1 /*-------------------------------------------------------------------------
2 *
3 * fastpath.c
4 * routines to handle function requests from the frontend
5 *
6 * Portions Copyright (c) 1996-2021, 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
62 /* ----------------
63 * SendFunctionResult
64 * ----------------
65 */
66 static void
SendFunctionResult(Datum retval,bool isnull,Oid rettype,int16 format)67 SendFunctionResult(Datum retval, bool isnull, Oid rettype, int16 format)
68 {
69 StringInfoData buf;
70
71 pq_beginmessage(&buf, 'V');
72
73 if (isnull)
74 {
75 pq_sendint32(&buf, -1);
76 }
77 else
78 {
79 if (format == 0)
80 {
81 Oid typoutput;
82 bool typisvarlena;
83 char *outputstr;
84
85 getTypeOutputInfo(rettype, &typoutput, &typisvarlena);
86 outputstr = OidOutputFunctionCall(typoutput, retval);
87 pq_sendcountedtext(&buf, outputstr, strlen(outputstr), false);
88 pfree(outputstr);
89 }
90 else if (format == 1)
91 {
92 Oid typsend;
93 bool typisvarlena;
94 bytea *outputbytes;
95
96 getTypeBinaryOutputInfo(rettype, &typsend, &typisvarlena);
97 outputbytes = OidSendFunctionCall(typsend, retval);
98 pq_sendint32(&buf, VARSIZE(outputbytes) - VARHDRSZ);
99 pq_sendbytes(&buf, VARDATA(outputbytes),
100 VARSIZE(outputbytes) - VARHDRSZ);
101 pfree(outputbytes);
102 }
103 else
104 ereport(ERROR,
105 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
106 errmsg("unsupported format code: %d", format)));
107 }
108
109 pq_endmessage(&buf);
110 }
111
112 /*
113 * fetch_fp_info
114 *
115 * Performs catalog lookups to load a struct fp_info 'fip' for the
116 * function 'func_id'.
117 */
118 static void
fetch_fp_info(Oid func_id,struct fp_info * fip)119 fetch_fp_info(Oid func_id, struct fp_info *fip)
120 {
121 HeapTuple func_htp;
122 Form_pg_proc pp;
123
124 Assert(fip != NULL);
125
126 /*
127 * Since the validity of this structure is determined by whether the
128 * funcid is OK, we clear the funcid here. It must not be set to the
129 * correct value until we are about to return with a good struct fp_info,
130 * since we can be interrupted (i.e., with an ereport(ERROR, ...)) at any
131 * time. [No longer really an issue since we don't save the struct
132 * fp_info across transactions anymore, but keep it anyway.]
133 */
134 MemSet(fip, 0, sizeof(struct fp_info));
135 fip->funcid = InvalidOid;
136
137 func_htp = SearchSysCache1(PROCOID, ObjectIdGetDatum(func_id));
138 if (!HeapTupleIsValid(func_htp))
139 ereport(ERROR,
140 (errcode(ERRCODE_UNDEFINED_FUNCTION),
141 errmsg("function with OID %u does not exist", func_id)));
142 pp = (Form_pg_proc) GETSTRUCT(func_htp);
143
144 /* reject pg_proc entries that are unsafe to call via fastpath */
145 if (pp->prokind != PROKIND_FUNCTION || pp->proretset)
146 ereport(ERROR,
147 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
148 errmsg("cannot call function \"%s\" via fastpath interface",
149 NameStr(pp->proname))));
150
151 /* watch out for catalog entries with more than FUNC_MAX_ARGS args */
152 if (pp->pronargs > FUNC_MAX_ARGS)
153 elog(ERROR, "function %s has more than %d arguments",
154 NameStr(pp->proname), FUNC_MAX_ARGS);
155
156 fip->namespace = pp->pronamespace;
157 fip->rettype = pp->prorettype;
158 memcpy(fip->argtypes, pp->proargtypes.values, pp->pronargs * sizeof(Oid));
159 strlcpy(fip->fname, NameStr(pp->proname), NAMEDATALEN);
160
161 ReleaseSysCache(func_htp);
162
163 fmgr_info(func_id, &fip->flinfo);
164
165 /*
166 * This must be last!
167 */
168 fip->funcid = func_id;
169 }
170
171
172 /*
173 * HandleFunctionRequest
174 *
175 * Server side of PQfn (fastpath function calls from the frontend).
176 * This corresponds to the libpq protocol symbol "F".
177 *
178 * INPUT:
179 * postgres.c has already read the message body and will pass it in
180 * msgBuf.
181 *
182 * Note: palloc()s done here and in the called function do not need to be
183 * cleaned up explicitly. We are called from PostgresMain() in the
184 * MessageContext memory context, which will be automatically reset when
185 * control returns to PostgresMain.
186 */
187 void
HandleFunctionRequest(StringInfo msgBuf)188 HandleFunctionRequest(StringInfo msgBuf)
189 {
190 LOCAL_FCINFO(fcinfo, FUNC_MAX_ARGS);
191 Oid fid;
192 AclResult aclresult;
193 int16 rformat;
194 Datum retval;
195 struct fp_info my_fp;
196 struct fp_info *fip;
197 bool callit;
198 bool was_logged = false;
199 char msec_str[32];
200
201 /*
202 * We only accept COMMIT/ABORT if we are in an aborted transaction, and
203 * COMMIT/ABORT cannot be executed through the fastpath interface.
204 */
205 if (IsAbortedTransactionBlockState())
206 ereport(ERROR,
207 (errcode(ERRCODE_IN_FAILED_SQL_TRANSACTION),
208 errmsg("current transaction is aborted, "
209 "commands ignored until end of transaction block")));
210
211 /*
212 * Now that we know we are in a valid transaction, set snapshot in case
213 * needed by function itself or one of the datatype I/O routines.
214 */
215 PushActiveSnapshot(GetTransactionSnapshot());
216
217 /*
218 * Begin parsing the buffer contents.
219 */
220 fid = (Oid) pq_getmsgint(msgBuf, 4); /* function oid */
221
222 /*
223 * There used to be a lame attempt at caching lookup info here. Now we
224 * just do the lookups on every call.
225 */
226 fip = &my_fp;
227 fetch_fp_info(fid, fip);
228
229 /* Log as soon as we have the function OID and name */
230 if (log_statement == LOGSTMT_ALL)
231 {
232 ereport(LOG,
233 (errmsg("fastpath function call: \"%s\" (OID %u)",
234 fip->fname, fid)));
235 was_logged = true;
236 }
237
238 /*
239 * Check permission to access and call function. Since we didn't go
240 * through a normal name lookup, we need to check schema usage too.
241 */
242 aclresult = pg_namespace_aclcheck(fip->namespace, GetUserId(), ACL_USAGE);
243 if (aclresult != ACLCHECK_OK)
244 aclcheck_error(aclresult, OBJECT_SCHEMA,
245 get_namespace_name(fip->namespace));
246 InvokeNamespaceSearchHook(fip->namespace, true);
247
248 aclresult = pg_proc_aclcheck(fid, GetUserId(), ACL_EXECUTE);
249 if (aclresult != ACLCHECK_OK)
250 aclcheck_error(aclresult, OBJECT_FUNCTION,
251 get_func_name(fid));
252 InvokeFunctionExecuteHook(fid);
253
254 /*
255 * Prepare function call info block and insert arguments.
256 *
257 * Note: for now we pass collation = InvalidOid, so collation-sensitive
258 * functions can't be called this way. Perhaps we should pass
259 * DEFAULT_COLLATION_OID, instead?
260 */
261 InitFunctionCallInfoData(*fcinfo, &fip->flinfo, 0, InvalidOid, NULL, NULL);
262
263 rformat = parse_fcall_arguments(msgBuf, fip, fcinfo);
264
265 /* Verify we reached the end of the message where expected. */
266 pq_getmsgend(msgBuf);
267
268 /*
269 * If func is strict, must not call it for null args.
270 */
271 callit = true;
272 if (fip->flinfo.fn_strict)
273 {
274 int i;
275
276 for (i = 0; i < fcinfo->nargs; i++)
277 {
278 if (fcinfo->args[i].isnull)
279 {
280 callit = false;
281 break;
282 }
283 }
284 }
285
286 if (callit)
287 {
288 /* Okay, do it ... */
289 retval = FunctionCallInvoke(fcinfo);
290 }
291 else
292 {
293 fcinfo->isnull = true;
294 retval = (Datum) 0;
295 }
296
297 /* ensure we do at least one CHECK_FOR_INTERRUPTS per function call */
298 CHECK_FOR_INTERRUPTS();
299
300 SendFunctionResult(retval, fcinfo->isnull, fip->rettype, rformat);
301
302 /* We no longer need the snapshot */
303 PopActiveSnapshot();
304
305 /*
306 * Emit duration logging if appropriate.
307 */
308 switch (check_log_duration(msec_str, was_logged))
309 {
310 case 1:
311 ereport(LOG,
312 (errmsg("duration: %s ms", msec_str)));
313 break;
314 case 2:
315 ereport(LOG,
316 (errmsg("duration: %s ms fastpath function call: \"%s\" (OID %u)",
317 msec_str, fip->fname, fid)));
318 break;
319 }
320 }
321
322 /*
323 * Parse function arguments in a 3.0 protocol message
324 *
325 * Argument values are loaded into *fcinfo, and the desired result format
326 * is returned.
327 */
328 static int16
parse_fcall_arguments(StringInfo msgBuf,struct fp_info * fip,FunctionCallInfo fcinfo)329 parse_fcall_arguments(StringInfo msgBuf, struct fp_info *fip,
330 FunctionCallInfo fcinfo)
331 {
332 int nargs;
333 int i;
334 int numAFormats;
335 int16 *aformats = NULL;
336 StringInfoData abuf;
337
338 /* Get the argument format codes */
339 numAFormats = pq_getmsgint(msgBuf, 2);
340 if (numAFormats > 0)
341 {
342 aformats = (int16 *) palloc(numAFormats * sizeof(int16));
343 for (i = 0; i < numAFormats; i++)
344 aformats[i] = pq_getmsgint(msgBuf, 2);
345 }
346
347 nargs = pq_getmsgint(msgBuf, 2); /* # of arguments */
348
349 if (fip->flinfo.fn_nargs != nargs || nargs > FUNC_MAX_ARGS)
350 ereport(ERROR,
351 (errcode(ERRCODE_PROTOCOL_VIOLATION),
352 errmsg("function call message contains %d arguments but function requires %d",
353 nargs, fip->flinfo.fn_nargs)));
354
355 fcinfo->nargs = nargs;
356
357 if (numAFormats > 1 && numAFormats != nargs)
358 ereport(ERROR,
359 (errcode(ERRCODE_PROTOCOL_VIOLATION),
360 errmsg("function call message contains %d argument formats but %d arguments",
361 numAFormats, nargs)));
362
363 initStringInfo(&abuf);
364
365 /*
366 * Copy supplied arguments into arg vector.
367 */
368 for (i = 0; i < nargs; ++i)
369 {
370 int argsize;
371 int16 aformat;
372
373 argsize = pq_getmsgint(msgBuf, 4);
374 if (argsize == -1)
375 {
376 fcinfo->args[i].isnull = true;
377 }
378 else
379 {
380 fcinfo->args[i].isnull = false;
381 if (argsize < 0)
382 ereport(ERROR,
383 (errcode(ERRCODE_PROTOCOL_VIOLATION),
384 errmsg("invalid argument size %d in function call message",
385 argsize)));
386
387 /* Reset abuf to empty, and insert raw data into it */
388 resetStringInfo(&abuf);
389 appendBinaryStringInfo(&abuf,
390 pq_getmsgbytes(msgBuf, argsize),
391 argsize);
392 }
393
394 if (numAFormats > 1)
395 aformat = aformats[i];
396 else if (numAFormats > 0)
397 aformat = aformats[0];
398 else
399 aformat = 0; /* default = text */
400
401 if (aformat == 0)
402 {
403 Oid typinput;
404 Oid typioparam;
405 char *pstring;
406
407 getTypeInputInfo(fip->argtypes[i], &typinput, &typioparam);
408
409 /*
410 * Since stringinfo.c keeps a trailing null in place even for
411 * binary data, the contents of abuf are a valid C string. We
412 * have to do encoding conversion before calling the typinput
413 * routine, though.
414 */
415 if (argsize == -1)
416 pstring = NULL;
417 else
418 pstring = pg_client_to_server(abuf.data, argsize);
419
420 fcinfo->args[i].value = OidInputFunctionCall(typinput, pstring,
421 typioparam, -1);
422 /* Free result of encoding conversion, if any */
423 if (pstring && pstring != abuf.data)
424 pfree(pstring);
425 }
426 else if (aformat == 1)
427 {
428 Oid typreceive;
429 Oid typioparam;
430 StringInfo bufptr;
431
432 /* Call the argument type's binary input converter */
433 getTypeBinaryInputInfo(fip->argtypes[i], &typreceive, &typioparam);
434
435 if (argsize == -1)
436 bufptr = NULL;
437 else
438 bufptr = &abuf;
439
440 fcinfo->args[i].value = OidReceiveFunctionCall(typreceive, bufptr,
441 typioparam, -1);
442
443 /* Trouble if it didn't eat the whole buffer */
444 if (argsize != -1 && abuf.cursor != abuf.len)
445 ereport(ERROR,
446 (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
447 errmsg("incorrect binary data format in function argument %d",
448 i + 1)));
449 }
450 else
451 ereport(ERROR,
452 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
453 errmsg("unsupported format code: %d", aformat)));
454 }
455
456 /* Return result format code */
457 return (int16) pq_getmsgint(msgBuf, 2);
458 }
459