diff --git a/twisted/scripts/tap2rpm.py b/twisted/scripts/tap2rpm.py
index f3d2e0d..e531257 100755
--- a/twisted/scripts/tap2rpm.py
+++ b/twisted/scripts/tap2rpm.py
@@ -10,7 +10,6 @@ import tarfile
 from StringIO import StringIO
 
 from twisted.python import usage, log
-from twisted.scripts import tap2deb
 
 
 #################################
@@ -95,7 +94,7 @@ Release:    1
 License:    Unknown
 Group:      Networking/Daemons
 Source:     %(tarfile_basename)s
-BuildRoot:  /var/tmp/%%{name}-%%{version}-root
+BuildRoot:  %%{_tmppath}/%%{name}-%%{version}-root
 Requires:   /usr/bin/twistd
 BuildArch:  noarch
 
@@ -143,10 +142,11 @@ class MyOptions(usage.Options):
     optFlags = [["unsigned", "u"], ['quiet', 'q']]
     optParameters = [
                      ["tapfile", "t", "twistd.tap"],
-                     ["maintainer", "m", ""],
-                     ["protocol", "p", ""],
-                     ["description", "e", ""],
-                     ["long_description", "l", ""],
+                     ["maintainer", "m", "tap2rpm"],
+                     ["protocol", "p", None],
+                     ["description", "e", None],
+                     ["long_description", "l",
+                         "Automatically created by tap2rpm"],
                      ["set-version", "V", "1.0"],
                      ["rpmfile", "r", None],
                      ["type", "y", "tap", "type of configuration: 'tap', 'xml, "
@@ -160,6 +160,25 @@ class MyOptions(usage.Options):
                    "rpmfile":'_files -g "*.rpm"'}
     #zsh_actionDescr = {"logfile":"log file name", "random":"random seed"}
 
+    def postOptions(self):
+        """
+        Calculate the default values for certain command-line options.
+        """
+        # Options whose defaults depend on other parameters.
+        if self['protocol'] is None:
+            base_tapfile = os.path.basename(self['tapfile'])
+            self['protocol'] = os.path.splitext(base_tapfile)[0]
+        if self['description'] is None:
+            self['description'] = "A TCP server for %s" % (self['protocol'],)
+        if self['rpmfile'] is None:
+            self['rpmfile'] = 'twisted-%s' % (self['protocol'],)
+
+        # Values that aren't options, but are calculated from options and are
+        # handy to have around.
+        self['twistd_option'] = type_dict[self['type']]
+        self['release-name'] = '%s-%s' % (self['rpmfile'], self['set-version'])
+
+
 
 type_dict = {
     'tap': 'file',
@@ -169,8 +188,9 @@ type_dict = {
 }
 
 
+
 ##########################
-def makeBuildDir(baseDir):
+def makeBuildDir():
     '''
     Set up the temporary directory for building RPMs.
 
@@ -186,105 +206,107 @@ def makeBuildDir(baseDir):
     os.makedirs(os.path.join(tmpDir, 'SOURCES'))
     os.makedirs(os.path.join(tmpDir, 'SRPMS'))
 
+    log.msg(format="Created RPM build structure in %(path)r",
+            path=tmpDir)
     return tmpDir
 
 
-##########
-def run(options=None):
-    #  parse options
-    try:
-        config = MyOptions()
-        config.parseOptions(options)
-    except usage.error, ue:
-         sys.exit("%s: %s" % (sys.argv[0], ue))
 
-    #  set up some useful local variables
-    tap_file = config['tapfile']
-    base_tap_file = os.path.basename(config['tapfile'])
-    protocol = (config['protocol'] or os.path.splitext(base_tap_file)[0])
-    rpm_file = config['rpmfile'] or 'twisted-'+protocol
-    version = config['set-version']
-    maintainer = config['maintainer']
-    description = config['description'] or ('A TCP server for %(protocol)s' %
-                                            vars())
-    long_description = (config['long_description']
-                        or "Automatically created by tap2rpm")
-    twistd_option = type_dict[config['type']]
-    date = time.strftime('%a %b %d %Y', time.localtime(time.time()))
-    directory = rpm_file + '-' + version
-    python_version = '%s.%s' % sys.version_info[:2]
-
-    #  set up a blank maintainer if not present
-    if not maintainer:
-        maintainer = 'tap2rpm'
-
-    #  create source archive directory
-    tmp_dir = makeBuildDir('/var/tmp')
-    source_dir = os.path.join(tmp_dir, directory)
-    os.makedirs(source_dir)
-
-    #  create source tar
-    tarfile_name = source_dir + '.tar.gz'
-    tarfile_basename = os.path.basename(tarfile_name)
-    tarHandle = tarfile.open(tarfile_name, "w:gz")
-
-    sourceDirInfo = tarfile.TarInfo(directory)
+def setupBuildFiles(buildDir, config):
+    """
+    Create files required to build an RPM in the build directory.
+    """
+    # Create the source tarball in the SOURCES directory.
+    tarballName = "%s.tar" % (config['release-name'],)
+    tarballPath = os.path.join(buildDir, "SOURCES", tarballName)
+    tarballHandle = tarfile.open(tarballPath, "w")
+
+    sourceDirInfo = tarfile.TarInfo(config['release-name'])
     sourceDirInfo.type = tarfile.DIRTYPE
     sourceDirInfo.mode = 0755
-    tarHandle.addfile(sourceDirInfo)
+    tarballHandle.addfile(sourceDirInfo)
 
-    specFileInfo = tarfile.TarInfo(
-            os.path.join(directory, '%s.spec' % rpm_file))
-    specFileInfo.type = tarfile.REGTYPE
-    specFileInfo.mode = 0644
-    specFileRealData = specFileData % vars()
-    specFileInfo.size = len(specFileRealData)
-    tarHandle.addfile(specFileInfo, StringIO(specFileRealData))
+    tapFileBase = os.path.basename(config['tapfile'])
 
     initFileInfo = tarfile.TarInfo(
-            os.path.join(directory, '%s.init' % rpm_file))
+            os.path.join(
+                config['release-name'],
+                '%s.init' % config['rpmfile'],
+            )
+        )
     initFileInfo.type = tarfile.REGTYPE
     initFileInfo.mode = 0755
-    initFileRealData = initFileData % vars()
+    initFileRealData = initFileData % {
+            'tap_file': tapFileBase,
+            'rpm_file': config['release-name'],
+            'twistd_option': config['twistd_option'],
+        }
     initFileInfo.size = len(initFileRealData)
-    tarHandle.addfile(initFileInfo, StringIO(initFileRealData))
+    tarballHandle.addfile(initFileInfo, StringIO(initFileRealData))
 
-    tapFileHandle = open(tap_file, 'rb')
-    tapFileInfo = tarHandle.gettarinfo(
-            arcname=os.path.join(directory, os.path.basename(tap_file)),
+    tapFileHandle = open(config['tapfile'], 'rb')
+    tapFileInfo = tarballHandle.gettarinfo(
+            arcname=os.path.join(config['release-name'], tapFileBase),
             fileobj=tapFileHandle,
         )
     tapFileInfo.mode = 0644
-    tarHandle.addfile(tapFileInfo, tapFileHandle)
+    tarballHandle.addfile(tapFileInfo, tapFileHandle)
+
+    tarballHandle.close()
 
-    tarHandle.close()
+    log.msg(format="Created dummy source tarball %(tarballPath)r",
+            tarballPath=tarballPath)
+
+    # Create the spec file in the SPECS directory.
+    specName = "%s.spec" % (config['release-name'],)
+    specPath = os.path.join(buildDir, "SPECS", specName)
+    specHandle = open(specPath, "w")
+    specFileRealData = specFileData % {
+            'description': config['description'],
+            'rpm_file': config['rpmfile'],
+            'version': config['set-version'],
+            'tarfile_basename': tarballName,
+            'tap_file': tapFileBase,
+            'date': time.strftime('%a %b %d %Y', time.localtime(time.time())),
+            'maintainer': config['maintainer'],
+            'long_description': config['long_description'],
+        }
+    specHandle.write(specFileRealData)
+    specHandle.close()
+
+    log.msg(format="Created RPM spec file %(specPath)r",
+            specPath=specPath)
+
+    return specPath
+
+
+
+def run(options=None):
+    #  parse options
+    try:
+        config = MyOptions()
+        config.parseOptions(options)
+    except usage.error, ue:
+         sys.exit("%s: %s" % (sys.argv[0], ue))
 
-    print "Checking content of tarball %r before we hand it to rpmbuild..." % (
-            tarfile_name)
-    os.system('tar tzvf "%(tarfile_name)s"' % vars())
-    print "done."
+    #  create RPM build environment
+    tmp_dir = makeBuildDir()
+    specPath = setupBuildFiles(tmp_dir, config)
 
     #  build rpm
     job = subprocess.Popen([
-            "strace",
-            "-s", "1000",
             "rpmbuild",
             "-vv",
             "--define", "_topdir %s" % (tmp_dir,),
-            "-ta", tarfile_name,
+            "-ba", specPath,
         ], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
     stdout, _ = job.communicate()
 
     # If there was a problem, show people what it was.
-    #if job.returncode != 0:
-    #    print stdout
-    print stdout
+    if job.returncode != 0:
+        print stdout
     
     #  copy the RPMs to the local directory
-    log.msg(os.listdir(tmp_dir))
-    log.msg(os.listdir(os.path.join(tmp_dir, "RPMS")))
-    log.msg(os.listdir(os.path.join(tmp_dir, "SRPMS")))
-    log.msg(os.listdir(os.path.join(tmp_dir, "RPMS", "noarch")))
     rpm_path = glob.glob(os.path.join(tmp_dir, 'RPMS', 'noarch', '*'))[0]
     srpm_path = glob.glob(os.path.join(tmp_dir, 'SRPMS', '*'))[0]
     if not config['quiet']:
diff --git a/twisted/scripts/test/test_tap2rpm.py b/twisted/scripts/test/test_tap2rpm.py
index edabe32..c4b4df2 100644
--- a/twisted/scripts/test/test_tap2rpm.py
+++ b/twisted/scripts/test/test_tap2rpm.py
@@ -153,6 +153,78 @@ class TestTap2RPM(TestCase):
         return d
 
 
+    def test_optionDefaults(self):
+        """
+        Commandline options should default to sensible values.
+
+        "sensible" here is defined as "the same values that previous versions
+        defaulted to".
+        """
+        config = tap2rpm.MyOptions()
+        config.parseOptions([])
+
+        self.assertEquals(config['tapfile'], 'twistd.tap')
+        self.assertEquals(config['maintainer'], 'tap2rpm')
+        self.assertEquals(config['protocol'], 'twistd')
+        self.assertEquals(config['description'], 'A TCP server for twistd')
+        self.assertEquals(config['long_description'],
+                'Automatically created by tap2rpm')
+        self.assertEquals(config['set-version'], '1.0')
+        self.assertEquals(config['rpmfile'], 'twisted-twistd')
+        self.assertEquals(config['type'], 'tap')
+        self.assertEquals(config['quiet'], False)
+        self.assertEquals(config['twistd_option'], 'file')
+        self.assertEquals(config['release-name'], 'twisted-twistd-1.0')
+
+
+    def test_protocolCalculatedFromTapFile(self):
+        """
+        The protocol name defaults to a value based on the tapfile value.
+        """
+        config = tap2rpm.MyOptions()
+        config.parseOptions(['--tapfile', 'pancakes.tap'])
+
+        self.assertEquals(config['tapfile'], 'pancakes.tap')
+        self.assertEquals(config['protocol'], 'pancakes')
+
+
+    def test_optionsDefaultToProtocolValue(self):
+        """
+        Many options default to a value calculated from the protocol name.
+        """
+        config = tap2rpm.MyOptions()
+        config.parseOptions([
+                '--tapfile', 'sausages.tap',
+                '--protocol', 'eggs',
+            ])
+
+        self.assertEquals(config['tapfile'], 'sausages.tap')
+        self.assertEquals(config['maintainer'], 'tap2rpm')
+        self.assertEquals(config['protocol'], 'eggs')
+        self.assertEquals(config['description'], 'A TCP server for eggs')
+        self.assertEquals(config['long_description'],
+                'Automatically created by tap2rpm')
+        self.assertEquals(config['set-version'], '1.0')
+        self.assertEquals(config['rpmfile'], 'twisted-eggs')
+        self.assertEquals(config['type'], 'tap')
+        self.assertEquals(config['quiet'], False)
+        self.assertEquals(config['twistd_option'], 'file')
+        self.assertEquals(config['release-name'], 'twisted-eggs-1.0')
+
+
+    def test_releaseNameDefaultsToRpmfileValue(self):
+        """
+        The release-name option is calculated from rpmfile and set-version.
+        """
+        config = tap2rpm.MyOptions()
+        config.parseOptions([
+                "--rpmfile", "beans",
+                "--set-version", "1.2.3",
+            ])
+
+        self.assertEquals(config['release-name'], 'beans-1.2.3')
+
+
     def test_basicOperation(self):
         """
         Calling tap2rpm should produce an RPM and SRPM with default metadata.