bpo-20104: Add flag capabilities to posix_spawn

Doc/library/os.rst

@@ -3392,7 +3392,9 @@ written in Python, such as a mail server's external command delivery program.
    subprocesses.
 
 
-.. function:: posix_spawn(path, argv, env, file_actions=None)
+.. function:: posix_spawn(path, argv, env, file_actions=None, /, *, \
+                          setpgroup=None, resetids=False, setsigmask=(), \
+                          setsigdef=(), scheduler=None)
 
    Wraps the :c:func:`posix_spawn` C library API for use from Python.
 
@@ -3430,6 +3432,36 @@ written in Python, such as a mail server's external command delivery program.
    :c:func:`posix_spawn_file_actions_adddup2` API calls used to prepare
    for the :c:func:`posix_spawn` call itself.
 
+   The *setpgroup* argument will set the process group of the child to the value
+   specified. If the value specified is 0, the child's process group ID will be
+   made the same as its process ID. If the value of *setpgroup* is not set, the
+   child will inherit the parent's process group ID. This argument corresponds
+   to the C library :c:data:`POSIX_SPAWN_SETPGROUP` flag.
+
+   If the *resetids* argument is ``True`` it will reset the effective UID and
+   GID of the child to the real UID and GID of the parent process. If the
+   argument is ``False``, then the child retains the effective UID and GID of
+   the parent. In either case, if the set-user-ID and set-group-ID permission
+   bits are enabled on the executable file, their effect will override the
+   setting of the effective UID and GID. This argument corresponds to the C
+   library :c:data:`POSIX_SPAWN_RESETIDS` flag.
+
+   The *setsigmask* argument will set the signal mask to the signal set
+   specified. If the parameter is not used, then the child inherits the
+   parent's signal mask. This argument corresponds to the C library
+   :c:data:`POSIX_SPAWN_SETSIGMASK` flag.
+
+   The *sigdef* argument will reset the disposition of all signals in the set
+   specified. This argument corresponds to the C library
+   :c:data:`POSIX_SPAWN_SETSIGDEF` flag.
+
+   The *scheduler* argument must be a tuple containing the (optional) scheduler
+   policy and an instance of :class:`sched_param` with the scheduler parameters.
+   A value of ``None`` in the place of the scheduler policy indicates that is
+   not being provided. This argument is a combination of the C library
+   :c:data:`POSIX_SPAWN_SETSCHEDPARAM` and :c:data:`POSIX_SPAWN_SETSCHEDULER`
+   flags.
+
    .. versionadded:: 3.7
 
 

Lib/test/test_posix.py

@@ -8,6 +8,7 @@
 
 import errno
 import sys
+import signal
 import time
 import os
 import platform
@@ -16,6 +17,7 @@
 import tempfile
 import unittest
 import warnings
+import textwrap
 
 _DUMMY_SYMLINK = os.path.join(tempfile.gettempdir(),
                               support.TESTFN + '-dummy-symlink')
@@ -1476,6 +1478,147 @@ def test_empty_file_actions(self):
         )
         self.assertEqual(os.waitpid(pid, 0), (pid, 0))
 
+    def test_resetids_explicit_default(self):
+        pid = posix.posix_spawn(
+            sys.executable,
+            [sys.executable, '-c', 'pass'],
+            os.environ,
+            resetids=False
+        )
+        self.assertEqual(os.waitpid(pid, 0), (pid, 0))
+
+    def test_resetids(self):
+        pid = posix.posix_spawn(
+            sys.executable,
+            [sys.executable, '-c', 'pass'],
+            os.environ,
+            resetids=True
+        )
+        self.assertEqual(os.waitpid(pid, 0), (pid, 0))
+
+    def test_resetids_wrong_type(self):
+        with self.assertRaises(TypeError):
+            posix.posix_spawn(sys.executable,
+                              [sys.executable, "-c", "pass"],
+                              os.environ, resetids=None)
+
+    def test_setpgroup(self):
+        pid = posix.posix_spawn(
+            sys.executable,
+            [sys.executable, '-c', 'pass'],
+            os.environ,
+            setpgroup=os.getpgrp()
+        )
+        self.assertEqual(os.waitpid(pid, 0), (pid, 0))
+
+    def test_setpgroup_wrong_type(self):
+        with self.assertRaises(TypeError):
+            posix.posix_spawn(sys.executable,
+                              [sys.executable, "-c", "pass"],
+                              os.environ, setpgroup="023")
+
+    @unittest.skipUnless(hasattr(signal, 'pthread_sigmask'),
+                           'need signal.pthread_sigmask()')
+    def test_setsigmask(self):
+        code = textwrap.dedent("""\
+            import _testcapi, signal
+            _testcapi.raise_signal(signal.SIGUSR1)""")
+
+        pid = posix.posix_spawn(
+            sys.executable,
+            [sys.executable, '-c', code],
+            os.environ,
+            setsigmask=[signal.SIGUSR1]
+        )
+        self.assertEqual(os.waitpid(pid, 0), (pid, 0))
+
+    def test_setsigmask_wrong_type(self):
+        with self.assertRaises(TypeError):
+            posix.posix_spawn(sys.executable,
+                              [sys.executable, "-c", "pass"],
+                              os.environ, setsigmask=34)
+        with self.assertRaises(TypeError):
+            posix.posix_spawn(sys.executable,
+                              [sys.executable, "-c", "pass"],
+                              os.environ, setsigmask=["j"])
+        with self.assertRaises(ValueError):
+            posix.posix_spawn(sys.executable,
+                              [sys.executable, "-c", "pass"],
+                              os.environ, setsigmask=[signal.NSIG,
+                                                      signal.NSIG+1])
+
+    @unittest.skipUnless(hasattr(signal, 'pthread_sigmask'),
+                         'need signal.pthread_sigmask()')
+    def test_setsigdef(self):
+        original_handler = signal.signal(signal.SIGUSR1, signal.SIG_IGN)
+        code = textwrap.dedent("""\
+            import _testcapi, signal
+            _testcapi.raise_signal(signal.SIGUSR1)""")
+        try:
+            pid = posix.posix_spawn(
+                sys.executable,
+                [sys.executable, '-c', code],
+                os.environ,
+                setsigdef=[signal.SIGUSR1]
+            )
+        finally:
+            signal.signal(signal.SIGUSR1, original_handler)
+
+        pid2, status = os.waitpid(pid, 0)
+        self.assertEqual(pid2, pid)
+        self.assertTrue(os.WIFSIGNALED(status), status)
+        self.assertEqual(os.WTERMSIG(status), signal.SIGUSR1)
+
+    def test_setsigdef_wrong_type(self):
+        with self.assertRaises(TypeError):
+            posix.posix_spawn(sys.executable,
+                              [sys.executable, "-c", "pass"],
+                              os.environ, setsigdef=34)
+        with self.assertRaises(TypeError):
+            posix.posix_spawn(sys.executable,
+                              [sys.executable, "-c", "pass"],
+                              os.environ, setsigdef=["j"])
+        with self.assertRaises(ValueError):
+            posix.posix_spawn(sys.executable,
+                              [sys.executable, "-c", "pass"],
+                              os.environ, setsigdef=[signal.NSIG, signal.NSIG+1])
+
+    @unittest.skipUnless(hasattr(posix, 'sched_setscheduler'), "can't change scheduler")
+    def test_setscheduler_only_param(self):
+        policy = os.sched_getscheduler(0)
+        priority = os.sched_get_priority_min(policy)
+        code = textwrap.dedent(f"""\
+            import os
+            if os.sched_getscheduler(0) != {policy}:
+                os.exit(101)
+            if os.sched_getparam(0).sched_priority != {priority}:
+                os.exit(102)""")
+        pid = posix.posix_spawn(
+            sys.executable,
+            [sys.executable, '-c', code],
+            os.environ,
+            scheduler=(None, os.sched_param(priority))
+        )
+        self.assertEqual(os.waitpid(pid, 0), (pid, 0))
+
+    @unittest.skipUnless(hasattr(posix, 'sched_setscheduler'), "can't change scheduler")
+    def test_setscheduler_with_policy(self):
+        policy = os.sched_getscheduler(0)
+        priority = os.sched_get_priority_min(policy)
+        code = textwrap.dedent(f"""\
+            import os
+            if os.sched_getscheduler(0) != {policy}:
+                os.exit(101)
+            if os.sched_getparam(0).sched_priority != {priority}:
+                os.exit(102)""")
+        pid = posix.posix_spawn(
+            sys.executable,
+            [sys.executable, '-c', code],
+            os.environ,
+            scheduler=(policy, os.sched_param(priority))
+        )
+        self.assertEqual(os.waitpid(pid, 0), (pid, 0))
+
     def test_multiple_file_actions(self):
         file_actions = [
             (os.POSIX_SPAWN_OPEN, 3, os.path.realpath(__file__), os.O_RDONLY, 0),

Misc/NEWS.d/next/Core and Builtins/2018-05-05-23-26-58.bpo-20104.tDBciE.rst

@@ -0,0 +1,2 @@
+Added support for the `setpgroup`, `resetids`, `setsigmask`, `setsigdef` and
+`scheduler` parameters of `posix_spawn`. Patch by Pablo Galindo.