Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * variable.c
4 : * Routines for handling specialized SET variables.
5 : *
6 : *
7 : * Portions Copyright (c) 1996-2024, 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/datetime.h"
36 : #include "utils/fmgrprotos.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 23736 : check_datestyle(char **newval, void **extra, GucSource source)
53 : {
54 23736 : int newDateStyle = DateStyle;
55 23736 : int newDateOrder = DateOrder;
56 23736 : bool have_style = false;
57 23736 : bool have_order = false;
58 23736 : 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 23736 : rawstring = pstrdup(*newval);
67 :
68 : /* Parse string into list of identifiers */
69 23736 : 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 61542 : foreach(l, elemlist)
79 : {
80 37806 : char *tok = (char *) lfirst(l);
81 :
82 : /* Ugh. Somebody ought to write a table driven version -- mjl */
83 :
84 37806 : if (pg_strcasecmp(tok, "ISO") == 0)
85 : {
86 16574 : if (have_style && newDateStyle != USE_ISO_DATES)
87 0 : ok = false; /* conflicting styles */
88 16574 : newDateStyle = USE_ISO_DATES;
89 16574 : have_style = true;
90 : }
91 21232 : 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 21202 : else if (pg_strncasecmp(tok, "POSTGRES", 8) == 0)
99 : {
100 7040 : if (have_style && newDateStyle != USE_POSTGRES_DATES)
101 0 : ok = false; /* conflicting styles */
102 7040 : newDateStyle = USE_POSTGRES_DATES;
103 7040 : have_style = true;
104 : }
105 14162 : 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 14120 : 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 28120 : else if (pg_strcasecmp(tok, "DMY") == 0 ||
123 14036 : 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 14036 : else if (pg_strcasecmp(tok, "MDY") == 0 ||
131 18 : pg_strcasecmp(tok, "US") == 0 ||
132 0 : pg_strncasecmp(tok, "NONEURO", 7) == 0)
133 : {
134 14018 : if (have_order && newDateOrder != DATEORDER_MDY)
135 0 : ok = false; /* conflicting orders */
136 14018 : newDateOrder = DATEORDER_MDY;
137 14018 : 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 23736 : pfree(rawstring);
181 23736 : list_free(elemlist);
182 :
183 23736 : 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 23736 : result = (char *) guc_malloc(LOG, 32);
193 23736 : if (!result)
194 0 : return false;
195 :
196 23736 : switch (newDateStyle)
197 : {
198 16598 : case USE_ISO_DATES:
199 16598 : strcpy(result, "ISO");
200 16598 : 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 7066 : default:
208 7066 : strcpy(result, "Postgres");
209 7066 : break;
210 : }
211 23736 : 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 23600 : default:
220 23600 : strcat(result, ", MDY");
221 23600 : break;
222 : }
223 :
224 23736 : guc_free(*newval);
225 23736 : *newval = result;
226 :
227 : /*
228 : * Set up the "extra" struct actually used by assign_datestyle.
229 : */
230 23736 : myextra = (int *) guc_malloc(LOG, 2 * sizeof(int));
231 23736 : if (!myextra)
232 0 : return false;
233 23736 : myextra[0] = newDateStyle;
234 23736 : myextra[1] = newDateOrder;
235 23736 : *extra = (void *) myextra;
236 :
237 23736 : return true;
238 : }
239 :
240 : /*
241 : * assign_datestyle: GUC assign_hook for datestyle
242 : */
243 : void
244 31852 : assign_datestyle(const char *newval, void *extra)
245 : {
246 31852 : int *myextra = (int *) extra;
247 :
248 31852 : DateStyle = myextra[0];
249 31852 : DateOrder = myextra[1];
250 31852 : }
251 :
252 :
253 : /*
254 : * TIMEZONE
255 : */
256 :
257 : /*
258 : * check_timezone: GUC check_hook for timezone
259 : */
260 : bool
261 14122 : 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 14122 : 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 14122 : hours = strtod(*newval, &endptr);
330 14122 : if (endptr != *newval && *endptr == '\0')
331 : {
332 : /* Here we change from SQL to Unix sign convention */
333 72 : gmtoffset = -hours * SECS_PER_HOUR;
334 72 : 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 14050 : new_tz = pg_tzset(*newval);
342 :
343 14050 : if (!new_tz)
344 : {
345 : /* Doesn't seem to be any great value in errdetail here */
346 0 : return false;
347 : }
348 :
349 14050 : 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 14122 : 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 14122 : *extra = guc_malloc(LOG, sizeof(pg_tz *));
370 14122 : if (!*extra)
371 0 : return false;
372 14122 : *((pg_tz **) *extra) = new_tz;
373 :
374 14122 : return true;
375 : }
376 :
377 : /*
378 : * assign_timezone: GUC assign_hook for timezone
379 : */
380 : void
381 14222 : assign_timezone(const char *newval, void *extra)
382 : {
383 14222 : session_timezone = *((pg_tz **) extra);
384 14222 : }
385 :
386 : /*
387 : * show_timezone: GUC show_hook for timezone
388 : */
389 : const char *
390 45948 : show_timezone(void)
391 : {
392 : const char *tzn;
393 :
394 : /* Always show the zone's canonical name */
395 45948 : tzn = pg_get_timezone_name(session_timezone);
396 :
397 45948 : if (tzn != NULL)
398 45948 : 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 9562 : 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 9562 : new_tz = pg_tzset(*newval);
424 :
425 9562 : if (!new_tz)
426 : {
427 : /* Doesn't seem to be any great value in errdetail here */
428 0 : return false;
429 : }
430 :
431 9562 : 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 9562 : *extra = guc_malloc(LOG, sizeof(pg_tz *));
443 9562 : if (!*extra)
444 0 : return false;
445 9562 : *((pg_tz **) *extra) = new_tz;
446 :
447 9562 : return true;
448 : }
449 :
450 : /*
451 : * assign_log_timezone: GUC assign_hook for log_timezone
452 : */
453 : void
454 9556 : assign_log_timezone(const char *newval, void *extra)
455 : {
456 9556 : log_timezone = *((pg_tz **) extra);
457 9556 : }
458 :
459 : /*
460 : * show_log_timezone: GUC show_hook for log_timezone
461 : */
462 : const char *
463 3856 : show_log_timezone(void)
464 : {
465 : const char *tzn;
466 :
467 : /* Always show the zone's canonical name */
468 3856 : tzn = pg_get_timezone_name(log_timezone);
469 :
470 3856 : if (tzn != NULL)
471 3856 : 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 16382 : 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 16382 : if (*newval == NULL)
498 : {
499 : Assert(source == PGC_S_DEFAULT);
500 4480 : return true;
501 : }
502 :
503 : /* OK, load the file and produce a guc_malloc'd TimeZoneAbbrevTable */
504 11902 : *extra = load_tzoffsets(*newval);
505 :
506 : /* tzparser.c returns NULL on failure, reporting via GUC_check_errmsg */
507 11902 : if (!*extra)
508 0 : return false;
509 :
510 11902 : return true;
511 : }
512 :
513 : /*
514 : * GUC assign_hook for assign_timezone_abbreviations
515 : */
516 : void
517 16204 : assign_timezone_abbreviations(const char *newval, void *extra)
518 : {
519 : /* Do nothing for the boot_val default of NULL */
520 16204 : if (!extra)
521 4480 : return;
522 :
523 11724 : 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 10332 : check_transaction_read_only(bool *newval, void **extra, GucSource source)
545 : {
546 10332 : if (*newval == false && XactReadOnly && IsTransactionState() && !InitializingParallelWorker)
547 : {
548 : /* Can't go to r/w mode inside a r/o transaction */
549 64 : 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 52 : 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 46 : 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 10314 : 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 15616 : check_transaction_isolation(int *newval, void **extra, GucSource source)
584 : {
585 15616 : int newXactIsoLevel = *newval;
586 :
587 15616 : if (newXactIsoLevel != XactIsoLevel && IsTransactionState())
588 : {
589 5790 : 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 5788 : 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 5788 : 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 15614 : return true;
613 : }
614 :
615 : /*
616 : * SET TRANSACTION [NOT] DEFERRABLE
617 : */
618 :
619 : bool
620 9014 : check_transaction_deferrable(bool *newval, void **extra, GucSource source)
621 : {
622 9014 : 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 9014 : 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 9014 : 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 1852 : check_random_seed(double *newval, void **extra, GucSource source)
649 : {
650 1852 : *extra = guc_malloc(LOG, sizeof(int));
651 1852 : if (!*extra)
652 0 : return false;
653 : /* Arm the assign only if source of value is an interactive SET */
654 1852 : *((int *) *extra) = (source >= PGC_S_INTERACTIVE);
655 :
656 1852 : return true;
657 : }
658 :
659 : void
660 1852 : assign_random_seed(double newval, void *extra)
661 : {
662 : /* We'll do this at most once for any setting of the GUC variable */
663 1852 : if (*((int *) extra))
664 0 : DirectFunctionCall1(setseed, Float8GetDatum(newval));
665 1852 : *((int *) extra) = 0;
666 1852 : }
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 32882 : 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 32882 : encoding = pg_valid_client_encoding(*newval);
687 32882 : if (encoding < 0)
688 0 : return false;
689 :
690 : /* Get the canonical name (no aliases, uniform case) */
691 32882 : 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 32882 : 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 32882 : if (strcmp(*newval, canonical_name) != 0 &&
736 34 : strcmp(*newval, "UNICODE") != 0)
737 : {
738 34 : guc_free(*newval);
739 34 : *newval = guc_strdup(LOG, canonical_name);
740 34 : 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 32882 : *extra = guc_malloc(LOG, sizeof(int));
748 32882 : if (!*extra)
749 0 : return false;
750 32882 : *((int *) *extra) = encoding;
751 :
752 32882 : return true;
753 : }
754 :
755 : void
756 32694 : assign_client_encoding(const char *newval, void *extra)
757 : {
758 32694 : 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 32694 : 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 7884 : if (InitializingParallelWorker)
772 7884 : 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 24810 : 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 33808 : 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 33808 : if (*newval == NULL)
812 4480 : return true;
813 :
814 29328 : 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 : /*
825 : * When source == PGC_S_TEST, we don't throw a hard error for a
826 : * nonexistent user name or insufficient privileges, only a NOTICE. See
827 : * comments in guc.h.
828 : */
829 :
830 : /* Look up the username */
831 29328 : roleTup = SearchSysCache1(AUTHNAME, PointerGetDatum(*newval));
832 29328 : if (!HeapTupleIsValid(roleTup))
833 : {
834 0 : if (source == PGC_S_TEST)
835 : {
836 0 : ereport(NOTICE,
837 : (errcode(ERRCODE_UNDEFINED_OBJECT),
838 : errmsg("role \"%s\" does not exist", *newval)));
839 0 : return true;
840 : }
841 0 : GUC_check_errmsg("role \"%s\" does not exist", *newval);
842 0 : return false;
843 : }
844 :
845 29328 : roleform = (Form_pg_authid) GETSTRUCT(roleTup);
846 29328 : roleid = roleform->oid;
847 29328 : is_superuser = roleform->rolsuper;
848 :
849 29328 : ReleaseSysCache(roleTup);
850 :
851 : /*
852 : * Only superusers may SET SESSION AUTHORIZATION a role other than itself.
853 : * Note that in case of multiple SETs in a single session, the original
854 : * authenticated user's superuserness is what matters.
855 : */
856 29328 : if (roleid != GetAuthenticatedUserId() &&
857 2560 : !superuser_arg(GetAuthenticatedUserId()))
858 : {
859 0 : if (source == PGC_S_TEST)
860 : {
861 0 : ereport(NOTICE,
862 : (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
863 : errmsg("permission will be denied to set session authorization \"%s\"",
864 : *newval)));
865 0 : return true;
866 : }
867 0 : GUC_check_errcode(ERRCODE_INSUFFICIENT_PRIVILEGE);
868 0 : GUC_check_errmsg("permission denied to set session authorization \"%s\"",
869 : *newval);
870 0 : return false;
871 : }
872 :
873 : /* Set up "extra" struct for assign_session_authorization to use */
874 29328 : myextra = (role_auth_extra *) guc_malloc(LOG, sizeof(role_auth_extra));
875 29328 : if (!myextra)
876 0 : return false;
877 29328 : myextra->roleid = roleid;
878 29328 : myextra->is_superuser = is_superuser;
879 29328 : *extra = (void *) myextra;
880 :
881 29328 : return true;
882 : }
883 :
884 : void
885 34732 : assign_session_authorization(const char *newval, void *extra)
886 : {
887 34732 : role_auth_extra *myextra = (role_auth_extra *) extra;
888 :
889 : /* Do nothing for the boot_val default of NULL */
890 34732 : if (!myextra)
891 4480 : return;
892 :
893 30252 : SetSessionAuthorization(myextra->roleid, myextra->is_superuser);
894 : }
895 :
896 :
897 : /*
898 : * SET ROLE
899 : *
900 : * The SQL spec requires "SET ROLE NONE" to unset the role, so we hardwire
901 : * a translation of "none" to InvalidOid. Otherwise this is much like
902 : * SET SESSION AUTHORIZATION.
903 : */
904 :
905 : bool
906 2698 : check_role(char **newval, void **extra, GucSource source)
907 : {
908 : HeapTuple roleTup;
909 : Oid roleid;
910 : bool is_superuser;
911 : role_auth_extra *myextra;
912 : Form_pg_authid roleform;
913 :
914 2698 : if (strcmp(*newval, "none") == 0)
915 : {
916 : /* hardwired translation */
917 1852 : roleid = InvalidOid;
918 1852 : is_superuser = false;
919 : }
920 : else
921 : {
922 846 : if (!IsTransactionState())
923 : {
924 : /*
925 : * Can't do catalog lookups, so fail. The result of this is that
926 : * role cannot be set in postgresql.conf, which seems like a good
927 : * thing anyway, so we don't work hard to avoid it.
928 : */
929 0 : return false;
930 : }
931 :
932 : /*
933 : * When source == PGC_S_TEST, we don't throw a hard error for a
934 : * nonexistent user name or insufficient privileges, only a NOTICE.
935 : * See comments in guc.h.
936 : */
937 :
938 : /* Look up the username */
939 846 : roleTup = SearchSysCache1(AUTHNAME, PointerGetDatum(*newval));
940 846 : if (!HeapTupleIsValid(roleTup))
941 : {
942 0 : if (source == PGC_S_TEST)
943 : {
944 0 : ereport(NOTICE,
945 : (errcode(ERRCODE_UNDEFINED_OBJECT),
946 : errmsg("role \"%s\" does not exist", *newval)));
947 0 : return true;
948 : }
949 0 : GUC_check_errmsg("role \"%s\" does not exist", *newval);
950 0 : return false;
951 : }
952 :
953 846 : roleform = (Form_pg_authid) GETSTRUCT(roleTup);
954 846 : roleid = roleform->oid;
955 846 : is_superuser = roleform->rolsuper;
956 :
957 846 : ReleaseSysCache(roleTup);
958 :
959 : /*
960 : * Verify that session user is allowed to become this role, but skip
961 : * this in parallel mode, where we must blindly recreate the parallel
962 : * leader's state.
963 : */
964 846 : if (!InitializingParallelWorker &&
965 846 : !member_can_set_role(GetSessionUserId(), roleid))
966 : {
967 12 : if (source == PGC_S_TEST)
968 : {
969 0 : ereport(NOTICE,
970 : (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
971 : errmsg("permission will be denied to set role \"%s\"",
972 : *newval)));
973 0 : return true;
974 : }
975 12 : GUC_check_errcode(ERRCODE_INSUFFICIENT_PRIVILEGE);
976 12 : GUC_check_errmsg("permission denied to set role \"%s\"",
977 : *newval);
978 12 : return false;
979 : }
980 : }
981 :
982 : /* Set up "extra" struct for assign_role to use */
983 2686 : myextra = (role_auth_extra *) guc_malloc(LOG, sizeof(role_auth_extra));
984 2686 : if (!myextra)
985 0 : return false;
986 2686 : myextra->roleid = roleid;
987 2686 : myextra->is_superuser = is_superuser;
988 2686 : *extra = (void *) myextra;
989 :
990 2686 : return true;
991 : }
992 :
993 : void
994 3290 : assign_role(const char *newval, void *extra)
995 : {
996 3290 : role_auth_extra *myextra = (role_auth_extra *) extra;
997 :
998 3290 : SetCurrentRoleId(myextra->roleid, myextra->is_superuser);
999 3290 : }
1000 :
1001 : const char *
1002 0 : show_role(void)
1003 : {
1004 : /*
1005 : * Check whether SET ROLE is active; if not return "none". This is a
1006 : * kluge to deal with the fact that SET SESSION AUTHORIZATION logically
1007 : * resets SET ROLE to NONE, but we cannot set the GUC role variable from
1008 : * assign_session_authorization (because we haven't got enough info to
1009 : * call set_config_option).
1010 : */
1011 0 : if (!OidIsValid(GetCurrentRoleId()))
1012 0 : return "none";
1013 :
1014 : /* Otherwise we can just use the GUC string */
1015 0 : return role_string ? role_string : "none";
1016 : }
1017 :
1018 :
1019 : /*
1020 : * PATH VARIABLES
1021 : *
1022 : * check_canonical_path is used for log_directory and some other GUCs where
1023 : * all we want to do is canonicalize the represented path name.
1024 : */
1025 :
1026 : bool
1027 3704 : check_canonical_path(char **newval, void **extra, GucSource source)
1028 : {
1029 : /*
1030 : * Since canonicalize_path never enlarges the string, we can just modify
1031 : * newval in-place. But watch out for NULL, which is the default value
1032 : * for external_pid_file.
1033 : */
1034 3704 : if (*newval)
1035 1852 : canonicalize_path(*newval);
1036 3704 : return true;
1037 : }
1038 :
1039 :
1040 : /*
1041 : * MISCELLANEOUS
1042 : */
1043 :
1044 : /*
1045 : * GUC check_hook for application_name
1046 : */
1047 : bool
1048 26196 : check_application_name(char **newval, void **extra, GucSource source)
1049 : {
1050 : char *clean;
1051 : char *ret;
1052 :
1053 : /* Only allow clean ASCII chars in the application name */
1054 26196 : clean = pg_clean_ascii(*newval, MCXT_ALLOC_NO_OOM);
1055 26196 : if (!clean)
1056 0 : return false;
1057 :
1058 26196 : ret = guc_strdup(WARNING, clean);
1059 26196 : if (!ret)
1060 : {
1061 0 : pfree(clean);
1062 0 : return false;
1063 : }
1064 :
1065 26196 : pfree(clean);
1066 26196 : *newval = ret;
1067 26196 : return true;
1068 : }
1069 :
1070 : /*
1071 : * GUC assign_hook for application_name
1072 : */
1073 : void
1074 26168 : assign_application_name(const char *newval, void *extra)
1075 : {
1076 : /* Update the pg_stat_activity view */
1077 26168 : pgstat_report_appname(newval);
1078 26168 : }
1079 :
1080 : /*
1081 : * GUC check_hook for cluster_name
1082 : */
1083 : bool
1084 3056 : check_cluster_name(char **newval, void **extra, GucSource source)
1085 : {
1086 : char *clean;
1087 : char *ret;
1088 :
1089 : /* Only allow clean ASCII chars in the cluster name */
1090 3056 : clean = pg_clean_ascii(*newval, MCXT_ALLOC_NO_OOM);
1091 3056 : if (!clean)
1092 0 : return false;
1093 :
1094 3056 : ret = guc_strdup(WARNING, clean);
1095 3056 : if (!ret)
1096 : {
1097 0 : pfree(clean);
1098 0 : return false;
1099 : }
1100 :
1101 3056 : pfree(clean);
1102 3056 : *newval = ret;
1103 3056 : return true;
1104 : }
1105 :
1106 : /*
1107 : * GUC assign_hook for maintenance_io_concurrency
1108 : */
1109 : void
1110 1852 : assign_maintenance_io_concurrency(int newval, void *extra)
1111 : {
1112 : #ifdef USE_PREFETCH
1113 : /*
1114 : * Reconfigure recovery prefetching, because a setting it depends on
1115 : * changed.
1116 : */
1117 1852 : maintenance_io_concurrency = newval;
1118 1852 : if (AmStartupProcess())
1119 0 : XLogPrefetchReconfigure();
1120 : #endif
1121 1852 : }
1122 :
1123 :
1124 : /*
1125 : * These show hooks just exist because we want to show the values in octal.
1126 : */
1127 :
1128 : /*
1129 : * GUC show_hook for data_directory_mode
1130 : */
1131 : const char *
1132 4528 : show_data_directory_mode(void)
1133 : {
1134 : static char buf[12];
1135 :
1136 4528 : snprintf(buf, sizeof(buf), "%04o", data_directory_mode);
1137 4528 : return buf;
1138 : }
1139 :
1140 : /*
1141 : * GUC show_hook for log_file_mode
1142 : */
1143 : const char *
1144 3856 : show_log_file_mode(void)
1145 : {
1146 : static char buf[12];
1147 :
1148 3856 : snprintf(buf, sizeof(buf), "%04o", Log_file_mode);
1149 3856 : return buf;
1150 : }
1151 :
1152 : /*
1153 : * GUC show_hook for unix_socket_permissions
1154 : */
1155 : const char *
1156 3856 : show_unix_socket_permissions(void)
1157 : {
1158 : static char buf[12];
1159 :
1160 3856 : snprintf(buf, sizeof(buf), "%04o", Unix_socket_permissions);
1161 3856 : return buf;
1162 : }
1163 :
1164 :
1165 : /*
1166 : * These check hooks do nothing more than reject non-default settings
1167 : * in builds that don't support them.
1168 : */
1169 :
1170 : bool
1171 1852 : check_bonjour(bool *newval, void **extra, GucSource source)
1172 : {
1173 : #ifndef USE_BONJOUR
1174 1852 : if (*newval)
1175 : {
1176 0 : GUC_check_errmsg("Bonjour is not supported by this build");
1177 0 : return false;
1178 : }
1179 : #endif
1180 1852 : return true;
1181 : }
1182 :
1183 : bool
1184 1864 : check_default_with_oids(bool *newval, void **extra, GucSource source)
1185 : {
1186 1864 : if (*newval)
1187 : {
1188 : /* check the GUC's definition for an explanation */
1189 6 : GUC_check_errcode(ERRCODE_FEATURE_NOT_SUPPORTED);
1190 6 : GUC_check_errmsg("tables declared WITH OIDS are not supported");
1191 :
1192 6 : return false;
1193 : }
1194 :
1195 1858 : return true;
1196 : }
1197 :
1198 : bool
1199 2446 : check_effective_io_concurrency(int *newval, void **extra, GucSource source)
1200 : {
1201 : #ifndef USE_PREFETCH
1202 : if (*newval != 0)
1203 : {
1204 : GUC_check_errdetail("\"effective_io_concurrency\" must be set to 0 on platforms that lack posix_fadvise().");
1205 : return false;
1206 : }
1207 : #endif /* USE_PREFETCH */
1208 2446 : return true;
1209 : }
1210 :
1211 : bool
1212 1852 : check_maintenance_io_concurrency(int *newval, void **extra, GucSource source)
1213 : {
1214 : #ifndef USE_PREFETCH
1215 : if (*newval != 0)
1216 : {
1217 : GUC_check_errdetail("\"maintenance_io_concurrency\" must be set to 0 on platforms that lack posix_fadvise().");
1218 : return false;
1219 : }
1220 : #endif /* USE_PREFETCH */
1221 1852 : return true;
1222 : }
1223 :
1224 : bool
1225 1904 : check_ssl(bool *newval, void **extra, GucSource source)
1226 : {
1227 : #ifndef USE_SSL
1228 : if (*newval)
1229 : {
1230 : GUC_check_errmsg("SSL is not supported by this build");
1231 : return false;
1232 : }
1233 : #endif
1234 1904 : return true;
1235 : }
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