", up);
+			break;
+		}
+		if(!QFULL(up->rq->next))
+			sendack(up);
 		output(up);
 		tsleep(&up->rq->r, todo, up, MSrexmit/2);
 	}
 	up->state = 0;
 	up->kstarted = 0;
+	DPRINT("urpkproc %ux\n", up);
 }
diff --git a/power/trap.c b/power/trap.c
index 3d3c94208414dd80237a94531e792e1eba4dec5e..3a93435c57798f59ce4f0d77db8ef9c0df447185 100644
--- a/power/trap.c
+++ b/power/trap.c
@@ -5,6 +5,7 @@
 #include	"fns.h"
 #include	"ureg.h"
 #include	"io.h"
+#include	"errno.h"
 
 /*
  *  vme interrupt routines
@@ -418,6 +419,7 @@ syscall(Ureg *aur)
 	ulong sp;
 	ulong r1;
 	Ureg *ur;
+	char *msg;
 
 	u->p->insyscall = 1;
 	ur = aur;
@@ -433,17 +435,25 @@ syscall(Ureg *aur)
 	spllo();
 	r1 = ur->r1;
 	sp = ur->sp;
-	if(r1 >= sizeof systab/BY2WD)
-		panic("syscall %d\n", r1);
-	if(sp & (BY2WD-1))
-		panic("syscall odd sp");
-	if(sp<(USTKTOP-BY2PG) || sp>(USTKTOP-4*BY2WD))
-		validaddr(ur->sp, 4*BY2WD, 0);
-
 	u->nerrlab = 0;
 	ret = -1;
-	if(!waserror())
+	if(!waserror()){
+		if(r1 >= sizeof systab/BY2WD){
+			pprint("bad sys call number %d pc %lux\n", r1, ((Ureg*)UREGADDR)->pc);
+			msg = "bad sys call";
+	    Bad:
+			postnote(u->p, 1, msg, NDebug);
+			error(0, Ebadarg);
+		}
+		if(sp & (BY2WD-1)){
+			pprint("odd sp in sys call pc %lux sp %lux\n", ((Ureg*)UREGADDR)->pc, ((Ureg*)UREGADDR)->sp);
+			msg = "odd stack";
+			goto Bad;
+		}
+		if(sp<(USTKTOP-BY2PG) || sp>(USTKTOP-4*BY2WD))
+			validaddr(ur->sp, 4*BY2WD, 0);
 		ret = (*systab[r1])((ulong*)(sp+2*BY2WD));
+	}
 	ur->pc += 4;
 	u->nerrlab = 0;
 	splhi();