/* Get the inheritable flag of the specified file descriptor.
Return 1 if the file descriptor can be inherited, 0 if it cannot,
raise an exception and return -1 on error. */
int
_Py_get_inheritable(int fd)
{
return get_inheritable(fd, 1);
}
static int
set_inheritable(int fd, int inheritable, int raise, int *atomic_flag_works)
{
#ifdef MS_WINDOWS
HANDLE handle;
DWORD flags;
#else
#if defined(HAVE_SYS_IOCTL_H) && defined(FIOCLEX) && defined(FIONCLEX)
static int ioctl_works = -1;
int request;
int err;
#endif
int flags;
int res;
#endif
/* atomic_flag_works can only be used to make the file descriptor
non-inheritable */
assert(!(atomic_flag_works != NULL && inheritable));
if (atomic_flag_works != NULL && !inheritable) {
if (*atomic_flag_works == -1) {
int inheritable = get_inheritable(fd, raise);
if (inheritable == -1)
return -1;
*atomic_flag_works = !inheritable;
}
if (*atomic_flag_works)
return 0;
}
#ifdef MS_WINDOWS
if (!_PyVerify_fd(fd)) {
if (raise)
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
handle = (HANDLE)_get_osfhandle(fd);
if (handle == INVALID_HANDLE_VALUE) {
if (raise)
PyErr_SetFromWindowsErr(0);
return -1;
}
if (inheritable)
flags = HANDLE_FLAG_INHERIT;
else
flags = 0;
if (!SetHandleInformation(handle, HANDLE_FLAG_INHERIT, flags)) {
if (raise)
PyErr_SetFromWindowsErr(0);
return -1;
}
return 0;
#else
#if defined(HAVE_SYS_IOCTL_H) && defined(FIOCLEX) && defined(FIONCLEX)
if (ioctl_works != 0) {
/* fast-path: ioctl() only requires one syscall */
if (inheritable)
request = FIONCLEX;
else
request = FIOCLEX;
err = ioctl(fd, request, NULL);
if (!err) {
ioctl_works = 1;
return 0;
}
if (errno != ENOTTY) {
if (raise)
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
else {
/* Issue #22258: Here, ENOTTY means "Inappropriate ioctl for
device". The ioctl is declared but not supported by the kernel.
Remember that ioctl() doesn't work. It is the case on
Illumos-based OS for example. */
ioctl_works = 0;
}
/* fallback to fcntl() if ioctl() does not work */
}
#endif
/* slow-path: fcntl() requires two syscalls */
flags = fcntl(fd, F_GETFD);
if (flags < 0) {
if (raise)
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
if (inheritable)
flags &= ~FD_CLOEXEC;
else
flags |= FD_CLOEXEC;
res = fcntl(fd, F_SETFD, flags);
if (res < 0) {
if (raise)
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
return 0;
#endif
}
static int
set_inheritable(int fd, int inheritable, int raise, int *atomic_flag_works)
{
#ifdef MS_WINDOWS
HANDLE handle;
DWORD flags;
#else
#if defined(HAVE_SYS_IOCTL_H) && defined(FIOCLEX) && defined(FIONCLEX)
static int ioctl_works = -1;
int request;
int err;
#endif
int flags, new_flags;
int res;
#endif
/* atomic_flag_works can only be used to make the file descriptor
non-inheritable */
assert(!(atomic_flag_works != NULL && inheritable));
if (atomic_flag_works != NULL && !inheritable) {
if (*atomic_flag_works == -1) {
int isInheritable = get_inheritable(fd, raise);
if (isInheritable == -1)
return -1;
*atomic_flag_works = !isInheritable;
}
if (*atomic_flag_works)
return 0;
}
#ifdef MS_WINDOWS
_Py_BEGIN_SUPPRESS_IPH
handle = (HANDLE)_get_osfhandle(fd);
_Py_END_SUPPRESS_IPH
if (handle == INVALID_HANDLE_VALUE) {
if (raise)
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
if (inheritable)
flags = HANDLE_FLAG_INHERIT;
else
flags = 0;
if (!SetHandleInformation(handle, HANDLE_FLAG_INHERIT, flags)) {
if (raise)
PyErr_SetFromWindowsErr(0);
return -1;
}
return 0;
#else
#if defined(HAVE_SYS_IOCTL_H) && defined(FIOCLEX) && defined(FIONCLEX)
if (ioctl_works != 0) {
/* fast-path: ioctl() only requires one syscall */
if (inheritable)
request = FIONCLEX;
else
request = FIOCLEX;
err = ioctl(fd, request, NULL);
if (!err) {
ioctl_works = 1;
return 0;
}
if (errno != ENOTTY && errno != EACCES) {
if (raise)
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
else {
/* Issue #22258: Here, ENOTTY means "Inappropriate ioctl for
device". The ioctl is declared but not supported by the kernel.
Remember that ioctl() doesn't work. It is the case on
Illumos-based OS for example.
Issue #27057: When SELinux policy disallows ioctl it will fail
with EACCES. While FIOCLEX is safe operation it may be
unavailable because ioctl was denied altogether.
This can be the case on Android. */
ioctl_works = 0;
}
/* fallback to fcntl() if ioctl() does not work */
}
#endif
/* slow-path: fcntl() requires two syscalls */
flags = fcntl(fd, F_GETFD);
if (flags < 0) {
if (raise)
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
if (inheritable) {
new_flags = flags & ~FD_CLOEXEC;
}
else {
new_flags = flags | FD_CLOEXEC;
}
if (new_flags == flags) {
/* FD_CLOEXEC flag already set/cleared: nothing to do */
return 0;
}
res = fcntl(fd, F_SETFD, new_flags);
if (res < 0) {
if (raise)
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
return 0;
#endif
}