oeqa/ssh: Handle SSHCall timeout error code

The current code in ssh.py is terminating the ssh process that
does not finish its computation in a given timeout (when timeout
is passed), the SSHCall function is returning the process error
code.

The Openssl ssh before version 8.6_p1 is returning 0 when it is
terminated, from commit 8a9520836e71830f4fccca066dba73fea3d16bda
onwards (version >= 8.6_p1) ssh is returning 255 instead.

So for version of ssh older than 8.6_p1 when the SSHCall time out,
the return code will be 0, meaning success, which is wrong.

Fix this issue checking if the process has timeout (hence it's been
terminated) and checking if the returned code is 0, in that case
set it to 255 to advertise that an error occurred.

Add a test case excercising the timeout in the SSHTest, test_ssh
test function.

(From OE-Core rev: 948fecca1db4c7a30fcca5fcf5eef95cd12efb00)

Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/core/target/ssh.py

@@ -232,11 +232,12 @@ def SSHCall(command, logger, timeout=None, **opts):
         output_raw = b''
         starttime = time.time()
         process = subprocess.Popen(command, **options)
+        has_timeout = False
         if timeout:
             endtime = starttime + timeout
             eof = False
             os.set_blocking(process.stdout.fileno(), False)
-            while time.time() < endtime and not eof:
+            while not has_timeout and not eof:
                 try:
                     logger.debug('Waiting for process output: time: %s, endtime: %s' % (time.time(), endtime))
                     if select.select([process.stdout], [], [], 5)[0] != []:
@@ -257,6 +258,10 @@ def SSHCall(command, logger, timeout=None, **opts):
                     logger.debug('BlockingIOError')
                     continue
 
+                if time.time() >= endtime:
+                    logger.debug('SSHCall has timeout! Time: %s, endtime: %s' % (time.time(), endtime))
+                    has_timeout = True
+
             process.stdout.close()
 
             # process hasn't returned yet
@@ -293,6 +298,16 @@ def SSHCall(command, logger, timeout=None, **opts):
                     pass
                 process.wait()
 
+        if has_timeout:
+            # Version of openssh before 8.6_p1 returns error code 0 when killed
+            # by a signal, when the timeout occurs we will receive a 0 error
+            # code because the process is been terminated and it's wrong because
+            # that value means success, but the process timed out.
+            # Afterwards, from version 8.6_p1 onwards, the returned code is 255.
+            # Fix this behaviour by checking the return code
+            if process.returncode == 0:
+                process.returncode = 255
+
     options = {
         "stdout": subprocess.PIPE,
         "stderr": subprocess.STDOUT,

meta/lib/oeqa/runtime/cases/ssh.py

@@ -13,6 +13,9 @@ class SSHTest(OERuntimeTestCase):
     @OETestDepends(['ping.PingTest.test_ping'])
     @OEHasPackage(['dropbear', 'openssh-sshd'])
     def test_ssh(self):
+        (status, output) = self.target.run('sleep 20', timeout=2)
+        msg='run() timed out but return code was zero.'
+        self.assertNotEqual(status, 0, msg=msg)
         (status, output) = self.target.run('uname -a')
         self.assertEqual(status, 0, msg='SSH Test failed: %s' % output)
         (status, output) = self.target.run('cat /etc/controllerimage')