1 /*-------------------------------------------------------------------------
2 *
3 * fe-exec.c
4 * functions related to sending a query down to the backend
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/interfaces/libpq/fe-exec.c
12 *
13 *-------------------------------------------------------------------------
14 */
15 #include "postgres_fe.h"
16
17 #include <ctype.h>
18 #include <fcntl.h>
19 #include <limits.h>
20
21 #ifdef WIN32
22 #include "win32.h"
23 #else
24 #include <unistd.h>
25 #endif
26
27 #include "libpq-fe.h"
28 #include "libpq-int.h"
29 #include "mb/pg_wchar.h"
30
31 /* keep this in same order as ExecStatusType in libpq-fe.h */
32 char *const pgresStatus[] = {
33 "PGRES_EMPTY_QUERY",
34 "PGRES_COMMAND_OK",
35 "PGRES_TUPLES_OK",
36 "PGRES_COPY_OUT",
37 "PGRES_COPY_IN",
38 "PGRES_BAD_RESPONSE",
39 "PGRES_NONFATAL_ERROR",
40 "PGRES_FATAL_ERROR",
41 "PGRES_COPY_BOTH",
42 "PGRES_SINGLE_TUPLE",
43 "PGRES_PIPELINE_SYNC",
44 "PGRES_PIPELINE_ABORTED"
45 };
46
47 /*
48 * static state needed by PQescapeString and PQescapeBytea; initialize to
49 * values that result in backward-compatible behavior
50 */
51 static int static_client_encoding = PG_SQL_ASCII;
52 static bool static_std_strings = false;
53
54
55 static PGEvent *dupEvents(PGEvent *events, int count, size_t *memSize);
56 static bool pqAddTuple(PGresult *res, PGresAttValue *tup,
57 const char **errmsgp);
58 static int PQsendQueryInternal(PGconn *conn, const char *query, bool newQuery);
59 static bool PQsendQueryStart(PGconn *conn, bool newQuery);
60 static int PQsendQueryGuts(PGconn *conn,
61 const char *command,
62 const char *stmtName,
63 int nParams,
64 const Oid *paramTypes,
65 const char *const *paramValues,
66 const int *paramLengths,
67 const int *paramFormats,
68 int resultFormat);
69 static void parseInput(PGconn *conn);
70 static PGresult *getCopyResult(PGconn *conn, ExecStatusType copytype);
71 static bool PQexecStart(PGconn *conn);
72 static PGresult *PQexecFinish(PGconn *conn);
73 static int PQsendDescribe(PGconn *conn, char desc_type,
74 const char *desc_target);
75 static int check_field_number(const PGresult *res, int field_num);
76 static void pqPipelineProcessQueue(PGconn *conn);
77 static int pqPipelineFlush(PGconn *conn);
78
79
80 /* ----------------
81 * Space management for PGresult.
82 *
83 * Formerly, libpq did a separate malloc() for each field of each tuple
84 * returned by a query. This was remarkably expensive --- malloc/free
85 * consumed a sizable part of the application's runtime. And there is
86 * no real need to keep track of the fields separately, since they will
87 * all be freed together when the PGresult is released. So now, we grab
88 * large blocks of storage from malloc and allocate space for query data
89 * within these blocks, using a trivially simple allocator. This reduces
90 * the number of malloc/free calls dramatically, and it also avoids
91 * fragmentation of the malloc storage arena.
92 * The PGresult structure itself is still malloc'd separately. We could
93 * combine it with the first allocation block, but that would waste space
94 * for the common case that no extra storage is actually needed (that is,
95 * the SQL command did not return tuples).
96 *
97 * We also malloc the top-level array of tuple pointers separately, because
98 * we need to be able to enlarge it via realloc, and our trivial space
99 * allocator doesn't handle that effectively. (Too bad the FE/BE protocol
100 * doesn't tell us up front how many tuples will be returned.)
101 * All other subsidiary storage for a PGresult is kept in PGresult_data blocks
102 * of size PGRESULT_DATA_BLOCKSIZE. The overhead at the start of each block
103 * is just a link to the next one, if any. Free-space management info is
104 * kept in the owning PGresult.
105 * A query returning a small amount of data will thus require three malloc
106 * calls: one for the PGresult, one for the tuples pointer array, and one
107 * PGresult_data block.
108 *
109 * Only the most recently allocated PGresult_data block is a candidate to
110 * have more stuff added to it --- any extra space left over in older blocks
111 * is wasted. We could be smarter and search the whole chain, but the point
112 * here is to be simple and fast. Typical applications do not keep a PGresult
113 * around very long anyway, so some wasted space within one is not a problem.
114 *
115 * Tuning constants for the space allocator are:
116 * PGRESULT_DATA_BLOCKSIZE: size of a standard allocation block, in bytes
117 * PGRESULT_ALIGN_BOUNDARY: assumed alignment requirement for binary data
118 * PGRESULT_SEP_ALLOC_THRESHOLD: objects bigger than this are given separate
119 * blocks, instead of being crammed into a regular allocation block.
120 * Requirements for correct function are:
121 * PGRESULT_ALIGN_BOUNDARY must be a multiple of the alignment requirements
122 * of all machine data types. (Currently this is set from configure
123 * tests, so it should be OK automatically.)
124 * PGRESULT_SEP_ALLOC_THRESHOLD + PGRESULT_BLOCK_OVERHEAD <=
125 * PGRESULT_DATA_BLOCKSIZE
126 * pqResultAlloc assumes an object smaller than the threshold will fit
127 * in a new block.
128 * The amount of space wasted at the end of a block could be as much as
129 * PGRESULT_SEP_ALLOC_THRESHOLD, so it doesn't pay to make that too large.
130 * ----------------
131 */
132
133 #define PGRESULT_DATA_BLOCKSIZE 2048
134 #define PGRESULT_ALIGN_BOUNDARY MAXIMUM_ALIGNOF /* from configure */
135 #define PGRESULT_BLOCK_OVERHEAD Max(sizeof(PGresult_data), PGRESULT_ALIGN_BOUNDARY)
136 #define PGRESULT_SEP_ALLOC_THRESHOLD (PGRESULT_DATA_BLOCKSIZE / 2)
137
138
139 /*
140 * PQmakeEmptyPGresult
141 * returns a newly allocated, initialized PGresult with given status.
142 * If conn is not NULL and status indicates an error, the conn's
143 * errorMessage is copied. Also, any PGEvents are copied from the conn.
144 */
145 PGresult *
PQmakeEmptyPGresult(PGconn * conn,ExecStatusType status)146 PQmakeEmptyPGresult(PGconn *conn, ExecStatusType status)
147 {
148 PGresult *result;
149
150 result = (PGresult *) malloc(sizeof(PGresult));
151 if (!result)
152 return NULL;
153
154 result->ntups = 0;
155 result->numAttributes = 0;
156 result->attDescs = NULL;
157 result->tuples = NULL;
158 result->tupArrSize = 0;
159 result->numParameters = 0;
160 result->paramDescs = NULL;
161 result->resultStatus = status;
162 result->cmdStatus[0] = '\0';
163 result->binary = 0;
164 result->events = NULL;
165 result->nEvents = 0;
166 result->errMsg = NULL;
167 result->errFields = NULL;
168 result->errQuery = NULL;
169 result->null_field[0] = '\0';
170 result->curBlock = NULL;
171 result->curOffset = 0;
172 result->spaceLeft = 0;
173 result->memorySize = sizeof(PGresult);
174
175 if (conn)
176 {
177 /* copy connection data we might need for operations on PGresult */
178 result->noticeHooks = conn->noticeHooks;
179 result->client_encoding = conn->client_encoding;
180
181 /* consider copying conn's errorMessage */
182 switch (status)
183 {
184 case PGRES_EMPTY_QUERY:
185 case PGRES_COMMAND_OK:
186 case PGRES_TUPLES_OK:
187 case PGRES_COPY_OUT:
188 case PGRES_COPY_IN:
189 case PGRES_COPY_BOTH:
190 case PGRES_SINGLE_TUPLE:
191 /* non-error cases */
192 break;
193 default:
194 pqSetResultError(result, &conn->errorMessage);
195 break;
196 }
197
198 /* copy events last; result must be valid if we need to PQclear */
199 if (conn->nEvents > 0)
200 {
201 result->events = dupEvents(conn->events, conn->nEvents,
202 &result->memorySize);
203 if (!result->events)
204 {
205 PQclear(result);
206 return NULL;
207 }
208 result->nEvents = conn->nEvents;
209 }
210 }
211 else
212 {
213 /* defaults... */
214 result->noticeHooks.noticeRec = NULL;
215 result->noticeHooks.noticeRecArg = NULL;
216 result->noticeHooks.noticeProc = NULL;
217 result->noticeHooks.noticeProcArg = NULL;
218 result->client_encoding = PG_SQL_ASCII;
219 }
220
221 return result;
222 }
223
224 /*
225 * PQsetResultAttrs
226 *
227 * Set the attributes for a given result. This function fails if there are
228 * already attributes contained in the provided result. The call is
229 * ignored if numAttributes is zero or attDescs is NULL. If the
230 * function fails, it returns zero. If the function succeeds, it
231 * returns a non-zero value.
232 */
233 int
PQsetResultAttrs(PGresult * res,int numAttributes,PGresAttDesc * attDescs)234 PQsetResultAttrs(PGresult *res, int numAttributes, PGresAttDesc *attDescs)
235 {
236 int i;
237
238 /* If attrs already exist, they cannot be overwritten. */
239 if (!res || res->numAttributes > 0)
240 return false;
241
242 /* ignore no-op request */
243 if (numAttributes <= 0 || !attDescs)
244 return true;
245
246 res->attDescs = (PGresAttDesc *)
247 PQresultAlloc(res, numAttributes * sizeof(PGresAttDesc));
248
249 if (!res->attDescs)
250 return false;
251
252 res->numAttributes = numAttributes;
253 memcpy(res->attDescs, attDescs, numAttributes * sizeof(PGresAttDesc));
254
255 /* deep-copy the attribute names, and determine format */
256 res->binary = 1;
257 for (i = 0; i < res->numAttributes; i++)
258 {
259 if (res->attDescs[i].name)
260 res->attDescs[i].name = pqResultStrdup(res, res->attDescs[i].name);
261 else
262 res->attDescs[i].name = res->null_field;
263
264 if (!res->attDescs[i].name)
265 return false;
266
267 if (res->attDescs[i].format == 0)
268 res->binary = 0;
269 }
270
271 return true;
272 }
273
274 /*
275 * PQcopyResult
276 *
277 * Returns a deep copy of the provided 'src' PGresult, which cannot be NULL.
278 * The 'flags' argument controls which portions of the result will or will
279 * NOT be copied. The created result is always put into the
280 * PGRES_TUPLES_OK status. The source result error message is not copied,
281 * although cmdStatus is.
282 *
283 * To set custom attributes, use PQsetResultAttrs. That function requires
284 * that there are no attrs contained in the result, so to use that
285 * function you cannot use the PG_COPYRES_ATTRS or PG_COPYRES_TUPLES
286 * options with this function.
287 *
288 * Options:
289 * PG_COPYRES_ATTRS - Copy the source result's attributes
290 *
291 * PG_COPYRES_TUPLES - Copy the source result's tuples. This implies
292 * copying the attrs, seeing how the attrs are needed by the tuples.
293 *
294 * PG_COPYRES_EVENTS - Copy the source result's events.
295 *
296 * PG_COPYRES_NOTICEHOOKS - Copy the source result's notice hooks.
297 */
298 PGresult *
PQcopyResult(const PGresult * src,int flags)299 PQcopyResult(const PGresult *src, int flags)
300 {
301 PGresult *dest;
302 int i;
303
304 if (!src)
305 return NULL;
306
307 dest = PQmakeEmptyPGresult(NULL, PGRES_TUPLES_OK);
308 if (!dest)
309 return NULL;
310
311 /* Always copy these over. Is cmdStatus really useful here? */
312 dest->client_encoding = src->client_encoding;
313 strcpy(dest->cmdStatus, src->cmdStatus);
314
315 /* Wants attrs? */
316 if (flags & (PG_COPYRES_ATTRS | PG_COPYRES_TUPLES))
317 {
318 if (!PQsetResultAttrs(dest, src->numAttributes, src->attDescs))
319 {
320 PQclear(dest);
321 return NULL;
322 }
323 }
324
325 /* Wants to copy tuples? */
326 if (flags & PG_COPYRES_TUPLES)
327 {
328 int tup,
329 field;
330
331 for (tup = 0; tup < src->ntups; tup++)
332 {
333 for (field = 0; field < src->numAttributes; field++)
334 {
335 if (!PQsetvalue(dest, tup, field,
336 src->tuples[tup][field].value,
337 src->tuples[tup][field].len))
338 {
339 PQclear(dest);
340 return NULL;
341 }
342 }
343 }
344 }
345
346 /* Wants to copy notice hooks? */
347 if (flags & PG_COPYRES_NOTICEHOOKS)
348 dest->noticeHooks = src->noticeHooks;
349
350 /* Wants to copy PGEvents? */
351 if ((flags & PG_COPYRES_EVENTS) && src->nEvents > 0)
352 {
353 dest->events = dupEvents(src->events, src->nEvents,
354 &dest->memorySize);
355 if (!dest->events)
356 {
357 PQclear(dest);
358 return NULL;
359 }
360 dest->nEvents = src->nEvents;
361 }
362
363 /* Okay, trigger PGEVT_RESULTCOPY event */
364 for (i = 0; i < dest->nEvents; i++)
365 {
366 if (src->events[i].resultInitialized)
367 {
368 PGEventResultCopy evt;
369
370 evt.src = src;
371 evt.dest = dest;
372 if (!dest->events[i].proc(PGEVT_RESULTCOPY, &evt,
373 dest->events[i].passThrough))
374 {
375 PQclear(dest);
376 return NULL;
377 }
378 dest->events[i].resultInitialized = true;
379 }
380 }
381
382 return dest;
383 }
384
385 /*
386 * Copy an array of PGEvents (with no extra space for more).
387 * Does not duplicate the event instance data, sets this to NULL.
388 * Also, the resultInitialized flags are all cleared.
389 * The total space allocated is added to *memSize.
390 */
391 static PGEvent *
dupEvents(PGEvent * events,int count,size_t * memSize)392 dupEvents(PGEvent *events, int count, size_t *memSize)
393 {
394 PGEvent *newEvents;
395 size_t msize;
396 int i;
397
398 if (!events || count <= 0)
399 return NULL;
400
401 msize = count * sizeof(PGEvent);
402 newEvents = (PGEvent *) malloc(msize);
403 if (!newEvents)
404 return NULL;
405
406 for (i = 0; i < count; i++)
407 {
408 newEvents[i].proc = events[i].proc;
409 newEvents[i].passThrough = events[i].passThrough;
410 newEvents[i].data = NULL;
411 newEvents[i].resultInitialized = false;
412 newEvents[i].name = strdup(events[i].name);
413 if (!newEvents[i].name)
414 {
415 while (--i >= 0)
416 free(newEvents[i].name);
417 free(newEvents);
418 return NULL;
419 }
420 msize += strlen(events[i].name) + 1;
421 }
422
423 *memSize += msize;
424 return newEvents;
425 }
426
427
428 /*
429 * Sets the value for a tuple field. The tup_num must be less than or
430 * equal to PQntuples(res). If it is equal, a new tuple is created and
431 * added to the result.
432 * Returns a non-zero value for success and zero for failure.
433 * (On failure, we report the specific problem via pqInternalNotice.)
434 */
435 int
PQsetvalue(PGresult * res,int tup_num,int field_num,char * value,int len)436 PQsetvalue(PGresult *res, int tup_num, int field_num, char *value, int len)
437 {
438 PGresAttValue *attval;
439 const char *errmsg = NULL;
440
441 /* Note that this check also protects us against null "res" */
442 if (!check_field_number(res, field_num))
443 return false;
444
445 /* Invalid tup_num, must be <= ntups */
446 if (tup_num < 0 || tup_num > res->ntups)
447 {
448 pqInternalNotice(&res->noticeHooks,
449 "row number %d is out of range 0..%d",
450 tup_num, res->ntups);
451 return false;
452 }
453
454 /* need to allocate a new tuple? */
455 if (tup_num == res->ntups)
456 {
457 PGresAttValue *tup;
458 int i;
459
460 tup = (PGresAttValue *)
461 pqResultAlloc(res, res->numAttributes * sizeof(PGresAttValue),
462 true);
463
464 if (!tup)
465 goto fail;
466
467 /* initialize each column to NULL */
468 for (i = 0; i < res->numAttributes; i++)
469 {
470 tup[i].len = NULL_LEN;
471 tup[i].value = res->null_field;
472 }
473
474 /* add it to the array */
475 if (!pqAddTuple(res, tup, &errmsg))
476 goto fail;
477 }
478
479 attval = &res->tuples[tup_num][field_num];
480
481 /* treat either NULL_LEN or NULL value pointer as a NULL field */
482 if (len == NULL_LEN || value == NULL)
483 {
484 attval->len = NULL_LEN;
485 attval->value = res->null_field;
486 }
487 else if (len <= 0)
488 {
489 attval->len = 0;
490 attval->value = res->null_field;
491 }
492 else
493 {
494 attval->value = (char *) pqResultAlloc(res, len + 1, true);
495 if (!attval->value)
496 goto fail;
497 attval->len = len;
498 memcpy(attval->value, value, len);
499 attval->value[len] = '\0';
500 }
501
502 return true;
503
504 /*
505 * Report failure via pqInternalNotice. If preceding code didn't provide
506 * an error message, assume "out of memory" was meant.
507 */
508 fail:
509 if (!errmsg)
510 errmsg = libpq_gettext("out of memory");
511 pqInternalNotice(&res->noticeHooks, "%s", errmsg);
512
513 return false;
514 }
515
516 /*
517 * pqResultAlloc - exported routine to allocate local storage in a PGresult.
518 *
519 * We force all such allocations to be maxaligned, since we don't know
520 * whether the value might be binary.
521 */
522 void *
PQresultAlloc(PGresult * res,size_t nBytes)523 PQresultAlloc(PGresult *res, size_t nBytes)
524 {
525 return pqResultAlloc(res, nBytes, true);
526 }
527
528 /*
529 * pqResultAlloc -
530 * Allocate subsidiary storage for a PGresult.
531 *
532 * nBytes is the amount of space needed for the object.
533 * If isBinary is true, we assume that we need to align the object on
534 * a machine allocation boundary.
535 * If isBinary is false, we assume the object is a char string and can
536 * be allocated on any byte boundary.
537 */
538 void *
pqResultAlloc(PGresult * res,size_t nBytes,bool isBinary)539 pqResultAlloc(PGresult *res, size_t nBytes, bool isBinary)
540 {
541 char *space;
542 PGresult_data *block;
543
544 if (!res)
545 return NULL;
546
547 if (nBytes <= 0)
548 return res->null_field;
549
550 /*
551 * If alignment is needed, round up the current position to an alignment
552 * boundary.
553 */
554 if (isBinary)
555 {
556 int offset = res->curOffset % PGRESULT_ALIGN_BOUNDARY;
557
558 if (offset)
559 {
560 res->curOffset += PGRESULT_ALIGN_BOUNDARY - offset;
561 res->spaceLeft -= PGRESULT_ALIGN_BOUNDARY - offset;
562 }
563 }
564
565 /* If there's enough space in the current block, no problem. */
566 if (nBytes <= (size_t) res->spaceLeft)
567 {
568 space = res->curBlock->space + res->curOffset;
569 res->curOffset += nBytes;
570 res->spaceLeft -= nBytes;
571 return space;
572 }
573
574 /*
575 * If the requested object is very large, give it its own block; this
576 * avoids wasting what might be most of the current block to start a new
577 * block. (We'd have to special-case requests bigger than the block size
578 * anyway.) The object is always given binary alignment in this case.
579 */
580 if (nBytes >= PGRESULT_SEP_ALLOC_THRESHOLD)
581 {
582 size_t alloc_size = nBytes + PGRESULT_BLOCK_OVERHEAD;
583
584 block = (PGresult_data *) malloc(alloc_size);
585 if (!block)
586 return NULL;
587 res->memorySize += alloc_size;
588 space = block->space + PGRESULT_BLOCK_OVERHEAD;
589 if (res->curBlock)
590 {
591 /*
592 * Tuck special block below the active block, so that we don't
593 * have to waste the free space in the active block.
594 */
595 block->next = res->curBlock->next;
596 res->curBlock->next = block;
597 }
598 else
599 {
600 /* Must set up the new block as the first active block. */
601 block->next = NULL;
602 res->curBlock = block;
603 res->spaceLeft = 0; /* be sure it's marked full */
604 }
605 return space;
606 }
607
608 /* Otherwise, start a new block. */
609 block = (PGresult_data *) malloc(PGRESULT_DATA_BLOCKSIZE);
610 if (!block)
611 return NULL;
612 res->memorySize += PGRESULT_DATA_BLOCKSIZE;
613 block->next = res->curBlock;
614 res->curBlock = block;
615 if (isBinary)
616 {
617 /* object needs full alignment */
618 res->curOffset = PGRESULT_BLOCK_OVERHEAD;
619 res->spaceLeft = PGRESULT_DATA_BLOCKSIZE - PGRESULT_BLOCK_OVERHEAD;
620 }
621 else
622 {
623 /* we can cram it right after the overhead pointer */
624 res->curOffset = sizeof(PGresult_data);
625 res->spaceLeft = PGRESULT_DATA_BLOCKSIZE - sizeof(PGresult_data);
626 }
627
628 space = block->space + res->curOffset;
629 res->curOffset += nBytes;
630 res->spaceLeft -= nBytes;
631 return space;
632 }
633
634 /*
635 * PQresultMemorySize -
636 * Returns total space allocated for the PGresult.
637 */
638 size_t
PQresultMemorySize(const PGresult * res)639 PQresultMemorySize(const PGresult *res)
640 {
641 if (!res)
642 return 0;
643 return res->memorySize;
644 }
645
646 /*
647 * pqResultStrdup -
648 * Like strdup, but the space is subsidiary PGresult space.
649 */
650 char *
pqResultStrdup(PGresult * res,const char * str)651 pqResultStrdup(PGresult *res, const char *str)
652 {
653 char *space = (char *) pqResultAlloc(res, strlen(str) + 1, false);
654
655 if (space)
656 strcpy(space, str);
657 return space;
658 }
659
660 /*
661 * pqSetResultError -
662 * assign a new error message to a PGresult
663 */
664 void
pqSetResultError(PGresult * res,PQExpBuffer errorMessage)665 pqSetResultError(PGresult *res, PQExpBuffer errorMessage)
666 {
667 char *msg;
668
669 if (!res)
670 return;
671
672 /*
673 * We handle two OOM scenarios here. The errorMessage buffer might be
674 * marked "broken" due to having previously failed to allocate enough
675 * memory for the message, or it might be fine but pqResultStrdup fails
676 * and returns NULL. In either case, just make res->errMsg point directly
677 * at a constant "out of memory" string.
678 */
679 if (!PQExpBufferBroken(errorMessage))
680 msg = pqResultStrdup(res, errorMessage->data);
681 else
682 msg = NULL;
683 if (msg)
684 res->errMsg = msg;
685 else
686 res->errMsg = libpq_gettext("out of memory\n");
687 }
688
689 /*
690 * PQclear -
691 * free's the memory associated with a PGresult
692 */
693 void
PQclear(PGresult * res)694 PQclear(PGresult *res)
695 {
696 PGresult_data *block;
697 int i;
698
699 if (!res)
700 return;
701
702 for (i = 0; i < res->nEvents; i++)
703 {
704 /* only send DESTROY to successfully-initialized event procs */
705 if (res->events[i].resultInitialized)
706 {
707 PGEventResultDestroy evt;
708
709 evt.result = res;
710 (void) res->events[i].proc(PGEVT_RESULTDESTROY, &evt,
711 res->events[i].passThrough);
712 }
713 free(res->events[i].name);
714 }
715
716 if (res->events)
717 free(res->events);
718
719 /* Free all the subsidiary blocks */
720 while ((block = res->curBlock) != NULL)
721 {
722 res->curBlock = block->next;
723 free(block);
724 }
725
726 /* Free the top-level tuple pointer array */
727 if (res->tuples)
728 free(res->tuples);
729
730 /* zero out the pointer fields to catch programming errors */
731 res->attDescs = NULL;
732 res->tuples = NULL;
733 res->paramDescs = NULL;
734 res->errFields = NULL;
735 res->events = NULL;
736 res->nEvents = 0;
737 /* res->curBlock was zeroed out earlier */
738
739 /* Free the PGresult structure itself */
740 free(res);
741 }
742
743 /*
744 * Handy subroutine to deallocate any partially constructed async result.
745 *
746 * Any "next" result gets cleared too.
747 */
748 void
pqClearAsyncResult(PGconn * conn)749 pqClearAsyncResult(PGconn *conn)
750 {
751 if (conn->result)
752 PQclear(conn->result);
753 conn->result = NULL;
754 if (conn->next_result)
755 PQclear(conn->next_result);
756 conn->next_result = NULL;
757 }
758
759 /*
760 * This subroutine deletes any existing async result, sets conn->result
761 * to a PGresult with status PGRES_FATAL_ERROR, and stores the current
762 * contents of conn->errorMessage into that result.
763 */
764 void
pqSaveErrorResult(PGconn * conn)765 pqSaveErrorResult(PGconn *conn)
766 {
767 pqClearAsyncResult(conn);
768 conn->result = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
769 }
770
771 /*
772 * As above, after appending conn->write_err_msg to whatever other error we
773 * have. This is used when we've detected a write failure and have exhausted
774 * our chances of reporting something else instead.
775 */
776 static void
pqSaveWriteError(PGconn * conn)777 pqSaveWriteError(PGconn *conn)
778 {
779 /*
780 * If write_err_msg is null because of previous strdup failure, do what we
781 * can. (It's likely our machinations here will get OOM failures as well,
782 * but might as well try.)
783 */
784 if (conn->write_err_msg)
785 {
786 appendPQExpBufferStr(&conn->errorMessage, conn->write_err_msg);
787 /* Avoid possibly appending the same message twice */
788 conn->write_err_msg[0] = '\0';
789 }
790 else
791 appendPQExpBufferStr(&conn->errorMessage,
792 libpq_gettext("write to server failed\n"));
793
794 pqSaveErrorResult(conn);
795 }
796
797 /*
798 * This subroutine prepares an async result object for return to the caller.
799 * If there is not already an async result object, build an error object
800 * using whatever is in conn->errorMessage. In any case, clear the async
801 * result storage.
802 */
803 PGresult *
pqPrepareAsyncResult(PGconn * conn)804 pqPrepareAsyncResult(PGconn *conn)
805 {
806 PGresult *res;
807
808 /*
809 * conn->result is the PGresult to return. If it is NULL (which probably
810 * shouldn't happen) we assume there is an appropriate error message in
811 * conn->errorMessage.
812 */
813 res = conn->result;
814 if (!res)
815 res = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
816
817 /*
818 * Replace conn->result with next_result, if any. In the normal case
819 * there isn't a next result and we're just dropping ownership of the
820 * current result. In single-row mode this restores the situation to what
821 * it was before we created the current single-row result.
822 */
823 conn->result = conn->next_result;
824 conn->next_result = NULL;
825
826 return res;
827 }
828
829 /*
830 * pqInternalNotice - produce an internally-generated notice message
831 *
832 * A format string and optional arguments can be passed. Note that we do
833 * libpq_gettext() here, so callers need not.
834 *
835 * The supplied text is taken as primary message (ie., it should not include
836 * a trailing newline, and should not be more than one line).
837 */
838 void
pqInternalNotice(const PGNoticeHooks * hooks,const char * fmt,...)839 pqInternalNotice(const PGNoticeHooks *hooks, const char *fmt,...)
840 {
841 char msgBuf[1024];
842 va_list args;
843 PGresult *res;
844
845 if (hooks->noticeRec == NULL)
846 return; /* nobody home to receive notice? */
847
848 /* Format the message */
849 va_start(args, fmt);
850 vsnprintf(msgBuf, sizeof(msgBuf), libpq_gettext(fmt), args);
851 va_end(args);
852 msgBuf[sizeof(msgBuf) - 1] = '\0'; /* make real sure it's terminated */
853
854 /* Make a PGresult to pass to the notice receiver */
855 res = PQmakeEmptyPGresult(NULL, PGRES_NONFATAL_ERROR);
856 if (!res)
857 return;
858 res->noticeHooks = *hooks;
859
860 /*
861 * Set up fields of notice.
862 */
863 pqSaveMessageField(res, PG_DIAG_MESSAGE_PRIMARY, msgBuf);
864 pqSaveMessageField(res, PG_DIAG_SEVERITY, libpq_gettext("NOTICE"));
865 pqSaveMessageField(res, PG_DIAG_SEVERITY_NONLOCALIZED, "NOTICE");
866 /* XXX should provide a SQLSTATE too? */
867
868 /*
869 * Result text is always just the primary message + newline. If we can't
870 * allocate it, substitute "out of memory", as in pqSetResultError.
871 */
872 res->errMsg = (char *) pqResultAlloc(res, strlen(msgBuf) + 2, false);
873 if (res->errMsg)
874 sprintf(res->errMsg, "%s\n", msgBuf);
875 else
876 res->errMsg = libpq_gettext("out of memory\n");
877
878 /*
879 * Pass to receiver, then free it.
880 */
881 res->noticeHooks.noticeRec(res->noticeHooks.noticeRecArg, res);
882 PQclear(res);
883 }
884
885 /*
886 * pqAddTuple
887 * add a row pointer to the PGresult structure, growing it if necessary
888 * Returns true if OK, false if an error prevented adding the row
889 *
890 * On error, *errmsgp can be set to an error string to be returned.
891 * If it is left NULL, the error is presumed to be "out of memory".
892 */
893 static bool
pqAddTuple(PGresult * res,PGresAttValue * tup,const char ** errmsgp)894 pqAddTuple(PGresult *res, PGresAttValue *tup, const char **errmsgp)
895 {
896 if (res->ntups >= res->tupArrSize)
897 {
898 /*
899 * Try to grow the array.
900 *
901 * We can use realloc because shallow copying of the structure is
902 * okay. Note that the first time through, res->tuples is NULL. While
903 * ANSI says that realloc() should act like malloc() in that case,
904 * some old C libraries (like SunOS 4.1.x) coredump instead. On
905 * failure realloc is supposed to return NULL without damaging the
906 * existing allocation. Note that the positions beyond res->ntups are
907 * garbage, not necessarily NULL.
908 */
909 int newSize;
910 PGresAttValue **newTuples;
911
912 /*
913 * Since we use integers for row numbers, we can't support more than
914 * INT_MAX rows. Make sure we allow that many, though.
915 */
916 if (res->tupArrSize <= INT_MAX / 2)
917 newSize = (res->tupArrSize > 0) ? res->tupArrSize * 2 : 128;
918 else if (res->tupArrSize < INT_MAX)
919 newSize = INT_MAX;
920 else
921 {
922 *errmsgp = libpq_gettext("PGresult cannot support more than INT_MAX tuples");
923 return false;
924 }
925
926 /*
927 * Also, on 32-bit platforms we could, in theory, overflow size_t even
928 * before newSize gets to INT_MAX. (In practice we'd doubtless hit
929 * OOM long before that, but let's check.)
930 */
931 #if INT_MAX >= (SIZE_MAX / 2)
932 if (newSize > SIZE_MAX / sizeof(PGresAttValue *))
933 {
934 *errmsgp = libpq_gettext("size_t overflow");
935 return false;
936 }
937 #endif
938
939 if (res->tuples == NULL)
940 newTuples = (PGresAttValue **)
941 malloc(newSize * sizeof(PGresAttValue *));
942 else
943 newTuples = (PGresAttValue **)
944 realloc(res->tuples, newSize * sizeof(PGresAttValue *));
945 if (!newTuples)
946 return false; /* malloc or realloc failed */
947 res->memorySize +=
948 (newSize - res->tupArrSize) * sizeof(PGresAttValue *);
949 res->tupArrSize = newSize;
950 res->tuples = newTuples;
951 }
952 res->tuples[res->ntups] = tup;
953 res->ntups++;
954 return true;
955 }
956
957 /*
958 * pqSaveMessageField - save one field of an error or notice message
959 */
960 void
pqSaveMessageField(PGresult * res,char code,const char * value)961 pqSaveMessageField(PGresult *res, char code, const char *value)
962 {
963 PGMessageField *pfield;
964
965 pfield = (PGMessageField *)
966 pqResultAlloc(res,
967 offsetof(PGMessageField, contents) +
968 strlen(value) + 1,
969 true);
970 if (!pfield)
971 return; /* out of memory? */
972 pfield->code = code;
973 strcpy(pfield->contents, value);
974 pfield->next = res->errFields;
975 res->errFields = pfield;
976 }
977
978 /*
979 * pqSaveParameterStatus - remember parameter status sent by backend
980 */
981 void
pqSaveParameterStatus(PGconn * conn,const char * name,const char * value)982 pqSaveParameterStatus(PGconn *conn, const char *name, const char *value)
983 {
984 pgParameterStatus *pstatus;
985 pgParameterStatus *prev;
986
987 /*
988 * Forget any old information about the parameter
989 */
990 for (pstatus = conn->pstatus, prev = NULL;
991 pstatus != NULL;
992 prev = pstatus, pstatus = pstatus->next)
993 {
994 if (strcmp(pstatus->name, name) == 0)
995 {
996 if (prev)
997 prev->next = pstatus->next;
998 else
999 conn->pstatus = pstatus->next;
1000 free(pstatus); /* frees name and value strings too */
1001 break;
1002 }
1003 }
1004
1005 /*
1006 * Store new info as a single malloc block
1007 */
1008 pstatus = (pgParameterStatus *) malloc(sizeof(pgParameterStatus) +
1009 strlen(name) + strlen(value) + 2);
1010 if (pstatus)
1011 {
1012 char *ptr;
1013
1014 ptr = ((char *) pstatus) + sizeof(pgParameterStatus);
1015 pstatus->name = ptr;
1016 strcpy(ptr, name);
1017 ptr += strlen(name) + 1;
1018 pstatus->value = ptr;
1019 strcpy(ptr, value);
1020 pstatus->next = conn->pstatus;
1021 conn->pstatus = pstatus;
1022 }
1023
1024 /*
1025 * Save values of settings that are of interest to libpq in fields of the
1026 * PGconn object. We keep client_encoding and standard_conforming_strings
1027 * in static variables as well, so that PQescapeString and PQescapeBytea
1028 * can behave somewhat sanely (at least in single-connection-using
1029 * programs).
1030 */
1031 if (strcmp(name, "client_encoding") == 0)
1032 {
1033 conn->client_encoding = pg_char_to_encoding(value);
1034 /* if we don't recognize the encoding name, fall back to SQL_ASCII */
1035 if (conn->client_encoding < 0)
1036 conn->client_encoding = PG_SQL_ASCII;
1037 static_client_encoding = conn->client_encoding;
1038 }
1039 else if (strcmp(name, "standard_conforming_strings") == 0)
1040 {
1041 conn->std_strings = (strcmp(value, "on") == 0);
1042 static_std_strings = conn->std_strings;
1043 }
1044 else if (strcmp(name, "server_version") == 0)
1045 {
1046 /* We convert the server version to numeric form. */
1047 int cnt;
1048 int vmaj,
1049 vmin,
1050 vrev;
1051
1052 cnt = sscanf(value, "%d.%d.%d", &vmaj, &vmin, &vrev);
1053
1054 if (cnt == 3)
1055 {
1056 /* old style, e.g. 9.6.1 */
1057 conn->sversion = (100 * vmaj + vmin) * 100 + vrev;
1058 }
1059 else if (cnt == 2)
1060 {
1061 if (vmaj >= 10)
1062 {
1063 /* new style, e.g. 10.1 */
1064 conn->sversion = 100 * 100 * vmaj + vmin;
1065 }
1066 else
1067 {
1068 /* old style without minor version, e.g. 9.6devel */
1069 conn->sversion = (100 * vmaj + vmin) * 100;
1070 }
1071 }
1072 else if (cnt == 1)
1073 {
1074 /* new style without minor version, e.g. 10devel */
1075 conn->sversion = 100 * 100 * vmaj;
1076 }
1077 else
1078 conn->sversion = 0; /* unknown */
1079 }
1080 else if (strcmp(name, "default_transaction_read_only") == 0)
1081 {
1082 conn->default_transaction_read_only =
1083 (strcmp(value, "on") == 0) ? PG_BOOL_YES : PG_BOOL_NO;
1084 }
1085 else if (strcmp(name, "in_hot_standby") == 0)
1086 {
1087 conn->in_hot_standby =
1088 (strcmp(value, "on") == 0) ? PG_BOOL_YES : PG_BOOL_NO;
1089 }
1090 }
1091
1092
1093 /*
1094 * pqRowProcessor
1095 * Add the received row to the current async result (conn->result).
1096 * Returns 1 if OK, 0 if error occurred.
1097 *
1098 * On error, *errmsgp can be set to an error string to be returned.
1099 * If it is left NULL, the error is presumed to be "out of memory".
1100 *
1101 * In single-row mode, we create a new result holding just the current row,
1102 * stashing the previous result in conn->next_result so that it becomes
1103 * active again after pqPrepareAsyncResult(). This allows the result metadata
1104 * (column descriptions) to be carried forward to each result row.
1105 */
1106 int
pqRowProcessor(PGconn * conn,const char ** errmsgp)1107 pqRowProcessor(PGconn *conn, const char **errmsgp)
1108 {
1109 PGresult *res = conn->result;
1110 int nfields = res->numAttributes;
1111 const PGdataValue *columns = conn->rowBuf;
1112 PGresAttValue *tup;
1113 int i;
1114
1115 /*
1116 * In single-row mode, make a new PGresult that will hold just this one
1117 * row; the original conn->result is left unchanged so that it can be used
1118 * again as the template for future rows.
1119 */
1120 if (conn->singleRowMode)
1121 {
1122 /* Copy everything that should be in the result at this point */
1123 res = PQcopyResult(res,
1124 PG_COPYRES_ATTRS | PG_COPYRES_EVENTS |
1125 PG_COPYRES_NOTICEHOOKS);
1126 if (!res)
1127 return 0;
1128 }
1129
1130 /*
1131 * Basically we just allocate space in the PGresult for each field and
1132 * copy the data over.
1133 *
1134 * Note: on malloc failure, we return 0 leaving *errmsgp still NULL, which
1135 * caller will take to mean "out of memory". This is preferable to trying
1136 * to set up such a message here, because evidently there's not enough
1137 * memory for gettext() to do anything.
1138 */
1139 tup = (PGresAttValue *)
1140 pqResultAlloc(res, nfields * sizeof(PGresAttValue), true);
1141 if (tup == NULL)
1142 goto fail;
1143
1144 for (i = 0; i < nfields; i++)
1145 {
1146 int clen = columns[i].len;
1147
1148 if (clen < 0)
1149 {
1150 /* null field */
1151 tup[i].len = NULL_LEN;
1152 tup[i].value = res->null_field;
1153 }
1154 else
1155 {
1156 bool isbinary = (res->attDescs[i].format != 0);
1157 char *val;
1158
1159 val = (char *) pqResultAlloc(res, clen + 1, isbinary);
1160 if (val == NULL)
1161 goto fail;
1162
1163 /* copy and zero-terminate the data (even if it's binary) */
1164 memcpy(val, columns[i].value, clen);
1165 val[clen] = '\0';
1166
1167 tup[i].len = clen;
1168 tup[i].value = val;
1169 }
1170 }
1171
1172 /* And add the tuple to the PGresult's tuple array */
1173 if (!pqAddTuple(res, tup, errmsgp))
1174 goto fail;
1175
1176 /*
1177 * Success. In single-row mode, make the result available to the client
1178 * immediately.
1179 */
1180 if (conn->singleRowMode)
1181 {
1182 /* Change result status to special single-row value */
1183 res->resultStatus = PGRES_SINGLE_TUPLE;
1184 /* Stash old result for re-use later */
1185 conn->next_result = conn->result;
1186 conn->result = res;
1187 /* And mark the result ready to return */
1188 conn->asyncStatus = PGASYNC_READY_MORE;
1189 }
1190
1191 return 1;
1192
1193 fail:
1194 /* release locally allocated PGresult, if we made one */
1195 if (res != conn->result)
1196 PQclear(res);
1197 return 0;
1198 }
1199
1200
1201 /*
1202 * pqAllocCmdQueueEntry
1203 * Get a command queue entry for caller to fill.
1204 *
1205 * If the recycle queue has a free element, that is returned; if not, a
1206 * fresh one is allocated. Caller is responsible for adding it to the
1207 * command queue (pqAppendCmdQueueEntry) once the struct is filled in, or
1208 * releasing the memory (pqRecycleCmdQueueEntry) if an error occurs.
1209 *
1210 * If allocation fails, sets the error message and returns NULL.
1211 */
1212 static PGcmdQueueEntry *
pqAllocCmdQueueEntry(PGconn * conn)1213 pqAllocCmdQueueEntry(PGconn *conn)
1214 {
1215 PGcmdQueueEntry *entry;
1216
1217 if (conn->cmd_queue_recycle == NULL)
1218 {
1219 entry = (PGcmdQueueEntry *) malloc(sizeof(PGcmdQueueEntry));
1220 if (entry == NULL)
1221 {
1222 appendPQExpBufferStr(&conn->errorMessage,
1223 libpq_gettext("out of memory\n"));
1224 return NULL;
1225 }
1226 }
1227 else
1228 {
1229 entry = conn->cmd_queue_recycle;
1230 conn->cmd_queue_recycle = entry->next;
1231 }
1232 entry->next = NULL;
1233 entry->query = NULL;
1234
1235 return entry;
1236 }
1237
1238 /*
1239 * pqAppendCmdQueueEntry
1240 * Append a caller-allocated entry to the command queue, and update
1241 * conn->asyncStatus to account for it.
1242 *
1243 * The query itself must already have been put in the output buffer by the
1244 * caller.
1245 */
1246 static void
pqAppendCmdQueueEntry(PGconn * conn,PGcmdQueueEntry * entry)1247 pqAppendCmdQueueEntry(PGconn *conn, PGcmdQueueEntry *entry)
1248 {
1249 Assert(entry->next == NULL);
1250
1251 if (conn->cmd_queue_head == NULL)
1252 conn->cmd_queue_head = entry;
1253 else
1254 conn->cmd_queue_tail->next = entry;
1255
1256 conn->cmd_queue_tail = entry;
1257
1258 switch (conn->pipelineStatus)
1259 {
1260 case PQ_PIPELINE_OFF:
1261 case PQ_PIPELINE_ON:
1262
1263 /*
1264 * When not in pipeline aborted state, if there's a result ready
1265 * to be consumed, let it be so (that is, don't change away from
1266 * READY or READY_MORE); otherwise set us busy to wait for
1267 * something to arrive from the server.
1268 */
1269 if (conn->asyncStatus == PGASYNC_IDLE)
1270 conn->asyncStatus = PGASYNC_BUSY;
1271 break;
1272
1273 case PQ_PIPELINE_ABORTED:
1274
1275 /*
1276 * In aborted pipeline state, we don't expect anything from the
1277 * server (since we don't send any queries that are queued).
1278 * Therefore, if IDLE then do what PQgetResult would do to let
1279 * itself consume commands from the queue; if we're in any other
1280 * state, we don't have to do anything.
1281 */
1282 if (conn->asyncStatus == PGASYNC_IDLE)
1283 {
1284 resetPQExpBuffer(&conn->errorMessage);
1285 pqPipelineProcessQueue(conn);
1286 }
1287 break;
1288 }
1289 }
1290
1291 /*
1292 * pqRecycleCmdQueueEntry
1293 * Push a command queue entry onto the freelist.
1294 */
1295 static void
pqRecycleCmdQueueEntry(PGconn * conn,PGcmdQueueEntry * entry)1296 pqRecycleCmdQueueEntry(PGconn *conn, PGcmdQueueEntry *entry)
1297 {
1298 if (entry == NULL)
1299 return;
1300
1301 /* recyclable entries should not have a follow-on command */
1302 Assert(entry->next == NULL);
1303
1304 if (entry->query)
1305 {
1306 free(entry->query);
1307 entry->query = NULL;
1308 }
1309
1310 entry->next = conn->cmd_queue_recycle;
1311 conn->cmd_queue_recycle = entry;
1312 }
1313
1314
1315 /*
1316 * PQsendQuery
1317 * Submit a query, but don't wait for it to finish
1318 *
1319 * Returns: 1 if successfully submitted
1320 * 0 if error (conn->errorMessage is set)
1321 *
1322 * PQsendQueryContinue is a non-exported version that behaves identically
1323 * except that it doesn't reset conn->errorMessage.
1324 */
1325 int
PQsendQuery(PGconn * conn,const char * query)1326 PQsendQuery(PGconn *conn, const char *query)
1327 {
1328 return PQsendQueryInternal(conn, query, true);
1329 }
1330
1331 int
PQsendQueryContinue(PGconn * conn,const char * query)1332 PQsendQueryContinue(PGconn *conn, const char *query)
1333 {
1334 return PQsendQueryInternal(conn, query, false);
1335 }
1336
1337 static int
PQsendQueryInternal(PGconn * conn,const char * query,bool newQuery)1338 PQsendQueryInternal(PGconn *conn, const char *query, bool newQuery)
1339 {
1340 PGcmdQueueEntry *entry = NULL;
1341
1342 if (!PQsendQueryStart(conn, newQuery))
1343 return 0;
1344
1345 /* check the argument */
1346 if (!query)
1347 {
1348 appendPQExpBufferStr(&conn->errorMessage,
1349 libpq_gettext("command string is a null pointer\n"));
1350 return 0;
1351 }
1352
1353 entry = pqAllocCmdQueueEntry(conn);
1354 if (entry == NULL)
1355 return 0; /* error msg already set */
1356
1357 /* Send the query message(s) */
1358 if (conn->pipelineStatus == PQ_PIPELINE_OFF)
1359 {
1360 /* construct the outgoing Query message */
1361 if (pqPutMsgStart('Q', conn) < 0 ||
1362 pqPuts(query, conn) < 0 ||
1363 pqPutMsgEnd(conn) < 0)
1364 {
1365 /* error message should be set up already */
1366 pqRecycleCmdQueueEntry(conn, entry);
1367 return 0;
1368 }
1369
1370 /* remember we are using simple query protocol */
1371 entry->queryclass = PGQUERY_SIMPLE;
1372 /* and remember the query text too, if possible */
1373 entry->query = strdup(query);
1374 }
1375 else
1376 {
1377 /*
1378 * In pipeline mode we cannot use the simple protocol, so we send
1379 * Parse, Bind, Describe Portal, Execute, Close Portal (with the
1380 * unnamed portal).
1381 */
1382 if (pqPutMsgStart('P', conn) < 0 ||
1383 pqPuts("", conn) < 0 ||
1384 pqPuts(query, conn) < 0 ||
1385 pqPutInt(0, 2, conn) < 0 ||
1386 pqPutMsgEnd(conn) < 0)
1387 goto sendFailed;
1388 if (pqPutMsgStart('B', conn) < 0 ||
1389 pqPuts("", conn) < 0 ||
1390 pqPuts("", conn) < 0 ||
1391 pqPutInt(0, 2, conn) < 0 ||
1392 pqPutInt(0, 2, conn) < 0 ||
1393 pqPutInt(0, 2, conn) < 0 ||
1394 pqPutMsgEnd(conn) < 0)
1395 goto sendFailed;
1396 if (pqPutMsgStart('D', conn) < 0 ||
1397 pqPutc('P', conn) < 0 ||
1398 pqPuts("", conn) < 0 ||
1399 pqPutMsgEnd(conn) < 0)
1400 goto sendFailed;
1401 if (pqPutMsgStart('E', conn) < 0 ||
1402 pqPuts("", conn) < 0 ||
1403 pqPutInt(0, 4, conn) < 0 ||
1404 pqPutMsgEnd(conn) < 0)
1405 goto sendFailed;
1406 if (pqPutMsgStart('C', conn) < 0 ||
1407 pqPutc('P', conn) < 0 ||
1408 pqPuts("", conn) < 0 ||
1409 pqPutMsgEnd(conn) < 0)
1410 goto sendFailed;
1411
1412 entry->queryclass = PGQUERY_EXTENDED;
1413 entry->query = strdup(query);
1414 }
1415
1416 /*
1417 * Give the data a push. In nonblock mode, don't complain if we're unable
1418 * to send it all; PQgetResult() will do any additional flushing needed.
1419 */
1420 if (pqPipelineFlush(conn) < 0)
1421 goto sendFailed;
1422
1423 /* OK, it's launched! */
1424 pqAppendCmdQueueEntry(conn, entry);
1425 return 1;
1426
1427 sendFailed:
1428 pqRecycleCmdQueueEntry(conn, entry);
1429 /* error message should be set up already */
1430 return 0;
1431 }
1432
1433 /*
1434 * PQsendQueryParams
1435 * Like PQsendQuery, but use extended query protocol so we can pass parameters
1436 */
1437 int
PQsendQueryParams(PGconn * conn,const char * command,int nParams,const Oid * paramTypes,const char * const * paramValues,const int * paramLengths,const int * paramFormats,int resultFormat)1438 PQsendQueryParams(PGconn *conn,
1439 const char *command,
1440 int nParams,
1441 const Oid *paramTypes,
1442 const char *const *paramValues,
1443 const int *paramLengths,
1444 const int *paramFormats,
1445 int resultFormat)
1446 {
1447 if (!PQsendQueryStart(conn, true))
1448 return 0;
1449
1450 /* check the arguments */
1451 if (!command)
1452 {
1453 appendPQExpBufferStr(&conn->errorMessage,
1454 libpq_gettext("command string is a null pointer\n"));
1455 return 0;
1456 }
1457 if (nParams < 0 || nParams > PQ_QUERY_PARAM_MAX_LIMIT)
1458 {
1459 appendPQExpBuffer(&conn->errorMessage,
1460 libpq_gettext("number of parameters must be between 0 and %d\n"),
1461 PQ_QUERY_PARAM_MAX_LIMIT);
1462 return 0;
1463 }
1464
1465 return PQsendQueryGuts(conn,
1466 command,
1467 "", /* use unnamed statement */
1468 nParams,
1469 paramTypes,
1470 paramValues,
1471 paramLengths,
1472 paramFormats,
1473 resultFormat);
1474 }
1475
1476 /*
1477 * PQsendPrepare
1478 * Submit a Parse message, but don't wait for it to finish
1479 *
1480 * Returns: 1 if successfully submitted
1481 * 0 if error (conn->errorMessage is set)
1482 */
1483 int
PQsendPrepare(PGconn * conn,const char * stmtName,const char * query,int nParams,const Oid * paramTypes)1484 PQsendPrepare(PGconn *conn,
1485 const char *stmtName, const char *query,
1486 int nParams, const Oid *paramTypes)
1487 {
1488 PGcmdQueueEntry *entry = NULL;
1489
1490 if (!PQsendQueryStart(conn, true))
1491 return 0;
1492
1493 /* check the arguments */
1494 if (!stmtName)
1495 {
1496 appendPQExpBufferStr(&conn->errorMessage,
1497 libpq_gettext("statement name is a null pointer\n"));
1498 return 0;
1499 }
1500 if (!query)
1501 {
1502 appendPQExpBufferStr(&conn->errorMessage,
1503 libpq_gettext("command string is a null pointer\n"));
1504 return 0;
1505 }
1506 if (nParams < 0 || nParams > PQ_QUERY_PARAM_MAX_LIMIT)
1507 {
1508 appendPQExpBuffer(&conn->errorMessage,
1509 libpq_gettext("number of parameters must be between 0 and %d\n"),
1510 PQ_QUERY_PARAM_MAX_LIMIT);
1511 return 0;
1512 }
1513
1514 entry = pqAllocCmdQueueEntry(conn);
1515 if (entry == NULL)
1516 return 0; /* error msg already set */
1517
1518 /* construct the Parse message */
1519 if (pqPutMsgStart('P', conn) < 0 ||
1520 pqPuts(stmtName, conn) < 0 ||
1521 pqPuts(query, conn) < 0)
1522 goto sendFailed;
1523
1524 if (nParams > 0 && paramTypes)
1525 {
1526 int i;
1527
1528 if (pqPutInt(nParams, 2, conn) < 0)
1529 goto sendFailed;
1530 for (i = 0; i < nParams; i++)
1531 {
1532 if (pqPutInt(paramTypes[i], 4, conn) < 0)
1533 goto sendFailed;
1534 }
1535 }
1536 else
1537 {
1538 if (pqPutInt(0, 2, conn) < 0)
1539 goto sendFailed;
1540 }
1541 if (pqPutMsgEnd(conn) < 0)
1542 goto sendFailed;
1543
1544 /* Add a Sync, unless in pipeline mode. */
1545 if (conn->pipelineStatus == PQ_PIPELINE_OFF)
1546 {
1547 if (pqPutMsgStart('S', conn) < 0 ||
1548 pqPutMsgEnd(conn) < 0)
1549 goto sendFailed;
1550 }
1551
1552 /* remember we are doing just a Parse */
1553 entry->queryclass = PGQUERY_PREPARE;
1554
1555 /* and remember the query text too, if possible */
1556 /* if insufficient memory, query just winds up NULL */
1557 entry->query = strdup(query);
1558
1559 /*
1560 * Give the data a push (in pipeline mode, only if we're past the size
1561 * threshold). In nonblock mode, don't complain if we're unable to send
1562 * it all; PQgetResult() will do any additional flushing needed.
1563 */
1564 if (pqPipelineFlush(conn) < 0)
1565 goto sendFailed;
1566
1567 /* OK, it's launched! */
1568 pqAppendCmdQueueEntry(conn, entry);
1569
1570 return 1;
1571
1572 sendFailed:
1573 pqRecycleCmdQueueEntry(conn, entry);
1574 /* error message should be set up already */
1575 return 0;
1576 }
1577
1578 /*
1579 * PQsendQueryPrepared
1580 * Like PQsendQuery, but execute a previously prepared statement,
1581 * using extended query protocol so we can pass parameters
1582 */
1583 int
PQsendQueryPrepared(PGconn * conn,const char * stmtName,int nParams,const char * const * paramValues,const int * paramLengths,const int * paramFormats,int resultFormat)1584 PQsendQueryPrepared(PGconn *conn,
1585 const char *stmtName,
1586 int nParams,
1587 const char *const *paramValues,
1588 const int *paramLengths,
1589 const int *paramFormats,
1590 int resultFormat)
1591 {
1592 if (!PQsendQueryStart(conn, true))
1593 return 0;
1594
1595 /* check the arguments */
1596 if (!stmtName)
1597 {
1598 appendPQExpBufferStr(&conn->errorMessage,
1599 libpq_gettext("statement name is a null pointer\n"));
1600 return 0;
1601 }
1602 if (nParams < 0 || nParams > PQ_QUERY_PARAM_MAX_LIMIT)
1603 {
1604 appendPQExpBuffer(&conn->errorMessage,
1605 libpq_gettext("number of parameters must be between 0 and %d\n"),
1606 PQ_QUERY_PARAM_MAX_LIMIT);
1607 return 0;
1608 }
1609
1610 return PQsendQueryGuts(conn,
1611 NULL, /* no command to parse */
1612 stmtName,
1613 nParams,
1614 NULL, /* no param types */
1615 paramValues,
1616 paramLengths,
1617 paramFormats,
1618 resultFormat);
1619 }
1620
1621 /*
1622 * PQsendQueryStart
1623 * Common startup code for PQsendQuery and sibling routines
1624 */
1625 static bool
PQsendQueryStart(PGconn * conn,bool newQuery)1626 PQsendQueryStart(PGconn *conn, bool newQuery)
1627 {
1628 if (!conn)
1629 return false;
1630
1631 /*
1632 * If this is the beginning of a query cycle, reset the error buffer.
1633 */
1634 if (newQuery)
1635 resetPQExpBuffer(&conn->errorMessage);
1636
1637 /* Don't try to send if we know there's no live connection. */
1638 if (conn->status != CONNECTION_OK)
1639 {
1640 appendPQExpBufferStr(&conn->errorMessage,
1641 libpq_gettext("no connection to the server\n"));
1642 return false;
1643 }
1644
1645 /* Can't send while already busy, either, unless enqueuing for later */
1646 if (conn->asyncStatus != PGASYNC_IDLE &&
1647 conn->pipelineStatus == PQ_PIPELINE_OFF)
1648 {
1649 appendPQExpBufferStr(&conn->errorMessage,
1650 libpq_gettext("another command is already in progress\n"));
1651 return false;
1652 }
1653
1654 if (conn->pipelineStatus != PQ_PIPELINE_OFF)
1655 {
1656 /*
1657 * When enqueuing commands we don't change much of the connection
1658 * state since it's already in use for the current command. The
1659 * connection state will get updated when pqPipelineProcessQueue()
1660 * advances to start processing the queued message.
1661 *
1662 * Just make sure we can safely enqueue given the current connection
1663 * state. We can enqueue behind another queue item, or behind a
1664 * non-queue command (one that sends its own sync), but we can't
1665 * enqueue if the connection is in a copy state.
1666 */
1667 switch (conn->asyncStatus)
1668 {
1669 case PGASYNC_IDLE:
1670 case PGASYNC_READY:
1671 case PGASYNC_READY_MORE:
1672 case PGASYNC_BUSY:
1673 /* ok to queue */
1674 break;
1675 case PGASYNC_COPY_IN:
1676 case PGASYNC_COPY_OUT:
1677 case PGASYNC_COPY_BOTH:
1678 appendPQExpBufferStr(&conn->errorMessage,
1679 libpq_gettext("cannot queue commands during COPY\n"));
1680 return false;
1681 }
1682 }
1683 else
1684 {
1685 /*
1686 * This command's results will come in immediately. Initialize async
1687 * result-accumulation state
1688 */
1689 pqClearAsyncResult(conn);
1690
1691 /* reset single-row processing mode */
1692 conn->singleRowMode = false;
1693
1694 }
1695 /* ready to send command message */
1696 return true;
1697 }
1698
1699 /*
1700 * PQsendQueryGuts
1701 * Common code for sending a query with extended query protocol
1702 * PQsendQueryStart should be done already
1703 *
1704 * command may be NULL to indicate we use an already-prepared statement
1705 */
1706 static int
PQsendQueryGuts(PGconn * conn,const char * command,const char * stmtName,int nParams,const Oid * paramTypes,const char * const * paramValues,const int * paramLengths,const int * paramFormats,int resultFormat)1707 PQsendQueryGuts(PGconn *conn,
1708 const char *command,
1709 const char *stmtName,
1710 int nParams,
1711 const Oid *paramTypes,
1712 const char *const *paramValues,
1713 const int *paramLengths,
1714 const int *paramFormats,
1715 int resultFormat)
1716 {
1717 int i;
1718 PGcmdQueueEntry *entry;
1719
1720 entry = pqAllocCmdQueueEntry(conn);
1721 if (entry == NULL)
1722 return 0; /* error msg already set */
1723
1724 /*
1725 * We will send Parse (if needed), Bind, Describe Portal, Execute, Sync
1726 * (if not in pipeline mode), using specified statement name and the
1727 * unnamed portal.
1728 */
1729
1730 if (command)
1731 {
1732 /* construct the Parse message */
1733 if (pqPutMsgStart('P', conn) < 0 ||
1734 pqPuts(stmtName, conn) < 0 ||
1735 pqPuts(command, conn) < 0)
1736 goto sendFailed;
1737 if (nParams > 0 && paramTypes)
1738 {
1739 if (pqPutInt(nParams, 2, conn) < 0)
1740 goto sendFailed;
1741 for (i = 0; i < nParams; i++)
1742 {
1743 if (pqPutInt(paramTypes[i], 4, conn) < 0)
1744 goto sendFailed;
1745 }
1746 }
1747 else
1748 {
1749 if (pqPutInt(0, 2, conn) < 0)
1750 goto sendFailed;
1751 }
1752 if (pqPutMsgEnd(conn) < 0)
1753 goto sendFailed;
1754 }
1755
1756 /* Construct the Bind message */
1757 if (pqPutMsgStart('B', conn) < 0 ||
1758 pqPuts("", conn) < 0 ||
1759 pqPuts(stmtName, conn) < 0)
1760 goto sendFailed;
1761
1762 /* Send parameter formats */
1763 if (nParams > 0 && paramFormats)
1764 {
1765 if (pqPutInt(nParams, 2, conn) < 0)
1766 goto sendFailed;
1767 for (i = 0; i < nParams; i++)
1768 {
1769 if (pqPutInt(paramFormats[i], 2, conn) < 0)
1770 goto sendFailed;
1771 }
1772 }
1773 else
1774 {
1775 if (pqPutInt(0, 2, conn) < 0)
1776 goto sendFailed;
1777 }
1778
1779 if (pqPutInt(nParams, 2, conn) < 0)
1780 goto sendFailed;
1781
1782 /* Send parameters */
1783 for (i = 0; i < nParams; i++)
1784 {
1785 if (paramValues && paramValues[i])
1786 {
1787 int nbytes;
1788
1789 if (paramFormats && paramFormats[i] != 0)
1790 {
1791 /* binary parameter */
1792 if (paramLengths)
1793 nbytes = paramLengths[i];
1794 else
1795 {
1796 appendPQExpBufferStr(&conn->errorMessage,
1797 libpq_gettext("length must be given for binary parameter\n"));
1798 goto sendFailed;
1799 }
1800 }
1801 else
1802 {
1803 /* text parameter, do not use paramLengths */
1804 nbytes = strlen(paramValues[i]);
1805 }
1806 if (pqPutInt(nbytes, 4, conn) < 0 ||
1807 pqPutnchar(paramValues[i], nbytes, conn) < 0)
1808 goto sendFailed;
1809 }
1810 else
1811 {
1812 /* take the param as NULL */
1813 if (pqPutInt(-1, 4, conn) < 0)
1814 goto sendFailed;
1815 }
1816 }
1817 if (pqPutInt(1, 2, conn) < 0 ||
1818 pqPutInt(resultFormat, 2, conn))
1819 goto sendFailed;
1820 if (pqPutMsgEnd(conn) < 0)
1821 goto sendFailed;
1822
1823 /* construct the Describe Portal message */
1824 if (pqPutMsgStart('D', conn) < 0 ||
1825 pqPutc('P', conn) < 0 ||
1826 pqPuts("", conn) < 0 ||
1827 pqPutMsgEnd(conn) < 0)
1828 goto sendFailed;
1829
1830 /* construct the Execute message */
1831 if (pqPutMsgStart('E', conn) < 0 ||
1832 pqPuts("", conn) < 0 ||
1833 pqPutInt(0, 4, conn) < 0 ||
1834 pqPutMsgEnd(conn) < 0)
1835 goto sendFailed;
1836
1837 /* construct the Sync message if not in pipeline mode */
1838 if (conn->pipelineStatus == PQ_PIPELINE_OFF)
1839 {
1840 if (pqPutMsgStart('S', conn) < 0 ||
1841 pqPutMsgEnd(conn) < 0)
1842 goto sendFailed;
1843 }
1844
1845 /* remember we are using extended query protocol */
1846 entry->queryclass = PGQUERY_EXTENDED;
1847
1848 /* and remember the query text too, if possible */
1849 /* if insufficient memory, query just winds up NULL */
1850 if (command)
1851 entry->query = strdup(command);
1852
1853 /*
1854 * Give the data a push (in pipeline mode, only if we're past the size
1855 * threshold). In nonblock mode, don't complain if we're unable to send
1856 * it all; PQgetResult() will do any additional flushing needed.
1857 */
1858 if (pqPipelineFlush(conn) < 0)
1859 goto sendFailed;
1860
1861 /* OK, it's launched! */
1862 pqAppendCmdQueueEntry(conn, entry);
1863
1864 return 1;
1865
1866 sendFailed:
1867 pqRecycleCmdQueueEntry(conn, entry);
1868 /* error message should be set up already */
1869 return 0;
1870 }
1871
1872 /*
1873 * Select row-by-row processing mode
1874 */
1875 int
PQsetSingleRowMode(PGconn * conn)1876 PQsetSingleRowMode(PGconn *conn)
1877 {
1878 /*
1879 * Only allow setting the flag when we have launched a query and not yet
1880 * received any results.
1881 */
1882 if (!conn)
1883 return 0;
1884 if (conn->asyncStatus != PGASYNC_BUSY)
1885 return 0;
1886 if (!conn->cmd_queue_head ||
1887 (conn->cmd_queue_head->queryclass != PGQUERY_SIMPLE &&
1888 conn->cmd_queue_head->queryclass != PGQUERY_EXTENDED))
1889 return 0;
1890 if (conn->result)
1891 return 0;
1892
1893 /* OK, set flag */
1894 conn->singleRowMode = true;
1895 return 1;
1896 }
1897
1898 /*
1899 * Consume any available input from the backend
1900 * 0 return: some kind of trouble
1901 * 1 return: no problem
1902 */
1903 int
PQconsumeInput(PGconn * conn)1904 PQconsumeInput(PGconn *conn)
1905 {
1906 if (!conn)
1907 return 0;
1908
1909 /*
1910 * for non-blocking connections try to flush the send-queue, otherwise we
1911 * may never get a response for something that may not have already been
1912 * sent because it's in our write buffer!
1913 */
1914 if (pqIsnonblocking(conn))
1915 {
1916 if (pqFlush(conn) < 0)
1917 return 0;
1918 }
1919
1920 /*
1921 * Load more data, if available. We do this no matter what state we are
1922 * in, since we are probably getting called because the application wants
1923 * to get rid of a read-select condition. Note that we will NOT block
1924 * waiting for more input.
1925 */
1926 if (pqReadData(conn) < 0)
1927 return 0;
1928
1929 /* Parsing of the data waits till later. */
1930 return 1;
1931 }
1932
1933
1934 /*
1935 * parseInput: if appropriate, parse input data from backend
1936 * until input is exhausted or a stopping state is reached.
1937 * Note that this function will NOT attempt to read more data from the backend.
1938 */
1939 static void
parseInput(PGconn * conn)1940 parseInput(PGconn *conn)
1941 {
1942 pqParseInput3(conn);
1943 }
1944
1945 /*
1946 * PQisBusy
1947 * Return true if PQgetResult would block waiting for input.
1948 */
1949
1950 int
PQisBusy(PGconn * conn)1951 PQisBusy(PGconn *conn)
1952 {
1953 if (!conn)
1954 return false;
1955
1956 /* Parse any available data, if our state permits. */
1957 parseInput(conn);
1958
1959 /*
1960 * PQgetResult will return immediately in all states except BUSY, or if we
1961 * had a write failure.
1962 */
1963 return conn->asyncStatus == PGASYNC_BUSY || conn->write_failed;
1964 }
1965
1966 /*
1967 * PQgetResult
1968 * Get the next PGresult produced by a query. Returns NULL if no
1969 * query work remains or an error has occurred (e.g. out of
1970 * memory).
1971 *
1972 * In pipeline mode, once all the result of a query have been returned,
1973 * PQgetResult returns NULL to let the user know that the next
1974 * query is being processed. At the end of the pipeline, returns a
1975 * result with PQresultStatus(result) == PGRES_PIPELINE_SYNC.
1976 */
1977 PGresult *
PQgetResult(PGconn * conn)1978 PQgetResult(PGconn *conn)
1979 {
1980 PGresult *res;
1981
1982 if (!conn)
1983 return NULL;
1984
1985 /* Parse any available data, if our state permits. */
1986 parseInput(conn);
1987
1988 /* If not ready to return something, block until we are. */
1989 while (conn->asyncStatus == PGASYNC_BUSY)
1990 {
1991 int flushResult;
1992
1993 /*
1994 * If data remains unsent, send it. Else we might be waiting for the
1995 * result of a command the backend hasn't even got yet.
1996 */
1997 while ((flushResult = pqFlush(conn)) > 0)
1998 {
1999 if (pqWait(false, true, conn))
2000 {
2001 flushResult = -1;
2002 break;
2003 }
2004 }
2005
2006 /*
2007 * Wait for some more data, and load it. (Note: if the connection has
2008 * been lost, pqWait should return immediately because the socket
2009 * should be read-ready, either with the last server data or with an
2010 * EOF indication. We expect therefore that this won't result in any
2011 * undue delay in reporting a previous write failure.)
2012 */
2013 if (flushResult ||
2014 pqWait(true, false, conn) ||
2015 pqReadData(conn) < 0)
2016 {
2017 /*
2018 * conn->errorMessage has been set by pqWait or pqReadData. We
2019 * want to append it to any already-received error message.
2020 */
2021 pqSaveErrorResult(conn);
2022 conn->asyncStatus = PGASYNC_IDLE;
2023 return pqPrepareAsyncResult(conn);
2024 }
2025
2026 /* Parse it. */
2027 parseInput(conn);
2028
2029 /*
2030 * If we had a write error, but nothing above obtained a query result
2031 * or detected a read error, report the write error.
2032 */
2033 if (conn->write_failed && conn->asyncStatus == PGASYNC_BUSY)
2034 {
2035 pqSaveWriteError(conn);
2036 conn->asyncStatus = PGASYNC_IDLE;
2037 return pqPrepareAsyncResult(conn);
2038 }
2039 }
2040
2041 /* Return the appropriate thing. */
2042 switch (conn->asyncStatus)
2043 {
2044 case PGASYNC_IDLE:
2045 res = NULL; /* query is complete */
2046 if (conn->pipelineStatus != PQ_PIPELINE_OFF)
2047 {
2048 /*
2049 * We're about to return the NULL that terminates the round of
2050 * results from the current query; prepare to send the results
2051 * of the next query when we're called next. Also, since this
2052 * is the start of the results of the next query, clear any
2053 * prior error message.
2054 */
2055 resetPQExpBuffer(&conn->errorMessage);
2056 pqPipelineProcessQueue(conn);
2057 }
2058 break;
2059 case PGASYNC_READY:
2060
2061 /*
2062 * For any query type other than simple query protocol, we advance
2063 * the command queue here. This is because for simple query
2064 * protocol we can get the READY state multiple times before the
2065 * command is actually complete, since the command string can
2066 * contain many queries. In simple query protocol, the queue
2067 * advance is done by fe-protocol3 when it receives ReadyForQuery.
2068 */
2069 if (conn->cmd_queue_head &&
2070 conn->cmd_queue_head->queryclass != PGQUERY_SIMPLE)
2071 pqCommandQueueAdvance(conn);
2072 res = pqPrepareAsyncResult(conn);
2073 if (conn->pipelineStatus != PQ_PIPELINE_OFF)
2074 {
2075 /*
2076 * We're about to send the results of the current query. Set
2077 * us idle now, and ...
2078 */
2079 conn->asyncStatus = PGASYNC_IDLE;
2080
2081 /*
2082 * ... in cases when we're sending a pipeline-sync result,
2083 * move queue processing forwards immediately, so that next
2084 * time we're called, we're prepared to return the next result
2085 * received from the server. In all other cases, leave the
2086 * queue state change for next time, so that a terminating
2087 * NULL result is sent.
2088 *
2089 * (In other words: we don't return a NULL after a pipeline
2090 * sync.)
2091 */
2092 if (res && res->resultStatus == PGRES_PIPELINE_SYNC)
2093 pqPipelineProcessQueue(conn);
2094 }
2095 else
2096 {
2097 /* Set the state back to BUSY, allowing parsing to proceed. */
2098 conn->asyncStatus = PGASYNC_BUSY;
2099 }
2100 break;
2101 case PGASYNC_READY_MORE:
2102 res = pqPrepareAsyncResult(conn);
2103 /* Set the state back to BUSY, allowing parsing to proceed. */
2104 conn->asyncStatus = PGASYNC_BUSY;
2105 break;
2106 case PGASYNC_COPY_IN:
2107 res = getCopyResult(conn, PGRES_COPY_IN);
2108 break;
2109 case PGASYNC_COPY_OUT:
2110 res = getCopyResult(conn, PGRES_COPY_OUT);
2111 break;
2112 case PGASYNC_COPY_BOTH:
2113 res = getCopyResult(conn, PGRES_COPY_BOTH);
2114 break;
2115 default:
2116 appendPQExpBuffer(&conn->errorMessage,
2117 libpq_gettext("unexpected asyncStatus: %d\n"),
2118 (int) conn->asyncStatus);
2119 res = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
2120 break;
2121 }
2122
2123 if (res)
2124 {
2125 int i;
2126
2127 for (i = 0; i < res->nEvents; i++)
2128 {
2129 PGEventResultCreate evt;
2130
2131 evt.conn = conn;
2132 evt.result = res;
2133 if (!res->events[i].proc(PGEVT_RESULTCREATE, &evt,
2134 res->events[i].passThrough))
2135 {
2136 appendPQExpBuffer(&conn->errorMessage,
2137 libpq_gettext("PGEventProc \"%s\" failed during PGEVT_RESULTCREATE event\n"),
2138 res->events[i].name);
2139 pqSetResultError(res, &conn->errorMessage);
2140 res->resultStatus = PGRES_FATAL_ERROR;
2141 break;
2142 }
2143 res->events[i].resultInitialized = true;
2144 }
2145 }
2146
2147 return res;
2148 }
2149
2150 /*
2151 * getCopyResult
2152 * Helper for PQgetResult: generate result for COPY-in-progress cases
2153 */
2154 static PGresult *
getCopyResult(PGconn * conn,ExecStatusType copytype)2155 getCopyResult(PGconn *conn, ExecStatusType copytype)
2156 {
2157 /*
2158 * If the server connection has been lost, don't pretend everything is
2159 * hunky-dory; instead return a PGRES_FATAL_ERROR result, and reset the
2160 * asyncStatus to idle (corresponding to what we'd do if we'd detected I/O
2161 * error in the earlier steps in PQgetResult). The text returned in the
2162 * result is whatever is in conn->errorMessage; we hope that was filled
2163 * with something relevant when the lost connection was detected.
2164 */
2165 if (conn->status != CONNECTION_OK)
2166 {
2167 pqSaveErrorResult(conn);
2168 conn->asyncStatus = PGASYNC_IDLE;
2169 return pqPrepareAsyncResult(conn);
2170 }
2171
2172 /* If we have an async result for the COPY, return that */
2173 if (conn->result && conn->result->resultStatus == copytype)
2174 return pqPrepareAsyncResult(conn);
2175
2176 /* Otherwise, invent a suitable PGresult */
2177 return PQmakeEmptyPGresult(conn, copytype);
2178 }
2179
2180
2181 /*
2182 * PQexec
2183 * send a query to the backend and package up the result in a PGresult
2184 *
2185 * If the query was not even sent, return NULL; conn->errorMessage is set to
2186 * a relevant message.
2187 * If the query was sent, a new PGresult is returned (which could indicate
2188 * either success or failure).
2189 * The user is responsible for freeing the PGresult via PQclear()
2190 * when done with it.
2191 */
2192 PGresult *
PQexec(PGconn * conn,const char * query)2193 PQexec(PGconn *conn, const char *query)
2194 {
2195 if (!PQexecStart(conn))
2196 return NULL;
2197 if (!PQsendQuery(conn, query))
2198 return NULL;
2199 return PQexecFinish(conn);
2200 }
2201
2202 /*
2203 * PQexecParams
2204 * Like PQexec, but use extended query protocol so we can pass parameters
2205 */
2206 PGresult *
PQexecParams(PGconn * conn,const char * command,int nParams,const Oid * paramTypes,const char * const * paramValues,const int * paramLengths,const int * paramFormats,int resultFormat)2207 PQexecParams(PGconn *conn,
2208 const char *command,
2209 int nParams,
2210 const Oid *paramTypes,
2211 const char *const *paramValues,
2212 const int *paramLengths,
2213 const int *paramFormats,
2214 int resultFormat)
2215 {
2216 if (!PQexecStart(conn))
2217 return NULL;
2218 if (!PQsendQueryParams(conn, command,
2219 nParams, paramTypes, paramValues, paramLengths,
2220 paramFormats, resultFormat))
2221 return NULL;
2222 return PQexecFinish(conn);
2223 }
2224
2225 /*
2226 * PQprepare
2227 * Creates a prepared statement by issuing a Parse message.
2228 *
2229 * If the query was not even sent, return NULL; conn->errorMessage is set to
2230 * a relevant message.
2231 * If the query was sent, a new PGresult is returned (which could indicate
2232 * either success or failure).
2233 * The user is responsible for freeing the PGresult via PQclear()
2234 * when done with it.
2235 */
2236 PGresult *
PQprepare(PGconn * conn,const char * stmtName,const char * query,int nParams,const Oid * paramTypes)2237 PQprepare(PGconn *conn,
2238 const char *stmtName, const char *query,
2239 int nParams, const Oid *paramTypes)
2240 {
2241 if (!PQexecStart(conn))
2242 return NULL;
2243 if (!PQsendPrepare(conn, stmtName, query, nParams, paramTypes))
2244 return NULL;
2245 return PQexecFinish(conn);
2246 }
2247
2248 /*
2249 * PQexecPrepared
2250 * Like PQexec, but execute a previously prepared statement,
2251 * using extended query protocol so we can pass parameters
2252 */
2253 PGresult *
PQexecPrepared(PGconn * conn,const char * stmtName,int nParams,const char * const * paramValues,const int * paramLengths,const int * paramFormats,int resultFormat)2254 PQexecPrepared(PGconn *conn,
2255 const char *stmtName,
2256 int nParams,
2257 const char *const *paramValues,
2258 const int *paramLengths,
2259 const int *paramFormats,
2260 int resultFormat)
2261 {
2262 if (!PQexecStart(conn))
2263 return NULL;
2264 if (!PQsendQueryPrepared(conn, stmtName,
2265 nParams, paramValues, paramLengths,
2266 paramFormats, resultFormat))
2267 return NULL;
2268 return PQexecFinish(conn);
2269 }
2270
2271 /*
2272 * Common code for PQexec and sibling routines: prepare to send command
2273 */
2274 static bool
PQexecStart(PGconn * conn)2275 PQexecStart(PGconn *conn)
2276 {
2277 PGresult *result;
2278
2279 if (!conn)
2280 return false;
2281
2282 if (conn->pipelineStatus != PQ_PIPELINE_OFF)
2283 {
2284 appendPQExpBufferStr(&conn->errorMessage,
2285 libpq_gettext("synchronous command execution functions are not allowed in pipeline mode\n"));
2286 return false;
2287 }
2288
2289 /*
2290 * Since this is the beginning of a query cycle, reset the error buffer.
2291 */
2292 resetPQExpBuffer(&conn->errorMessage);
2293
2294 /*
2295 * Silently discard any prior query result that application didn't eat.
2296 * This is probably poor design, but it's here for backward compatibility.
2297 */
2298 while ((result = PQgetResult(conn)) != NULL)
2299 {
2300 ExecStatusType resultStatus = result->resultStatus;
2301
2302 PQclear(result); /* only need its status */
2303 if (resultStatus == PGRES_COPY_IN)
2304 {
2305 /* get out of a COPY IN state */
2306 if (PQputCopyEnd(conn,
2307 libpq_gettext("COPY terminated by new PQexec")) < 0)
2308 return false;
2309 /* keep waiting to swallow the copy's failure message */
2310 }
2311 else if (resultStatus == PGRES_COPY_OUT)
2312 {
2313 /*
2314 * Get out of a COPY OUT state: we just switch back to BUSY and
2315 * allow the remaining COPY data to be dropped on the floor.
2316 */
2317 conn->asyncStatus = PGASYNC_BUSY;
2318 /* keep waiting to swallow the copy's completion message */
2319 }
2320 else if (resultStatus == PGRES_COPY_BOTH)
2321 {
2322 /* We don't allow PQexec during COPY BOTH */
2323 appendPQExpBufferStr(&conn->errorMessage,
2324 libpq_gettext("PQexec not allowed during COPY BOTH\n"));
2325 return false;
2326 }
2327 /* check for loss of connection, too */
2328 if (conn->status == CONNECTION_BAD)
2329 return false;
2330 }
2331
2332 /* OK to send a command */
2333 return true;
2334 }
2335
2336 /*
2337 * Common code for PQexec and sibling routines: wait for command result
2338 */
2339 static PGresult *
PQexecFinish(PGconn * conn)2340 PQexecFinish(PGconn *conn)
2341 {
2342 PGresult *result;
2343 PGresult *lastResult;
2344
2345 /*
2346 * For backwards compatibility, return the last result if there are more
2347 * than one. (We used to have logic here to concatenate successive error
2348 * messages, but now that happens automatically, since conn->errorMessage
2349 * will continue to accumulate errors throughout this loop.)
2350 *
2351 * We have to stop if we see copy in/out/both, however. We will resume
2352 * parsing after application performs the data transfer.
2353 *
2354 * Also stop if the connection is lost (else we'll loop infinitely).
2355 */
2356 lastResult = NULL;
2357 while ((result = PQgetResult(conn)) != NULL)
2358 {
2359 if (lastResult)
2360 PQclear(lastResult);
2361 lastResult = result;
2362 if (result->resultStatus == PGRES_COPY_IN ||
2363 result->resultStatus == PGRES_COPY_OUT ||
2364 result->resultStatus == PGRES_COPY_BOTH ||
2365 conn->status == CONNECTION_BAD)
2366 break;
2367 }
2368
2369 return lastResult;
2370 }
2371
2372 /*
2373 * PQdescribePrepared
2374 * Obtain information about a previously prepared statement
2375 *
2376 * If the query was not even sent, return NULL; conn->errorMessage is set to
2377 * a relevant message.
2378 * If the query was sent, a new PGresult is returned (which could indicate
2379 * either success or failure). On success, the PGresult contains status
2380 * PGRES_COMMAND_OK, and its parameter and column-heading fields describe
2381 * the statement's inputs and outputs respectively.
2382 * The user is responsible for freeing the PGresult via PQclear()
2383 * when done with it.
2384 */
2385 PGresult *
PQdescribePrepared(PGconn * conn,const char * stmt)2386 PQdescribePrepared(PGconn *conn, const char *stmt)
2387 {
2388 if (!PQexecStart(conn))
2389 return NULL;
2390 if (!PQsendDescribe(conn, 'S', stmt))
2391 return NULL;
2392 return PQexecFinish(conn);
2393 }
2394
2395 /*
2396 * PQdescribePortal
2397 * Obtain information about a previously created portal
2398 *
2399 * This is much like PQdescribePrepared, except that no parameter info is
2400 * returned. Note that at the moment, libpq doesn't really expose portals
2401 * to the client; but this can be used with a portal created by a SQL
2402 * DECLARE CURSOR command.
2403 */
2404 PGresult *
PQdescribePortal(PGconn * conn,const char * portal)2405 PQdescribePortal(PGconn *conn, const char *portal)
2406 {
2407 if (!PQexecStart(conn))
2408 return NULL;
2409 if (!PQsendDescribe(conn, 'P', portal))
2410 return NULL;
2411 return PQexecFinish(conn);
2412 }
2413
2414 /*
2415 * PQsendDescribePrepared
2416 * Submit a Describe Statement command, but don't wait for it to finish
2417 *
2418 * Returns: 1 if successfully submitted
2419 * 0 if error (conn->errorMessage is set)
2420 */
2421 int
PQsendDescribePrepared(PGconn * conn,const char * stmt)2422 PQsendDescribePrepared(PGconn *conn, const char *stmt)
2423 {
2424 return PQsendDescribe(conn, 'S', stmt);
2425 }
2426
2427 /*
2428 * PQsendDescribePortal
2429 * Submit a Describe Portal command, but don't wait for it to finish
2430 *
2431 * Returns: 1 if successfully submitted
2432 * 0 if error (conn->errorMessage is set)
2433 */
2434 int
PQsendDescribePortal(PGconn * conn,const char * portal)2435 PQsendDescribePortal(PGconn *conn, const char *portal)
2436 {
2437 return PQsendDescribe(conn, 'P', portal);
2438 }
2439
2440 /*
2441 * PQsendDescribe
2442 * Common code to send a Describe command
2443 *
2444 * Available options for desc_type are
2445 * 'S' to describe a prepared statement; or
2446 * 'P' to describe a portal.
2447 * Returns 1 on success and 0 on failure.
2448 */
2449 static int
PQsendDescribe(PGconn * conn,char desc_type,const char * desc_target)2450 PQsendDescribe(PGconn *conn, char desc_type, const char *desc_target)
2451 {
2452 PGcmdQueueEntry *entry = NULL;
2453
2454 /* Treat null desc_target as empty string */
2455 if (!desc_target)
2456 desc_target = "";
2457
2458 if (!PQsendQueryStart(conn, true))
2459 return 0;
2460
2461 entry = pqAllocCmdQueueEntry(conn);
2462 if (entry == NULL)
2463 return 0; /* error msg already set */
2464
2465 /* construct the Describe message */
2466 if (pqPutMsgStart('D', conn) < 0 ||
2467 pqPutc(desc_type, conn) < 0 ||
2468 pqPuts(desc_target, conn) < 0 ||
2469 pqPutMsgEnd(conn) < 0)
2470 goto sendFailed;
2471
2472 /* construct the Sync message */
2473 if (conn->pipelineStatus == PQ_PIPELINE_OFF)
2474 {
2475 if (pqPutMsgStart('S', conn) < 0 ||
2476 pqPutMsgEnd(conn) < 0)
2477 goto sendFailed;
2478 }
2479
2480 /* remember we are doing a Describe */
2481 entry->queryclass = PGQUERY_DESCRIBE;
2482
2483 /*
2484 * Give the data a push (in pipeline mode, only if we're past the size
2485 * threshold). In nonblock mode, don't complain if we're unable to send
2486 * it all; PQgetResult() will do any additional flushing needed.
2487 */
2488 if (pqPipelineFlush(conn) < 0)
2489 goto sendFailed;
2490
2491 /* OK, it's launched! */
2492 pqAppendCmdQueueEntry(conn, entry);
2493
2494 return 1;
2495
2496 sendFailed:
2497 pqRecycleCmdQueueEntry(conn, entry);
2498 /* error message should be set up already */
2499 return 0;
2500 }
2501
2502 /*
2503 * PQnotifies
2504 * returns a PGnotify* structure of the latest async notification
2505 * that has not yet been handled
2506 *
2507 * returns NULL, if there is currently
2508 * no unhandled async notification from the backend
2509 *
2510 * the CALLER is responsible for FREE'ing the structure returned
2511 *
2512 * Note that this function does not read any new data from the socket;
2513 * so usually, caller should call PQconsumeInput() first.
2514 */
2515 PGnotify *
PQnotifies(PGconn * conn)2516 PQnotifies(PGconn *conn)
2517 {
2518 PGnotify *event;
2519
2520 if (!conn)
2521 return NULL;
2522
2523 /* Parse any available data to see if we can extract NOTIFY messages. */
2524 parseInput(conn);
2525
2526 event = conn->notifyHead;
2527 if (event)
2528 {
2529 conn->notifyHead = event->next;
2530 if (!conn->notifyHead)
2531 conn->notifyTail = NULL;
2532 event->next = NULL; /* don't let app see the internal state */
2533 }
2534 return event;
2535 }
2536
2537 /*
2538 * PQputCopyData - send some data to the backend during COPY IN or COPY BOTH
2539 *
2540 * Returns 1 if successful, 0 if data could not be sent (only possible
2541 * in nonblock mode), or -1 if an error occurs.
2542 */
2543 int
PQputCopyData(PGconn * conn,const char * buffer,int nbytes)2544 PQputCopyData(PGconn *conn, const char *buffer, int nbytes)
2545 {
2546 if (!conn)
2547 return -1;
2548 if (conn->asyncStatus != PGASYNC_COPY_IN &&
2549 conn->asyncStatus != PGASYNC_COPY_BOTH)
2550 {
2551 appendPQExpBufferStr(&conn->errorMessage,
2552 libpq_gettext("no COPY in progress\n"));
2553 return -1;
2554 }
2555
2556 /*
2557 * Process any NOTICE or NOTIFY messages that might be pending in the
2558 * input buffer. Since the server might generate many notices during the
2559 * COPY, we want to clean those out reasonably promptly to prevent
2560 * indefinite expansion of the input buffer. (Note: the actual read of
2561 * input data into the input buffer happens down inside pqSendSome, but
2562 * it's not authorized to get rid of the data again.)
2563 */
2564 parseInput(conn);
2565
2566 if (nbytes > 0)
2567 {
2568 /*
2569 * Try to flush any previously sent data in preference to growing the
2570 * output buffer. If we can't enlarge the buffer enough to hold the
2571 * data, return 0 in the nonblock case, else hard error. (For
2572 * simplicity, always assume 5 bytes of overhead.)
2573 */
2574 if ((conn->outBufSize - conn->outCount - 5) < nbytes)
2575 {
2576 if (pqFlush(conn) < 0)
2577 return -1;
2578 if (pqCheckOutBufferSpace(conn->outCount + 5 + (size_t) nbytes,
2579 conn))
2580 return pqIsnonblocking(conn) ? 0 : -1;
2581 }
2582 /* Send the data (too simple to delegate to fe-protocol files) */
2583 if (pqPutMsgStart('d', conn) < 0 ||
2584 pqPutnchar(buffer, nbytes, conn) < 0 ||
2585 pqPutMsgEnd(conn) < 0)
2586 return -1;
2587 }
2588 return 1;
2589 }
2590
2591 /*
2592 * PQputCopyEnd - send EOF indication to the backend during COPY IN
2593 *
2594 * After calling this, use PQgetResult() to check command completion status.
2595 *
2596 * Returns 1 if successful, 0 if data could not be sent (only possible
2597 * in nonblock mode), or -1 if an error occurs.
2598 */
2599 int
PQputCopyEnd(PGconn * conn,const char * errormsg)2600 PQputCopyEnd(PGconn *conn, const char *errormsg)
2601 {
2602 if (!conn)
2603 return -1;
2604 if (conn->asyncStatus != PGASYNC_COPY_IN &&
2605 conn->asyncStatus != PGASYNC_COPY_BOTH)
2606 {
2607 appendPQExpBufferStr(&conn->errorMessage,
2608 libpq_gettext("no COPY in progress\n"));
2609 return -1;
2610 }
2611
2612 /*
2613 * Send the COPY END indicator. This is simple enough that we don't
2614 * bother delegating it to the fe-protocol files.
2615 */
2616 if (errormsg)
2617 {
2618 /* Send COPY FAIL */
2619 if (pqPutMsgStart('f', conn) < 0 ||
2620 pqPuts(errormsg, conn) < 0 ||
2621 pqPutMsgEnd(conn) < 0)
2622 return -1;
2623 }
2624 else
2625 {
2626 /* Send COPY DONE */
2627 if (pqPutMsgStart('c', conn) < 0 ||
2628 pqPutMsgEnd(conn) < 0)
2629 return -1;
2630 }
2631
2632 /*
2633 * If we sent the COPY command in extended-query mode, we must issue a
2634 * Sync as well.
2635 */
2636 if (conn->cmd_queue_head &&
2637 conn->cmd_queue_head->queryclass != PGQUERY_SIMPLE)
2638 {
2639 if (pqPutMsgStart('S', conn) < 0 ||
2640 pqPutMsgEnd(conn) < 0)
2641 return -1;
2642 }
2643
2644 /* Return to active duty */
2645 if (conn->asyncStatus == PGASYNC_COPY_BOTH)
2646 conn->asyncStatus = PGASYNC_COPY_OUT;
2647 else
2648 conn->asyncStatus = PGASYNC_BUSY;
2649
2650 /* Try to flush data */
2651 if (pqFlush(conn) < 0)
2652 return -1;
2653
2654 return 1;
2655 }
2656
2657 /*
2658 * PQgetCopyData - read a row of data from the backend during COPY OUT
2659 * or COPY BOTH
2660 *
2661 * If successful, sets *buffer to point to a malloc'd row of data, and
2662 * returns row length (always > 0) as result.
2663 * Returns 0 if no row available yet (only possible if async is true),
2664 * -1 if end of copy (consult PQgetResult), or -2 if error (consult
2665 * PQerrorMessage).
2666 */
2667 int
PQgetCopyData(PGconn * conn,char ** buffer,int async)2668 PQgetCopyData(PGconn *conn, char **buffer, int async)
2669 {
2670 *buffer = NULL; /* for all failure cases */
2671 if (!conn)
2672 return -2;
2673 if (conn->asyncStatus != PGASYNC_COPY_OUT &&
2674 conn->asyncStatus != PGASYNC_COPY_BOTH)
2675 {
2676 appendPQExpBufferStr(&conn->errorMessage,
2677 libpq_gettext("no COPY in progress\n"));
2678 return -2;
2679 }
2680 return pqGetCopyData3(conn, buffer, async);
2681 }
2682
2683 /*
2684 * PQgetline - gets a newline-terminated string from the backend.
2685 *
2686 * Chiefly here so that applications can use "COPY <rel> to stdout"
2687 * and read the output string. Returns a null-terminated string in s.
2688 *
2689 * XXX this routine is now deprecated, because it can't handle binary data.
2690 * If called during a COPY BINARY we return EOF.
2691 *
2692 * PQgetline reads up to maxlen-1 characters (like fgets(3)) but strips
2693 * the terminating \n (like gets(3)).
2694 *
2695 * CAUTION: the caller is responsible for detecting the end-of-copy signal
2696 * (a line containing just "\.") when using this routine.
2697 *
2698 * RETURNS:
2699 * EOF if error (eg, invalid arguments are given)
2700 * 0 if EOL is reached (i.e., \n has been read)
2701 * (this is required for backward-compatibility -- this
2702 * routine used to always return EOF or 0, assuming that
2703 * the line ended within maxlen bytes.)
2704 * 1 in other cases (i.e., the buffer was filled before \n is reached)
2705 */
2706 int
PQgetline(PGconn * conn,char * s,int maxlen)2707 PQgetline(PGconn *conn, char *s, int maxlen)
2708 {
2709 if (!s || maxlen <= 0)
2710 return EOF;
2711 *s = '\0';
2712 /* maxlen must be at least 3 to hold the \. terminator! */
2713 if (maxlen < 3)
2714 return EOF;
2715
2716 if (!conn)
2717 return EOF;
2718
2719 return pqGetline3(conn, s, maxlen);
2720 }
2721
2722 /*
2723 * PQgetlineAsync - gets a COPY data row without blocking.
2724 *
2725 * This routine is for applications that want to do "COPY <rel> to stdout"
2726 * asynchronously, that is without blocking. Having issued the COPY command
2727 * and gotten a PGRES_COPY_OUT response, the app should call PQconsumeInput
2728 * and this routine until the end-of-data signal is detected. Unlike
2729 * PQgetline, this routine takes responsibility for detecting end-of-data.
2730 *
2731 * On each call, PQgetlineAsync will return data if a complete data row
2732 * is available in libpq's input buffer. Otherwise, no data is returned
2733 * until the rest of the row arrives.
2734 *
2735 * If -1 is returned, the end-of-data signal has been recognized (and removed
2736 * from libpq's input buffer). The caller *must* next call PQendcopy and
2737 * then return to normal processing.
2738 *
2739 * RETURNS:
2740 * -1 if the end-of-copy-data marker has been recognized
2741 * 0 if no data is available
2742 * >0 the number of bytes returned.
2743 *
2744 * The data returned will not extend beyond a data-row boundary. If possible
2745 * a whole row will be returned at one time. But if the buffer offered by
2746 * the caller is too small to hold a row sent by the backend, then a partial
2747 * data row will be returned. In text mode this can be detected by testing
2748 * whether the last returned byte is '\n' or not.
2749 *
2750 * The returned data is *not* null-terminated.
2751 */
2752
2753 int
PQgetlineAsync(PGconn * conn,char * buffer,int bufsize)2754 PQgetlineAsync(PGconn *conn, char *buffer, int bufsize)
2755 {
2756 if (!conn)
2757 return -1;
2758
2759 return pqGetlineAsync3(conn, buffer, bufsize);
2760 }
2761
2762 /*
2763 * PQputline -- sends a string to the backend during COPY IN.
2764 * Returns 0 if OK, EOF if not.
2765 *
2766 * This is deprecated primarily because the return convention doesn't allow
2767 * caller to tell the difference between a hard error and a nonblock-mode
2768 * send failure.
2769 */
2770 int
PQputline(PGconn * conn,const char * s)2771 PQputline(PGconn *conn, const char *s)
2772 {
2773 return PQputnbytes(conn, s, strlen(s));
2774 }
2775
2776 /*
2777 * PQputnbytes -- like PQputline, but buffer need not be null-terminated.
2778 * Returns 0 if OK, EOF if not.
2779 */
2780 int
PQputnbytes(PGconn * conn,const char * buffer,int nbytes)2781 PQputnbytes(PGconn *conn, const char *buffer, int nbytes)
2782 {
2783 if (PQputCopyData(conn, buffer, nbytes) > 0)
2784 return 0;
2785 else
2786 return EOF;
2787 }
2788
2789 /*
2790 * PQendcopy
2791 * After completing the data transfer portion of a copy in/out,
2792 * the application must call this routine to finish the command protocol.
2793 *
2794 * This is deprecated; it's cleaner to use PQgetResult to get the transfer
2795 * status.
2796 *
2797 * RETURNS:
2798 * 0 on success
2799 * 1 on failure
2800 */
2801 int
PQendcopy(PGconn * conn)2802 PQendcopy(PGconn *conn)
2803 {
2804 if (!conn)
2805 return 0;
2806
2807 return pqEndcopy3(conn);
2808 }
2809
2810
2811 /* ----------------
2812 * PQfn - Send a function call to the POSTGRES backend.
2813 *
2814 * conn : backend connection
2815 * fnid : OID of function to be called
2816 * result_buf : pointer to result buffer
2817 * result_len : actual length of result is returned here
2818 * result_is_int : If the result is an integer, this must be 1,
2819 * otherwise this should be 0
2820 * args : pointer to an array of function arguments
2821 * (each has length, if integer, and value/pointer)
2822 * nargs : # of arguments in args array.
2823 *
2824 * RETURNS
2825 * PGresult with status = PGRES_COMMAND_OK if successful.
2826 * *result_len is > 0 if there is a return value, 0 if not.
2827 * PGresult with status = PGRES_FATAL_ERROR if backend returns an error.
2828 * NULL on communications failure. conn->errorMessage will be set.
2829 * ----------------
2830 */
2831
2832 PGresult *
PQfn(PGconn * conn,int fnid,int * result_buf,int * result_len,int result_is_int,const PQArgBlock * args,int nargs)2833 PQfn(PGconn *conn,
2834 int fnid,
2835 int *result_buf,
2836 int *result_len,
2837 int result_is_int,
2838 const PQArgBlock *args,
2839 int nargs)
2840 {
2841 *result_len = 0;
2842
2843 if (!conn)
2844 return NULL;
2845
2846 /*
2847 * Since this is the beginning of a query cycle, reset the error buffer.
2848 */
2849 resetPQExpBuffer(&conn->errorMessage);
2850
2851 if (conn->pipelineStatus != PQ_PIPELINE_OFF)
2852 {
2853 appendPQExpBufferStr(&conn->errorMessage,
2854 libpq_gettext("PQfn not allowed in pipeline mode\n"));
2855 return NULL;
2856 }
2857
2858 if (conn->sock == PGINVALID_SOCKET || conn->asyncStatus != PGASYNC_IDLE ||
2859 conn->result != NULL)
2860 {
2861 appendPQExpBufferStr(&conn->errorMessage,
2862 libpq_gettext("connection in wrong state\n"));
2863 return NULL;
2864 }
2865
2866 return pqFunctionCall3(conn, fnid,
2867 result_buf, result_len,
2868 result_is_int,
2869 args, nargs);
2870 }
2871
2872 /* ====== Pipeline mode support ======== */
2873
2874 /*
2875 * PQenterPipelineMode
2876 * Put an idle connection in pipeline mode.
2877 *
2878 * Returns 1 on success. On failure, errorMessage is set and 0 is returned.
2879 *
2880 * Commands submitted after this can be pipelined on the connection;
2881 * there's no requirement to wait for one to finish before the next is
2882 * dispatched.
2883 *
2884 * Queuing of a new query or syncing during COPY is not allowed.
2885 *
2886 * A set of commands is terminated by a PQpipelineSync. Multiple sync
2887 * points can be established while in pipeline mode. Pipeline mode can
2888 * be exited by calling PQexitPipelineMode() once all results are processed.
2889 *
2890 * This doesn't actually send anything on the wire, it just puts libpq
2891 * into a state where it can pipeline work.
2892 */
2893 int
PQenterPipelineMode(PGconn * conn)2894 PQenterPipelineMode(PGconn *conn)
2895 {
2896 if (!conn)
2897 return 0;
2898
2899 /* succeed with no action if already in pipeline mode */
2900 if (conn->pipelineStatus != PQ_PIPELINE_OFF)
2901 return 1;
2902
2903 if (conn->asyncStatus != PGASYNC_IDLE)
2904 {
2905 appendPQExpBufferStr(&conn->errorMessage,
2906 libpq_gettext("cannot enter pipeline mode, connection not idle\n"));
2907 return 0;
2908 }
2909
2910 conn->pipelineStatus = PQ_PIPELINE_ON;
2911
2912 return 1;
2913 }
2914
2915 /*
2916 * PQexitPipelineMode
2917 * End pipeline mode and return to normal command mode.
2918 *
2919 * Returns 1 in success (pipeline mode successfully ended, or not in pipeline
2920 * mode).
2921 *
2922 * Returns 0 if in pipeline mode and cannot be ended yet. Error message will
2923 * be set.
2924 */
2925 int
PQexitPipelineMode(PGconn * conn)2926 PQexitPipelineMode(PGconn *conn)
2927 {
2928 if (!conn)
2929 return 0;
2930
2931 if (conn->pipelineStatus == PQ_PIPELINE_OFF)
2932 return 1;
2933
2934 switch (conn->asyncStatus)
2935 {
2936 case PGASYNC_READY:
2937 case PGASYNC_READY_MORE:
2938 /* there are some uncollected results */
2939 appendPQExpBufferStr(&conn->errorMessage,
2940 libpq_gettext("cannot exit pipeline mode with uncollected results\n"));
2941 return 0;
2942
2943 case PGASYNC_BUSY:
2944 appendPQExpBufferStr(&conn->errorMessage,
2945 libpq_gettext("cannot exit pipeline mode while busy\n"));
2946 return 0;
2947
2948 default:
2949 /* OK */
2950 break;
2951 }
2952
2953 /* still work to process */
2954 if (conn->cmd_queue_head != NULL)
2955 {
2956 appendPQExpBufferStr(&conn->errorMessage,
2957 libpq_gettext("cannot exit pipeline mode with uncollected results\n"));
2958 return 0;
2959 }
2960
2961 conn->pipelineStatus = PQ_PIPELINE_OFF;
2962 conn->asyncStatus = PGASYNC_IDLE;
2963
2964 /* Flush any pending data in out buffer */
2965 if (pqFlush(conn) < 0)
2966 return 0; /* error message is setup already */
2967 return 1;
2968 }
2969
2970 /*
2971 * pqCommandQueueAdvance
2972 * Remove one query from the command queue, when we receive
2973 * all results from the server that pertain to it.
2974 */
2975 void
pqCommandQueueAdvance(PGconn * conn)2976 pqCommandQueueAdvance(PGconn *conn)
2977 {
2978 PGcmdQueueEntry *prevquery;
2979
2980 if (conn->cmd_queue_head == NULL)
2981 return;
2982
2983 /* delink from queue */
2984 prevquery = conn->cmd_queue_head;
2985 conn->cmd_queue_head = conn->cmd_queue_head->next;
2986
2987 /* and make it recyclable */
2988 prevquery->next = NULL;
2989 pqRecycleCmdQueueEntry(conn, prevquery);
2990 }
2991
2992 /*
2993 * pqPipelineProcessQueue: subroutine for PQgetResult
2994 * In pipeline mode, start processing the results of the next query in the queue.
2995 */
2996 static void
pqPipelineProcessQueue(PGconn * conn)2997 pqPipelineProcessQueue(PGconn *conn)
2998 {
2999 switch (conn->asyncStatus)
3000 {
3001 case PGASYNC_COPY_IN:
3002 case PGASYNC_COPY_OUT:
3003 case PGASYNC_COPY_BOTH:
3004 case PGASYNC_READY:
3005 case PGASYNC_READY_MORE:
3006 case PGASYNC_BUSY:
3007 /* client still has to process current query or results */
3008 return;
3009 case PGASYNC_IDLE:
3010 /* next query please */
3011 break;
3012 }
3013
3014 /* Nothing to do if not in pipeline mode, or queue is empty */
3015 if (conn->pipelineStatus == PQ_PIPELINE_OFF ||
3016 conn->cmd_queue_head == NULL)
3017 return;
3018
3019 /* Initialize async result-accumulation state */
3020 pqClearAsyncResult(conn);
3021
3022 /*
3023 * Reset single-row processing mode. (Client has to set it up for each
3024 * query, if desired.)
3025 */
3026 conn->singleRowMode = false;
3027
3028 if (conn->pipelineStatus == PQ_PIPELINE_ABORTED &&
3029 conn->cmd_queue_head->queryclass != PGQUERY_SYNC)
3030 {
3031 /*
3032 * In an aborted pipeline we don't get anything from the server for
3033 * each result; we're just discarding commands from the queue until we
3034 * get to the next sync from the server.
3035 *
3036 * The PGRES_PIPELINE_ABORTED results tell the client that its queries
3037 * got aborted.
3038 */
3039 conn->result = PQmakeEmptyPGresult(conn, PGRES_PIPELINE_ABORTED);
3040 if (!conn->result)
3041 {
3042 appendPQExpBufferStr(&conn->errorMessage,
3043 libpq_gettext("out of memory\n"));
3044 pqSaveErrorResult(conn);
3045 return;
3046 }
3047 conn->asyncStatus = PGASYNC_READY;
3048 }
3049 else
3050 {
3051 /* allow parsing to continue */
3052 conn->asyncStatus = PGASYNC_BUSY;
3053 }
3054 }
3055
3056 /*
3057 * PQpipelineSync
3058 * Send a Sync message as part of a pipeline, and flush to server
3059 *
3060 * It's legal to start submitting more commands in the pipeline immediately,
3061 * without waiting for the results of the current pipeline. There's no need to
3062 * end pipeline mode and start it again.
3063 *
3064 * If a command in a pipeline fails, every subsequent command up to and including
3065 * the result to the Sync message sent by PQpipelineSync gets set to
3066 * PGRES_PIPELINE_ABORTED state. If the whole pipeline is processed without
3067 * error, a PGresult with PGRES_PIPELINE_SYNC is produced.
3068 *
3069 * Queries can already have been sent before PQpipelineSync is called, but
3070 * PQpipelineSync need to be called before retrieving command results.
3071 *
3072 * The connection will remain in pipeline mode and unavailable for new
3073 * synchronous command execution functions until all results from the pipeline
3074 * are processed by the client.
3075 */
3076 int
PQpipelineSync(PGconn * conn)3077 PQpipelineSync(PGconn *conn)
3078 {
3079 PGcmdQueueEntry *entry;
3080
3081 if (!conn)
3082 return 0;
3083
3084 if (conn->pipelineStatus == PQ_PIPELINE_OFF)
3085 {
3086 appendPQExpBufferStr(&conn->errorMessage,
3087 libpq_gettext("cannot send pipeline when not in pipeline mode\n"));
3088 return 0;
3089 }
3090
3091 switch (conn->asyncStatus)
3092 {
3093 case PGASYNC_COPY_IN:
3094 case PGASYNC_COPY_OUT:
3095 case PGASYNC_COPY_BOTH:
3096 /* should be unreachable */
3097 appendPQExpBufferStr(&conn->errorMessage,
3098 "internal error: cannot send pipeline while in COPY\n");
3099 return 0;
3100 case PGASYNC_READY:
3101 case PGASYNC_READY_MORE:
3102 case PGASYNC_BUSY:
3103 case PGASYNC_IDLE:
3104 /* OK to send sync */
3105 break;
3106 }
3107
3108 entry = pqAllocCmdQueueEntry(conn);
3109 if (entry == NULL)
3110 return 0; /* error msg already set */
3111
3112 entry->queryclass = PGQUERY_SYNC;
3113 entry->query = NULL;
3114
3115 /* construct the Sync message */
3116 if (pqPutMsgStart('S', conn) < 0 ||
3117 pqPutMsgEnd(conn) < 0)
3118 goto sendFailed;
3119
3120 /*
3121 * Give the data a push. In nonblock mode, don't complain if we're unable
3122 * to send it all; PQgetResult() will do any additional flushing needed.
3123 */
3124 if (PQflush(conn) < 0)
3125 goto sendFailed;
3126
3127 /* OK, it's launched! */
3128 pqAppendCmdQueueEntry(conn, entry);
3129
3130 return 1;
3131
3132 sendFailed:
3133 pqRecycleCmdQueueEntry(conn, entry);
3134 /* error message should be set up already */
3135 return 0;
3136 }
3137
3138 /*
3139 * PQsendFlushRequest
3140 * Send request for server to flush its buffer. Useful in pipeline
3141 * mode when a sync point is not desired.
3142 */
3143 int
PQsendFlushRequest(PGconn * conn)3144 PQsendFlushRequest(PGconn *conn)
3145 {
3146 if (!conn)
3147 return 0;
3148
3149 /* Don't try to send if we know there's no live connection. */
3150 if (conn->status != CONNECTION_OK)
3151 {
3152 appendPQExpBufferStr(&conn->errorMessage,
3153 libpq_gettext("no connection to the server\n"));
3154 return 0;
3155 }
3156
3157 /* Can't send while already busy, either, unless enqueuing for later */
3158 if (conn->asyncStatus != PGASYNC_IDLE &&
3159 conn->pipelineStatus == PQ_PIPELINE_OFF)
3160 {
3161 appendPQExpBufferStr(&conn->errorMessage,
3162 libpq_gettext("another command is already in progress\n"));
3163 return 0;
3164 }
3165
3166 if (pqPutMsgStart('H', conn) < 0 ||
3167 pqPutMsgEnd(conn) < 0)
3168 {
3169 return 0;
3170 }
3171
3172 return 1;
3173 }
3174
3175 /* ====== accessor funcs for PGresult ======== */
3176
3177 ExecStatusType
PQresultStatus(const PGresult * res)3178 PQresultStatus(const PGresult *res)
3179 {
3180 if (!res)
3181 return PGRES_FATAL_ERROR;
3182 return res->resultStatus;
3183 }
3184
3185 char *
PQresStatus(ExecStatusType status)3186 PQresStatus(ExecStatusType status)
3187 {
3188 if ((unsigned int) status >= lengthof(pgresStatus))
3189 return libpq_gettext("invalid ExecStatusType code");
3190 return pgresStatus[status];
3191 }
3192
3193 char *
PQresultErrorMessage(const PGresult * res)3194 PQresultErrorMessage(const PGresult *res)
3195 {
3196 if (!res || !res->errMsg)
3197 return "";
3198 return res->errMsg;
3199 }
3200
3201 char *
PQresultVerboseErrorMessage(const PGresult * res,PGVerbosity verbosity,PGContextVisibility show_context)3202 PQresultVerboseErrorMessage(const PGresult *res,
3203 PGVerbosity verbosity,
3204 PGContextVisibility show_context)
3205 {
3206 PQExpBufferData workBuf;
3207
3208 /*
3209 * Because the caller is expected to free the result string, we must
3210 * strdup any constant result. We use plain strdup and document that
3211 * callers should expect NULL if out-of-memory.
3212 */
3213 if (!res ||
3214 (res->resultStatus != PGRES_FATAL_ERROR &&
3215 res->resultStatus != PGRES_NONFATAL_ERROR))
3216 return strdup(libpq_gettext("PGresult is not an error result\n"));
3217
3218 initPQExpBuffer(&workBuf);
3219
3220 pqBuildErrorMessage3(&workBuf, res, verbosity, show_context);
3221
3222 /* If insufficient memory to format the message, fail cleanly */
3223 if (PQExpBufferDataBroken(workBuf))
3224 {
3225 termPQExpBuffer(&workBuf);
3226 return strdup(libpq_gettext("out of memory\n"));
3227 }
3228
3229 return workBuf.data;
3230 }
3231
3232 char *
PQresultErrorField(const PGresult * res,int fieldcode)3233 PQresultErrorField(const PGresult *res, int fieldcode)
3234 {
3235 PGMessageField *pfield;
3236
3237 if (!res)
3238 return NULL;
3239 for (pfield = res->errFields; pfield != NULL; pfield = pfield->next)
3240 {
3241 if (pfield->code == fieldcode)
3242 return pfield->contents;
3243 }
3244 return NULL;
3245 }
3246
3247 int
PQntuples(const PGresult * res)3248 PQntuples(const PGresult *res)
3249 {
3250 if (!res)
3251 return 0;
3252 return res->ntups;
3253 }
3254
3255 int
PQnfields(const PGresult * res)3256 PQnfields(const PGresult *res)
3257 {
3258 if (!res)
3259 return 0;
3260 return res->numAttributes;
3261 }
3262
3263 int
PQbinaryTuples(const PGresult * res)3264 PQbinaryTuples(const PGresult *res)
3265 {
3266 if (!res)
3267 return 0;
3268 return res->binary;
3269 }
3270
3271 /*
3272 * Helper routines to range-check field numbers and tuple numbers.
3273 * Return true if OK, false if not
3274 */
3275
3276 static int
check_field_number(const PGresult * res,int field_num)3277 check_field_number(const PGresult *res, int field_num)
3278 {
3279 if (!res)
3280 return false; /* no way to display error message... */
3281 if (field_num < 0 || field_num >= res->numAttributes)
3282 {
3283 pqInternalNotice(&res->noticeHooks,
3284 "column number %d is out of range 0..%d",
3285 field_num, res->numAttributes - 1);
3286 return false;
3287 }
3288 return true;
3289 }
3290
3291 static int
check_tuple_field_number(const PGresult * res,int tup_num,int field_num)3292 check_tuple_field_number(const PGresult *res,
3293 int tup_num, int field_num)
3294 {
3295 if (!res)
3296 return false; /* no way to display error message... */
3297 if (tup_num < 0 || tup_num >= res->ntups)
3298 {
3299 pqInternalNotice(&res->noticeHooks,
3300 "row number %d is out of range 0..%d",
3301 tup_num, res->ntups - 1);
3302 return false;
3303 }
3304 if (field_num < 0 || field_num >= res->numAttributes)
3305 {
3306 pqInternalNotice(&res->noticeHooks,
3307 "column number %d is out of range 0..%d",
3308 field_num, res->numAttributes - 1);
3309 return false;
3310 }
3311 return true;
3312 }
3313
3314 static int
check_param_number(const PGresult * res,int param_num)3315 check_param_number(const PGresult *res, int param_num)
3316 {
3317 if (!res)
3318 return false; /* no way to display error message... */
3319 if (param_num < 0 || param_num >= res->numParameters)
3320 {
3321 pqInternalNotice(&res->noticeHooks,
3322 "parameter number %d is out of range 0..%d",
3323 param_num, res->numParameters - 1);
3324 return false;
3325 }
3326
3327 return true;
3328 }
3329
3330 /*
3331 * returns NULL if the field_num is invalid
3332 */
3333 char *
PQfname(const PGresult * res,int field_num)3334 PQfname(const PGresult *res, int field_num)
3335 {
3336 if (!check_field_number(res, field_num))
3337 return NULL;
3338 if (res->attDescs)
3339 return res->attDescs[field_num].name;
3340 else
3341 return NULL;
3342 }
3343
3344 /*
3345 * PQfnumber: find column number given column name
3346 *
3347 * The column name is parsed as if it were in a SQL statement, including
3348 * case-folding and double-quote processing. But note a possible gotcha:
3349 * downcasing in the frontend might follow different locale rules than
3350 * downcasing in the backend...
3351 *
3352 * Returns -1 if no match. In the present backend it is also possible
3353 * to have multiple matches, in which case the first one is found.
3354 */
3355 int
PQfnumber(const PGresult * res,const char * field_name)3356 PQfnumber(const PGresult *res, const char *field_name)
3357 {
3358 char *field_case;
3359 bool in_quotes;
3360 bool all_lower = true;
3361 const char *iptr;
3362 char *optr;
3363 int i;
3364
3365 if (!res)
3366 return -1;
3367
3368 /*
3369 * Note: it is correct to reject a zero-length input string; the proper
3370 * input to match a zero-length field name would be "".
3371 */
3372 if (field_name == NULL ||
3373 field_name[0] == '\0' ||
3374 res->attDescs == NULL)
3375 return -1;
3376
3377 /*
3378 * Check if we can avoid the strdup() and related work because the
3379 * passed-in string wouldn't be changed before we do the check anyway.
3380 */
3381 for (iptr = field_name; *iptr; iptr++)
3382 {
3383 char c = *iptr;
3384
3385 if (c == '"' || c != pg_tolower((unsigned char) c))
3386 {
3387 all_lower = false;
3388 break;
3389 }
3390 }
3391
3392 if (all_lower)
3393 for (i = 0; i < res->numAttributes; i++)
3394 if (strcmp(field_name, res->attDescs[i].name) == 0)
3395 return i;
3396
3397 /* Fall through to the normal check if that didn't work out. */
3398
3399 /*
3400 * Note: this code will not reject partially quoted strings, eg
3401 * foo"BAR"foo will become fooBARfoo when it probably ought to be an error
3402 * condition.
3403 */
3404 field_case = strdup(field_name);
3405 if (field_case == NULL)
3406 return -1; /* grotty */
3407
3408 in_quotes = false;
3409 optr = field_case;
3410 for (iptr = field_case; *iptr; iptr++)
3411 {
3412 char c = *iptr;
3413
3414 if (in_quotes)
3415 {
3416 if (c == '"')
3417 {
3418 if (iptr[1] == '"')
3419 {
3420 /* doubled quotes become a single quote */
3421 *optr++ = '"';
3422 iptr++;
3423 }
3424 else
3425 in_quotes = false;
3426 }
3427 else
3428 *optr++ = c;
3429 }
3430 else if (c == '"')
3431 in_quotes = true;
3432 else
3433 {
3434 c = pg_tolower((unsigned char) c);
3435 *optr++ = c;
3436 }
3437 }
3438 *optr = '\0';
3439
3440 for (i = 0; i < res->numAttributes; i++)
3441 {
3442 if (strcmp(field_case, res->attDescs[i].name) == 0)
3443 {
3444 free(field_case);
3445 return i;
3446 }
3447 }
3448 free(field_case);
3449 return -1;
3450 }
3451
3452 Oid
PQftable(const PGresult * res,int field_num)3453 PQftable(const PGresult *res, int field_num)
3454 {
3455 if (!check_field_number(res, field_num))
3456 return InvalidOid;
3457 if (res->attDescs)
3458 return res->attDescs[field_num].tableid;
3459 else
3460 return InvalidOid;
3461 }
3462
3463 int
PQftablecol(const PGresult * res,int field_num)3464 PQftablecol(const PGresult *res, int field_num)
3465 {
3466 if (!check_field_number(res, field_num))
3467 return 0;
3468 if (res->attDescs)
3469 return res->attDescs[field_num].columnid;
3470 else
3471 return 0;
3472 }
3473
3474 int
PQfformat(const PGresult * res,int field_num)3475 PQfformat(const PGresult *res, int field_num)
3476 {
3477 if (!check_field_number(res, field_num))
3478 return 0;
3479 if (res->attDescs)
3480 return res->attDescs[field_num].format;
3481 else
3482 return 0;
3483 }
3484
3485 Oid
PQftype(const PGresult * res,int field_num)3486 PQftype(const PGresult *res, int field_num)
3487 {
3488 if (!check_field_number(res, field_num))
3489 return InvalidOid;
3490 if (res->attDescs)
3491 return res->attDescs[field_num].typid;
3492 else
3493 return InvalidOid;
3494 }
3495
3496 int
PQfsize(const PGresult * res,int field_num)3497 PQfsize(const PGresult *res, int field_num)
3498 {
3499 if (!check_field_number(res, field_num))
3500 return 0;
3501 if (res->attDescs)
3502 return res->attDescs[field_num].typlen;
3503 else
3504 return 0;
3505 }
3506
3507 int
PQfmod(const PGresult * res,int field_num)3508 PQfmod(const PGresult *res, int field_num)
3509 {
3510 if (!check_field_number(res, field_num))
3511 return 0;
3512 if (res->attDescs)
3513 return res->attDescs[field_num].atttypmod;
3514 else
3515 return 0;
3516 }
3517
3518 char *
PQcmdStatus(PGresult * res)3519 PQcmdStatus(PGresult *res)
3520 {
3521 if (!res)
3522 return NULL;
3523 return res->cmdStatus;
3524 }
3525
3526 /*
3527 * PQoidStatus -
3528 * if the last command was an INSERT, return the oid string
3529 * if not, return ""
3530 */
3531 char *
PQoidStatus(const PGresult * res)3532 PQoidStatus(const PGresult *res)
3533 {
3534 /*
3535 * This must be enough to hold the result. Don't laugh, this is better
3536 * than what this function used to do.
3537 */
3538 static char buf[24];
3539
3540 size_t len;
3541
3542 if (!res || strncmp(res->cmdStatus, "INSERT ", 7) != 0)
3543 return "";
3544
3545 len = strspn(res->cmdStatus + 7, "0123456789");
3546 if (len > sizeof(buf) - 1)
3547 len = sizeof(buf) - 1;
3548 memcpy(buf, res->cmdStatus + 7, len);
3549 buf[len] = '\0';
3550
3551 return buf;
3552 }
3553
3554 /*
3555 * PQoidValue -
3556 * a perhaps preferable form of the above which just returns
3557 * an Oid type
3558 */
3559 Oid
PQoidValue(const PGresult * res)3560 PQoidValue(const PGresult *res)
3561 {
3562 char *endptr = NULL;
3563 unsigned long result;
3564
3565 if (!res ||
3566 strncmp(res->cmdStatus, "INSERT ", 7) != 0 ||
3567 res->cmdStatus[7] < '0' ||
3568 res->cmdStatus[7] > '9')
3569 return InvalidOid;
3570
3571 result = strtoul(res->cmdStatus + 7, &endptr, 10);
3572
3573 if (!endptr || (*endptr != ' ' && *endptr != '\0'))
3574 return InvalidOid;
3575 else
3576 return (Oid) result;
3577 }
3578
3579
3580 /*
3581 * PQcmdTuples -
3582 * If the last command was INSERT/UPDATE/DELETE/MOVE/FETCH/COPY, return
3583 * a string containing the number of inserted/affected tuples. If not,
3584 * return "".
3585 *
3586 * XXX: this should probably return an int
3587 */
3588 char *
PQcmdTuples(PGresult * res)3589 PQcmdTuples(PGresult *res)
3590 {
3591 char *p,
3592 *c;
3593
3594 if (!res)
3595 return "";
3596
3597 if (strncmp(res->cmdStatus, "INSERT ", 7) == 0)
3598 {
3599 p = res->cmdStatus + 7;
3600 /* INSERT: skip oid and space */
3601 while (*p && *p != ' ')
3602 p++;
3603 if (*p == 0)
3604 goto interpret_error; /* no space? */
3605 p++;
3606 }
3607 else if (strncmp(res->cmdStatus, "SELECT ", 7) == 0 ||
3608 strncmp(res->cmdStatus, "DELETE ", 7) == 0 ||
3609 strncmp(res->cmdStatus, "UPDATE ", 7) == 0)
3610 p = res->cmdStatus + 7;
3611 else if (strncmp(res->cmdStatus, "FETCH ", 6) == 0)
3612 p = res->cmdStatus + 6;
3613 else if (strncmp(res->cmdStatus, "MOVE ", 5) == 0 ||
3614 strncmp(res->cmdStatus, "COPY ", 5) == 0)
3615 p = res->cmdStatus + 5;
3616 else
3617 return "";
3618
3619 /* check that we have an integer (at least one digit, nothing else) */
3620 for (c = p; *c; c++)
3621 {
3622 if (!isdigit((unsigned char) *c))
3623 goto interpret_error;
3624 }
3625 if (c == p)
3626 goto interpret_error;
3627
3628 return p;
3629
3630 interpret_error:
3631 pqInternalNotice(&res->noticeHooks,
3632 "could not interpret result from server: %s",
3633 res->cmdStatus);
3634 return "";
3635 }
3636
3637 /*
3638 * PQgetvalue:
3639 * return the value of field 'field_num' of row 'tup_num'
3640 */
3641 char *
PQgetvalue(const PGresult * res,int tup_num,int field_num)3642 PQgetvalue(const PGresult *res, int tup_num, int field_num)
3643 {
3644 if (!check_tuple_field_number(res, tup_num, field_num))
3645 return NULL;
3646 return res->tuples[tup_num][field_num].value;
3647 }
3648
3649 /* PQgetlength:
3650 * returns the actual length of a field value in bytes.
3651 */
3652 int
PQgetlength(const PGresult * res,int tup_num,int field_num)3653 PQgetlength(const PGresult *res, int tup_num, int field_num)
3654 {
3655 if (!check_tuple_field_number(res, tup_num, field_num))
3656 return 0;
3657 if (res->tuples[tup_num][field_num].len != NULL_LEN)
3658 return res->tuples[tup_num][field_num].len;
3659 else
3660 return 0;
3661 }
3662
3663 /* PQgetisnull:
3664 * returns the null status of a field value.
3665 */
3666 int
PQgetisnull(const PGresult * res,int tup_num,int field_num)3667 PQgetisnull(const PGresult *res, int tup_num, int field_num)
3668 {
3669 if (!check_tuple_field_number(res, tup_num, field_num))
3670 return 1; /* pretend it is null */
3671 if (res->tuples[tup_num][field_num].len == NULL_LEN)
3672 return 1;
3673 else
3674 return 0;
3675 }
3676
3677 /* PQnparams:
3678 * returns the number of input parameters of a prepared statement.
3679 */
3680 int
PQnparams(const PGresult * res)3681 PQnparams(const PGresult *res)
3682 {
3683 if (!res)
3684 return 0;
3685 return res->numParameters;
3686 }
3687
3688 /* PQparamtype:
3689 * returns type Oid of the specified statement parameter.
3690 */
3691 Oid
PQparamtype(const PGresult * res,int param_num)3692 PQparamtype(const PGresult *res, int param_num)
3693 {
3694 if (!check_param_number(res, param_num))
3695 return InvalidOid;
3696 if (res->paramDescs)
3697 return res->paramDescs[param_num].typid;
3698 else
3699 return InvalidOid;
3700 }
3701
3702
3703 /* PQsetnonblocking:
3704 * sets the PGconn's database connection non-blocking if the arg is true
3705 * or makes it blocking if the arg is false, this will not protect
3706 * you from PQexec(), you'll only be safe when using the non-blocking API.
3707 * Needs to be called only on a connected database connection.
3708 */
3709 int
PQsetnonblocking(PGconn * conn,int arg)3710 PQsetnonblocking(PGconn *conn, int arg)
3711 {
3712 bool barg;
3713
3714 if (!conn || conn->status == CONNECTION_BAD)
3715 return -1;
3716
3717 barg = (arg ? true : false);
3718
3719 /* early out if the socket is already in the state requested */
3720 if (barg == conn->nonblocking)
3721 return 0;
3722
3723 /*
3724 * to guarantee constancy for flushing/query/result-polling behavior we
3725 * need to flush the send queue at this point in order to guarantee proper
3726 * behavior. this is ok because either they are making a transition _from_
3727 * or _to_ blocking mode, either way we can block them.
3728 *
3729 * Clear errorMessage in case pqFlush adds to it.
3730 */
3731 resetPQExpBuffer(&conn->errorMessage);
3732
3733 /* if we are going from blocking to non-blocking flush here */
3734 if (pqFlush(conn))
3735 return -1;
3736
3737 conn->nonblocking = barg;
3738
3739 return 0;
3740 }
3741
3742 /*
3743 * return the blocking status of the database connection
3744 * true == nonblocking, false == blocking
3745 */
3746 int
PQisnonblocking(const PGconn * conn)3747 PQisnonblocking(const PGconn *conn)
3748 {
3749 return pqIsnonblocking(conn);
3750 }
3751
3752 /* libpq is thread-safe? */
3753 int
PQisthreadsafe(void)3754 PQisthreadsafe(void)
3755 {
3756 #ifdef ENABLE_THREAD_SAFETY
3757 return true;
3758 #else
3759 return false;
3760 #endif
3761 }
3762
3763
3764 /* try to force data out, really only useful for non-blocking users */
3765 int
PQflush(PGconn * conn)3766 PQflush(PGconn *conn)
3767 {
3768 return pqFlush(conn);
3769 }
3770
3771 /*
3772 * pqPipelineFlush
3773 *
3774 * In pipeline mode, data will be flushed only when the out buffer reaches the
3775 * threshold value. In non-pipeline mode, it behaves as stock pqFlush.
3776 *
3777 * Returns 0 on success.
3778 */
3779 static int
pqPipelineFlush(PGconn * conn)3780 pqPipelineFlush(PGconn *conn)
3781 {
3782 if ((conn->pipelineStatus != PQ_PIPELINE_ON) ||
3783 (conn->outCount >= OUTBUFFER_THRESHOLD))
3784 return pqFlush(conn);
3785 return 0;
3786 }
3787
3788
3789 /*
3790 * PQfreemem - safely frees memory allocated
3791 *
3792 * Needed mostly by Win32, unless multithreaded DLL (/MD in VC6)
3793 * Used for freeing memory from PQescapeBytea()/PQunescapeBytea()
3794 */
3795 void
PQfreemem(void * ptr)3796 PQfreemem(void *ptr)
3797 {
3798 free(ptr);
3799 }
3800
3801 /*
3802 * PQfreeNotify - free's the memory associated with a PGnotify
3803 *
3804 * This function is here only for binary backward compatibility.
3805 * New code should use PQfreemem(). A macro will automatically map
3806 * calls to PQfreemem. It should be removed in the future. bjm 2003-03-24
3807 */
3808
3809 #undef PQfreeNotify
3810 void PQfreeNotify(PGnotify *notify);
3811
3812 void
PQfreeNotify(PGnotify * notify)3813 PQfreeNotify(PGnotify *notify)
3814 {
3815 PQfreemem(notify);
3816 }
3817
3818
3819 /*
3820 * Escaping arbitrary strings to get valid SQL literal strings.
3821 *
3822 * Replaces "'" with "''", and if not std_strings, replaces "\" with "\\".
3823 *
3824 * length is the length of the source string. (Note: if a terminating NUL
3825 * is encountered sooner, PQescapeString stops short of "length"; the behavior
3826 * is thus rather like strncpy.)
3827 *
3828 * For safety the buffer at "to" must be at least 2*length + 1 bytes long.
3829 * A terminating NUL character is added to the output string, whether the
3830 * input is NUL-terminated or not.
3831 *
3832 * Returns the actual length of the output (not counting the terminating NUL).
3833 */
3834 static size_t
PQescapeStringInternal(PGconn * conn,char * to,const char * from,size_t length,int * error,int encoding,bool std_strings)3835 PQescapeStringInternal(PGconn *conn,
3836 char *to, const char *from, size_t length,
3837 int *error,
3838 int encoding, bool std_strings)
3839 {
3840 const char *source = from;
3841 char *target = to;
3842 size_t remaining = length;
3843
3844 if (error)
3845 *error = 0;
3846
3847 while (remaining > 0 && *source != '\0')
3848 {
3849 char c = *source;
3850 int len;
3851 int i;
3852
3853 /* Fast path for plain ASCII */
3854 if (!IS_HIGHBIT_SET(c))
3855 {
3856 /* Apply quoting if needed */
3857 if (SQL_STR_DOUBLE(c, !std_strings))
3858 *target++ = c;
3859 /* Copy the character */
3860 *target++ = c;
3861 source++;
3862 remaining--;
3863 continue;
3864 }
3865
3866 /* Slow path for possible multibyte characters */
3867 len = pg_encoding_mblen(encoding, source);
3868
3869 /* Copy the character */
3870 for (i = 0; i < len; i++)
3871 {
3872 if (remaining == 0 || *source == '\0')
3873 break;
3874 *target++ = *source++;
3875 remaining--;
3876 }
3877
3878 /*
3879 * If we hit premature end of string (ie, incomplete multibyte
3880 * character), try to pad out to the correct length with spaces. We
3881 * may not be able to pad completely, but we will always be able to
3882 * insert at least one pad space (since we'd not have quoted a
3883 * multibyte character). This should be enough to make a string that
3884 * the server will error out on.
3885 */
3886 if (i < len)
3887 {
3888 if (error)
3889 *error = 1;
3890 if (conn)
3891 appendPQExpBufferStr(&conn->errorMessage,
3892 libpq_gettext("incomplete multibyte character\n"));
3893 for (; i < len; i++)
3894 {
3895 if (((size_t) (target - to)) / 2 >= length)
3896 break;
3897 *target++ = ' ';
3898 }
3899 break;
3900 }
3901 }
3902
3903 /* Write the terminating NUL character. */
3904 *target = '\0';
3905
3906 return target - to;
3907 }
3908
3909 size_t
PQescapeStringConn(PGconn * conn,char * to,const char * from,size_t length,int * error)3910 PQescapeStringConn(PGconn *conn,
3911 char *to, const char *from, size_t length,
3912 int *error)
3913 {
3914 if (!conn)
3915 {
3916 /* force empty-string result */
3917 *to = '\0';
3918 if (error)
3919 *error = 1;
3920 return 0;
3921 }
3922
3923 resetPQExpBuffer(&conn->errorMessage);
3924
3925 return PQescapeStringInternal(conn, to, from, length, error,
3926 conn->client_encoding,
3927 conn->std_strings);
3928 }
3929
3930 size_t
PQescapeString(char * to,const char * from,size_t length)3931 PQescapeString(char *to, const char *from, size_t length)
3932 {
3933 return PQescapeStringInternal(NULL, to, from, length, NULL,
3934 static_client_encoding,
3935 static_std_strings);
3936 }
3937
3938
3939 /*
3940 * Escape arbitrary strings. If as_ident is true, we escape the result
3941 * as an identifier; if false, as a literal. The result is returned in
3942 * a newly allocated buffer. If we fail due to an encoding violation or out
3943 * of memory condition, we return NULL, storing an error message into conn.
3944 */
3945 static char *
PQescapeInternal(PGconn * conn,const char * str,size_t len,bool as_ident)3946 PQescapeInternal(PGconn *conn, const char *str, size_t len, bool as_ident)
3947 {
3948 const char *s;
3949 char *result;
3950 char *rp;
3951 int num_quotes = 0; /* single or double, depending on as_ident */
3952 int num_backslashes = 0;
3953 int input_len;
3954 int result_size;
3955 char quote_char = as_ident ? '"' : '\'';
3956
3957 /* We must have a connection, else fail immediately. */
3958 if (!conn)
3959 return NULL;
3960
3961 resetPQExpBuffer(&conn->errorMessage);
3962
3963 /* Scan the string for characters that must be escaped. */
3964 for (s = str; (s - str) < len && *s != '\0'; ++s)
3965 {
3966 if (*s == quote_char)
3967 ++num_quotes;
3968 else if (*s == '\\')
3969 ++num_backslashes;
3970 else if (IS_HIGHBIT_SET(*s))
3971 {
3972 int charlen;
3973
3974 /* Slow path for possible multibyte characters */
3975 charlen = pg_encoding_mblen(conn->client_encoding, s);
3976
3977 /* Multibyte character overruns allowable length. */
3978 if ((s - str) + charlen > len || memchr(s, 0, charlen) != NULL)
3979 {
3980 appendPQExpBufferStr(&conn->errorMessage,
3981 libpq_gettext("incomplete multibyte character\n"));
3982 return NULL;
3983 }
3984
3985 /* Adjust s, bearing in mind that for loop will increment it. */
3986 s += charlen - 1;
3987 }
3988 }
3989
3990 /* Allocate output buffer. */
3991 input_len = s - str;
3992 result_size = input_len + num_quotes + 3; /* two quotes, plus a NUL */
3993 if (!as_ident && num_backslashes > 0)
3994 result_size += num_backslashes + 2;
3995 result = rp = (char *) malloc(result_size);
3996 if (rp == NULL)
3997 {
3998 appendPQExpBufferStr(&conn->errorMessage,
3999 libpq_gettext("out of memory\n"));
4000 return NULL;
4001 }
4002
4003 /*
4004 * If we are escaping a literal that contains backslashes, we use the
4005 * escape string syntax so that the result is correct under either value
4006 * of standard_conforming_strings. We also emit a leading space in this
4007 * case, to guard against the possibility that the result might be
4008 * interpolated immediately following an identifier.
4009 */
4010 if (!as_ident && num_backslashes > 0)
4011 {
4012 *rp++ = ' ';
4013 *rp++ = 'E';
4014 }
4015
4016 /* Opening quote. */
4017 *rp++ = quote_char;
4018
4019 /*
4020 * Use fast path if possible.
4021 *
4022 * We've already verified that the input string is well-formed in the
4023 * current encoding. If it contains no quotes and, in the case of
4024 * literal-escaping, no backslashes, then we can just copy it directly to
4025 * the output buffer, adding the necessary quotes.
4026 *
4027 * If not, we must rescan the input and process each character
4028 * individually.
4029 */
4030 if (num_quotes == 0 && (num_backslashes == 0 || as_ident))
4031 {
4032 memcpy(rp, str, input_len);
4033 rp += input_len;
4034 }
4035 else
4036 {
4037 for (s = str; s - str < input_len; ++s)
4038 {
4039 if (*s == quote_char || (!as_ident && *s == '\\'))
4040 {
4041 *rp++ = *s;
4042 *rp++ = *s;
4043 }
4044 else if (!IS_HIGHBIT_SET(*s))
4045 *rp++ = *s;
4046 else
4047 {
4048 int i = pg_encoding_mblen(conn->client_encoding, s);
4049
4050 while (1)
4051 {
4052 *rp++ = *s;
4053 if (--i == 0)
4054 break;
4055 ++s; /* for loop will provide the final increment */
4056 }
4057 }
4058 }
4059 }
4060
4061 /* Closing quote and terminating NUL. */
4062 *rp++ = quote_char;
4063 *rp = '\0';
4064
4065 return result;
4066 }
4067
4068 char *
PQescapeLiteral(PGconn * conn,const char * str,size_t len)4069 PQescapeLiteral(PGconn *conn, const char *str, size_t len)
4070 {
4071 return PQescapeInternal(conn, str, len, false);
4072 }
4073
4074 char *
PQescapeIdentifier(PGconn * conn,const char * str,size_t len)4075 PQescapeIdentifier(PGconn *conn, const char *str, size_t len)
4076 {
4077 return PQescapeInternal(conn, str, len, true);
4078 }
4079
4080 /* HEX encoding support for bytea */
4081 static const char hextbl[] = "0123456789abcdef";
4082
4083 static const int8 hexlookup[128] = {
4084 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
4085 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
4086 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
4087 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
4088 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
4089 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
4090 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
4091 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
4092 };
4093
4094 static inline char
get_hex(char c)4095 get_hex(char c)
4096 {
4097 int res = -1;
4098
4099 if (c > 0 && c < 127)
4100 res = hexlookup[(unsigned char) c];
4101
4102 return (char) res;
4103 }
4104
4105
4106 /*
4107 * PQescapeBytea - converts from binary string to the
4108 * minimal encoding necessary to include the string in an SQL
4109 * INSERT statement with a bytea type column as the target.
4110 *
4111 * We can use either hex or escape (traditional) encoding.
4112 * In escape mode, the following transformations are applied:
4113 * '\0' == ASCII 0 == \000
4114 * '\'' == ASCII 39 == ''
4115 * '\\' == ASCII 92 == \\
4116 * anything < 0x20, or > 0x7e ---> \ooo
4117 * (where ooo is an octal expression)
4118 *
4119 * If not std_strings, all backslashes sent to the output are doubled.
4120 */
4121 static unsigned char *
PQescapeByteaInternal(PGconn * conn,const unsigned char * from,size_t from_length,size_t * to_length,bool std_strings,bool use_hex)4122 PQescapeByteaInternal(PGconn *conn,
4123 const unsigned char *from, size_t from_length,
4124 size_t *to_length, bool std_strings, bool use_hex)
4125 {
4126 const unsigned char *vp;
4127 unsigned char *rp;
4128 unsigned char *result;
4129 size_t i;
4130 size_t len;
4131 size_t bslash_len = (std_strings ? 1 : 2);
4132
4133 /*
4134 * empty string has 1 char ('\0')
4135 */
4136 len = 1;
4137
4138 if (use_hex)
4139 {
4140 len += bslash_len + 1 + 2 * from_length;
4141 }
4142 else
4143 {
4144 vp = from;
4145 for (i = from_length; i > 0; i--, vp++)
4146 {
4147 if (*vp < 0x20 || *vp > 0x7e)
4148 len += bslash_len + 3;
4149 else if (*vp == '\'')
4150 len += 2;
4151 else if (*vp == '\\')
4152 len += bslash_len + bslash_len;
4153 else
4154 len++;
4155 }
4156 }
4157
4158 *to_length = len;
4159 rp = result = (unsigned char *) malloc(len);
4160 if (rp == NULL)
4161 {
4162 if (conn)
4163 appendPQExpBufferStr(&conn->errorMessage,
4164 libpq_gettext("out of memory\n"));
4165 return NULL;
4166 }
4167
4168 if (use_hex)
4169 {
4170 if (!std_strings)
4171 *rp++ = '\\';
4172 *rp++ = '\\';
4173 *rp++ = 'x';
4174 }
4175
4176 vp = from;
4177 for (i = from_length; i > 0; i--, vp++)
4178 {
4179 unsigned char c = *vp;
4180
4181 if (use_hex)
4182 {
4183 *rp++ = hextbl[(c >> 4) & 0xF];
4184 *rp++ = hextbl[c & 0xF];
4185 }
4186 else if (c < 0x20 || c > 0x7e)
4187 {
4188 if (!std_strings)
4189 *rp++ = '\\';
4190 *rp++ = '\\';
4191 *rp++ = (c >> 6) + '0';
4192 *rp++ = ((c >> 3) & 07) + '0';
4193 *rp++ = (c & 07) + '0';
4194 }
4195 else if (c == '\'')
4196 {
4197 *rp++ = '\'';
4198 *rp++ = '\'';
4199 }
4200 else if (c == '\\')
4201 {
4202 if (!std_strings)
4203 {
4204 *rp++ = '\\';
4205 *rp++ = '\\';
4206 }
4207 *rp++ = '\\';
4208 *rp++ = '\\';
4209 }
4210 else
4211 *rp++ = c;
4212 }
4213 *rp = '\0';
4214
4215 return result;
4216 }
4217
4218 unsigned char *
PQescapeByteaConn(PGconn * conn,const unsigned char * from,size_t from_length,size_t * to_length)4219 PQescapeByteaConn(PGconn *conn,
4220 const unsigned char *from, size_t from_length,
4221 size_t *to_length)
4222 {
4223 if (!conn)
4224 return NULL;
4225
4226 resetPQExpBuffer(&conn->errorMessage);
4227
4228 return PQescapeByteaInternal(conn, from, from_length, to_length,
4229 conn->std_strings,
4230 (conn->sversion >= 90000));
4231 }
4232
4233 unsigned char *
PQescapeBytea(const unsigned char * from,size_t from_length,size_t * to_length)4234 PQescapeBytea(const unsigned char *from, size_t from_length, size_t *to_length)
4235 {
4236 return PQescapeByteaInternal(NULL, from, from_length, to_length,
4237 static_std_strings,
4238 false /* can't use hex */ );
4239 }
4240
4241
4242 #define ISFIRSTOCTDIGIT(CH) ((CH) >= '0' && (CH) <= '3')
4243 #define ISOCTDIGIT(CH) ((CH) >= '0' && (CH) <= '7')
4244 #define OCTVAL(CH) ((CH) - '0')
4245
4246 /*
4247 * PQunescapeBytea - converts the null terminated string representation
4248 * of a bytea, strtext, into binary, filling a buffer. It returns a
4249 * pointer to the buffer (or NULL on error), and the size of the
4250 * buffer in retbuflen. The pointer may subsequently be used as an
4251 * argument to the function PQfreemem.
4252 *
4253 * The following transformations are made:
4254 * \\ == ASCII 92 == \
4255 * \ooo == a byte whose value = ooo (ooo is an octal number)
4256 * \x == x (x is any character not matched by the above transformations)
4257 */
4258 unsigned char *
PQunescapeBytea(const unsigned char * strtext,size_t * retbuflen)4259 PQunescapeBytea(const unsigned char *strtext, size_t *retbuflen)
4260 {
4261 size_t strtextlen,
4262 buflen;
4263 unsigned char *buffer,
4264 *tmpbuf;
4265 size_t i,
4266 j;
4267
4268 if (strtext == NULL)
4269 return NULL;
4270
4271 strtextlen = strlen((const char *) strtext);
4272
4273 if (strtext[0] == '\\' && strtext[1] == 'x')
4274 {
4275 const unsigned char *s;
4276 unsigned char *p;
4277
4278 buflen = (strtextlen - 2) / 2;
4279 /* Avoid unportable malloc(0) */
4280 buffer = (unsigned char *) malloc(buflen > 0 ? buflen : 1);
4281 if (buffer == NULL)
4282 return NULL;
4283
4284 s = strtext + 2;
4285 p = buffer;
4286 while (*s)
4287 {
4288 char v1,
4289 v2;
4290
4291 /*
4292 * Bad input is silently ignored. Note that this includes
4293 * whitespace between hex pairs, which is allowed by byteain.
4294 */
4295 v1 = get_hex(*s++);
4296 if (!*s || v1 == (char) -1)
4297 continue;
4298 v2 = get_hex(*s++);
4299 if (v2 != (char) -1)
4300 *p++ = (v1 << 4) | v2;
4301 }
4302
4303 buflen = p - buffer;
4304 }
4305 else
4306 {
4307 /*
4308 * Length of input is max length of output, but add one to avoid
4309 * unportable malloc(0) if input is zero-length.
4310 */
4311 buffer = (unsigned char *) malloc(strtextlen + 1);
4312 if (buffer == NULL)
4313 return NULL;
4314
4315 for (i = j = 0; i < strtextlen;)
4316 {
4317 switch (strtext[i])
4318 {
4319 case '\\':
4320 i++;
4321 if (strtext[i] == '\\')
4322 buffer[j++] = strtext[i++];
4323 else
4324 {
4325 if ((ISFIRSTOCTDIGIT(strtext[i])) &&
4326 (ISOCTDIGIT(strtext[i + 1])) &&
4327 (ISOCTDIGIT(strtext[i + 2])))
4328 {
4329 int byte;
4330
4331 byte = OCTVAL(strtext[i++]);
4332 byte = (byte << 3) + OCTVAL(strtext[i++]);
4333 byte = (byte << 3) + OCTVAL(strtext[i++]);
4334 buffer[j++] = byte;
4335 }
4336 }
4337
4338 /*
4339 * Note: if we see '\' followed by something that isn't a
4340 * recognized escape sequence, we loop around having done
4341 * nothing except advance i. Therefore the something will
4342 * be emitted as ordinary data on the next cycle. Corner
4343 * case: '\' at end of string will just be discarded.
4344 */
4345 break;
4346
4347 default:
4348 buffer[j++] = strtext[i++];
4349 break;
4350 }
4351 }
4352 buflen = j; /* buflen is the length of the dequoted data */
4353 }
4354
4355 /* Shrink the buffer to be no larger than necessary */
4356 /* +1 avoids unportable behavior when buflen==0 */
4357 tmpbuf = realloc(buffer, buflen + 1);
4358
4359 /* It would only be a very brain-dead realloc that could fail, but... */
4360 if (!tmpbuf)
4361 {
4362 free(buffer);
4363 return NULL;
4364 }
4365
4366 *retbuflen = buflen;
4367 return tmpbuf;
4368 }
4369