diff --git a/qa/kern/wdir.rc b/qa/kern/wdir.rc
new file mode 100644
index 0000000..a3c4719
--- /dev/null
+++ b/qa/kern/wdir.rc
@@ -0,0 +1,33 @@
+#!/cmd/rc
+
+rm -fr /tmp/abcdefghijklmnopqrstuvwxyz/
+
+dir=/tmp/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz/abcdefghijklmnopqrstuvwxyz
+
+mkdir -p $dir
+cd $dir
+
+cwd=`{pwd}
+
+if ( ! ~ $dir $cwd ) {
+	echo FAIL: '''pwd''' returned $cwd instead of '$dir'
+	exit FAIL
+}
+
+cwd=`{cat '#0/wdir'}
+if ( ! ~ $dir $cwd ) {
+	echo FAIL: '''cat #0/wdir''' returned $cwd instead of '$dir'
+	exit FAIL
+}
+
+ppath=/proc/$pid/wdir
+
+cwd=`{cat $ppath}
+if ( ! ~ $dir $cwd ) {
+	echo FAIL: cat $ppath returned $cwd instead of '$dir'
+	exit FAIL
+}
+
+rm -fr /tmp/abcdefghijklmnopqrstuvwxyz/
+echo PASS
+exit PASS
diff --git a/qa/lib/c/asmscall.c b/qa/lib/c/asmscall.c
index 01e8d28..7ba2297 100644
--- a/qa/lib/c/asmscall.c
+++ b/qa/lib/c/asmscall.c
@@ -20,41 +20,6 @@
 
 int verbose = 1;
 
-#define asm_nsec() ({ \
-	register long __ret asm ("rax"); \
-	__asm__ __volatile__ ( \
-		"syscall" \
-		: "=r" (__ret) \
-		: "0"(19) \
-		: "cc", "rcx", "r11", "memory" \
-	); \
-	__ret; })
-
-#define asm_mount(/* int */ fd, /* int */ afd, /* char* */ old, /* int */ flag, /* char* */ aname, /* int */ mdev) ({ \
-	register long r10 asm("r10") = flag; \
-	register long r8 asm("r8") = (uintptr_t)aname; \
-	register long r9 asm("r9") = mdev; \
-	register int __ret asm ("eax"); \
-	__asm__ __volatile__ ( \
-		"syscall" \
-		: "=r" (__ret) \
-		: "0"(16), "D"(fd), "S"(afd), "d"(old), "r"(r10), "r"(r8), "r"(r9) \
-		: "cc", "rcx", "r11", "memory" \
-	); \
-	__ret; })
-
-/*
-long
-asm_nsec(void)
-{
-	register int *p1 asm ("r0");
-	register int *p2 asm ("r1");
-	register int *result asm ("r0");
-	asm ("sysint" : "=r" (result) : "0" (p1), "r" (p2));
-	return result ;
-}
-*/
-
 void
 main(void)
 {
@@ -62,9 +27,9 @@ main(void)
 	uint64_t start, end;
 	char *msg;
 
-	start = asm_nsec();
+	start = sys_nsec();
 	sleep(1);
-	end = asm_nsec();
+	end = sys_nsec();
 
 	if (end <= start)
 		ret = 1;
@@ -80,7 +45,7 @@ main(void)
 
 	int fd;
 	fd = open("#|", ORDWR);
-	asm_mount(fd, -1, "/tmp", MREPL, "", 'M');
+	sys_mount(fd, -1, "/tmp", MREPL, "", 'M');
 
 	print("PASS\n");
 	exits("PASS");
diff --git a/sys/include/libc.h b/sys/include/libc.h
index b1d5283..81c72b8 100644
--- a/sys/include/libc.h
+++ b/sys/include/libc.h
@@ -370,6 +370,7 @@ extern	int	atoi(const char*);
 extern	int32_t	atol(const char*);
 extern	int64_t	atoll(const char*);
 extern	double	charstod(int(*)(void*), void*);
+extern	int	chdir(const char *dirname);
 extern	char*	cleanname(char*);
 extern	int	decrypt(void*, void*, int);
 extern	int	encrypt(void*, void*, int);
@@ -387,7 +388,7 @@ extern	char*	getenv(const char*);
 extern	int	getfields(char*, char**, int, int, const char*);
 extern	int	gettokens(char *, char **, int, const char *);
 extern	char*	getuser(void);
-extern	char*	getwd(char*, int);
+extern	long	getwd(char*, int);
 extern	int	iounit(int);
 extern	int32_t	labs(int32_t);
 extern	double	ldexp(double, int);
diff --git a/sys/src/cmd/acme/aux/win/main.c b/sys/src/cmd/acme/aux/win/main.c
index 21b1783..7530034 100644
--- a/sys/src/cmd/acme/aux/win/main.c
+++ b/sys/src/cmd/acme/aux/win/main.c
@@ -71,7 +71,7 @@ threadmain(int argc, char *argv[])
 			name = av[0];
 	}
 
-	if(getwd(buf, sizeof buf) == 0)
+	if(getwd(buf, sizeof buf) <= 0)
 		dir = "/";
 	else
 		dir = buf;
@@ -301,7 +301,7 @@ fsloop(void* _)
 			break;
 		}
 	}
-}	
+}
 
 void
 sendit(char *s)
@@ -358,7 +358,7 @@ execevent(Window *w, Event *e, int (*command)(Window*, char*))
 		n = winread(w, e->q0, e->q1, s);
 		s[n] = '\0';
 		needfree = 1;
-	}else 
+	}else
 	if(na){
 		t = emalloc(strlen(s)+1+na+2);
 		sprint(t, "%s %s", s, ea->b);
@@ -448,7 +448,7 @@ mainctl(void *v)
 			write(w->data, e->b, e->nb);
 			pendingS += e->nr;
 			break;
-	
+
 		case 'E':	/* write to tag or body; body happens due to sendit */
 			delta = e->q1-e->q0;
 			if(e->c2=='I'){
@@ -463,7 +463,7 @@ mainctl(void *v)
 				fprint(2, "win msg: %C %C %d %d %d %d %q\n",
 					e->c1, e->c2, e->q0, e->q1, e->flag, e->nb, e->b);
 			break;
-	
+
 		case 'F':	/* generated by our actions (specifically case 'S' above) */
 			delta = e->q1-e->q0;
 			if(e->c2=='D'){
@@ -540,7 +540,7 @@ mainctl(void *v)
 				break;
 			}
 			break;
-	
+
 		case 'M':	/* mouse */
 			delta = e->q1-e->q0;
 			switch(e->c2){
@@ -548,14 +548,14 @@ mainctl(void *v)
 			case 'X':
 				execevent(w, e, command);
 				break;
-	
+
 			case 'l':	/* reflect all searches back to acme */
 			case 'L':
 				if(e->flag & 2)
 					recvp(w->cevent);
 				winwriteevent(w, e);
 				break;
-	
+
 			case 'I':
 				endpt += delta;
 				if(e->q0 < hostpt)
@@ -574,7 +574,7 @@ mainctl(void *v)
 			case 'd':	/* modify away; we don't care */
 			case 'i':
 				break;
-	
+
 			default:
 				goto Unknown;
 			}
diff --git a/sys/src/cmd/cpu.c b/sys/src/cmd/cpu.c
index 6c2bf45..bca24de 100644
--- a/sys/src/cmd/cpu.c
+++ b/sys/src/cmd/cpu.c
@@ -231,7 +231,7 @@ main(int argc, char **argv)
 	/* Tell the remote side the command to execute and where our working directory is */
 	if(cflag)
 		writestr(data, cmd, "command", 0);
-	if(getwd(dat, sizeof(dat)) == 0)
+	if(getwd(dat, sizeof(dat)) <= 0)
 		writestr(data, "NO", "dir", 0);
 	else
 		writestr(data, dat, "dir", 0);
diff --git a/sys/src/cmd/pwd.c b/sys/src/cmd/pwd.c
index b862250..15f33b8 100644
--- a/sys/src/cmd/pwd.c
+++ b/sys/src/cmd/pwd.c
@@ -1,10 +1,19 @@
 /*
- * This file is part of the UCB release of Plan 9. It is subject to the license
- * terms in the LICENSE file found in the top-level directory of this
- * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No
- * part of the UCB release of Plan 9, including this file, may be copied,
- * modified, propagated, or distributed except according to the terms contained
- * in the LICENSE file.
+ * This file is part of Jehanne.
+ *
+ * Copyright (C) 2016 Giacomo Tesio <giacomo@tesio.it>
+ *
+ * Jehanne is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2 of the License.
+ *
+ * Jehanne is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Jehanne.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #include <u.h>
@@ -16,13 +25,23 @@
 void
 main(int argc, char *argv[])
 {
-	char pathname[512];
+	long len;
+	char path[512];
+	char *ppath = path;
 
-	//USED(argc, argv);
-	if(getwd(pathname, sizeof(pathname)) == 0) {
-		fprint(2, "pwd: %r\n");
-		exits("getwd");
+	len = getwd(ppath, sizeof(path));
+	if(len == 0)
+		goto Error;
+	if(len < 0){
+		len = ~len;
+		ppath = malloc(len*sizeof(char));
+		if(getwd(ppath, len*sizeof(char)) <= 0)
+			goto Error;
 	}
-	print("%s\n", pathname);
+	print("%s\n", ppath);
 	exits(0);
+
+Error:
+	fprint(2, "pwd: %r\n");
+	exits("getwd");
 }
diff --git a/sys/src/cmd/rio/rio.c b/sys/src/cmd/rio/rio.c
index c395694..b7313ed 100644
--- a/sys/src/cmd/rio/rio.c
+++ b/sys/src/cmd/rio/rio.c
@@ -157,7 +157,7 @@ threadmain(int argc, char *argv[])
 		usage();
 	}ARGEND
 
-	if(getwd(buf, sizeof buf) == nil)
+	if(getwd(buf, sizeof buf) <= 0)
 		startdir = estrdup(".");
 	else
 		startdir = estrdup(buf);
@@ -324,7 +324,7 @@ shutdown(void * _, char *msg)
 {
 	int i;
 	static Lock shutdownlk;
-	
+
 	killprocs();
 	for(i=0; oknotes[i]; i++)
 		if(strncmp(oknotes[i], msg, strlen(oknotes[i])) == 0){
@@ -344,7 +344,7 @@ killprocs(void)
 
 	for(i=0; i<nwindow; i++)
 		if(window[i]->notefd >= 0)
-			write(window[i]->notefd, "hangup", 6); 
+			write(window[i]->notefd, "hangup", 6);
 }
 
 void
@@ -418,7 +418,7 @@ int
 whichcorner(Rectangle r, Point p)
 {
 	int i, j;
-	
+
 	i = portion(p.x, r.min.x, r.max.x);
 	j = portion(p.y, r.min.y, r.max.y);
 	return 3*j+i;
@@ -995,7 +995,7 @@ bandsize(Window *w)
 	drawborder(r, 1);
 	or = r;
 	startp = p;
-	
+
 	while(mouse->buttons==but){
 		p = onscreen(mouse->xy);
 		r = whichrect(w->screenr, p, which);
diff --git a/sys/src/cmd/tar.c b/sys/src/cmd/tar.c
index b1614d0..bb41b62 100644
--- a/sys/src/cmd/tar.c
+++ b/sys/src/cmd/tar.c
@@ -1366,7 +1366,7 @@ main(int argc, char *argv[])
 		ret = extract(argv);
 		break;
 	case Replace:
-		if (getwd(origdir, sizeof origdir) == nil)
+		if (getwd(origdir, sizeof origdir) <= 0)
 			strcpy(origdir, "/tmp");
 		ret = replace(argv);
 		break;
diff --git a/sys/src/kern/port/devdup.c b/sys/src/kern/port/devdup.c
index 82f2720..566ed0c 100644
--- a/sys/src/kern/port/devdup.c
+++ b/sys/src/kern/port/devdup.c
@@ -64,9 +64,9 @@ dupopen(Chan *c, unsigned long omode)
 	int fd, twicefd;
 
 	if(c->qid.type & QTDIR){
-		if(omode != 0)
+		if(omode != OREAD)
 			error(Eisdir);
-		c->mode = 0;
+		c->mode = OREAD;
 		c->flag |= COPEN;
 		c->offset = 0;
 		return c;
diff --git a/sys/src/kern/port/devproc.c b/sys/src/kern/port/devproc.c
index e6e64a9..53b86c7 100644
--- a/sys/src/kern/port/devproc.c
+++ b/sys/src/kern/port/devproc.c
@@ -25,6 +25,12 @@
 #include	<trace.h>
 #include	"ureg.h"
 
+extern long write_working_dir(Proc* p, void *va, long n, int64_t off);
+extern long read_working_dir(Proc* p, void *va, long n, int64_t off);
+
+/* We can have up to 32 files in proc/n sice we dedicate 5 bits in Qid
+ * to it (see QSHIFT)
+ */
 enum
 {
 	Qdir,
@@ -47,6 +53,7 @@ enum
 	Qwait,
 	Qprofile,
 	Qsyscall,
+	Qwdir,
 };
 
 enum
@@ -76,23 +83,25 @@ enum{
 };
 
 #define STATSIZE	(2*KNAMELEN+NUMSIZE+9*NUMSIZE + 1)
-/*
- * Status, fd, and ns are left fully readable (0444) because of their use in debugging,
- * particularly on shared servers.
- * Arguably, ns and fd shouldn't be readable; if you'd prefer, change them to 0000
+/* In Plan 9 status, fd, and ns were left fully readable (0444)
+ * because of their use in debugging, particularly on shared servers.
+ *
+ * In Jehanne the process owner and the host owner can read
+ * status and fd, but not others (0440).
+ * TODO: allow per process stats and permissions.
  */
 Dirtab procdir[] =
 {
 	"args",		{Qargs},	0,			0660,
 	"ctl",		{Qctl},		0,			0000,
-	"fd",		{Qfd},		0,			0444,
+	"fd",		{Qfd},		0,			0440,
 	"fpregs",	{Qfpregs},	0,			0000,
 	"kregs",	{Qkregs},	sizeof(Ureg),		0400,
 	"mem",		{Qmem},		0,			0000,
 	"note",		{Qnote},	0,			0000,
 	"noteid",	{Qnoteid},	0,			0664,
 	"notepg",	{Qnotepg},	0,			0000,
-	"ns",		{Qns},		0,			0444,
+	"ns",		{Qns},		0,			0440,
 	"proc",		{Qproc},	0,			0400,
 	"regs",		{Qregs},	sizeof(Ureg),		0000,
 	"segment",	{Qsegment},	0,			0444,
@@ -100,6 +109,7 @@ Dirtab procdir[] =
 	"text",		{Qtext},	0,			0000,
 	"wait",		{Qwait},	0,			0400,
 	"syscall",	{Qsyscall},	0,			0400,
+	"wdir",		{Qwdir},	0,			0640,
 };
 
 static
@@ -124,7 +134,7 @@ Cmdtab proccmd[] = {
 
 /*
  * Qids are, in path:
- *	 4 bits of file type (qids above)
+ *	 5 bits of file type (qids above)
  *	23 bits of process slot number + 1
  *	     in vers,
  *	32 bits of pid, for consistency checking
@@ -232,6 +242,14 @@ procgen(Chan *c, char *name, Dirtab *tab, int _1, int s, Dir *dp)
 		len = p->nwait;	/* incorrect size, but >0 means there's something to read */
 		break;
 	}
+	switch(QID(tab->qid)){
+	case Qwdir:
+		/* file length might be relevant to the caller to
+		 * malloc enough space in the buffer
+		 */
+		len = 1 + strlen(p->dot->path->s);
+		break;
+	}
 
 	mkqid(&qid, path|tab->qid.path, c->qid.vers, QTFILE);
 	devdir(c, qid, tab->name, len, p->user, perm, dp);
@@ -424,6 +442,17 @@ procopen(Chan *c, unsigned long omode)
 		c->pgrpid.vers = p->noteid;
 		break;
 
+	case Qwdir:
+		if(p == up)	/* self write is always allowed */
+			break;
+		if(omode > ORDWR)
+			error(Eperm);
+		if(strcmp(up->user, p->user) != 0	/* process owner can read/write */
+		|| !iseve()				/* host owner can read */
+		|| (omode&OWRITE) != 0)
+			error(Eperm);
+		break;
+
 	default:
 		poperror();
 		qunlock(&p->debug);
@@ -1058,6 +1087,10 @@ procread(Chan *c, void *va, long n, int64_t off)
 		r = procfds(p, va, n, offset);
 		psdecref(p);
 		return r;
+	case Qwdir:
+		r = read_working_dir(p, va, n, off);
+		psdecref(p);
+		return r;
 	}
 	error(Egreg);
 	return 0;			/* not reached */
@@ -1213,6 +1246,9 @@ procwrite(Chan *c, void *va, long n, int64_t off)
 		if(p->noteid != id)
 			error(Ebadarg);
 		break;
+	case Qwdir:
+		n = write_working_dir(p, va, n, off);
+		break;
 	default:
 		poperror();
 		qunlock(&p->debug);
diff --git a/sys/src/kern/port/devsegment.c b/sys/src/kern/port/devsegment.c
index 6ec55fc..1d53aef 100644
--- a/sys/src/kern/port/devsegment.c
+++ b/sys/src/kern/port/devsegment.c
@@ -215,7 +215,7 @@ segmentopen(Chan *c, int omode)
 	switch(TYPE(c)){
 	case Qtopdir:
 	case Qsegdir:
-		if(omode != 0)
+		if(omode != OREAD)
 			error(Eisdir);
 		break;
 	case Qctl:
diff --git a/sys/src/kern/port/devself.c b/sys/src/kern/port/devself.c
index 275f6ce..522d2f9 100644
--- a/sys/src/kern/port/devself.c
+++ b/sys/src/kern/port/devself.c
@@ -37,6 +37,7 @@ typedef enum SelfNodes
 	Qppid,
 	Qsegments,
 	Qpipes,
+	Qwdir,
 } SelfNodes;
 
 typedef enum SegmentsCmd
@@ -65,9 +66,49 @@ static Dirtab selfdir[]={
 	"ppid",		{Qppid},		0,		0,
 	"segments",	{Qsegments},		0,		0644,
 	"pipes",	{Qpipes},		0,		0,
+	"wdir",		{Qwdir},		0,		0644,
 };
 
 
+static int
+selfgen(Chan *c, char *name, Dirtab *tab, int ntab, int i, Dir *dp)
+{
+	long length;
+	if(tab == 0)
+		return -1;
+	if(i == DEVDOTDOT){
+		if(QID(c->qid) != Qdir)
+			panic("selfwalk %llux", c->qid.path);
+		devdir(c, selfdir[0].qid, "#0", 0, up->user, selfdir[0].perm, dp);
+		return 1;
+	}
+
+	if(name){
+		for(i=1; i<ntab; i++)
+			if(strcmp(tab[i].name, name) == 0)
+				break;
+		if(i==ntab)
+			return -1;
+		tab += i;
+	}else{
+		/* skip over the first element, that for . itself */
+		i++;
+		if(i >= ntab)
+			return -1;
+		tab += i;
+	}
+	if(tab->qid.path == Qwdir) {
+		/* file length might be relevant to the caller to
+		 * malloc enough space in the buffer
+		 */
+		length = 1 + strlen(up->dot->path->s);
+	} else {
+		length = tab->length;
+	}
+	devdir(c, tab->qid, tab->name, length, up->user, tab->perm, dp);
+	return 1;
+}
+
 static Chan*
 selfattach(Chan *c, Chan *ac, char *spec, int flags)
 {
@@ -77,23 +118,80 @@ selfattach(Chan *c, Chan *ac, char *spec, int flags)
 static Walkqid*
 selfwalk(Chan *c, Chan *nc, char **name, int nname)
 {
-	return devwalk(c, nc, name, nname, selfdir, nelem(selfdir), devgen);
+	return devwalk(c, nc, name, nname, selfdir, nelem(selfdir), selfgen);
 }
 
 static long
 selfstat(Chan *c, uint8_t *dp, long n)
 {
-	return devstat(c, dp, n, selfdir, nelem(selfdir), devgen);
+	return devstat(c, dp, n, selfdir, nelem(selfdir), selfgen);
 }
 
 static Chan*
 selfopen(Chan *c, unsigned long omode)
 {
 	c->aux = nil;
-	c = devopen(c, omode, selfdir, nelem(selfdir), devgen);
+	c = devopen(c, omode, selfdir, nelem(selfdir), selfgen);
 	return c;
 }
 
+long
+read_working_dir(Proc* p, void *va, long n, int64_t off)
+{
+	int i, j;
+	char *path;
+	Chan *dot;
+
+	dot = up->dot;
+	path = dot->path->s;
+	i = 1 + strlen(path);
+	if(va == nil){
+		/* the user is actually asking for the space */
+		if(off != 0 && off != ~0) {
+			/* #0/wdir does not allow offset in read */
+			error("offset reading wdir size");
+		}
+		errorl("not enough space in buffer", ~i);
+	}
+	if(off > i)
+		return 0;
+	j = i - off;
+	if(n < j)
+		j = n;
+	memmove(va, path, j);
+
+	return j;
+}
+
+
+long
+write_working_dir(Proc* p, void *va, long n, int64_t off)
+{
+	Chan *c, *dot;
+	char *path, *epath;
+
+	dot = p->dot;
+	path = va;
+	epath = vmemchr(path, 0, n);
+
+	if(n <= 0)
+		error(Ebadarg);
+	if(off != 0 && off != ~0)
+		error("offset writing wdir");
+	if(epath-path>=n)
+		error("no terminal zero writing wdir");
+
+	c = namec(path, Atodir, 0, 0);
+	if(CASV(&p->dot, dot, c)){
+		cclose(dot);
+	} else {
+		cclose(c);
+		error("race writing wdir");
+	}
+
+	return 0;
+}
+
 static long
 selfread(Chan *c, void *va, long n, int64_t off)
 {
@@ -104,6 +202,8 @@ selfread(Chan *c, void *va, long n, int64_t off)
 
 	offset = off;
 	switch(QID(c->qid)){
+	case Qdir:
+		return devdirread(c, va, n, selfdir, nelem(selfdir), selfgen);
 	case Qsegments:
 		rlock(&up->seglock);
 		j = 0;
@@ -127,6 +227,8 @@ selfread(Chan *c, void *va, long n, int64_t off)
 			exhausted("segments");
 		memmove(va, &statbuf[offset], n);
 		return n;
+	case Qwdir:
+		return read_working_dir(up, va, n, off);
 	default:
 		error(Egreg);
 	}
@@ -271,10 +373,10 @@ selfwrite(Chan *c, void *va, long n, int64_t off)
 	default:
 		error(Egreg);
 	case Qsegments:
-		n = procsegctl(up, va, n);
-		break;
+		return procsegctl(up, va, n);
+	case Qwdir:
+		return write_working_dir(up, va, n, off);
 	}
-	return n;
 }
 
 static int
diff --git a/sys/src/kern/port/devshr.c b/sys/src/kern/port/devshr.c
index 28e3e6d..a5950bf 100644
--- a/sys/src/kern/port/devshr.c
+++ b/sys/src/kern/port/devshr.c
@@ -1,21 +1,3 @@
-/*
- * This file is part of Jehanne.
- *
- * Copyright (C) 2015-2016 Giacomo Tesio <giacomo@tesio.it>
- *
- * Jehanne is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, version 2 of the License.
- *
- * Jehanne is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with Jehanne.  If not, see <http://www.gnu.org/licenses/>.
- */
-
 /* This device has been ported from 9front.
  */
 #include	"u.h"
diff --git a/sys/src/kern/port/fault.c b/sys/src/kern/port/fault.c
index 842d162..37c764b 100644
--- a/sys/src/kern/port/fault.c
+++ b/sys/src/kern/port/fault.c
@@ -6,13 +6,6 @@
 #include	"fns.h"
 #include	"../port/error.h"
 
-//char *faulttypes[] = {
-	//[FT_WRITE] "write",
-	//[FT_READ] "read",
-	//[FT_EXEC] "exec"
-//};
-
-
 int
 fault(uintptr_t addr, uintptr_t pc, int ftype)
 {
@@ -70,132 +63,6 @@ fault(uintptr_t addr, uintptr_t pc, int ftype)
 	return -1;
 }
 
-//int
-//fixfault(Segment *s, uintptr_t addr, int ftype, int dommuput)
-//{
-	//int type;
-	//Pte **p, *etp;
-	//uintptr_t soff;
-	//uintmem mmuphys;
-	//Page **pg, *old, *new;
-	//Page *(*fn)(Segment*, uintptr_t);
-	//uintptr_t pgsize;
-	//Pages *pages;
-
-	//pages = s->pages;	/* TO DO: segwalk */
-	//pgsize = 1<<pages->lg2pgsize;
-	//addr &= ~(pgsize-1);
-	//soff = addr-s->pages->base;
-
-	//p = &pages->map[soff/pages->ptemapmem];
-	//if(*p == nil)
-		//*p = ptealloc();
-
-	//etp = *p;
-	//pg = &etp->pages[(soff&(pages->ptemapmem-1))>>pages->lg2pgsize];
-
-	//if(pg < etp->first)
-		//etp->first = pg;
-	//if(pg > etp->last)
-		//etp->last = pg;
-
-	//type = s->type&SG_TYPE;
-	//if(*pg == nil){
-		//switch(type){
-		//case SG_BSS:			/* Zero fill on demand */
-		//case SG_SHARED:
-		//case SG_STACK:
-			//new = newpage(1, s->pages->lg2pgsize, &s->lk);
-			//if(new == nil)
-				//return -1;
-			//*pg = new;
-			//break;
-
-		//case SG_LOAD:
-		//case SG_TEXT:	/* demand load */
-		//case SG_DATA:
-			//if(!loadimagepage(s->image, s, pg, addr))
-				//return -1;
-			//break;
-
-		//case SG_PHYSICAL:
-			//fn = s->pseg->pgalloc;
-			//if(fn != nil)
-				//*pg = (*fn)(s, addr);
-			//else {
-				//new = smalloc(sizeof(Page));
-				//new->pa = s->pseg->pa+(addr-s->pages->base);
-				//new->r.ref = 1;
-				//new->lg2size = s->pseg->lg2pgsize;
-				//if(new->lg2size == 0)
-					//new->lg2size = PGSHFT;	/* TO DO */
-				//*pg = new;
-			//}
-			//break;
-		//default:
-			//panic("fault on demand");
-			//break;
-		//}
-	//}
-	//mmuphys = 0;
-	//switch(type) {
-	//default:
-		//panic("fault");
-		//break;
-
-	//case SG_TEXT:
-		//DBG("text pg %#p: %#p -> %#P %d\n", pg, addr, (*pg)->pa, (*pg)->r.ref);
-		//mmuphys = PPN((*pg)->pa) | PTERONLY|PTEVALID;
-		//break;
-
-	//case SG_BSS:
-	//case SG_SHARED:
-	//case SG_STACK:
-	//case SG_DATA:			/* copy on write */
-		//DBG("data pg %#p: %#p -> %#P %d\n", pg, addr, (*pg)->pa, (*pg)->r.ref);
-		///*
-		 //*  It's only possible to copy on write if
-		 //*  we're the only user of the segment.
-		 //*/
-		//if(ftype != FT_WRITE && sys->copymode == 0 && s->r.ref == 1) {
-			//mmuphys = PPN((*pg)->pa)|PTERONLY|PTEVALID;
-			//break;
-		//}
-
-		//old = *pg;
-		//if(old->r.ref > 1){
-			///* shared (including image pages): make private writable copy */
-			//new = newpage(0, s->pages->lg2pgsize, &s->lk);
-			//if(new != nil)
-				//copypage(old, new);
-			//*pg = new;
-			//putpage(old);
-			//if(new == nil)
-				//return -1;
-			//DBG("data' pg %#p: %#p -> %#P %d\n", *pg, addr, old->pa, old->r.ref);
-		//}else if(old->r.ref <= 0)
-			//panic("fault: page %#p %#P ref %d <= 0", old, old->pa, old->r.ref);
-		//mmuphys = PPN((*pg)->pa) | PTEWRITE | PTEVALID;
-		//break;
-
-	//case SG_PHYSICAL:
-		//mmuphys = PPN((*pg)->pa) | PTEVALID;
-		//if((s->pseg->attr & SG_WRITE))
-			//mmuphys |= PTEWRITE;
-		//if((s->pseg->attr & SG_CACHED) == 0)
-			//mmuphys |= PTEUNCACHED;
-		//break;
-	//}
-	//runlock(&s->lk);
-
-	//if(dommuput)
-		//mmuput(addr, mmuphys, *pg);
-	//if(ftype == FT_EXEC)
-		//peekAtExecFaults(addr);
-
-	//return 0;
-//}
-
 /*
  * Called only in a system call
  */
@@ -225,7 +92,7 @@ void*
 validaddr(void* addr, long len, int write)
 {
 	if(!okaddr(PTR2UINT(addr), len, write)){
-		pprint("trap: invalid address %#p/%lud in sys call pc=%#P\n", addr, len, userpc(nil));
+		pprint("trap: invalid address %#p/%ld in sys call pc=%#P\n", addr, len, userpc(nil));
 		postnote(up, 1, "sys: bad address in syscall", NDebug);
 		error(Ebadarg);
 	}
diff --git a/sys/src/kern/port/sysfile.c b/sys/src/kern/port/sysfile.c
index cc22a91..ea38c53 100644
--- a/sys/src/kern/port/sysfile.c
+++ b/sys/src/kern/port/sysfile.c
@@ -597,14 +597,24 @@ mountfix(Chan *c, uint8_t *op, int32_t n, int32_t maxn)
 }
 
 long
-syspread(int fd, void *p, int32_t n, int64_t off)
+syspread(int fd, void *p, long n, int64_t off)
 {
 	int32_t nn;
 	long nnn;
 	int sequential;
 	Chan *c;
 
-	p = validaddr(p, n, 1);
+	if(n >= 0)
+		p = validaddr(p, n, 1);
+	else if(p != nil) {
+		/* in Jehanne, a negative length can be meaningful to
+		 * the target device/server, but with a negative length
+		 * to read the buffer must be nil
+		 */
+		pprint("trap: invalid address %#p/%ld in sys call pc=%#P\n", p, n, userpc(nil));
+		postnote(up, 1, "sys: bad address in syscall", NDebug);
+		error(Ebadarg);
+	}
 
 	c = fdtochan(fd, OREAD, 1, 1);
 
@@ -679,7 +689,7 @@ syspread(int fd, void *p, int32_t n, int64_t off)
 }
 
 long
-syspwrite(int fd, void *p, int32_t n, int64_t off)
+syspwrite(int fd, void *p, long n, int64_t off)
 {
 	long r;
 	int sequential;
@@ -858,20 +868,6 @@ sysfstat(int fd, uint8_t* p, int n)
 	return r;
 }
 
-int
-syschdir(char *aname)
-{
-	Chan *c;
-
-	aname = validaddr(aname, 1, 0);
-
-	c = namec(aname, Atodir, 0, 0);
-	cclose(up->dot);
-	up->dot = c;
-
-	return 0;
-}
-
 /* white list of devices we allow mounting on.
  * At some point we can have build generate this if we ever
  * really start using it.
diff --git a/sys/src/lib/auth/newns.c b/sys/src/lib/auth/newns.c
index 8d7ac32..ea37b3b 100644
--- a/sys/src/lib/auth/newns.c
+++ b/sys/src/lib/auth/newns.c
@@ -77,7 +77,7 @@ buildns(int newns, char *user, char *file)
 	/* make sure we managed to cd into the new name space */
 	if(newns && !cdroot){
 		path = malloc(1024);
-		if(path == nil || getwd(path, 1024) == 0 || chdir(path) < 0)
+		if(path == nil || getwd(path, 1024) <= 0 || chdir(path) < 0)
 			chdir("/");
 		if(path != nil)
 			free(path);
@@ -222,7 +222,7 @@ unquote(char *s)
 {
 	char *r, *w;
 	int inquote;
-	
+
 	inquote = 0;
 	for(r=w=s; *r; r++){
 		if(*r != '\''){
@@ -267,7 +267,7 @@ nextdollar(char *arg)
 {
 	char *p;
 	int inquote;
-	
+
 	inquote = 0;
 	for(p=arg; *p; p++){
 		if(*p == '\'')
diff --git a/sys/src/lib/c/9sys/chdir.c b/sys/src/lib/c/9sys/chdir.c
new file mode 100644
index 0000000..8c7009c
--- /dev/null
+++ b/sys/src/lib/c/9sys/chdir.c
@@ -0,0 +1,38 @@
+/*
+ * This file is part of Jehanne.
+ *
+ * Copyright (C) 2016 Giacomo Tesio <giacomo@tesio.it>
+ *
+ * Jehanne is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2 of the License.
+ *
+ * Jehanne is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Jehanne.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <u.h>
+#include <libc.h>
+
+int
+chdir(const char *dirname)
+{
+	char buf[32];
+	int tmp, fd;
+
+	tmp = getpid();
+	snprint(buf, sizeof(buf), "/proc/%d/wdir", tmp);
+	fd = open(buf, OWRITE);
+	if(fd < 0)
+		fd = open("#0/wdir", OWRITE);
+	if(fd < 0)
+		return fd;
+	tmp = write(fd, dirname, 1+strlen(dirname));
+	close(fd);
+	return tmp;
+}
diff --git a/sys/src/lib/c/9sys/getwd.c b/sys/src/lib/c/9sys/getwd.c
index 4834c1e..2b4e04b 100644
--- a/sys/src/lib/c/9sys/getwd.c
+++ b/sys/src/lib/c/9sys/getwd.c
@@ -1,26 +1,45 @@
 /*
- * This file is part of the UCB release of Plan 9. It is subject to the license
- * terms in the LICENSE file found in the top-level directory of this
- * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No
- * part of the UCB release of Plan 9, including this file, may be copied,
- * modified, propagated, or distributed except according to the terms contained
- * in the LICENSE file.
+ * This file is part of Jehanne.
+ *
+ * Copyright (C) 2016 Giacomo Tesio <giacomo@tesio.it>
+ *
+ * Jehanne is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2 of the License.
+ *
+ * Jehanne is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Jehanne.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #include <u.h>
 #include <libc.h>
 
-char*
+/* Fills buf with the current workking directory.
+ *
+ * Returns
+ * - 0 on error
+ * - the negated length of the working directory path if nbuf is too small
+ * - the (positive) length of the working directory on success
+ */
+long
 getwd(char *buf, int nbuf)
 {
-	int n, fd;
+	long n;
+	int fd;
 
-	fd = open(".", OREAD);
+	fd = open("#0/wdir", OREAD);
 	if(fd < 0)
-		return nil;
-	n = fd2path(fd, buf, nbuf);
+		return 0;
+	n = read(fd, nil, -1);
+	if(n == ~0)	/* an error occurred */
+		return 0;
+	if(nbuf >= ~n)
+		n = read(fd, buf, nbuf);
 	close(fd);
-	if(n < 0)
-		return nil;
-	return buf;
+	return n;
 }
diff --git a/sys/src/lib/c/build.json b/sys/src/lib/c/build.json
index 097b7a5..6de15f9 100644
--- a/sys/src/lib/c/build.json
+++ b/sys/src/lib/c/build.json
@@ -38,6 +38,7 @@
 			"9sys/access.c",
 			"9sys/announce.c",
 			"9sys/awakened.c",
+			"9sys/chdir.c",
 			"9sys/convD2M.c",
 			"9sys/convM2D.c",
 			"9sys/cputime.c",
diff --git a/sys/src/sysconf.json b/sys/src/sysconf.json
index 853cc64..ab80fe9 100644
--- a/sys/src/sysconf.json
+++ b/sys/src/sysconf.json
@@ -65,19 +65,9 @@
 		},
 		{
 			"Args": [
-				"const char*"
+				"int"
 			],
 			"Id": 4,
-			"Name": "chdir",
-			"Ret": [
-				"int"
-			]
-		},
-		{
-			"Args": [
-				"int"
-			],
-			"Id": 5,
 			"Name": "close",
 			"Ret": [
 				"long"
@@ -89,7 +79,7 @@
 				"uint32_t",
 				"uint32_t"
 			],
-			"Id": 6,
+			"Id": 5,
 			"Name": "create",
 			"Ret": [
 				"long"
@@ -100,7 +90,7 @@
 				"int32_t",
 				"int32_t"
 			],
-			"Id": 7,
+			"Id": 6,
 			"Name": "dup",
 			"Ret": [
 				"int32_t"
@@ -111,7 +101,7 @@
 				"char*",
 				"int"
 			],
-			"Id": 8,
+			"Id": 7,
 			"Name": "errstr",
 			"Ret": [
 				"int"
@@ -122,7 +112,7 @@
 				"const char*",
 				"const char**"
 			],
-			"Id": 9,
+			"Id": 8,
 			"Name": "exec",
 			"Ret": [
 				"uintptr_t"
@@ -132,7 +122,7 @@
 			"Args": [
 				"const char*"
 			],
-			"Id": 10,
+			"Id": 9,
 			"Name": "_exits",
 			"Ret": [
 				"int"
@@ -143,7 +133,7 @@
 				"int",
 				"const char*"
 			],
-			"Id": 11,
+			"Id": 10,
 			"Name": "fauth",
 			"Ret": [
 				"int"
@@ -155,7 +145,7 @@
 				"const char*",
 				"uint32_t"
 			],
-			"Id": 12,
+			"Id": 11,
 			"Name": "fd2path",
 			"Ret": [
 				"int32_t"
@@ -167,7 +157,7 @@
 				"uint8_t*",
 				"int"
 			],
-			"Id": 13,
+			"Id": 12,
 			"Name": "fstat",
 			"Ret": [
 				"long"
@@ -180,7 +170,7 @@
 				"const char*",
 				"int"
 			],
-			"Id": 14,
+			"Id": 13,
 			"Name": "fversion",
 			"Ret": [
 				"int"
@@ -192,7 +182,7 @@
 				"const uint8_t*",
 				"uint32_t"
 			],
-			"Id": 15,
+			"Id": 14,
 			"Name": "fwstat",
 			"Ret": [
 				"long"
@@ -207,7 +197,7 @@
 				"const char*",
 				"int"
 			],
-			"Id": 16,
+			"Id": 15,
 			"Name": "mount",
 			"Ret": [
 				"int"
@@ -217,7 +207,7 @@
 			"Args": [
 				"int"
 			],
-			"Id": 17,
+			"Id": 16,
 			"Name": "noted",
 			"Ret": [
 				"int"
@@ -227,14 +217,14 @@
 			"Args": [
 				"const void*"
 			],
-			"Id": 18,
+			"Id": 17,
 			"Name": "notify",
 			"Ret": [
 				"int"
 			]
 		},
 		{
-			"Id": 19,
+			"Id": 18,
 			"Name": "nsec",
 			"Ret": [
 				"long"
@@ -245,7 +235,7 @@
 				"const char*",
 				"uint32_t"
 			],
-			"Id": 20,
+			"Id": 19,
 			"Name": "open",
 			"Ret": [
 				"long"
@@ -255,10 +245,10 @@
 			"Args": [
 				"int",
 				"void*",
-				"int",
+				"long",
 				"long"
 			],
-			"Id": 21,
+			"Id": 20,
 			"Name": "pread",
 			"Ret": [
 				"long"
@@ -268,10 +258,10 @@
 			"Args": [
 				"int",
 				"const void*",
-				"int",
+				"long",
 				"long"
 			],
-			"Id": 22,
+			"Id": 21,
 			"Name": "pwrite",
 			"Ret": [
 				"long"
@@ -281,7 +271,7 @@
 			"Args": [
 				"const char*"
 			],
-			"Id": 23,
+			"Id": 22,
 			"Name": "remove",
 			"Ret": [
 				"long"
@@ -292,7 +282,7 @@
 				"const void*",
 				"void*"
 			],
-			"Id": 24,
+			"Id": 23,
 			"Name": "rendezvous",
 			"Ret": [
 				"void*"
@@ -302,7 +292,7 @@
 			"Args": [
 				"uint32_t"
 			],
-			"Id": 25,
+			"Id": 24,
 			"Name": "rfork",
 			"Ret": [
 				"int"
@@ -314,7 +304,7 @@
 				"long",
 				"int"
 			],
-			"Id": 26,
+			"Id": 25,
 			"Name": "seek",
 			"Ret": [
 				"long"
@@ -325,7 +315,7 @@
 				"int*",
 				"int"
 			],
-			"Id": 27,
+			"Id": 26,
 			"Name": "semacquire",
 			"Ret": [
 				"int"
@@ -336,7 +326,7 @@
 				"int*",
 				"int"
 			],
-			"Id": 28,
+			"Id": 27,
 			"Name": "semrelease",
 			"Ret": [
 				"int"
@@ -347,7 +337,7 @@
 				"int*",
 				"uint64_t"
 			],
-			"Id": 29,
+			"Id": 28,
 			"Name": "tsemacquire",
 			"Ret": [
 				"int"
@@ -358,7 +348,7 @@
 				"const char*",
 				"const char*"
 			],
-			"Id": 30,
+			"Id": 29,
 			"Name": "unmount",
 			"Ret": [
 				"int"
@@ -368,7 +358,7 @@
 			"Args": [
 				"unsigned long"
 			],
-			"Id": 31,
+			"Id": 30,
 			"Name": "alarm",
 			"Ret": [
 				"long"