diff --git a/distutils/core.py b/distutils/core.py
index d603d4a4..f43888ea 100644
--- a/distutils/core.py
+++ b/distutils/core.py
@@ -8,6 +8,7 @@
 
 import os
 import sys
+import tokenize
 
 from distutils.debug import DEBUG
 from distutils.errors import *
@@ -144,29 +145,41 @@ class found in 'cmdclass' is used in place of the default, which is
 
     # And finally, run all the commands found on the command line.
     if ok:
-        try:
-            dist.run_commands()
-        except KeyboardInterrupt:
-            raise SystemExit("interrupted")
-        except OSError as exc:
-            if DEBUG:
-                sys.stderr.write("error: %s\n" % (exc,))
-                raise
-            else:
-                raise SystemExit("error: %s" % (exc,))
-
-        except (DistutilsError,
-                CCompilerError) as msg:
-            if DEBUG:
-                raise
-            else:
-                raise SystemExit("error: " + str(msg))
+        return run_commands(dist)
 
     return dist
 
 # setup ()
 
 
+def run_commands (dist):
+    """Given a Distribution object run all the commands,
+    raising ``SystemExit`` errors in the case of failure.
+
+    This function assumes that either ``sys.argv`` or ``dist.script_args``
+    is already set accordingly.
+    """
+    try:
+        dist.run_commands()
+    except KeyboardInterrupt:
+        raise SystemExit("interrupted")
+    except OSError as exc:
+        if DEBUG:
+            sys.stderr.write("error: %s\n" % (exc,))
+            raise
+        else:
+            raise SystemExit("error: %s" % (exc,))
+
+    except (DistutilsError,
+            CCompilerError) as msg:
+        if DEBUG:
+            raise
+        else:
+            raise SystemExit("error: " + str(msg))
+
+    return dist
+
+
 def run_setup (script_name, script_args=None, stop_after="run"):
     """Run a setup script in a somewhat controlled environment, and
     return the Distribution instance that drives things.  This is useful
@@ -205,14 +218,16 @@ def run_setup (script_name, script_args=None, stop_after="run"):
     _setup_stop_after = stop_after
 
     save_argv = sys.argv.copy()
-    g = {'__file__': script_name}
+    g = {'__file__': script_name, '__name__': '__main__'}
     try:
         try:
             sys.argv[0] = script_name
             if script_args is not None:
                 sys.argv[1:] = script_args
-            with open(script_name, 'rb') as f:
-                exec(f.read(), g)
+            # tokenize.open supports automatic encoding detection
+            with tokenize.open(script_name) as f:
+                code = f.read().replace(r'\r\n', r'\n')
+                exec(code, g)
         finally:
             sys.argv = save_argv
             _setup_stop_after = None
diff --git a/distutils/tests/test_core.py b/distutils/tests/test_core.py
index 666ff4a3..d99cfd26 100644
--- a/distutils/tests/test_core.py
+++ b/distutils/tests/test_core.py
@@ -10,6 +10,7 @@
 import unittest
 from distutils.tests import support
 from distutils import log
+from distutils.dist import Distribution
 
 # setup script that uses __file__
 setup_using___file__ = """\
@@ -45,6 +46,16 @@ class install(_install):
 setup(cmdclass={'install': install})
 """
 
+setup_within_if_main = """\
+from distutils.core import setup
+
+def main():
+    return setup(name="setup_within_if_main")
+
+if __name__ == "__main__":
+    main()
+"""
+
 class CoreTestCase(support.EnvironGuard, unittest.TestCase):
 
     def setUp(self):
@@ -115,6 +126,20 @@ def test_run_setup_uses_current_dir(self):
             output = output[:-1]
         self.assertEqual(cwd, output)
 
+    def test_run_setup_within_if_main(self):
+        dist = distutils.core.run_setup(
+            self.write_setup(setup_within_if_main), stop_after="config")
+        self.assertIsInstance(dist, Distribution)
+        self.assertEqual(dist.get_name(), "setup_within_if_main")
+
+    def test_run_commands(self):
+        sys.argv = ['setup.py', 'build']
+        dist = distutils.core.run_setup(
+            self.write_setup(setup_within_if_main), stop_after="commandline")
+        self.assertNotIn('build', dist.have_run)
+        distutils.core.run_commands(dist)
+        self.assertIn('build', dist.have_run)
+
     def test_debug_mode(self):
         # this covers the code called when DEBUG is set
         sys.argv = ['setup.py', '--name']