1 /*-------------------------------------------------------------------------
2 *
3 * fe-protocol3.c
4 * functions that are specific to frontend/backend protocol version 3
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/interfaces/libpq/fe-protocol3.c
12 *
13 *-------------------------------------------------------------------------
14 */
15 #include "postgres_fe.h"
16
17 #include <ctype.h>
18 #include <fcntl.h>
19
20 #include "libpq-fe.h"
21 #include "libpq-int.h"
22
23 #include "mb/pg_wchar.h"
24 #include "port/pg_bswap.h"
25
26 #ifdef WIN32
27 #include "win32.h"
28 #else
29 #include <unistd.h>
30 #ifdef HAVE_NETINET_TCP_H
31 #include <netinet/tcp.h>
32 #endif
33 #endif
34
35
36 /*
37 * This macro lists the backend message types that could be "long" (more
38 * than a couple of kilobytes).
39 */
40 #define VALID_LONG_MESSAGE_TYPE(id) \
41 ((id) == 'T' || (id) == 'D' || (id) == 'd' || (id) == 'V' || \
42 (id) == 'E' || (id) == 'N' || (id) == 'A')
43
44 #define PQmblenBounded(s, e) strnlen(s, PQmblen(s, e))
45
46
47 static void handleSyncLoss(PGconn *conn, char id, int msgLength);
48 static int getRowDescriptions(PGconn *conn, int msgLength);
49 static int getParamDescriptions(PGconn *conn, int msgLength);
50 static int getAnotherTuple(PGconn *conn, int msgLength);
51 static int getParameterStatus(PGconn *conn);
52 static int getNotify(PGconn *conn);
53 static int getCopyStart(PGconn *conn, ExecStatusType copytype);
54 static int getReadyForQuery(PGconn *conn);
55 static void reportErrorPosition(PQExpBuffer msg, const char *query,
56 int loc, int encoding);
57 static int build_startup_packet(const PGconn *conn, char *packet,
58 const PQEnvironmentOption *options);
59
60
61 /*
62 * parseInput: if appropriate, parse input data from backend
63 * until input is exhausted or a stopping state is reached.
64 * Note that this function will NOT attempt to read more data from the backend.
65 */
66 void
pqParseInput3(PGconn * conn)67 pqParseInput3(PGconn *conn)
68 {
69 char id;
70 int msgLength;
71 int avail;
72
73 /*
74 * Loop to parse successive complete messages available in the buffer.
75 */
76 for (;;)
77 {
78 /*
79 * Try to read a message. First get the type code and length. Return
80 * if not enough data.
81 */
82 conn->inCursor = conn->inStart;
83 if (pqGetc(&id, conn))
84 return;
85 if (pqGetInt(&msgLength, 4, conn))
86 return;
87
88 /*
89 * Try to validate message type/length here. A length less than 4 is
90 * definitely broken. Large lengths should only be believed for a few
91 * message types.
92 */
93 if (msgLength < 4)
94 {
95 handleSyncLoss(conn, id, msgLength);
96 return;
97 }
98 if (msgLength > 30000 && !VALID_LONG_MESSAGE_TYPE(id))
99 {
100 handleSyncLoss(conn, id, msgLength);
101 return;
102 }
103
104 /*
105 * Can't process if message body isn't all here yet.
106 */
107 msgLength -= 4;
108 avail = conn->inEnd - conn->inCursor;
109 if (avail < msgLength)
110 {
111 /*
112 * Before returning, enlarge the input buffer if needed to hold
113 * the whole message. This is better than leaving it to
114 * pqReadData because we can avoid multiple cycles of realloc()
115 * when the message is large; also, we can implement a reasonable
116 * recovery strategy if we are unable to make the buffer big
117 * enough.
118 */
119 if (pqCheckInBufferSpace(conn->inCursor + (size_t) msgLength,
120 conn))
121 {
122 /*
123 * XXX add some better recovery code... plan is to skip over
124 * the message using its length, then report an error. For the
125 * moment, just treat this like loss of sync (which indeed it
126 * might be!)
127 */
128 handleSyncLoss(conn, id, msgLength);
129 }
130 return;
131 }
132
133 /*
134 * NOTIFY and NOTICE messages can happen in any state; always process
135 * them right away.
136 *
137 * Most other messages should only be processed while in BUSY state.
138 * (In particular, in READY state we hold off further parsing until
139 * the application collects the current PGresult.)
140 *
141 * However, if the state is IDLE then we got trouble; we need to deal
142 * with the unexpected message somehow.
143 *
144 * ParameterStatus ('S') messages are a special case: in IDLE state we
145 * must process 'em (this case could happen if a new value was adopted
146 * from config file due to SIGHUP), but otherwise we hold off until
147 * BUSY state.
148 */
149 if (id == 'A')
150 {
151 if (getNotify(conn))
152 return;
153 }
154 else if (id == 'N')
155 {
156 if (pqGetErrorNotice3(conn, false))
157 return;
158 }
159 else if (conn->asyncStatus != PGASYNC_BUSY)
160 {
161 /* If not IDLE state, just wait ... */
162 if (conn->asyncStatus != PGASYNC_IDLE)
163 return;
164
165 /*
166 * Unexpected message in IDLE state; need to recover somehow.
167 * ERROR messages are handled using the notice processor;
168 * ParameterStatus is handled normally; anything else is just
169 * dropped on the floor after displaying a suitable warning
170 * notice. (An ERROR is very possibly the backend telling us why
171 * it is about to close the connection, so we don't want to just
172 * discard it...)
173 */
174 if (id == 'E')
175 {
176 if (pqGetErrorNotice3(conn, false /* treat as notice */ ))
177 return;
178 }
179 else if (id == 'S')
180 {
181 if (getParameterStatus(conn))
182 return;
183 }
184 else
185 {
186 pqInternalNotice(&conn->noticeHooks,
187 "message type 0x%02x arrived from server while idle",
188 id);
189 /* Discard the unexpected message */
190 conn->inCursor += msgLength;
191 }
192 }
193 else
194 {
195 /*
196 * In BUSY state, we can process everything.
197 */
198 switch (id)
199 {
200 case 'C': /* command complete */
201 if (pqGets(&conn->workBuffer, conn))
202 return;
203 if (conn->result == NULL)
204 {
205 conn->result = PQmakeEmptyPGresult(conn,
206 PGRES_COMMAND_OK);
207 if (!conn->result)
208 {
209 printfPQExpBuffer(&conn->errorMessage,
210 libpq_gettext("out of memory"));
211 pqSaveErrorResult(conn);
212 }
213 }
214 if (conn->result)
215 strlcpy(conn->result->cmdStatus, conn->workBuffer.data,
216 CMDSTATUS_LEN);
217 conn->asyncStatus = PGASYNC_READY;
218 break;
219 case 'E': /* error return */
220 if (pqGetErrorNotice3(conn, true))
221 return;
222 conn->asyncStatus = PGASYNC_READY;
223 break;
224 case 'Z': /* backend is ready for new query */
225 if (getReadyForQuery(conn))
226 return;
227 conn->asyncStatus = PGASYNC_IDLE;
228 break;
229 case 'I': /* empty query */
230 if (conn->result == NULL)
231 {
232 conn->result = PQmakeEmptyPGresult(conn,
233 PGRES_EMPTY_QUERY);
234 if (!conn->result)
235 {
236 printfPQExpBuffer(&conn->errorMessage,
237 libpq_gettext("out of memory"));
238 pqSaveErrorResult(conn);
239 }
240 }
241 conn->asyncStatus = PGASYNC_READY;
242 break;
243 case '1': /* Parse Complete */
244 /* If we're doing PQprepare, we're done; else ignore */
245 if (conn->queryclass == PGQUERY_PREPARE)
246 {
247 if (conn->result == NULL)
248 {
249 conn->result = PQmakeEmptyPGresult(conn,
250 PGRES_COMMAND_OK);
251 if (!conn->result)
252 {
253 printfPQExpBuffer(&conn->errorMessage,
254 libpq_gettext("out of memory"));
255 pqSaveErrorResult(conn);
256 }
257 }
258 conn->asyncStatus = PGASYNC_READY;
259 }
260 break;
261 case '2': /* Bind Complete */
262 case '3': /* Close Complete */
263 /* Nothing to do for these message types */
264 break;
265 case 'S': /* parameter status */
266 if (getParameterStatus(conn))
267 return;
268 break;
269 case 'K': /* secret key data from the backend */
270
271 /*
272 * This is expected only during backend startup, but it's
273 * just as easy to handle it as part of the main loop.
274 * Save the data and continue processing.
275 */
276 if (pqGetInt(&(conn->be_pid), 4, conn))
277 return;
278 if (pqGetInt(&(conn->be_key), 4, conn))
279 return;
280 break;
281 case 'T': /* Row Description */
282 if (conn->result != NULL &&
283 conn->result->resultStatus == PGRES_FATAL_ERROR)
284 {
285 /*
286 * We've already choked for some reason. Just discard
287 * the data till we get to the end of the query.
288 */
289 conn->inCursor += msgLength;
290 }
291 else if (conn->result == NULL ||
292 conn->queryclass == PGQUERY_DESCRIBE)
293 {
294 /* First 'T' in a query sequence */
295 if (getRowDescriptions(conn, msgLength))
296 return;
297 }
298 else
299 {
300 /*
301 * A new 'T' message is treated as the start of
302 * another PGresult. (It is not clear that this is
303 * really possible with the current backend.) We stop
304 * parsing until the application accepts the current
305 * result.
306 */
307 conn->asyncStatus = PGASYNC_READY;
308 return;
309 }
310 break;
311 case 'n': /* No Data */
312
313 /*
314 * NoData indicates that we will not be seeing a
315 * RowDescription message because the statement or portal
316 * inquired about doesn't return rows.
317 *
318 * If we're doing a Describe, we have to pass something
319 * back to the client, so set up a COMMAND_OK result,
320 * instead of TUPLES_OK. Otherwise we can just ignore
321 * this message.
322 */
323 if (conn->queryclass == PGQUERY_DESCRIBE)
324 {
325 if (conn->result == NULL)
326 {
327 conn->result = PQmakeEmptyPGresult(conn,
328 PGRES_COMMAND_OK);
329 if (!conn->result)
330 {
331 printfPQExpBuffer(&conn->errorMessage,
332 libpq_gettext("out of memory"));
333 pqSaveErrorResult(conn);
334 }
335 }
336 conn->asyncStatus = PGASYNC_READY;
337 }
338 break;
339 case 't': /* Parameter Description */
340 if (getParamDescriptions(conn, msgLength))
341 return;
342 break;
343 case 'D': /* Data Row */
344 if (conn->result != NULL &&
345 conn->result->resultStatus == PGRES_TUPLES_OK)
346 {
347 /* Read another tuple of a normal query response */
348 if (getAnotherTuple(conn, msgLength))
349 return;
350 }
351 else if (conn->result != NULL &&
352 conn->result->resultStatus == PGRES_FATAL_ERROR)
353 {
354 /*
355 * We've already choked for some reason. Just discard
356 * tuples till we get to the end of the query.
357 */
358 conn->inCursor += msgLength;
359 }
360 else
361 {
362 /* Set up to report error at end of query */
363 printfPQExpBuffer(&conn->errorMessage,
364 libpq_gettext("server sent data (\"D\" message) without prior row description (\"T\" message)\n"));
365 pqSaveErrorResult(conn);
366 /* Discard the unexpected message */
367 conn->inCursor += msgLength;
368 }
369 break;
370 case 'G': /* Start Copy In */
371 if (getCopyStart(conn, PGRES_COPY_IN))
372 return;
373 conn->asyncStatus = PGASYNC_COPY_IN;
374 break;
375 case 'H': /* Start Copy Out */
376 if (getCopyStart(conn, PGRES_COPY_OUT))
377 return;
378 conn->asyncStatus = PGASYNC_COPY_OUT;
379 conn->copy_already_done = 0;
380 break;
381 case 'W': /* Start Copy Both */
382 if (getCopyStart(conn, PGRES_COPY_BOTH))
383 return;
384 conn->asyncStatus = PGASYNC_COPY_BOTH;
385 conn->copy_already_done = 0;
386 break;
387 case 'd': /* Copy Data */
388
389 /*
390 * If we see Copy Data, just silently drop it. This would
391 * only occur if application exits COPY OUT mode too
392 * early.
393 */
394 conn->inCursor += msgLength;
395 break;
396 case 'c': /* Copy Done */
397
398 /*
399 * If we see Copy Done, just silently drop it. This is
400 * the normal case during PQendcopy. We will keep
401 * swallowing data, expecting to see command-complete for
402 * the COPY command.
403 */
404 break;
405 default:
406 printfPQExpBuffer(&conn->errorMessage,
407 libpq_gettext(
408 "unexpected response from server; first received character was \"%c\"\n"),
409 id);
410 /* build an error result holding the error message */
411 pqSaveErrorResult(conn);
412 /* not sure if we will see more, so go to ready state */
413 conn->asyncStatus = PGASYNC_READY;
414 /* Discard the unexpected message */
415 conn->inCursor += msgLength;
416 break;
417 } /* switch on protocol character */
418 }
419 /* Successfully consumed this message */
420 if (conn->inCursor == conn->inStart + 5 + msgLength)
421 {
422 /* Normal case: parsing agrees with specified length */
423 conn->inStart = conn->inCursor;
424 }
425 else
426 {
427 /* Trouble --- report it */
428 printfPQExpBuffer(&conn->errorMessage,
429 libpq_gettext("message contents do not agree with length in message type \"%c\"\n"),
430 id);
431 /* build an error result holding the error message */
432 pqSaveErrorResult(conn);
433 conn->asyncStatus = PGASYNC_READY;
434 /* trust the specified message length as what to skip */
435 conn->inStart += 5 + msgLength;
436 }
437 }
438 }
439
440 /*
441 * handleSyncLoss: clean up after loss of message-boundary sync
442 *
443 * There isn't really a lot we can do here except abandon the connection.
444 */
445 static void
handleSyncLoss(PGconn * conn,char id,int msgLength)446 handleSyncLoss(PGconn *conn, char id, int msgLength)
447 {
448 printfPQExpBuffer(&conn->errorMessage,
449 libpq_gettext(
450 "lost synchronization with server: got message type \"%c\", length %d\n"),
451 id, msgLength);
452 /* build an error result holding the error message */
453 pqSaveErrorResult(conn);
454 conn->asyncStatus = PGASYNC_READY; /* drop out of GetResult wait loop */
455 /* flush input data since we're giving up on processing it */
456 pqDropConnection(conn, true);
457 conn->status = CONNECTION_BAD; /* No more connection to backend */
458 }
459
460 /*
461 * parseInput subroutine to read a 'T' (row descriptions) message.
462 * We'll build a new PGresult structure (unless called for a Describe
463 * command for a prepared statement) containing the attribute data.
464 * Returns: 0 if processed message successfully, EOF to suspend parsing
465 * (the latter case is not actually used currently).
466 */
467 static int
getRowDescriptions(PGconn * conn,int msgLength)468 getRowDescriptions(PGconn *conn, int msgLength)
469 {
470 PGresult *result;
471 int nfields;
472 const char *errmsg;
473 int i;
474
475 /*
476 * When doing Describe for a prepared statement, there'll already be a
477 * PGresult created by getParamDescriptions, and we should fill data into
478 * that. Otherwise, create a new, empty PGresult.
479 */
480 if (conn->queryclass == PGQUERY_DESCRIBE)
481 {
482 if (conn->result)
483 result = conn->result;
484 else
485 result = PQmakeEmptyPGresult(conn, PGRES_COMMAND_OK);
486 }
487 else
488 result = PQmakeEmptyPGresult(conn, PGRES_TUPLES_OK);
489 if (!result)
490 {
491 errmsg = NULL; /* means "out of memory", see below */
492 goto advance_and_error;
493 }
494
495 /* parseInput already read the 'T' label and message length. */
496 /* the next two bytes are the number of fields */
497 if (pqGetInt(&(result->numAttributes), 2, conn))
498 {
499 /* We should not run out of data here, so complain */
500 errmsg = libpq_gettext("insufficient data in \"T\" message");
501 goto advance_and_error;
502 }
503 nfields = result->numAttributes;
504
505 /* allocate space for the attribute descriptors */
506 if (nfields > 0)
507 {
508 result->attDescs = (PGresAttDesc *)
509 pqResultAlloc(result, nfields * sizeof(PGresAttDesc), true);
510 if (!result->attDescs)
511 {
512 errmsg = NULL; /* means "out of memory", see below */
513 goto advance_and_error;
514 }
515 MemSet(result->attDescs, 0, nfields * sizeof(PGresAttDesc));
516 }
517
518 /* result->binary is true only if ALL columns are binary */
519 result->binary = (nfields > 0) ? 1 : 0;
520
521 /* get type info */
522 for (i = 0; i < nfields; i++)
523 {
524 int tableid;
525 int columnid;
526 int typid;
527 int typlen;
528 int atttypmod;
529 int format;
530
531 if (pqGets(&conn->workBuffer, conn) ||
532 pqGetInt(&tableid, 4, conn) ||
533 pqGetInt(&columnid, 2, conn) ||
534 pqGetInt(&typid, 4, conn) ||
535 pqGetInt(&typlen, 2, conn) ||
536 pqGetInt(&atttypmod, 4, conn) ||
537 pqGetInt(&format, 2, conn))
538 {
539 /* We should not run out of data here, so complain */
540 errmsg = libpq_gettext("insufficient data in \"T\" message");
541 goto advance_and_error;
542 }
543
544 /*
545 * Since pqGetInt treats 2-byte integers as unsigned, we need to
546 * coerce these results to signed form.
547 */
548 columnid = (int) ((int16) columnid);
549 typlen = (int) ((int16) typlen);
550 format = (int) ((int16) format);
551
552 result->attDescs[i].name = pqResultStrdup(result,
553 conn->workBuffer.data);
554 if (!result->attDescs[i].name)
555 {
556 errmsg = NULL; /* means "out of memory", see below */
557 goto advance_and_error;
558 }
559 result->attDescs[i].tableid = tableid;
560 result->attDescs[i].columnid = columnid;
561 result->attDescs[i].format = format;
562 result->attDescs[i].typid = typid;
563 result->attDescs[i].typlen = typlen;
564 result->attDescs[i].atttypmod = atttypmod;
565
566 if (format != 1)
567 result->binary = 0;
568 }
569
570 /* Success! */
571 conn->result = result;
572
573 /*
574 * If we're doing a Describe, we're done, and ready to pass the result
575 * back to the client.
576 */
577 if (conn->queryclass == PGQUERY_DESCRIBE)
578 {
579 conn->asyncStatus = PGASYNC_READY;
580 return 0;
581 }
582
583 /*
584 * We could perform additional setup for the new result set here, but for
585 * now there's nothing else to do.
586 */
587
588 /* And we're done. */
589 return 0;
590
591 advance_and_error:
592 /* Discard unsaved result, if any */
593 if (result && result != conn->result)
594 PQclear(result);
595
596 /*
597 * Replace partially constructed result with an error result. First
598 * discard the old result to try to win back some memory.
599 */
600 pqClearAsyncResult(conn);
601
602 /*
603 * If preceding code didn't provide an error message, assume "out of
604 * memory" was meant. The advantage of having this special case is that
605 * freeing the old result first greatly improves the odds that gettext()
606 * will succeed in providing a translation.
607 */
608 if (!errmsg)
609 errmsg = libpq_gettext("out of memory for query result");
610
611 printfPQExpBuffer(&conn->errorMessage, "%s\n", errmsg);
612 pqSaveErrorResult(conn);
613
614 /*
615 * Show the message as fully consumed, else pqParseInput3 will overwrite
616 * our error with a complaint about that.
617 */
618 conn->inCursor = conn->inStart + 5 + msgLength;
619
620 /*
621 * Return zero to allow input parsing to continue. Subsequent "D"
622 * messages will be ignored until we get to end of data, since an error
623 * result is already set up.
624 */
625 return 0;
626 }
627
628 /*
629 * parseInput subroutine to read a 't' (ParameterDescription) message.
630 * We'll build a new PGresult structure containing the parameter data.
631 * Returns: 0 if processed message successfully, EOF to suspend parsing
632 * (the latter case is not actually used currently).
633 */
634 static int
getParamDescriptions(PGconn * conn,int msgLength)635 getParamDescriptions(PGconn *conn, int msgLength)
636 {
637 PGresult *result;
638 const char *errmsg = NULL; /* means "out of memory", see below */
639 int nparams;
640 int i;
641
642 result = PQmakeEmptyPGresult(conn, PGRES_COMMAND_OK);
643 if (!result)
644 goto advance_and_error;
645
646 /* parseInput already read the 't' label and message length. */
647 /* the next two bytes are the number of parameters */
648 if (pqGetInt(&(result->numParameters), 2, conn))
649 goto not_enough_data;
650 nparams = result->numParameters;
651
652 /* allocate space for the parameter descriptors */
653 if (nparams > 0)
654 {
655 result->paramDescs = (PGresParamDesc *)
656 pqResultAlloc(result, nparams * sizeof(PGresParamDesc), true);
657 if (!result->paramDescs)
658 goto advance_and_error;
659 MemSet(result->paramDescs, 0, nparams * sizeof(PGresParamDesc));
660 }
661
662 /* get parameter info */
663 for (i = 0; i < nparams; i++)
664 {
665 int typid;
666
667 if (pqGetInt(&typid, 4, conn))
668 goto not_enough_data;
669 result->paramDescs[i].typid = typid;
670 }
671
672 /* Success! */
673 conn->result = result;
674
675 return 0;
676
677 not_enough_data:
678 errmsg = libpq_gettext("insufficient data in \"t\" message");
679
680 advance_and_error:
681 /* Discard unsaved result, if any */
682 if (result && result != conn->result)
683 PQclear(result);
684
685 /*
686 * Replace partially constructed result with an error result. First
687 * discard the old result to try to win back some memory.
688 */
689 pqClearAsyncResult(conn);
690
691 /*
692 * If preceding code didn't provide an error message, assume "out of
693 * memory" was meant. The advantage of having this special case is that
694 * freeing the old result first greatly improves the odds that gettext()
695 * will succeed in providing a translation.
696 */
697 if (!errmsg)
698 errmsg = libpq_gettext("out of memory");
699 printfPQExpBuffer(&conn->errorMessage, "%s\n", errmsg);
700 pqSaveErrorResult(conn);
701
702 /*
703 * Show the message as fully consumed, else pqParseInput3 will overwrite
704 * our error with a complaint about that.
705 */
706 conn->inCursor = conn->inStart + 5 + msgLength;
707
708 /*
709 * Return zero to allow input parsing to continue. Essentially, we've
710 * replaced the COMMAND_OK result with an error result, but since this
711 * doesn't affect the protocol state, it's fine.
712 */
713 return 0;
714 }
715
716 /*
717 * parseInput subroutine to read a 'D' (row data) message.
718 * We fill rowbuf with column pointers and then call the row processor.
719 * Returns: 0 if processed message successfully, EOF to suspend parsing
720 * (the latter case is not actually used currently).
721 */
722 static int
getAnotherTuple(PGconn * conn,int msgLength)723 getAnotherTuple(PGconn *conn, int msgLength)
724 {
725 PGresult *result = conn->result;
726 int nfields = result->numAttributes;
727 const char *errmsg;
728 PGdataValue *rowbuf;
729 int tupnfields; /* # fields from tuple */
730 int vlen; /* length of the current field value */
731 int i;
732
733 /* Get the field count and make sure it's what we expect */
734 if (pqGetInt(&tupnfields, 2, conn))
735 {
736 /* We should not run out of data here, so complain */
737 errmsg = libpq_gettext("insufficient data in \"D\" message");
738 goto advance_and_error;
739 }
740
741 if (tupnfields != nfields)
742 {
743 errmsg = libpq_gettext("unexpected field count in \"D\" message");
744 goto advance_and_error;
745 }
746
747 /* Resize row buffer if needed */
748 rowbuf = conn->rowBuf;
749 if (nfields > conn->rowBufLen)
750 {
751 rowbuf = (PGdataValue *) realloc(rowbuf,
752 nfields * sizeof(PGdataValue));
753 if (!rowbuf)
754 {
755 errmsg = NULL; /* means "out of memory", see below */
756 goto advance_and_error;
757 }
758 conn->rowBuf = rowbuf;
759 conn->rowBufLen = nfields;
760 }
761
762 /* Scan the fields */
763 for (i = 0; i < nfields; i++)
764 {
765 /* get the value length */
766 if (pqGetInt(&vlen, 4, conn))
767 {
768 /* We should not run out of data here, so complain */
769 errmsg = libpq_gettext("insufficient data in \"D\" message");
770 goto advance_and_error;
771 }
772 rowbuf[i].len = vlen;
773
774 /*
775 * rowbuf[i].value always points to the next address in the data
776 * buffer even if the value is NULL. This allows row processors to
777 * estimate data sizes more easily.
778 */
779 rowbuf[i].value = conn->inBuffer + conn->inCursor;
780
781 /* Skip over the data value */
782 if (vlen > 0)
783 {
784 if (pqSkipnchar(vlen, conn))
785 {
786 /* We should not run out of data here, so complain */
787 errmsg = libpq_gettext("insufficient data in \"D\" message");
788 goto advance_and_error;
789 }
790 }
791 }
792
793 /* Process the collected row */
794 errmsg = NULL;
795 if (pqRowProcessor(conn, &errmsg))
796 return 0; /* normal, successful exit */
797
798 /* pqRowProcessor failed, fall through to report it */
799
800 advance_and_error:
801
802 /*
803 * Replace partially constructed result with an error result. First
804 * discard the old result to try to win back some memory.
805 */
806 pqClearAsyncResult(conn);
807
808 /*
809 * If preceding code didn't provide an error message, assume "out of
810 * memory" was meant. The advantage of having this special case is that
811 * freeing the old result first greatly improves the odds that gettext()
812 * will succeed in providing a translation.
813 */
814 if (!errmsg)
815 errmsg = libpq_gettext("out of memory for query result");
816
817 printfPQExpBuffer(&conn->errorMessage, "%s\n", errmsg);
818 pqSaveErrorResult(conn);
819
820 /*
821 * Show the message as fully consumed, else pqParseInput3 will overwrite
822 * our error with a complaint about that.
823 */
824 conn->inCursor = conn->inStart + 5 + msgLength;
825
826 /*
827 * Return zero to allow input parsing to continue. Subsequent "D"
828 * messages will be ignored until we get to end of data, since an error
829 * result is already set up.
830 */
831 return 0;
832 }
833
834
835 /*
836 * Attempt to read an Error or Notice response message.
837 * This is possible in several places, so we break it out as a subroutine.
838 * Entry: 'E' or 'N' message type and length have already been consumed.
839 * Exit: returns 0 if successfully consumed message.
840 * returns EOF if not enough data.
841 */
842 int
pqGetErrorNotice3(PGconn * conn,bool isError)843 pqGetErrorNotice3(PGconn *conn, bool isError)
844 {
845 PGresult *res = NULL;
846 bool have_position = false;
847 PQExpBufferData workBuf;
848 char id;
849
850 /*
851 * If this is an error message, pre-emptively clear any incomplete query
852 * result we may have. We'd just throw it away below anyway, and
853 * releasing it before collecting the error might avoid out-of-memory.
854 */
855 if (isError)
856 pqClearAsyncResult(conn);
857
858 /*
859 * Since the fields might be pretty long, we create a temporary
860 * PQExpBuffer rather than using conn->workBuffer. workBuffer is intended
861 * for stuff that is expected to be short. We shouldn't use
862 * conn->errorMessage either, since this might be only a notice.
863 */
864 initPQExpBuffer(&workBuf);
865
866 /*
867 * Make a PGresult to hold the accumulated fields. We temporarily lie
868 * about the result status, so that PQmakeEmptyPGresult doesn't uselessly
869 * copy conn->errorMessage.
870 *
871 * NB: This allocation can fail, if you run out of memory. The rest of the
872 * function handles that gracefully, and we still try to set the error
873 * message as the connection's error message.
874 */
875 res = PQmakeEmptyPGresult(conn, PGRES_EMPTY_QUERY);
876 if (res)
877 res->resultStatus = isError ? PGRES_FATAL_ERROR : PGRES_NONFATAL_ERROR;
878
879 /*
880 * Read the fields and save into res.
881 *
882 * While at it, save the SQLSTATE in conn->last_sqlstate, and note whether
883 * we saw a PG_DIAG_STATEMENT_POSITION field.
884 */
885 for (;;)
886 {
887 if (pqGetc(&id, conn))
888 goto fail;
889 if (id == '\0')
890 break; /* terminator found */
891 if (pqGets(&workBuf, conn))
892 goto fail;
893 pqSaveMessageField(res, id, workBuf.data);
894 if (id == PG_DIAG_SQLSTATE)
895 strlcpy(conn->last_sqlstate, workBuf.data,
896 sizeof(conn->last_sqlstate));
897 else if (id == PG_DIAG_STATEMENT_POSITION)
898 have_position = true;
899 }
900
901 /*
902 * Save the active query text, if any, into res as well; but only if we
903 * might need it for an error cursor display, which is only true if there
904 * is a PG_DIAG_STATEMENT_POSITION field.
905 */
906 if (have_position && conn->last_query && res)
907 res->errQuery = pqResultStrdup(res, conn->last_query);
908
909 /*
910 * Now build the "overall" error message for PQresultErrorMessage.
911 */
912 resetPQExpBuffer(&workBuf);
913 pqBuildErrorMessage3(&workBuf, res, conn->verbosity, conn->show_context);
914
915 /*
916 * Either save error as current async result, or just emit the notice.
917 */
918 if (isError)
919 {
920 if (res)
921 res->errMsg = pqResultStrdup(res, workBuf.data);
922 pqClearAsyncResult(conn); /* redundant, but be safe */
923 conn->result = res;
924 if (PQExpBufferDataBroken(workBuf))
925 printfPQExpBuffer(&conn->errorMessage,
926 libpq_gettext("out of memory"));
927 else
928 appendPQExpBufferStr(&conn->errorMessage, workBuf.data);
929 }
930 else
931 {
932 /* if we couldn't allocate the result set, just discard the NOTICE */
933 if (res)
934 {
935 /* We can cheat a little here and not copy the message. */
936 res->errMsg = workBuf.data;
937 if (res->noticeHooks.noticeRec != NULL)
938 res->noticeHooks.noticeRec(res->noticeHooks.noticeRecArg, res);
939 PQclear(res);
940 }
941 }
942
943 termPQExpBuffer(&workBuf);
944 return 0;
945
946 fail:
947 PQclear(res);
948 termPQExpBuffer(&workBuf);
949 return EOF;
950 }
951
952 /*
953 * Construct an error message from the fields in the given PGresult,
954 * appending it to the contents of "msg".
955 */
956 void
pqBuildErrorMessage3(PQExpBuffer msg,const PGresult * res,PGVerbosity verbosity,PGContextVisibility show_context)957 pqBuildErrorMessage3(PQExpBuffer msg, const PGresult *res,
958 PGVerbosity verbosity, PGContextVisibility show_context)
959 {
960 const char *val;
961 const char *querytext = NULL;
962 int querypos = 0;
963
964 /* If we couldn't allocate a PGresult, just say "out of memory" */
965 if (res == NULL)
966 {
967 appendPQExpBuffer(msg, libpq_gettext("out of memory\n"));
968 return;
969 }
970
971 /*
972 * If we don't have any broken-down fields, just return the base message.
973 * This mainly applies if we're given a libpq-generated error result.
974 */
975 if (res->errFields == NULL)
976 {
977 if (res->errMsg && res->errMsg[0])
978 appendPQExpBufferStr(msg, res->errMsg);
979 else
980 appendPQExpBuffer(msg, libpq_gettext("no error message available\n"));
981 return;
982 }
983
984 /* Else build error message from relevant fields */
985 val = PQresultErrorField(res, PG_DIAG_SEVERITY);
986 if (val)
987 appendPQExpBuffer(msg, "%s: ", val);
988
989 if (verbosity == PQERRORS_SQLSTATE)
990 {
991 /*
992 * If we have a SQLSTATE, print that and nothing else. If not (which
993 * shouldn't happen for server-generated errors, but might possibly
994 * happen for libpq-generated ones), fall back to TERSE format, as
995 * that seems better than printing nothing at all.
996 */
997 val = PQresultErrorField(res, PG_DIAG_SQLSTATE);
998 if (val)
999 {
1000 appendPQExpBuffer(msg, "%s\n", val);
1001 return;
1002 }
1003 verbosity = PQERRORS_TERSE;
1004 }
1005
1006 if (verbosity == PQERRORS_VERBOSE)
1007 {
1008 val = PQresultErrorField(res, PG_DIAG_SQLSTATE);
1009 if (val)
1010 appendPQExpBuffer(msg, "%s: ", val);
1011 }
1012 val = PQresultErrorField(res, PG_DIAG_MESSAGE_PRIMARY);
1013 if (val)
1014 appendPQExpBufferStr(msg, val);
1015 val = PQresultErrorField(res, PG_DIAG_STATEMENT_POSITION);
1016 if (val)
1017 {
1018 if (verbosity != PQERRORS_TERSE && res->errQuery != NULL)
1019 {
1020 /* emit position as a syntax cursor display */
1021 querytext = res->errQuery;
1022 querypos = atoi(val);
1023 }
1024 else
1025 {
1026 /* emit position as text addition to primary message */
1027 /* translator: %s represents a digit string */
1028 appendPQExpBuffer(msg, libpq_gettext(" at character %s"),
1029 val);
1030 }
1031 }
1032 else
1033 {
1034 val = PQresultErrorField(res, PG_DIAG_INTERNAL_POSITION);
1035 if (val)
1036 {
1037 querytext = PQresultErrorField(res, PG_DIAG_INTERNAL_QUERY);
1038 if (verbosity != PQERRORS_TERSE && querytext != NULL)
1039 {
1040 /* emit position as a syntax cursor display */
1041 querypos = atoi(val);
1042 }
1043 else
1044 {
1045 /* emit position as text addition to primary message */
1046 /* translator: %s represents a digit string */
1047 appendPQExpBuffer(msg, libpq_gettext(" at character %s"),
1048 val);
1049 }
1050 }
1051 }
1052 appendPQExpBufferChar(msg, '\n');
1053 if (verbosity != PQERRORS_TERSE)
1054 {
1055 if (querytext && querypos > 0)
1056 reportErrorPosition(msg, querytext, querypos,
1057 res->client_encoding);
1058 val = PQresultErrorField(res, PG_DIAG_MESSAGE_DETAIL);
1059 if (val)
1060 appendPQExpBuffer(msg, libpq_gettext("DETAIL: %s\n"), val);
1061 val = PQresultErrorField(res, PG_DIAG_MESSAGE_HINT);
1062 if (val)
1063 appendPQExpBuffer(msg, libpq_gettext("HINT: %s\n"), val);
1064 val = PQresultErrorField(res, PG_DIAG_INTERNAL_QUERY);
1065 if (val)
1066 appendPQExpBuffer(msg, libpq_gettext("QUERY: %s\n"), val);
1067 if (show_context == PQSHOW_CONTEXT_ALWAYS ||
1068 (show_context == PQSHOW_CONTEXT_ERRORS &&
1069 res->resultStatus == PGRES_FATAL_ERROR))
1070 {
1071 val = PQresultErrorField(res, PG_DIAG_CONTEXT);
1072 if (val)
1073 appendPQExpBuffer(msg, libpq_gettext("CONTEXT: %s\n"),
1074 val);
1075 }
1076 }
1077 if (verbosity == PQERRORS_VERBOSE)
1078 {
1079 val = PQresultErrorField(res, PG_DIAG_SCHEMA_NAME);
1080 if (val)
1081 appendPQExpBuffer(msg,
1082 libpq_gettext("SCHEMA NAME: %s\n"), val);
1083 val = PQresultErrorField(res, PG_DIAG_TABLE_NAME);
1084 if (val)
1085 appendPQExpBuffer(msg,
1086 libpq_gettext("TABLE NAME: %s\n"), val);
1087 val = PQresultErrorField(res, PG_DIAG_COLUMN_NAME);
1088 if (val)
1089 appendPQExpBuffer(msg,
1090 libpq_gettext("COLUMN NAME: %s\n"), val);
1091 val = PQresultErrorField(res, PG_DIAG_DATATYPE_NAME);
1092 if (val)
1093 appendPQExpBuffer(msg,
1094 libpq_gettext("DATATYPE NAME: %s\n"), val);
1095 val = PQresultErrorField(res, PG_DIAG_CONSTRAINT_NAME);
1096 if (val)
1097 appendPQExpBuffer(msg,
1098 libpq_gettext("CONSTRAINT NAME: %s\n"), val);
1099 }
1100 if (verbosity == PQERRORS_VERBOSE)
1101 {
1102 const char *valf;
1103 const char *vall;
1104
1105 valf = PQresultErrorField(res, PG_DIAG_SOURCE_FILE);
1106 vall = PQresultErrorField(res, PG_DIAG_SOURCE_LINE);
1107 val = PQresultErrorField(res, PG_DIAG_SOURCE_FUNCTION);
1108 if (val || valf || vall)
1109 {
1110 appendPQExpBufferStr(msg, libpq_gettext("LOCATION: "));
1111 if (val)
1112 appendPQExpBuffer(msg, libpq_gettext("%s, "), val);
1113 if (valf && vall) /* unlikely we'd have just one */
1114 appendPQExpBuffer(msg, libpq_gettext("%s:%s"),
1115 valf, vall);
1116 appendPQExpBufferChar(msg, '\n');
1117 }
1118 }
1119 }
1120
1121 /*
1122 * Add an error-location display to the error message under construction.
1123 *
1124 * The cursor location is measured in logical characters; the query string
1125 * is presumed to be in the specified encoding.
1126 */
1127 static void
reportErrorPosition(PQExpBuffer msg,const char * query,int loc,int encoding)1128 reportErrorPosition(PQExpBuffer msg, const char *query, int loc, int encoding)
1129 {
1130 #define DISPLAY_SIZE 60 /* screen width limit, in screen cols */
1131 #define MIN_RIGHT_CUT 10 /* try to keep this far away from EOL */
1132
1133 char *wquery;
1134 int slen,
1135 cno,
1136 i,
1137 *qidx,
1138 *scridx,
1139 qoffset,
1140 scroffset,
1141 ibeg,
1142 iend,
1143 loc_line;
1144 bool mb_encoding,
1145 beg_trunc,
1146 end_trunc;
1147
1148 /* Convert loc from 1-based to 0-based; no-op if out of range */
1149 loc--;
1150 if (loc < 0)
1151 return;
1152
1153 /* Need a writable copy of the query */
1154 wquery = strdup(query);
1155 if (wquery == NULL)
1156 return; /* fail silently if out of memory */
1157
1158 /*
1159 * Each character might occupy multiple physical bytes in the string, and
1160 * in some Far Eastern character sets it might take more than one screen
1161 * column as well. We compute the starting byte offset and starting
1162 * screen column of each logical character, and store these in qidx[] and
1163 * scridx[] respectively.
1164 */
1165
1166 /* we need a safe allocation size... */
1167 slen = strlen(wquery) + 1;
1168
1169 qidx = (int *) malloc(slen * sizeof(int));
1170 if (qidx == NULL)
1171 {
1172 free(wquery);
1173 return;
1174 }
1175 scridx = (int *) malloc(slen * sizeof(int));
1176 if (scridx == NULL)
1177 {
1178 free(qidx);
1179 free(wquery);
1180 return;
1181 }
1182
1183 /* We can optimize a bit if it's a single-byte encoding */
1184 mb_encoding = (pg_encoding_max_length(encoding) != 1);
1185
1186 /*
1187 * Within the scanning loop, cno is the current character's logical
1188 * number, qoffset is its offset in wquery, and scroffset is its starting
1189 * logical screen column (all indexed from 0). "loc" is the logical
1190 * character number of the error location. We scan to determine loc_line
1191 * (the 1-based line number containing loc) and ibeg/iend (first character
1192 * number and last+1 character number of the line containing loc). Note
1193 * that qidx[] and scridx[] are filled only as far as iend.
1194 */
1195 qoffset = 0;
1196 scroffset = 0;
1197 loc_line = 1;
1198 ibeg = 0;
1199 iend = -1; /* -1 means not set yet */
1200
1201 for (cno = 0; wquery[qoffset] != '\0'; cno++)
1202 {
1203 char ch = wquery[qoffset];
1204
1205 qidx[cno] = qoffset;
1206 scridx[cno] = scroffset;
1207
1208 /*
1209 * Replace tabs with spaces in the writable copy. (Later we might
1210 * want to think about coping with their variable screen width, but
1211 * not today.)
1212 */
1213 if (ch == '\t')
1214 wquery[qoffset] = ' ';
1215
1216 /*
1217 * If end-of-line, count lines and mark positions. Each \r or \n
1218 * counts as a line except when \r \n appear together.
1219 */
1220 else if (ch == '\r' || ch == '\n')
1221 {
1222 if (cno < loc)
1223 {
1224 if (ch == '\r' ||
1225 cno == 0 ||
1226 wquery[qidx[cno - 1]] != '\r')
1227 loc_line++;
1228 /* extract beginning = last line start before loc. */
1229 ibeg = cno + 1;
1230 }
1231 else
1232 {
1233 /* set extract end. */
1234 iend = cno;
1235 /* done scanning. */
1236 break;
1237 }
1238 }
1239
1240 /* Advance */
1241 if (mb_encoding)
1242 {
1243 int w;
1244
1245 w = pg_encoding_dsplen(encoding, &wquery[qoffset]);
1246 /* treat any non-tab control chars as width 1 */
1247 if (w <= 0)
1248 w = 1;
1249 scroffset += w;
1250 qoffset += PQmblenBounded(&wquery[qoffset], encoding);
1251 }
1252 else
1253 {
1254 /* We assume wide chars only exist in multibyte encodings */
1255 scroffset++;
1256 qoffset++;
1257 }
1258 }
1259 /* Fix up if we didn't find an end-of-line after loc */
1260 if (iend < 0)
1261 {
1262 iend = cno; /* query length in chars, +1 */
1263 qidx[iend] = qoffset;
1264 scridx[iend] = scroffset;
1265 }
1266
1267 /* Print only if loc is within computed query length */
1268 if (loc <= cno)
1269 {
1270 /* If the line extracted is too long, we truncate it. */
1271 beg_trunc = false;
1272 end_trunc = false;
1273 if (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE)
1274 {
1275 /*
1276 * We first truncate right if it is enough. This code might be
1277 * off a space or so on enforcing MIN_RIGHT_CUT if there's a wide
1278 * character right there, but that should be okay.
1279 */
1280 if (scridx[ibeg] + DISPLAY_SIZE >= scridx[loc] + MIN_RIGHT_CUT)
1281 {
1282 while (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE)
1283 iend--;
1284 end_trunc = true;
1285 }
1286 else
1287 {
1288 /* Truncate right if not too close to loc. */
1289 while (scridx[loc] + MIN_RIGHT_CUT < scridx[iend])
1290 {
1291 iend--;
1292 end_trunc = true;
1293 }
1294
1295 /* Truncate left if still too long. */
1296 while (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE)
1297 {
1298 ibeg++;
1299 beg_trunc = true;
1300 }
1301 }
1302 }
1303
1304 /* truncate working copy at desired endpoint */
1305 wquery[qidx[iend]] = '\0';
1306
1307 /* Begin building the finished message. */
1308 i = msg->len;
1309 appendPQExpBuffer(msg, libpq_gettext("LINE %d: "), loc_line);
1310 if (beg_trunc)
1311 appendPQExpBufferStr(msg, "...");
1312
1313 /*
1314 * While we have the prefix in the msg buffer, compute its screen
1315 * width.
1316 */
1317 scroffset = 0;
1318 for (; i < msg->len; i += PQmblenBounded(&msg->data[i], encoding))
1319 {
1320 int w = pg_encoding_dsplen(encoding, &msg->data[i]);
1321
1322 if (w <= 0)
1323 w = 1;
1324 scroffset += w;
1325 }
1326
1327 /* Finish up the LINE message line. */
1328 appendPQExpBufferStr(msg, &wquery[qidx[ibeg]]);
1329 if (end_trunc)
1330 appendPQExpBufferStr(msg, "...");
1331 appendPQExpBufferChar(msg, '\n');
1332
1333 /* Now emit the cursor marker line. */
1334 scroffset += scridx[loc] - scridx[ibeg];
1335 for (i = 0; i < scroffset; i++)
1336 appendPQExpBufferChar(msg, ' ');
1337 appendPQExpBufferChar(msg, '^');
1338 appendPQExpBufferChar(msg, '\n');
1339 }
1340
1341 /* Clean up. */
1342 free(scridx);
1343 free(qidx);
1344 free(wquery);
1345 }
1346
1347
1348 /*
1349 * Attempt to read a ParameterStatus message.
1350 * This is possible in several places, so we break it out as a subroutine.
1351 * Entry: 'S' message type and length have already been consumed.
1352 * Exit: returns 0 if successfully consumed message.
1353 * returns EOF if not enough data.
1354 */
1355 static int
getParameterStatus(PGconn * conn)1356 getParameterStatus(PGconn *conn)
1357 {
1358 PQExpBufferData valueBuf;
1359
1360 /* Get the parameter name */
1361 if (pqGets(&conn->workBuffer, conn))
1362 return EOF;
1363 /* Get the parameter value (could be large) */
1364 initPQExpBuffer(&valueBuf);
1365 if (pqGets(&valueBuf, conn))
1366 {
1367 termPQExpBuffer(&valueBuf);
1368 return EOF;
1369 }
1370 /* And save it */
1371 pqSaveParameterStatus(conn, conn->workBuffer.data, valueBuf.data);
1372 termPQExpBuffer(&valueBuf);
1373 return 0;
1374 }
1375
1376
1377 /*
1378 * Attempt to read a Notify response message.
1379 * This is possible in several places, so we break it out as a subroutine.
1380 * Entry: 'A' message type and length have already been consumed.
1381 * Exit: returns 0 if successfully consumed Notify message.
1382 * returns EOF if not enough data.
1383 */
1384 static int
getNotify(PGconn * conn)1385 getNotify(PGconn *conn)
1386 {
1387 int be_pid;
1388 char *svname;
1389 int nmlen;
1390 int extralen;
1391 PGnotify *newNotify;
1392
1393 if (pqGetInt(&be_pid, 4, conn))
1394 return EOF;
1395 if (pqGets(&conn->workBuffer, conn))
1396 return EOF;
1397 /* must save name while getting extra string */
1398 svname = strdup(conn->workBuffer.data);
1399 if (!svname)
1400 return EOF;
1401 if (pqGets(&conn->workBuffer, conn))
1402 {
1403 free(svname);
1404 return EOF;
1405 }
1406
1407 /*
1408 * Store the strings right after the PQnotify structure so it can all be
1409 * freed at once. We don't use NAMEDATALEN because we don't want to tie
1410 * this interface to a specific server name length.
1411 */
1412 nmlen = strlen(svname);
1413 extralen = strlen(conn->workBuffer.data);
1414 newNotify = (PGnotify *) malloc(sizeof(PGnotify) + nmlen + extralen + 2);
1415 if (newNotify)
1416 {
1417 newNotify->relname = (char *) newNotify + sizeof(PGnotify);
1418 strcpy(newNotify->relname, svname);
1419 newNotify->extra = newNotify->relname + nmlen + 1;
1420 strcpy(newNotify->extra, conn->workBuffer.data);
1421 newNotify->be_pid = be_pid;
1422 newNotify->next = NULL;
1423 if (conn->notifyTail)
1424 conn->notifyTail->next = newNotify;
1425 else
1426 conn->notifyHead = newNotify;
1427 conn->notifyTail = newNotify;
1428 }
1429
1430 free(svname);
1431 return 0;
1432 }
1433
1434 /*
1435 * getCopyStart - process CopyInResponse, CopyOutResponse or
1436 * CopyBothResponse message
1437 *
1438 * parseInput already read the message type and length.
1439 */
1440 static int
getCopyStart(PGconn * conn,ExecStatusType copytype)1441 getCopyStart(PGconn *conn, ExecStatusType copytype)
1442 {
1443 PGresult *result;
1444 int nfields;
1445 int i;
1446
1447 result = PQmakeEmptyPGresult(conn, copytype);
1448 if (!result)
1449 goto failure;
1450
1451 if (pqGetc(&conn->copy_is_binary, conn))
1452 goto failure;
1453 result->binary = conn->copy_is_binary;
1454 /* the next two bytes are the number of fields */
1455 if (pqGetInt(&(result->numAttributes), 2, conn))
1456 goto failure;
1457 nfields = result->numAttributes;
1458
1459 /* allocate space for the attribute descriptors */
1460 if (nfields > 0)
1461 {
1462 result->attDescs = (PGresAttDesc *)
1463 pqResultAlloc(result, nfields * sizeof(PGresAttDesc), true);
1464 if (!result->attDescs)
1465 goto failure;
1466 MemSet(result->attDescs, 0, nfields * sizeof(PGresAttDesc));
1467 }
1468
1469 for (i = 0; i < nfields; i++)
1470 {
1471 int format;
1472
1473 if (pqGetInt(&format, 2, conn))
1474 goto failure;
1475
1476 /*
1477 * Since pqGetInt treats 2-byte integers as unsigned, we need to
1478 * coerce these results to signed form.
1479 */
1480 format = (int) ((int16) format);
1481 result->attDescs[i].format = format;
1482 }
1483
1484 /* Success! */
1485 conn->result = result;
1486 return 0;
1487
1488 failure:
1489 PQclear(result);
1490 return EOF;
1491 }
1492
1493 /*
1494 * getReadyForQuery - process ReadyForQuery message
1495 */
1496 static int
getReadyForQuery(PGconn * conn)1497 getReadyForQuery(PGconn *conn)
1498 {
1499 char xact_status;
1500
1501 if (pqGetc(&xact_status, conn))
1502 return EOF;
1503 switch (xact_status)
1504 {
1505 case 'I':
1506 conn->xactStatus = PQTRANS_IDLE;
1507 break;
1508 case 'T':
1509 conn->xactStatus = PQTRANS_INTRANS;
1510 break;
1511 case 'E':
1512 conn->xactStatus = PQTRANS_INERROR;
1513 break;
1514 default:
1515 conn->xactStatus = PQTRANS_UNKNOWN;
1516 break;
1517 }
1518
1519 return 0;
1520 }
1521
1522 /*
1523 * getCopyDataMessage - fetch next CopyData message, process async messages
1524 *
1525 * Returns length word of CopyData message (> 0), or 0 if no complete
1526 * message available, -1 if end of copy, -2 if error.
1527 */
1528 static int
getCopyDataMessage(PGconn * conn)1529 getCopyDataMessage(PGconn *conn)
1530 {
1531 char id;
1532 int msgLength;
1533 int avail;
1534
1535 for (;;)
1536 {
1537 /*
1538 * Do we have the next input message? To make life simpler for async
1539 * callers, we keep returning 0 until the next message is fully
1540 * available, even if it is not Copy Data.
1541 */
1542 conn->inCursor = conn->inStart;
1543 if (pqGetc(&id, conn))
1544 return 0;
1545 if (pqGetInt(&msgLength, 4, conn))
1546 return 0;
1547 if (msgLength < 4)
1548 {
1549 handleSyncLoss(conn, id, msgLength);
1550 return -2;
1551 }
1552 avail = conn->inEnd - conn->inCursor;
1553 if (avail < msgLength - 4)
1554 {
1555 /*
1556 * Before returning, enlarge the input buffer if needed to hold
1557 * the whole message. See notes in parseInput.
1558 */
1559 if (pqCheckInBufferSpace(conn->inCursor + (size_t) msgLength - 4,
1560 conn))
1561 {
1562 /*
1563 * XXX add some better recovery code... plan is to skip over
1564 * the message using its length, then report an error. For the
1565 * moment, just treat this like loss of sync (which indeed it
1566 * might be!)
1567 */
1568 handleSyncLoss(conn, id, msgLength);
1569 return -2;
1570 }
1571 return 0;
1572 }
1573
1574 /*
1575 * If it's a legitimate async message type, process it. (NOTIFY
1576 * messages are not currently possible here, but we handle them for
1577 * completeness.) Otherwise, if it's anything except Copy Data,
1578 * report end-of-copy.
1579 */
1580 switch (id)
1581 {
1582 case 'A': /* NOTIFY */
1583 if (getNotify(conn))
1584 return 0;
1585 break;
1586 case 'N': /* NOTICE */
1587 if (pqGetErrorNotice3(conn, false))
1588 return 0;
1589 break;
1590 case 'S': /* ParameterStatus */
1591 if (getParameterStatus(conn))
1592 return 0;
1593 break;
1594 case 'd': /* Copy Data, pass it back to caller */
1595 return msgLength;
1596 case 'c':
1597
1598 /*
1599 * If this is a CopyDone message, exit COPY_OUT mode and let
1600 * caller read status with PQgetResult(). If we're in
1601 * COPY_BOTH mode, return to COPY_IN mode.
1602 */
1603 if (conn->asyncStatus == PGASYNC_COPY_BOTH)
1604 conn->asyncStatus = PGASYNC_COPY_IN;
1605 else
1606 conn->asyncStatus = PGASYNC_BUSY;
1607 return -1;
1608 default: /* treat as end of copy */
1609
1610 /*
1611 * Any other message terminates either COPY_IN or COPY_BOTH
1612 * mode.
1613 */
1614 conn->asyncStatus = PGASYNC_BUSY;
1615 return -1;
1616 }
1617
1618 /* Drop the processed message and loop around for another */
1619 conn->inStart = conn->inCursor;
1620 }
1621 }
1622
1623 /*
1624 * PQgetCopyData - read a row of data from the backend during COPY OUT
1625 * or COPY BOTH
1626 *
1627 * If successful, sets *buffer to point to a malloc'd row of data, and
1628 * returns row length (always > 0) as result.
1629 * Returns 0 if no row available yet (only possible if async is true),
1630 * -1 if end of copy (consult PQgetResult), or -2 if error (consult
1631 * PQerrorMessage).
1632 */
1633 int
pqGetCopyData3(PGconn * conn,char ** buffer,int async)1634 pqGetCopyData3(PGconn *conn, char **buffer, int async)
1635 {
1636 int msgLength;
1637
1638 for (;;)
1639 {
1640 /*
1641 * Collect the next input message. To make life simpler for async
1642 * callers, we keep returning 0 until the next message is fully
1643 * available, even if it is not Copy Data.
1644 */
1645 msgLength = getCopyDataMessage(conn);
1646 if (msgLength < 0)
1647 return msgLength; /* end-of-copy or error */
1648 if (msgLength == 0)
1649 {
1650 /* Don't block if async read requested */
1651 if (async)
1652 return 0;
1653 /* Need to load more data */
1654 if (pqWait(true, false, conn) ||
1655 pqReadData(conn) < 0)
1656 return -2;
1657 continue;
1658 }
1659
1660 /*
1661 * Drop zero-length messages (shouldn't happen anyway). Otherwise
1662 * pass the data back to the caller.
1663 */
1664 msgLength -= 4;
1665 if (msgLength > 0)
1666 {
1667 *buffer = (char *) malloc(msgLength + 1);
1668 if (*buffer == NULL)
1669 {
1670 printfPQExpBuffer(&conn->errorMessage,
1671 libpq_gettext("out of memory\n"));
1672 return -2;
1673 }
1674 memcpy(*buffer, &conn->inBuffer[conn->inCursor], msgLength);
1675 (*buffer)[msgLength] = '\0'; /* Add terminating null */
1676
1677 /* Mark message consumed */
1678 conn->inStart = conn->inCursor + msgLength;
1679
1680 return msgLength;
1681 }
1682
1683 /* Empty, so drop it and loop around for another */
1684 conn->inStart = conn->inCursor;
1685 }
1686 }
1687
1688 /*
1689 * PQgetline - gets a newline-terminated string from the backend.
1690 *
1691 * See fe-exec.c for documentation.
1692 */
1693 int
pqGetline3(PGconn * conn,char * s,int maxlen)1694 pqGetline3(PGconn *conn, char *s, int maxlen)
1695 {
1696 int status;
1697
1698 if (conn->sock == PGINVALID_SOCKET ||
1699 (conn->asyncStatus != PGASYNC_COPY_OUT &&
1700 conn->asyncStatus != PGASYNC_COPY_BOTH) ||
1701 conn->copy_is_binary)
1702 {
1703 printfPQExpBuffer(&conn->errorMessage,
1704 libpq_gettext("PQgetline: not doing text COPY OUT\n"));
1705 *s = '\0';
1706 return EOF;
1707 }
1708
1709 while ((status = PQgetlineAsync(conn, s, maxlen - 1)) == 0)
1710 {
1711 /* need to load more data */
1712 if (pqWait(true, false, conn) ||
1713 pqReadData(conn) < 0)
1714 {
1715 *s = '\0';
1716 return EOF;
1717 }
1718 }
1719
1720 if (status < 0)
1721 {
1722 /* End of copy detected; gin up old-style terminator */
1723 strcpy(s, "\\.");
1724 return 0;
1725 }
1726
1727 /* Add null terminator, and strip trailing \n if present */
1728 if (s[status - 1] == '\n')
1729 {
1730 s[status - 1] = '\0';
1731 return 0;
1732 }
1733 else
1734 {
1735 s[status] = '\0';
1736 return 1;
1737 }
1738 }
1739
1740 /*
1741 * PQgetlineAsync - gets a COPY data row without blocking.
1742 *
1743 * See fe-exec.c for documentation.
1744 */
1745 int
pqGetlineAsync3(PGconn * conn,char * buffer,int bufsize)1746 pqGetlineAsync3(PGconn *conn, char *buffer, int bufsize)
1747 {
1748 int msgLength;
1749 int avail;
1750
1751 if (conn->asyncStatus != PGASYNC_COPY_OUT
1752 && conn->asyncStatus != PGASYNC_COPY_BOTH)
1753 return -1; /* we are not doing a copy... */
1754
1755 /*
1756 * Recognize the next input message. To make life simpler for async
1757 * callers, we keep returning 0 until the next message is fully available
1758 * even if it is not Copy Data. This should keep PQendcopy from blocking.
1759 * (Note: unlike pqGetCopyData3, we do not change asyncStatus here.)
1760 */
1761 msgLength = getCopyDataMessage(conn);
1762 if (msgLength < 0)
1763 return -1; /* end-of-copy or error */
1764 if (msgLength == 0)
1765 return 0; /* no data yet */
1766
1767 /*
1768 * Move data from libpq's buffer to the caller's. In the case where a
1769 * prior call found the caller's buffer too small, we use
1770 * conn->copy_already_done to remember how much of the row was already
1771 * returned to the caller.
1772 */
1773 conn->inCursor += conn->copy_already_done;
1774 avail = msgLength - 4 - conn->copy_already_done;
1775 if (avail <= bufsize)
1776 {
1777 /* Able to consume the whole message */
1778 memcpy(buffer, &conn->inBuffer[conn->inCursor], avail);
1779 /* Mark message consumed */
1780 conn->inStart = conn->inCursor + avail;
1781 /* Reset state for next time */
1782 conn->copy_already_done = 0;
1783 return avail;
1784 }
1785 else
1786 {
1787 /* We must return a partial message */
1788 memcpy(buffer, &conn->inBuffer[conn->inCursor], bufsize);
1789 /* The message is NOT consumed from libpq's buffer */
1790 conn->copy_already_done += bufsize;
1791 return bufsize;
1792 }
1793 }
1794
1795 /*
1796 * PQendcopy
1797 *
1798 * See fe-exec.c for documentation.
1799 */
1800 int
pqEndcopy3(PGconn * conn)1801 pqEndcopy3(PGconn *conn)
1802 {
1803 PGresult *result;
1804
1805 if (conn->asyncStatus != PGASYNC_COPY_IN &&
1806 conn->asyncStatus != PGASYNC_COPY_OUT &&
1807 conn->asyncStatus != PGASYNC_COPY_BOTH)
1808 {
1809 printfPQExpBuffer(&conn->errorMessage,
1810 libpq_gettext("no COPY in progress\n"));
1811 return 1;
1812 }
1813
1814 /* Send the CopyDone message if needed */
1815 if (conn->asyncStatus == PGASYNC_COPY_IN ||
1816 conn->asyncStatus == PGASYNC_COPY_BOTH)
1817 {
1818 if (pqPutMsgStart('c', false, conn) < 0 ||
1819 pqPutMsgEnd(conn) < 0)
1820 return 1;
1821
1822 /*
1823 * If we sent the COPY command in extended-query mode, we must issue a
1824 * Sync as well.
1825 */
1826 if (conn->queryclass != PGQUERY_SIMPLE)
1827 {
1828 if (pqPutMsgStart('S', false, conn) < 0 ||
1829 pqPutMsgEnd(conn) < 0)
1830 return 1;
1831 }
1832 }
1833
1834 /*
1835 * make sure no data is waiting to be sent, abort if we are non-blocking
1836 * and the flush fails
1837 */
1838 if (pqFlush(conn) && pqIsnonblocking(conn))
1839 return 1;
1840
1841 /* Return to active duty */
1842 conn->asyncStatus = PGASYNC_BUSY;
1843 resetPQExpBuffer(&conn->errorMessage);
1844
1845 /*
1846 * Non blocking connections may have to abort at this point. If everyone
1847 * played the game there should be no problem, but in error scenarios the
1848 * expected messages may not have arrived yet. (We are assuming that the
1849 * backend's packetizing will ensure that CommandComplete arrives along
1850 * with the CopyDone; are there corner cases where that doesn't happen?)
1851 */
1852 if (pqIsnonblocking(conn) && PQisBusy(conn))
1853 return 1;
1854
1855 /* Wait for the completion response */
1856 result = PQgetResult(conn);
1857
1858 /* Expecting a successful result */
1859 if (result && result->resultStatus == PGRES_COMMAND_OK)
1860 {
1861 PQclear(result);
1862 return 0;
1863 }
1864
1865 /*
1866 * Trouble. For backwards-compatibility reasons, we issue the error
1867 * message as if it were a notice (would be nice to get rid of this
1868 * silliness, but too many apps probably don't handle errors from
1869 * PQendcopy reasonably). Note that the app can still obtain the error
1870 * status from the PGconn object.
1871 */
1872 if (conn->errorMessage.len > 0)
1873 {
1874 /* We have to strip the trailing newline ... pain in neck... */
1875 char svLast = conn->errorMessage.data[conn->errorMessage.len - 1];
1876
1877 if (svLast == '\n')
1878 conn->errorMessage.data[conn->errorMessage.len - 1] = '\0';
1879 pqInternalNotice(&conn->noticeHooks, "%s", conn->errorMessage.data);
1880 conn->errorMessage.data[conn->errorMessage.len - 1] = svLast;
1881 }
1882
1883 PQclear(result);
1884
1885 return 1;
1886 }
1887
1888
1889 /*
1890 * PQfn - Send a function call to the POSTGRES backend.
1891 *
1892 * See fe-exec.c for documentation.
1893 */
1894 PGresult *
pqFunctionCall3(PGconn * conn,Oid fnid,int * result_buf,int * actual_result_len,int result_is_int,const PQArgBlock * args,int nargs)1895 pqFunctionCall3(PGconn *conn, Oid fnid,
1896 int *result_buf, int *actual_result_len,
1897 int result_is_int,
1898 const PQArgBlock *args, int nargs)
1899 {
1900 bool needInput = false;
1901 ExecStatusType status = PGRES_FATAL_ERROR;
1902 char id;
1903 int msgLength;
1904 int avail;
1905 int i;
1906
1907 /* PQfn already validated connection state */
1908
1909 if (pqPutMsgStart('F', false, conn) < 0 || /* function call msg */
1910 pqPutInt(fnid, 4, conn) < 0 || /* function id */
1911 pqPutInt(1, 2, conn) < 0 || /* # of format codes */
1912 pqPutInt(1, 2, conn) < 0 || /* format code: BINARY */
1913 pqPutInt(nargs, 2, conn) < 0) /* # of args */
1914 {
1915 /* error message should be set up already */
1916 return NULL;
1917 }
1918
1919 for (i = 0; i < nargs; ++i)
1920 { /* len.int4 + contents */
1921 if (pqPutInt(args[i].len, 4, conn))
1922 return NULL;
1923 if (args[i].len == -1)
1924 continue; /* it's NULL */
1925
1926 if (args[i].isint)
1927 {
1928 if (pqPutInt(args[i].u.integer, args[i].len, conn))
1929 return NULL;
1930 }
1931 else
1932 {
1933 if (pqPutnchar((char *) args[i].u.ptr, args[i].len, conn))
1934 return NULL;
1935 }
1936 }
1937
1938 if (pqPutInt(1, 2, conn) < 0) /* result format code: BINARY */
1939 return NULL;
1940
1941 if (pqPutMsgEnd(conn) < 0 ||
1942 pqFlush(conn))
1943 return NULL;
1944
1945 for (;;)
1946 {
1947 if (needInput)
1948 {
1949 /* Wait for some data to arrive (or for the channel to close) */
1950 if (pqWait(true, false, conn) ||
1951 pqReadData(conn) < 0)
1952 break;
1953 }
1954
1955 /*
1956 * Scan the message. If we run out of data, loop around to try again.
1957 */
1958 needInput = true;
1959
1960 conn->inCursor = conn->inStart;
1961 if (pqGetc(&id, conn))
1962 continue;
1963 if (pqGetInt(&msgLength, 4, conn))
1964 continue;
1965
1966 /*
1967 * Try to validate message type/length here. A length less than 4 is
1968 * definitely broken. Large lengths should only be believed for a few
1969 * message types.
1970 */
1971 if (msgLength < 4)
1972 {
1973 handleSyncLoss(conn, id, msgLength);
1974 break;
1975 }
1976 if (msgLength > 30000 && !VALID_LONG_MESSAGE_TYPE(id))
1977 {
1978 handleSyncLoss(conn, id, msgLength);
1979 break;
1980 }
1981
1982 /*
1983 * Can't process if message body isn't all here yet.
1984 */
1985 msgLength -= 4;
1986 avail = conn->inEnd - conn->inCursor;
1987 if (avail < msgLength)
1988 {
1989 /*
1990 * Before looping, enlarge the input buffer if needed to hold the
1991 * whole message. See notes in parseInput.
1992 */
1993 if (pqCheckInBufferSpace(conn->inCursor + (size_t) msgLength,
1994 conn))
1995 {
1996 /*
1997 * XXX add some better recovery code... plan is to skip over
1998 * the message using its length, then report an error. For the
1999 * moment, just treat this like loss of sync (which indeed it
2000 * might be!)
2001 */
2002 handleSyncLoss(conn, id, msgLength);
2003 break;
2004 }
2005 continue;
2006 }
2007
2008 /*
2009 * We should see V or E response to the command, but might get N
2010 * and/or A notices first. We also need to swallow the final Z before
2011 * returning.
2012 */
2013 switch (id)
2014 {
2015 case 'V': /* function result */
2016 if (pqGetInt(actual_result_len, 4, conn))
2017 continue;
2018 if (*actual_result_len != -1)
2019 {
2020 if (result_is_int)
2021 {
2022 if (pqGetInt(result_buf, *actual_result_len, conn))
2023 continue;
2024 }
2025 else
2026 {
2027 if (pqGetnchar((char *) result_buf,
2028 *actual_result_len,
2029 conn))
2030 continue;
2031 }
2032 }
2033 /* correctly finished function result message */
2034 status = PGRES_COMMAND_OK;
2035 break;
2036 case 'E': /* error return */
2037 if (pqGetErrorNotice3(conn, true))
2038 continue;
2039 status = PGRES_FATAL_ERROR;
2040 break;
2041 case 'A': /* notify message */
2042 /* handle notify and go back to processing return values */
2043 if (getNotify(conn))
2044 continue;
2045 break;
2046 case 'N': /* notice */
2047 /* handle notice and go back to processing return values */
2048 if (pqGetErrorNotice3(conn, false))
2049 continue;
2050 break;
2051 case 'Z': /* backend is ready for new query */
2052 if (getReadyForQuery(conn))
2053 continue;
2054 /* consume the message and exit */
2055 conn->inStart += 5 + msgLength;
2056 /* if we saved a result object (probably an error), use it */
2057 if (conn->result)
2058 return pqPrepareAsyncResult(conn);
2059 return PQmakeEmptyPGresult(conn, status);
2060 case 'S': /* parameter status */
2061 if (getParameterStatus(conn))
2062 continue;
2063 break;
2064 default:
2065 /* The backend violates the protocol. */
2066 printfPQExpBuffer(&conn->errorMessage,
2067 libpq_gettext("protocol error: id=0x%x\n"),
2068 id);
2069 pqSaveErrorResult(conn);
2070 /* trust the specified message length as what to skip */
2071 conn->inStart += 5 + msgLength;
2072 return pqPrepareAsyncResult(conn);
2073 }
2074 /* Completed this message, keep going */
2075 /* trust the specified message length as what to skip */
2076 conn->inStart += 5 + msgLength;
2077 needInput = false;
2078 }
2079
2080 /*
2081 * We fall out of the loop only upon failing to read data.
2082 * conn->errorMessage has been set by pqWait or pqReadData. We want to
2083 * append it to any already-received error message.
2084 */
2085 pqSaveErrorResult(conn);
2086 return pqPrepareAsyncResult(conn);
2087 }
2088
2089
2090 /*
2091 * Construct startup packet
2092 *
2093 * Returns a malloc'd packet buffer, or NULL if out of memory
2094 */
2095 char *
pqBuildStartupPacket3(PGconn * conn,int * packetlen,const PQEnvironmentOption * options)2096 pqBuildStartupPacket3(PGconn *conn, int *packetlen,
2097 const PQEnvironmentOption *options)
2098 {
2099 char *startpacket;
2100
2101 *packetlen = build_startup_packet(conn, NULL, options);
2102 startpacket = (char *) malloc(*packetlen);
2103 if (!startpacket)
2104 return NULL;
2105 *packetlen = build_startup_packet(conn, startpacket, options);
2106 return startpacket;
2107 }
2108
2109 /*
2110 * Build a startup packet given a filled-in PGconn structure.
2111 *
2112 * We need to figure out how much space is needed, then fill it in.
2113 * To avoid duplicate logic, this routine is called twice: the first time
2114 * (with packet == NULL) just counts the space needed, the second time
2115 * (with packet == allocated space) fills it in. Return value is the number
2116 * of bytes used.
2117 */
2118 static int
build_startup_packet(const PGconn * conn,char * packet,const PQEnvironmentOption * options)2119 build_startup_packet(const PGconn *conn, char *packet,
2120 const PQEnvironmentOption *options)
2121 {
2122 int packet_len = 0;
2123 const PQEnvironmentOption *next_eo;
2124 const char *val;
2125
2126 /* Protocol version comes first. */
2127 if (packet)
2128 {
2129 ProtocolVersion pv = pg_hton32(conn->pversion);
2130
2131 memcpy(packet + packet_len, &pv, sizeof(ProtocolVersion));
2132 }
2133 packet_len += sizeof(ProtocolVersion);
2134
2135 /* Add user name, database name, options */
2136
2137 #define ADD_STARTUP_OPTION(optname, optval) \
2138 do { \
2139 if (packet) \
2140 strcpy(packet + packet_len, optname); \
2141 packet_len += strlen(optname) + 1; \
2142 if (packet) \
2143 strcpy(packet + packet_len, optval); \
2144 packet_len += strlen(optval) + 1; \
2145 } while(0)
2146
2147 if (conn->pguser && conn->pguser[0])
2148 ADD_STARTUP_OPTION("user", conn->pguser);
2149 if (conn->dbName && conn->dbName[0])
2150 ADD_STARTUP_OPTION("database", conn->dbName);
2151 if (conn->replication && conn->replication[0])
2152 ADD_STARTUP_OPTION("replication", conn->replication);
2153 if (conn->pgoptions && conn->pgoptions[0])
2154 ADD_STARTUP_OPTION("options", conn->pgoptions);
2155 if (conn->send_appname)
2156 {
2157 /* Use appname if present, otherwise use fallback */
2158 val = conn->appname ? conn->appname : conn->fbappname;
2159 if (val && val[0])
2160 ADD_STARTUP_OPTION("application_name", val);
2161 }
2162
2163 if (conn->client_encoding_initial && conn->client_encoding_initial[0])
2164 ADD_STARTUP_OPTION("client_encoding", conn->client_encoding_initial);
2165
2166 /* Add any environment-driven GUC settings needed */
2167 for (next_eo = options; next_eo->envName; next_eo++)
2168 {
2169 if ((val = getenv(next_eo->envName)) != NULL)
2170 {
2171 if (pg_strcasecmp(val, "default") != 0)
2172 ADD_STARTUP_OPTION(next_eo->pgName, val);
2173 }
2174 }
2175
2176 /* Add trailing terminator */
2177 if (packet)
2178 packet[packet_len] = '\0';
2179 packet_len++;
2180
2181 return packet_len;
2182 }
2183