Refactor SSH testing code out of individual tasks

Catch SSH errors and report failures as hints. Also some cleanups and
2to3 fixes.

19 files changed, 249 insertions, 635 deletions

diff --git a/kpov_judge/kpov_util.py b/kpov_judge/kpov_util.py
index 74b1737..9909973 100755
--- a/kpov_judge/kpov_util.py
+++ b/kpov_judge/kpov_util.py
@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
+import collections
 import itertools
 import random
 import string
@@ -12,6 +13,27 @@ import subprocess
 import glob
 import os
 
+def ssh_test(host, user, password, commands=()):
+    from pexpect import pxssh
+    results = collections.defaultdict(str)
+    try:
+        s = pxssh.pxssh(encoding='utf-8')
+        s.login(host, user, password,
+            original_prompt='~[#$] ',
+            auto_prompt_reset=False)
+        results['ssh'] = True
+        results['motd'] = s.before
+        s.set_unique_prompt()
+        for test, command in commands:
+            s.sendline(command)
+            s.prompt()
+            if test:
+                results[test] = s.before[len(command+'\r\n'):]
+        s.logout()
+    except Exception as ex:
+        results['ssh'] = str(ex)
+    return results
+
 def alnum_gen(r, l=1):
     s = ""
     for i in range(l):
diff --git a/kpov_judge/tasks/basic_network_gcc/task.py b/kpov_judge/tasks/basic_network_gcc/task.py
index c4f54bd..8f19ae8 100644
--- a/kpov_judge/tasks/basic_network_gcc/task.py
+++ b/kpov_judge/tasks/basic_network_gcc/task.py
@@ -118,39 +118,22 @@ params_meta = {
 def task(student_IP, net_prog_name, 
         P_c, P_executable, arg_c, env_c, out_stderr_c, out_stdout_c, P_script,
         param_gen_seed):
-    from pexpect import pxssh
     import random
-    conn = pxssh.pxssh()
-    conn.login(student_IP, 'student', 'vaje')
-    results = dict()
+
     r = random.Random(int(param_gen_seed))
     env_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(11)])
-    
     arg_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(13)])
     stdin_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(17)])
-    conn.sendline('ls -l {}'.format(P_script))
-    conn.prompt()
-    results['script_ls'] = conn.before
-    conn.sendline('ls -l {}'.format(P_executable))
-    conn.prompt()
-    results['executable_ls'] = conn.before
-    conn.sendline('export {}={}; {}'.format(env_c, env_val, P_script))
-    conn.prompt()
-    results['script_run'] = conn.before
-    conn.sendline('cat {}'.format(out_stderr_c))
-    conn.prompt()
-    results['script_stderr'] = conn.before
-    conn.sendline('cat {}'.format(out_stdout_c))
-    conn.prompt()
-    results['script_stdout'] = conn.before
-    conn.sendline('echo "{}" | {} "{}" 2> /dev/null'.format(stdin_val, P_executable, arg_val))
-    conn.prompt()
-    results['prog_stdout'] = conn.before
-    conn.sendline('echo "{}" | {} "{}" > /dev/null'.format(stdin_val, P_executable, arg_val))
-    conn.prompt()
-    results['prog_stderr'] = conn.before
-    conn.logout()
-    return results
+
+    return kpov_util.ssh_test(student_IP, 'student', 'vaje', (
+        ('script_ls', 'ls -l {}'.format(P_script)),
+        ('executable_ls', 'ls -l {}'.format(P_executable)),
+        ('script_run', 'export {}={}; {}'.format(env_c, env_val, P_script)),
+        ('script_stdout', 'cat {}'.format(out_stdout_c)),
+        ('script_stderr', 'cat {}'.format(out_stderr_c)),
+        ('prog_stdout', 'echo "{}" | {} "{}" 2> /dev/null'.format(stdin_val, P_executable, arg_val)),
+        ('prog_stderr', 'echo "{}" | {} "{}" > /dev/null'.format(stdin_val, P_executable, arg_val)),
+    ))
 
 def gen_params(user_id, params_meta):
     import random
@@ -198,16 +181,13 @@ def task_check(results, params):
     expected_script_stdout, expected_script_stderr, rval = test_out_gen(
         params['arg_c'], env_val 
         )
-    expected_script_stderr = 'cat {}\r\n'.format(params['out_stderr_c']) + expected_script_stderr
-    # hints += [expected_script_stderr, results['script_run'], results['script_stderr'], params['arg_c'], env_val]
     if expected_script_stderr != results['script_stderr']:
         hints += ['wrong script stderr']
     else:
         score += 2
     split_stdout = expected_script_stdout.split('\r\n')
     expected_script_stdout = "\r\n".join([ i for i in split_stdout if i.find('ma') >= 0])
-    expected_script_stdout = 'cat {}\r\n'.format(params['out_stdout_c']) + expected_script_stdout + "\r\n"
-    if expected_script_stdout != results['script_stdout']:
+    if expected_script_stdout != results['script_stdout'].strip():
         hints += ['wrong script stdout']
     else:
         score += 2
@@ -288,9 +268,9 @@ done; }&
             destroyed_c_source += 'QX'
         destroyed_c_source += c
     d.write(task_params['P_c'], destroyed_c_source)
-    d.chown(1000, 1000, params['P_c'])
+    d.chown(1000, 1000, task_params['P_c'])
     sh_path = r.choice(['/usr/share/doc', '/var/lib', '/usr/local/share', '/etc/alternatives'])
-    sh_file = sh_path + '/' + params['net_prog_name']
+    sh_file = sh_path + '/' + task_params['net_prog_name']
     d.write(sh_file, evil_shell_source)
     d.chmod(0o775, sh_file)
     d.write("/etc/rc.local", """#!/bin/sh -e
diff --git a/kpov_judge/tasks/copy_rename_100_files/task.py b/kpov_judge/tasks/copy_rename_100_files/task.py
index c658d27..f7fb3f1 100644
--- a/kpov_judge/tasks/copy_rename_100_files/task.py
+++ b/kpov_judge/tasks/copy_rename_100_files/task.py
@@ -73,20 +73,10 @@ params_meta = {
 }
 
 def task(host, folder):
-    import collections
-    from pexpect import pxssh
-    results = collections.defaultdict(str)
-    try:
-        # ideally, this would be done using a SFTP client instead of pxssh
-        s = pxssh.pxssh(encoding='utf-8')
-        s.login(host, 'test', 'test')
-        results['ssh'] = True
-        results['files'] = s.run('ls -1').split('\n'), # XXX: file may have newlines
-        results['contents'] = s.run('cat *'), # XXX: may include other files in $HOME
-        s.logout()
-    except Exception as ex:
-        results['ssh'] = str(ex)
-    return results
+    return kpov_util.ssh_test(host, 'test', 'test', (
+        ('files', 'ls -1'), # XXX: file may have newlines
+        ('contents', 'cat *'), # XXX: may include other files in $HOME
+    ))
 
 def gen_params(user_id, params_meta):
     pass
@@ -96,10 +86,13 @@ def task_check(results, params):
 
     score = 0
     hints = []
+    if results['ssh'] is not True:
+        hints += ['ssh failed: ' + results['ssh']]
+
     matched = 0
     files = os.listdir(params['folder'])
     for fn in files:
-        if fn in results['files']:
+        if fn in results['files'].splitlines():
             matched += 1
     if matched > 0:
         score = 1
@@ -113,12 +106,12 @@ def task_check(results, params):
         score += 3 
     else:
         hints += ["wrong number of files"]
-    rl = results['contents'].split('\n')
+    rl = results['contents'].splitlines()
     rl.sort()
     tl = []
     for fn in files:
-        with open(fn) as f:
-            tl += f.read().upper().split('\n')
+        with open(os.path.join(params['folder'], fn)) as f:
+            tl += f.read().upper().splitlines()
     tl.sort()
     if rl == tl:
         score += 4
diff --git a/kpov_judge/tasks/copy_rename_20_files_tail_env/task.py b/kpov_judge/tasks/copy_rename_20_files_tail_env/task.py
index d7f0cc6..b7970e7 100644
--- a/kpov_judge/tasks/copy_rename_20_files_tail_env/task.py
+++ b/kpov_judge/tasks/copy_rename_20_files_tail_env/task.py
@@ -118,9 +118,16 @@ params_meta = {
 def task(IP_malishell, file_rename_dirname, mv_src_dir, mv_dst_dir, cowsay_string, curl_fname, wc_dirname):
     import collections
     import os
-    from pexpect import pxssh
 
-    commands = [
+    # TOD: (polz) this has to be changed! Get a move on!
+    #
+    # sv: Z primozem lavricem sva skusala nekaj narediti
+    # Ker gen params ni narejen, sklepam da je "Mapa" na namizju,
+    # imena datotek pa so: 1,1-,2,2-,3,3-,4,5,6,7,8,9,.mama1,mama2,mama3,mama4,mama5,mojimenik,novi,oce1
+    # v mojimenik se nahaja mojimenikfile
+    # mama2 vsebuje "mama"
+    #Stirje subt-aski dodani.By Mihec.
+    results = kpov_util.ssh_test(IP_malishell, 'student', 'vaje', (
         ('preimenuj', '/bin/ls -a1 {}'.format(file_rename_dirname)),
         ('pre_mv_src', '/bin/ls -a1 {}'.format(mv_src_dir)),
         ('pre_mv_dst', '/bin/ls -a1 {}'.format(mv_dst_dir)),
@@ -144,29 +151,7 @@ def task(IP_malishell, file_rename_dirname, mv_src_dir, mv_dst_dir, cowsay_strin
         ('cowsay', 'cowsay "{}"'.format(cowsay_string)),
         ('wc_origfile', 'cat {}/count.txt'.format(wc_dirname)),
         ('wc_lines', 'cat {}/lines.txt'.format(wc_dirname)),
-    ]
-
-    # TOD: (polz) this has to be changed! Get a move on!
-    #
-    # sv: Z primozem lavricem sva skusala nekaj narediti    
-    # Ker gen params ni narejen, sklepam da je "Mapa" na namizju,
-    # imena datotek pa so: 1,1-,2,2-,3,3-,4,5,6,7,8,9,.mama1,mama2,mama3,mama4,mama5,mojimenik,novi,oce1
-    # v mojimenik se nahaja mojimenikfile
-    # mama2 vsebuje "mama"
-    #Stirje subt-aski dodani.By Mihec.
-    results = collections.defaultdict(str)
-    try:
-        s = pxssh.pxssh(encoding='utf-8')
-        s.login(IP_malishell, 'student', 'vaje')
-        results['ssh'] = True
-        for test, command in commands:
-            s.sendline(command)
-            s.prompt()
-            if test:
-                results[test] = s.before
-        s.logout()
-    except Exception as ex:
-        results['ssh'] = str(ex)
+    ))
 
     try:
         results['curl_env'] = os.environ['images']
@@ -309,11 +294,8 @@ def task_check(results, params):
     else:
         hints += ["wrong image count"]
     task6_ok = True
-    wc_cat_str = 'cat {}/lines.txt'.format(params['wc_dirname'])
-    if not wc_cat_str == results['wc_lines'][:len(wc_cat_str)]:
-        task6_ok = False
     try:
-        assert int(results['wc_lines'][len(wc_cat_str):].strip()) == int(params['wc_n_lines'])
+        assert int(results['wc_lines'].strip()) == int(params['wc_n_lines'])
     except:
         task6_ok = False
     if task6_ok:
diff --git a/kpov_judge/tasks/custom_rdate/task.py b/kpov_judge/tasks/custom_rdate/task.py
index 51f5baa..da8313c 100644
--- a/kpov_judge/tasks/custom_rdate/task.py
+++ b/kpov_judge/tasks/custom_rdate/task.py
@@ -39,10 +39,6 @@ computers = {
         'disks': [
             {   'name': 'student-rdate',
             },
-            #{   'name': 'CDROM',
-            #    'options':{'readonly': True},
-            #    'parts': [],# no parts, no mounting.
-            #}
         ],
         'network_interfaces': [{'network': 'net1'}],
         'flavor': 'm1.tiny',
@@ -52,12 +48,7 @@ computers = {
     'SimpleArbiter': {
         'disks': [
             {   'name': 'simpleArbiterDhcpGWRdate',
-                # attempt automount
             },
-            #{   'name': 'CDROM',
-            #    'options': {'readonly': True},
-            #    'parts': [{'dev': 'b1', 'path': '/cdrom'}],
-            #},
         ],
         'network_interfaces': [{'network': 'net1'}, {'network': 'test-net'}],
         'flavor': 'm1.tiny',
@@ -75,37 +66,26 @@ params_meta = {
 }
 
 def task(IP_RDATECLIENT, PROGRAM_FILENAME):
-    import pexpect
-    import paramiko
-    from paramiko import SSHClient
+    import collections
+    import base64
     import random
     import struct
-    import base64
-    results = dict()
-    peer_user = 'test'
-    peer_passwd = 'test'
-    client = SSHClient()
-    client.load_system_host_keys()
-    client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
-    client.connect(IP_RDATECLIENT, username=peer_user, password=peer_passwd)
-    #client.login(IP_RDATECLIENT, peer_user, peer_passwd)
+    import pexpect
+
     r = random.Random(PROGRAM_FILENAME)
+    results = collections.defaultdict(str)
+    tests = []
     for i in range(10):
-        stdin, stdout, stderr = client.exec_command(
-            '~/{}'.format(PROGRAM_FILENAME))
         data = struct.pack("!I", r.randint(0, 2**32))
-        stdin.write(data)
-        results['in_' + str(i)] = base64.encodestring(data)
-        results['out_' + str(i)] = stdout.read()
-    stdin, stdout, stderr = client.exec_command(
-        'date -u +"%s"')
-    #client.sendline('date -u "%s"')
-    #client.prompt()
-    results['date'] = stdout.read()
+        results['in_'+str(i)] = data_ascii = base64.encodestring(data)
+        tests += [('out_'+str(i), 'echo "{}" | base64 -d | ~/{}'.format(data_ascii.decode().strip(), PROGRAM_FILENAME))]
+    tests += [('date', 'date -u +"%s"')]
+
+    results.update(
+        kpov_util.ssh_test(IP_RDATECLIENT, 'test', 'test', tests))
     results['ldate'] = pexpect.run('date -u +"%s"')
-    client.close()
-    return results
 
+    return results
 
 #Dolocil sem tri parametre in sicer jih lahko vidite v prams_meta,
 #zato prosim da jih upostevate v naslednih nalogah.
@@ -124,7 +104,7 @@ def task_check(results, params):
     import random
     import struct
     import base64
-    # print results
+
     r = random.Random(params['PROGRAM_FILENAME'])
     score = 0.0
     hints = []
@@ -139,7 +119,7 @@ def task_check(results, params):
             score += 0.5
         else:
             hints += ["wrong convert"]
-            # print str(struct.unpack("!I", data)[0]), res.strip()
+
     if abs(int(results['ldate']) + \
         int(params['RDATE_OFFSET']) - int(results['date'])) < 3:
         score += 5
@@ -148,9 +128,6 @@ def task_check(results, params):
     return score, hints
 
 def prepare_disks(templates, task_params, global_params):
-#    d = templates['simpleArbiterDhcp']
-#    print templates
-#    print params
     d = templates['simpleArbiterDhcpGWRdate']
     s1 = """service "time_tcp" {{
     enabled yes;
@@ -170,7 +147,7 @@ import time
 import sys
 
 offset = int(sys.argv[1])
-t = time.time() + 2208988800 + offset
+t = time.time() + offset # used to have + 2208988800
 sys.stdout.write(struct.pack("!I", int(t)))
 """
     d.write('/usr/local/bin/kpovrdate', s2)
diff --git a/kpov_judge/tasks/dhcp_dns_predefined_ip/task.py b/kpov_judge/tasks/dhcp_dns_predefined_ip/task.py
index 2559507..9d98ea4 100644
--- a/kpov_judge/tasks/dhcp_dns_predefined_ip/task.py
+++ b/kpov_judge/tasks/dhcp_dns_predefined_ip/task.py
@@ -65,37 +65,19 @@ params_meta = {
 }
 
 def task(IP_server, IP_client, MAC_client, HOSTNAME_X):
-    from pexpect import pxssh
-    #import pexpect
-    results = dict()
-    peer_user = 'student'
-    peer_passwd = 'vaje'
-    sA = pxssh.pxssh()
-    sB = pxssh.pxssh()
-    #prijavimo se na streznik (IP_NM je IP nalov streznika)
-    sA.login(IP_server, peer_user, peer_passwd)
-    #prijavimo se na  klienta (IP_static je IP naslov klienta)
-    sB.login(IP_client, peer_user, peer_passwd)
-    sA.sendline('sudo ps -A')
-    sA.sendline(peer_passwd)
-    sA.prompt()
-    results['dhcp_proces'] = sA.before
-    # tukaj dobimo podatke, ce je na IP_NM naslovu res postavljen DHCP streznik
-    sB.sendline('sudo dhcping -s {} -h {} -c {}'.format(IP_server, MAC_client, IP_client))
-    sB.sendline(peer_passwd)
-    sB.prompt()
-    results['dhcp'] = sB.before
-    # tukaj pa dobimo podatek, ce je IP, ki ga vraca DNS streznik za HOSTNAME_X pravilen
-    sB.sendline('nslookup {}'.format(HOSTNAME_X))
-    sB.prompt()
-    results['dns_hostname'] = sB.before
-    sB.sendline('/sbin/ifconfig')
-    sB.prompt()
-    results['client_IP'] = sB.before
-    sA.logout()
-    sB.logout()
-    return results
+    tests = {
+        IP_server: (
+            ('dhcp_proces', 'sudo ps -A')),
+        IP_client: (
+            ('dhcp', 'sudo dhcping -s {} -h {} -c {}'.format(IP_server, MAC_client, IP_client)),
+            ('dns_hostname', 'nslookup {}'.format(HOSTNAME_X)),
+            ('client_IP', '/sbin/ifconfig')),
+    }
 
+    results = collections.defaultdict(str)
+    for host, host_tests in tests.items():
+        results.update(kpov_util.ssh_test(host, 'student', 'vaje', host_tests))
+    return results
 
 def gen_params(user_id, params_meta):
     params = dict()
@@ -105,7 +87,6 @@ def gen_params(user_id, params_meta):
     params['HOSTNAME_X'] = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ') for i in range(5)])
     return params
 
-
 def task_check(results, params):
     import re
     score = 0
diff --git a/kpov_judge/tasks/edit_find_grep_compile_convert/task.py b/kpov_judge/tasks/edit_find_grep_compile_convert/task.py
index a2f1ed0..23825c5 100644
--- a/kpov_judge/tasks/edit_find_grep_compile_convert/task.py
+++ b/kpov_judge/tasks/edit_find_grep_compile_convert/task.py
@@ -191,35 +191,24 @@ params_meta = {
 }
 
 def task(testip, testuser, passwd, magicstr, dstfile, progname, pubseed):
-    from pexpect import pxssh
     import random
-    N_TITA = 40
-    target = pxssh.pxssh()
-    target.login(testip, testuser, passwd)
-    target.sendline('ls -l ~/{}'.format(dstfile))
-    target.prompt()
-    dst_ls = target.before
-    target.sendline('cat ~/{}'.format(dstfile))
-    target.prompt()
-    dst_file_contents = target.before
-    target.sendline('ls ~/'.format(dstfile))
-    target.prompt()
-    home_ls = target.before
-    results = {
-        'dst_ls': dst_ls,
-        'dst_file_contents': dst_file_contents,
-        'home_ls': home_ls,
-    }
-    tita_return = ""
+
     r = random.Random(pubseed)
+    tests = [
+        ('dst_ls', 'ls -l ~/{}'.format(dstfile)),
+        ('dst_file_contents', 'cat ~/{}'.format(dstfile)),
+        ('home_ls', 'ls ~/'.format(dstfile)),
+    ]
+
+    N_TITA = 40
     for i in range(N_TITA):
         b = r.randint(0, 7)
         x = oct(r.randint(37, 127)).replace('o', '')
-        target.sendline('echo -e "\\{}" | ~/{} {}'.format(x, progname, b))
-        target.prompt()
-        tita_return += target.before
-    results['tita_return'] = tita_return
-    target.logout()
+        tests += [('tita-{:02}'.format(i), 'echo -e "\\{}" | ~/{} {}'.format(x, progname, b))]
+
+    results = kpov_util.ssh_test(testip, testuser, passwd, tests)
+    results['tita_return'] = ''.join(val for key, val in results.items() if key.startswith('tita-'))
+
     return results
 
 def gen_params(user_id, params_meta):
@@ -258,11 +247,6 @@ def task_check(results, params):
         x = start + mid + end
         hidden_contents += x + "\r\n"
     expected_contents = hidden_contents
-    #expected_contents = re.sub(r"^po.*lz\r$", 
-    #                           r"pokakalz\r", 
-    #                           hidden_contents, 
-    #                           re.MULTILINE)
-    expected_contents = "cat ~/{}\r\n".format(params['dstfile']) + expected_contents
     if results["dst_file_contents"] == expected_contents:
         score += 3
     else:
@@ -275,7 +259,7 @@ def task_check(results, params):
                 break
         hints += ["wrong file contents\n" + str(diff_pos[1])]
         #hints += ["wrong file contents"]
-    expected_ls = "ls -l ~/{dstfile}\r\n-rw--w---- 1 {testuser} bilbo .*{dstfile}.*\r\n".format(**params)
+    expected_ls = "-rw--w---- 1 {testuser} bilbo .*{dstfile}.*\r\n".format(**params)
     if re.match(expected_ls, results["dst_ls"]):
         score += 3
     else:
@@ -290,7 +274,6 @@ def task_check(results, params):
         b = r.randint(0, 7)
         x_i = r.randint(37, 127)
         x = oct(x_i).replace('o', '')
-        expected_tita += 'echo -e "\\{}" | ~/{} {}\r\n'.format(x, params['progname'], b)
         if x_i & (1 << b):
             expected_tita += "ta\r\n"
         else:
@@ -298,7 +281,6 @@ def task_check(results, params):
     if results["tita_return"] == expected_tita:
         score += 2
     else:
-        #hints += [u"program output incorrect\n" + results["tita_return"] + expected_tita]
         hints += ["program output incorrect\n" + results["tita_return"]]
     return score, hints
 
@@ -306,10 +288,7 @@ def task_check(results, params):
 def prepare_disks(templates, task_params, global_params):
     import random
     import os
-    #print "Haha!"
-    #print params
-    #print templates
-    d = templates['student-entrance2']
+
     # first create the file contents to make it easyer to check.
     hidden_contents = task_params['magicstr']
     r = random.Random(task_params['rndseed'])
@@ -318,12 +297,15 @@ def prepare_disks(templates, task_params, global_params):
         x += "".join([r.choice("uiasdfghjkyxcvbnm1234567890ASDFGHJKYZXCVBNM") for i in range(60)])
         x += r.choice(["lz", "1z", "Iz", "iz", "l2", "I2", "12"])
         hidden_contents += x + "\n"
+
     # create hidden file
     dir_list = ['Qlipper', 'Thunar', 'blender', 'autostart', 'kazam', 'mc', 'netsurf', 'pulse', 'qupzilla', 'radare2', 'teamviewer', 'texstudio', 'vlc']
     ending_list = ['rc', '.conf', '']
     start_list = ['net', 'dev', 'doc', 'lib', 'time', 'conf']
     r.shuffle(dir_list)
     file_letters = ["mod", "co"]
+
+    d = templates['student-entrance2']
     for potential_dir in dir_list:
         try:
             potential_dir = os.path.join('/home/bilbo/.config', potential_dir)
@@ -344,6 +326,3 @@ def prepare_disks(templates, task_params, global_params):
     # TODO create some additional files 
     
     write_default_config(templates['simpleArbiterDhcpGW'], global_params)
-    # finish here
-    # rename
-
diff --git a/kpov_judge/tasks/ldap_import/task.py b/kpov_judge/tasks/ldap_import/task.py
index d66509b..85862ad 100644
--- a/kpov_judge/tasks/ldap_import/task.py
+++ b/kpov_judge/tasks/ldap_import/task.py
@@ -21,10 +21,6 @@ computers = {
         'disks': [
             {   'name': 'maliNetworkManager',
             },
-            #{   'name': 'CDROM',
-            #    'options':{'readonly': True},
-            #    'parts': [],# no parts, no mounting.
-            #}
         ],
         'network_interfaces': [{'network': 'net1'}],
         'flavor': 'm1.tiny',
@@ -35,10 +31,6 @@ computers = {
         'disks': [
             {   'name': 'maliBrezNetworkManager',
             },
-            #{   'name': 'CDROM',
-            #    'options':{'readonly': True},
-            #    'parts': [],# no parts, no mounting.
-            #}
         ],
         'network_interfaces': [{'network': 'net1'}],
         'flavor': 'm1.tiny',
@@ -48,12 +40,7 @@ computers = {
     'SimpleArbiter': {
         'disks': [
             {   'name': 'simpleArbiterDhcp',
-                # attempt automount
             },
-            #{   'name': 'CDROM',
-            #    'options': {'readonly': True},
-            #    'parts': [{'dev': 'b1', 'path': '/cdrom'}],
-            #},
         ],
         'network_interfaces': [{'network': 'net1'}, {'network': 'test-net'}],
         'flavor': 'm1.tiny',
diff --git a/kpov_judge/tasks/mock_entrance_exam/task.py b/kpov_judge/tasks/mock_entrance_exam/task.py
index 1d113b5..68f59cb 100644
--- a/kpov_judge/tasks/mock_entrance_exam/task.py
+++ b/kpov_judge/tasks/mock_entrance_exam/task.py
@@ -136,42 +136,22 @@ params_meta = {
 def task(student_IP, net_prog_name, 
         P_c, P_executable, arg_c, env_c, out_stderr_c, out_stdout_c, P_script,
         param_gen_seed):
-    from pexpect import pxssh
     import random
-    results = {}
+
     r = random.Random(int(param_gen_seed))
-    try:
-        s = pxssh.pxssh(encoding='utf-8')
-        s.login(student_IP, 'student', 'vaje')
-        results['ssh'] = True
-        env_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(11)])
-        arg_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(13)])
-        stdin_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(17)])
-        s.sendline('ls -l {}'.format(P_script))
-        s.prompt()
-        results['script_ls'] = s.before
-        s.sendline('ls -l {}'.format(P_executable))
-        s.prompt()
-        results['executable_ls'] = s.before
-        s.sendline('export {}={}; {}'.format(env_c, env_val, P_script))
-        s.prompt()
-        results['script_run'] = s.before
-        s.sendline('cat {}'.format(out_stderr_c))
-        s.prompt()
-        results['script_stderr'] = s.before
-        s.sendline('cat {}'.format(out_stdout_c))
-        s.prompt()
-        results['script_stdout'] = s.before
-        s.sendline('echo "{}" | {} "{}" 2> /dev/null'.format(stdin_val, P_executable, arg_val))
-        s.prompt()
-        results['prog_stdout'] = s.before
-        s.sendline('echo "{}" | {} "{}" > /dev/null'.format(stdin_val, P_executable, arg_val))
-        s.prompt()
-        results['prog_stderr'] = s.before
-        s.logout()
-    except pxssh.ExceptionPxssh as ex:
-        results['ssh'] = str(ex)
-    return results
+    env_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(11)])
+    arg_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(13)])
+    stdin_val = "".join([r.choice('ABCDEFGHIJKLMNPRSTUVZ012345') for i in range(17)])
+
+    return kpov_util.ssh_test(student_IP, 'student', 'vaje', (
+        ('script_ls', 'ls -l {}'.format(P_script)),
+        ('executable_ls', 'ls -l {}'.format(P_executable)),
+        ('script_run', 'export {}={}; {}'.format(env_c, env_val, P_script)),
+        ('script_stderr', 'cat {}'.format(out_stderr_c)),
+        ('script_stdout', 'cat {}'.format(out_stdout_c)),
+        ('prog_stdout', 'echo "{}" | {} "{}" 2> /dev/null'.format(stdin_val, P_executable, arg_val)),
+        ('prog_stderr', 'echo "{}" | {} "{}" > /dev/null'.format(stdin_val, P_executable, arg_val)),
+    ))
 
 def gen_params(user_id, params_meta):
     import random
diff --git a/kpov_judge/tasks/nat_port_forward/task.py b/kpov_judge/tasks/nat_port_forward/task.py
index 7613c4a..e96a8e7 100644
--- a/kpov_judge/tasks/nat_port_forward/task.py
+++ b/kpov_judge/tasks/nat_port_forward/task.py
@@ -19,10 +19,6 @@ computers = {
         'disks': [
             {   'name': 'maliNetworkManager',
             },
-            #{   'name': 'CDROM',
-            #    'options':{'readonly': True},
-            #    'parts': [],# no parts, no mounting.
-            #}
         ],
         'network_interfaces': [{'network': 'test-net'}],
         'flavor': 'm1.tiny',
@@ -33,10 +29,6 @@ computers = {
         'disks': [
             {   'name': 'student-NATServer',
             },
-            #{   'name': 'CDROM',
-            #    'options':{'readonly': True},
-            #    'parts': [],# no parts, no mounting.
-            #}
         ],
         'network_interfaces': [{'network': 'net1'}, {'network': 'test-net'}],
         'flavor': 'm1.tiny',
@@ -46,12 +38,7 @@ computers = {
     'SimpleArbiter': {
         'disks': [
             {   'name': 'simpleArbiter',
-                # attempt automount
             },
-            #{   'name': 'CDROM',
-            #    'options': {'readonly': True},
-            #    'parts': [{'dev': 'b1', 'path': '/cdrom'}],
-            #},
         ],
         'network_interfaces': [{'network': 'net1'}],
         'flavor': 'm1.tiny',
@@ -70,18 +57,15 @@ params_meta = {
 }
 
 def task(IP_TEST_CLIENT, IP_NAT, PORT_OUTER, PORT_INNER, NET):
-    import pexpect
-    from pexpect import pxssh
-    import re
     import random
     import time
-    # return None
-    peer_user = 'student'
-    peer_password = 'vaje'
+    import pexpect
+    from pexpect import pxssh
+
     results = dict()
-    tcpdump = pexpect.spawn('sudo /usr/sbin/tcpdump src host {} and dst port {}'.format(IP_TEST_CLIENT, PORT_INNER))
-    sshconn = pxssh.pxssh()
-    sshconn.login(IP_TEST_CLIENT, peer_user, peer_password)
+    tcpdump = pexpect.spawn('sudo /usr/sbin/tcpdump src host {} and dst port {}'.format(IP_TEST_CLIENT, PORT_INNER), encoding='utf-8')
+    sshconn = pxssh.pxssh(encoding='utf-8')
+    sshconn.login(IP_TEST_CLIENT, 'student', 'vaje')
     r = random.Random()
     k = r.randint(10, 15)
     results['pre_nc'] = str(k)
@@ -92,7 +76,7 @@ def task(IP_TEST_CLIENT, IP_NAT, PORT_OUTER, PORT_INNER, NET):
         sshconn.sendintr()
         sshconn.prompt()
         results['nc_pre'] += sshconn.before
-    nc = pexpect.spawn('nc -l -p {}'.format(PORT_INNER))
+    nc = pexpect.spawn('nc -l -p {}'.format(PORT_INNER), encoding='utf-8')
     sshconn.sendline()
     sshconn.prompt()
     sshconn.sendline("nc {} {}".format(IP_NAT, PORT_OUTER))
@@ -102,8 +86,8 @@ def task(IP_TEST_CLIENT, IP_NAT, PORT_OUTER, PORT_INNER, NET):
     sshconn.sendintr()
     nc.expect(pexpect.EOF)
     results['nc_ret'] = nc.before
-    results['route'] = pexpect.run('/sbin/ip route list 0/0')
-    results['traceroute'] = pexpect.run('traceroute {}'.format(IP_TEST_CLIENT)) 
+    results['route'] = pexpect.run('ip route list 0/0', encoding='utf-8')
+    results['traceroute'] = pexpect.run('traceroute {}'.format(IP_TEST_CLIENT), encoding='utf-8')
     # wait for traceroute
     time.sleep(10)
     tcpdump.sendintr()
@@ -118,7 +102,6 @@ def task(IP_TEST_CLIENT, IP_NAT, PORT_OUTER, PORT_INNER, NET):
 def gen_params(user_id, params_meta):
     params = dict()
     r = random.Random(user_id)
-    # IP_NM, DNS_NM, IP_static, DNS_static)
     params['PORT_INNER'] = str(r.randint(6000, 10000))
     params['PORT_OUTER'] = str(r.randint(10001, 15000))
     params['NET'] = kpov_util.IPv4_subnet_gen(r, "10.36.0.0/14", 24)
@@ -127,12 +110,6 @@ def gen_params(user_id, params_meta):
 def task_check(results, params):
     import re
     import pickle
-    #if results is None:
-    #    with open('bla.pickle') as f: 
-    #        results = cPickle.load(f)
-    #else:
-    #    with open('bla.pickle', 'w') as f:
-    #        cPickle.dump(results, f)
     score = 0
     hints = []
     local_net = params['NET'][:params['NET'].rfind('.')]
diff --git a/kpov_judge/tasks/nat_vlc/task.py b/kpov_judge/tasks/nat_vlc/task.py
index 89d0f13..ed24b95 100644
--- a/kpov_judge/tasks/nat_vlc/task.py
+++ b/kpov_judge/tasks/nat_vlc/task.py
@@ -20,7 +20,7 @@ ustvarite še uporabnika {IP_NAT_user}.
 Poskrbi, da bo SimpleArbiter prek DHCP dobil naslov {IP_simple}.
 Poskrbi, da bo NATServer deloval kot prehod za SimpleArbiter in izvajal NAT.
 """,
-	'en':"""
+        'en':"""
 Set up two virtual machines - SimpleArbiter (using the disc simpleArbiter) and
 NATServer. NATServer should have two network adapters. Connect the first
 adapter to SimpleArbiter and the second adapter to the Internet. Configure the
@@ -38,12 +38,7 @@ computers = {
     'NATServer': {
         'disks': [
             {   'name': 'student-NATServer',
-                # attempt automount
             },
-            #{   'name': 'CDROM',
-            #    'options': {'readonly': True},
-            #    'parts': [{'dev': 'b1', 'path': '/cdrom'}],
-            #},
         ],
         'network_interfaces': [{'network': 'net1'}, {'network': 'test-net'}],
         'flavor': 'm1.tiny',
@@ -53,17 +48,11 @@ computers = {
         'disks': [
             {   'name': 'simpleArbiter',
             },
-            #{   'name': 'CDROM',
-            #    'options':{'readonly': True},
-            #    'parts': [],# no parts, no mounting.
-            #}
         ],
         'network_interfaces': [{'network': 'net1'}],
         'flavor': 'm1.tiny',
         'config_drive': False
-
     },
-
 }
 
 networks = { 'net1': {'public': False}, 'test-net': {'public': True} }
@@ -77,24 +66,19 @@ params_meta = {
 }
 
 def task(IP_simple, IP_NAT, IP_NAT_user, IP_NAT_passwd):
-    from pexpect import pxssh
     import pexpect
-    results = dict()
-    # Connect to NAT
-    povezava = pxssh.pxssh()
-    povezava.login(IP_NAT,IP_NAT_user,IP_NAT_passwd)
+
+    results = kpov_util.ssh_test(IP_NAT, IP_NAT_user, IP_NAT_passwd, (
+        ('IP_NAT_ip_forward', 'cat /proc/sys/net/ipv4/ip_forward'),
+    ))
+
     # Check if If IP_simple is connected to NAT
-    results['IP_simple_ping_to_NAT'] = pexpect.run('ping -c 5 {}'.format(IP_NAT))
+    results['IP_simple_ping_to_NAT'] = pexpect.run('ping -c 5 {}'.format(IP_NAT), encoding='utf-8')
     # Check routing table on IP_simple
-    results['IP_simple_routing_table'] = pexpect.run('/sbin/route -n')
+    results['IP_simple_routing_table'] = pexpect.run('route -n', encoding='utf-8', env={'PATH': '/bin:/sbin'})
     # Tracert Check if IP_simple is connected to internet
-    povezava.prompt()
-    results['IP_simple_to_internet'] = pexpect.run('/usr/sbin/traceroute 8.8.8.8')
-    povezava.prompt()
-    povezava.sendline('cat /proc/sys/net/ipv4/ip_forward')
-    povezava.prompt()
-    results['IP_NAT_ip_forward'] = povezava.before
-    povezava.logout()
+    results['IP_simple_to_internet'] = pexpect.run('traceroute 8.8.8.8', encoding='utf-8')
+
     return results
     
 def gen_params(user_id, params_meta):
@@ -121,8 +105,8 @@ def task_check(results, params):
         score += 3
     else:
         hints.append("Ping to NAT incorrect")
-    if results['IP_NAT_ip_forward']=="cat /proc/sys/net/ipv4/ip_forward\r\n1\r\n":
-	score += 2
+    if results['IP_NAT_ip_forward'].strip() == "1":
+        score += 2
     else:
         hints.append("ip_forward not set on NAT?")
     rs = r"1 +{0} +\({0}\)".format(params['IP_NAT'])
diff --git a/kpov_judge/tasks/openvpn_multiple_hops/task.py b/kpov_judge/tasks/openvpn_multiple_hops/task.py
index 5d6b033..73a6c53 100644
--- a/kpov_judge/tasks/openvpn_multiple_hops/task.py
+++ b/kpov_judge/tasks/openvpn_multiple_hops/task.py
@@ -120,144 +120,32 @@ params_meta = {
 

 

 def task(IP_SimpleArbiterLAN, IP_VPNClient1, IP_LANClient1, IP1_VPNClient2, IP2_VPNClient2, IP_LANClient2, IP_VPNClient3, IP_LANClient3):

-     

-    from pexpect import pxssh    # Used to set up an SSH connection to a remote machine

-    import pexpect  # Allows the script to spawn a child application and control it as if a human were typing commands

-    

-    

-    # The necessary things we need to check if the task was performed correctly

-    results = dict()

-    

-    # The login params (these must be used on the machines!)

-    peer_user = 'test'

-    peer_passwd = 'test'

-   

-    ###

-    # Sets up the SSH connections to the machines

-    ###

-    # VPNClient1

-    sC1 = pxssh.pxssh()

-    

-    # Logs in to the machines with the default login params

-    sC1.login(

-        IP_LANClient1,

-        peer_user,

-        peer_passwd

-    )

-

-    ######

-    # Ukazi za A

-    ######

-

-    # ifconfig -a

-    sC1.sendline('/sbin/ifconfig -a')

-    sC1.prompt()

-    results['VPNClient1_ifconfig'] = sC1.before

-    

-    # route -n

-    sC1.sendline('/sbin/route -n')

-    sC1.prompt()

-    results['VPNClient1_route'] = sC1.before

-

-    # ping C2

-    sC1.sendline('ping -c 3 {}'.format(IP1_VPNClient2))

-    sC1.prompt()

-    results['VPNClient1_ping1_C2'] = sC1.before

-

-    sC1.sendline('ping -c 3 {}'.format(IP2_VPNClient2))

-    sC1.prompt()

-    results['VPNClient1_ping2_C2'] = sC1.before

-

-    # ping C3

-    sC1.sendline('ping -c 3 {}'.format(IP_VPNClient3))

-    sC1.prompt()

-    results['VPNClient1_ping_C3'] = sC1.before

-

-    # traceroute na C

-

-    sC1.sendline('traceroute {}'.format(IP_VPNClient3))

-    sC1.prompt()

-    results['VPNClient1_traceroute_C3'] = sC1.before

-

-    sC1.logout()

-

-    ######

-    # Ukazi za B

-    ######

-

-    # VPNClient2

-    sC2 = pxssh.pxssh()

-

-    sC2.login(

-        IP_LANClient2,

-        peer_user,

-        peer_passwd

-    )

-    

-

-    # ifconfig -a

-    sC2.sendline('/sbin/ifconfig -a')

-    sC2.prompt()

-    results['VPNClient2_ifconfig'] = sC2.before

-    

-    # route -n

-    sC2.sendline('/sbin/route -n')

-    sC2.prompt()

-    results['VPNClient2_route'] = sC2.before

-

-    # ping C2

-    sC2.sendline('ping -c 3 {}'.format(IP_VPNClient1))

-    sC2.prompt()

-    results['VPNClient2_ping_C1'] = sC2.before

-

-    # ping C3

-

-    sC2.sendline('ping -c 3 {}'.format(IP_VPNClient3))

-    sC2.prompt()

-    results['VPNClient2_ping_C3'] = sC2.before

-

-    sC2.logout()

-

-    ######

-    # Ukazi za C

-    ######

-

-    # VPNClient3

-    sC3 = pxssh.pxssh()

-

-    sC3.login(

-        IP_LANClient3,

-        peer_user,

-        peer_passwd

-    )

-

-    # ifconfig -a

-    sC3.sendline('/sbin/ifconfig -a')

-    sC3.prompt()

-    results['VPNClient3_ifconfig'] = sC3.before

-

-    # route -n

-    sC3.sendline('/sbin/route -n')

-    sC3.prompt()

-    results['VPNClient3_route'] = sC3.before

-

-    # ping C2

-    sC3.sendline('ping -c 3 {}'.format(IP2_VPNClient2))

-    sC3.prompt()

-    results['VPNClient3_ping_C2'] = sC3.before

-

-    # ping C3

-    sC3.sendline('ping -c 3 {}'.format(IP_VPNClient1))

-    sC3.prompt()

-    results['VPNClient3_ping_C1'] = sC3.before

-

-    # traceroute na C

-    sC3.sendline('traceroute {}'.format(IP_VPNClient1))

-    sC3.prompt()

-    results['VPNClient3_traceroute_C1'] = sC3.before

+    tests = {

+        ('VPNClient1', IP_LANClient1): [

+            ('VPNClient1_ping_C2', 'ping -c 3 {}'.format(IP1_VPNClient2)),

+            ('VPNClient1_ping_C3', 'ping -c 3 {}'.format(IP_VPNClient3)),

+            ('VPNClient1_traceroute_C3', 'traceroute {}'.format(IP_VPNClient3)),

+        ],

+        ('VPNClient2', IP_LANClient2): [

+            ('VPNClient2_ping_C1', 'ping -c 3 {}'.format(IP_VPNClient1)),

+            ('VPNClient2_ping_C3', 'ping -c 3 {}'.format(IP_VPNClient3)),

+        ],

+        ('VPNClient3', IP_LANClient3): [

+            ('VPNClient3_ping_C1', 'ping -c 3 {}'.format(IP_VPNClient1)),

+            ('VPNClient3_ping_C2', 'ping -c 3 {}'.format(IP2_VPNClient2)),

+            ('VPNClient3_traceroute_C1', 'traceroute {}'.format(IP_VPNClient1)),

+        ],

+    }

 

-    sC3.logout()

+    for (name, host), host_tests in tests.items():

+        host_tests += [

+            (name+'_ifconfig', '/sbin/ifconfig -a'),

+            (name+'_route', '/sbin/route -n'),

+        ]

 

+    results = collections.defaultdict(str)

+    for (name, host), host_tests in tests.items():

+        results.update(kpov_util.ssh_test(host, 'test', 'test', host_tests))

     return results

 

 def gen_params(user_id, params_meta):

@@ -296,18 +184,18 @@ def task_check(results, params):
         rs = r"tun.*\n.*inet.*{}".format(IP2_C2)

         if re.search(rs, results['VPNClient2_ifconfig']):

             score += 1

-	else:

-	    hints.append("ifconfig on VPNClient2 is not OK")

+        else:

+            hints.append("ifconfig on VPNClient2 is not OK")

             pass

     else:

-	hints.append("ifconfig on VPNClient2 is not OK")

+        hints.append("ifconfig on VPNClient2 is not OK")

         pass

     # C3

     rs = r"tun0.*\n.*inet.*{}".format(IP_C3)

     if re.search(rs, results['VPNClient3_ifconfig']):

         score += 1

     else:

-	hints.append("ifconfig on VPNClient3 is not OK")

+        hints.append("ifconfig on VPNClient3 is not OK")

         pass

     # testi za route

     # C1

@@ -321,22 +209,22 @@ def task_check(results, params):
     if re.search(rs, results['VPNClient1_route']):

         rs = r"{}    {}.*tun0".format(ASD, IP1_C2)

         if re.search(rs, results['VPNClient1_route']):

-	    score += 1

+            score += 1

         else:

             hints.append("route on VPNClient1 is not OK")

     else:

-	hints.append("route on VPNClient1 is not OK")

+        hints.append("route on VPNClient1 is not OK")

         pass

     # C2

     rs = r"{}.*tun".format(IP_C1)

     if re.search(rs, results['VPNClient2_route']):

         rs = r"{}.*tun".format(IP_C3)

         if re.search(rs, results['VPNClient2_route']):

-	    score += 1

+            score += 1

         else:

             hints.append("route on VPNClient2 is not OK")

     else:

-	hints.append("route on VPNClient2 is not OK")

+        hints.append("route on VPNClient2 is not OK")

         pass

     # C3

     rs = r"{}.*tun0".format(IP2_C2)

@@ -349,32 +237,32 @@ def task_check(results, params):
     if re.search(rs, results['VPNClient3_route']):

         rs = r"{}    {}.*tun0".format(ASD, IP2_C2)

         if re.search(rs, results['VPNClient3_route']):

-	    score += 1

+            score += 1

         else:

             hints.append("route on VPNClient3 is not OK")

     else:

-	hints.append("route on VPNClient3 is not OK")

+        hints.append("route on VPNClient3 is not OK")

         pass

     # testi za ping

     # C1

     rs = r"64 bytes from {}: icmp_seq=[0-9]+ ttl=[0-9]+ time=\d+\.\d+ ms".format(IP1_C2)

-    if re.search(rs, results['VPNClient1_ping1_C2']):

-	score += 0.5

+    if re.search(rs, results['VPNClient1_ping_C2']):

+        score += 0.5

     else:

-	hints.append("ping from VPNClient1 to VPNClient2 is not OK")

+        hints.append("ping from VPNClient1 to VPNClient2 is not OK")

         pass

     rs = r"64 bytes from {}: icmp_seq=[0-9]+ ttl=[0-9]+ time=\d+\.\d+ ms".format(IP_C3)

     if re.search(rs, results['VPNClient1_ping_C3']):

-	score += 0.5

+        score += 0.5

     else:

-	hints.append("ping from VPNClient1 to VPNClient3 is not OK")

+        hints.append("ping from VPNClient1 to VPNClient3 is not OK")

         pass

     # C2

     rs = r"64 bytes from {}: icmp_seq=[0-9]+ ttl=[0-9]+ time=\d+\.\d+ ms".format(IP_C1)

     if re.search(rs, results['VPNClient2_ping_C1']):

-	score += 0.5

+        score += 0.5

     else:

-	hints.append("ping from VPNClient2 to VPNClient1 is not OK")

+        hints.append("ping from VPNClient2 to VPNClient1 is not OK")

         pass

     rs = r"64 bytes from {}: icmp_seq=[0-9]+ ttl=[0-9]+ time=\d+\.\d+ ms".format(IP_C3)

     if re.search(rs, results['VPNClient2_ping_C3']):

@@ -385,15 +273,15 @@ def task_check(results, params):
     # C3

     rs = r"64 bytes from {}: icmp_seq=[0-9]+ ttl=[0-9]+ time=\d+\.\d+ ms".format(IP_C1)

     if re.search(rs, results['VPNClient3_ping_C1']):

-	score += 0.5

+        score += 0.5

     else:

-	hints.append("ping from VPNClient3 to VPNClient1 is not OK")

+        hints.append("ping from VPNClient3 to VPNClient1 is not OK")

         pass

     rs = r"64 bytes from {}: icmp_seq=1 ttl=[0-9]+ time=\d+\.\d+ ms".format(IP2_C2)

     if re.search(rs, results['VPNClient3_ping_C2']):

-	score += 0.5

+        score += 0.5

     else:

-	hints.append("ping from VPNClient3 to VPNClient2 is not OK")

+        hints.append("ping from VPNClient3 to VPNClient2 is not OK")

         pass

     #score = int(score)

 

@@ -405,7 +293,7 @@ def task_check(results, params):
         if re.search(rs, results['VPNClient1_traceroute_C3']):

             score += 1

         else:

-	    hints.append("traceroute from VPNClient1 to VPNClient3 is not OK")

+            hints.append("traceroute from VPNClient1 to VPNClient3 is not OK")

             pass

     else:

         hints.append("traceroute from VPNClient1 to VPNClient3 is not OK")

@@ -417,7 +305,7 @@ def task_check(results, params):
         if re.search(rs, results['VPNClient3_traceroute_C1']):

             score += 1

         else:

-	    hints.append("traceroute from VPNClient1 to VPNClient3 is not OK")

+            hints.append("traceroute from VPNClient1 to VPNClient3 is not OK")

             pass

     else:

         hints.append("traceroute from VPNClient1 to VPNClient3 is not OK")

@@ -430,5 +318,3 @@ def task_check(results, params):
 

 def prepare_disks(templates, task_params, global_params):

     write_default_config(templates['simpleArbiterDhcp'], global_params)

-     

-    

diff --git a/kpov_judge/tasks/openvpn_simple_smb/task.py b/kpov_judge/tasks/openvpn_simple_smb/task.py
index 435b40f..fda7a4a 100644
--- a/kpov_judge/tasks/openvpn_simple_smb/task.py
+++ b/kpov_judge/tasks/openvpn_simple_smb/task.py
@@ -102,60 +102,43 @@ params_meta = {
 
 
 def task(IP_SimpleArbiterVPN, IP_VPNClient1, IP_LANClient1, DIRNAME):
-     
+    import collections
     from pexpect import pxssh    # Used to set up an SSH connection to a remote machine
     import pexpect  # Allows the script to spawn a child application and control it as if a human were typing commands
-    
-    
+
     # The necessary things we need to check if the task was performed correctly
-    results = dict()
+    results = collections.defaultdict(str)
     
-    # The login params (these must be used on the machines!)
-    peer_user = 'student'
-    peer_passwd = 'vaje'
-   
-    ###
-    # Sets up the SSH connections to the machines
-    ###
     # VPNClient1
-    sC1 = pxssh.pxssh()
-    
-    # Logs in to the machines with the default login params
-    sC1.login(
-        IP_LANClient1,
-        peer_user,
-        peer_passwd
-    )
+    sC1 = pxssh.pxssh(encoding='utf-8')
+    sC1.login(IP_LANClient1, 'student', 'vaje')
     
-    ######
     # sA
-    ######
-    
     results['SimpleArbiter_ifconfig'] = pexpect.run(
-        '/sbin/ifconfig -a')
-    
+        'ifconfig -a', encoding='utf-8', env={'PATH': '/bin:/sbin'})
     results['SimpleArbiter_route'] = pexpect.run(
-        '/sbin/route -n')
+        'route -n', encoding='utf-8', env={'PATH': '/bin:/sbin'})
     
     # Pings each of the clients
     # 10.8.0.6 and 10.8.0.10 are the first two default addresses distributed by OpenVPN
     # Will output everything ping outputs (set to ping 3 times)
     results['SimpleArbiter_ping_C1'] = pexpect.run(
-        'ping -c 3 {}'.format(IP_VPNClient1))
+        'ping -c 3 {}'.format(IP_VPNClient1), encoding='utf-8')
     results['SimpleArbiter_traceroute'] = pexpect.run(
-        '/usr/bin/traceroute {}'.format(IP_VPNClient1))
+        'traceroute {}'.format(IP_VPNClient1), encoding='utf-8')
     sC1.sendline('cat /etc/exports')
     sC1.prompt()
     output = sC1.before
     results['VPNClient1_nfs_access_control_list'] = output
     results['SimpleArbiter_mount'] = pexpect.run(
-        'sudo mount {}:/home/test/{} /mnt'.format(IP_VPNClient1, DIRNAME))
+        'sudo mount {}:/home/test/{} /mnt'.format(IP_VPNClient1, DIRNAME), encoding='utf-8')
     results['SimpleArbiter_mount_result'] = pexpect.run(
-        'sudo mount')
+        'sudo mount', encoding='utf-8')
     results['SimpleArbiter_ls'] = pexpect.run(
-        'ls /mnt')
+        'ls /mnt', encoding='utf-8')
     pexpect.run(
-        'sudo umount /mnt')
+        'sudo umount /mnt', encoding='utf-8')
+
     # Ping the VPN server
     sC1.sendline('ping -c 3 {0}'.format( IP_SimpleArbiterVPN ))
     sC1.prompt()
@@ -169,10 +152,8 @@ def task(IP_SimpleArbiterVPN, IP_VPNClient1, IP_LANClient1, DIRNAME):
     sC1.prompt()
     results['VPNClient1_ps'] = sC1.before
     sC1.logout()
-    
-    
-    return results
 
+    return results
 
 def gen_params(user_id, params_meta):
     params = dict()
@@ -189,64 +170,46 @@ def gen_params(user_id, params_meta):
 
 
 def task_check(results, params):
-    
     import re
     score = 0
     hints = [] 
-    # zal si se nisem prišla na jasno s pingi
+
     IP_SA = params['IP_SimpleArbiterVPN'].replace('.', '\.')
     IP_C1 = params['IP_VPNClient1'].replace('.', '\.')
-    rs = r"tap0: flags=.* mtu 1500\r\n +inet {}".format(
-        IP_SA)
-    # print rs, re.match(rs, results['SimpleArbiter_ifconfig'])
+    rs = r"tap0: flags=.* mtu 1500\r\n +inet {}".format(IP_SA)
     if re.search(rs,
             results['SimpleArbiter_ifconfig']):
         score += 1
-    #    print "ifconfig OK"
     else:
         hints.append("ifconfig on SimpleArbiter not OK")
-        pass
-    #    print ('SA_ifconfig', results['SimpleArbiter_ifconfig'])
-    # results['SimpleArbiter_route'] = pexpect.run(
     
     if re.search(
-        "PING.*\r\n64 bytes from {}: icmp_seq=[0-9]+ ttl=64 time=[0-9.]* ms".format(
-                IP_C1),
+            "PING.*\r\n64 bytes from {}: icmp_seq=[0-9]+ ttl=64 time=[0-9.]* ms".format(IP_C1),
             results['SimpleArbiter_ping_C1']):
-    #    print "Server ping OK"
         score += 1
     else:
         hints.append("ping from server not OK")
-        pass
-    #    print ("Server ping", results['SimpleArbiter_ping_C1'])
-    # ignore this
-    # print results['SimpleArbiter_mount']
-    # print results['SimpleArbiter_traceroute']
     rs = "1 +{0} \({0}\)".format(IP_C1)
-    if re.search(rs,
-        results['SimpleArbiter_traceroute']):
+    if re.search(rs, results['SimpleArbiter_traceroute']):
         score += 1
     else:
         hints.append("traceroute not OK")
-        pass
-    #    print ("fail!", rs, results['SimpleArbiter_traceroute'])
     if results['VPNClient1_nfs_access_control_list'].find(
         '/home/test/' + params['DIRNAME'] + ' ') >= 0:
         score += 1
     if results['SimpleArbiter_mount_result'].find(
-        '{}:/home/test/{} on /mnt type nfs'.format(
-            params['IP_VPNClient1'],
-            params['DIRNAME'])):
-    #    print "mount OK"
+            '{}:/home/test/{} on /mnt type nfs'.format(
+            params['IP_VPNClient1'], params['DIRNAME'])):
         score += 1
     else:
         hints.append("mount not OK")
+
     # get r into the correct state
     r = random.Random(params['secret_random_seed'])
-    s = "\n".join([
-        "".join([r.choice("0123456789abcdef") for i in range(32)])
+    s = "\n".join(["".join([r.choice("0123456789abcdef") for i in range(32)])
         for i in range(16)])
     keyfile = kpov_util.fname_gen(r, extension=False)
+
     # now check the filenames
     fnames_ok = True
     for i in range(3):
@@ -254,34 +217,24 @@ def task_check(results, params):
         foo = kpov_util.fortune(r, 4096)
         pos = results['SimpleArbiter_ls'].find(fname + '.txt')
         fnames_ok = fnames_ok and pos >= 0
-        #if pos < 0:
-        #    hints.append("missing file:" + fname)
     if fnames_ok:
         score += 2
     else:
         hints.append("shared filenames not OK:")
+
     # Ping the VPN server
     if re.search(
-        "PING.*\r\n64 bytes from {}: icmp_seq=[0-9]+ ttl=64 time=[0-9.]* ms".format(
-                IP_SA), 
+            "PING.*\r\n64 bytes from {}: icmp_seq=[0-9]+ ttl=64 time=[0-9.]* ms".format(IP_SA), 
             results['VPNClient1_ping_VPN_server']):
-    #    print "ping OK"
         score += 1
     else:
         hints.append("ping from client not OK")
-        pass
-    #    print "Client ping", results['VPNClient1_ping_VPN_server']
 
-    rs = r"tap0: flags=.* mtu 1500\r\n +inet {}".format(
-        IP_C1)
-    if re.search(rs,
-            results['VPNClient1_ifconfig']):
+    rs = r"tap0: flags=.* mtu 1500\r\n +inet {}".format(IP_C1)
+    if re.search(rs, results['VPNClient1_ifconfig']):
         score += 1
-    #    print "ifconfig OK"
     else:
         hints.append("ifconfig on VPNClient1 not OK")
-        pass
-    #    print ('VPNClient1_ifconfig', results['VPNClient1_ifconfig'])
  
     if results['VPNClient1_ps'].find('openvpn') > 0:
         score += 1
@@ -289,11 +242,7 @@ def task_check(results, params):
         hints.append("openvpn not found running on VPNClient")
     return score, hints
 
-
 def prepare_disks(templates, task_params, global_params):
-    
-    #d = templates['simpleArbiterDhcp']
-    
     #guestmount -a d -m /dev/VG/LV -m /dev/sda1:/boot --ro /mnt
     #asistent je pocasnela :) 
     import random
@@ -327,6 +276,3 @@ iface tap0 inet static
     templates['student-VPNClient1'].write("/home/student/" + keyfile, s)
     # uid, gid (student = )
     templates['student-VPNClient1'].chown(1000, 1000, "/home/student/" + keyfile) 
-     
-    
-
diff --git a/kpov_judge/tasks/openwrt/task.py b/kpov_judge/tasks/openwrt/task.py
index b55905c..98f1420 100644
--- a/kpov_judge/tasks/openwrt/task.py
+++ b/kpov_judge/tasks/openwrt/task.py
@@ -18,10 +18,6 @@ computers = {
         'disks': [
             {   'name': 'maliNetworkManager',
             },
-            #{   'name': 'CDROM',
-            #    'options':{'readonly': True},
-            #    'parts': [],# no parts, no mounting.
-            #}
         ],
         'network_interfaces': [{'network': 'net1'}],
         'flavor': 'm1.tiny',
@@ -32,10 +28,6 @@ computers = {
         'disks': [
             {   'name': 'maliBrezNetworkManager',
             },
-            #{   'name': 'CDROM',
-            #    'options':{'readonly': True},
-            #    'parts': [],# no parts, no mounting.
-            #}
         ],
         'network_interfaces': [{'network': 'net1'}],
         'flavor': 'm1.tiny',
@@ -45,12 +37,7 @@ computers = {
     'SimpleArbiter': {
         'disks': [
             {   'name': 'simpleArbiterDhcp',
-                # attempt automount
             },
-            #{   'name': 'CDROM',
-            #    'options': {'readonly': True},
-            #    'parts': [{'dev': 'b1', 'path': '/cdrom'}],
-            #},
         ],
         'network_interfaces': [{'network': 'net1'}, {'network': 'test-net'}],
         'flavor': 'm1.tiny',
diff --git a/kpov_judge/tasks/radius_mysql_pam/task.py b/kpov_judge/tasks/radius_mysql_pam/task.py
index 1a11ef8..be99e6a 100644
--- a/kpov_judge/tasks/radius_mysql_pam/task.py
+++ b/kpov_judge/tasks/radius_mysql_pam/task.py
@@ -58,10 +58,6 @@ computers = {
         'disks': [
             {   'name': 'student-RadiusServer',
             },
-            #{   'name': 'CDROM',
-            #    'options':{'readonly': True},
-            #    'parts': [],# no parts, no mounting.
-            #}
         ],
         'network_interfaces': [{'network': 'net1'}],
         'flavor': 'm1.tiny',
@@ -71,12 +67,7 @@ computers = {
     'SimpleArbiter': {
         'disks': [
             {   'name': 'simpleArbiterDhcpGW',
-                # attempt automount
             },
-            #{   'name': 'CDROM',
-            #    'options': {'readonly': True},
-            #    'parts': [{'dev': 'b1', 'path': '/cdrom'}],
-            #},
         ],
         'network_interfaces': [{'network': 'net1'}, {'network': 'test-net'}],
         'flavor': 'm1.tiny',
@@ -97,20 +88,23 @@ params_meta = {
     'MYSQL_SEED':{'descriptions': {'si': 'seed', 'en': 'seed'}, 'w': False, 'public':True, 'type': None, 'generated': True},
 }
 
-def task(IP_RS, RADIUS_SECRET, RADIUS_USERNAME, RADIUS_PASSWORD, MYSQL_DB_NAME, MYSQL_ADMIN_USER, MYSQL_ADMIN_PASSWORD, MYSQL_SEED):
-    from pexpect import pxssh
-    import pexpect
+def task(IP_RS, RADIUS_SECRET, RADIUS_USERNAME, RADIUS_PASSWORD,
+         MYSQL_DB_NAME, MYSQL_ADMIN_USER, MYSQL_ADMIN_PASSWORD, MYSQL_SEED):
+    import collections
     import random
-    results = dict()
-    peer_user = 'student'
-    peer_passwd = 'vaje'
+    import pexpect
+
     r = random.Random(MYSQL_SEED)
     MYSQL_TEST_USER = kpov_util.username_gen(r)
     MYSQL_TEST_PASSWORD = kpov_util.alnum_gen(r, 7)
     RADIUS_NEW_PASSWORD = kpov_util.alnum_gen(r, 7)
-    # Testiranje radius strtežnika
+
+    results = collections.defaultdict(str)
+
+    # Testiranje radius strežnika
     results['Test_RadiusServer'] = pexpect.run('radtest {0} {1} {2} 1812 {3}'.format(
         RADIUS_USERNAME, RADIUS_PASSWORD, IP_RS, RADIUS_SECRET))
+
     # Testiranje podatkovne base mysql
     mysql = pexpect.spawn('mysql -u {MYSQL_ADMIN_USER} -p{MYSQL_ADMIN_PASSWORD} -h {IP_RS}'.format(**locals()))
     mysql.expect("mysql>")
@@ -123,22 +117,25 @@ def task(IP_RS, RADIUS_SECRET, RADIUS_USERNAME, RADIUS_PASSWORD, MYSQL_DB_NAME,
     results['select_from_users'] = mysql.before
     mysql.sendline("INSERT INTO radcheck (UserName, Attribute, Value, Op) VALUES ('{MYSQL_TEST_USER}', 'Cleartext-Password', '{MYSQL_TEST_PASSWORD}', ':=');".format(**locals()))
     mysql.expect("mysql>")
+
     results['radtest_OK'] = pexpect.run('radtest {0} {1} {2} 1812 {3}'.format(
         MYSQL_TEST_USER, MYSQL_TEST_PASSWORD, IP_RS, RADIUS_SECRET))
     results['radtest_NOK'] = pexpect.run('radtest {0} {1} {2} 1812 {3}'.format(
         MYSQL_TEST_USER, "Flügzeug", IP_RS, RADIUS_SECRET))
     results['radtest_NOK'] = pexpect.run('radtest {0} {1} {2} 1812 {3}'.format(
         MYSQL_TEST_USER, "Flügzeug", IP_RS, RADIUS_SECRET))
-    sT = pxssh.pxssh()
+
     mysql.sendline("UPDATE radcheck SET value='{RADIUS_NEW_PASSWORD}' where UserName='{RADIUS_USERNAME}' and Attribute='Cleartext-Password';".format(**locals()))
-    sT.login(IP_RS, RADIUS_USERNAME, RADIUS_NEW_PASSWORD)
-    results['login_test'] = sT.before
+
+    results.update(kpov_util.ssh_test(IP_RS, RADIUS_USERNAME, RADIUS_NEW_PASSWORD))
+
     mysql.sendline("UPDATE radcheck SET value='{RADIUS_PASSWORD}' where UserName='{RADIUS_USERNAME}' and Attribute='Cleartext-Password';".format(**locals()))
     mysql.expect('mysql>')
     mysql.sendline("DELETE FROM radcheck where UserName='{MYSQL_TEST_USER}' and Attribute='Cleartext-Password';".format(**locals()))
     mysql.expect('mysql>')
     mysql.sendline('\q');
-    # Testiranje PAM s testnim uporabnikom
+    # TODO Testiranje PAM s testnim uporabnikom
+
     return results
     
 def gen_params(user_id, params_meta):
@@ -209,8 +206,8 @@ def task_check(results, params):
     else:
         hints.append('radtest negative output incorrect: ' + results['radtest_NOK'])
         print((results['radtest_NOK'], s))
-    s = "{RADIUS_USERNAME}@.*:~\\$".format(**params)
-    if re.search(s, results['login_test'], flags=re.DOTALL):
+    s = "{RADIUS_USERNAME}@.*:".format(**params)
+    if re.search(s, results['motd'], flags=re.DOTALL):
         # print "login_test OK"
         score += 1
     else:
@@ -220,4 +217,3 @@ def task_check(results, params):
 
 def prepare_disks(templates, task_params, global_params):
     write_default_config(templates['simpleArbiterDhcpGW'], global_params)
-
diff --git a/kpov_judge/tasks/rename_grep_network/task.py b/kpov_judge/tasks/rename_grep_network/task.py
index cba9ac9..c1be010 100644
--- a/kpov_judge/tasks/rename_grep_network/task.py
+++ b/kpov_judge/tasks/rename_grep_network/task.py
@@ -152,30 +152,12 @@ params_meta = {
 }
 
 def task(testip, testuser, passwd, mntdir, magicstr):
-    import collections
-    from pexpect import pxssh
-
-    commands = [
+    return kpov_util.ssh_test(testip, testuser, passwd, (
         ('home_ls', 'ls ~/'),
         ('dst_file_contents', 'cat ~/*I*.txt'),
         ('dst_ls', 'ls -l ~/*I*.txt'),
         ('mnt', 'mount'),
-    ]
-
-    results = collections.defaultdict(str)
-    try:
-        s = pxssh.pxssh(encoding='utf-8')
-        s.login(testip, testuser, passwd)
-        results['ssh'] = True
-        for test, command in commands:
-            s.sendline(command)
-            s.prompt()
-            if test:
-                results[test] = s.before
-        s.logout()
-    except Exception as ex:
-        results['ssh'] = str(ex)
-    return results
+    ))
 
 def gen_params(user_id, params_meta):
     import random
@@ -216,7 +198,6 @@ def task_check(results, params):
     #                           r"pokakalz\r", 
     #                           hidden_contents, 
     #                           re.MULTILINE)
-    expected_contents = "cat ~/*I*.txt\r\n".format(dstfile) + expected_contents
     if results["dst_file_contents"] == expected_contents:
         score += 3
     else:
@@ -228,9 +209,8 @@ def task_check(results, params):
                 diff_pos = (i, results["dst_file_contents"][start:end])
                 break
         hints += ["wrong file contents\n" + str(diff_pos[1])]
-        #hints += ["wrong file contents"]
     params['dstfile'] = dstfile
-    expected_dst_ls = "ls -l ~/\\*I\\*.txt\r\n-rw--w---- 1 {testuser} bilbo .*{dstfile}\r\n".format(**params)
+    expected_dst_ls = "-rw--w---- 1 {testuser} bilbo .*{dstfile}".format(**params)
     if re.match(expected_dst_ls, results["dst_ls"]):
         score += 2
     else:
@@ -253,10 +233,7 @@ def task_check(results, params):
 def prepare_disks(templates, task_params, global_params):
     import random
     import os
-    #print "Haha!"
-    #print params
-    #print templates
-    d = templates['smallstudent-personal']
+
     # first create the file contents to make it easyer to check.
     hidden_contents = task_params['magicstr']
     r = random.Random(task_params['rndseed'])
@@ -266,6 +243,7 @@ def prepare_disks(templates, task_params, global_params):
         x += "".join([r.choice("uiasdfghjkyxcvbnm1234567890ASDFGHJKYZXCVBNM") for i in range(60)])
         x += r.choice(["lz", "1z", "Iz", "iz", "l2", "I2", "12"])
         hidden_contents += x + "\n"
+
     # create hidden file
     dir_list = ['Qlipper', 'Thunar', 'blender', 'autostart', 'kazam', 'mc', 'netsurf', 'pulse', 'qupzilla', 'radare2', 'teamviewer', 'texstudio', 'vlc']
     ending_list = ['rc', '.conf', '', '.txt']
@@ -274,6 +252,8 @@ def prepare_disks(templates, task_params, global_params):
         start_list.append("".join([r.choice("qQoOp") for i in range(64)]) + "O")
     r.shuffle(dir_list)
     file_letters = ["mod", "co"]
+
+    d = templates['smallstudent-personal']
     d.mkdir('/mnt/.hideme')
     d.mkdir('/media/.hideme')
     for potential_dir in dir_list:
@@ -304,6 +284,3 @@ def prepare_disks(templates, task_params, global_params):
     # TODO create some additional files 
     
     # write_default_config(templates['simpleArbiterDhcpGW'], global_params)
-    # finish here
-    # rename
-
diff --git a/kpov_judge/tasks/set_ip_static_dhcp/task.py b/kpov_judge/tasks/set_ip_static_dhcp/task.py
index 4cdbc14..3a3fcc6 100644
--- a/kpov_judge/tasks/set_ip_static_dhcp/task.py
+++ b/kpov_judge/tasks/set_ip_static_dhcp/task.py
@@ -85,23 +85,17 @@ params_meta = {
 
 def task(IP_NM, DNS_NM, IP_static, DNS_static):
     import collections
-    from pexpect import pxssh
 
-    tests = ['nmcli -c no d', 'nslookup www.arnes.si']
-    results = collections.defaultdict(str)
+    tests = (
+        ('nmcli', 'nmcli -c no d'),
+        ('nslookup', 'nslookup www.arnes.si'),
+    )
 
+    results = collections.defaultdict(str)
     for name, host in [('nm', IP_NM), ('static', IP_static)]:
-        try:
-            s = pxssh.pxssh(encoding='utf-8')
-            s.login(host, 'student', 'vaje')
-            results['ssh-'+name] = True
-            for test in tests:
-                s.sendline(test)
-                s.prompt()
-                results[test.split()[0]+'-'+name] = s.before
-            s.logout()
-        except Exception as ex:
-            results['ssh'] = str(ex)
+        host_results = kpov_util.ssh_test(host, 'student', 'vaje', tests)
+        for key, value in host_results.items():
+            results[key+'-'+name] = value
     return results
     
 def gen_params(user_id, params_meta):
diff --git a/kpov_judge/tasks/set_motd/task.py b/kpov_judge/tasks/set_motd/task.py
index 956f570..5f1b0b3 100644
--- a/kpov_judge/tasks/set_motd/task.py
+++ b/kpov_judge/tasks/set_motd/task.py
@@ -76,20 +76,7 @@ params_meta = {
 
 def task(peer_ip, peer_user, peer_passwd, niz):
     "Check whether ssh works"
-    import collections
-    from pexpect import pxssh
-    results = collections.defaultdict(str)
-    try:
-        s = pxssh.pxssh(encoding='utf-8')
-        s.login(peer_ip, peer_user, peer_passwd,
-                original_prompt=r'{0}@.*:\~\$'.format(peer_user),
-                auto_prompt_reset=False)
-        results['ssh'] = True
-        results['motd'] = s.before
-        s.logout()
-    except Exception as ex:
-        results['ssh'] = str(ex)
-    return results
+    return kpov_util.ssh_test(peer_ip, peer_user, peer_passwd)
 
 def gen_params(user_id, params_meta):
     return kpov_util.default_gen(user_id, params_meta)
diff --git a/kpov_judge/tasks/vlc_stream_rtp/task.py b/kpov_judge/tasks/vlc_stream_rtp/task.py
index 7948e51..2e731f2 100644
--- a/kpov_judge/tasks/vlc_stream_rtp/task.py
+++ b/kpov_judge/tasks/vlc_stream_rtp/task.py
@@ -79,7 +79,6 @@ def task(NASLOV, TOK):
     results['ps'] = pexpect.run('ps xa')
     results['tcpdump_hex'] = pexpect.run('sudo /usr/sbin/tcpdump -x -c 2 dst host 239.255.255.255 and port 9875'.format(NASLOV))
     results['tcpdump'] = pexpect.run('sudo /usr/sbin/tcpdump -c 8 dst host {}'.format(NASLOV))
-    # print("HAHA")
     return results
     
 def gen_params(user_id, params_meta):