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c2627d6eea
This PR adds the ability to enable the GIL if it was disabled at interpreter startup, and modifies the multi-phase module initialization path to enable the GIL when loading a module, unless that module's spec includes a slot indicating it can run safely without the GIL. PEP 703 called the constant for the slot `Py_mod_gil_not_used`; I went with `Py_MOD_GIL_NOT_USED` for consistency with gh-104148. A warning will be issued up to once per interpreter for the first GIL-using module that is loaded. If `-v` is given, a shorter message will be printed to stderr every time a GIL-using module is loaded (including the first one that issues a warning).
150 lines
3.6 KiB
C
150 lines
3.6 KiB
C
/*
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posixshmem - A Python extension that provides shm_open() and shm_unlink()
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*/
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// Need limited C API version 3.13 for Py_mod_gil
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#include "pyconfig.h" // Py_GIL_DISABLED
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#ifndef Py_GIL_DISABLED
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# define Py_LIMITED_API 0x030d0000
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#endif
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#include <Python.h>
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#include <string.h> // strlen()
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#include <errno.h> // EINTR
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#ifdef HAVE_SYS_MMAN_H
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# include <sys/mman.h> // shm_open(), shm_unlink()
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#endif
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/*[clinic input]
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module _posixshmem
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[clinic start generated code]*/
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/*[clinic end generated code: output=da39a3ee5e6b4b0d input=a416734e49164bf8]*/
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/*
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*
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* Module-level functions & meta stuff
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*
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*/
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#ifdef HAVE_SHM_OPEN
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/*[clinic input]
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_posixshmem.shm_open -> int
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path: unicode
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flags: int
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mode: int = 0o777
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# "shm_open(path, flags, mode=0o777)\n\n\
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Open a shared memory object. Returns a file descriptor (integer).
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[clinic start generated code]*/
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static int
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_posixshmem_shm_open_impl(PyObject *module, PyObject *path, int flags,
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int mode)
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/*[clinic end generated code: output=8d110171a4fa20df input=e83b58fa802fac25]*/
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{
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int fd;
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int async_err = 0;
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Py_ssize_t name_size;
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const char *name = PyUnicode_AsUTF8AndSize(path, &name_size);
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if (name == NULL) {
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return -1;
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}
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if (strlen(name) != (size_t)name_size) {
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PyErr_SetString(PyExc_ValueError, "embedded null character");
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return -1;
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}
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do {
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Py_BEGIN_ALLOW_THREADS
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fd = shm_open(name, flags, mode);
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Py_END_ALLOW_THREADS
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} while (fd < 0 && errno == EINTR && !(async_err = PyErr_CheckSignals()));
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if (fd < 0) {
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if (!async_err)
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PyErr_SetFromErrnoWithFilenameObject(PyExc_OSError, path);
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return -1;
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}
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return fd;
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}
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#endif /* HAVE_SHM_OPEN */
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#ifdef HAVE_SHM_UNLINK
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/*[clinic input]
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_posixshmem.shm_unlink
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path: unicode
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Remove a shared memory object (similar to unlink()).
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Remove a shared memory object name, and, once all processes have unmapped
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the object, de-allocates and destroys the contents of the associated memory
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region.
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[clinic start generated code]*/
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static PyObject *
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_posixshmem_shm_unlink_impl(PyObject *module, PyObject *path)
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/*[clinic end generated code: output=42f8b23d134b9ff5 input=8dc0f87143e3b300]*/
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{
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int rv;
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int async_err = 0;
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Py_ssize_t name_size;
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const char *name = PyUnicode_AsUTF8AndSize(path, &name_size);
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if (name == NULL) {
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return NULL;
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}
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if (strlen(name) != (size_t)name_size) {
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PyErr_SetString(PyExc_ValueError, "embedded null character");
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return NULL;
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}
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do {
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Py_BEGIN_ALLOW_THREADS
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rv = shm_unlink(name);
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Py_END_ALLOW_THREADS
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} while (rv < 0 && errno == EINTR && !(async_err = PyErr_CheckSignals()));
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if (rv < 0) {
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if (!async_err)
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PyErr_SetFromErrnoWithFilenameObject(PyExc_OSError, path);
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return NULL;
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}
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Py_RETURN_NONE;
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}
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#endif /* HAVE_SHM_UNLINK */
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#include "clinic/posixshmem.c.h"
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static PyMethodDef module_methods[ ] = {
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_POSIXSHMEM_SHM_OPEN_METHODDEF
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_POSIXSHMEM_SHM_UNLINK_METHODDEF
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{NULL} /* Sentinel */
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};
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static PyModuleDef_Slot module_slots[] = {
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{Py_mod_multiple_interpreters, Py_MOD_PER_INTERPRETER_GIL_SUPPORTED},
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{Py_mod_gil, Py_MOD_GIL_NOT_USED},
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{0, NULL}
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};
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static struct PyModuleDef _posixshmemmodule = {
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PyModuleDef_HEAD_INIT,
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.m_name = "_posixshmem",
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.m_doc = "POSIX shared memory module",
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.m_size = 0,
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.m_methods = module_methods,
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.m_slots = module_slots,
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};
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/* Module init function */
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PyMODINIT_FUNC
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PyInit__posixshmem(void)
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{
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return PyModuleDef_Init(&_posixshmemmodule);
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}
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