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postgresql/src/backend/commands/variable.c

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/*-------------------------------------------------------------------------
*
* variable.c
* Routines for handling of 'SET var TO',
* 'SHOW var' and 'RESET var' statements.
*
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/variable.c,v 1.61 2002/03/29 19:06:07 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <ctype.h>
#include <time.h>
#include "access/xact.h"
#include "catalog/pg_shadow.h"
#include "catalog/pg_type.h"
#include "commands/variable.h"
#include "miscadmin.h"
#include "optimizer/cost.h"
#include "optimizer/paths.h"
#include "parser/parse_type.h"
#include "utils/builtins.h"
#include "utils/date.h"
#include "utils/guc.h"
#include "utils/tqual.h"
#ifdef MULTIBYTE
#include "mb/pg_wchar.h"
#else
/* Grand unified hard-coded badness */
#define pg_get_client_encoding_name() "SQL_ASCII"
#define GetDatabaseEncodingName() "SQL_ASCII"
#endif
static bool show_datestyle(void);
static bool reset_datestyle(void);
static bool parse_datestyle(List *);
static bool show_timezone(void);
static bool reset_timezone(void);
static bool parse_timezone(List *);
static bool show_XactIsoLevel(void);
static bool reset_XactIsoLevel(void);
static bool parse_XactIsoLevel(List *);
static bool show_random_seed(void);
static bool reset_random_seed(void);
static bool parse_random_seed(List *);
static bool show_client_encoding(void);
static bool reset_client_encoding(void);
static bool parse_client_encoding(List *);
static bool show_server_encoding(void);
static bool reset_server_encoding(void);
static bool parse_server_encoding(List *);
/*
* get_token
* Obtain the next item in a comma-separated list of items,
* where each item can be either "word" or "word=word".
* The "word=word" form is only accepted if 'val' is not NULL.
* Words are any sequences not containing whitespace, ',', or '='.
* Whitespace can appear between the words and punctuation.
*
* 'tok': receives a pointer to first word of item, or NULL if none.
* 'val': if not NULL, receives a pointer to second word, or NULL if none.
* 'str': start of input string.
*
* Returns NULL if input string contained no more words, else pointer
* to just past this item, which can be used as 'str' for next call.
* (If this is the last item, returned pointer will point at a null char,
* so caller can alternatively check for that instead of calling again.)
*
* NB: input string is destructively modified by placing null characters
* at ends of words!
*
* A former version of this code avoided modifying the input string by
* returning palloc'd copies of the words. However, we want to use this
* code early in backend startup to parse the PGDATESTYLE environment var,
* and palloc/pfree aren't initialized at that point. Cleanest answer
* seems to be to palloc in SetPGVariable() so that we can treat the string
* as modifiable here.
*/
static char *
get_token(char **tok, char **val, char *str)
{
char ch;
*tok = NULL;
if (val != NULL)
*val = NULL;
if (!str || *str == '\0')
return NULL;
/* skip leading white space */
while (isspace((unsigned char) *str))
str++;
/* end of string? then return NULL */
if (*str == '\0')
return NULL;
if (*str == ',' || *str == '=')
elog(ERROR, "Syntax error near \"%s\": empty setting", str);
/* OK, at beginning of non-empty item */
*tok = str;
/* Advance to end of word */
while (*str && !isspace((unsigned char) *str) &&
*str != ',' && *str != '=')
str++;
/* Terminate word string for caller */
ch = *str;
*str = '\0';
/* Skip any whitespace */
while (isspace((unsigned char) ch))
ch = *(++str);
/* end of string? */
if (ch == '\0')
return str;
/* delimiter? */
if (ch == ',')
return ++str;
/* Had better be '=', and caller must be expecting it */
if (val == NULL || ch != '=')
elog(ERROR, "Syntax error near \"%s\"", str);
/* '=': get the value */
str++;
/* skip whitespace after '=' */
while (isspace((unsigned char) *str))
str++;
if (*str == ',' || *str == '\0')
elog(ERROR, "Syntax error near \"=%s\"", str);
/* OK, at beginning of non-empty value */
*val = str;
/* Advance to end of word */
while (*str && !isspace((unsigned char) *str) && *str != ',')
str++;
/* Terminate word string for caller */
ch = *str;
*str = '\0';
/* Skip any whitespace */
while (isspace((unsigned char) ch))
ch = *(++str);
/* end of string? */
if (ch == '\0')
return str;
/* delimiter? */
if (ch == ',')
return ++str;
elog(ERROR, "Syntax error near \"%s\"", str);
return str;
}
/*
* DATESTYLE
*
* NOTE: set_default_datestyle() is called during backend startup to check
* if the PGDATESTYLE environment variable is set. We want the env var
* to determine the value that "RESET DateStyle" will reset to!
*/
/* These get initialized from the "master" values in init/globals.c */
static int DefaultDateStyle;
static bool DefaultEuroDates;
static bool
parse_datestyle_internal(char *value)
{
char *tok;
int dcnt = 0,
ecnt = 0;
if (value == NULL)
return reset_datestyle();
while ((value = get_token(&tok, NULL, value)) != 0)
{
/* Ugh. Somebody ought to write a table driven version -- mjl */
if (!strcasecmp(tok, "ISO"))
{
DateStyle = USE_ISO_DATES;
dcnt++;
}
else if (!strcasecmp(tok, "SQL"))
{
DateStyle = USE_SQL_DATES;
dcnt++;
}
else if (!strncasecmp(tok, "POSTGRESQL", 8))
{
DateStyle = USE_POSTGRES_DATES;
dcnt++;
}
else if (!strcasecmp(tok, "GERMAN"))
{
DateStyle = USE_GERMAN_DATES;
dcnt++;
EuroDates = TRUE;
if ((ecnt > 0) && (!EuroDates))
ecnt++;
}
else if (!strncasecmp(tok, "EURO", 4))
{
EuroDates = TRUE;
if ((dcnt <= 0) || (DateStyle != USE_GERMAN_DATES))
ecnt++;
}
else if ((!strcasecmp(tok, "US"))
|| (!strncasecmp(tok, "NONEURO", 7)))
{
EuroDates = FALSE;
if ((dcnt <= 0) || (DateStyle == USE_GERMAN_DATES))
ecnt++;
}
else if (!strcasecmp(tok, "DEFAULT"))
{
DateStyle = DefaultDateStyle;
EuroDates = DefaultEuroDates;
ecnt++;
}
else
elog(ERROR, "Bad value for date style (%s)", tok);
}
if (dcnt > 1 || ecnt > 1)
elog(WARNING, "Conflicting settings for date");
return TRUE;
}
static bool
parse_datestyle(List *args)
{
char *value;
if (args == NULL)
return reset_datestyle();
Assert(IsA(lfirst(args), A_Const));
value = ((A_Const *) lfirst(args))->val.val.str;
return parse_datestyle_internal(value);
}
static bool
show_datestyle(void)
{
char buf[64];
strcpy(buf, "DateStyle is ");
switch (DateStyle)
{
case USE_ISO_DATES:
strcat(buf, "ISO");
break;
case USE_SQL_DATES:
strcat(buf, "SQL");
break;
case USE_GERMAN_DATES:
strcat(buf, "German");
break;
default:
strcat(buf, "Postgres");
break;
};
strcat(buf, " with ");
strcat(buf, ((EuroDates) ? "European" : "US (NonEuropean)"));
strcat(buf, " conventions");
elog(INFO, buf, NULL);
return TRUE;
}
static bool
reset_datestyle(void)
{
DateStyle = DefaultDateStyle;
EuroDates = DefaultEuroDates;
return TRUE;
}
void
set_default_datestyle(void)
{
char *DBDate;
/*
* Initialize from compile-time defaults in init/globals.c. NB: this
* is a necessary step; consider PGDATESTYLE="DEFAULT".
*/
DefaultDateStyle = DateStyle;
DefaultEuroDates = EuroDates;
/* If the environment var is set, override compiled-in values */
DBDate = getenv("PGDATESTYLE");
if (DBDate == NULL)
return;
/*
* Make a modifiable copy --- overwriting the env var doesn't seem
* like a good idea, even though we currently won't look at it again.
* Note that we cannot use palloc at this early stage of
* initialization.
*/
DBDate = strdup(DBDate);
/*
* Parse desired setting into DateStyle/EuroDates Use
* parse_datestyle_internal() to avoid any palloc() issues per above -
* thomas 2001-10-15
*/
parse_datestyle_internal(DBDate);
free(DBDate);
/* And make it the default for future RESETs */
DefaultDateStyle = DateStyle;
DefaultEuroDates = EuroDates;
}
/* Timezone support
* Working storage for strings is allocated with an arbitrary size of 64 bytes.
*/
static char *defaultTZ = NULL;
static char TZvalue[64];
static char tzbuf[64];
/*
*
* TIMEZONE
*
*/
/* parse_timezone()
* Handle SET TIME ZONE...
* Try to save existing TZ environment variable for later use in RESET TIME ZONE.
* Accept an explicit interval per SQL9x, though this is less useful than a full time zone.
* - thomas 2001-10-11
*/
static bool
parse_timezone(List *args)
{
List *arg;
TypeName *type;
if (args == NULL)
return reset_timezone();
Assert(IsA(args, List));
foreach(arg, args)
{
A_Const *p;
Assert(IsA(arg, List));
p = lfirst(arg);
Assert(IsA(p, A_Const));
type = p->typename;
if (type != NULL)
{
Oid typeOid = typenameTypeId(type);
if (typeOid == INTERVALOID)
{
Interval *interval;
interval = DatumGetIntervalP(DirectFunctionCall3(interval_in,
CStringGetDatum(p->val.val.str),
ObjectIdGetDatum(InvalidOid),
Int32GetDatum(type->typmod)));
if (interval->month != 0)
elog(ERROR, "SET TIME ZONE illegal INTERVAL; month not allowed");
CTimeZone = interval->time;
}
else if (typeOid == FLOAT8OID)
{
float8 time;
time = DatumGetFloat8(DirectFunctionCall1(float8in, CStringGetDatum(p->val.val.str)));
CTimeZone = time * 3600;
}
/*
* We do not actually generate an integer constant in gram.y
* so this is not used...
*/
else if (typeOid == INT4OID)
{
int32 time;
time = p->val.val.ival;
CTimeZone = time * 3600;
}
else
{
elog(ERROR, "Unable to process SET TIME ZONE command; internal coding error");
}
HasCTZSet = true;
}
else
{
char *tok;
char *value;
value = p->val.val.str;
while ((value = get_token(&tok, NULL, value)) != 0)
{
/* Not yet tried to save original value from environment? */
if (defaultTZ == NULL)
{
/* found something? then save it for later */
if ((defaultTZ = getenv("TZ")) != NULL)
strcpy(TZvalue, defaultTZ);
/* found nothing so mark with an invalid pointer */
else
defaultTZ = (char *) -1;
}
strcpy(tzbuf, "TZ=");
strcat(tzbuf, tok);
if (putenv(tzbuf) != 0)
elog(ERROR, "Unable to set TZ environment variable to %s", tok);
tzset();
}
HasCTZSet = false;
}
}
return TRUE;
} /* parse_timezone() */
static bool
show_timezone(void)
{
char *tzn;
if (HasCTZSet)
{
Interval interval;
interval.month = 0;
interval.time = CTimeZone;
tzn = DatumGetCString(DirectFunctionCall1(interval_out, IntervalPGetDatum(&interval)));
}
else
tzn = getenv("TZ");
if (tzn != NULL)
elog(INFO, "Time zone is '%s'", tzn);
else
elog(INFO, "Time zone is unset");
return TRUE;
} /* show_timezone() */
/* reset_timezone()
* Set TZ environment variable to original value.
* Note that if TZ was originally not set, TZ should be cleared.
* unsetenv() works fine, but is BSD, not POSIX, and is not available
* under Solaris, among others. Apparently putenv() called as below
* clears the process-specific environment variables.
* Other reasonable arguments to putenv() (e.g. "TZ=", "TZ", "") result
* in a core dump (under Linux anyway).
* - thomas 1998-01-26
*/
static bool
reset_timezone(void)
{
if (HasCTZSet)
HasCTZSet = false;
/* no time zone has been set in this session? */
else if (defaultTZ == NULL)
{
}
/* time zone was set and original explicit time zone available? */
else if (defaultTZ != (char *) -1)
{
strcpy(tzbuf, "TZ=");
strcat(tzbuf, TZvalue);
if (putenv(tzbuf) != 0)
elog(ERROR, "Unable to set TZ environment variable to %s", TZvalue);
tzset();
}
/*
* otherwise, time zone was set but no original explicit time zone
* available
*/
else
{
strcpy(tzbuf, "=");
if (putenv(tzbuf) != 0)
elog(ERROR, "Unable to clear TZ environment variable");
tzset();
}
return TRUE;
} /* reset_timezone() */
/*
*
* SET TRANSACTION
*
*/
static bool
parse_XactIsoLevel(List *args)
{
char *value;
if (args == NULL)
return reset_XactIsoLevel();
Assert(IsA(lfirst(args), A_Const));
value = ((A_Const *) lfirst(args))->val.val.str;
if (SerializableSnapshot != NULL)
{
elog(ERROR, "SET TRANSACTION ISOLATION LEVEL must be called before any query");
return TRUE;
}
if (strcmp(value, "serializable") == 0)
XactIsoLevel = XACT_SERIALIZABLE;
else if (strcmp(value, "read committed") == 0)
XactIsoLevel = XACT_READ_COMMITTED;
else
elog(ERROR, "invalid transaction isolation level: %s", value);
return TRUE;
}
static bool
show_XactIsoLevel(void)
{
if (XactIsoLevel == XACT_SERIALIZABLE)
elog(INFO, "TRANSACTION ISOLATION LEVEL is SERIALIZABLE");
else
elog(INFO, "TRANSACTION ISOLATION LEVEL is READ COMMITTED");
return TRUE;
}
static bool
reset_XactIsoLevel(void)
{
if (SerializableSnapshot != NULL)
{
elog(ERROR, "SET TRANSACTION ISOLATION LEVEL must be called before any query");
return TRUE;
}
XactIsoLevel = DefaultXactIsoLevel;
return TRUE;
}
/*
* Random number seed
*/
static bool
parse_random_seed(List *args)
{
char *value;
double seed = 0;
if (args == NULL)
return reset_random_seed();
Assert(IsA(lfirst(args), A_Const));
value = ((A_Const *) lfirst(args))->val.val.str;
sscanf(value, "%lf", &seed);
DirectFunctionCall1(setseed, Float8GetDatum(seed));
return (TRUE);
}
static bool
show_random_seed(void)
{
elog(INFO, "Seed for random number generator is unavailable");
return (TRUE);
}
static bool
reset_random_seed(void)
{
double seed = 0.5;
DirectFunctionCall1(setseed, Float8GetDatum(seed));
return (TRUE);
}
/*
* MULTIBYTE-related functions
*
* If MULTIBYTE support was not compiled, we still allow these variables
* to exist, but you can't set them to anything but "SQL_ASCII". This
* minimizes interoperability problems between non-MB servers and MB-enabled
* clients.
*/
static bool
parse_client_encoding(List *args)
{
char *value;
#ifdef MULTIBYTE
int encoding;
#endif
if (args == NULL)
return reset_client_encoding();
Assert(IsA(lfirst(args), A_Const));
value = ((A_Const *) lfirst(args))->val.val.str;
#ifdef MULTIBYTE
encoding = pg_valid_client_encoding(value);
if (encoding < 0)
{
if (value)
elog(ERROR, "Client encoding '%s' is not supported", value);
else
elog(ERROR, "No client encoding is specified");
}
else
{
if (pg_set_client_encoding(encoding) < 0)
{
elog(ERROR, "Conversion between %s and %s is not supported",
value, GetDatabaseEncodingName());
}
}
#else
if (value &&
strcasecmp(value, pg_get_client_encoding_name()) != 0)
elog(ERROR, "Client encoding %s is not supported", value);
#endif
return TRUE;
}
static bool
show_client_encoding(void)
{
elog(INFO, "Current client encoding is '%s'",
pg_get_client_encoding_name());
return TRUE;
}
static bool
reset_client_encoding(void)
{
#ifdef MULTIBYTE
int encoding;
char *env = getenv("PGCLIENTENCODING");
if (env)
{
encoding = pg_char_to_encoding(env);
if (encoding < 0)
encoding = GetDatabaseEncoding();
}
else
encoding = GetDatabaseEncoding();
pg_set_client_encoding(encoding);
#endif
return TRUE;
}
/* Called during MULTIBYTE backend startup ... */
void
set_default_client_encoding(void)
{
reset_client_encoding();
}
static bool
parse_server_encoding(List *args)
{
elog(INFO, "SET SERVER_ENCODING is not supported");
return TRUE;
}
static bool
show_server_encoding(void)
{
elog(INFO, "Current server encoding is '%s'", GetDatabaseEncodingName());
return TRUE;
}
static bool
reset_server_encoding(void)
{
elog(INFO, "RESET SERVER_ENCODING is not supported");
return TRUE;
}
/* SetPGVariable()
* Dispatcher for handling SET commands.
* Special cases ought to be removed and handled separately by TCOP
*/
void
SetPGVariable(const char *name, List *args)
{
if (strcasecmp(name, "datestyle") == 0)
parse_datestyle(args);
else if (strcasecmp(name, "timezone") == 0)
parse_timezone(args);
else if (strcasecmp(name, "XactIsoLevel") == 0)
parse_XactIsoLevel(args);
else if (strcasecmp(name, "client_encoding") == 0)
parse_client_encoding(args);
else if (strcasecmp(name, "server_encoding") == 0)
parse_server_encoding(args);
else if (strcasecmp(name, "seed") == 0)
parse_random_seed(args);
else
{
/*
* For routines defined somewhere else, go ahead and extract the
* string argument to match the original interface definition.
* Later, we can change this code too...
*/
char *value;
value = ((args != NULL) ? ((A_Const *) lfirst(args))->val.val.str : NULL);
if (strcasecmp(name, "session_authorization") == 0)
SetSessionAuthorization(value);
else
SetConfigOption(name, value, superuser() ? PGC_SUSET : PGC_USERSET, PGC_S_SESSION);
}
return;
}
void
GetPGVariable(const char *name)
{
if (strcasecmp(name, "datestyle") == 0)
show_datestyle();
else if (strcasecmp(name, "timezone") == 0)
show_timezone();
else if (strcasecmp(name, "XactIsoLevel") == 0)
show_XactIsoLevel();
else if (strcasecmp(name, "client_encoding") == 0)
show_client_encoding();
else if (strcasecmp(name, "server_encoding") == 0)
show_server_encoding();
else if (strcasecmp(name, "seed") == 0)
show_random_seed();
else if (strcasecmp(name, "all") == 0)
{
ShowAllGUCConfig();
show_datestyle();
show_timezone();
show_XactIsoLevel();
show_client_encoding();
show_server_encoding();
show_random_seed();
}
else
{
const char *val = GetConfigOption(name);
elog(INFO, "%s is %s", name, val);
}
}
void
ResetPGVariable(const char *name)
{
if (strcasecmp(name, "datestyle") == 0)
reset_datestyle();
else if (strcasecmp(name, "timezone") == 0)
reset_timezone();
else if (strcasecmp(name, "XactIsoLevel") == 0)
reset_XactIsoLevel();
else if (strcasecmp(name, "client_encoding") == 0)
reset_client_encoding();
else if (strcasecmp(name, "server_encoding") == 0)
reset_server_encoding();
else if (strcasecmp(name, "seed") == 0)
reset_random_seed();
else if (strcasecmp(name, "all") == 0)
{
reset_random_seed();
/* reset_server_encoding(); */
reset_client_encoding();
reset_datestyle();
reset_timezone();
ResetAllOptions(false);
}
else
SetConfigOption(name, NULL,
superuser() ? PGC_SUSET : PGC_USERSET,
PGC_S_SESSION);
}
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