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issue10802: fallback to pipe+fcntl when the pipe2 syscall fails with errno ENOSYS.

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This commit is contained in:
Gregory P. Smith 2011-01-02 20:52:48 +00:00
parent e2dc082294
commit abcfcba61c
1 changed files with 30 additions and 18 deletions
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48
Modules/_posixsubprocess.c
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@ -415,27 +415,39 @@ subprocess_cloexec_pipe(PyObject *self, PyObject *noargs)
Py_BEGIN_ALLOW_THREADS
res = pipe2(fds, O_CLOEXEC);
Py_END_ALLOW_THREADS
#else
/* We hold the GIL which offers some protection from other code calling
* fork() before the CLOEXEC flags have been set but we can't guarantee
* anything without pipe2(). */
long oldflags;
if (res != 0 && errno == ENOSYS)
{
if (PyErr_WarnEx(
PyExc_RuntimeWarning,
"pipe2 set errno ENOSYS; falling "
"back to non-atomic pipe+fcntl.", 1) != 0) {
return NULL;
}
{
#endif
/* We hold the GIL which offers some protection from other code calling
* fork() before the CLOEXEC flags have been set but we can't guarantee
* anything without pipe2(). */
long oldflags;
res = pipe(fds);
res = pipe(fds);
if (res == 0) {
oldflags = fcntl(fds[0], F_GETFD, 0);
if (oldflags < 0) res = oldflags;
if (res == 0) {
oldflags = fcntl(fds[0], F_GETFD, 0);
if (oldflags < 0) res = oldflags;
}
if (res == 0)
res = fcntl(fds[0], F_SETFD, oldflags | FD_CLOEXEC);
if (res == 0) {
oldflags = fcntl(fds[1], F_GETFD, 0);
if (oldflags < 0) res = oldflags;
}
if (res == 0)
res = fcntl(fds[1], F_SETFD, oldflags | FD_CLOEXEC);
#ifdef HAVE_PIPE2
}
}
if (res == 0)
res = fcntl(fds[0], F_SETFD, oldflags | FD_CLOEXEC);
if (res == 0) {
oldflags = fcntl(fds[1], F_GETFD, 0);
if (oldflags < 0) res = oldflags;
}
if (res == 0)
res = fcntl(fds[1], F_SETFD, oldflags | FD_CLOEXEC);
#endif
if (res != 0)
return PyErr_SetFromErrno(PyExc_OSError);