From 26bd1d8dc48b8e5bc6ad8ae5221cedd9703dc473 Mon Sep 17 00:00:00 2001
From: Giacomo Tesio <giacomo@tesio.it>
Date: Wed, 25 Oct 2017 01:59:04 +0200
Subject: [PATCH] kern: fix working dir after ns clone

After sending the "clone" request to /proc/$pid/ns, the current process
will be moved to the working directory of $pid.

Otherwise the current process could still access the file and folders
on the service providing its dot, even if such service was not visible to $pid.

Also, keeping the original working directory means that the 'cd' line of the
current process's ns file would be different from that of $pid: the two ns
files must match since the command asked for a "clone".

See also https://marc.info/?l=9fans&m=150893734909969&w=2
---
 sys/src/kern/port/devproc.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/sys/src/kern/port/devproc.c b/sys/src/kern/port/devproc.c
index cae8c03..23ef89a 100644
--- a/sys/src/kern/port/devproc.c
+++ b/sys/src/kern/port/devproc.c
@@ -1281,6 +1281,11 @@ procwrite(Chan *c, void *va, long n, int64_t off)
 		pgrpcpy(up->pgrp, p->pgrp);
 		/* inherit noattach */
 		up->pgrp->noattach = p->pgrp->noattach;
+		/* inherit dot */
+		if(up->dot != nil)
+			cclose(up->dot);
+		up->dot = p->dot;
+		incref(&up->dot->r);
 		closepgrp(opg);
 		break;