1 /*-------------------------------------------------------------------------
2 *
3 * fastpath.c
4 * routines to handle function requests from the frontend
5 *
6 * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
8 *
9 *
10 * IDENTIFICATION
11 * src/backend/tcop/fastpath.c
12 *
13 * NOTES
14 * This cruft is the server side of PQfn.
15 *
16 *-------------------------------------------------------------------------
17 */
18 #include "postgres.h"
19
20 #include "access/htup_details.h"
21 #include "access/xact.h"
22 #include "catalog/objectaccess.h"
23 #include "catalog/pg_proc.h"
24 #include "libpq/libpq.h"
25 #include "libpq/pqformat.h"
26 #include "mb/pg_wchar.h"
27 #include "miscadmin.h"
28 #include "port/pg_bswap.h"
29 #include "tcop/fastpath.h"
30 #include "tcop/tcopprot.h"
31 #include "utils/acl.h"
32 #include "utils/lsyscache.h"
33 #include "utils/snapmgr.h"
34 #include "utils/syscache.h"
35
36
37 /*
38 * Formerly, this code attempted to cache the function and type info
39 * looked up by fetch_fp_info, but only for the duration of a single
40 * transaction command (since in theory the info could change between
41 * commands). This was utterly useless, because postgres.c executes
42 * each fastpath call as a separate transaction command, and so the
43 * cached data could never actually have been reused. If it had worked
44 * as intended, it would have had problems anyway with dangling references
45 * in the FmgrInfo struct. So, forget about caching and just repeat the
46 * syscache fetches on each usage. They're not *that* expensive.
47 */
48 struct fp_info
49 {
50 Oid funcid;
51 FmgrInfo flinfo; /* function lookup info for funcid */
52 Oid namespace; /* other stuff from pg_proc */
53 Oid rettype;
54 Oid argtypes[FUNC_MAX_ARGS];
55 char fname[NAMEDATALEN]; /* function name for logging */
56 };
57
58
59 static int16 parse_fcall_arguments(StringInfo msgBuf, struct fp_info *fip,
60 FunctionCallInfo fcinfo);
61 static int16 parse_fcall_arguments_20(StringInfo msgBuf, struct fp_info *fip,
62 FunctionCallInfo fcinfo);
63
64
65 /* ----------------
66 * GetOldFunctionMessage
67 *
68 * In pre-3.0 protocol, there is no length word on the message, so we have
69 * to have code that understands the message layout to absorb the message
70 * into a buffer. We want to do this before we start execution, so that
71 * we do not lose sync with the frontend if there's an error.
72 *
73 * The caller should already have initialized buf to empty.
74 * ----------------
75 */
76 int
GetOldFunctionMessage(StringInfo buf)77 GetOldFunctionMessage(StringInfo buf)
78 {
79 int32 ibuf;
80 int nargs;
81
82 /* Dummy string argument */
83 if (pq_getstring(buf))
84 return EOF;
85 /* Function OID */
86 if (pq_getbytes((char *) &ibuf, 4))
87 return EOF;
88 appendBinaryStringInfo(buf, (char *) &ibuf, 4);
89 /* Number of arguments */
90 if (pq_getbytes((char *) &ibuf, 4))
91 return EOF;
92 appendBinaryStringInfo(buf, (char *) &ibuf, 4);
93 nargs = pg_ntoh32(ibuf);
94 /* For each argument ... */
95 while (nargs-- > 0)
96 {
97 int argsize;
98
99 /* argsize */
100 if (pq_getbytes((char *) &ibuf, 4))
101 return EOF;
102 appendBinaryStringInfo(buf, (char *) &ibuf, 4);
103 argsize = pg_ntoh32(ibuf);
104 if (argsize < -1)
105 {
106 /* FATAL here since no hope of regaining message sync */
107 ereport(FATAL,
108 (errcode(ERRCODE_PROTOCOL_VIOLATION),
109 errmsg("invalid argument size %d in function call message",
110 argsize)));
111 }
112 /* and arg contents */
113 if (argsize > 0)
114 {
115 /* Allocate space for arg */
116 enlargeStringInfo(buf, argsize);
117 /* And grab it */
118 if (pq_getbytes(buf->data + buf->len, argsize))
119 return EOF;
120 buf->len += argsize;
121 /* Place a trailing null per StringInfo convention */
122 buf->data[buf->len] = '\0';
123 }
124 }
125 return 0;
126 }
127
128 /* ----------------
129 * SendFunctionResult
130 *
131 * Note: although this routine doesn't check, the format had better be 1
132 * (binary) when talking to a pre-3.0 client.
133 * ----------------
134 */
135 static void
SendFunctionResult(Datum retval,bool isnull,Oid rettype,int16 format)136 SendFunctionResult(Datum retval, bool isnull, Oid rettype, int16 format)
137 {
138 bool newstyle = (PG_PROTOCOL_MAJOR(FrontendProtocol) >= 3);
139 StringInfoData buf;
140
141 pq_beginmessage(&buf, 'V');
142
143 if (isnull)
144 {
145 if (newstyle)
146 pq_sendint32(&buf, -1);
147 }
148 else
149 {
150 if (!newstyle)
151 pq_sendbyte(&buf, 'G');
152
153 if (format == 0)
154 {
155 Oid typoutput;
156 bool typisvarlena;
157 char *outputstr;
158
159 getTypeOutputInfo(rettype, &typoutput, &typisvarlena);
160 outputstr = OidOutputFunctionCall(typoutput, retval);
161 pq_sendcountedtext(&buf, outputstr, strlen(outputstr), false);
162 pfree(outputstr);
163 }
164 else if (format == 1)
165 {
166 Oid typsend;
167 bool typisvarlena;
168 bytea *outputbytes;
169
170 getTypeBinaryOutputInfo(rettype, &typsend, &typisvarlena);
171 outputbytes = OidSendFunctionCall(typsend, retval);
172 pq_sendint32(&buf, VARSIZE(outputbytes) - VARHDRSZ);
173 pq_sendbytes(&buf, VARDATA(outputbytes),
174 VARSIZE(outputbytes) - VARHDRSZ);
175 pfree(outputbytes);
176 }
177 else
178 ereport(ERROR,
179 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
180 errmsg("unsupported format code: %d", format)));
181 }
182
183 if (!newstyle)
184 pq_sendbyte(&buf, '0');
185
186 pq_endmessage(&buf);
187 }
188
189 /*
190 * fetch_fp_info
191 *
192 * Performs catalog lookups to load a struct fp_info 'fip' for the
193 * function 'func_id'.
194 */
195 static void
fetch_fp_info(Oid func_id,struct fp_info * fip)196 fetch_fp_info(Oid func_id, struct fp_info *fip)
197 {
198 HeapTuple func_htp;
199 Form_pg_proc pp;
200
201 Assert(fip != NULL);
202
203 /*
204 * Since the validity of this structure is determined by whether the
205 * funcid is OK, we clear the funcid here. It must not be set to the
206 * correct value until we are about to return with a good struct fp_info,
207 * since we can be interrupted (i.e., with an ereport(ERROR, ...)) at any
208 * time. [No longer really an issue since we don't save the struct
209 * fp_info across transactions anymore, but keep it anyway.]
210 */
211 MemSet(fip, 0, sizeof(struct fp_info));
212 fip->funcid = InvalidOid;
213
214 func_htp = SearchSysCache1(PROCOID, ObjectIdGetDatum(func_id));
215 if (!HeapTupleIsValid(func_htp))
216 ereport(ERROR,
217 (errcode(ERRCODE_UNDEFINED_FUNCTION),
218 errmsg("function with OID %u does not exist", func_id)));
219 pp = (Form_pg_proc) GETSTRUCT(func_htp);
220
221 /* reject pg_proc entries that are unsafe to call via fastpath */
222 if (pp->prokind != PROKIND_FUNCTION || pp->proretset)
223 ereport(ERROR,
224 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
225 errmsg("cannot call function %s via fastpath interface",
226 NameStr(pp->proname))));
227
228 /* watch out for catalog entries with more than FUNC_MAX_ARGS args */
229 if (pp->pronargs > FUNC_MAX_ARGS)
230 elog(ERROR, "function %s has more than %d arguments",
231 NameStr(pp->proname), FUNC_MAX_ARGS);
232
233 fip->namespace = pp->pronamespace;
234 fip->rettype = pp->prorettype;
235 memcpy(fip->argtypes, pp->proargtypes.values, pp->pronargs * sizeof(Oid));
236 strlcpy(fip->fname, NameStr(pp->proname), NAMEDATALEN);
237
238 ReleaseSysCache(func_htp);
239
240 fmgr_info(func_id, &fip->flinfo);
241
242 /*
243 * This must be last!
244 */
245 fip->funcid = func_id;
246 }
247
248
249 /*
250 * HandleFunctionRequest
251 *
252 * Server side of PQfn (fastpath function calls from the frontend).
253 * This corresponds to the libpq protocol symbol "F".
254 *
255 * INPUT:
256 * postgres.c has already read the message body and will pass it in
257 * msgBuf.
258 *
259 * Note: palloc()s done here and in the called function do not need to be
260 * cleaned up explicitly. We are called from PostgresMain() in the
261 * MessageContext memory context, which will be automatically reset when
262 * control returns to PostgresMain.
263 */
264 void
HandleFunctionRequest(StringInfo msgBuf)265 HandleFunctionRequest(StringInfo msgBuf)
266 {
267 LOCAL_FCINFO(fcinfo, FUNC_MAX_ARGS);
268 Oid fid;
269 AclResult aclresult;
270 int16 rformat;
271 Datum retval;
272 struct fp_info my_fp;
273 struct fp_info *fip;
274 bool callit;
275 bool was_logged = false;
276 char msec_str[32];
277
278 /*
279 * We only accept COMMIT/ABORT if we are in an aborted transaction, and
280 * COMMIT/ABORT cannot be executed through the fastpath interface.
281 */
282 if (IsAbortedTransactionBlockState())
283 ereport(ERROR,
284 (errcode(ERRCODE_IN_FAILED_SQL_TRANSACTION),
285 errmsg("current transaction is aborted, "
286 "commands ignored until end of transaction block")));
287
288 /*
289 * Now that we know we are in a valid transaction, set snapshot in case
290 * needed by function itself or one of the datatype I/O routines.
291 */
292 PushActiveSnapshot(GetTransactionSnapshot());
293
294 /*
295 * Begin parsing the buffer contents.
296 */
297 if (PG_PROTOCOL_MAJOR(FrontendProtocol) < 3)
298 (void) pq_getmsgstring(msgBuf); /* dummy string */
299
300 fid = (Oid) pq_getmsgint(msgBuf, 4); /* function oid */
301
302 /*
303 * There used to be a lame attempt at caching lookup info here. Now we
304 * just do the lookups on every call.
305 */
306 fip = &my_fp;
307 fetch_fp_info(fid, fip);
308
309 /* Log as soon as we have the function OID and name */
310 if (log_statement == LOGSTMT_ALL)
311 {
312 ereport(LOG,
313 (errmsg("fastpath function call: \"%s\" (OID %u)",
314 fip->fname, fid)));
315 was_logged = true;
316 }
317
318 /*
319 * Check permission to access and call function. Since we didn't go
320 * through a normal name lookup, we need to check schema usage too.
321 */
322 aclresult = pg_namespace_aclcheck(fip->namespace, GetUserId(), ACL_USAGE);
323 if (aclresult != ACLCHECK_OK)
324 aclcheck_error(aclresult, OBJECT_SCHEMA,
325 get_namespace_name(fip->namespace));
326 InvokeNamespaceSearchHook(fip->namespace, true);
327
328 aclresult = pg_proc_aclcheck(fid, GetUserId(), ACL_EXECUTE);
329 if (aclresult != ACLCHECK_OK)
330 aclcheck_error(aclresult, OBJECT_FUNCTION,
331 get_func_name(fid));
332 InvokeFunctionExecuteHook(fid);
333
334 /*
335 * Prepare function call info block and insert arguments.
336 *
337 * Note: for now we pass collation = InvalidOid, so collation-sensitive
338 * functions can't be called this way. Perhaps we should pass
339 * DEFAULT_COLLATION_OID, instead?
340 */
341 InitFunctionCallInfoData(*fcinfo, &fip->flinfo, 0, InvalidOid, NULL, NULL);
342
343 if (PG_PROTOCOL_MAJOR(FrontendProtocol) >= 3)
344 rformat = parse_fcall_arguments(msgBuf, fip, fcinfo);
345 else
346 rformat = parse_fcall_arguments_20(msgBuf, fip, fcinfo);
347
348 /* Verify we reached the end of the message where expected. */
349 pq_getmsgend(msgBuf);
350
351 /*
352 * If func is strict, must not call it for null args.
353 */
354 callit = true;
355 if (fip->flinfo.fn_strict)
356 {
357 int i;
358
359 for (i = 0; i < fcinfo->nargs; i++)
360 {
361 if (fcinfo->args[i].isnull)
362 {
363 callit = false;
364 break;
365 }
366 }
367 }
368
369 if (callit)
370 {
371 /* Okay, do it ... */
372 retval = FunctionCallInvoke(fcinfo);
373 }
374 else
375 {
376 fcinfo->isnull = true;
377 retval = (Datum) 0;
378 }
379
380 /* ensure we do at least one CHECK_FOR_INTERRUPTS per function call */
381 CHECK_FOR_INTERRUPTS();
382
383 SendFunctionResult(retval, fcinfo->isnull, fip->rettype, rformat);
384
385 /* We no longer need the snapshot */
386 PopActiveSnapshot();
387
388 /*
389 * Emit duration logging if appropriate.
390 */
391 switch (check_log_duration(msec_str, was_logged))
392 {
393 case 1:
394 ereport(LOG,
395 (errmsg("duration: %s ms", msec_str)));
396 break;
397 case 2:
398 ereport(LOG,
399 (errmsg("duration: %s ms fastpath function call: \"%s\" (OID %u)",
400 msec_str, fip->fname, fid)));
401 break;
402 }
403 }
404
405 /*
406 * Parse function arguments in a 3.0 protocol message
407 *
408 * Argument values are loaded into *fcinfo, and the desired result format
409 * is returned.
410 */
411 static int16
parse_fcall_arguments(StringInfo msgBuf,struct fp_info * fip,FunctionCallInfo fcinfo)412 parse_fcall_arguments(StringInfo msgBuf, struct fp_info *fip,
413 FunctionCallInfo fcinfo)
414 {
415 int nargs;
416 int i;
417 int numAFormats;
418 int16 *aformats = NULL;
419 StringInfoData abuf;
420
421 /* Get the argument format codes */
422 numAFormats = pq_getmsgint(msgBuf, 2);
423 if (numAFormats > 0)
424 {
425 aformats = (int16 *) palloc(numAFormats * sizeof(int16));
426 for (i = 0; i < numAFormats; i++)
427 aformats[i] = pq_getmsgint(msgBuf, 2);
428 }
429
430 nargs = pq_getmsgint(msgBuf, 2); /* # of arguments */
431
432 if (fip->flinfo.fn_nargs != nargs || nargs > FUNC_MAX_ARGS)
433 ereport(ERROR,
434 (errcode(ERRCODE_PROTOCOL_VIOLATION),
435 errmsg("function call message contains %d arguments but function requires %d",
436 nargs, fip->flinfo.fn_nargs)));
437
438 fcinfo->nargs = nargs;
439
440 if (numAFormats > 1 && numAFormats != nargs)
441 ereport(ERROR,
442 (errcode(ERRCODE_PROTOCOL_VIOLATION),
443 errmsg("function call message contains %d argument formats but %d arguments",
444 numAFormats, nargs)));
445
446 initStringInfo(&abuf);
447
448 /*
449 * Copy supplied arguments into arg vector.
450 */
451 for (i = 0; i < nargs; ++i)
452 {
453 int argsize;
454 int16 aformat;
455
456 argsize = pq_getmsgint(msgBuf, 4);
457 if (argsize == -1)
458 {
459 fcinfo->args[i].isnull = true;
460 }
461 else
462 {
463 fcinfo->args[i].isnull = false;
464 if (argsize < 0)
465 ereport(ERROR,
466 (errcode(ERRCODE_PROTOCOL_VIOLATION),
467 errmsg("invalid argument size %d in function call message",
468 argsize)));
469
470 /* Reset abuf to empty, and insert raw data into it */
471 resetStringInfo(&abuf);
472 appendBinaryStringInfo(&abuf,
473 pq_getmsgbytes(msgBuf, argsize),
474 argsize);
475 }
476
477 if (numAFormats > 1)
478 aformat = aformats[i];
479 else if (numAFormats > 0)
480 aformat = aformats[0];
481 else
482 aformat = 0; /* default = text */
483
484 if (aformat == 0)
485 {
486 Oid typinput;
487 Oid typioparam;
488 char *pstring;
489
490 getTypeInputInfo(fip->argtypes[i], &typinput, &typioparam);
491
492 /*
493 * Since stringinfo.c keeps a trailing null in place even for
494 * binary data, the contents of abuf are a valid C string. We
495 * have to do encoding conversion before calling the typinput
496 * routine, though.
497 */
498 if (argsize == -1)
499 pstring = NULL;
500 else
501 pstring = pg_client_to_server(abuf.data, argsize);
502
503 fcinfo->args[i].value = OidInputFunctionCall(typinput, pstring,
504 typioparam, -1);
505 /* Free result of encoding conversion, if any */
506 if (pstring && pstring != abuf.data)
507 pfree(pstring);
508 }
509 else if (aformat == 1)
510 {
511 Oid typreceive;
512 Oid typioparam;
513 StringInfo bufptr;
514
515 /* Call the argument type's binary input converter */
516 getTypeBinaryInputInfo(fip->argtypes[i], &typreceive, &typioparam);
517
518 if (argsize == -1)
519 bufptr = NULL;
520 else
521 bufptr = &abuf;
522
523 fcinfo->args[i].value = OidReceiveFunctionCall(typreceive, bufptr,
524 typioparam, -1);
525
526 /* Trouble if it didn't eat the whole buffer */
527 if (argsize != -1 && abuf.cursor != abuf.len)
528 ereport(ERROR,
529 (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
530 errmsg("incorrect binary data format in function argument %d",
531 i + 1)));
532 }
533 else
534 ereport(ERROR,
535 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
536 errmsg("unsupported format code: %d", aformat)));
537 }
538
539 /* Return result format code */
540 return (int16) pq_getmsgint(msgBuf, 2);
541 }
542
543 /*
544 * Parse function arguments in a 2.0 protocol message
545 *
546 * Argument values are loaded into *fcinfo, and the desired result format
547 * is returned.
548 */
549 static int16
parse_fcall_arguments_20(StringInfo msgBuf,struct fp_info * fip,FunctionCallInfo fcinfo)550 parse_fcall_arguments_20(StringInfo msgBuf, struct fp_info *fip,
551 FunctionCallInfo fcinfo)
552 {
553 int nargs;
554 int i;
555 StringInfoData abuf;
556
557 nargs = pq_getmsgint(msgBuf, 4); /* # of arguments */
558
559 if (fip->flinfo.fn_nargs != nargs || nargs > FUNC_MAX_ARGS)
560 ereport(ERROR,
561 (errcode(ERRCODE_PROTOCOL_VIOLATION),
562 errmsg("function call message contains %d arguments but function requires %d",
563 nargs, fip->flinfo.fn_nargs)));
564
565 fcinfo->nargs = nargs;
566
567 initStringInfo(&abuf);
568
569 /*
570 * Copy supplied arguments into arg vector. In protocol 2.0 these are
571 * always assumed to be supplied in binary format.
572 *
573 * Note: although the original protocol 2.0 code did not have any way for
574 * the frontend to specify a NULL argument, we now choose to interpret
575 * length == -1 as meaning a NULL.
576 */
577 for (i = 0; i < nargs; ++i)
578 {
579 int argsize;
580 Oid typreceive;
581 Oid typioparam;
582
583 getTypeBinaryInputInfo(fip->argtypes[i], &typreceive, &typioparam);
584
585 argsize = pq_getmsgint(msgBuf, 4);
586 if (argsize == -1)
587 {
588 fcinfo->args[i].isnull = true;
589 fcinfo->args[i].value = OidReceiveFunctionCall(typreceive, NULL,
590 typioparam, -1);
591 continue;
592 }
593 fcinfo->args[i].isnull = false;
594 if (argsize < 0)
595 ereport(ERROR,
596 (errcode(ERRCODE_PROTOCOL_VIOLATION),
597 errmsg("invalid argument size %d in function call message",
598 argsize)));
599
600 /* Reset abuf to empty, and insert raw data into it */
601 resetStringInfo(&abuf);
602 appendBinaryStringInfo(&abuf,
603 pq_getmsgbytes(msgBuf, argsize),
604 argsize);
605
606 fcinfo->args[i].value = OidReceiveFunctionCall(typreceive, &abuf,
607 typioparam, -1);
608
609 /* Trouble if it didn't eat the whole buffer */
610 if (abuf.cursor != abuf.len)
611 ereport(ERROR,
612 (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
613 errmsg("incorrect binary data format in function argument %d",
614 i + 1)));
615 }
616
617 /* Desired result format is always binary in protocol 2.0 */
618 return 1;
619 }
620