bpo-39406: Implement os.putenv() with setenv() if available

Misc/NEWS.d/next/Library/2020-01-21-09-48-44.bpo-39406.MQNReV.rst

@@ -0,0 +1,4 @@
+If ``setenv()`` C function is available, :func:`os.putenv` is now implemented
+with ``setenv()`` instead of ``putenv()``, so Python doesn't have to handle the
+environment variable memory. On Windows, :func:`os.putenv` is now implemented
+with ``SetEnvironmentVariableW()``.

Modules/posixmodule.c

@@ -819,9 +819,18 @@ dir_fd_converter(PyObject *o, void *p)
     }
 }
 
+#if !defined(MS_WINDOWS) && (defined(HAVE_PUTENV) && !defined(HAVE_SETENV))
+#  define PY_PUTENV_DICT
+#endif
+
 typedef struct {
     PyObject *billion;
-    PyObject *posix_putenv_garbage;
+#ifdef PY_PUTENV_DICT
+    /* putenv() requires to manage the memory manually: use a Python dict
+       object mapping name (bytes) to env (bytes) where env is a bytes string
+       like "name=value\0". */
+    PyObject *posix_putenv_dict;
+#endif
     PyObject *DirEntryType;
     PyObject *ScandirIteratorType;
 #if defined(HAVE_SCHED_SETPARAM) || defined(HAVE_SCHED_SETSCHEDULER) || defined(POSIX_SPAWN_SETSCHEDULER) || defined(POSIX_SPAWN_SETSCHEDPARAM)
@@ -2105,7 +2114,9 @@ static int
 _posix_clear(PyObject *module)
 {
     Py_CLEAR(_posixstate(module)->billion);
-    Py_CLEAR(_posixstate(module)->posix_putenv_garbage);
+#ifdef PY_PUTENV_DICT
+    Py_CLEAR(_posixstate(module)->posix_putenv_dict);
+#endif
     Py_CLEAR(_posixstate(module)->DirEntryType);
     Py_CLEAR(_posixstate(module)->ScandirIteratorType);
 #if defined(HAVE_SCHED_SETPARAM) || defined(HAVE_SCHED_SETSCHEDULER) || defined(POSIX_SPAWN_SETSCHEDULER) || defined(POSIX_SPAWN_SETSCHEDPARAM)
@@ -2130,7 +2141,9 @@ static int
 _posix_traverse(PyObject *module, visitproc visit, void *arg)
 {
     Py_VISIT(_posixstate(module)->billion);
-    Py_VISIT(_posixstate(module)->posix_putenv_garbage);
+#ifdef PY_PUTENV_DICT
+    Py_VISIT(_posixstate(module)->posix_putenv_dict);
+#endif
     Py_VISIT(_posixstate(module)->DirEntryType);
     Py_VISIT(_posixstate(module)->ScandirIteratorType);
 #if defined(HAVE_SCHED_SETPARAM) || defined(HAVE_SCHED_SETSCHEDULER) || defined(POSIX_SPAWN_SETSCHEDULER) || defined(POSIX_SPAWN_SETSCHEDPARAM)
@@ -10047,21 +10060,22 @@ os_posix_fadvise_impl(PyObject *module, int fd, Py_off_t offset,
 }
 #endif /* HAVE_POSIX_FADVISE && !POSIX_FADVISE_AIX_BUG */
 
-#ifdef HAVE_PUTENV
 
+#ifdef PY_PUTENV_DICT
 static void
-posix_putenv_garbage_setitem(PyObject *name, PyObject *value)
+posix_putenv_dict_setitem(PyObject *name, PyObject *value)
 {
-    /* Install the first arg and newstr in posix_putenv_garbage;
+    /* Install the first arg and newstr in posix_putenv_dict;
      * this will cause previous value to be collected.  This has to
      * happen after the real putenv() call because the old value
      * was still accessible until then. */
-    if (PyDict_SetItem(_posixstate_global->posix_putenv_garbage, name, value))
+    if (PyDict_SetItem(_posixstate_global->posix_putenv_dict, name, value))
         /* really not much we can do; just leak */
         PyErr_Clear();
     else
         Py_DECREF(value);
 }
+#endif  /* PY_PUTENV_DICT */
 
 
 #ifdef MS_WINDOWS
@@ -10079,9 +10093,6 @@ static PyObject *
 os_putenv_impl(PyObject *module, PyObject *name, PyObject *value)
 /*[clinic end generated code: output=d29a567d6b2327d2 input=ba586581c2e6105f]*/
 {
-    const wchar_t *env;
-    Py_ssize_t size;
-
     /* Search from index 1 because on Windows starting '=' is allowed for
        defining hidden environment variables. */
     if (PyUnicode_GET_LENGTH(name) == 0 ||
@@ -10090,38 +10101,29 @@ os_putenv_impl(PyObject *module, PyObject *name, PyObject *value)
         PyErr_SetString(PyExc_ValueError, "illegal environment variable name");
         return NULL;
     }
-    PyObject *unicode = PyUnicode_FromFormat("%U=%U", name, value);
-    if (unicode == NULL) {
-        return NULL;
-    }
 
-    env = PyUnicode_AsUnicodeAndSize(unicode, &size);
-    if (env == NULL)
-        goto error;
-    if (size > _MAX_ENV) {
-        PyErr_Format(PyExc_ValueError,
-                     "the environment variable is longer than %u characters",
-                     _MAX_ENV);
-        goto error;
+    /* PyUnicode_AsWideCharString() rejects embedded null characters */
+    wchar_t *name_str = PyUnicode_AsWideCharString(name, NULL);
+    if (name_str == NULL) {
+        return NULL;
     }
-    if (wcslen(env) != (size_t)size) {
-        PyErr_SetString(PyExc_ValueError, "embedded null character");
-        goto error;
+    wchar_t *value_str = PyUnicode_AsWideCharString(value, NULL);
+    if (value_str == NULL) {
+        PyMem_Free(name_str);
+        return NULL;
     }
 
-    if (_wputenv(env)) {
-        posix_error();
-        goto error;
+    BOOL ok = SetEnvironmentVariableW(name_str, value_str);
+    PyMem_Free(name_str);
+    PyMem_Free(value_str);
+
+    if (!ok) {
+        return PyErr_SetFromWindowsErr(0);
     }
 
-    posix_putenv_garbage_setitem(name, unicode);
     Py_RETURN_NONE;
-
-error:
-    Py_DECREF(unicode);
-    return NULL;
 }
-#else /* MS_WINDOWS */
+#elif defined(HAVE_PUTENV)
 /*[clinic input]
 os.putenv
 
@@ -10136,31 +10138,38 @@ static PyObject *
 os_putenv_impl(PyObject *module, PyObject *name, PyObject *value)
 /*[clinic end generated code: output=d29a567d6b2327d2 input=a97bc6152f688d31]*/
 {
-    PyObject *bytes = NULL;
-    char *env;
     const char *name_string = PyBytes_AS_STRING(name);
     const char *value_string = PyBytes_AS_STRING(value);
 
     if (strchr(name_string, '=') != NULL) {
         PyErr_SetString(PyExc_ValueError, "illegal environment variable name");
         return NULL;
     }
-    bytes = PyBytes_FromFormat("%s=%s", name_string, value_string);
+
+#ifdef HAVE_SETENV
+    if (setenv(name_string, value_string, 1)) {
+        return posix_error();
+    }
+#else
+    PyObject *bytes = PyBytes_FromFormat("%s=%s", name_string, value_string);
     if (bytes == NULL) {
         return NULL;
     }
 
-    env = PyBytes_AS_STRING(bytes);
+    char *env = PyBytes_AS_STRING(bytes);
     if (putenv(env)) {
         Py_DECREF(bytes);
         return posix_error();
     }
 
-    posix_putenv_garbage_setitem(name, bytes);
+#ifdef PY_PUTENV_DICT
+    posix_putenv_dict_setitem(name, bytes);
+#endif
+#endif  /* !HAVE_SETENV */
+
     Py_RETURN_NONE;
 }
-#endif /* MS_WINDOWS */
-#endif /* HAVE_PUTENV */
+#endif /* HAVE_PUTENV  */
 
 
 #ifdef HAVE_UNSETENV
@@ -10188,18 +10197,21 @@ os_unsetenv_impl(PyObject *module, PyObject *name)
         return posix_error();
 #endif
 
-    /* Remove the key from posix_putenv_garbage;
+#ifdef PY_PUTENV_DICT
+    /* Remove the key from posix_putenv_dict;
      * this will cause it to be collected.  This has to
      * happen after the real unsetenv() call because the
      * old value was still accessible until then.
      */
-    if (PyDict_DelItem(_posixstate(module)->posix_putenv_garbage, name)) {
+    if (PyDict_DelItem(_posixstate(module)->posix_putenv_dict, name)) {
         /* really not much we can do; just leak */
         if (!PyErr_ExceptionMatches(PyExc_KeyError)) {
             return NULL;
         }
         PyErr_Clear();
     }
+#endif  /* PY_PUTENV_DICT */
+
     Py_RETURN_NONE;
 }
 #endif /* HAVE_UNSETENV */
@@ -14496,10 +14508,10 @@ INITFUNC(void)
     Py_INCREF(PyExc_OSError);
     PyModule_AddObject(m, "error", PyExc_OSError);
 
-#ifdef HAVE_PUTENV
+#ifdef PY_PUTENV_DICT
     /* Save putenv() parameters as values here, so we can collect them when they
      * get re-set with another call for the same key. */
-    _posixstate(m)->posix_putenv_garbage = PyDict_New();
+    _posixstate(m)->posix_putenv_dict = PyDict_New();
 #endif
 
 #if defined(HAVE_WAITID) && !defined(__APPLE__)

configure

@@ -782,7 +782,6 @@ infodir
 docdir
 oldincludedir
 includedir
-runstatedir
 localstatedir
 sharedstatedir
 sysconfdir
@@ -896,7 +895,6 @@ datadir='${datarootdir}'
 sysconfdir='${prefix}/etc'
 sharedstatedir='${prefix}/com'
 localstatedir='${prefix}/var'
-runstatedir='${localstatedir}/run'
 includedir='${prefix}/include'
 oldincludedir='/usr/include'
 docdir='${datarootdir}/doc/${PACKAGE_TARNAME}'
@@ -1149,15 +1147,6 @@ do
   | -silent | --silent | --silen | --sile | --sil)
     silent=yes ;;
 
-  -runstatedir | --runstatedir | --runstatedi | --runstated \
-  | --runstate | --runstat | --runsta | --runst | --runs \
-  | --run | --ru | --r)
-    ac_prev=runstatedir ;;
-  -runstatedir=* | --runstatedir=* | --runstatedi=* | --runstated=* \
-  | --runstate=* | --runstat=* | --runsta=* | --runst=* | --runs=* \
-  | --run=* | --ru=* | --r=*)
-    runstatedir=$ac_optarg ;;
-
   -sbindir | --sbindir | --sbindi | --sbind | --sbin | --sbi | --sb)
     ac_prev=sbindir ;;
   -sbindir=* | --sbindir=* | --sbindi=* | --sbind=* | --sbin=* \
@@ -1295,7 +1284,7 @@ fi
 for ac_var in	exec_prefix prefix bindir sbindir libexecdir datarootdir \
 		datadir sysconfdir sharedstatedir localstatedir includedir \
 		oldincludedir docdir infodir htmldir dvidir pdfdir psdir \
-		libdir localedir mandir runstatedir
+		libdir localedir mandir
 do
   eval ac_val=\$$ac_var
   # Remove trailing slashes.
@@ -1448,7 +1437,6 @@ Fine tuning of the installation directories:
   --sysconfdir=DIR        read-only single-machine data [PREFIX/etc]
   --sharedstatedir=DIR    modifiable architecture-independent data [PREFIX/com]
   --localstatedir=DIR     modifiable single-machine data [PREFIX/var]
-  --runstatedir=DIR       modifiable per-process data [LOCALSTATEDIR/run]
   --libdir=DIR            object code libraries [EPREFIX/lib]
   --includedir=DIR        C header files [PREFIX/include]
   --oldincludedir=DIR     C header files for non-gcc [/usr/include]
@@ -10303,6 +10291,7 @@ fi
 
 
 
+
 if test "x$ac_cv_env_PKG_CONFIG_set" != "xset"; then
 	if test -n "$ac_tool_prefix"; then
   # Extract the first word of "${ac_tool_prefix}pkg-config", so it can be a program name with args.
@@ -11561,7 +11550,7 @@ for ac_func in alarm accept4 setitimer getitimer bind_textdomain_codeset chown \
  posix_fallocate posix_fadvise posix_spawn posix_spawnp pread preadv preadv2 \
  pthread_condattr_setclock pthread_init pthread_kill putenv pwrite pwritev pwritev2 \
  readlink readlinkat readv realpath renameat \
- sem_open sem_timedwait sem_getvalue sem_unlink sendfile setegid seteuid \
+ sem_open sem_timedwait sem_getvalue sem_unlink sendfile setegid setenv seteuid \
  setgid sethostname \
  setlocale setregid setreuid setresuid setresgid setsid setpgid setpgrp setpriority setuid setvbuf \
  sched_get_priority_max sched_setaffinity sched_setscheduler sched_setparam \

configure.ac

@@ -3600,7 +3600,7 @@ AC_CHECK_FUNCS(alarm accept4 setitimer getitimer bind_textdomain_codeset chown \
  posix_fallocate posix_fadvise posix_spawn posix_spawnp pread preadv preadv2 \
  pthread_condattr_setclock pthread_init pthread_kill putenv pwrite pwritev pwritev2 \
  readlink readlinkat readv realpath renameat \
- sem_open sem_timedwait sem_getvalue sem_unlink sendfile setegid seteuid \
+ sem_open sem_timedwait sem_getvalue sem_unlink sendfile setegid setenv seteuid \
  setgid sethostname \
  setlocale setregid setreuid setresuid setresgid setsid setpgid setpgrp setpriority setuid setvbuf \
  sched_get_priority_max sched_setaffinity sched_setscheduler sched_setparam \

pyconfig.h.in

@@ -895,6 +895,9 @@
 /* Define to 1 if you have the `setegid' function. */
 #undef HAVE_SETEGID
 
+/* Define to 1 if you have the `setenv' function. */
+#undef HAVE_SETENV
+
 /* Define to 1 if you have the `seteuid' function. */
 #undef HAVE_SETEUID