bpo-31904: Add posix module support for VxWorks (GH-12118)

Author: pxinwr

Doc/library/os.rst

@@ -32,6 +32,7 @@ Notes on the availability of these functions:
   objects, and result in an object of the same type, if a path or file name is
   returned.
 
+* On VxWorks, os.fork, os.execv and os.spawn*p* are not supported.
 
 .. note::
 
@@ -3578,6 +3579,9 @@ written in Python, such as a mail server's external command delivery program.
    process.  On Windows, the process id will actually be the process handle, so can
    be used with the :func:`waitpid` function.
 
+   Note on VxWorks, this function doesn't return ``-signal`` when the new process is
+   killed. Instead it raises OSError exception.
+
    The "l" and "v" variants of the :func:`spawn\* <spawnl>` functions differ in how
    command-line arguments are passed.  The "l" variants are perhaps the easiest
    to work with if the number of parameters is fixed when the code is written; the

Lib/test/test_os.py

@@ -1407,6 +1407,8 @@ def test_getrandom_value(self):
 
 @unittest.skipIf(OS_URANDOM_DONT_USE_FD ,
                  "os.random() does not use a file descriptor")
+@unittest.skipIf(sys.platform == "vxworks",
+                 "VxWorks can't set RLIMIT_NOFILE to 1")
 class URandomFDTests(unittest.TestCase):
     @unittest.skipUnless(resource, "test requires the resource module")
     def test_urandom_failure(self):
@@ -1517,7 +1519,8 @@ def mock_execve(name, *args):
         os.execve = orig_execve
         os.defpath = orig_defpath
 
-
+@unittest.skipUnless(hasattr(os, 'execv'),
+                     "need os.execv()")
 class ExecTests(unittest.TestCase):
     @unittest.skipIf(USING_LINUXTHREADS,
                      "avoid triggering a linuxthreads bug: see issue #4970")

Misc/NEWS.d/next/Library/2019-03-01-17-59-39.bpo-31904.38djdk.rst

@@ -0,0 +1 @@
+Add posix module support for VxWorks.

Modules/clinic/posixmodule.c.h

@@ -191,11 +191,13 @@ corresponding Unix manual entries for more information on calls.");
 #define fsync _commit
 #else
 /* Unix functions that the configure script doesn't check for */
+#ifndef __VXWORKS__
 #define HAVE_EXECV      1
 #define HAVE_FORK       1
 #if defined(__USLC__) && defined(__SCO_VERSION__)       /* SCO UDK Compiler */
 #define HAVE_FORK1      1
 #endif
+#endif
 #define HAVE_GETEGID    1
 #define HAVE_GETEUID    1
 #define HAVE_GETGID     1
@@ -227,6 +229,18 @@ extern char        *ctermid_r(char *);
 
 #endif /* !_MSC_VER */
 
+#if defined(__VXWORKS__)
+#include <vxCpuLib.h>
+#include <rtpLib.h>
+#include <wait.h>
+#include <taskLib.h>
+#ifndef _P_WAIT
+#define _P_WAIT          0
+#define _P_NOWAIT        1
+#define _P_NOWAITO       1
+#endif
+#endif /* __VXWORKS__ */
+
 #ifdef HAVE_POSIX_SPAWN
 #include <spawn.h>
 #endif
@@ -1353,7 +1367,7 @@ win32_get_reparse_tag(HANDLE reparse_point_handle, ULONG *reparse_tag)
 */
 #include <crt_externs.h>
 static char **environ;
-#elif !defined(_MSC_VER) && ( !defined(__WATCOMC__) || defined(__QNX__) )
+#elif !defined(_MSC_VER) && (!defined(__WATCOMC__) || defined(__QNX__) || defined(__VXWORKS__))
 extern char **environ;
 #endif /* !_MSC_VER */
 
@@ -4870,7 +4884,7 @@ os__exit_impl(PyObject *module, int status)
 #define EXECV_CHAR char
 #endif
 
-#if defined(HAVE_EXECV) || defined(HAVE_SPAWNV)
+#if defined(HAVE_EXECV) || defined(HAVE_SPAWNV) || defined(HAVE_RTPSPAWN)
 static void
 free_string_array(EXECV_CHAR **array, Py_ssize_t count)
 {
@@ -4908,7 +4922,7 @@ fsconvert_strdup(PyObject *o, EXECV_CHAR **out)
 }
 #endif
 
-#if defined(HAVE_EXECV) || defined (HAVE_FEXECVE)
+#if defined(HAVE_EXECV) || defined (HAVE_FEXECVE) || defined(HAVE_RTPSPAWN)
 static EXECV_CHAR**
 parse_envlist(PyObject* env, Py_ssize_t *envc_ptr)
 {
@@ -5632,8 +5646,41 @@ os_posix_spawnp_impl(PyObject *module, path_t *path, PyObject *argv,
 }
 #endif /* HAVE_POSIX_SPAWNP */
 
-
-#if defined(HAVE_SPAWNV) || defined(HAVE_WSPAWNV)
+#ifdef HAVE_RTPSPAWN
+static intptr_t
+_rtp_spawn(int mode, const char *rtpFileName, const char *argv[],
+               const char  *envp[])
+{
+     RTP_ID rtpid;
+     int status;
+     pid_t res;
+     int async_err = 0;
+
+     /* Set priority=100 and uStackSize=16 MiB (0x1000000) for new processes.
+        uStackSize=0 cannot be used, the default stack size is too small for
+        Python. */
+     if (envp) {
+         rtpid = rtpSpawn(rtpFileName, argv, envp,
+                          100, 0x1000000, 0, VX_FP_TASK);
+     }
+     else {
+         rtpid = rtpSpawn(rtpFileName, argv, (const char **)environ,
+                          100, 0x1000000, 0, VX_FP_TASK);
+     }
+     if ((rtpid != RTP_ID_ERROR) && (mode == _P_WAIT)) {
+         do {
+             res = waitpid((pid_t)rtpid, &status, 0);
+         } while (res < 0 && errno == EINTR && !(async_err = PyErr_CheckSignals()));
+
+         if (res < 0)
+             return RTP_ID_ERROR;
+         return ((intptr_t)status);
+     }
+     return ((intptr_t)rtpid);
+}
+#endif
+
+#if defined(HAVE_SPAWNV) || defined(HAVE_WSPAWNV) || defined(HAVE_RTPSPAWN)
 /*[clinic input]
 os.spawnv
 
@@ -5703,13 +5750,17 @@ os_spawnv_impl(PyObject *module, int mode, path_t *path, PyObject *argv)
     }
     argvlist[argc] = NULL;
 
+#if !defined(HAVE_RTPSPAWN)
     if (mode == _OLD_P_OVERLAY)
         mode = _P_OVERLAY;
+#endif
 
     Py_BEGIN_ALLOW_THREADS
     _Py_BEGIN_SUPPRESS_IPH
 #ifdef HAVE_WSPAWNV
     spawnval = _wspawnv(mode, path->wide, argvlist);
+#elif defined(HAVE_RTPSPAWN)
+    spawnval = _rtp_spawn(mode, path->narrow, (const char **)argvlist, NULL);
 #else
     spawnval = _spawnv(mode, path->narrow, argvlist);
 #endif
@@ -5808,13 +5859,18 @@ os_spawnve_impl(PyObject *module, int mode, path_t *path, PyObject *argv,
     if (envlist == NULL)
         goto fail_1;
 
+#if !defined(HAVE_RTPSPAWN)
     if (mode == _OLD_P_OVERLAY)
         mode = _P_OVERLAY;
+#endif
 
     Py_BEGIN_ALLOW_THREADS
     _Py_BEGIN_SUPPRESS_IPH
 #ifdef HAVE_WSPAWNV
     spawnval = _wspawnve(mode, path->wide, argvlist, envlist);
+#elif defined(HAVE_RTPSPAWN)
+    spawnval = _rtp_spawn(mode, path->narrow, (const char **)argvlist,
+                           (const char **)envlist);
 #else
     spawnval = _spawnve(mode, path->narrow, argvlist, envlist);
 #endif
@@ -13844,11 +13900,13 @@ all_ins(PyObject *m)
     if (PyModule_AddIntConstant(m, "POSIX_SPAWN_DUP2", POSIX_SPAWN_DUP2)) return -1;
 #endif
 
-#ifdef HAVE_SPAWNV
+#if defined(HAVE_SPAWNV) || defined (HAVE_RTPSPAWN)
     if (PyModule_AddIntConstant(m, "P_WAIT", _P_WAIT)) return -1;
     if (PyModule_AddIntConstant(m, "P_NOWAIT", _P_NOWAIT)) return -1;
-    if (PyModule_AddIntConstant(m, "P_OVERLAY", _OLD_P_OVERLAY)) return -1;
     if (PyModule_AddIntConstant(m, "P_NOWAITO", _P_NOWAITO)) return -1;
+#endif
+#ifdef HAVE_SPAWNV
+    if (PyModule_AddIntConstant(m, "P_OVERLAY", _OLD_P_OVERLAY)) return -1;
     if (PyModule_AddIntConstant(m, "P_DETACH", _P_DETACH)) return -1;
 #endif
 

Modules/posixmodule.c

@@ -11484,7 +11484,7 @@ for ac_func in alarm accept4 setitimer getitimer bind_textdomain_codeset chown \
  sigtimedwait sigwait sigwaitinfo snprintf strftime strlcpy strsignal symlinkat sync \
  sysconf tcgetpgrp tcsetpgrp tempnam timegm times tmpfile tmpnam tmpnam_r \
  truncate uname unlinkat unsetenv utimensat utimes waitid waitpid wait3 wait4 \
- wcscoll wcsftime wcsxfrm wmemcmp writev _getpty
+ wcscoll wcsftime wcsxfrm wmemcmp writev _getpty rtpSpawn
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"

configure

@@ -3541,7 +3541,7 @@ AC_CHECK_FUNCS(alarm accept4 setitimer getitimer bind_textdomain_codeset chown \
  sigtimedwait sigwait sigwaitinfo snprintf strftime strlcpy strsignal symlinkat sync \
  sysconf tcgetpgrp tcsetpgrp tempnam timegm times tmpfile tmpnam tmpnam_r \
  truncate uname unlinkat unsetenv utimensat utimes waitid waitpid wait3 wait4 \
- wcscoll wcsftime wcsxfrm wmemcmp writev _getpty)
+ wcscoll wcsftime wcsxfrm wmemcmp writev _getpty rtpSpawn)
 
 # Force lchmod off for Linux. Linux disallows changing the mode of symbolic
 # links. Some libc implementations have a stub lchmod implementation that always

configure.ac

@@ -835,6 +835,9 @@
 /* Define to 1 if you have the `round' function. */
 #undef HAVE_ROUND
 
+/* Define to 1 if you have the `rtpSpawn' function. */
+#undef HAVE_RTPSPAWN
+
 /* Define to 1 if you have the `sched_get_priority_max' function. */
 #undef HAVE_SCHED_GET_PRIORITY_MAX