[rtems-tools commit] tester: Fix TFTP server Python2 issues.

[Chris Johns]

Module:    rtems-tools
Branch:    master
Commit:    7a29b47a0ff50c49cabfe1808d3d6383e55833a5
Changeset: http://git.rtems.org/rtems-tools/commit/?id=7a29b47a0ff50c49cabfe1808d3d6383e55833a5

Author:    Chris Johns <chrisj at rtems.org>
Date:      Mon Sep  7 10:07:11 2020 +1000

tester: Fix TFTP server Python2 issues.

- Add a --show-backtrace option to make it easier for users to
  get an exception backtrace if something goes wrong.

- Fix the --packet-trace option so it actually decodes the packets

---

 tester/rt/tftpserver.py | 32 ++++++++++++++++++++++++++++----
 1 file changed, 28 insertions(+), 4 deletions(-)

diff --git a/tester/rt/tftpserver.py b/tester/rt/tftpserver.py
index 012aae4..d733301 100644
--- a/tester/rt/tftpserver.py
+++ b/tester/rt/tftpserver.py
@@ -82,6 +82,7 @@ class tftp_session(object):
         self.resends_limit = 5
         # These are here to shut pylint up
         self.block = 0
+        self.last_data = None
         self.block_size = 512
         self.timeout = 0
         self.resends = 0
@@ -95,6 +96,7 @@ class tftp_session(object):
             self.filein.close()
             self.filein = None
         self.block = 0
+        self.last_data = None
         self.block_size = 512
         self.timeout = 0
         self.resends = 0
@@ -166,7 +168,7 @@ class tftp_session(object):
             raise error.general('invalid opcode: ' + opcode)
         bdata = self._pack_bytes([code, data])
         #print(''.join(format(x, '02x') for x in bdata))
-        return bytes(bdata)
+        return bdata
 
     def _error_response(self, code, message):
         if log.tracing:
@@ -193,16 +195,19 @@ class tftp_session(object):
             self.resends = 0
             self.block += 1
             err, data = self.data_reader('read', blksize=self.block_size)
+            data = bytearray(data)
             if err != self.E_NO_ERROR:
                 return self._error_response(err, data)
             # close if the length of data is less than the block size
             if len(data) < self.block_size:
                 self.data_reader('close')
+            self.last_data = data
         else:
             self.resends += 1
             if self.resends >= self.resends_limit:
                 return self._error_response(self.E_NOT_DEFINED,
                                             'resend limit reached')
+            data = self.last_data
         return self._data_response(self.block, data)
 
     def _read_req(self, data):
@@ -387,6 +392,7 @@ class udp_handler(socketserver.BaseRequestHandler):
         # pylint: disable=too-many-locals
         # pylint: disable=broad-except
         # pylint: disable=too-many-branches
+        # pylint: disable=too-many-statements
         client_ip = self.client_address[0]
         client_port = self.client_address[1]
         client = '%s:%i' % (client_ip, client_port)
@@ -396,11 +402,12 @@ class udp_handler(socketserver.BaseRequestHandler):
                                    self.server.tftp.base,
                                    self.server.tftp.forced_file,
                                    self.server.tftp.reader)
-            response = session.process(client_ip, client_port, self.request[0])
+            data = bytearray(self.request[0])
+            response = session.process(client_ip, client_port, data)
             if response is not None:
                 if log.tracing and self.server.tftp.packet_trace:
-                    log.trace(' > ' + session.decode(client_ip, client_port,
-                                                     self.request[0]))
+                    log.trace(' > ' +
+                              session.decode(client_ip, client_port, data))
                 timeout = session.get_timeout(self.server.tftp.timeout, 1)
                 sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
                 sock.bind(('', 0))
@@ -416,6 +423,7 @@ class udp_handler(socketserver.BaseRequestHandler):
                     try:
                         data, address = sock.recvfrom(2 + 2 +
                                                       session.get_block_size())
+                        data = bytearray(data)
                         if log.tracing and self.server.tftp.packet_trace:
                             log.trace(
                                 ' > ' +
@@ -440,6 +448,8 @@ class udp_handler(socketserver.BaseRequestHandler):
         except KeyboardInterrupt:
             pass
         except Exception as exp:
+            if self.server.tftp.exception_is_raise:
+                raise
             self._notice('] tftp: %d: error: %s: %s' % (index, type(exp), exp))
         self._notice('] tftp: %d: end: %s' % (index, client))
 
@@ -472,6 +482,7 @@ class tftp_server(object):
         self.lock = threading.Lock()
         self.notices = False
         self.packet_trace = False
+        self.exception_is_raise = False
         self.timeout = timeout
         self.host = host
         self.port = port
@@ -580,6 +591,10 @@ class tftp_server(object):
         self.packet_trace = True
         self._unlock()
 
+    def except_is_raise(self):
+        '''If True a standard exception will generate a backtrace.'''
+        self.exception_is_raise = True
+
 
 def load_log(logfile):
     '''Set the log file.'''
@@ -593,6 +608,7 @@ def run(args=sys.argv, command_path=None):
     '''Run a TFTP server session.'''
     # pylint: disable=dangerous-default-value
     # pylint: disable=unused-argument
+    # pylint: disable=too-many-branches
     # pylint: disable=too-many-statements
     ecode = 0
     notice = None
@@ -621,6 +637,10 @@ def run(args=sys.argv, command_path=None):
                            help='enable trace logging of packets.',
                            action='store_true',
                            default=False)
+        argsp.add_argument('--show-backtrace',
+                           help='show the exception backtrace.',
+                           action='store_true',
+                           default=False)
         argsp.add_argument(
             '-B',
             '--bind',
@@ -665,6 +685,10 @@ def run(args=sys.argv, command_path=None):
                              argopts.base, argopts.force_file,
                              argopts.sessions)
         server.enable_notices()
+        if argopts.trace_packets:
+            server.trace_packets()
+        if argopts.show_backtrace:
+            server.except_is_raise()
 
         try:
             server.start()