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cpython/Modules/_multiprocessing/posixshmem.c

152 lines
3.6 KiB
C

/*
posixshmem - A Python extension that provides shm_open() and shm_unlink()
*/
// Need limited C API version 3.13 for Py_mod_gil
#include "pyconfig.h" // Py_GIL_DISABLED
#ifndef Py_GIL_DISABLED
# define Py_LIMITED_API 0x030d0000
#endif
#include <Python.h>
#include <string.h> // strlen()
#include <errno.h> // EINTR
#ifdef HAVE_SYS_MMAN_H
# include <sys/mman.h> // shm_open(), shm_unlink()
#endif
/*[clinic input]
module _posixshmem
[clinic start generated code]*/
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=a416734e49164bf8]*/
/*
*
* Module-level functions & meta stuff
*
*/
#ifdef HAVE_SHM_OPEN
/*[clinic input]
_posixshmem.shm_open -> int
path: unicode
flags: int
mode: int = 0o777
# "shm_open(path, flags, mode=0o777)\n\n\
Open a shared memory object. Returns a file descriptor (integer).
[clinic start generated code]*/
static int
_posixshmem_shm_open_impl(PyObject *module, PyObject *path, int flags,
int mode)
/*[clinic end generated code: output=8d110171a4fa20df input=e83b58fa802fac25]*/
{
int fd;
int async_err = 0;
Py_ssize_t name_size;
const char *name = PyUnicode_AsUTF8AndSize(path, &name_size);
if (name == NULL) {
return -1;
}
if (strlen(name) != (size_t)name_size) {
PyErr_SetString(PyExc_ValueError, "embedded null character");
return -1;
}
do {
Py_BEGIN_ALLOW_THREADS
fd = shm_open(name, flags, mode);
Py_END_ALLOW_THREADS
} while (fd < 0 && errno == EINTR && !(async_err = PyErr_CheckSignals()));
if (fd < 0) {
if (!async_err)
PyErr_SetFromErrnoWithFilenameObject(PyExc_OSError, path);
return -1;
}
return fd;
}
#endif /* HAVE_SHM_OPEN */
#ifdef HAVE_SHM_UNLINK
/*[clinic input]
_posixshmem.shm_unlink
path: unicode
/
Remove a shared memory object (similar to unlink()).
Remove a shared memory object name, and, once all processes have unmapped
the object, de-allocates and destroys the contents of the associated memory
region.
[clinic start generated code]*/
static PyObject *
_posixshmem_shm_unlink_impl(PyObject *module, PyObject *path)
/*[clinic end generated code: output=42f8b23d134b9ff5 input=298369d013dcad63]*/
{
int rv;
int async_err = 0;
Py_ssize_t name_size;
const char *name = PyUnicode_AsUTF8AndSize(path, &name_size);
if (name == NULL) {
return NULL;
}
if (strlen(name) != (size_t)name_size) {
PyErr_SetString(PyExc_ValueError, "embedded null character");
return NULL;
}
do {
Py_BEGIN_ALLOW_THREADS
rv = shm_unlink(name);
Py_END_ALLOW_THREADS
} while (rv < 0 && errno == EINTR && !(async_err = PyErr_CheckSignals()));
if (rv < 0) {
if (!async_err)
PyErr_SetFromErrnoWithFilenameObject(PyExc_OSError, path);
return NULL;
}
Py_RETURN_NONE;
}
#endif /* HAVE_SHM_UNLINK */
#include "clinic/posixshmem.c.h"
static PyMethodDef module_methods[ ] = {
_POSIXSHMEM_SHM_OPEN_METHODDEF
_POSIXSHMEM_SHM_UNLINK_METHODDEF
{NULL} /* Sentinel */
};
static PyModuleDef_Slot module_slots[] = {
{Py_mod_multiple_interpreters, Py_MOD_PER_INTERPRETER_GIL_SUPPORTED},
{Py_mod_gil, Py_MOD_GIL_NOT_USED},
{0, NULL}
};
static struct PyModuleDef _posixshmemmodule = {
PyModuleDef_HEAD_INIT,
.m_name = "_posixshmem",
.m_doc = "POSIX shared memory module",
.m_size = 0,
.m_methods = module_methods,
.m_slots = module_slots,
};
/* Module init function */
PyMODINIT_FUNC
PyInit__posixshmem(void)
{
return PyModuleDef_Init(&_posixshmemmodule);
}