[PATCH] devshell: Use different termination test to avoid warnings

[Jan Kiszka <jan.kiszka@web.de>]

From: Jan Kiszka <jan.kiszka@siemens.com>

As we run the terminal via a sudo chroot, OE's way of testing for the
existence of the target PID does not work. It will rather fail early due
to missing permissions (user tries to send signal to root process), and
we will wait in the unmount loop, generating warnings like

WARNING: mc:qemuamd64-buster:example-raw-0.3-r0 do_devshell: /work/build/tmp/deploy/buildchroot-target/debian-buster-amd64//home/builder/example-raw: Couldn't unmount, retrying...

This replaces the kill(pid, 0) with a test for the existence of the
corresponding /proc/<pid> directory.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 meta/lib/oe/terminal.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/meta/lib/oe/terminal.py b/meta/lib/oe/terminal.py
index 87058040..a9fb62b9 100644
--- a/meta/lib/oe/terminal.py
+++ b/meta/lib/oe/terminal.py
@@ -245,9 +245,11 @@ def spawn(name, sh_cmd, title=None, env=None, d=None):
     finally:
         os.unlink(pidfile)

+    # Test for /proc entry so that target pid can also be privileged
+    procpid = "/proc/%d" % pid
     while True:
         try:
-            os.kill(pid, 0)
+            os.stat(procpid)
             time.sleep(0.1)
         except OSError:
            return
--
2.26.1