some small linting fixes (#1351)

* small linting fixes for new version of flake8
* format string fix
* expand single letter variable names

src/cowrie/commands/base.py

@@ -532,8 +532,8 @@ class command_shutdown(HoneyPotCommand):
                 "-t secs: delay between warning and kill signal. ",
                 "** the \"time\" argument is mandatory! (try \"now\") **",
             )
-            for l in output:
-                self.write('{0}\n'.format(l))
+            for line in output:
+                self.write('{0}\n'.format(line))
             self.exit()
         elif len(self.args) > 1 and self.args[0].strip().count('-h') \
                 and self.args[1].strip().count('now'):
@@ -595,8 +595,8 @@ class command_history(HoneyPotCommand):
                 self.protocol.historyPosition = 0
                 return
             count = 1
-            for l in self.protocol.historyLines:
-                self.write(' %s  %s\n' % (str(count).rjust(4), l))
+            for line in self.protocol.historyLines:
+                self.write(' %s  %s\n' % (str(count).rjust(4), line))
                 count += 1
         except Exception:
             # Non-interactive shell, do nothing
@@ -701,8 +701,8 @@ class command_php(HoneyPotCommand):
                 'PHP 5.3.5 (cli)',
                 'Copyright (c) 1997-2010 The PHP Group'
             )
-            for l in output:
-                self.write('{0}\n'.format(l))
+            for line in output:
+                self.write('{0}\n'.format(line))
             self.exit()
         elif self.args[0] == '-h':
             output = (
@@ -745,8 +745,8 @@ class command_php(HoneyPotCommand):
                 '  --ri <name>      Show configuration for extension <name>.',
                 ''
             )
-            for l in output:
-                self.write('{0}\n'.format(l))
+            for line in output:
+                self.write('{0}\n'.format(line))
             self.exit()
         else:
             self.exit()

src/cowrie/commands/chpasswd.py

@@ -33,8 +33,8 @@ class command_chpasswd(HoneyPotCommand):
             '  -s, --sha-rounds              number of SHA rounds for the SHA*'
             '                                crypt algorithms'
         )
-        for l in output:
-            self.write(l + '\n')
+        for line in output:
+            self.write(line + '\n')
 
     def chpasswd_application(self, contents):
         c = 1

src/cowrie/commands/crontab.py

@@ -29,8 +29,8 @@ class command_crontab(HoneyPotCommand):
             '          -r      (delete user\'s crontab)',
             '          -i      (prompt before deleting user\'s crontab)'
         )
-        for l in output:
-            self.write(l + '\n')
+        for line in output:
+            self.write(line + '\n')
 
     def start(self):
         try:

src/cowrie/commands/curl.py

@@ -408,9 +408,8 @@ class HTTPProgressDownloader(client.HTTPDownloader):
 
         if self.fakeoutfile:
             self.curl.write(
-                "\r100  {}  100  {}    0     0  {}      0 --:--:-- --:--:-- --:--:-- %d\n".format(self.currentlength,
-                                                                                                  self.currentlength,
-                                                                                                  63673, 65181))
+                "\r100  {}  100  {}    0     0  {}      0 --:--:-- --:--:-- --:--:-- {}\n".format(
+                  self.currentlength, self.currentlength, 63673, 65181))
 
             self.curl.fs.mkfile(self.fakeoutfile, 0, 0, self.totallength, 33188)
             self.curl.fs.update_realfile(

src/cowrie/commands/gcc.py

@@ -165,7 +165,7 @@ COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.7/lto-wrapper
 Target: x86_64-linux-gnu
 Configured with: ../src/configure -v --with-pkgversion=\'Debian {}-5\' --with-bugurl=file:///usr/share/doc/gcc-{}/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-{} --enable-shared --enable-multiarch --enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/{} --libdir=/usr/lib --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug --enable-objc-gc --with-arch-32=i586 --with-tune=generic --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
 Thread model: posix
-gcc version %s (Debian {}-5)""".format(version, version_short, version_short, version_short, version, version))  # noqa: E501
+gcc version {} (Debian {}-5)""".format(version, version_short, version_short, version_short, version, version))  # noqa: E501
 
         # Write
         self.write('{0}\n'.format(data))

src/cowrie/commands/perl.py

@@ -33,8 +33,8 @@ class command_perl(HoneyPotCommand):
             'Internet, point your browser at http://www.perl.org/, the Perl Home Page.',
             ''
         )
-        for l in output:
-            self.write(l + '\n')
+        for line in output:
+            self.write(line + '\n')
 
     def help(self):
         output = (
@@ -70,8 +70,8 @@ class command_perl(HoneyPotCommand):
             '  -X                disable all warnings',
             ''
         )
-        for l in output:
-            self.write(l + '\n')
+        for line in output:
+            self.write(line + '\n')
 
     def start(self):
         try:

src/cowrie/commands/ping.py

@@ -49,13 +49,13 @@ class command_ping(HoneyPotCommand):
                     return
 
         if len(args) == 0:
-            for l in (
+            for line in (
                     'Usage: ping [-LRUbdfnqrvVaA] [-c count] [-i interval] [-w deadline]',
                     '            [-p pattern] [-s packetsize] [-t ttl] [-I interface or address]',
                     '            [-M mtu discovery hint] [-S sndbuf]',
                     '            [ -T timestamp option ] [ -Q tos ] [hop1 ...] destination',
             ):
-                self.write('{0}\n'.format(l))
+                self.write('{0}\n'.format(line))
             self.exit()
             return
         self.host = args[0].strip()

src/cowrie/commands/python.py

@@ -69,8 +69,8 @@ class command_python(HoneyPotCommand):
             '   str, bytes and datetime objects.  It can also be set to an integer',
             '   in the range [0,4294967295] to get hash values with a predictable seed.'
         )
-        for l in output:
-            self.write(l + '\n')
+        for line in output:
+            self.write(line + '\n')
 
     def start(self):
         try:

src/cowrie/commands/service.py

@@ -82,8 +82,8 @@ class command_service(HoneyPotCommand):
             '[ - ]  uuidd',
             '[ + ]  whoopsie',
             '[ - ]  x11-common')
-        for l in output:
-            self.write(l + '\n')
+        for line in output:
+            self.write(line + '\n')
 
     def help(self):
         output = 'Usage: service < option > | --status-all | [ service_name [ command | --full-restart ] ]'

src/cowrie/commands/ssh.py

@@ -52,8 +52,8 @@ class command_ssh(HoneyPotCommand):
                 self.exit()
                 return
         if not len(args):
-            for l in OUTPUT:
-                self.write('{0}\n'.format(l))
+            for line in OUTPUT:
+                self.write('{0}\n'.format(line))
             self.exit()
             return
         user, host = 'root', args[0]

src/cowrie/commands/tar.py

@@ -73,7 +73,7 @@ class command_tar(HoneyPotCommand):
                 self.mkfullpath(os.path.dirname(dest), f)
                 self.fs.mkfile(dest, 0, 0, f.size, f.mode, f.mtime)
             else:
-                log.msg("tar: skipping [%s]".format(f.name))
+                log.msg("tar: skipping [{}]".format(f.name))
 
 
 commands['/bin/tar'] = command_tar

src/cowrie/output/kafka.py

@@ -48,8 +48,8 @@ import cowrie.core.output
 import cowrie.python.logfile
 
 
-def random_string(l, charset=string.letters.encode()):
-    return b"".join(random.choice(charset) for i in range(l))
+def random_string(length, charset=string.letters.encode()):
+    return b"".join(random.choice(charset) for i in range(length))
 
 
 def make_messages():

src/cowrie/output/virustotal.py

@@ -207,7 +207,7 @@ class Output(cowrie.core.output.Output):
             elif j['response_code'] == -2:
                 log.msg("VT: response=-2: this has been queued for analysis already")
             else:
-                log.msg("VT: unexpected response code".format(j['response_code']))
+                log.msg("VT: unexpected response code: {}".format(j['response_code']))
 
         d.addCallback(cbResponse)
         d.addErrback(cbError)
@@ -354,7 +354,7 @@ class Output(cowrie.core.output.Output):
                 log.msg("VT: response=1: this has been queued for analysis already")
                 log.msg("VT: permalink: {}".format(j['permalink']))
             else:
-                log.msg("VT: unexpected response code".format(j['response_code']))
+                log.msg("VT: unexpected response code: {}".format(j['response_code']))
 
         d.addCallback(cbResponse)
         d.addErrback(cbError)

src/cowrie/shell/shlex.py

@@ -105,7 +105,7 @@ class shlex:
         self.instream.close()
         (self.infile, self.instream, self.lineno) = self.filestack.popleft()
         if self.debug:
-            print('shlex: popping to {}, line %d'.format(self.instream, self.lineno))
+            print('shlex: popping to {}, line {}'.format(self.instream, self.lineno))
         self.state = ' '
 
     def get_token(self):