23 files changed, 388 insertions(+), 131 deletions(-)

M alphapc/trap.c
M bitsy/devpenmouse.c
M bitsy/l.s
M bitsy/power.c
M bitsy/trap.c
M mtx/trap.c
M pc/devvga.c
M pc/ether79c970.c
M pc/screen.c
M pc/sdata.c
M pc/trap.c
M pc/uarti8250.c
M pc/vga.c
A pc/vgavmware.c
M port/allocb.c
M port/chan.c
M port/dev.c
M port/devdup.c
M port/devmnt.c
M port/portdat.h
M port/proc.c
M port/sysfile.c
M port/sysproc.c

@@ 703,6 703,8 @@ print("bad sys call %d pc %lux\n", up->scallnr, (ulong)ur->pc);
 	poperror();
 
 error:
+	/* failure: save the error buffer for errstr */
+	kstrcpy(up->syserror, up->error, sizeof up->syserror);
 	up->nerrlab = 0;
 	up->psstate = 0;
 	up->insyscall = 0;

@@ 92,7 92,10 @@ extern	Memimage*	gscreen;
 
 void
 penbutton(int up, int b) {
-	if (b & 0x20) {
+	// button 5 (side button) immediately causes an event
+	// when the pen is down (button 1), other buttons also
+	// cause events, allowing chording with button 1
+	if ((b & 0x20) || (mouse.buttons & 0x1)) {
 		if (up)
 			mouse.buttons &= ~b;
 		else

@@ 688,7 688,8 @@ TEXT power_down(SB), $-4
 	MOVW	R2,0x10(R3)
 	MOVW	$0,R2
 	MOVW	R2,0x18(R3)
-	MOVW	$power_resume+0(SB),R2
+/*	MOVW	$power_resume+0(SB),R2	*/
+	MOVW	$0,R2
 	MOVW	R2,0x8(R3)
 	MOVW	$0,R2
 	MOVW	R2,0x4(R6)

@@ 275,7 275,6 @@ powerinit(void)
 void
 idlehands(void)
 {
-#ifdef notdef
 	char *msgb = "idlehands called with splhi\n";
 	char *msga = "doze returns with splhi\n";
 


@@ 288,6 287,5 @@ idlehands(void)
 		serialputs(msgb, strlen(msgb));
 		spllo();
 	}
-#endif
 }
 

@@ 462,6 462,9 @@ syscall(Ureg* ureg)
 
 		ret = systab[scallnr](up->s.args);
 		poperror();
+	}else{
+		/* failure: save the error buffer for errstr */
+		kstrcpy(up->syserror, up->error, sizeof up->syserror);
 	}
 	if(up->nerrlab){
 		print("bad errstack [%d]: %d extra\n", scallnr, up->nerrlab);

@@ 653,6 653,9 @@ syscall(Ureg* ureg)
 
 		ret = systab[scallnr](up->s.args);
 		poperror();
+	}else{
+		/* failure: save the error buffer for errstr */
+		kstrcpy(up->syserror, up->error, sizeof up->syserror);
 	}
 	if(up->nerrlab){
 		print("bad errstack [%d]: %d extra\n", scallnr, up->nerrlab);

@@ 276,6 276,7 @@ vgactl(char* a)
 		return;
 	}
 	else if(strcmp(field[0], "drawinit") == 0){
+		memimagedraw(scr->gscreen, scr->gscreen->r, memblack, ZP, nil, ZP);
 		if(scr && scr->dev && scr->dev->drawinit)
 			scr->dev->drawinit(scr);
 		return;

@@ 1,5 1,5 @@
 /*
- * AM79C970
+ * AMD79C970
  * PCnet-PCI Single-Chip Ethernet Controller for PCI Local Bus
  * To do:
  *	finish this rewrite


@@ 108,7 108,7 @@ enum {					/* md2 */
 };
 
 typedef struct Ctlr Ctlr;
-typedef struct Ctlr {
+struct Ctlr {
 	Lock;
 	int	port;
 	Pcidev*	pcidev;


@@ 140,28 140,49 @@ typedef struct Ctlr {
 	ulong	merr;			/* bobf is such a whiner */
 	ulong	miss;
 	ulong	babl;
-} Ctlr;
+
+	int	(*ior)(Ctlr*, int);
+	void	(*iow)(Ctlr*, int, int);
+};
 
 static Ctlr* ctlrhead;
 static Ctlr* ctlrtail;
 
-#define csr32r(c, r)	(inl((c)->port+(r)))
-#define csr32w(c, r, l)	(outl((c)->port+(r), (ulong)(l)))
+/*
+ * The Rdp, Rap, Sreset, Bdp ports are 32-bit port offset in the enumeration above.
+ * To get to 16-bit offsets, scale down with 0x10 staying the same.
+ */
+static int
+io16r(Ctlr *c, int r)
+{
+	if(r >= Rdp)
+		r = (r-Rdp)/2+Rdp;
+	return ins(c->port+r);
+}
 
 static void
-attach(Ether* ether)
+io16w(Ctlr *c, int r, int v)
 {
-	Ctlr *ctlr;
+	if(r >= Rdp)
+		r = (r-Rdp)/2+Rdp;
+	outs(c->port+r, v);
+}
 
-	ctlr = ether->ctlr;
+static int
+io32r(Ctlr *c, int r)
+{
+	return inl(c->port+r);
+}
 
-	ilock(ctlr);
-	if(ctlr->init){
-		iunlock(ctlr);
-		return;
-	}
-	csr32w(ctlr, Rdp, Iena|Strt);
-	iunlock(ctlr);
+static void
+io32w(Ctlr *c, int r, int v)
+{
+	outl(c->port+r, v);
+}
+
+static void
+attach(Ether*)
+{
 }
 
 static long


@@ 260,20 281,20 @@ promiscuous(void* arg, int on)
 	while(ctlr->ntq)
 		;
 
-	csr32w(ctlr, Rdp, Stop);
+	ctlr->iow(ctlr, Rdp, Stop);
 
-	csr32w(ctlr, Rap, 15);
-	x = csr32r(ctlr, Rdp) & ~Prom;
+	ctlr->iow(ctlr, Rap, 15);
+	x = ctlr->ior(ctlr, Rdp) & ~Prom;
 	if(on)
 		x |= Prom;
-	csr32w(ctlr, Rdp, x);
-	csr32w(ctlr, Rap, 0);
+	ctlr->iow(ctlr, Rdp, x);
+	ctlr->iow(ctlr, Rap, 0);
 
 	ringinit(ctlr);
 
 	ilock(ctlr);
 	ctlr->init = 0;
-	csr32w(ctlr, Rdp, Iena|Strt);
+	ctlr->iow(ctlr, Rdp, Iena|Strt);
 	iunlock(ctlr);
 }
 


@@ 299,7 320,7 @@ txstart(Ether* ether)
 		 * increment the software ring descriptor pointer
 		 * and tell the chip to poll.
 		 * There's no need to pad to ETHERMINTU
-		 * here as ApadXmit is set in CSR4.
+		 * here as ApadXmt is set in CSR4.
 		 */
 		dre = &ctlr->tdr[ctlr->tdrh];
 		dre->bp = bp;


@@ 307,7 328,7 @@ txstart(Ether* ether)
 		dre->md2 = 0;
 		dre->md1 = Own|Stp|Enp|(-BLEN(bp) & 0xFFFF);
 		ctlr->ntq++;
-		csr32w(ctlr, Rdp, Iena|Tdmd);
+		ctlr->iow(ctlr, Rdp, Iena|Tdmd);
 		ctlr->tdrh = NEXT(ctlr->tdrh, Ntdre);
 	}
 }


@@ 340,8 361,8 @@ interrupt(Ureg*, void* arg)
 	 * happen.
 	 */
 intrloop:
-	csr0 = csr32r(ctlr, Rdp) & 0xFFFF;
-	csr32w(ctlr, Rdp, Babl|Cerr|Miss|Merr|Rint|Tint|Iena);
+	csr0 = ctlr->ior(ctlr, Rdp) & 0xFFFF;
+	ctlr->iow(ctlr, Rdp, Babl|Cerr|Miss|Merr|Rint|Tint|Iena);
 	if(csr0 & Merr)
 		ctlr->merr++;
 	if(csr0 & Miss)


@@ 488,46 509,67 @@ reset(Ether* ether)
 	ilock(ctlr);
 	ctlr->init = 1;
 
+	io32r(ctlr, Sreset);
+	io16r(ctlr, Sreset);
+
+	if(io16w(ctlr, Rap, 0), io16r(ctlr, Rdp) == 4){
+		ctlr->ior = io16r;
+		ctlr->iow = io16w;
+	}else if(io32w(ctlr, Rap, 0), io32r(ctlr, Rdp) == 4){
+		ctlr->ior = io32r;
+		ctlr->iow = io32w;
+	}else{
+		print("#l%d: card doesn't talk right\n", ether->ctlrno);
+		iunlock(ctlr);
+		return -1;
+	}
+
+	ctlr->iow(ctlr, Rap, 88);
+	x = ctlr->ior(ctlr, Rdp);
+	ctlr->iow(ctlr, Rap, 89);
+	x |= ctlr->ior(ctlr, Rdp)<<16;
+
+	switch(x&0xFFFFFFF){
+	case 0x2420003:	/* PCnet/PCI 79C970 */
+	case 0x2621003:	/* PCnet/PCI II 79C970A */
+		break;
+	default:
+		print("#l%d: unknown PCnet card version %.7ux\n",
+			ether->ctlrno, x&0xFFFFFFF);
+		iunlock(ctlr);
+		return -1;
+	}
+
 	/*
-	 * How to tell what mode the chip is in at this point - if it's in WORD
-	 * mode then the only 32-bit access allowed is a write to the RDP, which
-	 * forces the chip to DWORD mode; if it's in DWORD mode then only DWORD
-	 * accesses are allowed?
-	 * Assuming a DWORD write is done to the RDP, what will be overwritten as
-	 * the RAP can't reliably be accessed?
-	 *
-	 * Force DWORD mode by writing to RDP, doing a reset then writing to RDP
-	 * again. The value of RAP after a reset is 0, so the second DWORD write
-	 * will be to CSR0.
 	 * Set the software style in BCR20 to be PCnet-PCI to ensure 32-bit access.
 	 * Set the auto pad transmit in CSR4.
 	 */
-	csr32w(ctlr, Rdp, 0x00);
-	csr32r(ctlr, Sreset);
-	csr32w(ctlr, Rdp, Stop);
-
-	csr32w(ctlr, Rap, 20);
-	csr32w(ctlr, Bdp, 0x0002);
+	ctlr->iow(ctlr, Rap, 20);
+	ctlr->iow(ctlr, Bdp, 0x0002);
 
-	csr32w(ctlr, Rap, 4);
-	x = csr32r(ctlr, Rdp) & 0xFFFF;
-	csr32w(ctlr, Rdp, ApadXmt|x);
+	ctlr->iow(ctlr, Rap, 4);
+	x = ctlr->ior(ctlr, Rdp) & 0xFFFF;
+	ctlr->iow(ctlr, Rdp, ApadXmt|x);
 
-	csr32w(ctlr, Rap, 0);
+	ctlr->iow(ctlr, Rap, 0);
 
 	/*
-	 * Check if the adapter's station address is to be over-ridden.
-	 * If not, read it from the I/O-space and set in ether->ea prior to loading the
-	 * station address in the initialisation block.
+	 * Check if the adapter's station address is to be overridden.
+	 * If not, read it from the I/O-space and set in ether->ea prior to
+	 * loading the station address in the initialisation block.
 	 */
 	memset(ea, 0, Eaddrlen);
 	if(!memcmp(ea, ether->ea, Eaddrlen)){
-		x = csr32r(ctlr, Aprom);
+		x = ctlr->ior(ctlr, Aprom);
 		ether->ea[0] = x;
 		ether->ea[1] = x>>8;
-		ether->ea[2] = x>>16;
-		ether->ea[3] = x>>24;
-		x = csr32r(ctlr, Aprom+4);
+		if(ctlr->ior == io16r)
+			x = ctlr->ior(ctlr, Aprom+2);
+		else
+			x >>= 16;
+		ether->ea[2] = x;
+		ether->ea[3] = x>>8;
+		x = ctlr->ior(ctlr, Aprom+4);
 		ether->ea[4] = x;
 		ether->ea[5] = x>>8;
 	}


@@ 550,18 592,25 @@ reset(Ether* ether)
 	 * enables will be set later when attaching to the network.
 	 */
 	x = PADDR(&ctlr->iblock);
-	csr32w(ctlr, Rap, 1);
-	csr32w(ctlr, Rdp, x & 0xFFFF);
-	csr32w(ctlr, Rap, 2);
-	csr32w(ctlr, Rdp, (x>>16) & 0xFFFF);
-	csr32w(ctlr, Rap, 3);
-	csr32w(ctlr, Rdp, Idon);
-	csr32w(ctlr, Rap, 0);
-	csr32w(ctlr, Rdp, Init);
-
-	while(!(csr32r(ctlr, Rdp) & Idon))
+	ctlr->iow(ctlr, Rap, 1);
+	ctlr->iow(ctlr, Rdp, x & 0xFFFF);
+	ctlr->iow(ctlr, Rap, 2);
+	ctlr->iow(ctlr, Rdp, (x>>16) & 0xFFFF);
+	ctlr->iow(ctlr, Rap, 3);
+	ctlr->iow(ctlr, Rdp, Idon);
+	ctlr->iow(ctlr, Rap, 0);
+	ctlr->iow(ctlr, Rdp, Init);
+
+	while(!(ctlr->ior(ctlr, Rdp) & Idon))
 		;
-	csr32w(ctlr, Rdp, Idon|Stop);
+
+	/*
+	 * We used to set CSR0 to Idon|Stop here, and then
+	 * in attach change it to Iena|Strt.  Apparently the simulated
+	 * 79C970 in VMware never enables after a write of Idon|Stop,
+	 * so we enable the device here now.
+	 */
+	ctlr->iow(ctlr, Rdp, Iena|Strt);
 	ctlr->init = 0;
 	iunlock(ctlr);
 

@@ 72,9 72,6 @@ screensize(int x, int y, int z, ulong chan)
 	if(gscreen == nil)
 		return -1;
 
-/*	memset(gscreen->data->bdata, 0x15, (x*y*z+7)/8);	/* RSC BUG */
-	memfillcolor(gscreen, DRed);
-
 	scr->palettedepth = 6;	/* default */
 	scr->gscreendata = &gscreendata;
 	scr->memdefont = getmemdefont();

@@ 1590,14 1590,12 @@ atapnp(void)
 	Pcidev *p;
 	int channel, ispc87415, pi, r;
 	SDev *legacy[2], *sdev, *head, *tail;
-//int i;
 
 	legacy[0] = legacy[1] = head = tail = nil;
 	if(sdev = ataprobe(0x1F0, 0x3F4, IrqATA0)){
 		head = tail = sdev;
 		legacy[0] = sdev;
 	}
-//print("probe 1, sdev %p\n", sdev);
 	if(sdev = ataprobe(0x170, 0x374, IrqATA1)){
 		if(head != nil)
 			tail->next = sdev;


@@ 1606,7 1604,6 @@ atapnp(void)
 		tail = sdev;
 		legacy[1] = sdev;
 	}
-//print("probe 2, sdev %p\n", sdev);
 
 	p = nil;
 	while(p = pcimatch(p, 0, 0)){


@@ 1662,8 1659,6 @@ atapnp(void)
 			 */
 			break;
 		case (0x0646<<16)|0x1095:	/* CMD 646 */
-//for(i = 0; i <= 4; i++) print("bar%d: addr %lux size %d\n", i, p->mem[i].bar, p->mem[i].size);
-			break;
 		case (0x0571<<16)|0x1106:	/* VIA 82C686 */
 		case (0x0211<<16)|0x1166:	/* ServerWorks IB6566 */
 		case (0x1230<<16)|0x8086:	/* 82371FB (PIIX) */

@@ 502,6 502,9 @@ syscall(Ureg* ureg)
 
 		ret = systab[scallnr](up->s.args);
 		poperror();
+	}else{
+		/* failure: save the error buffer for errstr */
+		kstrcpy(up->syserror, up->error, sizeof up->syserror);
 	}
 	if(up->nerrlab){
 		print("bad errstack [%d]: %d extra\n", scallnr, up->nerrlab);

@@ 135,14 135,14 @@ static Uart i8250uart[2] = {
 	.name	= "COM1",
 	.freq	= UartFREQ,
 	.phys	= &i8250physuart,
-	.special=0,
+	.special= 0,
 	.next	= &i8250uart[1], },
 
 {	.regs	= &i8250ctlr[1],
 	.name	= "COM2",
 	.freq	= UartFREQ,
 	.phys	= &i8250physuart,
-	.special=0,
+	.special= 0,
 	.next	= nil, },
 };
 

@@ 189,6 189,7 @@ vgascreenwin(VGAscr* scr)
 	curpos = window.min;
 
 	screenputs = vgascreenputs;
+
 }
 
 /*

@@ 0,0 1,194 @@
+#include "u.h"
+#include "../port/lib.h"
+#include "mem.h"
+#include "dat.h"
+#include "fns.h"
+#include "io.h"
+#include "../port/error.h"
+
+#define	Image	IMAGE
+#include <draw.h>
+#include <memdraw.h>
+#include <cursor.h>
+#include "screen.h"
+
+enum {
+	PCIVMWARE	= 0x15AD,	/* PCI VID */
+
+	VMWARE1		= 0x0710,	/* PCI DID */
+	VMWARE2		= 0x0405,
+};
+
+enum {
+	Rid = 0,
+	Renable,
+	Rwidth,
+	Rheight,
+	Rmaxwidth,
+	Rmaxheight,
+	Rdepth,
+	Rbpp,
+	Rpseudocolor,
+	Rrmask,
+	Rgmask,
+	Rbmask,
+	Rbpl,
+	Rfbstart,
+	Rfboffset,
+	Rfbmaxsize,
+	Rfbsize,
+	Rcap,
+	Rmemstart,
+	Rmemsize,
+	Rconfigdone,
+	Rsync,
+	Rbusy,
+	Rguestid,
+	Rcursorid,
+	Rcursorx,
+	Rcursory,
+	Rcursoron,
+	Nreg,
+
+	Rpalette = 1024,
+};
+
+typedef struct Vmware	Vmware;
+struct Vmware {
+	ulong	mmio;
+	ulong	fb;
+
+	ulong	ra;
+	ulong	rd;
+
+	ulong	r[Nreg];
+
+	char	chan[32];
+	int	depth;
+};
+
+Vmware xvm;
+Vmware *vm=&xvm;
+
+static ulong
+vmrd(Vmware *vm, int i)
+{
+	outl(vm->ra, i);
+	return inl(vm->rd);
+}
+
+static void
+vmwr(Vmware *vm, int i, ulong v)
+{
+	outl(vm->ra, i);
+	outl(vm->rd, v);
+}
+
+static ulong
+vmwarelinear(VGAscr* scr, int* size, int* align)
+{
+	char err[64];
+	ulong aperture, oaperture;
+	int osize, oapsize, wasupamem;
+	Pcidev *p;
+	Physseg seg;
+
+	osize = *size;
+	oaperture = scr->aperture;
+	oapsize = scr->apsize;
+	wasupamem = scr->isupamem;
+
+	p = pcimatch(nil, PCIVMWARE, 0);
+	if(p == nil)
+		error("no vmware card found");
+
+	switch(p->did){
+	default:
+		snprint(err, sizeof err, "unknown vmware id %.4ux", p->did);
+		error(err);
+		
+	case VMWARE1:
+		vm->ra = 0x4560;
+		vm->rd = 0x4560+4;
+		break;
+
+	case VMWARE2:
+		vm->ra = p->mem[0].bar&~3;
+		vm->rd = vm->ra + 1;
+	}
+
+	aperture = (ulong)(vmrd(vm, Rfbstart));
+	*size = vmrd(vm, Rfbsize);
+
+	if(wasupamem)
+		upafree(oaperture, oapsize);
+	scr->isupamem = 0;
+
+	aperture = upamalloc(aperture, *size, *align);
+	if(aperture == 0){
+		if(wasupamem && upamalloc(oaperture, oapsize, 0))
+			scr->isupamem = 1;
+	}else
+		scr->isupamem = 1;
+
+	if(oaperture)
+		print("warning (BUG): redefinition of aperture does not change vmwarescreen segment\n");
+	memset(&seg, 0, sizeof(seg));
+	seg.attr = SG_PHYSICAL;
+	seg.name = smalloc(32);
+	snprint(seg.name, 32, "vmwarescreen");
+	seg.pa = aperture;
+	seg.size = osize;
+	addphysseg(&seg);
+	return aperture;
+}
+
+static void
+vmwaredisable(VGAscr*)
+{
+}
+
+static void
+vmwareload(VGAscr*, Cursor*)
+{
+}
+
+static int
+vmwaremove(VGAscr*, Point)
+{
+	return 0;
+}
+
+static void
+vmwareenable(VGAscr*)
+{
+}
+
+static void
+vmwareblank(int)
+{
+}
+
+static void
+vmwaredrawinit(VGAscr*)
+{
+}
+
+VGAdev vgavmwaredev = {
+	"vmware",
+
+	0,
+	0,
+	0,
+	vmwarelinear,
+	vmwaredrawinit,
+};
+
+VGAcur vgavmwarecur = {
+	"vmwarehwgc",
+
+	vmwareenable,
+	vmwaredisable,
+	vmwareload,
+	vmwaremove,
+};

@@ 62,12 62,11 @@ allocb(int size)
 	 */
 	if(up == nil)
 		panic("allocb without up: %uX\n", getcallerpc(&size));
-	if((b = _allocb(size)) == nil)
-{
-xsummary();
-mallocsummary();
+	if((b = _allocb(size)) == nil){
+		xsummary();
+		mallocsummary();
 		panic("allocb: no memory for %d bytes\n", size);
-}
+	}
 	setmalloctag(b, getcallerpc(&size));
 
 	return b;

@@ 237,6 237,7 @@ newchan(void)
 	c->iounit = 0;
 	c->umh = 0;
 	c->uri = 0;
+	c->dri = 0;
 	c->aux = 0;
 	c->mchan = 0;
 	c->mcp = 0;


@@ 546,9 547,9 @@ cunmount(Chan *mnt, Chan *mounted)
 	Mount *f, **p;
 
 if(mnt->umh)	/* should not happen */
-	print("cunmount newp extra umh\n");
+	print("cunmount newp extra umh %p has %p\n", mnt, mnt->umh);
 if(mounted && mounted->umh)
-	print("cunmount old extra umh\n");
+	print("cunmount old extra umh %p has %p\n", mounted, mounted->umh);
 
 	pg = up->pgrp;
 	wlock(&pg->ns);


@@ 771,7 772,7 @@ walk(Chan **cp, char **names, int nnames, int nomount)
 				runlock(&mh->lock);
 				nexterror();
 			}
-			for(f = mh->mount; f; f = f->next)
+			for(f = mh->mount->next; f; f = f->next)
 				if((wq = devtab[f->to->type]->walk(f->to, nil, names, ntry)) != nil)
 					break;
 			poperror();


@@ 969,6 970,7 @@ namec(char *aname, int amode, int omode, ulong perm)
 	Elemlist e;
 	Rune r;
 	Mhead *m;
+	char createerr[ERRMAX];
 	char *name;
 
 	name = aname;


@@ 1086,29 1088,36 @@ namec(char *aname, int amode, int omode, ulong perm)
 		cnameclose(c->name);
 		c->name = cname;
 
-		if(amode == Aremove){
+		switch(amode){
+		case Aremove:
 			putmhead(m);
 			break;
-		}
 
+		case Aopen:
+		case Acreate:
 if(c->umh != nil){
 	print("cunique umh\n");
 	putmhead(c->umh);
 }
-		c->umh = m;
+			if(c->qid.type&QTDIR)
+				c->umh = m;
+			else
+				putmhead(m);
 
-		/* save registers else error() in open has wrong value of c saved */
-		saveregisters();
+			/* save registers else error() in open has wrong value of c saved */
+			saveregisters();
 
-		if(omode == OEXEC)
-			c->flag &= ~CCACHE;
+			if(omode == OEXEC)
+				c->flag &= ~CCACHE;
 
-		c = devtab[c->type]->open(c, omode&~OCEXEC);
+			c = devtab[c->type]->open(c, omode&~OCEXEC);
 
-		if(omode & OCEXEC)
-			c->flag |= CCEXEC;
-		if(omode & ORCLOSE)
-			c->flag |= CRCLOSE;
+			if(omode & OCEXEC)
+				c->flag |= CCEXEC;
+			if(omode & ORCLOSE)
+				c->flag |= CRCLOSE;
+			break;
+		}
 		break;
 
 	case Atodir:


@@ 1222,8 1231,10 @@ if(c->umh != nil){
 				putmhead(m);
 			if(omode & OEXCL)
 				nexterror();
+			/* save error */
+			kstrcpy(createerr, up->error, sizeof createerr);
 			if(walk(&c, e.elems+e.nelems-1, 1, nomount) < 0)
-				nexterror();
+				error(createerr);	/* report true error */
 			omode |= OTRUNC;
 			goto Open;
 		}


@@ 1242,6 1253,7 @@ if(c->umh != nil){
 		kstrcpy(up->genbuf, ".", sizeof up->genbuf);
 	free(e.name);
 	free(e.elems);
+
 	return c;
 }
 

@@ 254,20 254,18 @@ devstat(Chan *c, uchar *db, int n, Dirtab *tab, int ntab, Devgen *gen)
 long
 devdirread(Chan *c, char *d, long n, Dirtab *tab, int ntab, Devgen *gen)
 {
-	long k, m, dsz;
+	long m, dsz;
 	struct{
 		Dir;
 		char slop[100];
 	}dir;
 
-	k = c->offset;
-	for(m=0; m<n; k++) {
-		switch((*gen)(c, nil, tab, ntab, k, &dir)){
+	for(m=0; m<n; c->dri++) {
+		switch((*gen)(c, nil, tab, ntab, c->dri, &dir)){
 		case -1:
 			return m;
 
 		case 0:
-			c->offset++;	/* BUG??? (was DIRLEN: skip entry) */
 			break;
 
 		case 1:

@@ 103,7 103,7 @@ dupread(Chan *c, void *va, long n, vlong offset)
 {
 	char *a = va;
 	char buf[256];
-	int fd, twicefd, m;
+	int fd, twicefd;
 	Fgrp *f;
 
 	if(c->qid.type == QTDIR)

@@ 410,7 410,6 @@ mntwalk(Chan *c, Chan *nc, char **name, int nname)
 	if(waserror()) {
 		mntfree(r);
 		nexterror();
-		return nil;
 	}
 	r->request.type = Twalk;
 	r->request.fid = c->fid;

@@ 155,6 155,7 @@ struct Chan
 	Chan*	umc;			/* channel in union; held for union read */
 	QLock	umqlock;		/* serialize unionreads */
 	int	uri;			/* union read index */
+	int	dri;			/* devdirread index */
 	ulong	mountid;
 	Mntcache *mcp;			/* Mount cache pointer */
 	Mnt		*mux;		/* Mnt for clients using me for messages */


@@ 609,7 610,8 @@ struct Proc
 	Sargs	s;		/* address of this is known by db */
 	int	nerrlab;
 	Label	errlab[NERR];
-	char	error[ERRMAX];
+	char	syserror[ERRMAX];	/* last error from a system call */
+	char	error[ERRMAX];		/* reason we're unwinding the error stack */
 	char	genbuf[128];	/* buffer used e.g. for last name element from namec */
 	Chan	*slash;
 	Chan	*dot;

@@ 339,6 339,7 @@ newproc(void)
 	p->wired = 0;
 	p->ureg = 0;
 	p->error[0] = '\0';
+	p->syserror[0] = '\0';
 	kstrdup(&p->user, "*nouser");
 	kstrdup(&p->text, "*notext");
 	kstrdup(&p->args, "");


@@ 1108,7 1109,7 @@ void
 error(char *err)
 {
 	spllo();
-	strncpy(up->error, err, ERRMAX);
+	kstrcpy(up->error, err, sizeof up->error);
 	nexterror();
 }
 

@@ 557,6 557,7 @@ sseek(ulong *arg)
 	}
 	*(vlong*)arg[0] = off;
 	c->uri = 0;
+	c->dri = 0;
 	cclose(c);
 	poperror();
 }


@@ 783,7 784,7 @@ sysunmount(ulong *arg)
 			nexterror();
 		}
 		validaddr(arg[0], 1, 0);
-		cmounted = namec((char*)arg[0], Aopen, OREAD, 0);
+		cmounted = namec((char*)arg[0], Aaccess, OREAD, 0);
 		poperror();
 	}
 

@@ 633,41 633,36 @@ werrstr(char *fmt, ...)
 	va_end(va);
 }
 
-long
-syserrstr(ulong *arg)
+static long
+generrstr(char *buf, uint nbuf)
 {
-	char *e, tmp[sizeof up->error];
-	uint n;
+	char tmp[sizeof up->syserror];
 
-	n = arg[1];
-	if(n > sizeof tmp)
-		n = sizeof tmp;
-	validaddr(arg[0], n, 1);
-	e = (char*)arg[0];
-	memmove(tmp, e, n);
+	validaddr((ulong)buf, nbuf, 1);
+	if(nbuf > sizeof tmp)
+		nbuf = sizeof tmp;
+	memmove(tmp, buf, nbuf);
 	/* make sure it's NUL-terminated */
-	tmp[n-1] = '\0';
-	memmove(e, up->error, n);
-	e[n-1] = '\0';
-	memmove(up->error, tmp, n);
+	tmp[nbuf-1] = '\0';
+	memmove(buf, up->syserror, nbuf);
+	buf[nbuf-1] = '\0';
+	memmove(up->syserror, tmp, nbuf);
 	return 0;
 }
 
+long
+syserrstr(ulong *arg)
+{
+	return generrstr((char*)arg[0], arg[1]);
+}
+
 /* compatibility for old binaries */
 long
 sys_errstr(ulong *arg)
 {
-	char *e, tmp[64];
-
-	validaddr(arg[0], 64, 1);
-	e = (char*)arg[0];
-	memmove(tmp, e, 64);
-	memmove(e, up->error, 64);
-	memmove(up->error, tmp, 64);
-	return 0;
+	return generrstr((char*)arg[0], 64);
 }
 
-
 long
 sysnotify(ulong *arg)
 {