Merge pull request #49 from opalmer/get_current_process

Implement GetProcessId() and GetCurrentProcess()

pywincffi/core/cdefs/headers/functions.h

@@ -10,6 +10,8 @@ VOID SetLastError(DWORD);
 
 // Processes
 HANDLE OpenProcess(DWORD, BOOL, DWORD);
+HANDLE GetCurrentProcess();
+DWORD GetProcessId(HANDLE);
 
 // Pipes
 BOOL CreatePipe(PHANDLE, PHANDLE, LPSECURITY_ATTRIBUTES, DWORD);

pywincffi/kernel32/process.py

@@ -18,7 +18,7 @@
 import six
 
 from pywincffi.core import dist
-from pywincffi.core.checks import input_check, error_check
+from pywincffi.core.checks import Enums, input_check, error_check
 
 
 def OpenProcess(dwDesiredAccess, bInheritHandle, dwProcessId):
@@ -55,3 +55,45 @@ def OpenProcess(dwDesiredAccess, bInheritHandle, dwProcessId):
     )
     error_check("OpenProcess")
     return handle
+
+
+def GetCurrentProcess():
+    """
+    Returns a handle to the current thread.
+
+    .. seealso::
+
+        https://msdn.microsoft.com/en-us/library/ms683179
+
+    .. note::
+
+        Calling :func:`pywincffi.kernel32.io.CloseHandle` on the handle
+        produced by this function will produce an exception.
+
+    :returns:
+        The handle to the current process.
+    """
+    _, library = dist.load()
+    return library.GetCurrentProcess()
+
+
+def GetProcessId(Process):  # pylint: disable=invalid-name
+    """
+    Returns the pid of the process handle provided in ``Process``.
+
+    .. seealso::
+
+        https://msdn.microsoft.com/en-us/library/ms683215
+
+    :param handle Process:
+        The handle of the process to re
+
+    :return:
+        Returns an integer which represents the pid of the given
+        process handle.
+    """
+    input_check("Process", Process, Enums.HANDLE)
+    _, library = dist.load()
+    pid = library.GetProcessId(Process)
+    error_check("GetProcessId")
+    return pid

tests/test_kernel32/test_process.py

@@ -1,15 +1,18 @@
 import os
+import subprocess
+import sys
 
 from pywincffi.core import dist
 from pywincffi.dev.testutil import TestCase
 from pywincffi.exceptions import WindowsAPIError
 from pywincffi.kernel32.io import CloseHandle
-from pywincffi.kernel32.process import OpenProcess
+from pywincffi.kernel32.process import (
+    OpenProcess, GetCurrentProcess, GetProcessId)
 
 
 class TestOpenProcess(TestCase):
     """
-    Tests for :func:`pywincffi.kernel32.OpenProcess`
+    Tests for :func:`pywincffi.kernel32.process.OpenProcess`
     """
     def test_returns_handle(self):
         ffi, library = dist.load()
@@ -31,10 +34,64 @@ def test_access_denied_for_null_desired_access(self):
 
         self.assertEqual(error.exception.code, 5)
 
+    def test_get_process_id_current_process(self):
+        # We should be able to access the pid of the process
+        # we created a handle to.
+        _, library = dist.load()
+
+        handle = OpenProcess(
+            library.PROCESS_QUERY_INFORMATION,
+            False,
+            os.getpid()
+        )
+        self.assertEqual(GetProcessId(handle), os.getpid())
+        CloseHandle(handle)
+
+
+class TestGetCurrentProcess(TestCase):
+    """
+    Tests for :func:`pywincffi.kernel32.process.GetCurrentProcess`
+    """
+    def test_returns_handle(self):
+        ffi, _ = dist.load()
+        handle = GetCurrentProcess()
+        typeof = ffi.typeof(handle)
+        self.assertEqual(typeof.kind, "pointer")
+        self.assertEqual(typeof.cname, "void *")
+
+    def test_returns_same_handle(self):
+        # GetCurrentProcess is somewhat special in that it will
+        # always return a handle to the same object.  However, __eq__ is not
+        # opaque so the string representation of the two handles
+        # should always match since it contains the address of the object
+        # in memory.
+        self.assertEqual(repr(GetCurrentProcess()), repr(GetCurrentProcess()))
+
+    def test_handle_is_current_process(self):
+        handle = GetCurrentProcess()
+        self.assertEqual(GetProcessId(handle), os.getpid())
+
     def test_handle_is_valid(self):
         _, library = dist.load()
         handle = OpenProcess(
             library.PROCESS_QUERY_INFORMATION, False, os.getpid())
 
         # If the handle were invalid, this would fail.
         CloseHandle(handle)
+
+
+class TestGetProcessId(TestCase):
+    """
+    Tests for :func:`pywincffi.kernel32.process.GetProcessId`
+    """
+    def test_get_pid_of_external_process(self):
+        _, library = dist.load()
+        python = subprocess.Popen(
+            [sys.executable, "-c", "import time; time.sleep(3)"]
+        )
+        self.addCleanup(python.terminate)
+        expected_pid = python.pid
+        handle = OpenProcess(
+            library.PROCESS_QUERY_INFORMATION, False, expected_pid)
+        self.assertEqual(GetProcessId(handle), expected_pid)
+        CloseHandle(handle)