Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * FILE
4 : * fe-misc.c
5 : *
6 : * DESCRIPTION
7 : * miscellaneous useful functions
8 : *
9 : * The communication routines here are analogous to the ones in
10 : * backend/libpq/pqcomm.c and backend/libpq/pqformat.c, but operate
11 : * in the considerably different environment of the frontend libpq.
12 : * In particular, we work with a bare nonblock-mode socket, rather than
13 : * a stdio stream, so that we can avoid unwanted blocking of the application.
14 : *
15 : * XXX: MOVE DEBUG PRINTOUT TO HIGHER LEVEL. As is, block and restart
16 : * will cause repeat printouts.
17 : *
18 : * We must speak the same transmitted data representations as the backend
19 : * routines.
20 : *
21 : *
22 : * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
23 : * Portions Copyright (c) 1994, Regents of the University of California
24 : *
25 : * IDENTIFICATION
26 : * src/interfaces/libpq/fe-misc.c
27 : *
28 : *-------------------------------------------------------------------------
29 : */
30 :
31 : #include "postgres_fe.h"
32 :
33 : #include <signal.h>
34 : #include <time.h>
35 :
36 : #ifdef WIN32
37 : #include "win32.h"
38 : #else
39 : #include <unistd.h>
40 : #include <sys/select.h>
41 : #include <sys/time.h>
42 : #endif
43 :
44 : #ifdef HAVE_POLL_H
45 : #include <poll.h>
46 : #endif
47 :
48 : #include "libpq-fe.h"
49 : #include "libpq-int.h"
50 : #include "mb/pg_wchar.h"
51 : #include "pg_config_paths.h"
52 : #include "port/pg_bswap.h"
53 :
54 : static int pqPutMsgBytes(const void *buf, size_t len, PGconn *conn);
55 : static int pqSendSome(PGconn *conn, int len);
56 : static int pqSocketCheck(PGconn *conn, int forRead, int forWrite,
57 : pg_usec_time_t end_time);
58 :
59 : /*
60 : * PQlibVersion: return the libpq version number
61 : */
62 : int
63 0 : PQlibVersion(void)
64 : {
65 0 : return PG_VERSION_NUM;
66 : }
67 :
68 :
69 : /*
70 : * pqGetc: get 1 character from the connection
71 : *
72 : * All these routines return 0 on success, EOF on error.
73 : * Note that for the Get routines, EOF only means there is not enough
74 : * data in the buffer, not that there is necessarily a hard error.
75 : */
76 : int
77 19820878 : pqGetc(char *result, PGconn *conn)
78 : {
79 19820878 : if (conn->inCursor >= conn->inEnd)
80 2835246 : return EOF;
81 :
82 16985632 : *result = conn->inBuffer[conn->inCursor++];
83 :
84 16985632 : return 0;
85 : }
86 :
87 :
88 : /*
89 : * pqPutc: write 1 char to the current message
90 : */
91 : int
92 21524 : pqPutc(char c, PGconn *conn)
93 : {
94 21524 : if (pqPutMsgBytes(&c, 1, conn))
95 0 : return EOF;
96 :
97 21524 : return 0;
98 : }
99 :
100 :
101 : /*
102 : * pqGets[_append]:
103 : * get a null-terminated string from the connection,
104 : * and store it in an expansible PQExpBuffer.
105 : * If we run out of memory, all of the string is still read,
106 : * but the excess characters are silently discarded.
107 : */
108 : static int
109 3846422 : pqGets_internal(PQExpBuffer buf, PGconn *conn, bool resetbuffer)
110 : {
111 : /* Copy conn data to locals for faster search loop */
112 3846422 : char *inBuffer = conn->inBuffer;
113 3846422 : int inCursor = conn->inCursor;
114 3846422 : int inEnd = conn->inEnd;
115 : int slen;
116 :
117 75839494 : while (inCursor < inEnd && inBuffer[inCursor])
118 71993072 : inCursor++;
119 :
120 3846422 : if (inCursor >= inEnd)
121 0 : return EOF;
122 :
123 3846422 : slen = inCursor - conn->inCursor;
124 :
125 3846422 : if (resetbuffer)
126 3846422 : resetPQExpBuffer(buf);
127 :
128 3846422 : appendBinaryPQExpBuffer(buf, inBuffer + conn->inCursor, slen);
129 :
130 3846422 : conn->inCursor = ++inCursor;
131 :
132 3846422 : return 0;
133 : }
134 :
135 : int
136 3846422 : pqGets(PQExpBuffer buf, PGconn *conn)
137 : {
138 3846422 : return pqGets_internal(buf, conn, true);
139 : }
140 :
141 : int
142 0 : pqGets_append(PQExpBuffer buf, PGconn *conn)
143 : {
144 0 : return pqGets_internal(buf, conn, false);
145 : }
146 :
147 :
148 : /*
149 : * pqPuts: write a null-terminated string to the current message
150 : */
151 : int
152 663212 : pqPuts(const char *s, PGconn *conn)
153 : {
154 663212 : if (pqPutMsgBytes(s, strlen(s) + 1, conn))
155 0 : return EOF;
156 :
157 663212 : return 0;
158 : }
159 :
160 : /*
161 : * pqGetnchar:
162 : * get a string of exactly len bytes in buffer s, no null termination
163 : */
164 : int
165 874 : pqGetnchar(char *s, size_t len, PGconn *conn)
166 : {
167 874 : if (len > (size_t) (conn->inEnd - conn->inCursor))
168 0 : return EOF;
169 :
170 874 : memcpy(s, conn->inBuffer + conn->inCursor, len);
171 : /* no terminating null */
172 :
173 874 : conn->inCursor += len;
174 :
175 874 : return 0;
176 : }
177 :
178 : /*
179 : * pqSkipnchar:
180 : * skip over len bytes in input buffer.
181 : *
182 : * Note: this is primarily useful for its debug output, which should
183 : * be exactly the same as for pqGetnchar. We assume the data in question
184 : * will actually be used, but just isn't getting copied anywhere as yet.
185 : */
186 : int
187 28526020 : pqSkipnchar(size_t len, PGconn *conn)
188 : {
189 28526020 : if (len > (size_t) (conn->inEnd - conn->inCursor))
190 0 : return EOF;
191 :
192 28526020 : conn->inCursor += len;
193 :
194 28526020 : return 0;
195 : }
196 :
197 : /*
198 : * pqPutnchar:
199 : * write exactly len bytes to the current message
200 : */
201 : int
202 524016 : pqPutnchar(const char *s, size_t len, PGconn *conn)
203 : {
204 524016 : if (pqPutMsgBytes(s, len, conn))
205 0 : return EOF;
206 :
207 524016 : return 0;
208 : }
209 :
210 : /*
211 : * pqGetInt
212 : * read a 2 or 4 byte integer and convert from network byte order
213 : * to local byte order
214 : */
215 : int
216 57446272 : pqGetInt(int *result, size_t bytes, PGconn *conn)
217 : {
218 : uint16 tmp2;
219 : uint32 tmp4;
220 :
221 57446272 : switch (bytes)
222 : {
223 9563498 : case 2:
224 9563498 : if (conn->inCursor + 2 > conn->inEnd)
225 0 : return EOF;
226 9563498 : memcpy(&tmp2, conn->inBuffer + conn->inCursor, 2);
227 9563498 : conn->inCursor += 2;
228 9563498 : *result = (int) pg_ntoh16(tmp2);
229 9563498 : break;
230 47882774 : case 4:
231 47882774 : if (conn->inCursor + 4 > conn->inEnd)
232 4296 : return EOF;
233 47878478 : memcpy(&tmp4, conn->inBuffer + conn->inCursor, 4);
234 47878478 : conn->inCursor += 4;
235 47878478 : *result = (int) pg_ntoh32(tmp4);
236 47878478 : break;
237 0 : default:
238 0 : pqInternalNotice(&conn->noticeHooks,
239 : "integer of size %lu not supported by pqGetInt",
240 : (unsigned long) bytes);
241 0 : return EOF;
242 : }
243 :
244 57441976 : return 0;
245 : }
246 :
247 : /*
248 : * pqPutInt
249 : * write an integer of 2 or 4 bytes, converting from host byte order
250 : * to network byte order.
251 : */
252 : int
253 170170 : pqPutInt(int value, size_t bytes, PGconn *conn)
254 : {
255 : uint16 tmp2;
256 : uint32 tmp4;
257 :
258 170170 : switch (bytes)
259 : {
260 110942 : case 2:
261 110942 : tmp2 = pg_hton16((uint16) value);
262 110942 : if (pqPutMsgBytes((const char *) &tmp2, 2, conn))
263 0 : return EOF;
264 110942 : break;
265 59228 : case 4:
266 59228 : tmp4 = pg_hton32((uint32) value);
267 59228 : if (pqPutMsgBytes((const char *) &tmp4, 4, conn))
268 0 : return EOF;
269 59228 : break;
270 0 : default:
271 0 : pqInternalNotice(&conn->noticeHooks,
272 : "integer of size %lu not supported by pqPutInt",
273 : (unsigned long) bytes);
274 0 : return EOF;
275 : }
276 :
277 170170 : return 0;
278 : }
279 :
280 : /*
281 : * Make sure conn's output buffer can hold bytes_needed bytes (caller must
282 : * include already-stored data into the value!)
283 : *
284 : * Returns 0 on success, EOF if failed to enlarge buffer
285 : */
286 : int
287 2557110 : pqCheckOutBufferSpace(size_t bytes_needed, PGconn *conn)
288 : {
289 2557110 : int newsize = conn->outBufSize;
290 : char *newbuf;
291 :
292 : /* Quick exit if we have enough space */
293 2557110 : if (bytes_needed <= (size_t) newsize)
294 2557054 : return 0;
295 :
296 : /*
297 : * If we need to enlarge the buffer, we first try to double it in size; if
298 : * that doesn't work, enlarge in multiples of 8K. This avoids thrashing
299 : * the malloc pool by repeated small enlargements.
300 : *
301 : * Note: tests for newsize > 0 are to catch integer overflow.
302 : */
303 : do
304 : {
305 144 : newsize *= 2;
306 144 : } while (newsize > 0 && bytes_needed > (size_t) newsize);
307 :
308 56 : if (newsize > 0 && bytes_needed <= (size_t) newsize)
309 : {
310 56 : newbuf = realloc(conn->outBuffer, newsize);
311 56 : if (newbuf)
312 : {
313 : /* realloc succeeded */
314 56 : conn->outBuffer = newbuf;
315 56 : conn->outBufSize = newsize;
316 56 : return 0;
317 : }
318 : }
319 :
320 0 : newsize = conn->outBufSize;
321 : do
322 : {
323 0 : newsize += 8192;
324 0 : } while (newsize > 0 && bytes_needed > (size_t) newsize);
325 :
326 0 : if (newsize > 0 && bytes_needed <= (size_t) newsize)
327 : {
328 0 : newbuf = realloc(conn->outBuffer, newsize);
329 0 : if (newbuf)
330 : {
331 : /* realloc succeeded */
332 0 : conn->outBuffer = newbuf;
333 0 : conn->outBufSize = newsize;
334 0 : return 0;
335 : }
336 : }
337 :
338 : /* realloc failed. Probably out of memory */
339 0 : appendPQExpBufferStr(&conn->errorMessage,
340 : "cannot allocate memory for output buffer\n");
341 0 : return EOF;
342 : }
343 :
344 : /*
345 : * Make sure conn's input buffer can hold bytes_needed bytes (caller must
346 : * include already-stored data into the value!)
347 : *
348 : * Returns 0 on success, EOF if failed to enlarge buffer
349 : */
350 : int
351 429466 : pqCheckInBufferSpace(size_t bytes_needed, PGconn *conn)
352 : {
353 429466 : int newsize = conn->inBufSize;
354 : char *newbuf;
355 :
356 : /* Quick exit if we have enough space */
357 429466 : if (bytes_needed <= (size_t) newsize)
358 174756 : return 0;
359 :
360 : /*
361 : * Before concluding that we need to enlarge the buffer, left-justify
362 : * whatever is in it and recheck. The caller's value of bytes_needed
363 : * includes any data to the left of inStart, but we can delete that in
364 : * preference to enlarging the buffer. It's slightly ugly to have this
365 : * function do this, but it's better than making callers worry about it.
366 : */
367 254710 : bytes_needed -= conn->inStart;
368 :
369 254710 : if (conn->inStart < conn->inEnd)
370 : {
371 254710 : if (conn->inStart > 0)
372 : {
373 254192 : memmove(conn->inBuffer, conn->inBuffer + conn->inStart,
374 254192 : conn->inEnd - conn->inStart);
375 254192 : conn->inEnd -= conn->inStart;
376 254192 : conn->inCursor -= conn->inStart;
377 254192 : conn->inStart = 0;
378 : }
379 : }
380 : else
381 : {
382 : /* buffer is logically empty, reset it */
383 0 : conn->inStart = conn->inCursor = conn->inEnd = 0;
384 : }
385 :
386 : /* Recheck whether we have enough space */
387 254710 : if (bytes_needed <= (size_t) newsize)
388 253316 : return 0;
389 :
390 : /*
391 : * If we need to enlarge the buffer, we first try to double it in size; if
392 : * that doesn't work, enlarge in multiples of 8K. This avoids thrashing
393 : * the malloc pool by repeated small enlargements.
394 : *
395 : * Note: tests for newsize > 0 are to catch integer overflow.
396 : */
397 : do
398 : {
399 2494 : newsize *= 2;
400 2494 : } while (newsize > 0 && bytes_needed > (size_t) newsize);
401 :
402 1394 : if (newsize > 0 && bytes_needed <= (size_t) newsize)
403 : {
404 1394 : newbuf = realloc(conn->inBuffer, newsize);
405 1394 : if (newbuf)
406 : {
407 : /* realloc succeeded */
408 1394 : conn->inBuffer = newbuf;
409 1394 : conn->inBufSize = newsize;
410 1394 : return 0;
411 : }
412 : }
413 :
414 0 : newsize = conn->inBufSize;
415 : do
416 : {
417 0 : newsize += 8192;
418 0 : } while (newsize > 0 && bytes_needed > (size_t) newsize);
419 :
420 0 : if (newsize > 0 && bytes_needed <= (size_t) newsize)
421 : {
422 0 : newbuf = realloc(conn->inBuffer, newsize);
423 0 : if (newbuf)
424 : {
425 : /* realloc succeeded */
426 0 : conn->inBuffer = newbuf;
427 0 : conn->inBufSize = newsize;
428 0 : return 0;
429 : }
430 : }
431 :
432 : /* realloc failed. Probably out of memory */
433 0 : appendPQExpBufferStr(&conn->errorMessage,
434 : "cannot allocate memory for input buffer\n");
435 0 : return EOF;
436 : }
437 :
438 : /*
439 : * pqParseDone: after a server-to-client message has successfully
440 : * been parsed, advance conn->inStart to account for it.
441 : */
442 : void
443 13455040 : pqParseDone(PGconn *conn, int newInStart)
444 : {
445 : /* trace server-to-client message */
446 13455040 : if (conn->Pfdebug)
447 434 : pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false);
448 :
449 : /* Mark message as done */
450 13455040 : conn->inStart = newInStart;
451 13455040 : }
452 :
453 : /*
454 : * pqPutMsgStart: begin construction of a message to the server
455 : *
456 : * msg_type is the message type byte, or 0 for a message without type byte
457 : * (only startup messages have no type byte)
458 : *
459 : * Returns 0 on success, EOF on error
460 : *
461 : * The idea here is that we construct the message in conn->outBuffer,
462 : * beginning just past any data already in outBuffer (ie, at
463 : * outBuffer+outCount). We enlarge the buffer as needed to hold the message.
464 : * When the message is complete, we fill in the length word (if needed) and
465 : * then advance outCount past the message, making it eligible to send.
466 : *
467 : * The state variable conn->outMsgStart points to the incomplete message's
468 : * length word: it is either outCount or outCount+1 depending on whether
469 : * there is a type byte. The state variable conn->outMsgEnd is the end of
470 : * the data collected so far.
471 : */
472 : int
473 1178148 : pqPutMsgStart(char msg_type, PGconn *conn)
474 : {
475 : int lenPos;
476 : int endPos;
477 :
478 : /* allow room for message type byte */
479 1178148 : if (msg_type)
480 1151556 : endPos = conn->outCount + 1;
481 : else
482 26592 : endPos = conn->outCount;
483 :
484 : /* do we want a length word? */
485 1178148 : lenPos = endPos;
486 : /* allow room for message length */
487 1178148 : endPos += 4;
488 :
489 : /* make sure there is room for message header */
490 1178148 : if (pqCheckOutBufferSpace(endPos, conn))
491 0 : return EOF;
492 : /* okay, save the message type byte if any */
493 1178148 : if (msg_type)
494 1151556 : conn->outBuffer[conn->outCount] = msg_type;
495 : /* set up the message pointers */
496 1178148 : conn->outMsgStart = lenPos;
497 1178148 : conn->outMsgEnd = endPos;
498 : /* length word, if needed, will be filled in by pqPutMsgEnd */
499 :
500 1178148 : return 0;
501 : }
502 :
503 : /*
504 : * pqPutMsgBytes: add bytes to a partially-constructed message
505 : *
506 : * Returns 0 on success, EOF on error
507 : */
508 : static int
509 1378922 : pqPutMsgBytes(const void *buf, size_t len, PGconn *conn)
510 : {
511 : /* make sure there is room for it */
512 1378922 : if (pqCheckOutBufferSpace(conn->outMsgEnd + len, conn))
513 0 : return EOF;
514 : /* okay, save the data */
515 1378922 : memcpy(conn->outBuffer + conn->outMsgEnd, buf, len);
516 1378922 : conn->outMsgEnd += len;
517 : /* no Pfdebug call here, caller should do it */
518 1378922 : return 0;
519 : }
520 :
521 : /*
522 : * pqPutMsgEnd: finish constructing a message and possibly send it
523 : *
524 : * Returns 0 on success, EOF on error
525 : *
526 : * We don't actually send anything here unless we've accumulated at least
527 : * 8K worth of data (the typical size of a pipe buffer on Unix systems).
528 : * This avoids sending small partial packets. The caller must use pqFlush
529 : * when it's important to flush all the data out to the server.
530 : */
531 : int
532 1178148 : pqPutMsgEnd(PGconn *conn)
533 : {
534 : /* Fill in length word if needed */
535 1178148 : if (conn->outMsgStart >= 0)
536 : {
537 1178148 : uint32 msgLen = conn->outMsgEnd - conn->outMsgStart;
538 :
539 1178148 : msgLen = pg_hton32(msgLen);
540 1178148 : memcpy(conn->outBuffer + conn->outMsgStart, &msgLen, 4);
541 : }
542 :
543 : /* trace client-to-server message */
544 1178148 : if (conn->Pfdebug)
545 : {
546 394 : if (conn->outCount < conn->outMsgStart)
547 394 : pqTraceOutputMessage(conn, conn->outBuffer + conn->outCount, true);
548 : else
549 0 : pqTraceOutputNoTypeByteMessage(conn,
550 0 : conn->outBuffer + conn->outMsgStart);
551 : }
552 :
553 : /* Make message eligible to send */
554 1178148 : conn->outCount = conn->outMsgEnd;
555 :
556 1178148 : if (conn->outCount >= 8192)
557 : {
558 2044 : int toSend = conn->outCount - (conn->outCount % 8192);
559 :
560 2044 : if (pqSendSome(conn, toSend) < 0)
561 0 : return EOF;
562 : /* in nonblock mode, don't complain if unable to send it all */
563 : }
564 :
565 1178148 : return 0;
566 : }
567 :
568 : /* ----------
569 : * pqReadData: read more data, if any is available
570 : * Possible return values:
571 : * 1: successfully loaded at least one more byte
572 : * 0: no data is presently available, but no error detected
573 : * -1: error detected (including EOF = connection closure);
574 : * conn->errorMessage set
575 : * NOTE: callers must not assume that pointers or indexes into conn->inBuffer
576 : * remain valid across this call!
577 : * ----------
578 : */
579 : int
580 1860538 : pqReadData(PGconn *conn)
581 : {
582 1860538 : int someread = 0;
583 : int nread;
584 :
585 1860538 : if (conn->sock == PGINVALID_SOCKET)
586 : {
587 4 : libpq_append_conn_error(conn, "connection not open");
588 4 : return -1;
589 : }
590 :
591 : /* Left-justify any data in the buffer to make room */
592 1860534 : if (conn->inStart < conn->inEnd)
593 : {
594 407936 : if (conn->inStart > 0)
595 : {
596 113028 : memmove(conn->inBuffer, conn->inBuffer + conn->inStart,
597 113028 : conn->inEnd - conn->inStart);
598 113028 : conn->inEnd -= conn->inStart;
599 113028 : conn->inCursor -= conn->inStart;
600 113028 : conn->inStart = 0;
601 : }
602 : }
603 : else
604 : {
605 : /* buffer is logically empty, reset it */
606 1452598 : conn->inStart = conn->inCursor = conn->inEnd = 0;
607 : }
608 :
609 : /*
610 : * If the buffer is fairly full, enlarge it. We need to be able to enlarge
611 : * the buffer in case a single message exceeds the initial buffer size. We
612 : * enlarge before filling the buffer entirely so as to avoid asking the
613 : * kernel for a partial packet. The magic constant here should be large
614 : * enough for a TCP packet or Unix pipe bufferload. 8K is the usual pipe
615 : * buffer size, so...
616 : */
617 1860534 : if (conn->inBufSize - conn->inEnd < 8192)
618 : {
619 2 : if (pqCheckInBufferSpace(conn->inEnd + (size_t) 8192, conn))
620 : {
621 : /*
622 : * We don't insist that the enlarge worked, but we need some room
623 : */
624 0 : if (conn->inBufSize - conn->inEnd < 100)
625 0 : return -1; /* errorMessage already set */
626 : }
627 : }
628 :
629 : /* OK, try to read some data */
630 1860534 : retry3:
631 3989548 : nread = pqsecure_read(conn, conn->inBuffer + conn->inEnd,
632 1994774 : conn->inBufSize - conn->inEnd);
633 1994774 : if (nread < 0)
634 : {
635 590496 : switch (SOCK_ERRNO)
636 : {
637 0 : case EINTR:
638 0 : goto retry3;
639 :
640 : /* Some systems return EAGAIN/EWOULDBLOCK for no data */
641 : #ifdef EAGAIN
642 590468 : case EAGAIN:
643 590468 : return someread;
644 : #endif
645 : #if defined(EWOULDBLOCK) && (!defined(EAGAIN) || (EWOULDBLOCK != EAGAIN))
646 : case EWOULDBLOCK:
647 : return someread;
648 : #endif
649 :
650 : /* We might get ECONNRESET etc here if connection failed */
651 28 : case ALL_CONNECTION_FAILURE_ERRNOS:
652 28 : goto definitelyFailed;
653 :
654 0 : default:
655 : /* pqsecure_read set the error message for us */
656 0 : return -1;
657 : }
658 : }
659 1404278 : if (nread > 0)
660 : {
661 1403918 : conn->inEnd += nread;
662 :
663 : /*
664 : * Hack to deal with the fact that some kernels will only give us back
665 : * 1 packet per recv() call, even if we asked for more and there is
666 : * more available. If it looks like we are reading a long message,
667 : * loop back to recv() again immediately, until we run out of data or
668 : * buffer space. Without this, the block-and-restart behavior of
669 : * libpq's higher levels leads to O(N^2) performance on long messages.
670 : *
671 : * Since we left-justified the data above, conn->inEnd gives the
672 : * amount of data already read in the current message. We consider
673 : * the message "long" once we have acquired 32k ...
674 : */
675 1403918 : if (conn->inEnd > 32768 &&
676 340206 : (conn->inBufSize - conn->inEnd) >= 8192)
677 : {
678 134240 : someread = 1;
679 134240 : goto retry3;
680 : }
681 1269678 : return 1;
682 : }
683 :
684 360 : if (someread)
685 0 : return 1; /* got a zero read after successful tries */
686 :
687 : /*
688 : * A return value of 0 could mean just that no data is now available, or
689 : * it could mean EOF --- that is, the server has closed the connection.
690 : * Since we have the socket in nonblock mode, the only way to tell the
691 : * difference is to see if select() is saying that the file is ready.
692 : * Grumble. Fortunately, we don't expect this path to be taken much,
693 : * since in normal practice we should not be trying to read data unless
694 : * the file selected for reading already.
695 : *
696 : * In SSL mode it's even worse: SSL_read() could say WANT_READ and then
697 : * data could arrive before we make the pqReadReady() test, but the second
698 : * SSL_read() could still say WANT_READ because the data received was not
699 : * a complete SSL record. So we must play dumb and assume there is more
700 : * data, relying on the SSL layer to detect true EOF.
701 : */
702 :
703 : #ifdef USE_SSL
704 360 : if (conn->ssl_in_use)
705 166 : return 0;
706 : #endif
707 :
708 194 : switch (pqReadReady(conn))
709 : {
710 0 : case 0:
711 : /* definitely no data available */
712 0 : return 0;
713 194 : case 1:
714 : /* ready for read */
715 194 : break;
716 0 : default:
717 : /* we override pqReadReady's message with something more useful */
718 0 : goto definitelyEOF;
719 : }
720 :
721 : /*
722 : * Still not sure that it's EOF, because some data could have just
723 : * arrived.
724 : */
725 194 : retry4:
726 388 : nread = pqsecure_read(conn, conn->inBuffer + conn->inEnd,
727 194 : conn->inBufSize - conn->inEnd);
728 194 : if (nread < 0)
729 : {
730 0 : switch (SOCK_ERRNO)
731 : {
732 0 : case EINTR:
733 0 : goto retry4;
734 :
735 : /* Some systems return EAGAIN/EWOULDBLOCK for no data */
736 : #ifdef EAGAIN
737 0 : case EAGAIN:
738 0 : return 0;
739 : #endif
740 : #if defined(EWOULDBLOCK) && (!defined(EAGAIN) || (EWOULDBLOCK != EAGAIN))
741 : case EWOULDBLOCK:
742 : return 0;
743 : #endif
744 :
745 : /* We might get ECONNRESET etc here if connection failed */
746 0 : case ALL_CONNECTION_FAILURE_ERRNOS:
747 0 : goto definitelyFailed;
748 :
749 0 : default:
750 : /* pqsecure_read set the error message for us */
751 0 : return -1;
752 : }
753 : }
754 194 : if (nread > 0)
755 : {
756 0 : conn->inEnd += nread;
757 0 : return 1;
758 : }
759 :
760 : /*
761 : * OK, we are getting a zero read even though select() says ready. This
762 : * means the connection has been closed. Cope.
763 : */
764 194 : definitelyEOF:
765 194 : libpq_append_conn_error(conn, "server closed the connection unexpectedly\n"
766 : "\tThis probably means the server terminated abnormally\n"
767 : "\tbefore or while processing the request.");
768 :
769 : /* Come here if lower-level code already set a suitable errorMessage */
770 222 : definitelyFailed:
771 : /* Do *not* drop any already-read data; caller still wants it */
772 222 : pqDropConnection(conn, false);
773 222 : conn->status = CONNECTION_BAD; /* No more connection to backend */
774 222 : return -1;
775 : }
776 :
777 : /*
778 : * pqSendSome: send data waiting in the output buffer.
779 : *
780 : * len is how much to try to send (typically equal to outCount, but may
781 : * be less).
782 : *
783 : * Return 0 on success, -1 on failure and 1 when not all data could be sent
784 : * because the socket would block and the connection is non-blocking.
785 : *
786 : * Note that this is also responsible for consuming data from the socket
787 : * (putting it in conn->inBuffer) in any situation where we can't send
788 : * all the specified data immediately.
789 : *
790 : * If a socket-level write failure occurs, conn->write_failed is set and the
791 : * error message is saved in conn->write_err_msg, but we clear the output
792 : * buffer and return zero anyway; this is because callers should soldier on
793 : * until we have read what we can from the server and checked for an error
794 : * message. write_err_msg should be reported only when we are unable to
795 : * obtain a server error first. Much of that behavior is implemented at
796 : * lower levels, but this function deals with some edge cases.
797 : */
798 : static int
799 707086 : pqSendSome(PGconn *conn, int len)
800 : {
801 707086 : char *ptr = conn->outBuffer;
802 707086 : int remaining = conn->outCount;
803 707086 : int result = 0;
804 :
805 : /*
806 : * If we already had a write failure, we will never again try to send data
807 : * on that connection. Even if the kernel would let us, we've probably
808 : * lost message boundary sync with the server. conn->write_failed
809 : * therefore persists until the connection is reset, and we just discard
810 : * all data presented to be written. However, as long as we still have a
811 : * valid socket, we should continue to absorb data from the backend, so
812 : * that we can collect any final error messages.
813 : */
814 707086 : if (conn->write_failed)
815 : {
816 : /* conn->write_err_msg should be set up already */
817 0 : conn->outCount = 0;
818 : /* Absorb input data if any, and detect socket closure */
819 0 : if (conn->sock != PGINVALID_SOCKET)
820 : {
821 0 : if (pqReadData(conn) < 0)
822 0 : return -1;
823 : }
824 0 : return 0;
825 : }
826 :
827 707086 : if (conn->sock == PGINVALID_SOCKET)
828 : {
829 0 : conn->write_failed = true;
830 : /* Store error message in conn->write_err_msg, if possible */
831 : /* (strdup failure is OK, we'll cope later) */
832 0 : conn->write_err_msg = strdup(libpq_gettext("connection not open\n"));
833 : /* Discard queued data; no chance it'll ever be sent */
834 0 : conn->outCount = 0;
835 0 : return 0;
836 : }
837 :
838 : /* while there's still data to send */
839 1414200 : while (len > 0)
840 : {
841 : int sent;
842 :
843 : #ifndef WIN32
844 707120 : sent = pqsecure_write(conn, ptr, len);
845 : #else
846 :
847 : /*
848 : * Windows can fail on large sends, per KB article Q201213. The
849 : * failure-point appears to be different in different versions of
850 : * Windows, but 64k should always be safe.
851 : */
852 : sent = pqsecure_write(conn, ptr, Min(len, 65536));
853 : #endif
854 :
855 707120 : if (sent < 0)
856 : {
857 : /* Anything except EAGAIN/EWOULDBLOCK/EINTR is trouble */
858 40 : switch (SOCK_ERRNO)
859 : {
860 : #ifdef EAGAIN
861 40 : case EAGAIN:
862 40 : break;
863 : #endif
864 : #if defined(EWOULDBLOCK) && (!defined(EAGAIN) || (EWOULDBLOCK != EAGAIN))
865 : case EWOULDBLOCK:
866 : break;
867 : #endif
868 0 : case EINTR:
869 0 : continue;
870 :
871 0 : default:
872 : /* Discard queued data; no chance it'll ever be sent */
873 0 : conn->outCount = 0;
874 :
875 : /* Absorb input data if any, and detect socket closure */
876 0 : if (conn->sock != PGINVALID_SOCKET)
877 : {
878 0 : if (pqReadData(conn) < 0)
879 0 : return -1;
880 : }
881 :
882 : /*
883 : * Lower-level code should already have filled
884 : * conn->write_err_msg (and set conn->write_failed) or
885 : * conn->errorMessage. In the former case, we pretend
886 : * there's no problem; the write_failed condition will be
887 : * dealt with later. Otherwise, report the error now.
888 : */
889 0 : if (conn->write_failed)
890 0 : return 0;
891 : else
892 0 : return -1;
893 : }
894 : }
895 : else
896 : {
897 707080 : ptr += sent;
898 707080 : len -= sent;
899 707080 : remaining -= sent;
900 : }
901 :
902 707120 : if (len > 0)
903 : {
904 : /*
905 : * We didn't send it all, wait till we can send more.
906 : *
907 : * There are scenarios in which we can't send data because the
908 : * communications channel is full, but we cannot expect the server
909 : * to clear the channel eventually because it's blocked trying to
910 : * send data to us. (This can happen when we are sending a large
911 : * amount of COPY data, and the server has generated lots of
912 : * NOTICE responses.) To avoid a deadlock situation, we must be
913 : * prepared to accept and buffer incoming data before we try
914 : * again. Furthermore, it is possible that such incoming data
915 : * might not arrive until after we've gone to sleep. Therefore,
916 : * we wait for either read ready or write ready.
917 : *
918 : * In non-blocking mode, we don't wait here directly, but return 1
919 : * to indicate that data is still pending. The caller should wait
920 : * for both read and write ready conditions, and call
921 : * PQconsumeInput() on read ready, but just in case it doesn't, we
922 : * call pqReadData() ourselves before returning. That's not
923 : * enough if the data has not arrived yet, but it's the best we
924 : * can do, and works pretty well in practice. (The documentation
925 : * used to say that you only need to wait for write-ready, so
926 : * there are still plenty of applications like that out there.)
927 : *
928 : * Note that errors here don't result in write_failed becoming
929 : * set.
930 : */
931 40 : if (pqReadData(conn) < 0)
932 : {
933 0 : result = -1; /* error message already set up */
934 0 : break;
935 : }
936 :
937 40 : if (pqIsnonblocking(conn))
938 : {
939 6 : result = 1;
940 6 : break;
941 : }
942 :
943 34 : if (pqWait(true, true, conn))
944 : {
945 0 : result = -1;
946 0 : break;
947 : }
948 : }
949 : }
950 :
951 : /* shift the remaining contents of the buffer */
952 707086 : if (remaining > 0)
953 2044 : memmove(conn->outBuffer, ptr, remaining);
954 707086 : conn->outCount = remaining;
955 :
956 707086 : return result;
957 : }
958 :
959 :
960 : /*
961 : * pqFlush: send any data waiting in the output buffer
962 : *
963 : * Return 0 on success, -1 on failure and 1 when not all data could be sent
964 : * because the socket would block and the connection is non-blocking.
965 : * (See pqSendSome comments about how failure should be handled.)
966 : */
967 : int
968 1436172 : pqFlush(PGconn *conn)
969 : {
970 1436172 : if (conn->outCount > 0)
971 : {
972 705042 : if (conn->Pfdebug)
973 108 : fflush(conn->Pfdebug);
974 :
975 705042 : return pqSendSome(conn, conn->outCount);
976 : }
977 :
978 731130 : return 0;
979 : }
980 :
981 :
982 : /*
983 : * pqWait: wait until we can read or write the connection socket
984 : *
985 : * JAB: If SSL enabled and used and forRead, buffered bytes short-circuit the
986 : * call to select().
987 : *
988 : * We also stop waiting and return if the kernel flags an exception condition
989 : * on the socket. The actual error condition will be detected and reported
990 : * when the caller tries to read or write the socket.
991 : */
992 : int
993 950134 : pqWait(int forRead, int forWrite, PGconn *conn)
994 : {
995 950134 : return pqWaitTimed(forRead, forWrite, conn, -1);
996 : }
997 :
998 : /*
999 : * pqWaitTimed: wait, but not past end_time.
1000 : *
1001 : * Returns -1 on failure, 0 if the socket is readable/writable, 1 if it timed out.
1002 : *
1003 : * The timeout is specified by end_time, which is the int64 number of
1004 : * microseconds since the Unix epoch (that is, time_t times 1 million).
1005 : * Timeout is infinite if end_time is -1. Timeout is immediate (no blocking)
1006 : * if end_time is 0 (or indeed, any time before now).
1007 : */
1008 : int
1009 1000440 : pqWaitTimed(int forRead, int forWrite, PGconn *conn, pg_usec_time_t end_time)
1010 : {
1011 : int result;
1012 :
1013 1000440 : result = pqSocketCheck(conn, forRead, forWrite, end_time);
1014 :
1015 1000440 : if (result < 0)
1016 4 : return -1; /* errorMessage is already set */
1017 :
1018 1000436 : if (result == 0)
1019 : {
1020 0 : libpq_append_conn_error(conn, "timeout expired");
1021 0 : return 1;
1022 : }
1023 :
1024 1000436 : return 0;
1025 : }
1026 :
1027 : /*
1028 : * pqReadReady: is select() saying the file is ready to read?
1029 : * Returns -1 on failure, 0 if not ready, 1 if ready.
1030 : */
1031 : int
1032 194 : pqReadReady(PGconn *conn)
1033 : {
1034 194 : return pqSocketCheck(conn, 1, 0, 0);
1035 : }
1036 :
1037 : /*
1038 : * pqWriteReady: is select() saying the file is ready to write?
1039 : * Returns -1 on failure, 0 if not ready, 1 if ready.
1040 : */
1041 : int
1042 0 : pqWriteReady(PGconn *conn)
1043 : {
1044 0 : return pqSocketCheck(conn, 0, 1, 0);
1045 : }
1046 :
1047 : /*
1048 : * Checks a socket, using poll or select, for data to be read, written,
1049 : * or both. Returns >0 if one or more conditions are met, 0 if it timed
1050 : * out, -1 if an error occurred.
1051 : *
1052 : * If SSL is in use, the SSL buffer is checked prior to checking the socket
1053 : * for read data directly.
1054 : */
1055 : static int
1056 1000634 : pqSocketCheck(PGconn *conn, int forRead, int forWrite, pg_usec_time_t end_time)
1057 : {
1058 : int result;
1059 :
1060 1000634 : if (!conn)
1061 0 : return -1;
1062 1000634 : if (conn->sock == PGINVALID_SOCKET)
1063 : {
1064 4 : libpq_append_conn_error(conn, "invalid socket");
1065 4 : return -1;
1066 : }
1067 :
1068 : #ifdef USE_SSL
1069 : /* Check for SSL library buffering read bytes */
1070 1000630 : if (forRead && conn->ssl_in_use && pgtls_read_pending(conn))
1071 : {
1072 : /* short-circuit the select */
1073 0 : return 1;
1074 : }
1075 : #endif
1076 :
1077 : /* We will retry as long as we get EINTR */
1078 : do
1079 1000634 : result = PQsocketPoll(conn->sock, forRead, forWrite, end_time);
1080 1000634 : while (result < 0 && SOCK_ERRNO == EINTR);
1081 :
1082 1000630 : if (result < 0)
1083 : {
1084 : char sebuf[PG_STRERROR_R_BUFLEN];
1085 :
1086 0 : libpq_append_conn_error(conn, "%s() failed: %s", "select",
1087 0 : SOCK_STRERROR(SOCK_ERRNO, sebuf, sizeof(sebuf)));
1088 : }
1089 :
1090 1000630 : return result;
1091 : }
1092 :
1093 :
1094 : /*
1095 : * Check a file descriptor for read and/or write data, possibly waiting.
1096 : * If neither forRead nor forWrite are set, immediately return a timeout
1097 : * condition (without waiting). Return >0 if condition is met, 0
1098 : * if a timeout occurred, -1 if an error or interrupt occurred.
1099 : *
1100 : * The timeout is specified by end_time, which is the int64 number of
1101 : * microseconds since the Unix epoch (that is, time_t times 1 million).
1102 : * Timeout is infinite if end_time is -1. Timeout is immediate (no blocking)
1103 : * if end_time is 0 (or indeed, any time before now).
1104 : */
1105 : int
1106 1001264 : PQsocketPoll(int sock, int forRead, int forWrite, pg_usec_time_t end_time)
1107 : {
1108 : /* We use poll(2) if available, otherwise select(2) */
1109 : #ifdef HAVE_POLL
1110 : struct pollfd input_fd;
1111 : int timeout_ms;
1112 :
1113 1001264 : if (!forRead && !forWrite)
1114 0 : return 0;
1115 :
1116 1001264 : input_fd.fd = sock;
1117 1001264 : input_fd.events = POLLERR;
1118 1001264 : input_fd.revents = 0;
1119 :
1120 1001264 : if (forRead)
1121 975872 : input_fd.events |= POLLIN;
1122 1001264 : if (forWrite)
1123 25426 : input_fd.events |= POLLOUT;
1124 :
1125 : /* Compute appropriate timeout interval */
1126 1001264 : if (end_time == -1)
1127 1000412 : timeout_ms = -1;
1128 852 : else if (end_time == 0)
1129 194 : timeout_ms = 0;
1130 : else
1131 : {
1132 658 : pg_usec_time_t now = PQgetCurrentTimeUSec();
1133 :
1134 658 : if (end_time > now)
1135 658 : timeout_ms = (end_time - now) / 1000;
1136 : else
1137 0 : timeout_ms = 0;
1138 : }
1139 :
1140 1001264 : return poll(&input_fd, 1, timeout_ms);
1141 : #else /* !HAVE_POLL */
1142 :
1143 : fd_set input_mask;
1144 : fd_set output_mask;
1145 : fd_set except_mask;
1146 : struct timeval timeout;
1147 : struct timeval *ptr_timeout;
1148 :
1149 : if (!forRead && !forWrite)
1150 : return 0;
1151 :
1152 : FD_ZERO(&input_mask);
1153 : FD_ZERO(&output_mask);
1154 : FD_ZERO(&except_mask);
1155 : if (forRead)
1156 : FD_SET(sock, &input_mask);
1157 :
1158 : if (forWrite)
1159 : FD_SET(sock, &output_mask);
1160 : FD_SET(sock, &except_mask);
1161 :
1162 : /* Compute appropriate timeout interval */
1163 : if (end_time == -1)
1164 : ptr_timeout = NULL;
1165 : else if (end_time == 0)
1166 : {
1167 : timeout.tv_sec = 0;
1168 : timeout.tv_usec = 0;
1169 : ptr_timeout = &timeout;
1170 : }
1171 : else
1172 : {
1173 : pg_usec_time_t now = PQgetCurrentTimeUSec();
1174 :
1175 : if (end_time > now)
1176 : {
1177 : timeout.tv_sec = (end_time - now) / 1000000;
1178 : timeout.tv_usec = (end_time - now) % 1000000;
1179 : }
1180 : else
1181 : {
1182 : timeout.tv_sec = 0;
1183 : timeout.tv_usec = 0;
1184 : }
1185 : ptr_timeout = &timeout;
1186 : }
1187 :
1188 : return select(sock + 1, &input_mask, &output_mask,
1189 : &except_mask, ptr_timeout);
1190 : #endif /* HAVE_POLL */
1191 : }
1192 :
1193 : /*
1194 : * PQgetCurrentTimeUSec: get current time with microsecond precision
1195 : *
1196 : * This provides a platform-independent way of producing a reference
1197 : * value for PQsocketPoll's timeout parameter.
1198 : */
1199 : pg_usec_time_t
1200 1296 : PQgetCurrentTimeUSec(void)
1201 : {
1202 : struct timeval tval;
1203 :
1204 1296 : gettimeofday(&tval, NULL);
1205 1296 : return (pg_usec_time_t) tval.tv_sec * 1000000 + tval.tv_usec;
1206 : }
1207 :
1208 :
1209 : /*
1210 : * A couple of "miscellaneous" multibyte related functions. They used
1211 : * to be in fe-print.c but that file is doomed.
1212 : */
1213 :
1214 : /*
1215 : * Returns the byte length of the character beginning at s, using the
1216 : * specified encoding.
1217 : *
1218 : * Caution: when dealing with text that is not certainly valid in the
1219 : * specified encoding, the result may exceed the actual remaining
1220 : * string length. Callers that are not prepared to deal with that
1221 : * should use PQmblenBounded() instead.
1222 : */
1223 : int
1224 50912334 : PQmblen(const char *s, int encoding)
1225 : {
1226 50912334 : return pg_encoding_mblen(encoding, s);
1227 : }
1228 :
1229 : /*
1230 : * Returns the byte length of the character beginning at s, using the
1231 : * specified encoding; but not more than the distance to end of string.
1232 : */
1233 : int
1234 741830 : PQmblenBounded(const char *s, int encoding)
1235 : {
1236 741830 : return strnlen(s, pg_encoding_mblen(encoding, s));
1237 : }
1238 :
1239 : /*
1240 : * Returns the display length of the character beginning at s, using the
1241 : * specified encoding.
1242 : */
1243 : int
1244 50913556 : PQdsplen(const char *s, int encoding)
1245 : {
1246 50913556 : return pg_encoding_dsplen(encoding, s);
1247 : }
1248 :
1249 : /*
1250 : * Get encoding id from environment variable PGCLIENTENCODING.
1251 : */
1252 : int
1253 18664 : PQenv2encoding(void)
1254 : {
1255 : char *str;
1256 18664 : int encoding = PG_SQL_ASCII;
1257 :
1258 18664 : str = getenv("PGCLIENTENCODING");
1259 18664 : if (str && *str != '\0')
1260 : {
1261 12 : encoding = pg_char_to_encoding(str);
1262 12 : if (encoding < 0)
1263 0 : encoding = PG_SQL_ASCII;
1264 : }
1265 18664 : return encoding;
1266 : }
1267 :
1268 :
1269 : #ifdef ENABLE_NLS
1270 :
1271 : static void
1272 184812 : libpq_binddomain(void)
1273 : {
1274 : /*
1275 : * At least on Windows, there are gettext implementations that fail if
1276 : * multiple threads call bindtextdomain() concurrently. Use a mutex and
1277 : * flag variable to ensure that we call it just once per process. It is
1278 : * not known that similar bugs exist on non-Windows platforms, but we
1279 : * might as well do it the same way everywhere.
1280 : */
1281 : static volatile bool already_bound = false;
1282 : static pthread_mutex_t binddomain_mutex = PTHREAD_MUTEX_INITIALIZER;
1283 :
1284 184812 : if (!already_bound)
1285 : {
1286 : /* bindtextdomain() does not preserve errno */
1287 : #ifdef WIN32
1288 : int save_errno = GetLastError();
1289 : #else
1290 22764 : int save_errno = errno;
1291 : #endif
1292 :
1293 22764 : (void) pthread_mutex_lock(&binddomain_mutex);
1294 :
1295 22764 : if (!already_bound)
1296 : {
1297 : const char *ldir;
1298 :
1299 : /*
1300 : * No relocatable lookup here because the calling executable could
1301 : * be anywhere
1302 : */
1303 22764 : ldir = getenv("PGLOCALEDIR");
1304 22764 : if (!ldir)
1305 216 : ldir = LOCALEDIR;
1306 22764 : bindtextdomain(PG_TEXTDOMAIN("libpq"), ldir);
1307 22764 : already_bound = true;
1308 : }
1309 :
1310 22764 : (void) pthread_mutex_unlock(&binddomain_mutex);
1311 :
1312 : #ifdef WIN32
1313 : SetLastError(save_errno);
1314 : #else
1315 22764 : errno = save_errno;
1316 : #endif
1317 : }
1318 184812 : }
1319 :
1320 : char *
1321 184798 : libpq_gettext(const char *msgid)
1322 : {
1323 184798 : libpq_binddomain();
1324 184798 : return dgettext(PG_TEXTDOMAIN("libpq"), msgid);
1325 : }
1326 :
1327 : char *
1328 14 : libpq_ngettext(const char *msgid, const char *msgid_plural, unsigned long n)
1329 : {
1330 14 : libpq_binddomain();
1331 14 : return dngettext(PG_TEXTDOMAIN("libpq"), msgid, msgid_plural, n);
1332 : }
1333 :
1334 : #endif /* ENABLE_NLS */
1335 :
1336 :
1337 : /*
1338 : * Append a formatted string to the given buffer, after translating it. A
1339 : * newline is automatically appended; the format should not end with a
1340 : * newline.
1341 : */
1342 : void
1343 54 : libpq_append_error(PQExpBuffer errorMessage, const char *fmt,...)
1344 : {
1345 54 : int save_errno = errno;
1346 : bool done;
1347 : va_list args;
1348 :
1349 : Assert(fmt[strlen(fmt) - 1] != '\n');
1350 :
1351 54 : if (PQExpBufferBroken(errorMessage))
1352 0 : return; /* already failed */
1353 :
1354 : /* Loop in case we have to retry after enlarging the buffer. */
1355 : do
1356 : {
1357 54 : errno = save_errno;
1358 54 : va_start(args, fmt);
1359 54 : done = appendPQExpBufferVA(errorMessage, libpq_gettext(fmt), args);
1360 54 : va_end(args);
1361 54 : } while (!done);
1362 :
1363 54 : appendPQExpBufferChar(errorMessage, '\n');
1364 : }
1365 :
1366 : /*
1367 : * Append a formatted string to the error message buffer of the given
1368 : * connection, after translating it. A newline is automatically appended; the
1369 : * format should not end with a newline.
1370 : */
1371 : void
1372 950 : libpq_append_conn_error(PGconn *conn, const char *fmt,...)
1373 : {
1374 950 : int save_errno = errno;
1375 : bool done;
1376 : va_list args;
1377 :
1378 : Assert(fmt[strlen(fmt) - 1] != '\n');
1379 :
1380 950 : if (PQExpBufferBroken(&conn->errorMessage))
1381 0 : return; /* already failed */
1382 :
1383 : /* Loop in case we have to retry after enlarging the buffer. */
1384 : do
1385 : {
1386 958 : errno = save_errno;
1387 958 : va_start(args, fmt);
1388 958 : done = appendPQExpBufferVA(&conn->errorMessage, libpq_gettext(fmt), args);
1389 958 : va_end(args);
1390 958 : } while (!done);
1391 :
1392 950 : appendPQExpBufferChar(&conn->errorMessage, '\n');
1393 : }
|
