python/py_tdb.c

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/* 
   Python wrappers for TDB module

   Copyright (C) Tim Potter, 2002-2003
   
     ** NOTE! The following LGPL license applies to the tdb python
     ** scripting library. This does NOT imply that all of Samba is 
     ** released under the LGPL
   
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.

   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.
   
   You should have received a copy of the GNU Lesser General Public
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include "includes.h"

/* This symbol is used in both includes.h and Python.h which causes an
   annoying compiler warning. */

#ifdef HAVE_FSTAT
#undef HAVE_FSTAT
#endif

#include "Python.h"

/* Tdb exception */

PyObject *py_tdb_error;

/* tdb handle object */

typedef struct {
        PyObject_HEAD
        TDB_CONTEXT *tdb;
} tdb_hnd_object;

PyTypeObject tdb_hnd_type;
     
PyObject *new_tdb_hnd_object(TDB_CONTEXT *tdb)
{
        tdb_hnd_object *obj;

        obj = PyObject_New(tdb_hnd_object, &tdb_hnd_type);
        obj->tdb = tdb;

        return (PyObject *)obj;
}

PyObject *py_tdb_close(PyObject *self, PyObject *args)
{
        tdb_hnd_object *obj;

        if (!PyArg_ParseTuple(args, "O!", &tdb_hnd_type, &obj))
                return NULL;

        if (tdb_close(obj->tdb) == -1) {
                obj->tdb = NULL;
                PyErr_SetString(py_tdb_error, strerror(errno));
                return NULL;
        }

        obj->tdb = NULL;

        Py_INCREF(Py_None);
        return Py_None;
}

PyObject *py_tdb_open(PyObject *self, PyObject *args, PyObject *kw)
{
        static char *kwlist[] = { "name", "hash_size", "tdb_flags",
                                  "open_flags", "mode", NULL };
        char *name;
        int hash_size = 0, flags = TDB_DEFAULT, open_flags = -1, open_mode = 0600;      
        TDB_CONTEXT *tdb;

        if (!PyArg_ParseTupleAndKeywords(
                    args, kw, "s|iiii", kwlist, &name, &hash_size, &flags,
                    &open_flags, &open_mode))
                return NULL;

        /* Default open_flags to read/write */

        if (open_flags == -1) {
                if (access(name, W_OK) == -1)
                        open_flags = O_RDONLY;
                else
                        open_flags = O_RDWR;
        }

        if (!(tdb = tdb_open(name, hash_size, flags, open_flags, open_mode))) {
                PyErr_SetString(py_tdb_error, strerror(errno));
                return NULL;
        }

        return new_tdb_hnd_object(tdb);
}

/*
 * Allow a tdb to act as a python mapping (dictionary)
 */

static int tdb_traverse_count(TDB_CONTEXT *tdb, TDB_DATA key, TDB_DATA value,
                              void *state)
{
        /* Do nothing - tdb_traverse will return the number of records
           traversed. */

        return 0;
}

static int tdb_hnd_length(tdb_hnd_object *obj)
{
        int result;

        result = tdb_traverse(obj->tdb, tdb_traverse_count, NULL);

        return result;
}

static PyObject *tdb_hnd_subscript(tdb_hnd_object *obj, PyObject *key)
{
        TDB_DATA drec, krec;
        PyObject *result;

        if (!PyArg_Parse(key, "s#", &krec.dptr, &krec.dsize))
                return NULL;

        drec = tdb_fetch(obj->tdb, krec);

        if (!drec.dptr) {
                PyErr_SetString(PyExc_KeyError,
                                PyString_AsString(key));
                return NULL;
        }

        result = PyString_FromStringAndSize(drec.dptr, drec.dsize);
        free(drec.dptr);

        return result;
}
        
static int tdb_ass_subscript(tdb_hnd_object *obj, PyObject *key, PyObject *value)
{
        TDB_DATA krec, drec;

        if (!PyArg_Parse(key, "s#", &krec.dptr, &krec.dsize)) {
                PyErr_SetString(PyExc_TypeError,
                                "tdb mappings have string indices only");
                return -1;
        }

        if (!obj->tdb) {
                PyErr_SetString(
                        py_tdb_error, "tdb object has been closed"); 
                return -1; 
        }

        if (!value) {

                /* Delete value */

                if (tdb_delete(obj->tdb, krec) == -1) {
                        PyErr_SetString(PyExc_KeyError,
                                        PyString_AsString(value));
                        return -1;
                }

        } else {

                /* Set value */

                if (!PyArg_Parse(value, "s#", &drec.dptr, &drec.dsize)) {
                        PyErr_SetString(PyExc_TypeError,
                                    "tdb mappings have string elements only");
                        return -1;
                }

                errno = 0;

                if (tdb_store(obj->tdb, krec, drec, 0) < 0 ) {
                        if (errno != 0)
                                PyErr_SetFromErrno(py_tdb_error);
                        else
                                PyErr_SetString(
                                        py_tdb_error, 
                                        (char *)tdb_errorstr(obj->tdb));

                        return -1;
                }
        }

        return 0;
} 

static PyMappingMethods tdb_mapping = {
        (inquiry) tdb_hnd_length,
        (binaryfunc) tdb_hnd_subscript,
        (objobjargproc) tdb_ass_subscript
};

/*
 * Utility methods
 */

/* Return non-zero if a given key exists in the tdb */

PyObject *py_tdb_hnd_has_key(PyObject *self, PyObject *args)
{
        tdb_hnd_object *obj = (tdb_hnd_object *)self;
        TDB_DATA key;

        if (!PyArg_ParseTuple(args, "s#", &key.dptr, &key.dsize))
                return NULL;

        if (!obj->tdb) {
                PyErr_SetString(
                        py_tdb_error, "tdb object has been closed"); 
                return NULL;
        }       

        return PyInt_FromLong(tdb_exists(obj->tdb, key));
}

/* Return a list of keys in the tdb */

static int tdb_traverse_keys(TDB_CONTEXT *tdb, TDB_DATA key, TDB_DATA value,
                             void *state)
{
        PyObject *key_list = (PyObject *)state;

        PyList_Append(key_list, 
                      PyString_FromStringAndSize(key.dptr, key.dsize));

        return 0;
}

PyObject *py_tdb_hnd_keys(PyObject *self, PyObject *args)
{
        tdb_hnd_object *obj = (tdb_hnd_object *)self;
        PyObject *key_list = PyList_New(0);

        if (!obj->tdb) {
                PyErr_SetString(py_tdb_error, "tdb object has been closed"); 
                return NULL;
        }       

        if (tdb_traverse(obj->tdb, tdb_traverse_keys, key_list) == -1) {
                PyErr_SetString(py_tdb_error, "error traversing tdb");
                Py_DECREF(key_list);
                return NULL;
        }

        return key_list;        
}

PyObject *py_tdb_hnd_first_key(PyObject *self, PyObject *args)
{
        tdb_hnd_object *obj = (tdb_hnd_object *)self;
        TDB_DATA key;

        if (!obj->tdb) {
                PyErr_SetString(py_tdb_error, "tdb object has been closed"); 
                return NULL;
        }       

        key = tdb_firstkey(obj->tdb);

        return Py_BuildValue("s#", key.dptr, key.dsize);
}

PyObject *py_tdb_hnd_next_key(PyObject *self, PyObject *py_oldkey)
{
        tdb_hnd_object *obj = (tdb_hnd_object *)self;
        TDB_DATA key, oldkey;

        if (!obj->tdb) {
                PyErr_SetString(py_tdb_error, "tdb object has been closed"); 
                return NULL;
        }       

        if (!PyArg_Parse(py_oldkey, "s#", &oldkey.dptr, &oldkey.dsize))
                return NULL;

        key = tdb_nextkey(obj->tdb, oldkey);

        return Py_BuildValue("s#", key.dptr, key.dsize);
}

/*
 * Locking routines
 */

PyObject *py_tdb_hnd_lock_all(PyObject *self, PyObject *args)
{
        tdb_hnd_object *obj = (tdb_hnd_object *)self;
        int result;

        if (!obj->tdb) {
                PyErr_SetString(py_tdb_error, "tdb object has been closed"); 
                return NULL;
        }       

        result = tdb_lockall(obj->tdb);

        return PyInt_FromLong(result != -1);
}

PyObject *py_tdb_hnd_unlock_all(PyObject *self, PyObject *args)
{
        tdb_hnd_object *obj = (tdb_hnd_object *)self;

        if (!obj->tdb) {
                PyErr_SetString(py_tdb_error, "tdb object has been closed"); 
                return NULL;
        }       

        tdb_unlockall(obj->tdb);

        Py_INCREF(Py_None);
        return Py_None;
}

/* Return an array of keys from a python object which must be a string or a
   list of strings. */

static BOOL make_lock_list(PyObject *py_keys, TDB_DATA **keys, int *num_keys)
{
        /* Are we a list or a string? */

        if (!PyList_Check(py_keys) && !PyString_Check(py_keys)) {
                PyErr_SetString(PyExc_TypeError, "arg must be list of string");
                return False;
        }

        if (PyList_Check(py_keys)) {
                int i;

                /* Turn python list into array of keys */
                
                *num_keys = PyList_Size(py_keys);
                *keys = (TDB_DATA *)SMB_XMALLOC_ARRAY(TDB_DATA, (*num_keys));
                
                for (i = 0; i < *num_keys; i++) {
                        PyObject *key = PyList_GetItem(py_keys, i);
                        
                        if (!PyString_Check(key)) {
                                PyErr_SetString(
                                        PyExc_TypeError,
                                        "list elements must be strings");
                                return False;
                        }

                        PyArg_Parse(key, "s#", &(*keys)[i].dptr, 
                                    &(*keys)[i].dsize);
                }

        } else {

                /* Turn python string into a single key */

                *keys = (TDB_DATA *)SMB_XMALLOC_P(TDB_DATA);
                *num_keys = 1;
                PyArg_Parse(py_keys, "s#", &(*keys)->dptr, &(*keys)->dsize);
        }

        return True;
}

/*
 * tdb traversal
 */

struct traverse_info {
        PyObject *callback;
        PyObject *state;
};

static int tdb_traverse_traverse(TDB_CONTEXT *tdb, TDB_DATA key, TDB_DATA value,
                                 void *state)
{
        struct traverse_info *info = state;
        PyObject *arglist, *py_result;
        int result;

        arglist = Py_BuildValue("(s#s#O)", key.dptr, key.dsize, value.dptr,
                                value.dsize, info->state);

        py_result = PyEval_CallObject(info->callback, arglist);

        Py_DECREF(arglist);
        
        if (!PyInt_Check(py_result)) {
                result = 1;     /* Hmm - non-integer object returned by callback */
                goto done;
        }

        result = PyInt_AsLong(py_result);

done:
        Py_DECREF(py_result);
        return result;
}

PyObject *py_tdb_hnd_traverse(PyObject *self, PyObject *args, PyObject *kw)
{
        tdb_hnd_object *obj = (tdb_hnd_object *)self;
        static char *kwlist[] = { "traverse_fn", "state", NULL };
        PyObject *state = Py_None, *callback;
        struct traverse_info info;
        int result;

        if (!PyArg_ParseTupleAndKeywords(
                    args, kw, "O|O", kwlist, &callback, &state))
                return NULL;

        if (!PyCallable_Check(callback)) {
                PyErr_SetString(PyExc_TypeError, "parameter must be callable");
                return NULL;
        }

        Py_INCREF(callback);
        Py_INCREF(state);

        info.callback = callback;
        info.state = state;

        result = tdb_traverse(obj->tdb, tdb_traverse_traverse, &info);

        Py_DECREF(callback);
        Py_DECREF(state);

        return PyInt_FromLong(result);
}

PyObject *py_tdb_hnd_chainlock(PyObject *self, PyObject *args)
{
        tdb_hnd_object *obj = (tdb_hnd_object *)self;
        TDB_DATA key;
        int result;

        if (!obj->tdb) {
                PyErr_SetString(py_tdb_error, "tdb object has been closed"); 
                return NULL;
        }       

        if (!PyArg_ParseTuple(args, "s#", &key.dptr, &key.dsize))
                return NULL;

        result = tdb_chainlock(obj->tdb, key);

        return PyInt_FromLong(result != -1);
}

PyObject *py_tdb_hnd_chainunlock(PyObject *self, PyObject *args)
{
        tdb_hnd_object *obj = (tdb_hnd_object *)self;
        TDB_DATA key;
        int result;

        if (!obj->tdb) {
                PyErr_SetString(py_tdb_error, "tdb object has been closed"); 
                return NULL;
        }       

        if (!PyArg_ParseTuple(args, "s#", &key.dptr, &key.dsize))
                return NULL;

        result = tdb_chainunlock(obj->tdb, key);

        return PyInt_FromLong(result != -1);
}

PyObject *py_tdb_hnd_lock_bystring(PyObject *self, PyObject *args)
{
        tdb_hnd_object *obj = (tdb_hnd_object *)self;
        int result, timeout = 30;
        char *s;

        if (!obj->tdb) {
                PyErr_SetString(py_tdb_error, "tdb object has been closed"); 
                return NULL;
        }       

        if (!PyArg_ParseTuple(args, "s|i", &s, &timeout))
                return NULL;

        result = tdb_lock_bystring_with_timeout(obj->tdb, s, timeout);

        return PyInt_FromLong(result != -1);
}

PyObject *py_tdb_hnd_unlock_bystring(PyObject *self, PyObject *args)
{
        tdb_hnd_object *obj = (tdb_hnd_object *)self;
        char *s;

        if (!obj->tdb) {
                PyErr_SetString(py_tdb_error, "tdb object has been closed"); 
                return NULL;
        }       

        if (!PyArg_ParseTuple(args, "s", &s))
                return NULL;

        tdb_unlock_bystring(obj->tdb, s);

        Py_INCREF(Py_None);
        return Py_None;
}

/* 
 * Method dispatch table for this module
 */

static PyMethodDef tdb_methods[] = {
        { "open", (PyCFunction)py_tdb_open, METH_VARARGS | METH_KEYWORDS },
        { "close", (PyCFunction)py_tdb_close, METH_VARARGS },
        { NULL }
};

/* 
 * Methods on a tdb object
 */

static PyMethodDef tdb_hnd_methods[] = {
        { "keys", (PyCFunction)py_tdb_hnd_keys, METH_VARARGS },
        { "has_key", (PyCFunction)py_tdb_hnd_has_key, METH_VARARGS },
        { "first_key", (PyCFunction)py_tdb_hnd_first_key, METH_VARARGS },
        { "next_key", (PyCFunction)py_tdb_hnd_next_key, METH_VARARGS },
        { "lock_all", (PyCFunction)py_tdb_hnd_lock_all, METH_VARARGS },
        { "unlock_all", (PyCFunction)py_tdb_hnd_unlock_all, METH_VARARGS },
        { "traverse", (PyCFunction)py_tdb_hnd_traverse, METH_VARARGS | METH_KEYWORDS },
        { "chainlock", (PyCFunction)py_tdb_hnd_chainlock, METH_VARARGS | METH_KEYWORDS },
        { "chainunlock", (PyCFunction)py_tdb_hnd_chainunlock, METH_VARARGS | METH_KEYWORDS },
        { "lock_bystring", (PyCFunction)py_tdb_hnd_lock_bystring, METH_VARARGS | METH_KEYWORDS },
        { "unlock_bystring", (PyCFunction)py_tdb_hnd_unlock_bystring, METH_VARARGS | METH_KEYWORDS },
        { NULL }
};

/* Deallocate a tdb handle object */

static void tdb_hnd_dealloc(PyObject* self)
{
        tdb_hnd_object *hnd = (tdb_hnd_object *)self;

        if (hnd->tdb) {
                tdb_close(hnd->tdb);
                hnd->tdb = NULL;
        }
}

/* Return tdb handle attributes */

static PyObject *tdb_hnd_getattr(PyObject *self, char *attrname)
{
        return Py_FindMethod(tdb_hnd_methods, self, attrname);
}

static char tdb_hnd_type_doc[] = 
"Python wrapper for tdb.";

PyTypeObject tdb_hnd_type = {
        PyObject_HEAD_INIT(NULL)
        0,
        "tdb",
        sizeof(tdb_hnd_object),
        0,
        tdb_hnd_dealloc,        /* tp_dealloc*/
        0,                      /* tp_print*/
        tdb_hnd_getattr,        /* tp_getattr*/
        0,                      /* tp_setattr*/
        0,                      /* tp_compare*/
        0,                      /* tp_repr*/
        0,                      /* tp_as_number*/
        0,                      /* tp_as_sequence*/
        &tdb_mapping,           /* tp_as_mapping*/
        0,                      /* tp_hash */
        0,                      /* tp_call */
        0,                      /* tp_str */
        0,                      /* tp_getattro */
        0,                      /* tp_setattro */
        0,                      /* tp_as_buffer*/
        Py_TPFLAGS_DEFAULT,     /* tp_flags */
        tdb_hnd_type_doc,       /* tp_doc */
};

/* Constants */

static struct const_vals {
        char *name;
        uint32 value;
} module_const_vals[] = {

        /* Flags for tdb_open() */

        { "TDB_DEFAULT", TDB_DEFAULT },
        { "TDB_CLEAR_IF_FIRST", TDB_CLEAR_IF_FIRST },
        { "TDB_INTERNAL", TDB_INTERNAL },
        { "TDB_NOLOCK", TDB_NOLOCK },
        { "TDB_NOMMAP", TDB_NOMMAP },
        { "TDB_CONVERT", TDB_CONVERT },
        { "TDB_BIGENDIAN", TDB_BIGENDIAN },
        
        { NULL },
};

static void const_init(PyObject *dict)
{
        struct const_vals *tmp;
        PyObject *obj;

        for (tmp = module_const_vals; tmp->name; tmp++) {
                obj = PyInt_FromLong(tmp->value);
                PyDict_SetItemString(dict, tmp->name, obj);
                Py_DECREF(obj);
        }
}

/* Module initialisation */

void inittdb(void)
{
        PyObject *module, *dict;

        /* Initialise module */

        module = Py_InitModule("tdb", tdb_methods);
        dict = PyModule_GetDict(module);

        py_tdb_error = PyErr_NewException("tdb.error", NULL, NULL);
        PyDict_SetItemString(dict, "error", py_tdb_error);

        /* Initialise policy handle object */

        tdb_hnd_type.ob_type = &PyType_Type;

        PyDict_SetItemString(dict, "tdb.hnd", 
                             (PyObject *)&tdb_hnd_type);

        /* Initialise constants */

        const_init(dict);
}

---