Python: add utility function for retrieving port redirection

Slightly different versions for the same utility code are currently
present on different locations.  This unifies them all, giving
preference to the version from virtiofs_submounts.py, because of the
last tweaks added to it.

While at it, this adds a "qemu.utils" module to host the utility
function and a test.

Signed-off-by: Cleber Rosa <crosa@redhat.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Message-Id: <20210412044644.55083-4-crosa@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
[Squashed in below fix. --js]
Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Cleber Rosa <crosa@redhat.com>
Message-Id: <20210601154546.130870-2-crosa@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>

3 files changed, 41 insertions, 25 deletions

diff --git a/tests/acceptance/info_usernet.py b/tests/acceptance/info_usernet.py
new file mode 100644
index 0000000000..9c1fd903a0
--- /dev/null
+++ b/tests/acceptance/info_usernet.py
@@ -0,0 +1,29 @@
+# Test for the hmp command "info usernet"
+#
+# Copyright (c) 2021 Red Hat, Inc.
+#
+# Author:
+#  Cleber Rosa <crosa@redhat.com>
+#
+# This work is licensed under the terms of the GNU GPL, version 2 or
+# later.  See the COPYING file in the top-level directory.
+
+from avocado_qemu import Test
+
+from qemu.utils import get_info_usernet_hostfwd_port
+
+
+class InfoUsernet(Test):
+
+    def test_hostfwd(self):
+        self.vm.add_args('-netdev', 'user,id=vnet,hostfwd=:127.0.0.1:0-:22')
+        self.vm.launch()
+        res = self.vm.command('human-monitor-command',
+                              command_line='info usernet')
+        port = get_info_usernet_hostfwd_port(res)
+        self.assertIsNotNone(port,
+                             ('"info usernet" output content does not seem to '
+                              'contain the redirected port'))
+        self.assertGreater(port, 0,
+                           ('Found a redirected port that is not greater than'
+                            ' zero'))
diff --git a/tests/acceptance/linux_ssh_mips_malta.py b/tests/acceptance/linux_ssh_mips_malta.py
index 6dbd02d49d..052008f02d 100644
--- a/tests/acceptance/linux_ssh_mips_malta.py
+++ b/tests/acceptance/linux_ssh_mips_malta.py
@@ -18,6 +18,8 @@ from avocado.utils import process
 from avocado.utils import archive
 from avocado.utils import ssh
 
+from qemu.utils import get_info_usernet_hostfwd_port
+
 
 class LinuxSSH(Test):
 
@@ -70,18 +72,14 @@ class LinuxSSH(Test):
     def setUp(self):
         super(LinuxSSH, self).setUp()
 
-    def get_portfwd(self):
+    def ssh_connect(self, username, password):
+        self.ssh_logger = logging.getLogger('ssh')
         res = self.vm.command('human-monitor-command',
                               command_line='info usernet')
-        line = res.split('\r\n')[2]
-        port = re.split(r'.*TCP.HOST_FORWARD.*127\.0\.0\.1 (\d+)\s+10\..*',
-                        line)[1]
+        port = get_info_usernet_hostfwd_port(res)
+        if not port:
+            self.cancel("Failed to retrieve SSH port")
         self.log.debug("sshd listening on port:" + port)
-        return port
-
-    def ssh_connect(self, username, password):
-        self.ssh_logger = logging.getLogger('ssh')
-        port = self.get_portfwd()
         self.ssh_session = ssh.Session(self.VM_IP, port=int(port),
                                        user=username, password=password)
         for i in range(10):
diff --git a/tests/acceptance/virtiofs_submounts.py b/tests/acceptance/virtiofs_submounts.py
index ca64b76301..57a7047342 100644
--- a/tests/acceptance/virtiofs_submounts.py
+++ b/tests/acceptance/virtiofs_submounts.py
@@ -9,6 +9,8 @@ from avocado_qemu import LinuxTest, BUILD_DIR
 from avocado_qemu import wait_for_console_pattern
 from avocado.utils import ssh
 
+from qemu.utils import get_info_usernet_hostfwd_port
+
 
 def run_cmd(args):
     subp = subprocess.Popen(args,
@@ -73,27 +75,14 @@ class VirtiofsSubmountsTest(LinuxTest):
     :avocado: tags=accel:kvm
     """
 
-    def get_portfwd(self):
-        port = None
-
+    def ssh_connect(self, username, keyfile):
+        self.ssh_logger = logging.getLogger('ssh')
         res = self.vm.command('human-monitor-command',
                               command_line='info usernet')
-        for line in res.split('\r\n'):
-            match = \
-                re.search(r'TCP.HOST_FORWARD.*127\.0\.0\.1\s+(\d+)\s+10\.',
-                          line)
-            if match is not None:
-                port = int(match[1])
-                break
-
+        port = get_info_usernet_hostfwd_port(res)
         self.assertIsNotNone(port)
         self.assertGreater(port, 0)
         self.log.debug('sshd listening on port: %d', port)
-        return port
-
-    def ssh_connect(self, username, keyfile):
-        self.ssh_logger = logging.getLogger('ssh')
-        port = self.get_portfwd()
         self.ssh_session = ssh.Session('127.0.0.1', port=port,
                                        user=username, key=keyfile)
         for i in range(10):