1
2/* DBM module using dictionary interface */
3
4
5#define PY_SSIZE_T_CLEAN
6#include "Python.h"
7
8#include <sys/types.h>
9#include <sys/stat.h>
10#include <fcntl.h>
11
12/* Some Linux systems install gdbm/ndbm.h, but not ndbm.h.  This supports
13 * whichever configure was able to locate.
14 */
15#if defined(HAVE_NDBM_H)
16#include <ndbm.h>
17static const char which_dbm[] = "GNU gdbm";  /* EMX port of GDBM */
18#elif defined(HAVE_GDBM_NDBM_H)
19#include <gdbm/ndbm.h>
20static const char which_dbm[] = "GNU gdbm";
21#elif defined(HAVE_GDBM_DASH_NDBM_H)
22#include <gdbm-ndbm.h>
23static const char which_dbm[] = "GNU gdbm";
24#elif defined(HAVE_BERKDB_H)
25#include <db.h>
26static const char which_dbm[] = "Berkeley DB";
27#else
28#error "No ndbm.h available!"
29#endif
30
31/*[clinic input]
32module _dbm
33class _dbm.dbm "dbmobject *" "&Dbmtype"
34[clinic start generated code]*/
35/*[clinic end generated code: output=da39a3ee5e6b4b0d input=9b1aa8756d16150e]*/
36
37typedef struct {
38    PyObject_HEAD
39    int di_size;        /* -1 means recompute */
40    DBM *di_dbm;
41} dbmobject;
42
43#include "clinic/_dbmmodule.c.h"
44
45static PyTypeObject Dbmtype;
46
47#define is_dbmobject(v) (Py_TYPE(v) == &Dbmtype)
48#define check_dbmobject_open(v) if ((v)->di_dbm == NULL) \
49               { PyErr_SetString(DbmError, "DBM object has already been closed"); \
50                 return NULL; }
51
52static PyObject *DbmError;
53
54static PyObject *
55newdbmobject(const char *file, int flags, int mode)
56{
57    dbmobject *dp;
58
59    dp = PyObject_New(dbmobject, &Dbmtype);
60    if (dp == NULL)
61        return NULL;
62    dp->di_size = -1;
63    /* See issue #19296 */
64    if ( (dp->di_dbm = dbm_open((char *)file, flags, mode)) == 0 ) {
65        PyErr_SetFromErrno(DbmError);
66        Py_DECREF(dp);
67        return NULL;
68    }
69    return (PyObject *)dp;
70}
71
72/* Methods */
73
74static void
75dbm_dealloc(dbmobject *dp)
76{
77    if ( dp->di_dbm )
78        dbm_close(dp->di_dbm);
79    PyObject_Del(dp);
80}
81
82static Py_ssize_t
83dbm_length(dbmobject *dp)
84{
85    if (dp->di_dbm == NULL) {
86             PyErr_SetString(DbmError, "DBM object has already been closed");
87             return -1;
88    }
89    if ( dp->di_size < 0 ) {
90        datum key;
91        int size;
92
93        size = 0;
94        for ( key=dbm_firstkey(dp->di_dbm); key.dptr;
95              key = dbm_nextkey(dp->di_dbm))
96            size++;
97        dp->di_size = size;
98    }
99    return dp->di_size;
100}
101
102static PyObject *
103dbm_subscript(dbmobject *dp, PyObject *key)
104{
105    datum drec, krec;
106    Py_ssize_t tmp_size;
107
108    if (!PyArg_Parse(key, "s#", &krec.dptr, &tmp_size) )
109        return NULL;
110
111    krec.dsize = tmp_size;
112    check_dbmobject_open(dp);
113    drec = dbm_fetch(dp->di_dbm, krec);
114    if ( drec.dptr == 0 ) {
115        PyErr_SetObject(PyExc_KeyError, key);
116        return NULL;
117    }
118    if ( dbm_error(dp->di_dbm) ) {
119        dbm_clearerr(dp->di_dbm);
120        PyErr_SetString(DbmError, "");
121        return NULL;
122    }
123    return PyBytes_FromStringAndSize(drec.dptr, drec.dsize);
124}
125
126static int
127dbm_ass_sub(dbmobject *dp, PyObject *v, PyObject *w)
128{
129    datum krec, drec;
130    Py_ssize_t tmp_size;
131
132    if ( !PyArg_Parse(v, "s#", &krec.dptr, &tmp_size) ) {
133        PyErr_SetString(PyExc_TypeError,
134                        "dbm mappings have bytes or string keys only");
135        return -1;
136    }
137    krec.dsize = tmp_size;
138    if (dp->di_dbm == NULL) {
139             PyErr_SetString(DbmError, "DBM object has already been closed");
140             return -1;
141    }
142    dp->di_size = -1;
143    if (w == NULL) {
144        if ( dbm_delete(dp->di_dbm, krec) < 0 ) {
145            dbm_clearerr(dp->di_dbm);
146            PyErr_SetObject(PyExc_KeyError, v);
147            return -1;
148        }
149    } else {
150        if ( !PyArg_Parse(w, "s#", &drec.dptr, &tmp_size) ) {
151            PyErr_SetString(PyExc_TypeError,
152                 "dbm mappings have byte or string elements only");
153            return -1;
154        }
155        drec.dsize = tmp_size;
156        if ( dbm_store(dp->di_dbm, krec, drec, DBM_REPLACE) < 0 ) {
157            dbm_clearerr(dp->di_dbm);
158            PyErr_SetString(DbmError,
159                            "cannot add item to database");
160            return -1;
161        }
162    }
163    if ( dbm_error(dp->di_dbm) ) {
164        dbm_clearerr(dp->di_dbm);
165        PyErr_SetString(DbmError, "");
166        return -1;
167    }
168    return 0;
169}
170
171static PyMappingMethods dbm_as_mapping = {
172    (lenfunc)dbm_length,                /*mp_length*/
173    (binaryfunc)dbm_subscript,          /*mp_subscript*/
174    (objobjargproc)dbm_ass_sub,         /*mp_ass_subscript*/
175};
176
177/*[clinic input]
178_dbm.dbm.close
179
180Close the database.
181[clinic start generated code]*/
182
183static PyObject *
184_dbm_dbm_close_impl(dbmobject *self)
185/*[clinic end generated code: output=c8dc5b6709600b86 input=046db72377d51be8]*/
186{
187    if (self->di_dbm)
188        dbm_close(self->di_dbm);
189    self->di_dbm = NULL;
190    Py_INCREF(Py_None);
191    return Py_None;
192}
193
194/*[clinic input]
195_dbm.dbm.keys
196
197Return a list of all keys in the database.
198[clinic start generated code]*/
199
200static PyObject *
201_dbm_dbm_keys_impl(dbmobject *self)
202/*[clinic end generated code: output=434549f7c121b33c input=d210ba778cd9c68a]*/
203{
204    PyObject *v, *item;
205    datum key;
206    int err;
207
208    check_dbmobject_open(self);
209    v = PyList_New(0);
210    if (v == NULL)
211        return NULL;
212    for (key = dbm_firstkey(self->di_dbm); key.dptr;
213         key = dbm_nextkey(self->di_dbm)) {
214        item = PyBytes_FromStringAndSize(key.dptr, key.dsize);
215        if (item == NULL) {
216            Py_DECREF(v);
217            return NULL;
218        }
219        err = PyList_Append(v, item);
220        Py_DECREF(item);
221        if (err != 0) {
222            Py_DECREF(v);
223            return NULL;
224        }
225    }
226    return v;
227}
228
229static int
230dbm_contains(PyObject *self, PyObject *arg)
231{
232    dbmobject *dp = (dbmobject *)self;
233    datum key, val;
234    Py_ssize_t size;
235
236    if ((dp)->di_dbm == NULL) {
237        PyErr_SetString(DbmError,
238                        "DBM object has already been closed");
239         return -1;
240    }
241    if (PyUnicode_Check(arg)) {
242        key.dptr = PyUnicode_AsUTF8AndSize(arg, &size);
243        key.dsize = size;
244        if (key.dptr == NULL)
245            return -1;
246    }
247    else if (!PyBytes_Check(arg)) {
248        PyErr_Format(PyExc_TypeError,
249                     "dbm key must be bytes or string, not %.100s",
250                     arg->ob_type->tp_name);
251        return -1;
252    }
253    else {
254        key.dptr = PyBytes_AS_STRING(arg);
255        key.dsize = PyBytes_GET_SIZE(arg);
256    }
257    val = dbm_fetch(dp->di_dbm, key);
258    return val.dptr != NULL;
259}
260
261static PySequenceMethods dbm_as_sequence = {
262    0,                          /* sq_length */
263    0,                          /* sq_concat */
264    0,                          /* sq_repeat */
265    0,                          /* sq_item */
266    0,                          /* sq_slice */
267    0,                          /* sq_ass_item */
268    0,                          /* sq_ass_slice */
269    dbm_contains,               /* sq_contains */
270    0,                          /* sq_inplace_concat */
271    0,                          /* sq_inplace_repeat */
272};
273
274/*[clinic input]
275_dbm.dbm.get
276
277    key: str(accept={str, robuffer}, zeroes=True)
278    default: object(c_default="NULL") = b''
279    /
280
281Return the value for key if present, otherwise default.
282[clinic start generated code]*/
283
284static PyObject *
285_dbm_dbm_get_impl(dbmobject *self, const char *key,
286                  Py_ssize_clean_t key_length, PyObject *default_value)
287/*[clinic end generated code: output=b44f95eba8203d93 input=a3a279957f85eb6d]*/
288/*[clinic end generated code: output=4f5c0e523eaf1251 input=9402c0af8582dc69]*/
289{
290    datum dbm_key, val;
291
292    dbm_key.dptr = (char *)key;
293    dbm_key.dsize = key_length;
294    check_dbmobject_open(self);
295    val = dbm_fetch(self->di_dbm, dbm_key);
296    if (val.dptr != NULL)
297        return PyBytes_FromStringAndSize(val.dptr, val.dsize);
298
299    Py_INCREF(default_value);
300    return default_value;
301}
302
303/*[clinic input]
304_dbm.dbm.setdefault
305    key: str(accept={str, robuffer}, zeroes=True)
306    default: object(c_default="NULL") = b''
307    /
308
309Return the value for key if present, otherwise default.
310
311If key is not in the database, it is inserted with default as the value.
312[clinic start generated code]*/
313
314static PyObject *
315_dbm_dbm_setdefault_impl(dbmobject *self, const char *key,
316                         Py_ssize_clean_t key_length,
317                         PyObject *default_value)
318/*[clinic end generated code: output=52545886cf272161 input=bf40c48edaca01d6]*/
319{
320    datum dbm_key, val;
321    Py_ssize_t tmp_size;
322
323    dbm_key.dptr = (char *)key;
324    dbm_key.dsize = key_length;
325    check_dbmobject_open(self);
326    val = dbm_fetch(self->di_dbm, dbm_key);
327    if (val.dptr != NULL)
328        return PyBytes_FromStringAndSize(val.dptr, val.dsize);
329    if (default_value == NULL) {
330        default_value = PyBytes_FromStringAndSize(NULL, 0);
331        if (default_value == NULL)
332            return NULL;
333        val.dptr = NULL;
334        val.dsize = 0;
335    }
336    else {
337        if ( !PyArg_Parse(default_value, "s#", &val.dptr, &tmp_size) ) {
338            PyErr_SetString(PyExc_TypeError,
339                "dbm mappings have byte string elements only");
340            return NULL;
341        }
342        val.dsize = tmp_size;
343        Py_INCREF(default_value);
344    }
345    if (dbm_store(self->di_dbm, dbm_key, val, DBM_INSERT) < 0) {
346        dbm_clearerr(self->di_dbm);
347        PyErr_SetString(DbmError, "cannot add item to database");
348        Py_DECREF(default_value);
349        return NULL;
350    }
351    return default_value;
352}
353
354static PyObject *
355dbm__enter__(PyObject *self, PyObject *args)
356{
357    Py_INCREF(self);
358    return self;
359}
360
361static PyObject *
362dbm__exit__(PyObject *self, PyObject *args)
363{
364    _Py_IDENTIFIER(close);
365    return _PyObject_CallMethodId(self, &PyId_close, NULL);
366}
367
368
369static PyMethodDef dbm_methods[] = {
370    _DBM_DBM_CLOSE_METHODDEF
371    _DBM_DBM_KEYS_METHODDEF
372    _DBM_DBM_GET_METHODDEF
373    _DBM_DBM_SETDEFAULT_METHODDEF
374    {"__enter__", dbm__enter__, METH_NOARGS, NULL},
375    {"__exit__",  dbm__exit__, METH_VARARGS, NULL},
376    {NULL,              NULL}           /* sentinel */
377};
378
379static PyTypeObject Dbmtype = {
380    PyVarObject_HEAD_INIT(NULL, 0)
381    "_dbm.dbm",
382    sizeof(dbmobject),
383    0,
384    (destructor)dbm_dealloc,  /*tp_dealloc*/
385    0,                            /*tp_print*/
386    0,                        /*tp_getattr*/
387    0,                            /*tp_setattr*/
388    0,                            /*tp_reserved*/
389    0,                            /*tp_repr*/
390    0,                            /*tp_as_number*/
391    &dbm_as_sequence,             /*tp_as_sequence*/
392    &dbm_as_mapping,              /*tp_as_mapping*/
393    0,                    /*tp_hash*/
394    0,                    /*tp_call*/
395    0,                    /*tp_str*/
396    0,                    /*tp_getattro*/
397    0,                    /*tp_setattro*/
398    0,                    /*tp_as_buffer*/
399    Py_TPFLAGS_DEFAULT,   /*tp_flags*/
400    0,                        /*tp_doc*/
401    0,                        /*tp_traverse*/
402    0,                        /*tp_clear*/
403    0,                        /*tp_richcompare*/
404    0,                        /*tp_weaklistoffset*/
405    0,                        /*tp_iter*/
406    0,                        /*tp_iternext*/
407    dbm_methods,          /*tp_methods*/
408};
409
410/* ----------------------------------------------------------------- */
411
412/*[clinic input]
413
414_dbm.open as dbmopen
415
416    filename: str
417        The filename to open.
418
419    flags: str="r"
420        How to open the file.  "r" for reading, "w" for writing, etc.
421
422    mode: int(py_default="0o666") = 0o666
423        If creating a new file, the mode bits for the new file
424        (e.g. os.O_RDWR).
425
426    /
427
428Return a database object.
429
430[clinic start generated code]*/
431
432static PyObject *
433dbmopen_impl(PyObject *module, const char *filename, const char *flags,
434             int mode)
435/*[clinic end generated code: output=5fade8cf16e0755f input=226334bade5764e6]*/
436{
437    int iflags;
438
439    if ( strcmp(flags, "r") == 0 )
440        iflags = O_RDONLY;
441    else if ( strcmp(flags, "w") == 0 )
442        iflags = O_RDWR;
443    else if ( strcmp(flags, "rw") == 0 ) /* B/W compat */
444        iflags = O_RDWR|O_CREAT;
445    else if ( strcmp(flags, "c") == 0 )
446        iflags = O_RDWR|O_CREAT;
447    else if ( strcmp(flags, "n") == 0 )
448        iflags = O_RDWR|O_CREAT|O_TRUNC;
449    else {
450        PyErr_SetString(DbmError,
451                        "arg 2 to open should be 'r', 'w', 'c', or 'n'");
452        return NULL;
453    }
454    return newdbmobject(filename, iflags, mode);
455}
456
457static PyMethodDef dbmmodule_methods[] = {
458    DBMOPEN_METHODDEF
459    { 0, 0 },
460};
461
462
463static struct PyModuleDef _dbmmodule = {
464    PyModuleDef_HEAD_INIT,
465    "_dbm",
466    NULL,
467    -1,
468    dbmmodule_methods,
469    NULL,
470    NULL,
471    NULL,
472    NULL
473};
474
475PyMODINIT_FUNC
476PyInit__dbm(void) {
477    PyObject *m, *d, *s;
478
479    if (PyType_Ready(&Dbmtype) < 0)
480        return NULL;
481    m = PyModule_Create(&_dbmmodule);
482    if (m == NULL)
483        return NULL;
484    d = PyModule_GetDict(m);
485    if (DbmError == NULL)
486        DbmError = PyErr_NewException("_dbm.error",
487                                      PyExc_IOError, NULL);
488    s = PyUnicode_FromString(which_dbm);
489    if (s != NULL) {
490        PyDict_SetItemString(d, "library", s);
491        Py_DECREF(s);
492    }
493    if (DbmError != NULL)
494        PyDict_SetItemString(d, "error", DbmError);
495    if (PyErr_Occurred()) {
496        Py_DECREF(m);
497        m = NULL;
498    }
499    return m;
500}
501