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plpy_exec.c
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1 /*
2  * executing Python code
3  *
4  * src/pl/plpython/plpy_exec.c
5  */
6 
7 #include "postgres.h"
8 
9 #include "access/htup_details.h"
10 #include "access/xact.h"
11 #include "catalog/pg_type.h"
12 #include "commands/trigger.h"
13 #include "executor/spi.h"
14 #include "funcapi.h"
15 #include "plpy_elog.h"
16 #include "plpy_exec.h"
17 #include "plpy_main.h"
18 #include "plpy_procedure.h"
19 #include "plpy_subxactobject.h"
20 #include "plpython.h"
21 #include "utils/builtins.h"
22 #include "utils/lsyscache.h"
23 #include "utils/rel.h"
24 #include "utils/typcache.h"
25 
26 /* saved state for a set-returning function */
27 typedef struct PLySRFState
28 {
29  PyObject *iter; /* Python iterator producing results */
30  PLySavedArgs *savedargs; /* function argument values */
31  MemoryContextCallback callback; /* for releasing refcounts when done */
33 
34 static PyObject *PLy_function_build_args(FunctionCallInfo fcinfo, PLyProcedure *proc);
36 static void PLy_function_restore_args(PLyProcedure *proc, PLySavedArgs *savedargs);
37 static void PLy_function_drop_args(PLySavedArgs *savedargs);
38 static void PLy_global_args_push(PLyProcedure *proc);
39 static void PLy_global_args_pop(PLyProcedure *proc);
40 static void plpython_srf_cleanup_callback(void *arg);
41 static void plpython_return_error_callback(void *arg);
42 
43 static PyObject *PLy_trigger_build_args(FunctionCallInfo fcinfo, PLyProcedure *proc,
44  HeapTuple *rv);
45 static HeapTuple PLy_modify_tuple(PLyProcedure *proc, PyObject *pltd,
46  TriggerData *tdata, HeapTuple otup);
47 static void plpython_trigger_error_callback(void *arg);
48 
49 static PyObject *PLy_procedure_call(PLyProcedure *proc, const char *kargs, PyObject *vargs);
50 static void PLy_abort_open_subtransactions(int save_subxact_level);
51 
52 
53 /* function subhandler */
54 Datum
56 {
57  bool is_setof = proc->is_setof;
58  Datum rv;
59  PyObject *volatile plargs = NULL;
60  PyObject *volatile plrv = NULL;
61  FuncCallContext *volatile funcctx = NULL;
62  PLySRFState *volatile srfstate = NULL;
63  ErrorContextCallback plerrcontext;
64 
65  /*
66  * If the function is called recursively, we must push outer-level
67  * arguments into the stack. This must be immediately before the PG_TRY
68  * to ensure that the corresponding pop happens.
69  */
71 
72  PG_TRY();
73  {
74  if (is_setof)
75  {
76  /* First Call setup */
77  if (SRF_IS_FIRSTCALL())
78  {
79  funcctx = SRF_FIRSTCALL_INIT();
80  srfstate = (PLySRFState *)
82  sizeof(PLySRFState));
83  /* Immediately register cleanup callback */
85  srfstate->callback.arg = (void *) srfstate;
87  &srfstate->callback);
88  funcctx->user_fctx = (void *) srfstate;
89  }
90  /* Every call setup */
91  funcctx = SRF_PERCALL_SETUP();
92  Assert(funcctx != NULL);
93  srfstate = (PLySRFState *) funcctx->user_fctx;
94  Assert(srfstate != NULL);
95  }
96 
97  if (srfstate == NULL || srfstate->iter == NULL)
98  {
99  /*
100  * Non-SETOF function or first time for SETOF function: build
101  * args, then actually execute the function.
102  */
103  plargs = PLy_function_build_args(fcinfo, proc);
104  plrv = PLy_procedure_call(proc, "args", plargs);
105  Assert(plrv != NULL);
106  }
107  else
108  {
109  /*
110  * Second or later call for a SETOF function: restore arguments in
111  * globals dict to what they were when we left off. We must do
112  * this in case multiple evaluations of the same SETOF function
113  * are interleaved. It's a bit annoying, since the iterator may
114  * not look at the arguments at all, but we have no way to know
115  * that. Fortunately this isn't terribly expensive.
116  */
117  if (srfstate->savedargs)
118  PLy_function_restore_args(proc, srfstate->savedargs);
119  srfstate->savedargs = NULL; /* deleted by restore_args */
120  }
121 
122  /*
123  * If it returns a set, call the iterator to get the next return item.
124  * We stay in the SPI context while doing this, because PyIter_Next()
125  * calls back into Python code which might contain SPI calls.
126  */
127  if (is_setof)
128  {
129  if (srfstate->iter == NULL)
130  {
131  /* first time -- do checks and setup */
132  ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
133 
134  if (!rsi || !IsA(rsi, ReturnSetInfo) ||
135  (rsi->allowedModes & SFRM_ValuePerCall) == 0)
136  {
137  ereport(ERROR,
138  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
139  errmsg("unsupported set function return mode"),
140  errdetail("PL/Python set-returning functions only support returning one value per call.")));
141  }
143 
144  /* Make iterator out of returned object */
145  srfstate->iter = PyObject_GetIter(plrv);
146 
147  Py_DECREF(plrv);
148  plrv = NULL;
149 
150  if (srfstate->iter == NULL)
151  ereport(ERROR,
152  (errcode(ERRCODE_DATATYPE_MISMATCH),
153  errmsg("returned object cannot be iterated"),
154  errdetail("PL/Python set-returning functions must return an iterable object.")));
155  }
156 
157  /* Fetch next from iterator */
158  plrv = PyIter_Next(srfstate->iter);
159  if (plrv == NULL)
160  {
161  /* Iterator is exhausted or error happened */
162  bool has_error = (PyErr_Occurred() != NULL);
163 
164  Py_DECREF(srfstate->iter);
165  srfstate->iter = NULL;
166 
167  if (has_error)
168  PLy_elog(ERROR, "error fetching next item from iterator");
169 
170  /* Pass a null through the data-returning steps below */
171  Py_INCREF(Py_None);
172  plrv = Py_None;
173  }
174  else
175  {
176  /*
177  * This won't be last call, so save argument values. We do
178  * this again each time in case the iterator is changing those
179  * values.
180  */
181  srfstate->savedargs = PLy_function_save_args(proc);
182  }
183  }
184 
185  /*
186  * Disconnect from SPI manager and then create the return values datum
187  * (if the input function does a palloc for it this must not be
188  * allocated in the SPI memory context because SPI_finish would free
189  * it).
190  */
191  if (SPI_finish() != SPI_OK_FINISH)
192  elog(ERROR, "SPI_finish failed");
193 
195  plerrcontext.previous = error_context_stack;
196  error_context_stack = &plerrcontext;
197 
198  /*
199  * For a procedure or function declared to return void, the Python
200  * return value must be None. For void-returning functions, we also
201  * treat a None return value as a special "void datum" rather than
202  * NULL (as is the case for non-void-returning functions).
203  */
204  if (proc->result.typoid == VOIDOID)
205  {
206  if (plrv != Py_None)
207  {
208  if (proc->is_procedure)
209  ereport(ERROR,
210  (errcode(ERRCODE_DATATYPE_MISMATCH),
211  errmsg("PL/Python procedure did not return None")));
212  else
213  ereport(ERROR,
214  (errcode(ERRCODE_DATATYPE_MISMATCH),
215  errmsg("PL/Python function with return type \"void\" did not return None")));
216  }
217 
218  fcinfo->isnull = false;
219  rv = (Datum) 0;
220  }
221  else if (plrv == Py_None &&
222  srfstate && srfstate->iter == NULL)
223  {
224  /*
225  * In a SETOF function, the iteration-ending null isn't a real
226  * value; don't pass it through the input function, which might
227  * complain.
228  */
229  fcinfo->isnull = true;
230  rv = (Datum) 0;
231  }
232  else
233  {
234  /* Normal conversion of result */
235  rv = PLy_output_convert(&proc->result, plrv,
236  &fcinfo->isnull);
237  }
238  }
239  PG_CATCH();
240  {
241  /* Pop old arguments from the stack if they were pushed above */
242  PLy_global_args_pop(proc);
243 
244  Py_XDECREF(plargs);
245  Py_XDECREF(plrv);
246 
247  /*
248  * If there was an error within a SRF, the iterator might not have
249  * been exhausted yet. Clear it so the next invocation of the
250  * function will start the iteration again. (This code is probably
251  * unnecessary now; plpython_srf_cleanup_callback should take care of
252  * cleanup. But it doesn't hurt anything to do it here.)
253  */
254  if (srfstate)
255  {
256  Py_XDECREF(srfstate->iter);
257  srfstate->iter = NULL;
258  /* And drop any saved args; we won't need them */
259  if (srfstate->savedargs)
261  srfstate->savedargs = NULL;
262  }
263 
264  PG_RE_THROW();
265  }
266  PG_END_TRY();
267 
268  error_context_stack = plerrcontext.previous;
269 
270  /* Pop old arguments from the stack if they were pushed above */
271  PLy_global_args_pop(proc);
272 
273  Py_XDECREF(plargs);
274  Py_DECREF(plrv);
275 
276  if (srfstate)
277  {
278  /* We're in a SRF, exit appropriately */
279  if (srfstate->iter == NULL)
280  {
281  /* Iterator exhausted, so we're done */
282  SRF_RETURN_DONE(funcctx);
283  }
284  else if (fcinfo->isnull)
285  SRF_RETURN_NEXT_NULL(funcctx);
286  else
287  SRF_RETURN_NEXT(funcctx, rv);
288  }
289 
290  /* Plain function, just return the Datum value (possibly null) */
291  return rv;
292 }
293 
294 /* trigger subhandler
295  *
296  * the python function is expected to return Py_None if the tuple is
297  * acceptable and unmodified. Otherwise it should return a PyUnicode
298  * object who's value is SKIP, or MODIFY. SKIP means don't perform
299  * this action. MODIFY means the tuple has been modified, so update
300  * tuple and perform action. SKIP and MODIFY assume the trigger fires
301  * BEFORE the event and is ROW level. postgres expects the function
302  * to take no arguments and return an argument of type trigger.
303  */
304 HeapTuple
306 {
307  HeapTuple rv = NULL;
308  PyObject *volatile plargs = NULL;
309  PyObject *volatile plrv = NULL;
310  TriggerData *tdata;
311  TupleDesc rel_descr;
312 
313  Assert(CALLED_AS_TRIGGER(fcinfo));
314  tdata = (TriggerData *) fcinfo->context;
315 
316  /*
317  * Input/output conversion for trigger tuples. We use the result and
318  * result_in fields to store the tuple conversion info. We do this over
319  * again on each call to cover the possibility that the relation's tupdesc
320  * changed since the trigger was last called. The PLy_xxx_setup_func
321  * calls should only happen once, but PLy_input_setup_tuple and
322  * PLy_output_setup_tuple are responsible for not doing repetitive work.
323  */
324  rel_descr = RelationGetDescr(tdata->tg_relation);
325  if (proc->result.typoid != rel_descr->tdtypeid)
326  PLy_output_setup_func(&proc->result, proc->mcxt,
327  rel_descr->tdtypeid,
328  rel_descr->tdtypmod,
329  proc);
330  if (proc->result_in.typoid != rel_descr->tdtypeid)
331  PLy_input_setup_func(&proc->result_in, proc->mcxt,
332  rel_descr->tdtypeid,
333  rel_descr->tdtypmod,
334  proc);
335  PLy_output_setup_tuple(&proc->result, rel_descr, proc);
336  PLy_input_setup_tuple(&proc->result_in, rel_descr, proc);
337 
338  PG_TRY();
339  {
341 
342  rc = SPI_register_trigger_data(tdata);
343  Assert(rc >= 0);
344 
345  plargs = PLy_trigger_build_args(fcinfo, proc, &rv);
346  plrv = PLy_procedure_call(proc, "TD", plargs);
347 
348  Assert(plrv != NULL);
349 
350  /*
351  * Disconnect from SPI manager
352  */
353  if (SPI_finish() != SPI_OK_FINISH)
354  elog(ERROR, "SPI_finish failed");
355 
356  /*
357  * return of None means we're happy with the tuple
358  */
359  if (plrv != Py_None)
360  {
361  char *srv;
362 
363  if (PyUnicode_Check(plrv))
364  srv = PLyUnicode_AsString(plrv);
365  else
366  {
367  ereport(ERROR,
368  (errcode(ERRCODE_DATA_EXCEPTION),
369  errmsg("unexpected return value from trigger procedure"),
370  errdetail("Expected None or a string.")));
371  srv = NULL; /* keep compiler quiet */
372  }
373 
374  if (pg_strcasecmp(srv, "SKIP") == 0)
375  rv = NULL;
376  else if (pg_strcasecmp(srv, "MODIFY") == 0)
377  {
378  if (TRIGGER_FIRED_BY_INSERT(tdata->tg_event) ||
380  rv = PLy_modify_tuple(proc, plargs, tdata, rv);
381  else
383  (errmsg("PL/Python trigger function returned \"MODIFY\" in a DELETE trigger -- ignored")));
384  }
385  else if (pg_strcasecmp(srv, "OK") != 0)
386  {
387  /*
388  * accept "OK" as an alternative to None; otherwise, raise an
389  * error
390  */
391  ereport(ERROR,
392  (errcode(ERRCODE_DATA_EXCEPTION),
393  errmsg("unexpected return value from trigger procedure"),
394  errdetail("Expected None, \"OK\", \"SKIP\", or \"MODIFY\".")));
395  }
396  }
397  }
398  PG_FINALLY();
399  {
400  Py_XDECREF(plargs);
401  Py_XDECREF(plrv);
402  }
403  PG_END_TRY();
404 
405  return rv;
406 }
407 
408 /* helper functions for Python code execution */
409 
410 static PyObject *
412 {
413  PyObject *volatile arg = NULL;
414  PyObject *args;
415  int i;
416 
417  /*
418  * Make any Py*_New() calls before the PG_TRY block so that we can quickly
419  * return NULL on failure. We can't return within the PG_TRY block, else
420  * we'd miss unwinding the exception stack.
421  */
422  args = PyList_New(proc->nargs);
423  if (!args)
424  return NULL;
425 
426  PG_TRY();
427  {
428  for (i = 0; i < proc->nargs; i++)
429  {
430  PLyDatumToOb *arginfo = &proc->args[i];
431 
432  if (fcinfo->args[i].isnull)
433  arg = NULL;
434  else
435  arg = PLy_input_convert(arginfo, fcinfo->args[i].value);
436 
437  if (arg == NULL)
438  {
439  Py_INCREF(Py_None);
440  arg = Py_None;
441  }
442 
443  if (PyList_SetItem(args, i, arg) == -1)
444  PLy_elog(ERROR, "PyList_SetItem() failed, while setting up arguments");
445 
446  if (proc->argnames && proc->argnames[i] &&
447  PyDict_SetItemString(proc->globals, proc->argnames[i], arg) == -1)
448  PLy_elog(ERROR, "PyDict_SetItemString() failed, while setting up arguments");
449  arg = NULL;
450  }
451 
452  /* Set up output conversion for functions returning RECORD */
453  if (proc->result.typoid == RECORDOID)
454  {
455  TupleDesc desc;
456 
457  if (get_call_result_type(fcinfo, NULL, &desc) != TYPEFUNC_COMPOSITE)
458  ereport(ERROR,
459  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
460  errmsg("function returning record called in context "
461  "that cannot accept type record")));
462 
463  /* cache the output conversion functions */
464  PLy_output_setup_record(&proc->result, desc, proc);
465  }
466  }
467  PG_CATCH();
468  {
469  Py_XDECREF(arg);
470  Py_XDECREF(args);
471 
472  PG_RE_THROW();
473  }
474  PG_END_TRY();
475 
476  return args;
477 }
478 
479 /*
480  * Construct a PLySavedArgs struct representing the current values of the
481  * procedure's arguments in its globals dict. This can be used to restore
482  * those values when exiting a recursive call level or returning control to a
483  * set-returning function.
484  *
485  * This would not be necessary except for an ancient decision to make args
486  * available via the proc's globals :-( ... but we're stuck with that now.
487  */
488 static PLySavedArgs *
490 {
491  PLySavedArgs *result;
492 
493  /* saved args are always allocated in procedure's context */
494  result = (PLySavedArgs *)
496  offsetof(PLySavedArgs, namedargs) +
497  proc->nargs * sizeof(PyObject *));
498  result->nargs = proc->nargs;
499 
500  /* Fetch the "args" list */
501  result->args = PyDict_GetItemString(proc->globals, "args");
502  Py_XINCREF(result->args);
503 
504  /* Fetch all the named arguments */
505  if (proc->argnames)
506  {
507  int i;
508 
509  for (i = 0; i < result->nargs; i++)
510  {
511  if (proc->argnames[i])
512  {
513  result->namedargs[i] = PyDict_GetItemString(proc->globals,
514  proc->argnames[i]);
515  Py_XINCREF(result->namedargs[i]);
516  }
517  }
518  }
519 
520  return result;
521 }
522 
523 /*
524  * Restore procedure's arguments from a PLySavedArgs struct,
525  * then free the struct.
526  */
527 static void
529 {
530  /* Restore named arguments into their slots in the globals dict */
531  if (proc->argnames)
532  {
533  int i;
534 
535  for (i = 0; i < savedargs->nargs; i++)
536  {
537  if (proc->argnames[i] && savedargs->namedargs[i])
538  {
539  PyDict_SetItemString(proc->globals, proc->argnames[i],
540  savedargs->namedargs[i]);
541  Py_DECREF(savedargs->namedargs[i]);
542  }
543  }
544  }
545 
546  /* Restore the "args" object, too */
547  if (savedargs->args)
548  {
549  PyDict_SetItemString(proc->globals, "args", savedargs->args);
550  Py_DECREF(savedargs->args);
551  }
552 
553  /* And free the PLySavedArgs struct */
554  pfree(savedargs);
555 }
556 
557 /*
558  * Free a PLySavedArgs struct without restoring the values.
559  */
560 static void
562 {
563  int i;
564 
565  /* Drop references for named args */
566  for (i = 0; i < savedargs->nargs; i++)
567  {
568  Py_XDECREF(savedargs->namedargs[i]);
569  }
570 
571  /* Drop ref to the "args" object, too */
572  Py_XDECREF(savedargs->args);
573 
574  /* And free the PLySavedArgs struct */
575  pfree(savedargs);
576 }
577 
578 /*
579  * Save away any existing arguments for the given procedure, so that we can
580  * install new values for a recursive call. This should be invoked before
581  * doing PLy_function_build_args().
582  *
583  * NB: caller must ensure that PLy_global_args_pop gets invoked once, and
584  * only once, per successful completion of PLy_global_args_push. Otherwise
585  * we'll end up out-of-sync between the actual call stack and the contents
586  * of proc->argstack.
587  */
588 static void
590 {
591  /* We only need to push if we are already inside some active call */
592  if (proc->calldepth > 0)
593  {
594  PLySavedArgs *node;
595 
596  /* Build a struct containing current argument values */
597  node = PLy_function_save_args(proc);
598 
599  /*
600  * Push the saved argument values into the procedure's stack. Once we
601  * modify either proc->argstack or proc->calldepth, we had better
602  * return without the possibility of error.
603  */
604  node->next = proc->argstack;
605  proc->argstack = node;
606  }
607  proc->calldepth++;
608 }
609 
610 /*
611  * Pop old arguments when exiting a recursive call.
612  *
613  * Note: the idea here is to adjust the proc's callstack state before doing
614  * anything that could possibly fail. In event of any error, we want the
615  * callstack to look like we've done the pop. Leaking a bit of memory is
616  * tolerable.
617  */
618 static void
620 {
621  Assert(proc->calldepth > 0);
622  /* We only need to pop if we were already inside some active call */
623  if (proc->calldepth > 1)
624  {
625  PLySavedArgs *ptr = proc->argstack;
626 
627  /* Pop the callstack */
628  Assert(ptr != NULL);
629  proc->argstack = ptr->next;
630  proc->calldepth--;
631 
632  /* Restore argument values, then free ptr */
633  PLy_function_restore_args(proc, ptr);
634  }
635  else
636  {
637  /* Exiting call depth 1 */
638  Assert(proc->argstack == NULL);
639  proc->calldepth--;
640 
641  /*
642  * We used to delete the named arguments (but not "args") from the
643  * proc's globals dict when exiting the outermost call level for a
644  * function. This seems rather pointless though: nothing can see the
645  * dict until the function is called again, at which time we'll
646  * overwrite those dict entries. So don't bother with that.
647  */
648  }
649 }
650 
651 /*
652  * Memory context deletion callback for cleaning up a PLySRFState.
653  * We need this in case execution of the SRF is terminated early,
654  * due to error or the caller simply not running it to completion.
655  */
656 static void
658 {
659  PLySRFState *srfstate = (PLySRFState *) arg;
660 
661  /* Release refcount on the iter, if we still have one */
662  Py_XDECREF(srfstate->iter);
663  srfstate->iter = NULL;
664  /* And drop any saved args; we won't need them */
665  if (srfstate->savedargs)
667  srfstate->savedargs = NULL;
668 }
669 
670 static void
672 {
674 
675  if (exec_ctx->curr_proc &&
676  !exec_ctx->curr_proc->is_procedure)
677  errcontext("while creating return value");
678 }
679 
680 static PyObject *
682 {
683  TriggerData *tdata = (TriggerData *) fcinfo->context;
684  TupleDesc rel_descr = RelationGetDescr(tdata->tg_relation);
685  PyObject *pltname,
686  *pltevent,
687  *pltwhen,
688  *pltlevel,
689  *pltrelid,
690  *plttablename,
691  *plttableschema,
692  *pltargs = NULL,
693  *pytnew,
694  *pytold,
695  *pltdata;
696  char *stroid;
697 
698  /*
699  * Make any Py*_New() calls before the PG_TRY block so that we can quickly
700  * return NULL on failure. We can't return within the PG_TRY block, else
701  * we'd miss unwinding the exception stack.
702  */
703  pltdata = PyDict_New();
704  if (!pltdata)
705  return NULL;
706 
707  if (tdata->tg_trigger->tgnargs)
708  {
709  pltargs = PyList_New(tdata->tg_trigger->tgnargs);
710  if (!pltargs)
711  {
712  Py_DECREF(pltdata);
713  return NULL;
714  }
715  }
716 
717  PG_TRY();
718  {
719  pltname = PLyUnicode_FromString(tdata->tg_trigger->tgname);
720  PyDict_SetItemString(pltdata, "name", pltname);
721  Py_DECREF(pltname);
722 
725  pltrelid = PLyUnicode_FromString(stroid);
726  PyDict_SetItemString(pltdata, "relid", pltrelid);
727  Py_DECREF(pltrelid);
728  pfree(stroid);
729 
730  stroid = SPI_getrelname(tdata->tg_relation);
731  plttablename = PLyUnicode_FromString(stroid);
732  PyDict_SetItemString(pltdata, "table_name", plttablename);
733  Py_DECREF(plttablename);
734  pfree(stroid);
735 
736  stroid = SPI_getnspname(tdata->tg_relation);
737  plttableschema = PLyUnicode_FromString(stroid);
738  PyDict_SetItemString(pltdata, "table_schema", plttableschema);
739  Py_DECREF(plttableschema);
740  pfree(stroid);
741 
742  if (TRIGGER_FIRED_BEFORE(tdata->tg_event))
743  pltwhen = PLyUnicode_FromString("BEFORE");
744  else if (TRIGGER_FIRED_AFTER(tdata->tg_event))
745  pltwhen = PLyUnicode_FromString("AFTER");
746  else if (TRIGGER_FIRED_INSTEAD(tdata->tg_event))
747  pltwhen = PLyUnicode_FromString("INSTEAD OF");
748  else
749  {
750  elog(ERROR, "unrecognized WHEN tg_event: %u", tdata->tg_event);
751  pltwhen = NULL; /* keep compiler quiet */
752  }
753  PyDict_SetItemString(pltdata, "when", pltwhen);
754  Py_DECREF(pltwhen);
755 
756  if (TRIGGER_FIRED_FOR_ROW(tdata->tg_event))
757  {
758  pltlevel = PLyUnicode_FromString("ROW");
759  PyDict_SetItemString(pltdata, "level", pltlevel);
760  Py_DECREF(pltlevel);
761 
762  /*
763  * Note: In BEFORE trigger, stored generated columns are not
764  * computed yet, so don't make them accessible in NEW row.
765  */
766 
767  if (TRIGGER_FIRED_BY_INSERT(tdata->tg_event))
768  {
769  pltevent = PLyUnicode_FromString("INSERT");
770 
771  PyDict_SetItemString(pltdata, "old", Py_None);
772  pytnew = PLy_input_from_tuple(&proc->result_in,
773  tdata->tg_trigtuple,
774  rel_descr,
775  !TRIGGER_FIRED_BEFORE(tdata->tg_event));
776  PyDict_SetItemString(pltdata, "new", pytnew);
777  Py_DECREF(pytnew);
778  *rv = tdata->tg_trigtuple;
779  }
780  else if (TRIGGER_FIRED_BY_DELETE(tdata->tg_event))
781  {
782  pltevent = PLyUnicode_FromString("DELETE");
783 
784  PyDict_SetItemString(pltdata, "new", Py_None);
785  pytold = PLy_input_from_tuple(&proc->result_in,
786  tdata->tg_trigtuple,
787  rel_descr,
788  true);
789  PyDict_SetItemString(pltdata, "old", pytold);
790  Py_DECREF(pytold);
791  *rv = tdata->tg_trigtuple;
792  }
793  else if (TRIGGER_FIRED_BY_UPDATE(tdata->tg_event))
794  {
795  pltevent = PLyUnicode_FromString("UPDATE");
796 
797  pytnew = PLy_input_from_tuple(&proc->result_in,
798  tdata->tg_newtuple,
799  rel_descr,
800  !TRIGGER_FIRED_BEFORE(tdata->tg_event));
801  PyDict_SetItemString(pltdata, "new", pytnew);
802  Py_DECREF(pytnew);
803  pytold = PLy_input_from_tuple(&proc->result_in,
804  tdata->tg_trigtuple,
805  rel_descr,
806  true);
807  PyDict_SetItemString(pltdata, "old", pytold);
808  Py_DECREF(pytold);
809  *rv = tdata->tg_newtuple;
810  }
811  else
812  {
813  elog(ERROR, "unrecognized OP tg_event: %u", tdata->tg_event);
814  pltevent = NULL; /* keep compiler quiet */
815  }
816 
817  PyDict_SetItemString(pltdata, "event", pltevent);
818  Py_DECREF(pltevent);
819  }
820  else if (TRIGGER_FIRED_FOR_STATEMENT(tdata->tg_event))
821  {
822  pltlevel = PLyUnicode_FromString("STATEMENT");
823  PyDict_SetItemString(pltdata, "level", pltlevel);
824  Py_DECREF(pltlevel);
825 
826  PyDict_SetItemString(pltdata, "old", Py_None);
827  PyDict_SetItemString(pltdata, "new", Py_None);
828  *rv = NULL;
829 
830  if (TRIGGER_FIRED_BY_INSERT(tdata->tg_event))
831  pltevent = PLyUnicode_FromString("INSERT");
832  else if (TRIGGER_FIRED_BY_DELETE(tdata->tg_event))
833  pltevent = PLyUnicode_FromString("DELETE");
834  else if (TRIGGER_FIRED_BY_UPDATE(tdata->tg_event))
835  pltevent = PLyUnicode_FromString("UPDATE");
836  else if (TRIGGER_FIRED_BY_TRUNCATE(tdata->tg_event))
837  pltevent = PLyUnicode_FromString("TRUNCATE");
838  else
839  {
840  elog(ERROR, "unrecognized OP tg_event: %u", tdata->tg_event);
841  pltevent = NULL; /* keep compiler quiet */
842  }
843 
844  PyDict_SetItemString(pltdata, "event", pltevent);
845  Py_DECREF(pltevent);
846  }
847  else
848  elog(ERROR, "unrecognized LEVEL tg_event: %u", tdata->tg_event);
849 
850  if (tdata->tg_trigger->tgnargs)
851  {
852  /*
853  * all strings...
854  */
855  int i;
856  PyObject *pltarg;
857 
858  /* pltargs should have been allocated before the PG_TRY block. */
859  Assert(pltargs);
860 
861  for (i = 0; i < tdata->tg_trigger->tgnargs; i++)
862  {
863  pltarg = PLyUnicode_FromString(tdata->tg_trigger->tgargs[i]);
864 
865  /*
866  * stolen, don't Py_DECREF
867  */
868  PyList_SetItem(pltargs, i, pltarg);
869  }
870  }
871  else
872  {
873  Py_INCREF(Py_None);
874  pltargs = Py_None;
875  }
876  PyDict_SetItemString(pltdata, "args", pltargs);
877  Py_DECREF(pltargs);
878  }
879  PG_CATCH();
880  {
881  Py_XDECREF(pltargs);
882  Py_XDECREF(pltdata);
883  PG_RE_THROW();
884  }
885  PG_END_TRY();
886 
887  return pltdata;
888 }
889 
890 /*
891  * Apply changes requested by a MODIFY return from a trigger function.
892  */
893 static HeapTuple
894 PLy_modify_tuple(PLyProcedure *proc, PyObject *pltd, TriggerData *tdata,
895  HeapTuple otup)
896 {
897  HeapTuple rtup;
898  PyObject *volatile plntup;
899  PyObject *volatile plkeys;
900  PyObject *volatile plval;
901  Datum *volatile modvalues;
902  bool *volatile modnulls;
903  bool *volatile modrepls;
904  ErrorContextCallback plerrcontext;
905 
907  plerrcontext.previous = error_context_stack;
908  error_context_stack = &plerrcontext;
909 
910  plntup = plkeys = plval = NULL;
911  modvalues = NULL;
912  modnulls = NULL;
913  modrepls = NULL;
914 
915  PG_TRY();
916  {
917  TupleDesc tupdesc;
918  int nkeys,
919  i;
920 
921  if ((plntup = PyDict_GetItemString(pltd, "new")) == NULL)
922  ereport(ERROR,
923  (errcode(ERRCODE_UNDEFINED_OBJECT),
924  errmsg("TD[\"new\"] deleted, cannot modify row")));
925  Py_INCREF(plntup);
926  if (!PyDict_Check(plntup))
927  ereport(ERROR,
928  (errcode(ERRCODE_DATATYPE_MISMATCH),
929  errmsg("TD[\"new\"] is not a dictionary")));
930 
931  plkeys = PyDict_Keys(plntup);
932  nkeys = PyList_Size(plkeys);
933 
934  tupdesc = RelationGetDescr(tdata->tg_relation);
935 
936  modvalues = (Datum *) palloc0(tupdesc->natts * sizeof(Datum));
937  modnulls = (bool *) palloc0(tupdesc->natts * sizeof(bool));
938  modrepls = (bool *) palloc0(tupdesc->natts * sizeof(bool));
939 
940  for (i = 0; i < nkeys; i++)
941  {
942  PyObject *platt;
943  char *plattstr;
944  int attn;
945  PLyObToDatum *att;
946 
947  platt = PyList_GetItem(plkeys, i);
948  if (PyUnicode_Check(platt))
949  plattstr = PLyUnicode_AsString(platt);
950  else
951  {
952  ereport(ERROR,
953  (errcode(ERRCODE_DATATYPE_MISMATCH),
954  errmsg("TD[\"new\"] dictionary key at ordinal position %d is not a string", i)));
955  plattstr = NULL; /* keep compiler quiet */
956  }
957  attn = SPI_fnumber(tupdesc, plattstr);
958  if (attn == SPI_ERROR_NOATTRIBUTE)
959  ereport(ERROR,
960  (errcode(ERRCODE_UNDEFINED_COLUMN),
961  errmsg("key \"%s\" found in TD[\"new\"] does not exist as a column in the triggering row",
962  plattstr)));
963  if (attn <= 0)
964  ereport(ERROR,
965  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
966  errmsg("cannot set system attribute \"%s\"",
967  plattstr)));
968  if (TupleDescAttr(tupdesc, attn - 1)->attgenerated)
969  ereport(ERROR,
970  (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
971  errmsg("cannot set generated column \"%s\"",
972  plattstr)));
973 
974  plval = PyDict_GetItem(plntup, platt);
975  if (plval == NULL)
976  elog(FATAL, "Python interpreter is probably corrupted");
977 
978  Py_INCREF(plval);
979 
980  /* We assume proc->result is set up to convert tuples properly */
981  att = &proc->result.u.tuple.atts[attn - 1];
982 
983  modvalues[attn - 1] = PLy_output_convert(att,
984  plval,
985  &modnulls[attn - 1]);
986  modrepls[attn - 1] = true;
987 
988  Py_DECREF(plval);
989  plval = NULL;
990  }
991 
992  rtup = heap_modify_tuple(otup, tupdesc, modvalues, modnulls, modrepls);
993  }
994  PG_CATCH();
995  {
996  Py_XDECREF(plntup);
997  Py_XDECREF(plkeys);
998  Py_XDECREF(plval);
999 
1000  if (modvalues)
1001  pfree(modvalues);
1002  if (modnulls)
1003  pfree(modnulls);
1004  if (modrepls)
1005  pfree(modrepls);
1006 
1007  PG_RE_THROW();
1008  }
1009  PG_END_TRY();
1010 
1011  Py_DECREF(plntup);
1012  Py_DECREF(plkeys);
1013 
1014  pfree(modvalues);
1015  pfree(modnulls);
1016  pfree(modrepls);
1017 
1018  error_context_stack = plerrcontext.previous;
1019 
1020  return rtup;
1021 }
1022 
1023 static void
1025 {
1027 
1028  if (exec_ctx->curr_proc)
1029  errcontext("while modifying trigger row");
1030 }
1031 
1032 /* execute Python code, propagate Python errors to the backend */
1033 static PyObject *
1034 PLy_procedure_call(PLyProcedure *proc, const char *kargs, PyObject *vargs)
1035 {
1036  PyObject *rv = NULL;
1037  int volatile save_subxact_level = list_length(explicit_subtransactions);
1038 
1039  PyDict_SetItemString(proc->globals, kargs, vargs);
1040 
1041  PG_TRY();
1042  {
1043 #if PY_VERSION_HEX >= 0x03020000
1044  rv = PyEval_EvalCode(proc->code,
1045  proc->globals, proc->globals);
1046 #else
1047  rv = PyEval_EvalCode((PyCodeObject *) proc->code,
1048  proc->globals, proc->globals);
1049 #endif
1050 
1051  /*
1052  * Since plpy will only let you close subtransactions that you
1053  * started, you cannot *unnest* subtransactions, only *nest* them
1054  * without closing.
1055  */
1056  Assert(list_length(explicit_subtransactions) >= save_subxact_level);
1057  }
1058  PG_FINALLY();
1059  {
1060  PLy_abort_open_subtransactions(save_subxact_level);
1061  }
1062  PG_END_TRY();
1063 
1064  /* If the Python code returned an error, propagate it */
1065  if (rv == NULL)
1066  PLy_elog(ERROR, NULL);
1067 
1068  return rv;
1069 }
1070 
1071 /*
1072  * Abort lingering subtransactions that have been explicitly started
1073  * by plpy.subtransaction().start() and not properly closed.
1074  */
1075 static void
1076 PLy_abort_open_subtransactions(int save_subxact_level)
1077 {
1078  Assert(save_subxact_level >= 0);
1079 
1080  while (list_length(explicit_subtransactions) > save_subxact_level)
1081  {
1082  PLySubtransactionData *subtransactiondata;
1083 
1085 
1086  ereport(WARNING,
1087  (errmsg("forcibly aborting a subtransaction that has not been exited")));
1088 
1090 
1091  subtransactiondata = (PLySubtransactionData *) linitial(explicit_subtransactions);
1093 
1094  MemoryContextSwitchTo(subtransactiondata->oldcontext);
1095  CurrentResourceOwner = subtransactiondata->oldowner;
1096  pfree(subtransactiondata);
1097  }
1098 }
#define PG_USED_FOR_ASSERTS_ONLY
Definition: c.h:166
int errdetail(const char *fmt,...)
Definition: elog.c:1202
ErrorContextCallback * error_context_stack
Definition: elog.c:95
int errcode(int sqlerrcode)
Definition: elog.c:858
int errmsg(const char *fmt,...)
Definition: elog.c:1069
#define PG_RE_THROW()
Definition: elog.h:411
#define errcontext
Definition: elog.h:196
#define FATAL
Definition: elog.h:41
#define PG_TRY(...)
Definition: elog.h:370
#define WARNING
Definition: elog.h:36
#define PG_END_TRY(...)
Definition: elog.h:395
#define ERROR
Definition: elog.h:39
#define PG_CATCH(...)
Definition: elog.h:380
#define PG_FINALLY(...)
Definition: elog.h:387
#define ereport(elevel,...)
Definition: elog.h:149
@ SFRM_ValuePerCall
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#define DirectFunctionCall1(func, arg1)
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TypeFuncClass get_call_result_type(FunctionCallInfo fcinfo, Oid *resultTypeId, TupleDesc *resultTupleDesc)
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#define SRF_IS_FIRSTCALL()
Definition: funcapi.h:304
#define SRF_RETURN_NEXT_NULL(_funcctx)
Definition: funcapi.h:319
#define SRF_PERCALL_SETUP()
Definition: funcapi.h:308
@ TYPEFUNC_COMPOSITE
Definition: funcapi.h:149
#define SRF_RETURN_NEXT(_funcctx, _result)
Definition: funcapi.h:310
#define SRF_FIRSTCALL_INIT()
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#define SRF_RETURN_DONE(_funcctx)
Definition: funcapi.h:328
HeapTuple heap_modify_tuple(HeapTuple tuple, TupleDesc tupleDesc, Datum *replValues, bool *replIsnull, bool *doReplace)
Definition: heaptuple.c:1113
int i
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if(TABLE==NULL||TABLE_index==NULL)
Definition: isn.c:77
#define PLy_elog
Assert(fmt[strlen(fmt) - 1] !='\n')
List * list_delete_first(List *list)
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void MemoryContextRegisterResetCallback(MemoryContext context, MemoryContextCallback *cb)
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void pfree(void *pointer)
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void * palloc0(Size size)
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void * MemoryContextAllocZero(MemoryContext context, Size size)
Definition: mcxt.c:1064
#define IsA(nodeptr, _type_)
Definition: nodes.h:179
Datum oidout(PG_FUNCTION_ARGS)
Definition: oid.c:46
static MemoryContext MemoryContextSwitchTo(MemoryContext context)
Definition: palloc.h:138
void * arg
static int list_length(const List *l)
Definition: pg_list.h:152
#define NIL
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#define linitial(l)
Definition: pg_list.h:178
static void PLy_function_drop_args(PLySavedArgs *savedargs)
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static void PLy_global_args_push(PLyProcedure *proc)
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struct PLySRFState PLySRFState
Datum PLy_exec_function(FunctionCallInfo fcinfo, PLyProcedure *proc)
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static PyObject * PLy_function_build_args(FunctionCallInfo fcinfo, PLyProcedure *proc)
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static void PLy_function_restore_args(PLyProcedure *proc, PLySavedArgs *savedargs)
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static PyObject * PLy_procedure_call(PLyProcedure *proc, const char *kargs, PyObject *vargs)
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static void plpython_trigger_error_callback(void *arg)
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static void PLy_global_args_pop(PLyProcedure *proc)
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static PyObject * PLy_trigger_build_args(FunctionCallInfo fcinfo, PLyProcedure *proc, HeapTuple *rv)
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static HeapTuple PLy_modify_tuple(PLyProcedure *proc, PyObject *pltd, TriggerData *tdata, HeapTuple otup)
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Definition: plpy_exec.c:657
static PLySavedArgs * PLy_function_save_args(PLyProcedure *proc)
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static void plpython_return_error_callback(void *arg)
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List * explicit_subtransactions
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union PLyObToDatum::@170 u
PLyObToDatum * atts
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PyObject * code
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Definition: trigger.h:38
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Definition: reltrigger.h:38
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Definition: trigger.h:125
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Definition: trigger.h:113
#define TRIGGER_FIRED_BEFORE(event)
Definition: trigger.h:128
#define CALLED_AS_TRIGGER(fcinfo)
Definition: trigger.h:26
#define TRIGGER_FIRED_FOR_ROW(event)
Definition: trigger.h:122
#define TRIGGER_FIRED_AFTER(event)
Definition: trigger.h:131
#define TRIGGER_FIRED_BY_TRUNCATE(event)
Definition: trigger.h:119
#define TRIGGER_FIRED_BY_INSERT(event)
Definition: trigger.h:110
#define TRIGGER_FIRED_BY_UPDATE(event)
Definition: trigger.h:116
#define TRIGGER_FIRED_INSTEAD(event)
Definition: trigger.h:134
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