1 /*
2 * interface to SPI functions
3 *
4 * src/pl/plpython/plpy_spi.c
5 */
6
7 #include "postgres.h"
8
9 #include <limits.h>
10
11 #include "access/htup_details.h"
12 #include "access/xact.h"
13 #include "catalog/pg_type.h"
14 #include "executor/spi.h"
15 #include "mb/pg_wchar.h"
16 #include "parser/parse_type.h"
17 #include "utils/memutils.h"
18 #include "utils/syscache.h"
19
20 #include "plpython.h"
21
22 #include "plpy_spi.h"
23
24 #include "plpy_elog.h"
25 #include "plpy_main.h"
26 #include "plpy_planobject.h"
27 #include "plpy_plpymodule.h"
28 #include "plpy_procedure.h"
29 #include "plpy_resultobject.h"
30
31
32 static PyObject *PLy_spi_execute_query(char *query, long limit);
33 static PyObject *PLy_spi_execute_fetch_result(SPITupleTable *tuptable,
34 uint64 rows, int status);
35 static void PLy_spi_exception_set(PyObject *excclass, ErrorData *edata);
36
37
38 /* prepare(query="select * from foo")
39 * prepare(query="select * from foo where bar = $1", params=["text"])
40 * prepare(query="select * from foo where bar = $1", params=["text"], limit=5)
41 */
42 PyObject *
PLy_spi_prepare(PyObject * self,PyObject * args)43 PLy_spi_prepare(PyObject *self, PyObject *args)
44 {
45 PLyPlanObject *plan;
46 PyObject *list = NULL;
47 PyObject *volatile optr = NULL;
48 char *query;
49 volatile MemoryContext oldcontext;
50 volatile ResourceOwner oldowner;
51 volatile int nargs;
52
53 if (!PyArg_ParseTuple(args, "s|O:prepare", &query, &list))
54 return NULL;
55
56 if (list && (!PySequence_Check(list)))
57 {
58 PLy_exception_set(PyExc_TypeError,
59 "second argument of plpy.prepare must be a sequence");
60 return NULL;
61 }
62
63 if ((plan = (PLyPlanObject *) PLy_plan_new()) == NULL)
64 return NULL;
65
66 plan->mcxt = AllocSetContextCreate(TopMemoryContext,
67 "PL/Python plan context",
68 ALLOCSET_DEFAULT_SIZES);
69 oldcontext = MemoryContextSwitchTo(plan->mcxt);
70
71 nargs = list ? PySequence_Length(list) : 0;
72
73 plan->nargs = nargs;
74 plan->types = nargs ? palloc(sizeof(Oid) * nargs) : NULL;
75 plan->values = nargs ? palloc(sizeof(Datum) * nargs) : NULL;
76 plan->args = nargs ? palloc(sizeof(PLyTypeInfo) * nargs) : NULL;
77
78 MemoryContextSwitchTo(oldcontext);
79
80 oldcontext = CurrentMemoryContext;
81 oldowner = CurrentResourceOwner;
82
83 PLy_spi_subtransaction_begin(oldcontext, oldowner);
84
85 PG_TRY();
86 {
87 int i;
88 PLyExecutionContext *exec_ctx = PLy_current_execution_context();
89
90 /*
91 * the other loop might throw an exception, if PLyTypeInfo member
92 * isn't properly initialized the Py_DECREF(plan) will go boom
93 */
94 for (i = 0; i < nargs; i++)
95 {
96 PLy_typeinfo_init(&plan->args[i], plan->mcxt);
97 plan->values[i] = PointerGetDatum(NULL);
98 }
99
100 for (i = 0; i < nargs; i++)
101 {
102 char *sptr;
103 HeapTuple typeTup;
104 Oid typeId;
105 int32 typmod;
106
107 optr = PySequence_GetItem(list, i);
108 if (PyString_Check(optr))
109 sptr = PyString_AsString(optr);
110 else if (PyUnicode_Check(optr))
111 sptr = PLyUnicode_AsString(optr);
112 else
113 {
114 ereport(ERROR,
115 (errmsg("plpy.prepare: type name at ordinal position %d is not a string", i)));
116 sptr = NULL; /* keep compiler quiet */
117 }
118
119 /********************************************************
120 * Resolve argument type names and then look them up by
121 * oid in the system cache, and remember the required
122 *information for input conversion.
123 ********************************************************/
124
125 parseTypeString(sptr, &typeId, &typmod, false);
126
127 typeTup = SearchSysCache1(TYPEOID,
128 ObjectIdGetDatum(typeId));
129 if (!HeapTupleIsValid(typeTup))
130 elog(ERROR, "cache lookup failed for type %u", typeId);
131
132 Py_DECREF(optr);
133
134 /*
135 * set optr to NULL, so we won't try to unref it again in case of
136 * an error
137 */
138 optr = NULL;
139
140 plan->types[i] = typeId;
141 PLy_output_datum_func(&plan->args[i], typeTup, exec_ctx->curr_proc->langid, exec_ctx->curr_proc->trftypes);
142 ReleaseSysCache(typeTup);
143 }
144
145 pg_verifymbstr(query, strlen(query), false);
146 plan->plan = SPI_prepare(query, plan->nargs, plan->types);
147 if (plan->plan == NULL)
148 elog(ERROR, "SPI_prepare failed: %s",
149 SPI_result_code_string(SPI_result));
150
151 /* transfer plan from procCxt to topCxt */
152 if (SPI_keepplan(plan->plan))
153 elog(ERROR, "SPI_keepplan failed");
154
155 PLy_spi_subtransaction_commit(oldcontext, oldowner);
156 }
157 PG_CATCH();
158 {
159 Py_DECREF(plan);
160 Py_XDECREF(optr);
161
162 PLy_spi_subtransaction_abort(oldcontext, oldowner);
163 return NULL;
164 }
165 PG_END_TRY();
166
167 Assert(plan->plan != NULL);
168 return (PyObject *) plan;
169 }
170
171 /* execute(query="select * from foo", limit=5)
172 * execute(plan=plan, values=(foo, bar), limit=5)
173 */
174 PyObject *
PLy_spi_execute(PyObject * self,PyObject * args)175 PLy_spi_execute(PyObject *self, PyObject *args)
176 {
177 char *query;
178 PyObject *plan;
179 PyObject *list = NULL;
180 long limit = 0;
181
182 if (PyArg_ParseTuple(args, "s|l", &query, &limit))
183 return PLy_spi_execute_query(query, limit);
184
185 PyErr_Clear();
186
187 if (PyArg_ParseTuple(args, "O|Ol", &plan, &list, &limit) &&
188 is_PLyPlanObject(plan))
189 return PLy_spi_execute_plan(plan, list, limit);
190
191 PLy_exception_set(PLy_exc_error, "plpy.execute expected a query or a plan");
192 return NULL;
193 }
194
195 PyObject *
PLy_spi_execute_plan(PyObject * ob,PyObject * list,long limit)196 PLy_spi_execute_plan(PyObject *ob, PyObject *list, long limit)
197 {
198 volatile int nargs;
199 int i,
200 rv;
201 PLyPlanObject *plan;
202 volatile MemoryContext oldcontext;
203 volatile ResourceOwner oldowner;
204 PyObject *ret;
205
206 if (list != NULL)
207 {
208 if (!PySequence_Check(list) || PyString_Check(list) || PyUnicode_Check(list))
209 {
210 PLy_exception_set(PyExc_TypeError, "plpy.execute takes a sequence as its second argument");
211 return NULL;
212 }
213 nargs = PySequence_Length(list);
214 }
215 else
216 nargs = 0;
217
218 plan = (PLyPlanObject *) ob;
219
220 if (nargs != plan->nargs)
221 {
222 char *sv;
223 PyObject *so = PyObject_Str(list);
224
225 if (!so)
226 PLy_elog(ERROR, "could not execute plan");
227 sv = PyString_AsString(so);
228 PLy_exception_set_plural(PyExc_TypeError,
229 "Expected sequence of %d argument, got %d: %s",
230 "Expected sequence of %d arguments, got %d: %s",
231 plan->nargs,
232 plan->nargs, nargs, sv);
233 Py_DECREF(so);
234
235 return NULL;
236 }
237
238 oldcontext = CurrentMemoryContext;
239 oldowner = CurrentResourceOwner;
240
241 PLy_spi_subtransaction_begin(oldcontext, oldowner);
242
243 PG_TRY();
244 {
245 PLyExecutionContext *exec_ctx = PLy_current_execution_context();
246 char *volatile nulls;
247 volatile int j;
248
249 if (nargs > 0)
250 nulls = palloc(nargs * sizeof(char));
251 else
252 nulls = NULL;
253
254 for (j = 0; j < nargs; j++)
255 {
256 PyObject *elem;
257
258 elem = PySequence_GetItem(list, j);
259 if (elem != Py_None)
260 {
261 PG_TRY();
262 {
263 plan->values[j] =
264 plan->args[j].out.d.func(&(plan->args[j].out.d),
265 -1,
266 elem,
267 false);
268 }
269 PG_CATCH();
270 {
271 Py_DECREF(elem);
272 PG_RE_THROW();
273 }
274 PG_END_TRY();
275
276 Py_DECREF(elem);
277 nulls[j] = ' ';
278 }
279 else
280 {
281 Py_DECREF(elem);
282 plan->values[j] =
283 InputFunctionCall(&(plan->args[j].out.d.typfunc),
284 NULL,
285 plan->args[j].out.d.typioparam,
286 -1);
287 nulls[j] = 'n';
288 }
289 }
290
291 rv = SPI_execute_plan(plan->plan, plan->values, nulls,
292 exec_ctx->curr_proc->fn_readonly, limit);
293 ret = PLy_spi_execute_fetch_result(SPI_tuptable, SPI_processed, rv);
294
295 if (nargs > 0)
296 pfree(nulls);
297
298 PLy_spi_subtransaction_commit(oldcontext, oldowner);
299 }
300 PG_CATCH();
301 {
302 int k;
303
304 /*
305 * cleanup plan->values array
306 */
307 for (k = 0; k < nargs; k++)
308 {
309 if (!plan->args[k].out.d.typbyval &&
310 (plan->values[k] != PointerGetDatum(NULL)))
311 {
312 pfree(DatumGetPointer(plan->values[k]));
313 plan->values[k] = PointerGetDatum(NULL);
314 }
315 }
316
317 PLy_spi_subtransaction_abort(oldcontext, oldowner);
318 return NULL;
319 }
320 PG_END_TRY();
321
322 for (i = 0; i < nargs; i++)
323 {
324 if (!plan->args[i].out.d.typbyval &&
325 (plan->values[i] != PointerGetDatum(NULL)))
326 {
327 pfree(DatumGetPointer(plan->values[i]));
328 plan->values[i] = PointerGetDatum(NULL);
329 }
330 }
331
332 if (rv < 0)
333 {
334 PLy_exception_set(PLy_exc_spi_error,
335 "SPI_execute_plan failed: %s",
336 SPI_result_code_string(rv));
337 return NULL;
338 }
339
340 return ret;
341 }
342
343 static PyObject *
PLy_spi_execute_query(char * query,long limit)344 PLy_spi_execute_query(char *query, long limit)
345 {
346 int rv;
347 volatile MemoryContext oldcontext;
348 volatile ResourceOwner oldowner;
349 PyObject *ret = NULL;
350
351 oldcontext = CurrentMemoryContext;
352 oldowner = CurrentResourceOwner;
353
354 PLy_spi_subtransaction_begin(oldcontext, oldowner);
355
356 PG_TRY();
357 {
358 PLyExecutionContext *exec_ctx = PLy_current_execution_context();
359
360 pg_verifymbstr(query, strlen(query), false);
361 rv = SPI_execute(query, exec_ctx->curr_proc->fn_readonly, limit);
362 ret = PLy_spi_execute_fetch_result(SPI_tuptable, SPI_processed, rv);
363
364 PLy_spi_subtransaction_commit(oldcontext, oldowner);
365 }
366 PG_CATCH();
367 {
368 PLy_spi_subtransaction_abort(oldcontext, oldowner);
369 return NULL;
370 }
371 PG_END_TRY();
372
373 if (rv < 0)
374 {
375 Py_XDECREF(ret);
376 PLy_exception_set(PLy_exc_spi_error,
377 "SPI_execute failed: %s",
378 SPI_result_code_string(rv));
379 return NULL;
380 }
381
382 return ret;
383 }
384
385 static PyObject *
PLy_spi_execute_fetch_result(SPITupleTable * tuptable,uint64 rows,int status)386 PLy_spi_execute_fetch_result(SPITupleTable *tuptable, uint64 rows, int status)
387 {
388 PLyResultObject *result;
389 volatile MemoryContext oldcontext;
390
391 result = (PLyResultObject *) PLy_result_new();
392 Py_DECREF(result->status);
393 result->status = PyInt_FromLong(status);
394
395 if (status > 0 && tuptable == NULL)
396 {
397 Py_DECREF(result->nrows);
398 result->nrows = (rows > (uint64) LONG_MAX) ?
399 PyFloat_FromDouble((double) rows) :
400 PyInt_FromLong((long) rows);
401 }
402 else if (status > 0 && tuptable != NULL)
403 {
404 PLyTypeInfo args;
405 MemoryContext cxt;
406
407 Py_DECREF(result->nrows);
408 result->nrows = (rows > (uint64) LONG_MAX) ?
409 PyFloat_FromDouble((double) rows) :
410 PyInt_FromLong((long) rows);
411
412 cxt = AllocSetContextCreate(CurrentMemoryContext,
413 "PL/Python temp context",
414 ALLOCSET_DEFAULT_SIZES);
415 PLy_typeinfo_init(&args, cxt);
416
417 oldcontext = CurrentMemoryContext;
418 PG_TRY();
419 {
420 MemoryContext oldcontext2;
421
422 if (rows)
423 {
424 uint64 i;
425
426 /*
427 * PyList_New() and PyList_SetItem() use Py_ssize_t for list
428 * size and list indices; so we cannot support a result larger
429 * than PY_SSIZE_T_MAX.
430 */
431 if (rows > (uint64) PY_SSIZE_T_MAX)
432 ereport(ERROR,
433 (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
434 errmsg("query result has too many rows to fit in a Python list")));
435
436 Py_DECREF(result->rows);
437 result->rows = PyList_New(rows);
438
439 PLy_input_tuple_funcs(&args, tuptable->tupdesc);
440 for (i = 0; i < rows; i++)
441 {
442 PyObject *row = PLyDict_FromTuple(&args,
443 tuptable->vals[i],
444 tuptable->tupdesc);
445
446 PyList_SetItem(result->rows, i, row);
447 }
448 }
449
450 /*
451 * Save tuple descriptor for later use by result set metadata
452 * functions. Save it in TopMemoryContext so that it survives
453 * outside of an SPI context. We trust that PLy_result_dealloc()
454 * will clean it up when the time is right. (Do this as late as
455 * possible, to minimize the number of ways the tupdesc could get
456 * leaked due to errors.)
457 */
458 oldcontext2 = MemoryContextSwitchTo(TopMemoryContext);
459 result->tupdesc = CreateTupleDescCopy(tuptable->tupdesc);
460 MemoryContextSwitchTo(oldcontext2);
461 }
462 PG_CATCH();
463 {
464 MemoryContextSwitchTo(oldcontext);
465 MemoryContextDelete(cxt);
466 Py_DECREF(result);
467 PG_RE_THROW();
468 }
469 PG_END_TRY();
470
471 MemoryContextDelete(cxt);
472 SPI_freetuptable(tuptable);
473 }
474
475 return (PyObject *) result;
476 }
477
478 /*
479 * Utilities for running SPI functions in subtransactions.
480 *
481 * Usage:
482 *
483 * MemoryContext oldcontext = CurrentMemoryContext;
484 * ResourceOwner oldowner = CurrentResourceOwner;
485 *
486 * PLy_spi_subtransaction_begin(oldcontext, oldowner);
487 * PG_TRY();
488 * {
489 * <call SPI functions>
490 * PLy_spi_subtransaction_commit(oldcontext, oldowner);
491 * }
492 * PG_CATCH();
493 * {
494 * <do cleanup>
495 * PLy_spi_subtransaction_abort(oldcontext, oldowner);
496 * return NULL;
497 * }
498 * PG_END_TRY();
499 *
500 * These utilities take care of restoring connection to the SPI manager and
501 * setting a Python exception in case of an abort.
502 */
503 void
PLy_spi_subtransaction_begin(MemoryContext oldcontext,ResourceOwner oldowner)504 PLy_spi_subtransaction_begin(MemoryContext oldcontext, ResourceOwner oldowner)
505 {
506 BeginInternalSubTransaction(NULL);
507 /* Want to run inside function's memory context */
508 MemoryContextSwitchTo(oldcontext);
509 }
510
511 void
PLy_spi_subtransaction_commit(MemoryContext oldcontext,ResourceOwner oldowner)512 PLy_spi_subtransaction_commit(MemoryContext oldcontext, ResourceOwner oldowner)
513 {
514 /* Commit the inner transaction, return to outer xact context */
515 ReleaseCurrentSubTransaction();
516 MemoryContextSwitchTo(oldcontext);
517 CurrentResourceOwner = oldowner;
518 }
519
520 void
PLy_spi_subtransaction_abort(MemoryContext oldcontext,ResourceOwner oldowner)521 PLy_spi_subtransaction_abort(MemoryContext oldcontext, ResourceOwner oldowner)
522 {
523 ErrorData *edata;
524 PLyExceptionEntry *entry;
525 PyObject *exc;
526
527 /* Save error info */
528 MemoryContextSwitchTo(oldcontext);
529 edata = CopyErrorData();
530 FlushErrorState();
531
532 /* Abort the inner transaction */
533 RollbackAndReleaseCurrentSubTransaction();
534 MemoryContextSwitchTo(oldcontext);
535 CurrentResourceOwner = oldowner;
536
537 /* Look up the correct exception */
538 entry = hash_search(PLy_spi_exceptions, &(edata->sqlerrcode),
539 HASH_FIND, NULL);
540
541 /*
542 * This could be a custom error code, if that's the case fallback to
543 * SPIError
544 */
545 exc = entry ? entry->exc : PLy_exc_spi_error;
546 /* Make Python raise the exception */
547 PLy_spi_exception_set(exc, edata);
548 FreeErrorData(edata);
549 }
550
551 /*
552 * Raise a SPIError, passing in it more error details, like the
553 * internal query and error position.
554 */
555 static void
PLy_spi_exception_set(PyObject * excclass,ErrorData * edata)556 PLy_spi_exception_set(PyObject *excclass, ErrorData *edata)
557 {
558 PyObject *args = NULL;
559 PyObject *spierror = NULL;
560 PyObject *spidata = NULL;
561
562 args = Py_BuildValue("(s)", edata->message);
563 if (!args)
564 goto failure;
565
566 /* create a new SPI exception with the error message as the parameter */
567 spierror = PyObject_CallObject(excclass, args);
568 if (!spierror)
569 goto failure;
570
571 spidata = Py_BuildValue("(izzzizzzzz)", edata->sqlerrcode, edata->detail, edata->hint,
572 edata->internalquery, edata->internalpos,
573 edata->schema_name, edata->table_name, edata->column_name,
574 edata->datatype_name, edata->constraint_name);
575 if (!spidata)
576 goto failure;
577
578 if (PyObject_SetAttrString(spierror, "spidata", spidata) == -1)
579 goto failure;
580
581 PyErr_SetObject(excclass, spierror);
582
583 Py_DECREF(args);
584 Py_DECREF(spierror);
585 Py_DECREF(spidata);
586 return;
587
588 failure:
589 Py_XDECREF(args);
590 Py_XDECREF(spierror);
591 Py_XDECREF(spidata);
592 elog(ERROR, "could not convert SPI error to Python exception");
593 }
594