Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * variable.c
4 : * Routines for handling specialized SET variables.
5 : *
6 : *
7 : * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
8 : * Portions Copyright (c) 1994, Regents of the University of California
9 : *
10 : *
11 : * IDENTIFICATION
12 : * src/backend/commands/variable.c
13 : *
14 : *-------------------------------------------------------------------------
15 : */
16 :
17 : #include "postgres.h"
18 :
19 : #include <ctype.h>
20 :
21 : #include "access/htup_details.h"
22 : #include "access/parallel.h"
23 : #include "access/xact.h"
24 : #include "access/xlog.h"
25 : #include "access/xlogprefetcher.h"
26 : #include "catalog/pg_authid.h"
27 : #include "common/string.h"
28 : #include "mb/pg_wchar.h"
29 : #include "miscadmin.h"
30 : #include "postmaster/postmaster.h"
31 : #include "postmaster/syslogger.h"
32 : #include "storage/bufmgr.h"
33 : #include "utils/acl.h"
34 : #include "utils/backend_status.h"
35 : #include "utils/builtins.h"
36 : #include "utils/datetime.h"
37 : #include "utils/guc_hooks.h"
38 : #include "utils/snapmgr.h"
39 : #include "utils/syscache.h"
40 : #include "utils/timestamp.h"
41 : #include "utils/tzparser.h"
42 : #include "utils/varlena.h"
43 :
44 : /*
45 : * DATESTYLE
46 : */
47 :
48 : /*
49 : * check_datestyle: GUC check_hook for datestyle
50 : */
51 : bool
52 24978 : check_datestyle(char **newval, void **extra, GucSource source)
53 : {
54 24978 : int newDateStyle = DateStyle;
55 24978 : int newDateOrder = DateOrder;
56 24978 : bool have_style = false;
57 24978 : bool have_order = false;
58 24978 : bool ok = true;
59 : char *rawstring;
60 : int *myextra;
61 : char *result;
62 : List *elemlist;
63 : ListCell *l;
64 :
65 : /* Need a modifiable copy of string */
66 24978 : rawstring = pstrdup(*newval);
67 :
68 : /* Parse string into list of identifiers */
69 24978 : if (!SplitIdentifierString(rawstring, ',', &elemlist))
70 : {
71 : /* syntax error in list */
72 0 : GUC_check_errdetail("List syntax is invalid.");
73 0 : pfree(rawstring);
74 0 : list_free(elemlist);
75 0 : return false;
76 : }
77 :
78 66924 : foreach(l, elemlist)
79 : {
80 41946 : char *tok = (char *) lfirst(l);
81 :
82 : /* Ugh. Somebody ought to write a table driven version -- mjl */
83 :
84 41946 : if (pg_strcasecmp(tok, "ISO") == 0)
85 : {
86 17364 : if (have_style && newDateStyle != USE_ISO_DATES)
87 0 : ok = false; /* conflicting styles */
88 17364 : newDateStyle = USE_ISO_DATES;
89 17364 : have_style = true;
90 : }
91 24582 : else if (pg_strcasecmp(tok, "SQL") == 0)
92 : {
93 30 : if (have_style && newDateStyle != USE_SQL_DATES)
94 0 : ok = false; /* conflicting styles */
95 30 : newDateStyle = USE_SQL_DATES;
96 30 : have_style = true;
97 : }
98 24552 : else if (pg_strncasecmp(tok, "POSTGRES", 8) == 0)
99 : {
100 7492 : if (have_style && newDateStyle != USE_POSTGRES_DATES)
101 0 : ok = false; /* conflicting styles */
102 7492 : newDateStyle = USE_POSTGRES_DATES;
103 7492 : have_style = true;
104 : }
105 17060 : else if (pg_strcasecmp(tok, "GERMAN") == 0)
106 : {
107 42 : if (have_style && newDateStyle != USE_GERMAN_DATES)
108 0 : ok = false; /* conflicting styles */
109 42 : newDateStyle = USE_GERMAN_DATES;
110 42 : have_style = true;
111 : /* GERMAN also sets DMY, unless explicitly overridden */
112 42 : if (!have_order)
113 42 : newDateOrder = DATEORDER_DMY;
114 : }
115 17018 : else if (pg_strcasecmp(tok, "YMD") == 0)
116 : {
117 36 : if (have_order && newDateOrder != DATEORDER_YMD)
118 0 : ok = false; /* conflicting orders */
119 36 : newDateOrder = DATEORDER_YMD;
120 36 : have_order = true;
121 : }
122 33916 : else if (pg_strcasecmp(tok, "DMY") == 0 ||
123 16934 : pg_strncasecmp(tok, "EURO", 4) == 0)
124 : {
125 66 : if (have_order && newDateOrder != DATEORDER_DMY)
126 0 : ok = false; /* conflicting orders */
127 66 : newDateOrder = DATEORDER_DMY;
128 66 : have_order = true;
129 : }
130 16934 : else if (pg_strcasecmp(tok, "MDY") == 0 ||
131 18 : pg_strcasecmp(tok, "US") == 0 ||
132 0 : pg_strncasecmp(tok, "NONEURO", 7) == 0)
133 : {
134 16916 : if (have_order && newDateOrder != DATEORDER_MDY)
135 0 : ok = false; /* conflicting orders */
136 16916 : newDateOrder = DATEORDER_MDY;
137 16916 : have_order = true;
138 : }
139 0 : else if (pg_strcasecmp(tok, "DEFAULT") == 0)
140 : {
141 : /*
142 : * Easiest way to get the current DEFAULT state is to fetch the
143 : * DEFAULT string from guc.c and recursively parse it.
144 : *
145 : * We can't simply "return check_datestyle(...)" because we need
146 : * to handle constructs like "DEFAULT, ISO".
147 : */
148 : char *subval;
149 0 : void *subextra = NULL;
150 :
151 0 : subval = guc_strdup(LOG, GetConfigOptionResetString("datestyle"));
152 0 : if (!subval)
153 : {
154 0 : ok = false;
155 0 : break;
156 : }
157 0 : if (!check_datestyle(&subval, &subextra, source))
158 : {
159 0 : guc_free(subval);
160 0 : ok = false;
161 0 : break;
162 : }
163 0 : myextra = (int *) subextra;
164 0 : if (!have_style)
165 0 : newDateStyle = myextra[0];
166 0 : if (!have_order)
167 0 : newDateOrder = myextra[1];
168 0 : guc_free(subval);
169 0 : guc_free(subextra);
170 : }
171 : else
172 : {
173 0 : GUC_check_errdetail("Unrecognized key word: \"%s\".", tok);
174 0 : pfree(rawstring);
175 0 : list_free(elemlist);
176 0 : return false;
177 : }
178 : }
179 :
180 24978 : pfree(rawstring);
181 24978 : list_free(elemlist);
182 :
183 24978 : if (!ok)
184 : {
185 0 : GUC_check_errdetail("Conflicting \"datestyle\" specifications.");
186 0 : return false;
187 : }
188 :
189 : /*
190 : * Prepare the canonical string to return. GUC wants it guc_malloc'd.
191 : */
192 24978 : result = (char *) guc_malloc(LOG, 32);
193 24978 : if (!result)
194 0 : return false;
195 :
196 24978 : switch (newDateStyle)
197 : {
198 17388 : case USE_ISO_DATES:
199 17388 : strcpy(result, "ISO");
200 17388 : break;
201 30 : case USE_SQL_DATES:
202 30 : strcpy(result, "SQL");
203 30 : break;
204 42 : case USE_GERMAN_DATES:
205 42 : strcpy(result, "German");
206 42 : break;
207 7518 : default:
208 7518 : strcpy(result, "Postgres");
209 7518 : break;
210 : }
211 24978 : switch (newDateOrder)
212 : {
213 48 : case DATEORDER_YMD:
214 48 : strcat(result, ", YMD");
215 48 : break;
216 88 : case DATEORDER_DMY:
217 88 : strcat(result, ", DMY");
218 88 : break;
219 24842 : default:
220 24842 : strcat(result, ", MDY");
221 24842 : break;
222 : }
223 :
224 24978 : guc_free(*newval);
225 24978 : *newval = result;
226 :
227 : /*
228 : * Set up the "extra" struct actually used by assign_datestyle.
229 : */
230 24978 : myextra = (int *) guc_malloc(LOG, 2 * sizeof(int));
231 24978 : if (!myextra)
232 0 : return false;
233 24978 : myextra[0] = newDateStyle;
234 24978 : myextra[1] = newDateOrder;
235 24978 : *extra = (void *) myextra;
236 :
237 24978 : return true;
238 : }
239 :
240 : /*
241 : * assign_datestyle: GUC assign_hook for datestyle
242 : */
243 : void
244 31676 : assign_datestyle(const char *newval, void *extra)
245 : {
246 31676 : int *myextra = (int *) extra;
247 :
248 31676 : DateStyle = myextra[0];
249 31676 : DateOrder = myextra[1];
250 31676 : }
251 :
252 :
253 : /*
254 : * TIMEZONE
255 : */
256 :
257 : /*
258 : * check_timezone: GUC check_hook for timezone
259 : */
260 : bool
261 16350 : check_timezone(char **newval, void **extra, GucSource source)
262 : {
263 : pg_tz *new_tz;
264 : long gmtoffset;
265 : char *endptr;
266 : double hours;
267 :
268 16350 : if (pg_strncasecmp(*newval, "interval", 8) == 0)
269 : {
270 : /*
271 : * Support INTERVAL 'foo'. This is for SQL spec compliance, not
272 : * because it has any actual real-world usefulness.
273 : */
274 0 : const char *valueptr = *newval;
275 : char *val;
276 : Interval *interval;
277 :
278 0 : valueptr += 8;
279 0 : while (isspace((unsigned char) *valueptr))
280 0 : valueptr++;
281 0 : if (*valueptr++ != '\'')
282 0 : return false;
283 0 : val = pstrdup(valueptr);
284 : /* Check and remove trailing quote */
285 0 : endptr = strchr(val, '\'');
286 0 : if (!endptr || endptr[1] != '\0')
287 : {
288 0 : pfree(val);
289 0 : return false;
290 : }
291 0 : *endptr = '\0';
292 :
293 : /*
294 : * Try to parse it. XXX an invalid interval format will result in
295 : * ereport(ERROR), which is not desirable for GUC. We did what we
296 : * could to guard against this in flatten_set_variable_args, but a
297 : * string coming in from postgresql.conf might contain anything.
298 : */
299 0 : interval = DatumGetIntervalP(DirectFunctionCall3(interval_in,
300 : CStringGetDatum(val),
301 : ObjectIdGetDatum(InvalidOid),
302 : Int32GetDatum(-1)));
303 :
304 0 : pfree(val);
305 0 : if (interval->month != 0)
306 : {
307 0 : GUC_check_errdetail("Cannot specify months in time zone interval.");
308 0 : pfree(interval);
309 0 : return false;
310 : }
311 0 : if (interval->day != 0)
312 : {
313 0 : GUC_check_errdetail("Cannot specify days in time zone interval.");
314 0 : pfree(interval);
315 0 : return false;
316 : }
317 :
318 : /* Here we change from SQL to Unix sign convention */
319 0 : gmtoffset = -(interval->time / USECS_PER_SEC);
320 0 : new_tz = pg_tzset_offset(gmtoffset);
321 :
322 0 : pfree(interval);
323 : }
324 : else
325 : {
326 : /*
327 : * Try it as a numeric number of hours (possibly fractional).
328 : */
329 16350 : hours = strtod(*newval, &endptr);
330 16350 : if (endptr != *newval && *endptr == '\0')
331 : {
332 : /* Here we change from SQL to Unix sign convention */
333 66 : gmtoffset = -hours * SECS_PER_HOUR;
334 66 : new_tz = pg_tzset_offset(gmtoffset);
335 : }
336 : else
337 : {
338 : /*
339 : * Otherwise assume it is a timezone name, and try to load it.
340 : */
341 16284 : new_tz = pg_tzset(*newval);
342 :
343 16284 : if (!new_tz)
344 : {
345 : /* Doesn't seem to be any great value in errdetail here */
346 0 : return false;
347 : }
348 :
349 16284 : if (!pg_tz_acceptable(new_tz))
350 : {
351 0 : GUC_check_errmsg("time zone \"%s\" appears to use leap seconds",
352 : *newval);
353 0 : GUC_check_errdetail("PostgreSQL does not support leap seconds.");
354 0 : return false;
355 : }
356 : }
357 : }
358 :
359 : /* Test for failure in pg_tzset_offset, which we assume is out-of-range */
360 16350 : if (!new_tz)
361 : {
362 0 : GUC_check_errdetail("UTC timezone offset is out of range.");
363 0 : return false;
364 : }
365 :
366 : /*
367 : * Pass back data for assign_timezone to use
368 : */
369 16350 : *extra = guc_malloc(LOG, sizeof(pg_tz *));
370 16350 : if (!*extra)
371 0 : return false;
372 16350 : *((pg_tz **) *extra) = new_tz;
373 :
374 16350 : return true;
375 : }
376 :
377 : /*
378 : * assign_timezone: GUC assign_hook for timezone
379 : */
380 : void
381 16438 : assign_timezone(const char *newval, void *extra)
382 : {
383 16438 : session_timezone = *((pg_tz **) extra);
384 16438 : }
385 :
386 : /*
387 : * show_timezone: GUC show_hook for timezone
388 : */
389 : const char *
390 43906 : show_timezone(void)
391 : {
392 : const char *tzn;
393 :
394 : /* Always show the zone's canonical name */
395 43906 : tzn = pg_get_timezone_name(session_timezone);
396 :
397 43906 : if (tzn != NULL)
398 43906 : return tzn;
399 :
400 0 : return "unknown";
401 : }
402 :
403 :
404 : /*
405 : * LOG_TIMEZONE
406 : *
407 : * For log_timezone, we don't support the interval-based methods of setting a
408 : * zone, which are only there for SQL spec compliance not because they're
409 : * actually useful.
410 : */
411 :
412 : /*
413 : * check_log_timezone: GUC check_hook for log_timezone
414 : */
415 : bool
416 11986 : check_log_timezone(char **newval, void **extra, GucSource source)
417 : {
418 : pg_tz *new_tz;
419 :
420 : /*
421 : * Assume it is a timezone name, and try to load it.
422 : */
423 11986 : new_tz = pg_tzset(*newval);
424 :
425 11986 : if (!new_tz)
426 : {
427 : /* Doesn't seem to be any great value in errdetail here */
428 0 : return false;
429 : }
430 :
431 11986 : if (!pg_tz_acceptable(new_tz))
432 : {
433 0 : GUC_check_errmsg("time zone \"%s\" appears to use leap seconds",
434 : *newval);
435 0 : GUC_check_errdetail("PostgreSQL does not support leap seconds.");
436 0 : return false;
437 : }
438 :
439 : /*
440 : * Pass back data for assign_log_timezone to use
441 : */
442 11986 : *extra = guc_malloc(LOG, sizeof(pg_tz *));
443 11986 : if (!*extra)
444 0 : return false;
445 11986 : *((pg_tz **) *extra) = new_tz;
446 :
447 11986 : return true;
448 : }
449 :
450 : /*
451 : * assign_log_timezone: GUC assign_hook for log_timezone
452 : */
453 : void
454 11980 : assign_log_timezone(const char *newval, void *extra)
455 : {
456 11980 : log_timezone = *((pg_tz **) extra);
457 11980 : }
458 :
459 : /*
460 : * show_log_timezone: GUC show_hook for log_timezone
461 : */
462 : const char *
463 2242 : show_log_timezone(void)
464 : {
465 : const char *tzn;
466 :
467 : /* Always show the zone's canonical name */
468 2242 : tzn = pg_get_timezone_name(log_timezone);
469 :
470 2242 : if (tzn != NULL)
471 2242 : return tzn;
472 :
473 0 : return "unknown";
474 : }
475 :
476 :
477 : /*
478 : * TIMEZONE_ABBREVIATIONS
479 : */
480 :
481 : /*
482 : * GUC check_hook for assign_timezone_abbreviations
483 : */
484 : bool
485 19678 : check_timezone_abbreviations(char **newval, void **extra, GucSource source)
486 : {
487 : /*
488 : * The boot_val for timezone_abbreviations is NULL. When we see that we
489 : * just do nothing. If the value isn't overridden from the config file
490 : * then pg_timezone_abbrev_initialize() will eventually replace it with
491 : * "Default". This hack has two purposes: to avoid wasting cycles loading
492 : * values that might soon be overridden from the config file, and to avoid
493 : * trying to read the timezone abbrev files during InitializeGUCOptions().
494 : * The latter doesn't work in an EXEC_BACKEND subprocess because
495 : * my_exec_path hasn't been set yet and so we can't locate PGSHAREDIR.
496 : */
497 19678 : if (*newval == NULL)
498 : {
499 : Assert(source == PGC_S_DEFAULT);
500 6304 : return true;
501 : }
502 :
503 : /* OK, load the file and produce a guc_malloc'd TimeZoneAbbrevTable */
504 13374 : *extra = load_tzoffsets(*newval);
505 :
506 : /* tzparser.c returns NULL on failure, reporting via GUC_check_errmsg */
507 13374 : if (!*extra)
508 0 : return false;
509 :
510 13374 : return true;
511 : }
512 :
513 : /*
514 : * GUC assign_hook for assign_timezone_abbreviations
515 : */
516 : void
517 19502 : assign_timezone_abbreviations(const char *newval, void *extra)
518 : {
519 : /* Do nothing for the boot_val default of NULL */
520 19502 : if (!extra)
521 6304 : return;
522 :
523 13198 : InstallTimeZoneAbbrevs((TimeZoneAbbrevTable *) extra);
524 : }
525 :
526 :
527 : /*
528 : * SET TRANSACTION READ ONLY and SET TRANSACTION READ WRITE
529 : *
530 : * We allow idempotent changes (r/w -> r/w and r/o -> r/o) at any time, and
531 : * we also always allow changes from read-write to read-only. However,
532 : * read-only may be changed to read-write only when in a top-level transaction
533 : * that has not yet taken an initial snapshot. Can't do it in a hot standby,
534 : * either.
535 : *
536 : * If we are not in a transaction at all, just allow the change; it means
537 : * nothing since XactReadOnly will be reset by the next StartTransaction().
538 : * The IsTransactionState() test protects us against trying to check
539 : * RecoveryInProgress() in contexts where shared memory is not accessible.
540 : * (Similarly, if we're restoring state in a parallel worker, just allow
541 : * the change.)
542 : */
543 : bool
544 13866 : check_transaction_read_only(bool *newval, void **extra, GucSource source)
545 : {
546 13866 : if (*newval == false && XactReadOnly && IsTransactionState() && !InitializingParallelWorker)
547 : {
548 : /* Can't go to r/w mode inside a r/o transaction */
549 58 : if (IsSubTransaction())
550 : {
551 12 : GUC_check_errcode(ERRCODE_ACTIVE_SQL_TRANSACTION);
552 12 : GUC_check_errmsg("cannot set transaction read-write mode inside a read-only transaction");
553 12 : return false;
554 : }
555 : /* Top level transaction can't change to r/w after first snapshot. */
556 46 : if (FirstSnapshotSet)
557 : {
558 6 : GUC_check_errcode(ERRCODE_ACTIVE_SQL_TRANSACTION);
559 6 : GUC_check_errmsg("transaction read-write mode must be set before any query");
560 6 : return false;
561 : }
562 : /* Can't go to r/w mode while recovery is still active */
563 40 : if (RecoveryInProgress())
564 : {
565 0 : GUC_check_errcode(ERRCODE_FEATURE_NOT_SUPPORTED);
566 0 : GUC_check_errmsg("cannot set transaction read-write mode during recovery");
567 0 : return false;
568 : }
569 : }
570 :
571 13848 : return true;
572 : }
573 :
574 : /*
575 : * SET TRANSACTION ISOLATION LEVEL
576 : *
577 : * We allow idempotent changes at any time, but otherwise this can only be
578 : * changed in a toplevel transaction that has not yet taken a snapshot.
579 : *
580 : * As in check_transaction_read_only, allow it if not inside a transaction.
581 : */
582 : bool
583 18980 : check_transaction_isolation(int *newval, void **extra, GucSource source)
584 : {
585 18980 : int newXactIsoLevel = *newval;
586 :
587 18980 : if (newXactIsoLevel != XactIsoLevel && IsTransactionState())
588 : {
589 5562 : if (FirstSnapshotSet)
590 : {
591 2 : GUC_check_errcode(ERRCODE_ACTIVE_SQL_TRANSACTION);
592 2 : GUC_check_errmsg("SET TRANSACTION ISOLATION LEVEL must be called before any query");
593 2 : return false;
594 : }
595 : /* We ignore a subtransaction setting it to the existing value. */
596 5560 : if (IsSubTransaction())
597 : {
598 0 : GUC_check_errcode(ERRCODE_ACTIVE_SQL_TRANSACTION);
599 0 : GUC_check_errmsg("SET TRANSACTION ISOLATION LEVEL must not be called in a subtransaction");
600 0 : return false;
601 : }
602 : /* Can't go to serializable mode while recovery is still active */
603 5560 : if (newXactIsoLevel == XACT_SERIALIZABLE && RecoveryInProgress())
604 : {
605 0 : GUC_check_errcode(ERRCODE_FEATURE_NOT_SUPPORTED);
606 0 : GUC_check_errmsg("cannot use serializable mode in a hot standby");
607 0 : GUC_check_errhint("You can use REPEATABLE READ instead.");
608 0 : return false;
609 : }
610 : }
611 :
612 18978 : return true;
613 : }
614 :
615 : /*
616 : * SET TRANSACTION [NOT] DEFERRABLE
617 : */
618 :
619 : bool
620 12656 : check_transaction_deferrable(bool *newval, void **extra, GucSource source)
621 : {
622 12656 : if (IsSubTransaction())
623 : {
624 0 : GUC_check_errcode(ERRCODE_ACTIVE_SQL_TRANSACTION);
625 0 : GUC_check_errmsg("SET TRANSACTION [NOT] DEFERRABLE cannot be called within a subtransaction");
626 0 : return false;
627 : }
628 12656 : if (FirstSnapshotSet)
629 : {
630 0 : GUC_check_errcode(ERRCODE_ACTIVE_SQL_TRANSACTION);
631 0 : GUC_check_errmsg("SET TRANSACTION [NOT] DEFERRABLE must be called before any query");
632 0 : return false;
633 : }
634 :
635 12656 : return true;
636 : }
637 :
638 : /*
639 : * Random number seed
640 : *
641 : * We can't roll back the random sequence on error, and we don't want
642 : * config file reloads to affect it, so we only want interactive SET SEED
643 : * commands to set it. We use the "extra" storage to ensure that rollbacks
644 : * don't try to do the operation again.
645 : */
646 :
647 : bool
648 3698 : check_random_seed(double *newval, void **extra, GucSource source)
649 : {
650 3698 : *extra = guc_malloc(LOG, sizeof(int));
651 3698 : if (!*extra)
652 0 : return false;
653 : /* Arm the assign only if source of value is an interactive SET */
654 3698 : *((int *) *extra) = (source >= PGC_S_INTERACTIVE);
655 :
656 3698 : return true;
657 : }
658 :
659 : void
660 3698 : assign_random_seed(double newval, void *extra)
661 : {
662 : /* We'll do this at most once for any setting of the GUC variable */
663 3698 : if (*((int *) extra))
664 0 : DirectFunctionCall1(setseed, Float8GetDatum(newval));
665 3698 : *((int *) extra) = 0;
666 3698 : }
667 :
668 : const char *
669 0 : show_random_seed(void)
670 : {
671 0 : return "unavailable";
672 : }
673 :
674 :
675 : /*
676 : * SET CLIENT_ENCODING
677 : */
678 :
679 : bool
680 34748 : check_client_encoding(char **newval, void **extra, GucSource source)
681 : {
682 : int encoding;
683 : const char *canonical_name;
684 :
685 : /* Look up the encoding by name */
686 34748 : encoding = pg_valid_client_encoding(*newval);
687 34748 : if (encoding < 0)
688 0 : return false;
689 :
690 : /* Get the canonical name (no aliases, uniform case) */
691 34748 : canonical_name = pg_encoding_to_char(encoding);
692 :
693 : /*
694 : * If we are not within a transaction then PrepareClientEncoding will not
695 : * be able to look up the necessary conversion procs. If we are still
696 : * starting up, it will return "OK" anyway, and InitializeClientEncoding
697 : * will fix things once initialization is far enough along. After
698 : * startup, we'll fail. This would only happen if someone tries to change
699 : * client_encoding in postgresql.conf and then SIGHUP existing sessions.
700 : * It seems like a bad idea for client_encoding to change that way anyhow,
701 : * so we don't go out of our way to support it.
702 : *
703 : * Note: in the postmaster, or any other process that never calls
704 : * InitializeClientEncoding, PrepareClientEncoding will always succeed,
705 : * and so will SetClientEncoding; but they won't do anything, which is OK.
706 : */
707 34748 : if (PrepareClientEncoding(encoding) < 0)
708 : {
709 0 : if (IsTransactionState())
710 : {
711 : /* Must be a genuine no-such-conversion problem */
712 0 : GUC_check_errcode(ERRCODE_FEATURE_NOT_SUPPORTED);
713 0 : GUC_check_errdetail("Conversion between %s and %s is not supported.",
714 : canonical_name,
715 : GetDatabaseEncodingName());
716 : }
717 : else
718 : {
719 : /* Provide a useful complaint */
720 0 : GUC_check_errdetail("Cannot change \"client_encoding\" now.");
721 : }
722 0 : return false;
723 : }
724 :
725 : /*
726 : * Replace the user-supplied string with the encoding's canonical name.
727 : * This gets rid of aliases and case-folding variations.
728 : *
729 : * XXX Although canonicalizing seems like a good idea in the abstract, it
730 : * breaks pre-9.1 JDBC drivers, which expect that if they send "UNICODE"
731 : * as the client_encoding setting then it will read back the same way. As
732 : * a workaround, don't replace the string if it's "UNICODE". Remove that
733 : * hack when pre-9.1 JDBC drivers are no longer in use.
734 : */
735 34748 : if (strcmp(*newval, canonical_name) != 0 &&
736 24 : strcmp(*newval, "UNICODE") != 0)
737 : {
738 24 : guc_free(*newval);
739 24 : *newval = guc_strdup(LOG, canonical_name);
740 24 : if (!*newval)
741 0 : return false;
742 : }
743 :
744 : /*
745 : * Save the encoding's ID in *extra, for use by assign_client_encoding.
746 : */
747 34748 : *extra = guc_malloc(LOG, sizeof(int));
748 34748 : if (!*extra)
749 0 : return false;
750 34748 : *((int *) *extra) = encoding;
751 :
752 34748 : return true;
753 : }
754 :
755 : void
756 34562 : assign_client_encoding(const char *newval, void *extra)
757 : {
758 34562 : int encoding = *((int *) extra);
759 :
760 : /*
761 : * Parallel workers send data to the leader, not the client. They always
762 : * send data using the database encoding.
763 : */
764 34562 : if (IsParallelWorker())
765 : {
766 : /*
767 : * During parallel worker startup, we want to accept the leader's
768 : * client_encoding setting so that anyone who looks at the value in
769 : * the worker sees the same value that they would see in the leader.
770 : */
771 7818 : if (InitializingParallelWorker)
772 7818 : return;
773 :
774 : /*
775 : * A change other than during startup, for example due to a SET clause
776 : * attached to a function definition, should be rejected, as there is
777 : * nothing we can do inside the worker to make it take effect.
778 : */
779 0 : ereport(ERROR,
780 : (errcode(ERRCODE_INVALID_TRANSACTION_STATE),
781 : errmsg("cannot change client_encoding during a parallel operation")));
782 : }
783 :
784 : /* We do not expect an error if PrepareClientEncoding succeeded */
785 26744 : if (SetClientEncoding(encoding) < 0)
786 0 : elog(LOG, "SetClientEncoding(%d) failed", encoding);
787 : }
788 :
789 :
790 : /*
791 : * SET SESSION AUTHORIZATION
792 : */
793 :
794 : typedef struct
795 : {
796 : /* This is the "extra" state for both SESSION AUTHORIZATION and ROLE */
797 : Oid roleid;
798 : bool is_superuser;
799 : } role_auth_extra;
800 :
801 : bool
802 35196 : check_session_authorization(char **newval, void **extra, GucSource source)
803 : {
804 : HeapTuple roleTup;
805 : Form_pg_authid roleform;
806 : Oid roleid;
807 : bool is_superuser;
808 : role_auth_extra *myextra;
809 :
810 : /* Do nothing for the boot_val default of NULL */
811 35196 : if (*newval == NULL)
812 6304 : return true;
813 :
814 28892 : if (!IsTransactionState())
815 : {
816 : /*
817 : * Can't do catalog lookups, so fail. The result of this is that
818 : * session_authorization cannot be set in postgresql.conf, which seems
819 : * like a good thing anyway, so we don't work hard to avoid it.
820 : */
821 0 : return false;
822 : }
823 :
824 : /* Look up the username */
825 28892 : roleTup = SearchSysCache1(AUTHNAME, PointerGetDatum(*newval));
826 28892 : if (!HeapTupleIsValid(roleTup))
827 : {
828 : /*
829 : * When source == PGC_S_TEST, we don't throw a hard error for a
830 : * nonexistent user name, only a NOTICE. See comments in guc.h.
831 : */
832 0 : if (source == PGC_S_TEST)
833 : {
834 0 : ereport(NOTICE,
835 : (errcode(ERRCODE_UNDEFINED_OBJECT),
836 : errmsg("role \"%s\" does not exist", *newval)));
837 0 : return true;
838 : }
839 0 : GUC_check_errmsg("role \"%s\" does not exist", *newval);
840 0 : return false;
841 : }
842 :
843 28892 : roleform = (Form_pg_authid) GETSTRUCT(roleTup);
844 28892 : roleid = roleform->oid;
845 28892 : is_superuser = roleform->rolsuper;
846 :
847 28892 : ReleaseSysCache(roleTup);
848 :
849 : /* Set up "extra" struct for assign_session_authorization to use */
850 28892 : myextra = (role_auth_extra *) guc_malloc(LOG, sizeof(role_auth_extra));
851 28892 : if (!myextra)
852 0 : return false;
853 28892 : myextra->roleid = roleid;
854 28892 : myextra->is_superuser = is_superuser;
855 28892 : *extra = (void *) myextra;
856 :
857 28892 : return true;
858 : }
859 :
860 : void
861 36040 : assign_session_authorization(const char *newval, void *extra)
862 : {
863 36040 : role_auth_extra *myextra = (role_auth_extra *) extra;
864 :
865 : /* Do nothing for the boot_val default of NULL */
866 36040 : if (!myextra)
867 6304 : return;
868 :
869 29736 : SetSessionAuthorization(myextra->roleid, myextra->is_superuser);
870 : }
871 :
872 :
873 : /*
874 : * SET ROLE
875 : *
876 : * The SQL spec requires "SET ROLE NONE" to unset the role, so we hardwire
877 : * a translation of "none" to InvalidOid. Otherwise this is much like
878 : * SET SESSION AUTHORIZATION.
879 : */
880 : extern char *role_string; /* in guc_tables.c */
881 :
882 : bool
883 4524 : check_role(char **newval, void **extra, GucSource source)
884 : {
885 : HeapTuple roleTup;
886 : Oid roleid;
887 : bool is_superuser;
888 : role_auth_extra *myextra;
889 : Form_pg_authid roleform;
890 :
891 4524 : if (strcmp(*newval, "none") == 0)
892 : {
893 : /* hardwired translation */
894 3698 : roleid = InvalidOid;
895 3698 : is_superuser = false;
896 : }
897 : else
898 : {
899 826 : if (!IsTransactionState())
900 : {
901 : /*
902 : * Can't do catalog lookups, so fail. The result of this is that
903 : * role cannot be set in postgresql.conf, which seems like a good
904 : * thing anyway, so we don't work hard to avoid it.
905 : */
906 0 : return false;
907 : }
908 :
909 : /*
910 : * When source == PGC_S_TEST, we don't throw a hard error for a
911 : * nonexistent user name or insufficient privileges, only a NOTICE.
912 : * See comments in guc.h.
913 : */
914 :
915 : /* Look up the username */
916 826 : roleTup = SearchSysCache1(AUTHNAME, PointerGetDatum(*newval));
917 826 : if (!HeapTupleIsValid(roleTup))
918 : {
919 0 : if (source == PGC_S_TEST)
920 : {
921 0 : ereport(NOTICE,
922 : (errcode(ERRCODE_UNDEFINED_OBJECT),
923 : errmsg("role \"%s\" does not exist", *newval)));
924 0 : return true;
925 : }
926 0 : GUC_check_errmsg("role \"%s\" does not exist", *newval);
927 0 : return false;
928 : }
929 :
930 826 : roleform = (Form_pg_authid) GETSTRUCT(roleTup);
931 826 : roleid = roleform->oid;
932 826 : is_superuser = roleform->rolsuper;
933 :
934 826 : ReleaseSysCache(roleTup);
935 :
936 : /*
937 : * Verify that session user is allowed to become this role, but skip
938 : * this in parallel mode, where we must blindly recreate the parallel
939 : * leader's state.
940 : */
941 826 : if (!InitializingParallelWorker &&
942 826 : !member_can_set_role(GetSessionUserId(), roleid))
943 : {
944 12 : if (source == PGC_S_TEST)
945 : {
946 0 : ereport(NOTICE,
947 : (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
948 : errmsg("permission will be denied to set role \"%s\"",
949 : *newval)));
950 0 : return true;
951 : }
952 12 : GUC_check_errcode(ERRCODE_INSUFFICIENT_PRIVILEGE);
953 12 : GUC_check_errmsg("permission denied to set role \"%s\"",
954 : *newval);
955 12 : return false;
956 : }
957 : }
958 :
959 : /* Set up "extra" struct for assign_role to use */
960 4512 : myextra = (role_auth_extra *) guc_malloc(LOG, sizeof(role_auth_extra));
961 4512 : if (!myextra)
962 0 : return false;
963 4512 : myextra->roleid = roleid;
964 4512 : myextra->is_superuser = is_superuser;
965 4512 : *extra = (void *) myextra;
966 :
967 4512 : return true;
968 : }
969 :
970 : void
971 5104 : assign_role(const char *newval, void *extra)
972 : {
973 5104 : role_auth_extra *myextra = (role_auth_extra *) extra;
974 :
975 5104 : SetCurrentRoleId(myextra->roleid, myextra->is_superuser);
976 5104 : }
977 :
978 : const char *
979 0 : show_role(void)
980 : {
981 : /*
982 : * Check whether SET ROLE is active; if not return "none". This is a
983 : * kluge to deal with the fact that SET SESSION AUTHORIZATION logically
984 : * resets SET ROLE to NONE, but we cannot set the GUC role variable from
985 : * assign_session_authorization (because we haven't got enough info to
986 : * call set_config_option).
987 : */
988 0 : if (!OidIsValid(GetCurrentRoleId()))
989 0 : return "none";
990 :
991 : /* Otherwise we can just use the GUC string */
992 0 : return role_string ? role_string : "none";
993 : }
994 :
995 :
996 : /*
997 : * PATH VARIABLES
998 : *
999 : * check_canonical_path is used for log_directory and some other GUCs where
1000 : * all we want to do is canonicalize the represented path name.
1001 : */
1002 :
1003 : bool
1004 7396 : check_canonical_path(char **newval, void **extra, GucSource source)
1005 : {
1006 : /*
1007 : * Since canonicalize_path never enlarges the string, we can just modify
1008 : * newval in-place. But watch out for NULL, which is the default value
1009 : * for external_pid_file.
1010 : */
1011 7396 : if (*newval)
1012 3698 : canonicalize_path(*newval);
1013 7396 : return true;
1014 : }
1015 :
1016 :
1017 : /*
1018 : * MISCELLANEOUS
1019 : */
1020 :
1021 : /*
1022 : * GUC check_hook for application_name
1023 : */
1024 : bool
1025 27828 : check_application_name(char **newval, void **extra, GucSource source)
1026 : {
1027 : char *clean;
1028 : char *ret;
1029 :
1030 : /* Only allow clean ASCII chars in the application name */
1031 27828 : clean = pg_clean_ascii(*newval, MCXT_ALLOC_NO_OOM);
1032 27828 : if (!clean)
1033 0 : return false;
1034 :
1035 27828 : ret = guc_strdup(WARNING, clean);
1036 27828 : if (!ret)
1037 : {
1038 0 : pfree(clean);
1039 0 : return false;
1040 : }
1041 :
1042 27828 : pfree(clean);
1043 27828 : *newval = ret;
1044 27828 : return true;
1045 : }
1046 :
1047 : /*
1048 : * GUC assign_hook for application_name
1049 : */
1050 : void
1051 27800 : assign_application_name(const char *newval, void *extra)
1052 : {
1053 : /* Update the pg_stat_activity view */
1054 27800 : pgstat_report_appname(newval);
1055 27800 : }
1056 :
1057 : /*
1058 : * GUC check_hook for cluster_name
1059 : */
1060 : bool
1061 4700 : check_cluster_name(char **newval, void **extra, GucSource source)
1062 : {
1063 : char *clean;
1064 : char *ret;
1065 :
1066 : /* Only allow clean ASCII chars in the cluster name */
1067 4700 : clean = pg_clean_ascii(*newval, MCXT_ALLOC_NO_OOM);
1068 4700 : if (!clean)
1069 0 : return false;
1070 :
1071 4700 : ret = guc_strdup(WARNING, clean);
1072 4700 : if (!ret)
1073 : {
1074 0 : pfree(clean);
1075 0 : return false;
1076 : }
1077 :
1078 4700 : pfree(clean);
1079 4700 : *newval = ret;
1080 4700 : return true;
1081 : }
1082 :
1083 : /*
1084 : * GUC assign_hook for maintenance_io_concurrency
1085 : */
1086 : void
1087 3698 : assign_maintenance_io_concurrency(int newval, void *extra)
1088 : {
1089 : #ifdef USE_PREFETCH
1090 : /*
1091 : * Reconfigure recovery prefetching, because a setting it depends on
1092 : * changed.
1093 : */
1094 3698 : maintenance_io_concurrency = newval;
1095 3698 : if (AmStartupProcess())
1096 0 : XLogPrefetchReconfigure();
1097 : #endif
1098 3698 : }
1099 :
1100 :
1101 : /*
1102 : * These show hooks just exist because we want to show the values in octal.
1103 : */
1104 :
1105 : /*
1106 : * GUC show_hook for data_directory_mode
1107 : */
1108 : const char *
1109 2812 : show_data_directory_mode(void)
1110 : {
1111 : static char buf[12];
1112 :
1113 2812 : snprintf(buf, sizeof(buf), "%04o", data_directory_mode);
1114 2812 : return buf;
1115 : }
1116 :
1117 : /*
1118 : * GUC show_hook for log_file_mode
1119 : */
1120 : const char *
1121 2242 : show_log_file_mode(void)
1122 : {
1123 : static char buf[12];
1124 :
1125 2242 : snprintf(buf, sizeof(buf), "%04o", Log_file_mode);
1126 2242 : return buf;
1127 : }
1128 :
1129 : /*
1130 : * GUC show_hook for unix_socket_permissions
1131 : */
1132 : const char *
1133 2242 : show_unix_socket_permissions(void)
1134 : {
1135 : static char buf[12];
1136 :
1137 2242 : snprintf(buf, sizeof(buf), "%04o", Unix_socket_permissions);
1138 2242 : return buf;
1139 : }
1140 :
1141 :
1142 : /*
1143 : * These check hooks do nothing more than reject non-default settings
1144 : * in builds that don't support them.
1145 : */
1146 :
1147 : bool
1148 3698 : check_bonjour(bool *newval, void **extra, GucSource source)
1149 : {
1150 : #ifndef USE_BONJOUR
1151 3698 : if (*newval)
1152 : {
1153 0 : GUC_check_errmsg("Bonjour is not supported by this build");
1154 0 : return false;
1155 : }
1156 : #endif
1157 3698 : return true;
1158 : }
1159 :
1160 : bool
1161 3710 : check_default_with_oids(bool *newval, void **extra, GucSource source)
1162 : {
1163 3710 : if (*newval)
1164 : {
1165 : /* check the GUC's definition for an explanation */
1166 6 : GUC_check_errcode(ERRCODE_FEATURE_NOT_SUPPORTED);
1167 6 : GUC_check_errmsg("tables declared WITH OIDS are not supported");
1168 :
1169 6 : return false;
1170 : }
1171 :
1172 3704 : return true;
1173 : }
1174 :
1175 : bool
1176 4292 : check_effective_io_concurrency(int *newval, void **extra, GucSource source)
1177 : {
1178 : #ifndef USE_PREFETCH
1179 : if (*newval != 0)
1180 : {
1181 : GUC_check_errdetail("effective_io_concurrency must be set to 0 on platforms that lack posix_fadvise().");
1182 : return false;
1183 : }
1184 : #endif /* USE_PREFETCH */
1185 4292 : return true;
1186 : }
1187 :
1188 : bool
1189 3698 : check_maintenance_io_concurrency(int *newval, void **extra, GucSource source)
1190 : {
1191 : #ifndef USE_PREFETCH
1192 : if (*newval != 0)
1193 : {
1194 : GUC_check_errdetail("maintenance_io_concurrency must be set to 0 on platforms that lack posix_fadvise().");
1195 : return false;
1196 : }
1197 : #endif /* USE_PREFETCH */
1198 3698 : return true;
1199 : }
1200 :
1201 : bool
1202 3750 : check_ssl(bool *newval, void **extra, GucSource source)
1203 : {
1204 : #ifndef USE_SSL
1205 : if (*newval)
1206 : {
1207 : GUC_check_errmsg("SSL is not supported by this build");
1208 : return false;
1209 : }
1210 : #endif
1211 3750 : return true;
1212 : }
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