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3be7498d24
cpython/Modules/_dbmmodule.c
Brett Simmers c2627d6eea
gh-116322: Add Py_mod_gil module slot (#116882) 
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).
2024-05-03 11:30:55 -04:00

639 lines
16 KiB
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/* DBM module using dictionary interface */
// clinic/_dbmmodule.c.h uses internal pycore_modsupport.h API
#ifndef Py_BUILD_CORE_BUILTIN
# define Py_BUILD_CORE_MODULE 1
#endif
#include "Python.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
/* Some Linux systems install gdbm/ndbm.h, but not ndbm.h. This supports
* whichever configure was able to locate.
*/
#if defined(USE_GDBM_COMPAT)
#ifdef HAVE_GDBM_NDBM_H
#include <gdbm/ndbm.h>
#elif HAVE_GDBM_DASH_NDBM_H
#include <gdbm-ndbm.h>
#else
#error "No gdbm/ndbm.h or gdbm-ndbm.h available"
#endif
static const char which_dbm[] = "GNU gdbm";
#elif defined(USE_NDBM)
#include <ndbm.h>
static const char which_dbm[] = "GNU gdbm";
#elif defined(USE_BERKDB)
#ifndef DB_DBM_HSEARCH
#define DB_DBM_HSEARCH 1
#endif
#include <db.h>
static const char which_dbm[] = "Berkeley DB";
#else
#error "No ndbm.h available!"
#endif
typedef struct {
PyTypeObject *dbm_type;
PyObject *dbm_error;
} _dbm_state;
static inline _dbm_state*
get_dbm_state(PyObject *module)
{
void *state = PyModule_GetState(module);
assert(state != NULL);
return (_dbm_state *)state;
}
/*[clinic input]
module _dbm
class _dbm.dbm "dbmobject *" "&Dbmtype"
[clinic start generated code]*/
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=9b1aa8756d16150e]*/
typedef struct {
PyObject_HEAD
int flags;
int di_size; /* -1 means recompute */
DBM *di_dbm;
} dbmobject;
#include "clinic/_dbmmodule.c.h"
#define check_dbmobject_open(v, err) \
if ((v)->di_dbm == NULL) { \
PyErr_SetString(err, "DBM object has already been closed"); \
return NULL; \
}
static PyObject *
newdbmobject(_dbm_state *state, const char *file, int flags, int mode)
{
dbmobject *dp = PyObject_GC_New(dbmobject, state->dbm_type);
if (dp == NULL) {
return NULL;
}
dp->di_size = -1;
dp->flags = flags;
PyObject_GC_Track(dp);
/* See issue #19296 */
if ( (dp->di_dbm = dbm_open((char *)file, flags, mode)) == 0 ) {
PyErr_SetFromErrnoWithFilename(state->dbm_error, file);
Py_DECREF(dp);
return NULL;
}
return (PyObject *)dp;
}
/* Methods */
static int
dbm_traverse(dbmobject *dp, visitproc visit, void *arg)
{
Py_VISIT(Py_TYPE(dp));
return 0;
}
static void
dbm_dealloc(dbmobject *dp)
{
PyObject_GC_UnTrack(dp);
if (dp->di_dbm) {
dbm_close(dp->di_dbm);
}
PyTypeObject *tp = Py_TYPE(dp);
tp->tp_free(dp);
Py_DECREF(tp);
}
static Py_ssize_t
dbm_length(dbmobject *dp)
{
_dbm_state *state = PyType_GetModuleState(Py_TYPE(dp));
assert(state != NULL);
if (dp->di_dbm == NULL) {
PyErr_SetString(state->dbm_error, "DBM object has already been closed");
return -1;
}
if ( dp->di_size < 0 ) {
datum key;
int size;
size = 0;
for ( key=dbm_firstkey(dp->di_dbm); key.dptr;
key = dbm_nextkey(dp->di_dbm))
size++;
dp->di_size = size;
}
return dp->di_size;
}
static int
dbm_bool(dbmobject *dp)
{
_dbm_state *state = PyType_GetModuleState(Py_TYPE(dp));
assert(state != NULL);
if (dp->di_dbm == NULL) {
PyErr_SetString(state->dbm_error, "DBM object has already been closed");
return -1;
}
if (dp->di_size > 0) {
/* Known non-zero size. */
return 1;
}
if (dp->di_size == 0) {
/* Known zero size. */
return 0;
}
/* Unknown size. Ensure DBM object has an entry. */
datum key = dbm_firstkey(dp->di_dbm);
if (key.dptr == NULL) {
/* Empty. Cache this fact. */
dp->di_size = 0;
return 0;
}
/* Non-empty. Don't cache the length since we don't know. */
return 1;
}
static PyObject *
dbm_subscript(dbmobject *dp, PyObject *key)
{
datum drec, krec;
Py_ssize_t tmp_size;
_dbm_state *state = PyType_GetModuleState(Py_TYPE(dp));
assert(state != NULL);
if (!PyArg_Parse(key, "s#", &krec.dptr, &tmp_size)) {
return NULL;
}
krec.dsize = tmp_size;
check_dbmobject_open(dp, state->dbm_error);
drec = dbm_fetch(dp->di_dbm, krec);
if ( drec.dptr == 0 ) {
PyErr_SetObject(PyExc_KeyError, key);
return NULL;
}
if ( dbm_error(dp->di_dbm) ) {
dbm_clearerr(dp->di_dbm);
PyErr_SetString(state->dbm_error, "");
return NULL;
}
return PyBytes_FromStringAndSize(drec.dptr, drec.dsize);
}
static int
dbm_ass_sub(dbmobject *dp, PyObject *v, PyObject *w)
{
datum krec, drec;
Py_ssize_t tmp_size;
if ( !PyArg_Parse(v, "s#", &krec.dptr, &tmp_size) ) {
PyErr_SetString(PyExc_TypeError,
"dbm mappings have bytes or string keys only");
return -1;
}
_dbm_state *state = PyType_GetModuleState(Py_TYPE(dp));
assert(state != NULL);
krec.dsize = tmp_size;
if (dp->di_dbm == NULL) {
PyErr_SetString(state->dbm_error, "DBM object has already been closed");
return -1;
}
dp->di_size = -1;
if (w == NULL) {
if ( dbm_delete(dp->di_dbm, krec) < 0 ) {
dbm_clearerr(dp->di_dbm);
/* we might get a failure for reasons like file corrupted,
but we are not able to distinguish it */
if (dp->flags & O_RDWR) {
PyErr_SetObject(PyExc_KeyError, v);
}
else {
PyErr_SetString(state->dbm_error, "cannot delete item from database");
}
return -1;
}
} else {
if ( !PyArg_Parse(w, "s#", &drec.dptr, &tmp_size) ) {
PyErr_SetString(PyExc_TypeError,
"dbm mappings have bytes or string elements only");
return -1;
}
drec.dsize = tmp_size;
if ( dbm_store(dp->di_dbm, krec, drec, DBM_REPLACE) < 0 ) {
dbm_clearerr(dp->di_dbm);
PyErr_SetString(state->dbm_error,
"cannot add item to database");
return -1;
}
}
if ( dbm_error(dp->di_dbm) ) {
dbm_clearerr(dp->di_dbm);
PyErr_SetString(state->dbm_error, "");
return -1;
}
return 0;
}
/*[clinic input]
_dbm.dbm.close
Close the database.
[clinic start generated code]*/
static PyObject *
_dbm_dbm_close_impl(dbmobject *self)
/*[clinic end generated code: output=c8dc5b6709600b86 input=046db72377d51be8]*/
{
if (self->di_dbm) {
dbm_close(self->di_dbm);
}
self->di_dbm = NULL;
Py_RETURN_NONE;
}
/*[clinic input]
_dbm.dbm.keys
cls: defining_class
Return a list of all keys in the database.
[clinic start generated code]*/
static PyObject *
_dbm_dbm_keys_impl(dbmobject *self, PyTypeObject *cls)
/*[clinic end generated code: output=f2a593b3038e5996 input=d3706a28fc051097]*/
{
PyObject *v, *item;
datum key;
int err;
_dbm_state *state = PyType_GetModuleState(cls);
assert(state != NULL);
check_dbmobject_open(self, state->dbm_error);
v = PyList_New(0);
if (v == NULL) {
return NULL;
}
for (key = dbm_firstkey(self->di_dbm); key.dptr;
key = dbm_nextkey(self->di_dbm)) {
item = PyBytes_FromStringAndSize(key.dptr, key.dsize);
if (item == NULL) {
Py_DECREF(v);
return NULL;
}
err = PyList_Append(v, item);
Py_DECREF(item);
if (err != 0) {
Py_DECREF(v);
return NULL;
}
}
return v;
}
static int
dbm_contains(PyObject *self, PyObject *arg)
{
dbmobject *dp = (dbmobject *)self;
datum key, val;
Py_ssize_t size;
_dbm_state *state = PyType_GetModuleState(Py_TYPE(dp));
assert(state != NULL);
if ((dp)->di_dbm == NULL) {
PyErr_SetString(state->dbm_error,
"DBM object has already been closed");
return -1;
}
if (PyUnicode_Check(arg)) {
key.dptr = (char *)PyUnicode_AsUTF8AndSize(arg, &size);
key.dsize = size;
if (key.dptr == NULL)
return -1;
}
else if (!PyBytes_Check(arg)) {
PyErr_Format(PyExc_TypeError,
"dbm key must be bytes or string, not %.100s",
Py_TYPE(arg)->tp_name);
return -1;
}
else {
key.dptr = PyBytes_AS_STRING(arg);
key.dsize = PyBytes_GET_SIZE(arg);
}
val = dbm_fetch(dp->di_dbm, key);
return val.dptr != NULL;
}
/*[clinic input]
_dbm.dbm.get
cls: defining_class
key: str(accept={str, robuffer}, zeroes=True)
default: object = None
/
Return the value for key if present, otherwise default.
[clinic start generated code]*/
static PyObject *
_dbm_dbm_get_impl(dbmobject *self, PyTypeObject *cls, const char *key,
Py_ssize_t key_length, PyObject *default_value)
/*[clinic end generated code: output=b4e55f8b6d482bc4 input=66b993b8349fa8c1]*/
{
datum dbm_key, val;
_dbm_state *state = PyType_GetModuleState(cls);
assert(state != NULL);
dbm_key.dptr = (char *)key;
dbm_key.dsize = key_length;
check_dbmobject_open(self, state->dbm_error);
val = dbm_fetch(self->di_dbm, dbm_key);
if (val.dptr != NULL) {
return PyBytes_FromStringAndSize(val.dptr, val.dsize);
}
return Py_NewRef(default_value);
}
/*[clinic input]
_dbm.dbm.setdefault
cls: defining_class
key: str(accept={str, robuffer}, zeroes=True)
default: object(c_default="NULL") = b''
/
Return the value for key if present, otherwise default.
If key is not in the database, it is inserted with default as the value.
[clinic start generated code]*/
static PyObject *
_dbm_dbm_setdefault_impl(dbmobject *self, PyTypeObject *cls, const char *key,
Py_ssize_t key_length, PyObject *default_value)
/*[clinic end generated code: output=9c2f6ea6d0fb576c input=126a3ff15c5f8232]*/
{
datum dbm_key, val;
Py_ssize_t tmp_size;
_dbm_state *state = PyType_GetModuleState(cls);
assert(state != NULL);
dbm_key.dptr = (char *)key;
dbm_key.dsize = key_length;
check_dbmobject_open(self, state->dbm_error);
val = dbm_fetch(self->di_dbm, dbm_key);
if (val.dptr != NULL) {
return PyBytes_FromStringAndSize(val.dptr, val.dsize);
}
if (default_value == NULL) {
default_value = PyBytes_FromStringAndSize(NULL, 0);
if (default_value == NULL) {
return NULL;
}
val.dptr = NULL;
val.dsize = 0;
}
else {
if ( !PyArg_Parse(default_value, "s#", &val.dptr, &tmp_size) ) {
PyErr_SetString(PyExc_TypeError,
"dbm mappings have bytes or string elements only");
return NULL;
}
val.dsize = tmp_size;
Py_INCREF(default_value);
}
if (dbm_store(self->di_dbm, dbm_key, val, DBM_INSERT) < 0) {
dbm_clearerr(self->di_dbm);
PyErr_SetString(state->dbm_error, "cannot add item to database");
Py_DECREF(default_value);
return NULL;
}
return default_value;
}
/*[clinic input]
_dbm.dbm.clear
cls: defining_class
/
Remove all items from the database.
[clinic start generated code]*/
static PyObject *
_dbm_dbm_clear_impl(dbmobject *self, PyTypeObject *cls)
/*[clinic end generated code: output=8d126b9e1d01a434 input=43aa6ca1acb7f5f5]*/
{
_dbm_state *state = PyType_GetModuleState(cls);
assert(state != NULL);
check_dbmobject_open(self, state->dbm_error);
datum key;
// Invalidate cache
self->di_size = -1;
while (1) {
key = dbm_firstkey(self->di_dbm);
if (key.dptr == NULL) {
break;
}
if (dbm_delete(self->di_dbm, key) < 0) {
dbm_clearerr(self->di_dbm);
PyErr_SetString(state->dbm_error, "cannot delete item from database");
return NULL;
}
}
Py_RETURN_NONE;
}
static PyObject *
dbm__enter__(PyObject *self, PyObject *args)
{
return Py_NewRef(self);
}
static PyObject *
dbm__exit__(PyObject *self, PyObject *args)
{
return _dbm_dbm_close_impl((dbmobject *)self);
}
static PyMethodDef dbm_methods[] = {
_DBM_DBM_CLOSE_METHODDEF
_DBM_DBM_KEYS_METHODDEF
_DBM_DBM_GET_METHODDEF
_DBM_DBM_SETDEFAULT_METHODDEF
_DBM_DBM_CLEAR_METHODDEF
{"__enter__", dbm__enter__, METH_NOARGS, NULL},
{"__exit__", dbm__exit__, METH_VARARGS, NULL},
{NULL, NULL} /* sentinel */
};
static PyType_Slot dbmtype_spec_slots[] = {
{Py_tp_dealloc, dbm_dealloc},
{Py_tp_traverse, dbm_traverse},
{Py_tp_methods, dbm_methods},
{Py_sq_contains, dbm_contains},
{Py_mp_length, dbm_length},
{Py_mp_subscript, dbm_subscript},
{Py_mp_ass_subscript, dbm_ass_sub},
{Py_nb_bool, dbm_bool},
{0, 0}
};
static PyType_Spec dbmtype_spec = {
.name = "_dbm.dbm",
.basicsize = sizeof(dbmobject),
// Calling PyType_GetModuleState() on a subclass is not safe.
// dbmtype_spec does not have Py_TPFLAGS_BASETYPE flag
// which prevents to create a subclass.
// So calling PyType_GetModuleState() in this file is always safe.
.flags = (Py_TPFLAGS_DEFAULT | Py_TPFLAGS_DISALLOW_INSTANTIATION |
Py_TPFLAGS_HAVE_GC | Py_TPFLAGS_IMMUTABLETYPE),
.slots = dbmtype_spec_slots,
};
/* ----------------------------------------------------------------- */
/*[clinic input]
_dbm.open as dbmopen
filename: object
The filename to open.
flags: str="r"
How to open the file. "r" for reading, "w" for writing, etc.
mode: int(py_default="0o666") = 0o666
If creating a new file, the mode bits for the new file
(e.g. os.O_RDWR).
/
Return a database object.
[clinic start generated code]*/
static PyObject *
dbmopen_impl(PyObject *module, PyObject *filename, const char *flags,
int mode)
/*[clinic end generated code: output=9527750f5df90764 input=d8cf50a9f81218c8]*/
{
int iflags;
_dbm_state *state = get_dbm_state(module);
assert(state != NULL);
if (strcmp(flags, "r") == 0) {
iflags = O_RDONLY;
}
else if (strcmp(flags, "w") == 0) {
iflags = O_RDWR;
}
else if (strcmp(flags, "rw") == 0) {
/* Backward compatibility */
iflags = O_RDWR|O_CREAT;
}
else if (strcmp(flags, "c") == 0) {
iflags = O_RDWR|O_CREAT;
}
else if (strcmp(flags, "n") == 0) {
iflags = O_RDWR|O_CREAT|O_TRUNC;
}
else {
PyErr_SetString(state->dbm_error,
"arg 2 to open should be 'r', 'w', 'c', or 'n'");
return NULL;
}
PyObject *filenamebytes;
if (!PyUnicode_FSConverter(filename, &filenamebytes)) {
return NULL;
}
const char *name = PyBytes_AS_STRING(filenamebytes);
PyObject *self = newdbmobject(state, name, iflags, mode);
Py_DECREF(filenamebytes);
return self;
}
static PyMethodDef dbmmodule_methods[] = {
DBMOPEN_METHODDEF
{ 0, 0 },
};
static int
_dbm_exec(PyObject *module)
{
_dbm_state *state = get_dbm_state(module);
state->dbm_type = (PyTypeObject *)PyType_FromModuleAndSpec(module,
&dbmtype_spec, NULL);
if (state->dbm_type == NULL) {
return -1;
}
state->dbm_error = PyErr_NewException("_dbm.error", PyExc_OSError, NULL);
if (state->dbm_error == NULL) {
return -1;
}
if (PyModule_AddStringConstant(module, "library", which_dbm) < 0) {
return -1;
}
if (PyModule_AddType(module, (PyTypeObject *)state->dbm_error) < 0) {
return -1;
}
return 0;
}
static int
_dbm_module_traverse(PyObject *module, visitproc visit, void *arg)
{
_dbm_state *state = get_dbm_state(module);
Py_VISIT(state->dbm_error);
Py_VISIT(state->dbm_type);
return 0;
}
static int
_dbm_module_clear(PyObject *module)
{
_dbm_state *state = get_dbm_state(module);
Py_CLEAR(state->dbm_error);
Py_CLEAR(state->dbm_type);
return 0;
}
static void
_dbm_module_free(void *module)
{
_dbm_module_clear((PyObject *)module);
}
static PyModuleDef_Slot _dbmmodule_slots[] = {
{Py_mod_exec, _dbm_exec},
{Py_mod_multiple_interpreters, Py_MOD_PER_INTERPRETER_GIL_SUPPORTED},
{Py_mod_gil, Py_MOD_GIL_NOT_USED},
{0, NULL}
};
static struct PyModuleDef _dbmmodule = {
PyModuleDef_HEAD_INIT,
.m_name = "_dbm",
.m_size = sizeof(_dbm_state),
.m_methods = dbmmodule_methods,
.m_slots = _dbmmodule_slots,
.m_traverse = _dbm_module_traverse,
.m_clear = _dbm_module_clear,
.m_free = _dbm_module_free,
};
PyMODINIT_FUNC
PyInit__dbm(void)
{
return PyModuleDef_Init(&_dbmmodule);
}
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