asyncio, Tulip issue 130: Add more checks on subprocess_exec/subprocess_shell
parameters
diff --git a/Lib/asyncio/base_events.py b/Lib/asyncio/base_events.py
index 4b7b161..5765f47 100644
--- a/Lib/asyncio/base_events.py
+++ b/Lib/asyncio/base_events.py
@@ -558,7 +558,7 @@
                          stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                          universal_newlines=False, shell=True, bufsize=0,
                          **kwargs):
-        if not isinstance(cmd, str):
+        if not isinstance(cmd, (bytes, str)):
             raise ValueError("cmd must be a string")
         if universal_newlines:
             raise ValueError("universal_newlines must be False")
@@ -572,7 +572,7 @@
         return transport, protocol
 
     @tasks.coroutine
-    def subprocess_exec(self, protocol_factory, *args, stdin=subprocess.PIPE,
+    def subprocess_exec(self, protocol_factory, program, *args, stdin=subprocess.PIPE,
                         stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                         universal_newlines=False, shell=False, bufsize=0,
                         **kwargs):
@@ -582,9 +582,15 @@
             raise ValueError("shell must be False")
         if bufsize != 0:
             raise ValueError("bufsize must be 0")
+        popen_args = (program,) + args
+        for arg in popen_args:
+            if not isinstance(arg, (str, bytes)):
+                raise TypeError("program arguments must be "
+                                "a bytes or text string, not %s"
+                                % type(arg).__name__)
         protocol = protocol_factory()
         transport = yield from self._make_subprocess_transport(
-            protocol, args, False, stdin, stdout, stderr, bufsize, **kwargs)
+            protocol, popen_args, False, stdin, stdout, stderr, bufsize, **kwargs)
         return transport, protocol
 
     def _add_callback(self, handle):
diff --git a/Lib/asyncio/subprocess.py b/Lib/asyncio/subprocess.py
index 848d64f..8d1a407 100644
--- a/Lib/asyncio/subprocess.py
+++ b/Lib/asyncio/subprocess.py
@@ -180,7 +180,7 @@
     return Process(transport, protocol, loop)
 
 @tasks.coroutine
-def create_subprocess_exec(*args, stdin=None, stdout=None, stderr=None,
+def create_subprocess_exec(program, *args, stdin=None, stdout=None, stderr=None,
                            loop=None, limit=streams._DEFAULT_LIMIT, **kwds):
     if loop is None:
         loop = events.get_event_loop()
@@ -188,7 +188,8 @@
                                                         loop=loop)
     transport, protocol = yield from loop.subprocess_exec(
                                             protocol_factory,
-                                            *args, stdin=stdin, stdout=stdout,
+                                            program, *args,
+                                            stdin=stdin, stdout=stdout,
                                             stderr=stderr, **kwds)
     yield from protocol.waiter
     return Process(transport, protocol, loop)