<!--

$Header: /cvsroot/pgsql/doc/src/sgml/ref/allfiles.sgml,v 1.29 2001/05/0819:28:01 momjian Exp $

$Header: /cvsroot/pgsql/doc/src/sgml/ref/allfiles.sgml,v 1.30 2001/05/0821:06:42 petere Exp $

Postgres documentation

Complete list of usable sgml source files in this directory.

-->

<!entity selectInto system "select_into.sgml">

<!entity set system "set.sgml">

<!entity setConstraints system "set_constraints.sgml">

<!entity setSessionAuth system "set_session_auth.sgml">

<!entity setTransaction system "set_transaction.sgml">

<!entity show system "show.sgml">

<!entity truncate system "truncate.sgml">

<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/set_session_auth.sgml,v 1.1 2001/05/08 21:06:42 petere Exp $ -->

<refentry id="SQL-SET-SESSION-AUTHORIZATION">

<docinfo>

<date>2001-04-21</date>

</docinfo>

<refmeta>

<refentrytitle>SET SESSION AUTHORIZATION</refentrytitle>

<refmiscinfo>SQL - Language Statements</refmiscinfo>

</refmeta>

<refnamediv>

<refname>SET SESSION AUTHORIZATION</refname>

<refpurpose>Set the session user identifier and the current user identifier

of the current SQL-session context</refpurpose>

</refnamediv>

<refsynopsisdiv>

<synopsis>

SET SESSION AUTHORIZATION '<parameter>username</parameter>'

</synopsis>

</refsynopsisdiv>

<refsect1>

<title>Description</title>

<para>

This command sets the session user identifier and the current user

identifer of the current SQL-session context to be

<parameter>username</parameter>.

</para>

<para>

The session user identifier is initially set to be the (possibly

authenticated) user name provided by the client. The current user

identifier is normally equal to the session user identifier, but

may change temporarily in the context of <quote>setuid</quote>

functions and similar mechanisms. The current user identifer is

relevant for permission checking.

</para>

<para>

Execution of this command is only permitted if the initial session

user (the <firstterm>authenticated user</firstterm>) had the

superuser privilege. This permission is kept for the duration of a

connection; for example, it is possible to temporarily become an

unprivileged user and later switch back to become a superuser.

</para>

</refsect1>

<refsect1>

<title>Examples</title>

<screen>

<userinput>SELECT SESSION_USER, CURRENT_USER;</userinput>

current_user | session_user

--------------+--------------

peter | peter

<userinput>SET SESSION AUTHORIZATION 'paul';</userinput>

<userinput>SELECT SESSION_USER, CURRENT_USER;</userinput>

current_user | session_user

--------------+--------------

paul | paul

</screen>

</refsect1>

<refsect1>

<title>Compatibility</title>

<simpara>SQL99</simpara>

<para>

SQL99 allows some other expressions to appear in place of the

literal <parameter>username</parameter> which are not important in

practice. <application>PostgreSQL</application> allows identifier

syntax (<literal>"username"</literal>), which SQL does not. SQL

does not allow this command during a transaction;

<application>PostgreSQL</application> does not make

this restriction because there is no reason to. The

privileges necessary to execute this command are left

implementation-defined by the standard.

</para>

</refsect1>

</refentry>

<!-- Keep this comment at the end of the file

Local variables:

mode:sgml

sgml-omittag:nil

sgml-shorttag:t

sgml-minimize-attributes:nil

sgml-always-quote-attributes:t

sgml-indent-step:1

sgml-indent-data:t

sgml-parent-document:nil

sgml-default-dtd-file:"../reference.ced"

sgml-exposed-tags:nil

sgml-local-catalogs:("/usr/lib/sgml/catalog")

sgml-local-ecat-files:nil

End:

-->

<!-- reference.sgml

$Header: /cvsroot/pgsql/doc/src/sgml/reference.sgml,v 1.16 2001/05/07 00:43:14 tgl Exp $

$Header: /cvsroot/pgsql/doc/src/sgml/reference.sgml,v 1.17 2001/05/08 21:06:42 petere Exp $

PostgreSQL Reference Manual

-->

&selectInto;

&set;

&setConstraints;

&setSessionAuth;

&setTransaction;

&show;

&truncate;

&dropuser;

&ecpgRef;

&pgAccess;

&pgAdmin;

&pgConfig;

&pgDump;

&pgDumpall;

parse_server_encoding(mvalue);

elseif (strcasecmp(name,"seed")==0)

parse_random_seed(mvalue);

elseif (strcasecmp(name,"session_authorization")==0)

SetSessionAuthorization(value);

SetConfigOption(name,value,superuser() ?PGC_SUSET :PGC_USERSET);

%type<str>Sconst,comment_text

%type<str>UserId,opt_boolean,var_value,zone_value

%type<str>UserId,opt_boolean,var_value,zone_value,Ident_or_Sconst

%type<str>ColId,ColLabel,TokenId

%tokenABSOLUTE,ACTION,ADD,ALL,ALTER,AND,ANY,AS,ASC,AT,

%tokenABSOLUTE,ACTION,ADD,ALL,ALTER,AND,ANY,AS,ASC,AT,AUTHORIZATION,

BEGIN_TRANS,BETWEEN,BOTH,BY,

CASCADE,CASE,CAST,CHAR,CHARACTER,CHECK,CLOSE,

COALESCE,COLLATE,COLUMN,COMMIT,

n->value =$3;

$$ = (Node *) n;

}

{

VariableSetStmt *n = makeNode(VariableSetStmt);

n->name ="session_authorization";

n->value =$4;

$$ = (Node *) n;

}

;

opt_level:READCOMMITTED{$$ ="committed"; }

|/*EMPTY*/{$$ =NULL; }

;

Ident_or_Sconst:IDENT{$$ =$1; }

|SCONST{$$ =$1; }

VariableShowStmt:SHOWColId

{

VariableShowStmt *n = makeNode(VariableShowStmt);

|AGGREGATE{$$ ="aggregate"; }

|ALTER{$$ ="alter"; }

|AT{$$ ="at"; }

|AUTHORIZATION{$$ ="authorization"; }

|BACKWARD{$$ ="backward"; }

|BEFORE{$$ ="before"; }

|BEGIN_TRANS{$$ ="begin"; }

{"as",AS},

{"asc",ASC},

{"at",AT},

{"authorization",AUTHORIZATION},

{"backward",BACKWARD},

{"before",BEFORE},

{"begin",BEGIN_TRANS},

staticOidCurrentUserId=InvalidOid;

staticOidSessionUserId=InvalidOid;

staticboolAuthenticatedUserIsSuperuser= false;

SetSessionUserIdFromUserName(constchar*username)

InitializeSessionUserId(constchar*username)

{

HeapTupleuserTup;

AssertState(!IsBootstrapProcessingMode());

AssertState(!OidIsValid(SessionUserId));

userTup=SearchSysCache(SHADOWNAME,

PointerGetDatum(username),

0,0,0);

SetSessionUserId(((Form_pg_shadow)GETSTRUCT(userTup))->usesysid);

AuthenticatedUserIsSuperuser= ((Form_pg_shadow)GETSTRUCT(userTup))->usesuper;

ReleaseSysCache(userTup);

}

voidSetSessionAuthorization(constchar*username)

{

HeapTupleuserTup;

if (!AuthenticatedUserIsSuperuser)

elog(ERROR,"permission denied");

userTup=SearchSysCache(SHADOWNAME,

PointerGetDatum(username),

0,0,0);

if (!HeapTupleIsValid(userTup))

elog(ERROR,"user \"%s\" does not exist",username);

SetSessionUserId(((Form_pg_shadow)GETSTRUCT(userTup))->usesysid);

SetUserId(((Form_pg_shadow)GETSTRUCT(userTup))->usesysid);

ReleaseSysCache(userTup);

}

if (bootstrap)

SetSessionUserId(geteuid());

SetSessionUserIdFromUserName(username);

InitializeSessionUserId(username);

"CONSTRAINTS",

"NAMES",

"SESSION CHARACTERISTICS AS TRANSACTION ISOLATION LEVEL",

"SESSION",

"TRANSACTION ISOLATION LEVEL",

"DateStyle",

COMPLETE_WITH_LIST(constraint_list);

}

elseif (strcasecmp(prev2_wd,"SET")==0&&strcasecmp(prev_wd,"SESSION")==0)

{

char*my_list[]= {"AUTHORIZATION",

"CHARACTERISTICS AS TRANSACTION ISOLATION LEVEL",

NULL};

COMPLETE_WITH_LIST(my_list);

}

elseif (strcasecmp(prev3_wd,"SET")==0

&&strcasecmp(prev2_wd,"SESSION")==0

&&strcasecmp(prev_wd,"AUTHORIZATION")==0)

{

COMPLETE_WITH_QUERY(Query_for_list_of_users);

}

elseif (strcasecmp(prev2_wd,"SET")==0&&

strcasecmp(prev4_wd,"UPDATE")!=0)

externvoidSetUserId(Oiduserid);

externOidGetSessionUserId(void);

externvoidSetSessionUserId(Oiduserid);

externvoidSetSessionUserIdFromUserName(constchar*username);

externvoidInitializeSessionUserId(constchar*username);

externvoidSetSessionAuthorization(constchar*username);

externvoidSetDataDir(constchar*dir);