/
pqcomm.c
2084 lines (1841 loc) · 52.9 KB
/
pqcomm.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*-------------------------------------------------------------------------
*
* pqcomm.c
* Communication functions between the Frontend and the Backend
*
* These routines handle the low-level details of communication between
* frontend and backend. They just shove data across the communication
* channel, and are ignorant of the semantics of the data.
*
* To emit an outgoing message, use the routines in pqformat.c to construct
* the message in a buffer and then emit it in one call to pq_putmessage.
* There are no functions to send raw bytes or partial messages; this
* ensures that the channel will not be clogged by an incomplete message if
* execution is aborted by ereport(ERROR) partway through the message.
*
* At one time, libpq was shared between frontend and backend, but now
* the backend's "backend/libpq" is quite separate from "interfaces/libpq".
* All that remains is similarities of names to trap the unwary...
*
* Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/backend/libpq/pqcomm.c
*
*-------------------------------------------------------------------------
*/
/*------------------------
* INTERFACE ROUTINES
*
* setup/teardown:
* ListenServerPort - Open postmaster's server port
* AcceptConnection - Accept new connection with client
* TouchSocketFiles - Protect socket files against /tmp cleaners
* pq_init - initialize libpq at backend startup
* socket_comm_reset - reset libpq during error recovery
* socket_close - shutdown libpq at backend exit
*
* low-level I/O:
* pq_getbytes - get a known number of bytes from connection
* pq_getmessage - get a message with length word from connection
* pq_getbyte - get next byte from connection
* pq_peekbyte - peek at next byte from connection
* pq_flush - flush pending output
* pq_flush_if_writable - flush pending output if writable without blocking
* pq_getbyte_if_available - get a byte if available without blocking
*
* message-level I/O
* pq_putmessage - send a normal message (suppressed in COPY OUT mode)
* pq_putmessage_noblock - buffer a normal message (suppressed in COPY OUT)
*
*------------------------
*/
#include "postgres.h"
#ifdef HAVE_POLL_H
#include <poll.h>
#endif
#include <signal.h>
#include <fcntl.h>
#include <grp.h>
#include <unistd.h>
#include <sys/file.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <netdb.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <utime.h>
#ifdef WIN32
#include <mstcpip.h>
#endif
#include "common/ip.h"
#include "libpq/libpq.h"
#include "miscadmin.h"
#include "port/pg_bswap.h"
#include "storage/ipc.h"
#include "utils/guc_hooks.h"
#include "utils/memutils.h"
/*
* Cope with the various platform-specific ways to spell TCP keepalive socket
* options. This doesn't cover Windows, which as usual does its own thing.
*/
#if defined(TCP_KEEPIDLE)
/* TCP_KEEPIDLE is the name of this option on Linux and *BSD */
#define PG_TCP_KEEPALIVE_IDLE TCP_KEEPIDLE
#define PG_TCP_KEEPALIVE_IDLE_STR "TCP_KEEPIDLE"
#elif defined(TCP_KEEPALIVE_THRESHOLD)
/* TCP_KEEPALIVE_THRESHOLD is the name of this option on Solaris >= 11 */
#define PG_TCP_KEEPALIVE_IDLE TCP_KEEPALIVE_THRESHOLD
#define PG_TCP_KEEPALIVE_IDLE_STR "TCP_KEEPALIVE_THRESHOLD"
#elif defined(TCP_KEEPALIVE) && defined(__darwin__)
/* TCP_KEEPALIVE is the name of this option on macOS */
/* Caution: Solaris has this symbol but it means something different */
#define PG_TCP_KEEPALIVE_IDLE TCP_KEEPALIVE
#define PG_TCP_KEEPALIVE_IDLE_STR "TCP_KEEPALIVE"
#endif
/*
* Configuration options
*/
int Unix_socket_permissions;
char *Unix_socket_group;
/* Where the Unix socket files are (list of palloc'd strings) */
static List *sock_paths = NIL;
/*
* Buffers for low-level I/O.
*
* The receive buffer is fixed size. Send buffer is usually 8k, but can be
* enlarged by pq_putmessage_noblock() if the message doesn't fit otherwise.
*/
#define PQ_SEND_BUFFER_SIZE 8192
#define PQ_RECV_BUFFER_SIZE 8192
static char *PqSendBuffer;
static int PqSendBufferSize; /* Size send buffer */
static size_t PqSendPointer; /* Next index to store a byte in PqSendBuffer */
static size_t PqSendStart; /* Next index to send a byte in PqSendBuffer */
static char PqRecvBuffer[PQ_RECV_BUFFER_SIZE];
static int PqRecvPointer; /* Next index to read a byte from PqRecvBuffer */
static int PqRecvLength; /* End of data available in PqRecvBuffer */
/*
* Message status
*/
static bool PqCommBusy; /* busy sending data to the client */
static bool PqCommReadingMsg; /* in the middle of reading a message */
/* Internal functions */
static void socket_comm_reset(void);
static void socket_close(int code, Datum arg);
static void socket_set_nonblocking(bool nonblocking);
static int socket_flush(void);
static int socket_flush_if_writable(void);
static bool socket_is_send_pending(void);
static int socket_putmessage(char msgtype, const char *s, size_t len);
static void socket_putmessage_noblock(char msgtype, const char *s, size_t len);
static inline int internal_putbytes(const char *s, size_t len);
static inline int internal_flush(void);
static pg_noinline int internal_flush_buffer(const char *buf, size_t *start,
size_t *end);
static int Lock_AF_UNIX(const char *unixSocketDir, const char *unixSocketPath);
static int Setup_AF_UNIX(const char *sock_path);
static const PQcommMethods PqCommSocketMethods = {
.comm_reset = socket_comm_reset,
.flush = socket_flush,
.flush_if_writable = socket_flush_if_writable,
.is_send_pending = socket_is_send_pending,
.putmessage = socket_putmessage,
.putmessage_noblock = socket_putmessage_noblock
};
const PQcommMethods *PqCommMethods = &PqCommSocketMethods;
WaitEventSet *FeBeWaitSet;
/* --------------------------------
* pq_init - initialize libpq at backend startup
* --------------------------------
*/
Port *
pq_init(ClientSocket *client_sock)
{
Port *port;
int socket_pos PG_USED_FOR_ASSERTS_ONLY;
int latch_pos PG_USED_FOR_ASSERTS_ONLY;
/* allocate the Port struct and copy the ClientSocket contents to it */
port = palloc0(sizeof(Port));
port->sock = client_sock->sock;
memcpy(&port->raddr.addr, &client_sock->raddr.addr, client_sock->raddr.salen);
port->raddr.salen = client_sock->raddr.salen;
/* fill in the server (local) address */
port->laddr.salen = sizeof(port->laddr.addr);
if (getsockname(port->sock,
(struct sockaddr *) &port->laddr.addr,
&port->laddr.salen) < 0)
{
ereport(FATAL,
(errmsg("%s() failed: %m", "getsockname")));
}
/* select NODELAY and KEEPALIVE options if it's a TCP connection */
if (port->laddr.addr.ss_family != AF_UNIX)
{
int on;
#ifdef WIN32
int oldopt;
int optlen;
int newopt;
#endif
#ifdef TCP_NODELAY
on = 1;
if (setsockopt(port->sock, IPPROTO_TCP, TCP_NODELAY,
(char *) &on, sizeof(on)) < 0)
{
ereport(FATAL,
(errmsg("%s(%s) failed: %m", "setsockopt", "TCP_NODELAY")));
}
#endif
on = 1;
if (setsockopt(port->sock, SOL_SOCKET, SO_KEEPALIVE,
(char *) &on, sizeof(on)) < 0)
{
ereport(FATAL,
(errmsg("%s(%s) failed: %m", "setsockopt", "SO_KEEPALIVE")));
}
#ifdef WIN32
/*
* This is a Win32 socket optimization. The OS send buffer should be
* large enough to send the whole Postgres send buffer in one go, or
* performance suffers. The Postgres send buffer can be enlarged if a
* very large message needs to be sent, but we won't attempt to
* enlarge the OS buffer if that happens, so somewhat arbitrarily
* ensure that the OS buffer is at least PQ_SEND_BUFFER_SIZE * 4.
* (That's 32kB with the current default).
*
* The default OS buffer size used to be 8kB in earlier Windows
* versions, but was raised to 64kB in Windows 2012. So it shouldn't
* be necessary to change it in later versions anymore. Changing it
* unnecessarily can even reduce performance, because setting
* SO_SNDBUF in the application disables the "dynamic send buffering"
* feature that was introduced in Windows 7. So before fiddling with
* SO_SNDBUF, check if the current buffer size is already large enough
* and only increase it if necessary.
*
* See https://support.microsoft.com/kb/823764/EN-US/ and
* https://msdn.microsoft.com/en-us/library/bb736549%28v=vs.85%29.aspx
*/
optlen = sizeof(oldopt);
if (getsockopt(port->sock, SOL_SOCKET, SO_SNDBUF, (char *) &oldopt,
&optlen) < 0)
{
ereport(FATAL,
(errmsg("%s(%s) failed: %m", "getsockopt", "SO_SNDBUF")));
}
newopt = PQ_SEND_BUFFER_SIZE * 4;
if (oldopt < newopt)
{
if (setsockopt(port->sock, SOL_SOCKET, SO_SNDBUF, (char *) &newopt,
sizeof(newopt)) < 0)
{
ereport(FATAL,
(errmsg("%s(%s) failed: %m", "setsockopt", "SO_SNDBUF")));
}
}
#endif
/*
* Also apply the current keepalive parameters. If we fail to set a
* parameter, don't error out, because these aren't universally
* supported. (Note: you might think we need to reset the GUC
* variables to 0 in such a case, but it's not necessary because the
* show hooks for these variables report the truth anyway.)
*/
(void) pq_setkeepalivesidle(tcp_keepalives_idle, port);
(void) pq_setkeepalivesinterval(tcp_keepalives_interval, port);
(void) pq_setkeepalivescount(tcp_keepalives_count, port);
(void) pq_settcpusertimeout(tcp_user_timeout, port);
}
/* initialize state variables */
PqSendBufferSize = PQ_SEND_BUFFER_SIZE;
PqSendBuffer = MemoryContextAlloc(TopMemoryContext, PqSendBufferSize);
PqSendPointer = PqSendStart = PqRecvPointer = PqRecvLength = 0;
PqCommBusy = false;
PqCommReadingMsg = false;
/* set up process-exit hook to close the socket */
on_proc_exit(socket_close, 0);
/*
* In backends (as soon as forked) we operate the underlying socket in
* nonblocking mode and use latches to implement blocking semantics if
* needed. That allows us to provide safely interruptible reads and
* writes.
*/
#ifndef WIN32
if (!pg_set_noblock(port->sock))
ereport(FATAL,
(errmsg("could not set socket to nonblocking mode: %m")));
#endif
#ifndef WIN32
/* Don't give the socket to any subprograms we execute. */
if (fcntl(port->sock, F_SETFD, FD_CLOEXEC) < 0)
elog(FATAL, "fcntl(F_SETFD) failed on socket: %m");
#endif
FeBeWaitSet = CreateWaitEventSet(NULL, FeBeWaitSetNEvents);
socket_pos = AddWaitEventToSet(FeBeWaitSet, WL_SOCKET_WRITEABLE,
port->sock, NULL, NULL);
latch_pos = AddWaitEventToSet(FeBeWaitSet, WL_LATCH_SET, PGINVALID_SOCKET,
MyLatch, NULL);
AddWaitEventToSet(FeBeWaitSet, WL_POSTMASTER_DEATH, PGINVALID_SOCKET,
NULL, NULL);
/*
* The event positions match the order we added them, but let's sanity
* check them to be sure.
*/
Assert(socket_pos == FeBeWaitSetSocketPos);
Assert(latch_pos == FeBeWaitSetLatchPos);
return port;
}
/* --------------------------------
* socket_comm_reset - reset libpq during error recovery
*
* This is called from error recovery at the outer idle loop. It's
* just to get us out of trouble if we somehow manage to elog() from
* inside a pqcomm.c routine (which ideally will never happen, but...)
* --------------------------------
*/
static void
socket_comm_reset(void)
{
/* Do not throw away pending data, but do reset the busy flag */
PqCommBusy = false;
}
/* --------------------------------
* socket_close - shutdown libpq at backend exit
*
* This is the one pg_on_exit_callback in place during BackendInitialize().
* That function's unusual signal handling constrains that this callback be
* safe to run at any instant.
* --------------------------------
*/
static void
socket_close(int code, Datum arg)
{
/* Nothing to do in a standalone backend, where MyProcPort is NULL. */
if (MyProcPort != NULL)
{
#ifdef ENABLE_GSS
/*
* Shutdown GSSAPI layer. This section does nothing when interrupting
* BackendInitialize(), because pg_GSS_recvauth() makes first use of
* "ctx" and "cred".
*
* Note that we don't bother to free MyProcPort->gss, since we're
* about to exit anyway.
*/
if (MyProcPort->gss)
{
OM_uint32 min_s;
if (MyProcPort->gss->ctx != GSS_C_NO_CONTEXT)
gss_delete_sec_context(&min_s, &MyProcPort->gss->ctx, NULL);
if (MyProcPort->gss->cred != GSS_C_NO_CREDENTIAL)
gss_release_cred(&min_s, &MyProcPort->gss->cred);
}
#endif /* ENABLE_GSS */
/*
* Cleanly shut down SSL layer. Nowhere else does a postmaster child
* call this, so this is safe when interrupting BackendInitialize().
*/
secure_close(MyProcPort);
/*
* Formerly we did an explicit close() here, but it seems better to
* leave the socket open until the process dies. This allows clients
* to perform a "synchronous close" if they care --- wait till the
* transport layer reports connection closure, and you can be sure the
* backend has exited.
*
* We do set sock to PGINVALID_SOCKET to prevent any further I/O,
* though.
*/
MyProcPort->sock = PGINVALID_SOCKET;
}
}
/* --------------------------------
* Postmaster functions to handle sockets.
* --------------------------------
*/
/*
* ListenServerPort -- open a "listening" port to accept connections.
*
* family should be AF_UNIX or AF_UNSPEC; portNumber is the port number.
* For AF_UNIX ports, hostName should be NULL and unixSocketDir must be
* specified. For TCP ports, hostName is either NULL for all interfaces or
* the interface to listen on, and unixSocketDir is ignored (can be NULL).
*
* Successfully opened sockets are appended to the ListenSockets[] array. On
* entry, *NumListenSockets holds the number of elements currently in the
* array, and it is updated to reflect the opened sockets. MaxListen is the
* allocated size of the array.
*
* RETURNS: STATUS_OK or STATUS_ERROR
*/
int
ListenServerPort(int family, const char *hostName, unsigned short portNumber,
const char *unixSocketDir,
pgsocket ListenSockets[], int *NumListenSockets, int MaxListen)
{
pgsocket fd;
int err;
int maxconn;
int ret;
char portNumberStr[32];
const char *familyDesc;
char familyDescBuf[64];
const char *addrDesc;
char addrBuf[NI_MAXHOST];
char *service;
struct addrinfo *addrs = NULL,
*addr;
struct addrinfo hint;
int added = 0;
char unixSocketPath[MAXPGPATH];
#if !defined(WIN32) || defined(IPV6_V6ONLY)
int one = 1;
#endif
/* Initialize hint structure */
MemSet(&hint, 0, sizeof(hint));
hint.ai_family = family;
hint.ai_flags = AI_PASSIVE;
hint.ai_socktype = SOCK_STREAM;
if (family == AF_UNIX)
{
/*
* Create unixSocketPath from portNumber and unixSocketDir and lock
* that file path
*/
UNIXSOCK_PATH(unixSocketPath, portNumber, unixSocketDir);
if (strlen(unixSocketPath) >= UNIXSOCK_PATH_BUFLEN)
{
ereport(LOG,
(errmsg("Unix-domain socket path \"%s\" is too long (maximum %d bytes)",
unixSocketPath,
(int) (UNIXSOCK_PATH_BUFLEN - 1))));
return STATUS_ERROR;
}
if (Lock_AF_UNIX(unixSocketDir, unixSocketPath) != STATUS_OK)
return STATUS_ERROR;
service = unixSocketPath;
}
else
{
snprintf(portNumberStr, sizeof(portNumberStr), "%d", portNumber);
service = portNumberStr;
}
ret = pg_getaddrinfo_all(hostName, service, &hint, &addrs);
if (ret || !addrs)
{
if (hostName)
ereport(LOG,
(errmsg("could not translate host name \"%s\", service \"%s\" to address: %s",
hostName, service, gai_strerror(ret))));
else
ereport(LOG,
(errmsg("could not translate service \"%s\" to address: %s",
service, gai_strerror(ret))));
if (addrs)
pg_freeaddrinfo_all(hint.ai_family, addrs);
return STATUS_ERROR;
}
for (addr = addrs; addr; addr = addr->ai_next)
{
if (family != AF_UNIX && addr->ai_family == AF_UNIX)
{
/*
* Only set up a unix domain socket when they really asked for it.
* The service/port is different in that case.
*/
continue;
}
/* See if there is still room to add 1 more socket. */
if (*NumListenSockets == MaxListen)
{
ereport(LOG,
(errmsg("could not bind to all requested addresses: MAXLISTEN (%d) exceeded",
MaxListen)));
break;
}
/* set up address family name for log messages */
switch (addr->ai_family)
{
case AF_INET:
familyDesc = _("IPv4");
break;
case AF_INET6:
familyDesc = _("IPv6");
break;
case AF_UNIX:
familyDesc = _("Unix");
break;
default:
snprintf(familyDescBuf, sizeof(familyDescBuf),
_("unrecognized address family %d"),
addr->ai_family);
familyDesc = familyDescBuf;
break;
}
/* set up text form of address for log messages */
if (addr->ai_family == AF_UNIX)
addrDesc = unixSocketPath;
else
{
pg_getnameinfo_all((const struct sockaddr_storage *) addr->ai_addr,
addr->ai_addrlen,
addrBuf, sizeof(addrBuf),
NULL, 0,
NI_NUMERICHOST);
addrDesc = addrBuf;
}
if ((fd = socket(addr->ai_family, SOCK_STREAM, 0)) == PGINVALID_SOCKET)
{
ereport(LOG,
(errcode_for_socket_access(),
/* translator: first %s is IPv4, IPv6, or Unix */
errmsg("could not create %s socket for address \"%s\": %m",
familyDesc, addrDesc)));
continue;
}
#ifndef WIN32
/* Don't give the listen socket to any subprograms we execute. */
if (fcntl(fd, F_SETFD, FD_CLOEXEC) < 0)
elog(FATAL, "fcntl(F_SETFD) failed on socket: %m");
/*
* Without the SO_REUSEADDR flag, a new postmaster can't be started
* right away after a stop or crash, giving "address already in use"
* error on TCP ports.
*
* On win32, however, this behavior only happens if the
* SO_EXCLUSIVEADDRUSE is set. With SO_REUSEADDR, win32 allows
* multiple servers to listen on the same address, resulting in
* unpredictable behavior. With no flags at all, win32 behaves as Unix
* with SO_REUSEADDR.
*/
if (addr->ai_family != AF_UNIX)
{
if ((setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
(char *) &one, sizeof(one))) == -1)
{
ereport(LOG,
(errcode_for_socket_access(),
/* translator: third %s is IPv4, IPv6, or Unix */
errmsg("%s(%s) failed for %s address \"%s\": %m",
"setsockopt", "SO_REUSEADDR",
familyDesc, addrDesc)));
closesocket(fd);
continue;
}
}
#endif
#ifdef IPV6_V6ONLY
if (addr->ai_family == AF_INET6)
{
if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY,
(char *) &one, sizeof(one)) == -1)
{
ereport(LOG,
(errcode_for_socket_access(),
/* translator: third %s is IPv4, IPv6, or Unix */
errmsg("%s(%s) failed for %s address \"%s\": %m",
"setsockopt", "IPV6_V6ONLY",
familyDesc, addrDesc)));
closesocket(fd);
continue;
}
}
#endif
/*
* Note: This might fail on some OS's, like Linux older than
* 2.4.21-pre3, that don't have the IPV6_V6ONLY socket option, and map
* ipv4 addresses to ipv6. It will show ::ffff:ipv4 for all ipv4
* connections.
*/
err = bind(fd, addr->ai_addr, addr->ai_addrlen);
if (err < 0)
{
int saved_errno = errno;
ereport(LOG,
(errcode_for_socket_access(),
/* translator: first %s is IPv4, IPv6, or Unix */
errmsg("could not bind %s address \"%s\": %m",
familyDesc, addrDesc),
saved_errno == EADDRINUSE ?
(addr->ai_family == AF_UNIX ?
errhint("Is another postmaster already running on port %d?",
(int) portNumber) :
errhint("Is another postmaster already running on port %d?"
" If not, wait a few seconds and retry.",
(int) portNumber)) : 0));
closesocket(fd);
continue;
}
if (addr->ai_family == AF_UNIX)
{
if (Setup_AF_UNIX(service) != STATUS_OK)
{
closesocket(fd);
break;
}
}
/*
* Select appropriate accept-queue length limit. It seems reasonable
* to use a value similar to the maximum number of child processes
* that the postmaster will permit.
*/
maxconn = MaxConnections * 2;
err = listen(fd, maxconn);
if (err < 0)
{
ereport(LOG,
(errcode_for_socket_access(),
/* translator: first %s is IPv4, IPv6, or Unix */
errmsg("could not listen on %s address \"%s\": %m",
familyDesc, addrDesc)));
closesocket(fd);
continue;
}
if (addr->ai_family == AF_UNIX)
ereport(LOG,
(errmsg("listening on Unix socket \"%s\"",
addrDesc)));
else
ereport(LOG,
/* translator: first %s is IPv4 or IPv6 */
(errmsg("listening on %s address \"%s\", port %d",
familyDesc, addrDesc, (int) portNumber)));
ListenSockets[*NumListenSockets] = fd;
(*NumListenSockets)++;
added++;
}
pg_freeaddrinfo_all(hint.ai_family, addrs);
if (!added)
return STATUS_ERROR;
return STATUS_OK;
}
/*
* Lock_AF_UNIX -- configure unix socket file path
*/
static int
Lock_AF_UNIX(const char *unixSocketDir, const char *unixSocketPath)
{
/* no lock file for abstract sockets */
if (unixSocketPath[0] == '@')
return STATUS_OK;
/*
* Grab an interlock file associated with the socket file.
*
* Note: there are two reasons for using a socket lock file, rather than
* trying to interlock directly on the socket itself. First, it's a lot
* more portable, and second, it lets us remove any pre-existing socket
* file without race conditions.
*/
CreateSocketLockFile(unixSocketPath, true, unixSocketDir);
/*
* Once we have the interlock, we can safely delete any pre-existing
* socket file to avoid failure at bind() time.
*/
(void) unlink(unixSocketPath);
/*
* Remember socket file pathnames for later maintenance.
*/
sock_paths = lappend(sock_paths, pstrdup(unixSocketPath));
return STATUS_OK;
}
/*
* Setup_AF_UNIX -- configure unix socket permissions
*/
static int
Setup_AF_UNIX(const char *sock_path)
{
/* no file system permissions for abstract sockets */
if (sock_path[0] == '@')
return STATUS_OK;
/*
* Fix socket ownership/permission if requested. Note we must do this
* before we listen() to avoid a window where unwanted connections could
* get accepted.
*/
Assert(Unix_socket_group);
if (Unix_socket_group[0] != '\0')
{
#ifdef WIN32
elog(WARNING, "configuration item unix_socket_group is not supported on this platform");
#else
char *endptr;
unsigned long val;
gid_t gid;
val = strtoul(Unix_socket_group, &endptr, 10);
if (*endptr == '\0')
{ /* numeric group id */
gid = val;
}
else
{ /* convert group name to id */
struct group *gr;
gr = getgrnam(Unix_socket_group);
if (!gr)
{
ereport(LOG,
(errmsg("group \"%s\" does not exist",
Unix_socket_group)));
return STATUS_ERROR;
}
gid = gr->gr_gid;
}
if (chown(sock_path, -1, gid) == -1)
{
ereport(LOG,
(errcode_for_file_access(),
errmsg("could not set group of file \"%s\": %m",
sock_path)));
return STATUS_ERROR;
}
#endif
}
if (chmod(sock_path, Unix_socket_permissions) == -1)
{
ereport(LOG,
(errcode_for_file_access(),
errmsg("could not set permissions of file \"%s\": %m",
sock_path)));
return STATUS_ERROR;
}
return STATUS_OK;
}
/*
* AcceptConnection -- accept a new connection with client using
* server port. Fills *client_sock with the FD and endpoint info
* of the new connection.
*
* ASSUME: that this doesn't need to be non-blocking because
* the Postmaster waits for the socket to be ready to accept().
*
* RETURNS: STATUS_OK or STATUS_ERROR
*/
int
AcceptConnection(pgsocket server_fd, ClientSocket *client_sock)
{
/* accept connection and fill in the client (remote) address */
client_sock->raddr.salen = sizeof(client_sock->raddr.addr);
if ((client_sock->sock = accept(server_fd,
(struct sockaddr *) &client_sock->raddr.addr,
&client_sock->raddr.salen)) == PGINVALID_SOCKET)
{
ereport(LOG,
(errcode_for_socket_access(),
errmsg("could not accept new connection: %m")));
/*
* If accept() fails then postmaster.c will still see the server
* socket as read-ready, and will immediately try again. To avoid
* uselessly sucking lots of CPU, delay a bit before trying again.
* (The most likely reason for failure is being out of kernel file
* table slots; we can do little except hope some will get freed up.)
*/
pg_usleep(100000L); /* wait 0.1 sec */
return STATUS_ERROR;
}
return STATUS_OK;
}
/*
* TouchSocketFiles -- mark socket files as recently accessed
*
* This routine should be called every so often to ensure that the socket
* files have a recent mod date (ordinary operations on sockets usually won't
* change the mod date). That saves them from being removed by
* overenthusiastic /tmp-directory-cleaner daemons. (Another reason we should
* never have put the socket file in /tmp...)
*/
void
TouchSocketFiles(void)
{
ListCell *l;
/* Loop through all created sockets... */
foreach(l, sock_paths)
{
char *sock_path = (char *) lfirst(l);
/* Ignore errors; there's no point in complaining */
(void) utime(sock_path, NULL);
}
}
/*
* RemoveSocketFiles -- unlink socket files at postmaster shutdown
*/
void
RemoveSocketFiles(void)
{
ListCell *l;
/* Loop through all created sockets... */
foreach(l, sock_paths)
{
char *sock_path = (char *) lfirst(l);
/* Ignore any error. */
(void) unlink(sock_path);
}
/* Since we're about to exit, no need to reclaim storage */
sock_paths = NIL;
}
/* --------------------------------
* Low-level I/O routines begin here.
*
* These routines communicate with a frontend client across a connection
* already established by the preceding routines.
* --------------------------------
*/
/* --------------------------------
* socket_set_nonblocking - set socket blocking/non-blocking
*
* Sets the socket non-blocking if nonblocking is true, or sets it
* blocking otherwise.
* --------------------------------
*/
static void
socket_set_nonblocking(bool nonblocking)
{
if (MyProcPort == NULL)
ereport(ERROR,
(errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST),
errmsg("there is no client connection")));
MyProcPort->noblock = nonblocking;
}
/* --------------------------------
* pq_recvbuf - load some bytes into the input buffer
*
* returns 0 if OK, EOF if trouble
* --------------------------------
*/
static int
pq_recvbuf(void)
{
if (PqRecvPointer > 0)
{
if (PqRecvLength > PqRecvPointer)
{
/* still some unread data, left-justify it in the buffer */
memmove(PqRecvBuffer, PqRecvBuffer + PqRecvPointer,
PqRecvLength - PqRecvPointer);
PqRecvLength -= PqRecvPointer;
PqRecvPointer = 0;
}
else
PqRecvLength = PqRecvPointer = 0;
}
/* Ensure that we're in blocking mode */
socket_set_nonblocking(false);
/* Can fill buffer from PqRecvLength and upwards */
for (;;)
{
int r;
errno = 0;
r = secure_read(MyProcPort, PqRecvBuffer + PqRecvLength,
PQ_RECV_BUFFER_SIZE - PqRecvLength);
if (r < 0)
{
if (errno == EINTR)
continue; /* Ok if interrupted */
/*
* Careful: an ereport() that tries to write to the client would
* cause recursion to here, leading to stack overflow and core
* dump! This message must go *only* to the postmaster log.
*
* If errno is zero, assume it's EOF and let the caller complain.
*/
if (errno != 0)
ereport(COMMERROR,
(errcode_for_socket_access(),
errmsg("could not receive data from client: %m")));
return EOF;
}
if (r == 0)
{
/*
* EOF detected. We used to write a log message here, but it's
* better to expect the ultimate caller to do that.
*/
return EOF;
}
/* r contains number of bytes read, so just incr length */
PqRecvLength += r;
return 0;
}
}
/* --------------------------------
* pq_getbyte - get a single byte from connection, or return EOF
* --------------------------------
*/
int
pq_getbyte(void)
{
Assert(PqCommReadingMsg);
while (PqRecvPointer >= PqRecvLength)
{
if (pq_recvbuf()) /* If nothing in buffer, then recv some */
return EOF; /* Failed to recv data */
}
return (unsigned char) PqRecvBuffer[PqRecvPointer++];
}
/* --------------------------------
* pq_peekbyte - peek at next byte from connection
*
* Same as pq_getbyte() except we don't advance the pointer.
* --------------------------------
*/
int
pq_peekbyte(void)
{
Assert(PqCommReadingMsg);
while (PqRecvPointer >= PqRecvLength)
{
if (pq_recvbuf()) /* If nothing in buffer, then recv some */
return EOF; /* Failed to recv data */
}
return (unsigned char) PqRecvBuffer[PqRecvPointer];
}
/* --------------------------------
* pq_getbyte_if_available - get a single byte from connection,
* if available
*
* The received byte is stored in *c. Returns 1 if a byte was read,
* 0 if no data was available, or EOF if trouble.
* --------------------------------