bpo-37931: Fix crash on OSX re-initializing os.environ (GH-15428)

On most platforms, the `environ` symbol is accessible everywhere.

In a dylib on OSX, it's not easily accessible, you need to find it with
_NSGetEnviron.

The code was caching the *value* of environ. But a setenv() can change the value,
leaving garbage at the old value. Fix: don't cache the value of environ, just
read it every time.
This commit is contained in:
Benoit Hudson 2019-12-06 14:15:03 -05:00 committed by Victor Stinner
parent e76ee1a72b
commit 723f71abf7
3 changed files with 9 additions and 5 deletions

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@ -733,6 +733,7 @@ Miro Hrončok
Chiu-Hsiang Hsu
Chih-Hao Huang
Christian Hudon
Benoît Hudson
Lawrence Hudson
Michael Hudson
Jim Hugunin

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@ -0,0 +1,3 @@
Fixed a crash on OSX dynamic builds that occurred when re-initializing the
posix module after a Py_Finalize if the environment had changed since the
previous `import posix`. Patch by Benoît Hudson.

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@ -1402,7 +1402,6 @@ win32_get_reparse_tag(HANDLE reparse_point_handle, ULONG *reparse_tag)
** man environ(7).
*/
#include <crt_externs.h>
static char **environ;
#elif !defined(_MSC_VER) && (!defined(__WATCOMC__) || defined(__QNX__) || defined(__VXWORKS__))
extern char **environ;
#endif /* !_MSC_VER */
@ -1420,15 +1419,16 @@ convertenviron(void)
d = PyDict_New();
if (d == NULL)
return NULL;
#if defined(WITH_NEXT_FRAMEWORK) || (defined(__APPLE__) && defined(Py_ENABLE_SHARED))
if (environ == NULL)
environ = *_NSGetEnviron();
#endif
#ifdef MS_WINDOWS
/* _wenviron must be initialized in this way if the program is started
through main() instead of wmain(). */
_wgetenv(L"");
e = _wenviron;
#elif defined(WITH_NEXT_FRAMEWORK) || (defined(__APPLE__) && defined(Py_ENABLE_SHARED))
/* environ is not accessible as an extern in a shared object on OSX; use
_NSGetEnviron to resolve it. The value changes if you add environment
variables between calls to Py_Initialize, so don't cache the value. */
e = *_NSGetEnviron();
#else
e = environ;
#endif