Import sources from 2011-03-30 iso image

1 files changed, 1110 insertions, 0 deletions

diff --git a/sys/src/cmd/ssh/sshnet.c b/sys/src/cmd/ssh/sshnet.c
new file mode 100755
index 000000000..1de834c72
--- /dev/null
+++ b/sys/src/cmd/ssh/sshnet.c
@@ -0,0 +1,1110 @@
+/*
+ * SSH network file system.
+ * Presents remote TCP stack as /net-style file system.
+ */
+
+#include "ssh.h"
+#include <bio.h>
+#include <ndb.h>
+#include <thread.h>
+#include <fcall.h>
+#include <9p.h>
+
+int rawhack = 1;
+Conn *conn;
+char *remoteip	= "<remote>";
+char *mtpt;
+
+Cipher *allcipher[] = {
+	&cipherrc4,
+	&cipherblowfish,
+	&cipher3des,
+	&cipherdes,
+	&ciphernone,
+	&ciphertwiddle,
+};
+
+Auth *allauth[] = {
+	&authpassword,
+	&authrsa,
+	&authtis,
+};
+
+char *cipherlist = "rc4 3des";
+char *authlist = "rsa password tis";
+
+Cipher*
+findcipher(char *name, Cipher **list, int nlist)
+{
+	int i;
+
+	for(i=0; i<nlist; i++)
+		if(strcmp(name, list[i]->name) == 0)
+			return list[i];
+	error("unknown cipher %s", name);
+	return nil;
+}
+
+Auth*
+findauth(char *name, Auth **list, int nlist)
+{
+	int i;
+
+	for(i=0; i<nlist; i++)
+		if(strcmp(name, list[i]->name) == 0)
+			return list[i];
+	error("unknown auth %s", name);
+	return nil;
+}
+
+void
+usage(void)
+{
+	fprint(2, "usage: sshnet [-A authlist] [-c cipherlist] [-m mtpt] [user@]hostname\n");
+	exits("usage");
+}
+
+int
+isatty(int fd)
+{
+	char buf[64];
+
+	buf[0] = '\0';
+	fd2path(fd, buf, sizeof buf);
+	if(strlen(buf)>=9 && strcmp(buf+strlen(buf)-9, "/dev/cons")==0)
+		return 1;
+	return 0;
+}
+
+enum
+{
+	Qroot,
+	Qcs,
+	Qtcp,
+	Qclone,
+	Qn,
+	Qctl,
+	Qdata,
+	Qlocal,
+	Qremote,
+	Qstatus,
+};
+
+#define PATH(type, n)		((type)|((n)<<8))
+#define TYPE(path)			((int)(path) & 0xFF)
+#define NUM(path)			((uint)(path)>>8)
+
+Channel *sshmsgchan;		/* chan(Msg*) */
+Channel *fsreqchan;			/* chan(Req*) */
+Channel *fsreqwaitchan;		/* chan(nil) */
+Channel *fsclunkchan;		/* chan(Fid*) */
+Channel *fsclunkwaitchan;	/* chan(nil) */
+ulong time0;
+
+enum
+{
+	Closed,
+	Dialing,
+	Established,
+	Teardown,
+};
+
+char *statestr[] = {
+	"Closed",
+	"Dialing",
+	"Established",
+	"Teardown",
+};
+
+typedef struct Client Client;
+struct Client
+{
+	int ref;
+	int state;
+	int num;
+	int servernum;
+	char *connect;
+	Req *rq;
+	Req **erq;
+	Msg *mq;
+	Msg **emq;
+};
+
+int nclient;
+Client **client;
+
+int
+newclient(void)
+{
+	int i;
+	Client *c;
+
+	for(i=0; i<nclient; i++)
+		if(client[i]->ref==0 && client[i]->state == Closed)
+			return i;
+
+	if(nclient%16 == 0)
+		client = erealloc9p(client, (nclient+16)*sizeof(client[0]));
+
+	c = emalloc9p(sizeof(Client));
+	memset(c, 0, sizeof(*c));
+	c->num = nclient;
+	client[nclient++] = c;
+	return c->num;
+}
+
+void
+queuereq(Client *c, Req *r)
+{
+	if(c->rq==nil)
+		c->erq = &c->rq;
+	*c->erq = r;
+	r->aux = nil;
+	c->erq = (Req**)&r->aux;
+}
+
+void
+queuemsg(Client *c, Msg *m)
+{
+	if(c->mq==nil)
+		c->emq = &c->mq;
+	*c->emq = m;
+	m->link = nil;
+	c->emq = (Msg**)&m->link;
+}
+
+void
+matchmsgs(Client *c)
+{
+	Req *r;
+	Msg *m;
+	int n, rm;
+
+	while(c->rq && c->mq){
+		r = c->rq;
+		c->rq = r->aux;
+
+		rm = 0;
+		m = c->mq;
+		n = r->ifcall.count;
+		if(n >= m->ep - m->rp){
+			n = m->ep - m->rp;
+			c->mq = m->link;
+			rm = 1;
+		}
+		memmove(r->ofcall.data, m->rp, n);
+		if(rm)
+			free(m);
+		else
+			m->rp += n;
+		r->ofcall.count = n;
+		respond(r, nil);
+	}
+}
+
+Req*
+findreq(Client *c, Req *r)
+{
+	Req **l;
+
+	for(l=&c->rq; *l; l=(Req**)&(*l)->aux){
+		if(*l == r){
+			*l = r->aux;
+			if(*l == nil)
+				c->erq = l;
+			return r;
+		}
+	}
+	return nil;
+}
+
+void
+dialedclient(Client *c)
+{
+	Req *r;
+
+	if(r=c->rq){
+		if(r->aux != nil)
+			sysfatal("more than one outstanding dial request (BUG)");
+		if(c->state == Established)
+			respond(r, nil);
+		else
+			respond(r, "connect failed");
+	}
+	c->rq = nil;
+}
+
+void
+teardownclient(Client *c)
+{
+	Msg *m;
+
+	c->state = Teardown;
+	m = allocmsg(conn, SSH_MSG_CHANNEL_INPUT_EOF, 4);
+	putlong(m, c->servernum);
+	sendmsg(m);
+}
+
+void
+hangupclient(Client *c)
+{
+	Req *r, *next;
+	Msg *m, *mnext;
+
+	c->state = Closed;
+	for(m=c->mq; m; m=mnext){
+		mnext = m->link;
+		free(m);
+	}
+	c->mq = nil;
+	for(r=c->rq; r; r=next){
+		next = r->aux;
+		respond(r, "hangup on network connection");
+	}
+	c->rq = nil;
+}
+
+void
+closeclient(Client *c)
+{
+	Msg *m, *next;
+
+	if(--c->ref)
+		return;
+
+	if(c->rq != nil)
+		sysfatal("ref count reached zero with requests pending (BUG)");
+
+	for(m=c->mq; m; m=next){
+		next = m->link;
+		free(m);
+	}
+	c->mq = nil;
+
+	if(c->state != Closed)
+		teardownclient(c);
+}
+
+	
+void
+sshreadproc(void *a)
+{
+	Conn *c;
+	Msg *m;
+
+	c = a;
+	for(;;){
+		m = recvmsg(c, -1);
+		if(m == nil)
+			sysfatal("eof on ssh connection");
+		sendp(sshmsgchan, m);
+	}
+}
+
+typedef struct Tab Tab;
+struct Tab
+{
+	char *name;
+	ulong mode;
+};
+
+Tab tab[] =
+{
+	"/",		DMDIR|0555,
+	"cs",		0666,
+	"tcp",	DMDIR|0555,	
+	"clone",	0666,
+	nil,		DMDIR|0555,
+	"ctl",		0666,
+	"data",	0666,
+	"local",	0444,
+	"remote",	0444,
+	"status",	0444,
+};
+
+static void
+fillstat(Dir *d, uvlong path)
+{
+	Tab *t;
+
+	memset(d, 0, sizeof(*d));
+	d->uid = estrdup9p("ssh");
+	d->gid = estrdup9p("ssh");
+	d->qid.path = path;
+	d->atime = d->mtime = time0;
+	t = &tab[TYPE(path)];
+	if(t->name)
+		d->name = estrdup9p(t->name);
+	else{
+		d->name = smprint("%ud", NUM(path));
+		if(d->name == nil)
+			sysfatal("out of memory");
+	}
+	d->qid.type = t->mode>>24;
+	d->mode = t->mode;
+}
+
+static void
+fsattach(Req *r)
+{
+	if(r->ifcall.aname && r->ifcall.aname[0]){
+		respond(r, "invalid attach specifier");
+		return;
+	}
+	r->fid->qid.path = PATH(Qroot, 0);
+	r->fid->qid.type = QTDIR;
+	r->fid->qid.vers = 0;
+	r->ofcall.qid = r->fid->qid;
+	respond(r, nil);
+}
+
+static void
+fsstat(Req *r)
+{
+	fillstat(&r->d, r->fid->qid.path);
+	respond(r, nil);
+}
+
+static int
+rootgen(int i, Dir *d, void*)
+{
+	i += Qroot+1;
+	if(i <= Qtcp){
+		fillstat(d, i);
+		return 0;
+	}
+	return -1;
+}
+
+static int
+tcpgen(int i, Dir *d, void*)
+{
+	i += Qtcp+1;
+	if(i < Qn){
+		fillstat(d, i);
+		return 0;
+	}
+	i -= Qn;
+	if(i < nclient){
+		fillstat(d, PATH(Qn, i));
+		return 0;
+	}
+	return -1;
+}
+
+static int
+clientgen(int i, Dir *d, void *aux)
+{
+	Client *c;
+
+	c = aux;
+	i += Qn+1;
+	if(i <= Qstatus){
+		fillstat(d, PATH(i, c->num));
+		return 0;
+	}
+	return -1;
+}
+
+static char*
+fswalk1(Fid *fid, char *name, Qid *qid)
+{
+	int i, n;
+	char buf[32];
+	ulong path;
+
+	path = fid->qid.path;
+	if(!(fid->qid.type&QTDIR))
+		return "walk in non-directory";
+
+	if(strcmp(name, "..") == 0){
+		switch(TYPE(path)){
+		case Qn:
+			qid->path = PATH(Qtcp, NUM(path));
+			qid->type = tab[Qtcp].mode>>24;
+			return nil;
+		case Qtcp:
+			qid->path = PATH(Qroot, 0);
+			qid->type = tab[Qroot].mode>>24;
+			return nil;
+		case Qroot:
+			return nil;
+		default:
+			return "bug in fswalk1";
+		}
+	}
+
+	i = TYPE(path)+1;
+	for(; i<nelem(tab); i++){
+		if(i==Qn){
+			n = atoi(name);
+			snprint(buf, sizeof buf, "%d", n);
+			if(n < nclient && strcmp(buf, name) == 0){
+				qid->path = PATH(i, n);
+				qid->type = tab[i].mode>>24;
+				return nil;
+			}
+			break;
+		}
+		if(strcmp(name, tab[i].name) == 0){
+			qid->path = PATH(i, NUM(path));
+			qid->type = tab[i].mode>>24;
+			return nil;
+		}
+		if(tab[i].mode&DMDIR)
+			break;
+	}
+	return "directory entry not found";
+}
+
+typedef struct Cs Cs;
+struct Cs
+{
+	char *resp;
+	int isnew;
+};
+
+static int
+ndbfindport(char *p)
+{
+	char *s, *port;
+	int n;
+	static Ndb *db;
+
+	if(*p == '\0')
+		return -1;
+
+	n = strtol(p, &s, 0);
+	if(*s == '\0')
+		return n;
+
+	if(db == nil){
+		db = ndbopen("/lib/ndb/common");
+		if(db == nil)
+			return -1;
+	}
+
+	port = ndbgetvalue(db, nil, "tcp", p, "port", nil);
+	if(port == nil)
+		return -1;
+	n = atoi(port);
+	free(port);
+
+	return n;
+}	
+
+static void
+csread(Req *r)
+{
+	Cs *cs;
+
+	cs = r->fid->aux;
+	if(cs->resp==nil){
+		respond(r, "cs read without write");
+		return;
+	}
+	if(r->ifcall.offset==0){
+		if(!cs->isnew){
+			r->ofcall.count = 0;
+			respond(r, nil);
+			return;
+		}
+		cs->isnew = 0;
+	}
+	readstr(r, cs->resp);
+	respond(r, nil);
+}
+
+static void
+cswrite(Req *r)
+{
+	int port, nf;
+	char err[ERRMAX], *f[4], *s, *ns;
+	Cs *cs;
+
+	cs = r->fid->aux;
+	s = emalloc(r->ifcall.count+1);
+	memmove(s, r->ifcall.data, r->ifcall.count);
+	s[r->ifcall.count] = '\0';
+
+	nf = getfields(s, f, nelem(f), 0, "!");
+	if(nf != 3){
+		free(s);
+		respond(r, "can't translate");
+		return;
+	}
+	if(strcmp(f[0], "tcp") != 0 && strcmp(f[0], "net") != 0){
+		free(s);
+		respond(r, "unknown protocol");
+		return;
+	}
+	port = ndbfindport(f[2]);
+	if(port <= 0){
+		free(s);
+		respond(r, "no translation found");
+		return;
+	}
+
+	ns = smprint("%s/tcp/clone %s!%d", mtpt, f[1], port);
+	if(ns == nil){
+		free(s);
+		rerrstr(err, sizeof err);
+		respond(r, err);
+		return;
+	}
+	free(s);
+	free(cs->resp);
+	cs->resp = ns;
+	cs->isnew = 1;
+	r->ofcall.count = r->ifcall.count;
+	respond(r, nil);
+}
+
+static void
+ctlread(Req *r, Client *c)
+{
+	char buf[32];
+
+	sprint(buf, "%d", c->num);
+	readstr(r, buf);
+	respond(r, nil);
+}
+
+static void
+ctlwrite(Req *r, Client *c)
+{
+	char *f[3], *s;
+	int nf;
+	Msg *m;
+
+	s = emalloc(r->ifcall.count+1);
+	memmove(s, r->ifcall.data, r->ifcall.count);
+	s[r->ifcall.count] = '\0';
+
+	nf = tokenize(s, f, 3);
+	if(nf == 0){
+		free(s);
+		respond(r, nil);
+		return;
+	}
+
+	if(strcmp(f[0], "hangup") == 0){
+		if(c->state != Established)
+			goto Badarg;
+		if(nf != 1)
+			goto Badarg;
+		queuereq(c, r);
+		teardownclient(c);
+	}else if(strcmp(f[0], "connect") == 0){
+		if(c->state != Closed)
+			goto Badarg;
+		if(nf != 2)
+			goto Badarg;
+		c->connect = estrdup9p(f[1]);
+		nf = getfields(f[1], f, nelem(f), 0, "!");
+		if(nf != 2){
+			free(c->connect);
+			c->connect = nil;
+			goto Badarg;
+		}
+		c->state = Dialing;
+		m = allocmsg(conn, SSH_MSG_PORT_OPEN, 4+4+strlen(f[0])+4+4+strlen("localhost"));
+		putlong(m, c->num);
+		putstring(m, f[0]);
+		putlong(m, ndbfindport(f[1]));
+		putstring(m, "localhost");
+		queuereq(c, r);
+		sendmsg(m);
+	}else{
+	Badarg:
+		respond(r, "bad or inappropriate tcp control message");
+	}
+	free(s);
+}
+
+static void
+dataread(Req *r, Client *c)
+{
+	if(c->state != Established){
+		respond(r, "not connected");
+		return;
+	}
+	queuereq(c, r);
+	matchmsgs(c);
+}
+
+static void
+datawrite(Req *r, Client *c)
+{
+	Msg *m;
+
+	if(c->state != Established){
+		respond(r, "not connected");
+		return;
+	}
+	if(r->ifcall.count){
+		m = allocmsg(conn, SSH_MSG_CHANNEL_DATA, 4+4+r->ifcall.count);
+		putlong(m, c->servernum);
+		putlong(m, r->ifcall.count);
+		putbytes(m, r->ifcall.data, r->ifcall.count);
+		sendmsg(m);
+	}
+	r->ofcall.count = r->ifcall.count;
+	respond(r, nil);
+}
+
+static void
+localread(Req *r)
+{
+	char buf[128];
+
+	snprint(buf, sizeof buf, "%s!%d\n", remoteip, 0);
+	readstr(r, buf);
+	respond(r, nil);
+}
+
+static void
+remoteread(Req *r, Client *c)
+{
+	char *s;
+	char buf[128];
+
+	s = c->connect;
+	if(s == nil)
+		s = "::!0";
+	snprint(buf, sizeof buf, "%s\n", s);
+	readstr(r, buf);
+	respond(r, nil);
+}
+
+static void
+statusread(Req *r, Client *c)
+{
+	char buf[64];
+	char *s;
+
+	snprint(buf, sizeof buf, "%s!%d", remoteip, 0);
+	s = statestr[c->state];
+	readstr(r, s);
+	respond(r, nil);
+}
+
+static void
+fsread(Req *r)
+{
+	char e[ERRMAX];
+	ulong path;
+
+	path = r->fid->qid.path;
+	switch(TYPE(path)){
+	default:
+		snprint(e, sizeof e, "bug in fsread path=%lux", path);
+		respond(r, e);
+		break;
+
+	case Qroot:
+		dirread9p(r, rootgen, nil);
+		respond(r, nil);
+		break;
+
+	case Qcs:
+		csread(r);
+		break;
+
+	case Qtcp:
+		dirread9p(r, tcpgen, nil);
+		respond(r, nil);
+		break;
+
+	case Qn:
+		dirread9p(r, clientgen, client[NUM(path)]);
+		respond(r, nil);
+		break;
+
+	case Qctl:
+		ctlread(r, client[NUM(path)]);
+		break;
+
+	case Qdata:
+		dataread(r, client[NUM(path)]);
+		break;
+
+	case Qlocal:
+		localread(r);
+		break;
+
+	case Qremote:
+		remoteread(r, client[NUM(path)]);
+		break;
+
+	case Qstatus:
+		statusread(r, client[NUM(path)]);
+		break;
+	}
+}
+
+static void
+fswrite(Req *r)
+{
+	ulong path;
+	char e[ERRMAX];
+
+	path = r->fid->qid.path;
+	switch(TYPE(path)){
+	default:
+		snprint(e, sizeof e, "bug in fswrite path=%lux", path);
+		respond(r, e);
+		break;
+
+	case Qcs:
+		cswrite(r);
+		break;
+
+	case Qctl:
+		ctlwrite(r, client[NUM(path)]);
+		break;
+
+	case Qdata:
+		datawrite(r, client[NUM(path)]);
+		break;
+	}
+}
+
+static void
+fsopen(Req *r)
+{
+	static int need[4] = { 4, 2, 6, 1 };
+	ulong path;
+	int n;
+	Tab *t;
+	Cs *cs;
+
+	/*
+	 * lib9p already handles the blatantly obvious.
+	 * we just have to enforce the permissions we have set.
+	 */
+	path = r->fid->qid.path;
+	t = &tab[TYPE(path)];
+	n = need[r->ifcall.mode&3];
+	if((n&t->mode) != n){
+		respond(r, "permission denied");
+		return;
+	}
+
+	switch(TYPE(path)){
+	case Qcs:
+		cs = emalloc(sizeof(Cs));
+		r->fid->aux = cs;
+		respond(r, nil);
+		break;
+	case Qclone:
+		n = newclient();
+		path = PATH(Qctl, n);
+		r->fid->qid.path = path;
+		r->ofcall.qid.path = path;
+		if(chatty9p)
+			fprint(2, "open clone => path=%lux\n", path);
+		t = &tab[Qctl];
+		/* fall through */
+	default:
+		if(t-tab >= Qn)
+			client[NUM(path)]->ref++;
+		respond(r, nil);
+		break;
+	}
+}
+
+static void
+fsflush(Req *r)
+{
+	int i;
+
+	for(i=0; i<nclient; i++)
+		if(findreq(client[i], r->oldreq))
+			respond(r->oldreq, "interrupted");
+	respond(r, nil);
+}
+
+static void
+handlemsg(Msg *m)
+{
+	int chan, n;
+	Client *c;
+
+	switch(m->type){
+	case SSH_MSG_DISCONNECT:
+	case SSH_CMSG_EXIT_CONFIRMATION:
+		sysfatal("disconnect");
+
+	case SSH_CMSG_STDIN_DATA:
+	case SSH_CMSG_EOF:
+	case SSH_CMSG_WINDOW_SIZE:
+		/* don't care */
+		free(m);
+		break;
+
+	case SSH_MSG_CHANNEL_DATA:
+		chan = getlong(m);
+		n = getlong(m);
+		if(m->rp+n != m->ep)
+			sysfatal("got bad channel data");
+		if(chan<nclient && (c=client[chan])->state==Established){
+			queuemsg(c, m);
+			matchmsgs(c);
+		}else
+			free(m);
+		break;
+
+	case SSH_MSG_CHANNEL_INPUT_EOF:
+		chan = getlong(m);
+		free(m);
+		if(chan<nclient){
+			c = client[chan];
+			chan = c->servernum;
+			hangupclient(c);
+			m = allocmsg(conn, SSH_MSG_CHANNEL_OUTPUT_CLOSED, 4);
+			putlong(m, chan);
+			sendmsg(m);
+		}
+		break;
+
+	case SSH_MSG_CHANNEL_OUTPUT_CLOSED:
+		chan = getlong(m);
+		if(chan<nclient)
+			hangupclient(client[chan]);
+		free(m);
+		break;
+
+	case SSH_MSG_CHANNEL_OPEN_CONFIRMATION:
+		chan = getlong(m);
+		c = nil;
+		if(chan>=nclient || (c=client[chan])->state != Dialing){
+			if(c)
+				fprint(2, "cstate %d\n", c->state);
+			sysfatal("got unexpected open confirmation for %d", chan);
+		}
+		c->servernum = getlong(m);
+		c->state = Established;
+		dialedclient(c);
+		free(m);
+		break;
+
+	case SSH_MSG_CHANNEL_OPEN_FAILURE:
+		chan = getlong(m);
+		c = nil;
+		if(chan>=nclient || (c=client[chan])->state != Dialing)
+			sysfatal("got unexpected open failure");
+		if(m->rp+4 <= m->ep)
+			c->servernum = getlong(m);
+		c->state = Closed;
+		dialedclient(c);
+		free(m);
+		break;
+	}
+}
+
+void
+fsnetproc(void*)
+{
+	ulong path;
+	Alt a[4];
+	Cs *cs;
+	Fid *fid;
+	Req *r;
+	Msg *m;
+
+	threadsetname("fsthread");
+
+	a[0].op = CHANRCV;
+	a[0].c = fsclunkchan;
+	a[0].v = &fid;
+	a[1].op = CHANRCV;
+	a[1].c = fsreqchan;
+	a[1].v = &r;
+	a[2].op = CHANRCV;
+	a[2].c = sshmsgchan;
+	a[2].v = &m;
+	a[3].op = CHANEND;
+
+	for(;;){
+		switch(alt(a)){
+		case 0:
+			path = fid->qid.path;
+			switch(TYPE(path)){
+			case Qcs:
+				cs = fid->aux;
+				if(cs){
+					free(cs->resp);
+					free(cs);
+				}
+				break;
+			}
+			if(fid->omode != -1 && TYPE(path) >= Qn)
+				closeclient(client[NUM(path)]);
+			sendp(fsclunkwaitchan, nil);
+			break;
+		case 1:
+			switch(r->ifcall.type){
+			case Tattach:
+				fsattach(r);
+				break;
+			case Topen:
+				fsopen(r);
+				break;
+			case Tread:
+				fsread(r);
+				break;
+			case Twrite:
+				fswrite(r);
+				break;
+			case Tstat:
+				fsstat(r);
+				break;
+			case Tflush:
+				fsflush(r);
+				break;
+			default:
+				respond(r, "bug in fsthread");
+				break;
+			}
+			sendp(fsreqwaitchan, 0);
+			break;
+		case 2:
+			handlemsg(m);
+			break;
+		}
+	}
+}
+
+static void
+fssend(Req *r)
+{
+	sendp(fsreqchan, r);
+	recvp(fsreqwaitchan);	/* avoids need to deal with spurious flushes */
+}
+
+static void
+fsdestroyfid(Fid *fid)
+{
+	sendp(fsclunkchan, fid);
+	recvp(fsclunkwaitchan);
+}
+
+void
+takedown(Srv*)
+{
+	threadexitsall("done");
+}
+
+Srv fs = 
+{
+.attach=		fssend,
+.destroyfid=	fsdestroyfid,
+.walk1=		fswalk1,
+.open=		fssend,
+.read=		fssend,
+.write=		fssend,
+.stat=		fssend,
+.flush=		fssend,
+.end=		takedown,
+};
+
+void
+threadmain(int argc, char **argv)
+{
+	int i, fd;
+	char *host, *user, *p, *service;
+	char *f[16];
+	Msg *m;
+	static Conn c;
+
+	fmtinstall('B', mpfmt);
+	fmtinstall('H', encodefmt);
+
+	mtpt = "/net";
+	service = nil;
+	user = nil;
+	ARGBEGIN{
+	case 'B':	/* undocumented, debugging */
+		doabort = 1;
+		break;
+	case 'D':	/* undocumented, debugging */
+		debuglevel = strtol(EARGF(usage()), nil, 0);
+		break;
+	case '9':	/* undocumented, debugging */
+		chatty9p++;
+		break;
+
+	case 'A':
+		authlist = EARGF(usage());
+		break;
+	case 'c':
+		cipherlist = EARGF(usage());
+		break;
+	case 'm':
+		mtpt = EARGF(usage());
+		break;
+	case 's':
+		service = EARGF(usage());
+		break;
+	default:
+		usage();
+	}ARGEND
+
+	if(argc != 1)
+		usage();
+
+	host = argv[0];
+
+	if((p = strchr(host, '@')) != nil){
+		*p++ = '\0';
+		user = host;
+		host = p;
+	}
+	if(user == nil)
+		user = getenv("user");
+	if(user == nil)
+		sysfatal("cannot find user name");
+
+	privatefactotum();
+
+	if((fd = dial(netmkaddr(host, "tcp", "ssh"), nil, nil, nil)) < 0)
+		sysfatal("dialing %s: %r", host);
+
+	c.interactive = isatty(0);
+	c.fd[0] = c.fd[1] = fd;
+	c.user = user;
+	c.host = host;
+	setaliases(&c, host);
+
+	c.nokcipher = getfields(cipherlist, f, nelem(f), 1, ", ");
+	c.okcipher = emalloc(sizeof(Cipher*)*c.nokcipher);
+	for(i=0; i<c.nokcipher; i++)
+		c.okcipher[i] = findcipher(f[i], allcipher, nelem(allcipher));
+
+	c.nokauth = getfields(authlist, f, nelem(f), 1, ", ");
+	c.okauth = emalloc(sizeof(Auth*)*c.nokauth);
+	for(i=0; i<c.nokauth; i++)
+		c.okauth[i] = findauth(f[i], allauth, nelem(allauth));
+
+	sshclienthandshake(&c);
+
+	requestpty(&c);		/* turns on TCP_NODELAY on other side */
+	m = allocmsg(&c, SSH_CMSG_EXEC_SHELL, 0);
+	sendmsg(m);
+
+	time0 = time(0);
+	sshmsgchan = chancreate(sizeof(Msg*), 16);
+	fsreqchan = chancreate(sizeof(Req*), 0);
+	fsreqwaitchan = chancreate(sizeof(void*), 0);
+	fsclunkchan = chancreate(sizeof(Fid*), 0);
+	fsclunkwaitchan = chancreate(sizeof(void*), 0);
+
+	conn = &c;
+	procrfork(sshreadproc, &c, 8192, RFNAMEG|RFNOTEG);
+	procrfork(fsnetproc, nil, 8192, RFNAMEG|RFNOTEG);
+
+	threadpostmountsrv(&fs, service, mtpt, MREPL);
+	exits(0);
+}
+