1/*-------------------------------------------------------------------------
2 *
3 * fastpath.c
4 * routines to handle function requests from the frontend
5 *
6 * Portions Copyright (c) 1996-2019, 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 */
48struct 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
59static int16 parse_fcall_arguments(StringInfo msgBuf, struct fp_info *fip,
60 FunctionCallInfo fcinfo);
61static 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 */
76int
77GetOldFunctionMessage(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 */
135static void
136SendFunctionResult(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 */
195static void
196fetch_fp_info(Oid func_id, struct fp_info *fip)
197{
198 HeapTuple func_htp;
199 Form_pg_proc pp;
200
201 Assert(OidIsValid(func_id));
202 Assert(fip != NULL);
203
204 /*
205 * Since the validity of this structure is determined by whether the
206 * funcid is OK, we clear the funcid here. It must not be set to the
207 * correct value until we are about to return with a good struct fp_info,
208 * since we can be interrupted (i.e., with an ereport(ERROR, ...)) at any
209 * time. [No longer really an issue since we don't save the struct
210 * fp_info across transactions anymore, but keep it anyway.]
211 */
212 MemSet(fip, 0, sizeof(struct fp_info));
213 fip->funcid = InvalidOid;
214
215 fmgr_info(func_id, &fip->flinfo);
216
217 func_htp = SearchSysCache1(PROCOID, ObjectIdGetDatum(func_id));
218 if (!HeapTupleIsValid(func_htp))
219 ereport(ERROR,
220 (errcode(ERRCODE_UNDEFINED_FUNCTION),
221 errmsg("function with OID %u does not exist", func_id)));
222 pp = (Form_pg_proc) GETSTRUCT(func_htp);
223
224 /* watch out for catalog entries with more than FUNC_MAX_ARGS args */
225 if (pp->pronargs > FUNC_MAX_ARGS)
226 elog(ERROR, "function %s has more than %d arguments",
227 NameStr(pp->proname), FUNC_MAX_ARGS);
228
229 fip->namespace = pp->pronamespace;
230 fip->rettype = pp->prorettype;
231 memcpy(fip->argtypes, pp->proargtypes.values, pp->pronargs * sizeof(Oid));
232 strlcpy(fip->fname, NameStr(pp->proname), NAMEDATALEN);
233
234 ReleaseSysCache(func_htp);
235
236 /*
237 * This must be last!
238 */
239 fip->funcid = func_id;
240}
241
242
243/*
244 * HandleFunctionRequest
245 *
246 * Server side of PQfn (fastpath function calls from the frontend).
247 * This corresponds to the libpq protocol symbol "F".
248 *
249 * INPUT:
250 * postgres.c has already read the message body and will pass it in
251 * msgBuf.
252 *
253 * Note: palloc()s done here and in the called function do not need to be
254 * cleaned up explicitly. We are called from PostgresMain() in the
255 * MessageContext memory context, which will be automatically reset when
256 * control returns to PostgresMain.
257 */
258void
259HandleFunctionRequest(StringInfo msgBuf)
260{
261 LOCAL_FCINFO(fcinfo, FUNC_MAX_ARGS);
262 Oid fid;
263 AclResult aclresult;
264 int16 rformat;
265 Datum retval;
266 struct fp_info my_fp;
267 struct fp_info *fip;
268 bool callit;
269 bool was_logged = false;
270 char msec_str[32];
271
272 /*
273 * We only accept COMMIT/ABORT if we are in an aborted transaction, and
274 * COMMIT/ABORT cannot be executed through the fastpath interface.
275 */
276 if (IsAbortedTransactionBlockState())
277 ereport(ERROR,
278 (errcode(ERRCODE_IN_FAILED_SQL_TRANSACTION),
279 errmsg("current transaction is aborted, "
280 "commands ignored until end of transaction block")));
281
282 /*
283 * Now that we know we are in a valid transaction, set snapshot in case
284 * needed by function itself or one of the datatype I/O routines.
285 */
286 PushActiveSnapshot(GetTransactionSnapshot());
287
288 /*
289 * Begin parsing the buffer contents.
290 */
291 if (PG_PROTOCOL_MAJOR(FrontendProtocol) < 3)
292 (void) pq_getmsgstring(msgBuf); /* dummy string */
293
294 fid = (Oid) pq_getmsgint(msgBuf, 4); /* function oid */
295
296 /*
297 * There used to be a lame attempt at caching lookup info here. Now we
298 * just do the lookups on every call.
299 */
300 fip = &my_fp;
301 fetch_fp_info(fid, fip);
302
303 /* Log as soon as we have the function OID and name */
304 if (log_statement == LOGSTMT_ALL)
305 {
306 ereport(LOG,
307 (errmsg("fastpath function call: \"%s\" (OID %u)",
308 fip->fname, fid)));
309 was_logged = true;
310 }
311
312 /*
313 * Check permission to access and call function. Since we didn't go
314 * through a normal name lookup, we need to check schema usage too.
315 */
316 aclresult = pg_namespace_aclcheck(fip->namespace, GetUserId(), ACL_USAGE);
317 if (aclresult != ACLCHECK_OK)
318 aclcheck_error(aclresult, OBJECT_SCHEMA,
319 get_namespace_name(fip->namespace));
320 InvokeNamespaceSearchHook(fip->namespace, true);
321
322 aclresult = pg_proc_aclcheck(fid, GetUserId(), ACL_EXECUTE);
323 if (aclresult != ACLCHECK_OK)
324 aclcheck_error(aclresult, OBJECT_FUNCTION,
325 get_func_name(fid));
326 InvokeFunctionExecuteHook(fid);
327
328 /*
329 * Prepare function call info block and insert arguments.
330 *
331 * Note: for now we pass collation = InvalidOid, so collation-sensitive
332 * functions can't be called this way. Perhaps we should pass
333 * DEFAULT_COLLATION_OID, instead?
334 */
335 InitFunctionCallInfoData(*fcinfo, &fip->flinfo, 0, InvalidOid, NULL, NULL);
336
337 if (PG_PROTOCOL_MAJOR(FrontendProtocol) >= 3)
338 rformat = parse_fcall_arguments(msgBuf, fip, fcinfo);
339 else
340 rformat = parse_fcall_arguments_20(msgBuf, fip, fcinfo);
341
342 /* Verify we reached the end of the message where expected. */
343 pq_getmsgend(msgBuf);
344
345 /*
346 * If func is strict, must not call it for null args.
347 */
348 callit = true;
349 if (fip->flinfo.fn_strict)
350 {
351 int i;
352
353 for (i = 0; i < fcinfo->nargs; i++)
354 {
355 if (fcinfo->args[i].isnull)
356 {
357 callit = false;
358 break;
359 }
360 }
361 }
362
363 if (callit)
364 {
365 /* Okay, do it ... */
366 retval = FunctionCallInvoke(fcinfo);
367 }
368 else
369 {
370 fcinfo->isnull = true;
371 retval = (Datum) 0;
372 }
373
374 /* ensure we do at least one CHECK_FOR_INTERRUPTS per function call */
375 CHECK_FOR_INTERRUPTS();
376
377 SendFunctionResult(retval, fcinfo->isnull, fip->rettype, rformat);
378
379 /* We no longer need the snapshot */
380 PopActiveSnapshot();
381
382 /*
383 * Emit duration logging if appropriate.
384 */
385 switch (check_log_duration(msec_str, was_logged))
386 {
387 case 1:
388 ereport(LOG,
389 (errmsg("duration: %s ms", msec_str)));
390 break;
391 case 2:
392 ereport(LOG,
393 (errmsg("duration: %s ms fastpath function call: \"%s\" (OID %u)",
394 msec_str, fip->fname, fid)));
395 break;
396 }
397}
398
399/*
400 * Parse function arguments in a 3.0 protocol message
401 *
402 * Argument values are loaded into *fcinfo, and the desired result format
403 * is returned.
404 */
405static int16
406parse_fcall_arguments(StringInfo msgBuf, struct fp_info *fip,
407 FunctionCallInfo fcinfo)
408{
409 int nargs;
410 int i;
411 int numAFormats;
412 int16 *aformats = NULL;
413 StringInfoData abuf;
414
415 /* Get the argument format codes */
416 numAFormats = pq_getmsgint(msgBuf, 2);
417 if (numAFormats > 0)
418 {
419 aformats = (int16 *) palloc(numAFormats * sizeof(int16));
420 for (i = 0; i < numAFormats; i++)
421 aformats[i] = pq_getmsgint(msgBuf, 2);
422 }
423
424 nargs = pq_getmsgint(msgBuf, 2); /* # of arguments */
425
426 if (fip->flinfo.fn_nargs != nargs || nargs > FUNC_MAX_ARGS)
427 ereport(ERROR,
428 (errcode(ERRCODE_PROTOCOL_VIOLATION),
429 errmsg("function call message contains %d arguments but function requires %d",
430 nargs, fip->flinfo.fn_nargs)));
431
432 fcinfo->nargs = nargs;
433
434 if (numAFormats > 1 && numAFormats != nargs)
435 ereport(ERROR,
436 (errcode(ERRCODE_PROTOCOL_VIOLATION),
437 errmsg("function call message contains %d argument formats but %d arguments",
438 numAFormats, nargs)));
439
440 initStringInfo(&abuf);
441
442 /*
443 * Copy supplied arguments into arg vector.
444 */
445 for (i = 0; i < nargs; ++i)
446 {
447 int argsize;
448 int16 aformat;
449
450 argsize = pq_getmsgint(msgBuf, 4);
451 if (argsize == -1)
452 {
453 fcinfo->args[i].isnull = true;
454 }
455 else
456 {
457 fcinfo->args[i].isnull = false;
458 if (argsize < 0)
459 ereport(ERROR,
460 (errcode(ERRCODE_PROTOCOL_VIOLATION),
461 errmsg("invalid argument size %d in function call message",
462 argsize)));
463
464 /* Reset abuf to empty, and insert raw data into it */
465 resetStringInfo(&abuf);
466 appendBinaryStringInfo(&abuf,
467 pq_getmsgbytes(msgBuf, argsize),
468 argsize);
469 }
470
471 if (numAFormats > 1)
472 aformat = aformats[i];
473 else if (numAFormats > 0)
474 aformat = aformats[0];
475 else
476 aformat = 0; /* default = text */
477
478 if (aformat == 0)
479 {
480 Oid typinput;
481 Oid typioparam;
482 char *pstring;
483
484 getTypeInputInfo(fip->argtypes[i], &typinput, &typioparam);
485
486 /*
487 * Since stringinfo.c keeps a trailing null in place even for
488 * binary data, the contents of abuf are a valid C string. We
489 * have to do encoding conversion before calling the typinput
490 * routine, though.
491 */
492 if (argsize == -1)
493 pstring = NULL;
494 else
495 pstring = pg_client_to_server(abuf.data, argsize);
496
497 fcinfo->args[i].value = OidInputFunctionCall(typinput, pstring,
498 typioparam, -1);
499 /* Free result of encoding conversion, if any */
500 if (pstring && pstring != abuf.data)
501 pfree(pstring);
502 }
503 else if (aformat == 1)
504 {
505 Oid typreceive;
506 Oid typioparam;
507 StringInfo bufptr;
508
509 /* Call the argument type's binary input converter */
510 getTypeBinaryInputInfo(fip->argtypes[i], &typreceive, &typioparam);
511
512 if (argsize == -1)
513 bufptr = NULL;
514 else
515 bufptr = &abuf;
516
517 fcinfo->args[i].value = OidReceiveFunctionCall(typreceive, bufptr,
518 typioparam, -1);
519
520 /* Trouble if it didn't eat the whole buffer */
521 if (argsize != -1 && abuf.cursor != abuf.len)
522 ereport(ERROR,
523 (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
524 errmsg("incorrect binary data format in function argument %d",
525 i + 1)));
526 }
527 else
528 ereport(ERROR,
529 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
530 errmsg("unsupported format code: %d", aformat)));
531 }
532
533 /* Return result format code */
534 return (int16) pq_getmsgint(msgBuf, 2);
535}
536
537/*
538 * Parse function arguments in a 2.0 protocol message
539 *
540 * Argument values are loaded into *fcinfo, and the desired result format
541 * is returned.
542 */
543static int16
544parse_fcall_arguments_20(StringInfo msgBuf, struct fp_info *fip,
545 FunctionCallInfo fcinfo)
546{
547 int nargs;
548 int i;
549 StringInfoData abuf;
550
551 nargs = pq_getmsgint(msgBuf, 4); /* # of arguments */
552
553 if (fip->flinfo.fn_nargs != nargs || nargs > FUNC_MAX_ARGS)
554 ereport(ERROR,
555 (errcode(ERRCODE_PROTOCOL_VIOLATION),
556 errmsg("function call message contains %d arguments but function requires %d",
557 nargs, fip->flinfo.fn_nargs)));
558
559 fcinfo->nargs = nargs;
560
561 initStringInfo(&abuf);
562
563 /*
564 * Copy supplied arguments into arg vector. In protocol 2.0 these are
565 * always assumed to be supplied in binary format.
566 *
567 * Note: although the original protocol 2.0 code did not have any way for
568 * the frontend to specify a NULL argument, we now choose to interpret
569 * length == -1 as meaning a NULL.
570 */
571 for (i = 0; i < nargs; ++i)
572 {
573 int argsize;
574 Oid typreceive;
575 Oid typioparam;
576
577 getTypeBinaryInputInfo(fip->argtypes[i], &typreceive, &typioparam);
578
579 argsize = pq_getmsgint(msgBuf, 4);
580 if (argsize == -1)
581 {
582 fcinfo->args[i].isnull = true;
583 fcinfo->args[i].value = OidReceiveFunctionCall(typreceive, NULL,
584 typioparam, -1);
585 continue;
586 }
587 fcinfo->args[i].isnull = false;
588 if (argsize < 0)
589 ereport(ERROR,
590 (errcode(ERRCODE_PROTOCOL_VIOLATION),
591 errmsg("invalid argument size %d in function call message",
592 argsize)));
593
594 /* Reset abuf to empty, and insert raw data into it */
595 resetStringInfo(&abuf);
596 appendBinaryStringInfo(&abuf,
597 pq_getmsgbytes(msgBuf, argsize),
598 argsize);
599
600 fcinfo->args[i].value = OidReceiveFunctionCall(typreceive, &abuf,
601 typioparam, -1);
602
603 /* Trouble if it didn't eat the whole buffer */
604 if (abuf.cursor != abuf.len)
605 ereport(ERROR,
606 (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
607 errmsg("incorrect binary data format in function argument %d",
608 i + 1)));
609 }
610
611 /* Desired result format is always binary in protocol 2.0 */
612 return 1;
613}
614