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postgresql/contrib/dblink/dblink.c
Joe Conway d92583f88e Restrict non-superusers to password authenticated connections 
to prevent possible escalation of privilege. Provide new SECURITY
DEFINER functions with old behavior, but initially REVOKE ALL
from public for these functions. Per list discussion and design
proposed by Tom Lane. A different approach will be used for
back-branches, committed separately.
2007-07-08 17:12:38 +00:00

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/*
* dblink.c
*
* Functions returning results from a remote database
*
* Joe Conway <mail@joeconway.com>
* And contributors:
* Darko Prenosil <Darko.Prenosil@finteh.hr>
* Shridhar Daithankar <shridhar_daithankar@persistent.co.in>
*
* $PostgreSQL: pgsql/contrib/dblink/dblink.c,v 1.64 2007/07/08 17:12:38 joe Exp $
* Copyright (c) 2001-2007, PostgreSQL Global Development Group
* ALL RIGHTS RESERVED;
*
* Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose, without fee, and without a written agreement
* is hereby granted, provided that the above copyright notice and this
* paragraph and the following two paragraphs appear in all copies.
*
* IN NO EVENT SHALL THE AUTHOR OR DISTRIBUTORS BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
* LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
* DOCUMENTATION, EVEN IF THE AUTHOR OR DISTRIBUTORS HAVE BEEN ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* THE AUTHOR AND DISTRIBUTORS SPECIFICALLY DISCLAIMS ANY WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE AUTHOR AND DISTRIBUTORS HAS NO OBLIGATIONS TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*
*/
#include "postgres.h"
#include <limits.h>
#include "libpq-fe.h"
#include "fmgr.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "access/heapam.h"
#include "access/tupdesc.h"
#include "catalog/namespace.h"
#include "catalog/pg_index.h"
#include "catalog/pg_type.h"
#include "executor/executor.h"
#include "executor/spi.h"
#include "lib/stringinfo.h"
#include "nodes/execnodes.h"
#include "nodes/nodes.h"
#include "nodes/pg_list.h"
#include "parser/parse_type.h"
#include "tcop/tcopprot.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/dynahash.h"
#include "utils/fmgroids.h"
#include "utils/hsearch.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
#include "utils/memutils.h"
#include "dblink.h"
PG_MODULE_MAGIC;
typedef struct remoteConn
{
PGconn *conn; /* Hold the remote connection */
int openCursorCount; /* The number of open cursors */
bool newXactForCursor; /* Opened a transaction for a cursor */
} remoteConn;
/*
* Internal declarations
*/
static Datum dblink_record_internal(FunctionCallInfo fcinfo, bool is_async, bool do_get);
static remoteConn *getConnectionByName(const char *name);
static HTAB *createConnHash(void);
static void createNewConnection(const char *name, remoteConn * rconn);
static void deleteConnection(const char *name);
static char **get_pkey_attnames(Oid relid, int16 *numatts);
static char **get_text_array_contents(ArrayType *array, int *numitems);
static char *get_sql_insert(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals, char **tgt_pkattvals);
static char *get_sql_delete(Oid relid, int2vector *pkattnums, int16 pknumatts, char **tgt_pkattvals);
static char *get_sql_update(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals, char **tgt_pkattvals);
static char *quote_literal_cstr(char *rawstr);
static char *quote_ident_cstr(char *rawstr);
static int16 get_attnum_pk_pos(int2vector *pkattnums, int16 pknumatts, int16 key);
static HeapTuple get_tuple_of_interest(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals);
static Oid get_relid_from_relname(text *relname_text);
static char *generate_relation_name(Oid relid);
/* Global */
static remoteConn *pconn = NULL;
static HTAB *remoteConnHash = NULL;
/*
* Following is list that holds multiple remote connections.
* Calling convention of each dblink function changes to accept
* connection name as the first parameter. The connection list is
* much like ecpg e.g. a mapping between a name and a PGconn object.
*/
typedef struct remoteConnHashEnt
{
char name[NAMEDATALEN];
remoteConn *rconn;
} remoteConnHashEnt;
/* initial number of connection hashes */
#define NUMCONN 16
/* general utility */
#define GET_TEXT(cstrp) DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(cstrp)))
#define GET_STR(textp) DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(textp)))
#define xpfree(var_) \
do { \
if (var_ != NULL) \
{ \
pfree(var_); \
var_ = NULL; \
} \
} while (0)
#define DBLINK_RES_INTERNALERROR(p2) \
do { \
msg = pstrdup(PQerrorMessage(conn)); \
if (res) \
PQclear(res); \
elog(ERROR, "%s: %s", p2, msg); \
} while (0)
#define DBLINK_RES_ERROR(p2) \
do { \
msg = pstrdup(PQerrorMessage(conn)); \
if (res) \
PQclear(res); \
ereport(ERROR, \
(errcode(ERRCODE_SYNTAX_ERROR), \
errmsg("%s", p2), \
errdetail("%s", msg))); \
} while (0)
#define DBLINK_RES_ERROR_AS_NOTICE(p2) \
do { \
msg = pstrdup(PQerrorMessage(conn)); \
if (res) \
PQclear(res); \
ereport(NOTICE, \
(errcode(ERRCODE_SYNTAX_ERROR), \
errmsg("%s", p2), \
errdetail("%s", msg))); \
} while (0)
#define DBLINK_CONN_NOT_AVAIL \
do { \
if(conname) \
ereport(ERROR, \
(errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST), \
errmsg("connection \"%s\" not available", conname))); \
else \
ereport(ERROR, \
(errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST), \
errmsg("connection not available"))); \
} while (0)
#define DBLINK_GET_CONN \
do { \
char *conname_or_str = GET_STR(PG_GETARG_TEXT_P(0)); \
rconn = getConnectionByName(conname_or_str); \
if(rconn) \
{ \
conn = rconn->conn; \
} \
else \
{ \
connstr = conname_or_str; \
conn = PQconnectdb(connstr); \
if (PQstatus(conn) == CONNECTION_BAD) \
{ \
msg = pstrdup(PQerrorMessage(conn)); \
PQfinish(conn); \
ereport(ERROR, \
(errcode(ERRCODE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION), \
errmsg("could not establish connection"), \
errdetail("%s", msg))); \
} \
freeconn = true; \
} \
} while (0)
#define DBLINK_INIT \
do { \
if (!pconn) \
{ \
pconn = (remoteConn *) MemoryContextAlloc(TopMemoryContext, sizeof(remoteConn)); \
pconn->conn = NULL; \
pconn->openCursorCount = 0; \
pconn->newXactForCursor = FALSE; \
} \
} while (0)
/*
* Create a persistent connection to another database
*/
PG_FUNCTION_INFO_V1(dblink_connect);
Datum
dblink_connect(PG_FUNCTION_ARGS)
{
char *connstr = NULL;
char *connname = NULL;
char *msg;
MemoryContext oldcontext;
PGconn *conn = NULL;
remoteConn *rconn = NULL;
DBLINK_INIT;
if (PG_NARGS() == 2)
{
connstr = GET_STR(PG_GETARG_TEXT_P(1));
connname = GET_STR(PG_GETARG_TEXT_P(0));
}
else if (PG_NARGS() == 1)
connstr = GET_STR(PG_GETARG_TEXT_P(0));
oldcontext = MemoryContextSwitchTo(TopMemoryContext);
if (connname)
rconn = (remoteConn *) palloc(sizeof(remoteConn));
conn = PQconnectdb(connstr);
MemoryContextSwitchTo(oldcontext);
if (PQstatus(conn) == CONNECTION_BAD)
{
msg = pstrdup(PQerrorMessage(conn));
PQfinish(conn);
if (rconn)
pfree(rconn);
ereport(ERROR,
(errcode(ERRCODE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION),
errmsg("could not establish connection"),
errdetail("%s", msg)));
}
if (!superuser())
{
if (!PQconnectionUsedPassword(conn))
{
PQfinish(conn);
if (rconn)
pfree(rconn);
ereport(ERROR,
(errcode(ERRCODE_S_R_E_PROHIBITED_SQL_STATEMENT_ATTEMPTED),
errmsg("password is required"),
errdetail("Non-superuser cannot connect if the server does not request a password."),
errhint("Target server's authentication method must be changed.")));
}
}
if (connname)
{
rconn->conn = conn;
createNewConnection(connname, rconn);
}
else
pconn->conn = conn;
PG_RETURN_TEXT_P(GET_TEXT("OK"));
}
/*
* Clear a persistent connection to another database
*/
PG_FUNCTION_INFO_V1(dblink_disconnect);
Datum
dblink_disconnect(PG_FUNCTION_ARGS)
{
char *conname = NULL;
remoteConn *rconn = NULL;
PGconn *conn = NULL;
DBLINK_INIT;
if (PG_NARGS() == 1)
{
conname = GET_STR(PG_GETARG_TEXT_P(0));
rconn = getConnectionByName(conname);
if (rconn)
conn = rconn->conn;
}
else
conn = pconn->conn;
if (!conn)
DBLINK_CONN_NOT_AVAIL;
PQfinish(conn);
if (rconn)
{
deleteConnection(conname);
pfree(rconn);
}
else
pconn->conn = NULL;
PG_RETURN_TEXT_P(GET_TEXT("OK"));
}
/*
* opens a cursor using a persistent connection
*/
PG_FUNCTION_INFO_V1(dblink_open);
Datum
dblink_open(PG_FUNCTION_ARGS)
{
char *msg;
PGresult *res = NULL;
PGconn *conn = NULL;
char *curname = NULL;
char *sql = NULL;
char *conname = NULL;
StringInfoData buf;
remoteConn *rconn = NULL;
bool fail = true; /* default to backward compatible behavior */
DBLINK_INIT;
initStringInfo(&buf);
if (PG_NARGS() == 2)
{
/* text,text */
curname = GET_STR(PG_GETARG_TEXT_P(0));
sql = GET_STR(PG_GETARG_TEXT_P(1));
rconn = pconn;
}
else if (PG_NARGS() == 3)
{
/* might be text,text,text or text,text,bool */
if (get_fn_expr_argtype(fcinfo->flinfo, 2) == BOOLOID)
{
curname = GET_STR(PG_GETARG_TEXT_P(0));
sql = GET_STR(PG_GETARG_TEXT_P(1));
fail = PG_GETARG_BOOL(2);
rconn = pconn;
}
else
{
conname = GET_STR(PG_GETARG_TEXT_P(0));
curname = GET_STR(PG_GETARG_TEXT_P(1));
sql = GET_STR(PG_GETARG_TEXT_P(2));
rconn = getConnectionByName(conname);
}
}
else if (PG_NARGS() == 4)
{
/* text,text,text,bool */
conname = GET_STR(PG_GETARG_TEXT_P(0));
curname = GET_STR(PG_GETARG_TEXT_P(1));
sql = GET_STR(PG_GETARG_TEXT_P(2));
fail = PG_GETARG_BOOL(3);
rconn = getConnectionByName(conname);
}
if (!rconn || !rconn->conn)
DBLINK_CONN_NOT_AVAIL;
else
conn = rconn->conn;
/* If we are not in a transaction, start one */
if (PQtransactionStatus(conn) == PQTRANS_IDLE)
{
res = PQexec(conn, "BEGIN");
if (PQresultStatus(res) != PGRES_COMMAND_OK)
DBLINK_RES_INTERNALERROR("begin error");
PQclear(res);
rconn->newXactForCursor = TRUE;
/*
* Since transaction state was IDLE, we force cursor count to
* initially be 0. This is needed as a previous ABORT might have wiped
* out our transaction without maintaining the cursor count for us.
*/
rconn->openCursorCount = 0;
}
/* if we started a transaction, increment cursor count */
if (rconn->newXactForCursor)
(rconn->openCursorCount)++;
appendStringInfo(&buf, "DECLARE %s CURSOR FOR %s", curname, sql);
res = PQexec(conn, buf.data);
if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
{
if (fail)
DBLINK_RES_ERROR("sql error");
else
{
DBLINK_RES_ERROR_AS_NOTICE("sql error");
PG_RETURN_TEXT_P(GET_TEXT("ERROR"));
}
}
PQclear(res);
PG_RETURN_TEXT_P(GET_TEXT("OK"));
}
/*
* closes a cursor
*/
PG_FUNCTION_INFO_V1(dblink_close);
Datum
dblink_close(PG_FUNCTION_ARGS)
{
PGconn *conn = NULL;
PGresult *res = NULL;
char *curname = NULL;
char *conname = NULL;
StringInfoData buf;
char *msg;
remoteConn *rconn = NULL;
bool fail = true; /* default to backward compatible behavior */
DBLINK_INIT;
initStringInfo(&buf);
if (PG_NARGS() == 1)
{
/* text */
curname = GET_STR(PG_GETARG_TEXT_P(0));
rconn = pconn;
}
else if (PG_NARGS() == 2)
{
/* might be text,text or text,bool */
if (get_fn_expr_argtype(fcinfo->flinfo, 1) == BOOLOID)
{
curname = GET_STR(PG_GETARG_TEXT_P(0));
fail = PG_GETARG_BOOL(1);
rconn = pconn;
}
else
{
conname = GET_STR(PG_GETARG_TEXT_P(0));
curname = GET_STR(PG_GETARG_TEXT_P(1));
rconn = getConnectionByName(conname);
}
}
if (PG_NARGS() == 3)
{
/* text,text,bool */
conname = GET_STR(PG_GETARG_TEXT_P(0));
curname = GET_STR(PG_GETARG_TEXT_P(1));
fail = PG_GETARG_BOOL(2);
rconn = getConnectionByName(conname);
}
if (!rconn || !rconn->conn)
DBLINK_CONN_NOT_AVAIL;
else
conn = rconn->conn;
appendStringInfo(&buf, "CLOSE %s", curname);
/* close the cursor */
res = PQexec(conn, buf.data);
if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
{
if (fail)
DBLINK_RES_ERROR("sql error");
else
{
DBLINK_RES_ERROR_AS_NOTICE("sql error");
PG_RETURN_TEXT_P(GET_TEXT("ERROR"));
}
}
PQclear(res);
/* if we started a transaction, decrement cursor count */
if (rconn->newXactForCursor)
{
(rconn->openCursorCount)--;
/* if count is zero, commit the transaction */
if (rconn->openCursorCount == 0)
{
rconn->newXactForCursor = FALSE;
res = PQexec(conn, "COMMIT");
if (PQresultStatus(res) != PGRES_COMMAND_OK)
DBLINK_RES_INTERNALERROR("commit error");
PQclear(res);
}
}
PG_RETURN_TEXT_P(GET_TEXT("OK"));
}
/*
* Fetch results from an open cursor
*/
PG_FUNCTION_INFO_V1(dblink_fetch);
Datum
dblink_fetch(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
TupleDesc tupdesc = NULL;
int call_cntr;
int max_calls;
AttInMetadata *attinmeta;
char *msg;
PGresult *res = NULL;
MemoryContext oldcontext;
char *conname = NULL;
remoteConn *rconn = NULL;
DBLINK_INIT;
/* stuff done only on the first call of the function */
if (SRF_IS_FIRSTCALL())
{
PGconn *conn = NULL;
StringInfoData buf;
char *curname = NULL;
int howmany = 0;
bool fail = true; /* default to backward compatible */
if (PG_NARGS() == 4)
{
/* text,text,int,bool */
conname = GET_STR(PG_GETARG_TEXT_P(0));
curname = GET_STR(PG_GETARG_TEXT_P(1));
howmany = PG_GETARG_INT32(2);
fail = PG_GETARG_BOOL(3);
rconn = getConnectionByName(conname);
if (rconn)
conn = rconn->conn;
}
else if (PG_NARGS() == 3)
{
/* text,text,int or text,int,bool */
if (get_fn_expr_argtype(fcinfo->flinfo, 2) == BOOLOID)
{
curname = GET_STR(PG_GETARG_TEXT_P(0));
howmany = PG_GETARG_INT32(1);
fail = PG_GETARG_BOOL(2);
conn = pconn->conn;
}
else
{
conname = GET_STR(PG_GETARG_TEXT_P(0));
curname = GET_STR(PG_GETARG_TEXT_P(1));
howmany = PG_GETARG_INT32(2);
rconn = getConnectionByName(conname);
if (rconn)
conn = rconn->conn;
}
}
else if (PG_NARGS() == 2)
{
/* text,int */
curname = GET_STR(PG_GETARG_TEXT_P(0));
howmany = PG_GETARG_INT32(1);
conn = pconn->conn;
}
if (!conn)
DBLINK_CONN_NOT_AVAIL;
initStringInfo(&buf);
appendStringInfo(&buf, "FETCH %d FROM %s", howmany, curname);
/* create a function context for cross-call persistence */
funcctx = SRF_FIRSTCALL_INIT();
/*
* switch to memory context appropriate for multiple function calls
*/
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
res = PQexec(conn, buf.data);
if (!res ||
(PQresultStatus(res) != PGRES_COMMAND_OK &&
PQresultStatus(res) != PGRES_TUPLES_OK))
{
if (fail)
DBLINK_RES_ERROR("sql error");
else
{
DBLINK_RES_ERROR_AS_NOTICE("sql error");
SRF_RETURN_DONE(funcctx);
}
}
else if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
/* cursor does not exist - closed already or bad name */
PQclear(res);
ereport(ERROR,
(errcode(ERRCODE_INVALID_CURSOR_NAME),
errmsg("cursor \"%s\" does not exist", curname)));
}
funcctx->max_calls = PQntuples(res);
/* got results, keep track of them */
funcctx->user_fctx = res;
/* get a tuple descriptor for our result type */
switch (get_call_result_type(fcinfo, NULL, &tupdesc))
{
case TYPEFUNC_COMPOSITE:
/* success */
break;
case TYPEFUNC_RECORD:
/* failed to determine actual type of RECORD */
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("function returning record called in context "
"that cannot accept type record")));
break;
default:
/* result type isn't composite */
elog(ERROR, "return type must be a row type");
break;
}
/* make sure we have a persistent copy of the tupdesc */
tupdesc = CreateTupleDescCopy(tupdesc);
/* check result and tuple descriptor have the same number of columns */
if (PQnfields(res) != tupdesc->natts)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("remote query result rowtype does not match "
"the specified FROM clause rowtype")));
/* fast track when no results */
if (funcctx->max_calls < 1)
{
if (res)
PQclear(res);
SRF_RETURN_DONE(funcctx);
}
/* store needed metadata for subsequent calls */
attinmeta = TupleDescGetAttInMetadata(tupdesc);
funcctx->attinmeta = attinmeta;
MemoryContextSwitchTo(oldcontext);
}
/* stuff done on every call of the function */
funcctx = SRF_PERCALL_SETUP();
/*
* initialize per-call variables
*/
call_cntr = funcctx->call_cntr;
max_calls = funcctx->max_calls;
res = (PGresult *) funcctx->user_fctx;
attinmeta = funcctx->attinmeta;
tupdesc = attinmeta->tupdesc;
if (call_cntr < max_calls) /* do when there is more left to send */
{
char **values;
HeapTuple tuple;
Datum result;
int i;
int nfields = PQnfields(res);
values = (char **) palloc(nfields * sizeof(char *));
for (i = 0; i < nfields; i++)
{
if (PQgetisnull(res, call_cntr, i) == 0)
values[i] = PQgetvalue(res, call_cntr, i);
else
values[i] = NULL;
}
/* build the tuple */
tuple = BuildTupleFromCStrings(attinmeta, values);
/* make the tuple into a datum */
result = HeapTupleGetDatum(tuple);
SRF_RETURN_NEXT(funcctx, result);
}
else
{
/* do when there is no more left */
PQclear(res);
SRF_RETURN_DONE(funcctx);
}
}
/*
* Note: this is the new preferred version of dblink
*/
PG_FUNCTION_INFO_V1(dblink_record);
Datum
dblink_record(PG_FUNCTION_ARGS)
{
return dblink_record_internal(fcinfo, false, false);
}
PG_FUNCTION_INFO_V1(dblink_send_query);
Datum
dblink_send_query(PG_FUNCTION_ARGS)
{
return dblink_record_internal(fcinfo, true, false);
}
PG_FUNCTION_INFO_V1(dblink_get_result);
Datum
dblink_get_result(PG_FUNCTION_ARGS)
{
return dblink_record_internal(fcinfo, true, true);
}
static Datum
dblink_record_internal(FunctionCallInfo fcinfo, bool is_async, bool do_get)
{
FuncCallContext *funcctx;
TupleDesc tupdesc = NULL;
int call_cntr;
int max_calls;
AttInMetadata *attinmeta;
char *msg;
PGresult *res = NULL;
bool is_sql_cmd = false;
char *sql_cmd_status = NULL;
MemoryContext oldcontext;
bool freeconn = false;
DBLINK_INIT;
/* stuff done only on the first call of the function */
if (SRF_IS_FIRSTCALL())
{
PGconn *conn = NULL;
char *connstr = NULL;
char *sql = NULL;
char *conname = NULL;
remoteConn *rconn = NULL;
bool fail = true; /* default to backward compatible */
/* create a function context for cross-call persistence */
funcctx = SRF_FIRSTCALL_INIT();
/*
* switch to memory context appropriate for multiple function calls
*/
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
if (!is_async)
{
if (PG_NARGS() == 3)
{
/* text,text,bool */
DBLINK_GET_CONN;
sql = GET_STR(PG_GETARG_TEXT_P(1));
fail = PG_GETARG_BOOL(2);
}
else if (PG_NARGS() == 2)
{
/* text,text or text,bool */
if (get_fn_expr_argtype(fcinfo->flinfo, 1) == BOOLOID)
{
conn = pconn->conn;
sql = GET_STR(PG_GETARG_TEXT_P(0));
fail = PG_GETARG_BOOL(1);
}
else
{
DBLINK_GET_CONN;
sql = GET_STR(PG_GETARG_TEXT_P(1));
}
}
else if (PG_NARGS() == 1)
{
/* text */
conn = pconn->conn;
sql = GET_STR(PG_GETARG_TEXT_P(0));
}
else
/* shouldn't happen */
elog(ERROR, "wrong number of arguments");
}
else if (is_async && do_get)
{
/* get async result */
if (PG_NARGS() == 2)
{
/* text,bool */
DBLINK_GET_CONN;
fail = PG_GETARG_BOOL(2);
}
else if (PG_NARGS() == 1)
{
/* text */
DBLINK_GET_CONN;
}
else
/* shouldn't happen */
elog(ERROR, "wrong number of arguments");
}
else
{
/* send async query */
if (PG_NARGS() == 2)
{
DBLINK_GET_CONN;
sql = GET_STR(PG_GETARG_TEXT_P(1));
}
else
/* shouldn't happen */
elog(ERROR, "wrong number of arguments");
}
if (!conn)
DBLINK_CONN_NOT_AVAIL;
if (!is_async || (is_async && do_get))
{
/* synchronous query, or async result retrieval */
if (!is_async)
res = PQexec(conn, sql);
else
{
res = PQgetResult(conn);
/* NULL means we're all done with the async results */
if (!res)
SRF_RETURN_DONE(funcctx);
}
if (!res ||
(PQresultStatus(res) != PGRES_COMMAND_OK &&
PQresultStatus(res) != PGRES_TUPLES_OK))
{
if (fail)
DBLINK_RES_ERROR("sql error");
else
{
DBLINK_RES_ERROR_AS_NOTICE("sql error");
if (freeconn)
PQfinish(conn);
SRF_RETURN_DONE(funcctx);
}
}
if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
is_sql_cmd = true;
/* need a tuple descriptor representing one TEXT column */
tupdesc = CreateTemplateTupleDesc(1, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "status",
TEXTOID, -1, 0);
/*
* and save a copy of the command status string to return as
* our result tuple
*/
sql_cmd_status = PQcmdStatus(res);
funcctx->max_calls = 1;
}
else
funcctx->max_calls = PQntuples(res);
/* got results, keep track of them */
funcctx->user_fctx = res;
/* if needed, close the connection to the database and cleanup */
if (freeconn)
PQfinish(conn);
if (!is_sql_cmd)
{
/* get a tuple descriptor for our result type */
switch (get_call_result_type(fcinfo, NULL, &tupdesc))
{
case TYPEFUNC_COMPOSITE:
/* success */
break;
case TYPEFUNC_RECORD:
/* failed to determine actual type of RECORD */
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("function returning record called in context "
"that cannot accept type record")));
break;
default:
/* result type isn't composite */
elog(ERROR, "return type must be a row type");
break;
}
/* make sure we have a persistent copy of the tupdesc */
tupdesc = CreateTupleDescCopy(tupdesc);
}
/*
* check result and tuple descriptor have the same number of
* columns
*/
if (PQnfields(res) != tupdesc->natts)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("remote query result rowtype does not match "
"the specified FROM clause rowtype")));
/* fast track when no results */
if (funcctx->max_calls < 1)
{
if (res)
PQclear(res);
SRF_RETURN_DONE(funcctx);
}
/* store needed metadata for subsequent calls */
attinmeta = TupleDescGetAttInMetadata(tupdesc);
funcctx->attinmeta = attinmeta;
MemoryContextSwitchTo(oldcontext);
}
else
{
/* async query send */
MemoryContextSwitchTo(oldcontext);
PG_RETURN_INT32(PQsendQuery(conn, sql));
}
}
if (is_async && !do_get)
{
/* async query send -- should not happen */
elog(ERROR, "async query send called more than once");
}
/* stuff done on every call of the function */
funcctx = SRF_PERCALL_SETUP();
/*
* initialize per-call variables
*/
call_cntr = funcctx->call_cntr;
max_calls = funcctx->max_calls;
res = (PGresult *) funcctx->user_fctx;
attinmeta = funcctx->attinmeta;
tupdesc = attinmeta->tupdesc;
if (call_cntr < max_calls) /* do when there is more left to send */
{
char **values;
HeapTuple tuple;
Datum result;
if (!is_sql_cmd)
{
int i;
int nfields = PQnfields(res);
values = (char **) palloc(nfields * sizeof(char *));
for (i = 0; i < nfields; i++)
{
if (PQgetisnull(res, call_cntr, i) == 0)
values[i] = PQgetvalue(res, call_cntr, i);
else
values[i] = NULL;
}
}
else
{
values = (char **) palloc(1 * sizeof(char *));
values[0] = sql_cmd_status;
}
/* build the tuple */
tuple = BuildTupleFromCStrings(attinmeta, values);
/* make the tuple into a datum */
result = HeapTupleGetDatum(tuple);
SRF_RETURN_NEXT(funcctx, result);
}
else
{
/* do when there is no more left */
PQclear(res);
SRF_RETURN_DONE(funcctx);
}
}
/*
* List all open dblink connections by name.
* Returns an array of all connection names.
* Takes no params
*/
PG_FUNCTION_INFO_V1(dblink_get_connections);
Datum
dblink_get_connections(PG_FUNCTION_ARGS)
{
HASH_SEQ_STATUS status;
remoteConnHashEnt *hentry;
ArrayBuildState *astate = NULL;
if (remoteConnHash)
{
hash_seq_init(&status, remoteConnHash);
while ((hentry = (remoteConnHashEnt *) hash_seq_search(&status)) != NULL)
{
/* stash away current value */
astate = accumArrayResult(astate,
PointerGetDatum(GET_TEXT(hentry->name)),
false, TEXTOID, CurrentMemoryContext);
}
}
if (astate)
PG_RETURN_ARRAYTYPE_P(makeArrayResult(astate,
CurrentMemoryContext));
else
PG_RETURN_NULL();
}
/*
* Checks if a given remote connection is busy
*
* Returns 1 if the connection is busy, 0 otherwise
* Params:
* text connection_name - name of the connection to check
*
*/
PG_FUNCTION_INFO_V1(dblink_is_busy);
Datum
dblink_is_busy(PG_FUNCTION_ARGS)
{
char *msg;
PGconn *conn = NULL;
char *conname = NULL;
char *connstr = NULL;
remoteConn *rconn = NULL;
bool freeconn = false;
DBLINK_INIT;
DBLINK_GET_CONN;
if (!conn)
DBLINK_CONN_NOT_AVAIL;
PQconsumeInput(conn);
PG_RETURN_INT32(PQisBusy(conn));
}
/*
* Cancels a running request on a connection
*
* Returns text:
* "OK" if the cancel request has been sent correctly,
* an error message otherwise
*
* Params:
* text connection_name - name of the connection to check
*
*/
PG_FUNCTION_INFO_V1(dblink_cancel_query);
Datum
dblink_cancel_query(PG_FUNCTION_ARGS)
{
char *msg;
int res = 0;
PGconn *conn = NULL;
char *conname = NULL;
char *connstr = NULL;
remoteConn *rconn = NULL;
bool freeconn = false;
PGcancel *cancel;
char errbuf[256];
DBLINK_INIT;
DBLINK_GET_CONN;
if (!conn)
DBLINK_CONN_NOT_AVAIL;
cancel = PQgetCancel(conn);
res = PQcancel(cancel, errbuf, 256);
PQfreeCancel(cancel);
if (res == 0)
PG_RETURN_TEXT_P(GET_TEXT("OK"));
else
PG_RETURN_TEXT_P(GET_TEXT(errbuf));
}
/*
* Get error message from a connection
*
* Returns text:
* "OK" if no error, an error message otherwise
*
* Params:
* text connection_name - name of the connection to check
*
*/
PG_FUNCTION_INFO_V1(dblink_error_message);
Datum
dblink_error_message(PG_FUNCTION_ARGS)
{
char *msg;
PGconn *conn = NULL;
char *conname = NULL;
char *connstr = NULL;
remoteConn *rconn = NULL;
bool freeconn = false;
DBLINK_INIT;
DBLINK_GET_CONN;
if (!conn)
DBLINK_CONN_NOT_AVAIL;
msg = PQerrorMessage(conn);
if (!msg)
PG_RETURN_TEXT_P(GET_TEXT("OK"));
else
PG_RETURN_TEXT_P(GET_TEXT(msg));
}
/*
* Execute an SQL non-SELECT command
*/
PG_FUNCTION_INFO_V1(dblink_exec);
Datum
dblink_exec(PG_FUNCTION_ARGS)
{
char *msg;
PGresult *res = NULL;
text *sql_cmd_status = NULL;
TupleDesc tupdesc = NULL;
PGconn *conn = NULL;
char *connstr = NULL;
char *sql = NULL;
char *conname = NULL;
remoteConn *rconn = NULL;
bool freeconn = false;
bool fail = true; /* default to backward compatible behavior */
DBLINK_INIT;
if (PG_NARGS() == 3)
{
/* must be text,text,bool */
DBLINK_GET_CONN;
sql = GET_STR(PG_GETARG_TEXT_P(1));
fail = PG_GETARG_BOOL(2);
}
else if (PG_NARGS() == 2)
{
/* might be text,text or text,bool */
if (get_fn_expr_argtype(fcinfo->flinfo, 1) == BOOLOID)
{
conn = pconn->conn;
sql = GET_STR(PG_GETARG_TEXT_P(0));
fail = PG_GETARG_BOOL(1);
}
else
{
DBLINK_GET_CONN;
sql = GET_STR(PG_GETARG_TEXT_P(1));
}
}
else if (PG_NARGS() == 1)
{
/* must be single text argument */
conn = pconn->conn;
sql = GET_STR(PG_GETARG_TEXT_P(0));
}
else
/* shouldn't happen */
elog(ERROR, "wrong number of arguments");
if (!conn)
DBLINK_CONN_NOT_AVAIL;
res = PQexec(conn, sql);
if (!res ||
(PQresultStatus(res) != PGRES_COMMAND_OK &&
PQresultStatus(res) != PGRES_TUPLES_OK))
{
if (fail)
DBLINK_RES_ERROR("sql error");
else
DBLINK_RES_ERROR_AS_NOTICE("sql error");
/* need a tuple descriptor representing one TEXT column */
tupdesc = CreateTemplateTupleDesc(1, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "status",
TEXTOID, -1, 0);
/*
* and save a copy of the command status string to return as our
* result tuple
*/
sql_cmd_status = GET_TEXT("ERROR");
}
else if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
/* need a tuple descriptor representing one TEXT column */
tupdesc = CreateTemplateTupleDesc(1, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "status",
TEXTOID, -1, 0);
/*
* and save a copy of the command status string to return as our
* result tuple
*/
sql_cmd_status = GET_TEXT(PQcmdStatus(res));
PQclear(res);
}
else
{
PQclear(res);
ereport(ERROR,
(errcode(ERRCODE_S_R_E_PROHIBITED_SQL_STATEMENT_ATTEMPTED),
errmsg("statement returning results not allowed")));
}
/* if needed, close the connection to the database and cleanup */
if (freeconn)
PQfinish(conn);
PG_RETURN_TEXT_P(sql_cmd_status);
}
/*
* dblink_get_pkey
*
* Return list of primary key fields for the supplied relation,
* or NULL if none exists.
*/
PG_FUNCTION_INFO_V1(dblink_get_pkey);
Datum
dblink_get_pkey(PG_FUNCTION_ARGS)
{
int16 numatts;
Oid relid;
char **results;
FuncCallContext *funcctx;
int32 call_cntr;
int32 max_calls;
AttInMetadata *attinmeta;
MemoryContext oldcontext;
/* stuff done only on the first call of the function */
if (SRF_IS_FIRSTCALL())
{
TupleDesc tupdesc = NULL;
/* create a function context for cross-call persistence */
funcctx = SRF_FIRSTCALL_INIT();
/*
* switch to memory context appropriate for multiple function calls
*/
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
/* convert relname to rel Oid */
relid = get_relid_from_relname(PG_GETARG_TEXT_P(0));
if (!OidIsValid(relid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("relation \"%s\" does not exist",
GET_STR(PG_GETARG_TEXT_P(0)))));
/*
* need a tuple descriptor representing one INT and one TEXT column
*/
tupdesc = CreateTemplateTupleDesc(2, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "position",
INT4OID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 2, "colname",
TEXTOID, -1, 0);
/*
* Generate attribute metadata needed later to produce tuples from raw
* C strings
*/
attinmeta = TupleDescGetAttInMetadata(tupdesc);
funcctx->attinmeta = attinmeta;
/* get an array of attnums */
results = get_pkey_attnames(relid, &numatts);
if ((results != NULL) && (numatts > 0))
{
funcctx->max_calls = numatts;
/* got results, keep track of them */
funcctx->user_fctx = results;
}
else
/* fast track when no results */
SRF_RETURN_DONE(funcctx);
MemoryContextSwitchTo(oldcontext);
}
/* stuff done on every call of the function */
funcctx = SRF_PERCALL_SETUP();
/*
* initialize per-call variables
*/
call_cntr = funcctx->call_cntr;
max_calls = funcctx->max_calls;
results = (char **) funcctx->user_fctx;
attinmeta = funcctx->attinmeta;
if (call_cntr < max_calls) /* do when there is more left to send */
{
char **values;
HeapTuple tuple;
Datum result;
values = (char **) palloc(2 * sizeof(char *));
values[0] = (char *) palloc(12); /* sign, 10 digits, '\0' */
sprintf(values[0], "%d", call_cntr + 1);
values[1] = results[call_cntr];
/* build the tuple */
tuple = BuildTupleFromCStrings(attinmeta, values);
/* make the tuple into a datum */
result = HeapTupleGetDatum(tuple);
SRF_RETURN_NEXT(funcctx, result);
}
else
{
/* do when there is no more left */
SRF_RETURN_DONE(funcctx);
}
}
/*
* dblink_build_sql_insert
*
* Used to generate an SQL insert statement
* based on an existing tuple in a local relation.
* This is useful for selectively replicating data
* to another server via dblink.
*
* API:
* <relname> - name of local table of interest
* <pkattnums> - an int2vector of attnums which will be used
* to identify the local tuple of interest
* <pknumatts> - number of attnums in pkattnums
* <src_pkattvals_arry> - text array of key values which will be used
* to identify the local tuple of interest
* <tgt_pkattvals_arry> - text array of key values which will be used
* to build the string for execution remotely. These are substituted
* for their counterparts in src_pkattvals_arry
*/
PG_FUNCTION_INFO_V1(dblink_build_sql_insert);
Datum
dblink_build_sql_insert(PG_FUNCTION_ARGS)
{
text *relname_text = PG_GETARG_TEXT_P(0);
int2vector *pkattnums = (int2vector *) PG_GETARG_POINTER(1);
int32 pknumatts_tmp = PG_GETARG_INT32(2);
ArrayType *src_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
ArrayType *tgt_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(4);
Oid relid;
int16 pknumatts = 0;
char **src_pkattvals;
char **tgt_pkattvals;
int src_nitems;
int tgt_nitems;
char *sql;
/*
* Convert relname to rel OID.
*/
relid = get_relid_from_relname(relname_text);
if (!OidIsValid(relid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("relation \"%s\" does not exist",
GET_STR(relname_text))));
/*
* There should be at least one key attribute
*/
if (pknumatts_tmp <= 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("number of key attributes must be > 0")));
if (pknumatts_tmp <= SHRT_MAX)
pknumatts = pknumatts_tmp;
else
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("input for number of primary key " \
"attributes too large")));
/*
* Source array is made up of key values that will be used to locate the
* tuple of interest from the local system.
*/
src_pkattvals = get_text_array_contents(src_pkattvals_arry, &src_nitems);
/*
* There should be one source array key value for each key attnum
*/
if (src_nitems != pknumatts)
ereport(ERROR,
(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
errmsg("source key array length must match number of key " \
"attributes")));
/*
* Target array is made up of key values that will be used to build the
* SQL string for use on the remote system.
*/
tgt_pkattvals = get_text_array_contents(tgt_pkattvals_arry, &tgt_nitems);
/*
* There should be one target array key value for each key attnum
*/
if (tgt_nitems != pknumatts)
ereport(ERROR,
(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
errmsg("target key array length must match number of key " \
"attributes")));
/*
* Prep work is finally done. Go get the SQL string.
*/
sql = get_sql_insert(relid, pkattnums, pknumatts, src_pkattvals, tgt_pkattvals);
/*
* And send it
*/
PG_RETURN_TEXT_P(GET_TEXT(sql));
}
/*
* dblink_build_sql_delete
*
* Used to generate an SQL delete statement.
* This is useful for selectively replicating a
* delete to another server via dblink.
*
* API:
* <relname> - name of remote table of interest
* <pkattnums> - an int2vector of attnums which will be used
* to identify the remote tuple of interest
* <pknumatts> - number of attnums in pkattnums
* <tgt_pkattvals_arry> - text array of key values which will be used
* to build the string for execution remotely.
*/
PG_FUNCTION_INFO_V1(dblink_build_sql_delete);
Datum
dblink_build_sql_delete(PG_FUNCTION_ARGS)
{
text *relname_text = PG_GETARG_TEXT_P(0);
int2vector *pkattnums = (int2vector *) PG_GETARG_POINTER(1);
int32 pknumatts_tmp = PG_GETARG_INT32(2);
ArrayType *tgt_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
Oid relid;
int16 pknumatts = 0;
char **tgt_pkattvals;
int tgt_nitems;
char *sql;
/*
* Convert relname to rel OID.
*/
relid = get_relid_from_relname(relname_text);
if (!OidIsValid(relid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("relation \"%s\" does not exist",
GET_STR(relname_text))));
/*
* There should be at least one key attribute
*/
if (pknumatts_tmp <= 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("number of key attributes must be > 0")));
if (pknumatts_tmp <= SHRT_MAX)
pknumatts = pknumatts_tmp;
else
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("input for number of primary key " \
"attributes too large")));
/*
* Target array is made up of key values that will be used to build the
* SQL string for use on the remote system.
*/
tgt_pkattvals = get_text_array_contents(tgt_pkattvals_arry, &tgt_nitems);
/*
* There should be one target array key value for each key attnum
*/
if (tgt_nitems != pknumatts)
ereport(ERROR,
(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
errmsg("target key array length must match number of key " \
"attributes")));
/*
* Prep work is finally done. Go get the SQL string.
*/
sql = get_sql_delete(relid, pkattnums, pknumatts, tgt_pkattvals);
/*
* And send it
*/
PG_RETURN_TEXT_P(GET_TEXT(sql));
}
/*
* dblink_build_sql_update
*
* Used to generate an SQL update statement
* based on an existing tuple in a local relation.
* This is useful for selectively replicating data
* to another server via dblink.
*
* API:
* <relname> - name of local table of interest
* <pkattnums> - an int2vector of attnums which will be used
* to identify the local tuple of interest
* <pknumatts> - number of attnums in pkattnums
* <src_pkattvals_arry> - text array of key values which will be used
* to identify the local tuple of interest
* <tgt_pkattvals_arry> - text array of key values which will be used
* to build the string for execution remotely. These are substituted
* for their counterparts in src_pkattvals_arry
*/
PG_FUNCTION_INFO_V1(dblink_build_sql_update);
Datum
dblink_build_sql_update(PG_FUNCTION_ARGS)
{
text *relname_text = PG_GETARG_TEXT_P(0);
int2vector *pkattnums = (int2vector *) PG_GETARG_POINTER(1);
int32 pknumatts_tmp = PG_GETARG_INT32(2);
ArrayType *src_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
ArrayType *tgt_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(4);
Oid relid;
int16 pknumatts = 0;
char **src_pkattvals;
char **tgt_pkattvals;
int src_nitems;
int tgt_nitems;
char *sql;
/*
* Convert relname to rel OID.
*/
relid = get_relid_from_relname(relname_text);
if (!OidIsValid(relid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("relation \"%s\" does not exist",
GET_STR(relname_text))));
/*
* There should be one source array key values for each key attnum
*/
if (pknumatts_tmp <= 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("number of key attributes must be > 0")));
if (pknumatts_tmp <= SHRT_MAX)
pknumatts = pknumatts_tmp;
else
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("input for number of primary key " \
"attributes too large")));
/*
* Source array is made up of key values that will be used to locate the
* tuple of interest from the local system.
*/
src_pkattvals = get_text_array_contents(src_pkattvals_arry, &src_nitems);
/*
* There should be one source array key value for each key attnum
*/
if (src_nitems != pknumatts)
ereport(ERROR,
(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
errmsg("source key array length must match number of key " \
"attributes")));
/*
* Target array is made up of key values that will be used to build the
* SQL string for use on the remote system.
*/
tgt_pkattvals = get_text_array_contents(tgt_pkattvals_arry, &tgt_nitems);
/*
* There should be one target array key value for each key attnum
*/
if (tgt_nitems != pknumatts)
ereport(ERROR,
(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
errmsg("target key array length must match number of key " \
"attributes")));
/*
* Prep work is finally done. Go get the SQL string.
*/
sql = get_sql_update(relid, pkattnums, pknumatts, src_pkattvals, tgt_pkattvals);
/*
* And send it
*/
PG_RETURN_TEXT_P(GET_TEXT(sql));
}
/*
* dblink_current_query
* return the current query string
* to allow its use in (among other things)
* rewrite rules
*/
PG_FUNCTION_INFO_V1(dblink_current_query);
Datum
dblink_current_query(PG_FUNCTION_ARGS)
{
if (debug_query_string)
PG_RETURN_TEXT_P(GET_TEXT(debug_query_string));
else
PG_RETURN_NULL();
}
/*************************************************************
* internal functions
*/
/*
* get_pkey_attnames
*
* Get the primary key attnames for the given relation.
* Return NULL, and set numatts = 0, if no primary key exists.
*/
static char **
get_pkey_attnames(Oid relid, int16 *numatts)
{
Relation indexRelation;
ScanKeyData entry;
HeapScanDesc scan;
HeapTuple indexTuple;
int i;
char **result = NULL;
Relation rel;
TupleDesc tupdesc;
/* open relation using relid, get tupdesc */
rel = relation_open(relid, AccessShareLock);
tupdesc = rel->rd_att;
/* initialize numatts to 0 in case no primary key exists */
*numatts = 0;
/* use relid to get all related indexes */
indexRelation = heap_open(IndexRelationId, AccessShareLock);
ScanKeyInit(&entry,
Anum_pg_index_indrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(relid));
scan = heap_beginscan(indexRelation, SnapshotNow, 1, &entry);
while ((indexTuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
Form_pg_index index = (Form_pg_index) GETSTRUCT(indexTuple);
/* we're only interested if it is the primary key */
if (index->indisprimary == TRUE)
{
*numatts = index->indnatts;
if (*numatts > 0)
{
result = (char **) palloc(*numatts * sizeof(char *));
for (i = 0; i < *numatts; i++)
result[i] = SPI_fname(tupdesc, index->indkey.values[i]);
}
break;
}
}
heap_endscan(scan);
heap_close(indexRelation, AccessShareLock);
relation_close(rel, AccessShareLock);
return result;
}
/*
* Deconstruct a text[] into C-strings (note any NULL elements will be
* returned as NULL pointers)
*/
static char **
get_text_array_contents(ArrayType *array, int *numitems)
{
int ndim = ARR_NDIM(array);
int *dims = ARR_DIMS(array);
int nitems;
int16 typlen;
bool typbyval;
char typalign;
char **values;
char *ptr;
bits8 *bitmap;
int bitmask;
int i;
Assert(ARR_ELEMTYPE(array) == TEXTOID);
*numitems = nitems = ArrayGetNItems(ndim, dims);
get_typlenbyvalalign(ARR_ELEMTYPE(array),
&typlen, &typbyval, &typalign);
values = (char **) palloc(nitems * sizeof(char *));
ptr = ARR_DATA_PTR(array);
bitmap = ARR_NULLBITMAP(array);
bitmask = 1;
for (i = 0; i < nitems; i++)
{
if (bitmap && (*bitmap & bitmask) == 0)
{
values[i] = NULL;
}
else
{
values[i] = DatumGetCString(DirectFunctionCall1(textout,
PointerGetDatum(ptr)));
ptr = att_addlength_pointer(ptr, typlen, ptr);
ptr = (char *) att_align_nominal(ptr, typalign);
}
/* advance bitmap pointer if any */
if (bitmap)
{
bitmask <<= 1;
if (bitmask == 0x100)
{
bitmap++;
bitmask = 1;
}
}
}
return values;
}
static char *
get_sql_insert(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals, char **tgt_pkattvals)
{
Relation rel;
char *relname;
HeapTuple tuple;
TupleDesc tupdesc;
int natts;
StringInfoData buf;
char *val;
int16 key;
int i;
bool needComma;
initStringInfo(&buf);
/* get relation name including any needed schema prefix and quoting */
relname = generate_relation_name(relid);
/*
* Open relation using relid
*/
rel = relation_open(relid, AccessShareLock);
tupdesc = rel->rd_att;
natts = tupdesc->natts;
tuple = get_tuple_of_interest(relid, pkattnums, pknumatts, src_pkattvals);
if (!tuple)
ereport(ERROR,
(errcode(ERRCODE_CARDINALITY_VIOLATION),
errmsg("source row not found")));
appendStringInfo(&buf, "INSERT INTO %s(", relname);
needComma = false;
for (i = 0; i < natts; i++)
{
if (tupdesc->attrs[i]->attisdropped)
continue;
if (needComma)
appendStringInfo(&buf, ",");
appendStringInfoString(&buf,
quote_ident_cstr(NameStr(tupdesc->attrs[i]->attname)));
needComma = true;
}
appendStringInfo(&buf, ") VALUES(");
/*
* remember attvals are 1 based
*/
needComma = false;
for (i = 0; i < natts; i++)
{
if (tupdesc->attrs[i]->attisdropped)
continue;
if (needComma)
appendStringInfo(&buf, ",");
if (tgt_pkattvals != NULL)
key = get_attnum_pk_pos(pkattnums, pknumatts, i + 1);
else
key = -1;
if (key > -1)
val = tgt_pkattvals[key] ? pstrdup(tgt_pkattvals[key]) : NULL;
else
val = SPI_getvalue(tuple, tupdesc, i + 1);
if (val != NULL)
{
appendStringInfoString(&buf, quote_literal_cstr(val));
pfree(val);
}
else
appendStringInfo(&buf, "NULL");
needComma = true;
}
appendStringInfo(&buf, ")");
relation_close(rel, AccessShareLock);
return (buf.data);
}
static char *
get_sql_delete(Oid relid, int2vector *pkattnums, int16 pknumatts, char **tgt_pkattvals)
{
Relation rel;
char *relname;
TupleDesc tupdesc;
int natts;
StringInfoData buf;
int i;
initStringInfo(&buf);
/* get relation name including any needed schema prefix and quoting */
relname = generate_relation_name(relid);
/*
* Open relation using relid
*/
rel = relation_open(relid, AccessShareLock);
tupdesc = rel->rd_att;
natts = tupdesc->natts;
appendStringInfo(&buf, "DELETE FROM %s WHERE ", relname);
for (i = 0; i < pknumatts; i++)
{
int16 pkattnum = pkattnums->values[i];
if (i > 0)
appendStringInfo(&buf, " AND ");
appendStringInfoString(&buf,
quote_ident_cstr(NameStr(tupdesc->attrs[pkattnum - 1]->attname)));
if (tgt_pkattvals == NULL)
/* internal error */
elog(ERROR, "target key array must not be NULL");
if (tgt_pkattvals[i] != NULL)
appendStringInfo(&buf, " = %s",
quote_literal_cstr(tgt_pkattvals[i]));
else
appendStringInfo(&buf, " IS NULL");
}
relation_close(rel, AccessShareLock);
return (buf.data);
}
static char *
get_sql_update(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals, char **tgt_pkattvals)
{
Relation rel;
char *relname;
HeapTuple tuple;
TupleDesc tupdesc;
int natts;
StringInfoData buf;
char *val;
int16 key;
int i;
bool needComma;
initStringInfo(&buf);
/* get relation name including any needed schema prefix and quoting */
relname = generate_relation_name(relid);
/*
* Open relation using relid
*/
rel = relation_open(relid, AccessShareLock);
tupdesc = rel->rd_att;
natts = tupdesc->natts;
tuple = get_tuple_of_interest(relid, pkattnums, pknumatts, src_pkattvals);
if (!tuple)
ereport(ERROR,
(errcode(ERRCODE_CARDINALITY_VIOLATION),
errmsg("source row not found")));
appendStringInfo(&buf, "UPDATE %s SET ", relname);
needComma = false;
for (i = 0; i < natts; i++)
{
if (tupdesc->attrs[i]->attisdropped)
continue;
if (needComma)
appendStringInfo(&buf, ", ");
appendStringInfo(&buf, "%s = ",
quote_ident_cstr(NameStr(tupdesc->attrs[i]->attname)));
if (tgt_pkattvals != NULL)
key = get_attnum_pk_pos(pkattnums, pknumatts, i + 1);
else
key = -1;
if (key > -1)
val = tgt_pkattvals[key] ? pstrdup(tgt_pkattvals[key]) : NULL;
else
val = SPI_getvalue(tuple, tupdesc, i + 1);
if (val != NULL)
{
appendStringInfoString(&buf, quote_literal_cstr(val));
pfree(val);
}
else
appendStringInfoString(&buf, "NULL");
needComma = true;
}
appendStringInfo(&buf, " WHERE ");
for (i = 0; i < pknumatts; i++)
{
int16 pkattnum = pkattnums->values[i];
if (i > 0)
appendStringInfo(&buf, " AND ");
appendStringInfo(&buf, "%s",
quote_ident_cstr(NameStr(tupdesc->attrs[pkattnum - 1]->attname)));
if (tgt_pkattvals != NULL)
val = tgt_pkattvals[i] ? pstrdup(tgt_pkattvals[i]) : NULL;
else
val = SPI_getvalue(tuple, tupdesc, pkattnum);
if (val != NULL)
{
appendStringInfo(&buf, " = %s", quote_literal_cstr(val));
pfree(val);
}
else
appendStringInfo(&buf, " IS NULL");
}
relation_close(rel, AccessShareLock);
return (buf.data);
}
/*
* Return a properly quoted literal value.
* Uses quote_literal in quote.c
*/
static char *
quote_literal_cstr(char *rawstr)
{
text *rawstr_text;
text *result_text;
char *result;
rawstr_text = DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(rawstr)));
result_text = DatumGetTextP(DirectFunctionCall1(quote_literal, PointerGetDatum(rawstr_text)));
result = DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(result_text)));
return result;
}
/*
* Return a properly quoted identifier.
* Uses quote_ident in quote.c
*/
static char *
quote_ident_cstr(char *rawstr)
{
text *rawstr_text;
text *result_text;
char *result;
rawstr_text = DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(rawstr)));
result_text = DatumGetTextP(DirectFunctionCall1(quote_ident, PointerGetDatum(rawstr_text)));
result = DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(result_text)));
return result;
}
static int16
get_attnum_pk_pos(int2vector *pkattnums, int16 pknumatts, int16 key)
{
int i;
/*
* Not likely a long list anyway, so just scan for the value
*/
for (i = 0; i < pknumatts; i++)
if (key == pkattnums->values[i])
return i;
return -1;
}
static HeapTuple
get_tuple_of_interest(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals)
{
Relation rel;
char *relname;
TupleDesc tupdesc;
StringInfoData buf;
int ret;
HeapTuple tuple;
int i;
initStringInfo(&buf);
/* get relation name including any needed schema prefix and quoting */
relname = generate_relation_name(relid);
/*
* Open relation using relid
*/
rel = relation_open(relid, AccessShareLock);
tupdesc = CreateTupleDescCopy(rel->rd_att);
relation_close(rel, AccessShareLock);
/*
* Connect to SPI manager
*/
if ((ret = SPI_connect()) < 0)
/* internal error */
elog(ERROR, "SPI connect failure - returned %d", ret);
/*
* Build sql statement to look up tuple of interest Use src_pkattvals as
* the criteria.
*/
appendStringInfo(&buf, "SELECT * FROM %s WHERE ", relname);
for (i = 0; i < pknumatts; i++)
{
int16 pkattnum = pkattnums->values[i];
if (i > 0)
appendStringInfo(&buf, " AND ");
appendStringInfoString(&buf,
quote_ident_cstr(NameStr(tupdesc->attrs[pkattnum - 1]->attname)));
if (src_pkattvals[i] != NULL)
appendStringInfo(&buf, " = %s",
quote_literal_cstr(src_pkattvals[i]));
else
appendStringInfo(&buf, " IS NULL");
}
/*
* Retrieve the desired tuple
*/
ret = SPI_exec(buf.data, 0);
pfree(buf.data);
/*
* Only allow one qualifying tuple
*/
if ((ret == SPI_OK_SELECT) && (SPI_processed > 1))
ereport(ERROR,
(errcode(ERRCODE_CARDINALITY_VIOLATION),
errmsg("source criteria matched more than one record")));
else if (ret == SPI_OK_SELECT && SPI_processed == 1)
{
SPITupleTable *tuptable = SPI_tuptable;
tuple = SPI_copytuple(tuptable->vals[0]);
SPI_finish();
return tuple;
}
else
{
/*
* no qualifying tuples
*/
SPI_finish();
return NULL;
}
/*
* never reached, but keep compiler quiet
*/
return NULL;
}
static Oid
get_relid_from_relname(text *relname_text)
{
RangeVar *relvar;
Relation rel;
Oid relid;
relvar = makeRangeVarFromNameList(textToQualifiedNameList(relname_text));
rel = heap_openrv(relvar, AccessShareLock);
relid = RelationGetRelid(rel);
relation_close(rel, AccessShareLock);
return relid;
}
/*
* generate_relation_name - copied from ruleutils.c
* Compute the name to display for a relation specified by OID
*
* The result includes all necessary quoting and schema-prefixing.
*/
static char *
generate_relation_name(Oid relid)
{
HeapTuple tp;
Form_pg_class reltup;
char *nspname;
char *result;
tp = SearchSysCache(RELOID,
ObjectIdGetDatum(relid),
0, 0, 0);
if (!HeapTupleIsValid(tp))
elog(ERROR, "cache lookup failed for relation %u", relid);
reltup = (Form_pg_class) GETSTRUCT(tp);
/* Qualify the name if not visible in search path */
if (RelationIsVisible(relid))
nspname = NULL;
else
nspname = get_namespace_name(reltup->relnamespace);
result = quote_qualified_identifier(nspname, NameStr(reltup->relname));
ReleaseSysCache(tp);
return result;
}
static remoteConn *
getConnectionByName(const char *name)
{
remoteConnHashEnt *hentry;
char key[NAMEDATALEN];
if (!remoteConnHash)
remoteConnHash = createConnHash();
MemSet(key, 0, NAMEDATALEN);
snprintf(key, NAMEDATALEN - 1, "%s", name);
hentry = (remoteConnHashEnt *) hash_search(remoteConnHash,
key, HASH_FIND, NULL);
if (hentry)
return (hentry->rconn);
return (NULL);
}
static HTAB *
createConnHash(void)
{
HASHCTL ctl;
ctl.keysize = NAMEDATALEN;
ctl.entrysize = sizeof(remoteConnHashEnt);
return hash_create("Remote Con hash", NUMCONN, &ctl, HASH_ELEM);
}
static void
createNewConnection(const char *name, remoteConn * rconn)
{
remoteConnHashEnt *hentry;
bool found;
char key[NAMEDATALEN];
if (!remoteConnHash)
remoteConnHash = createConnHash();
MemSet(key, 0, NAMEDATALEN);
snprintf(key, NAMEDATALEN - 1, "%s", name);
hentry = (remoteConnHashEnt *) hash_search(remoteConnHash, key,
HASH_ENTER, &found);
if (found)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("duplicate connection name")));
hentry->rconn = rconn;
strlcpy(hentry->name, name, sizeof(hentry->name));
}
static void
deleteConnection(const char *name)
{
remoteConnHashEnt *hentry;
bool found;
char key[NAMEDATALEN];
if (!remoteConnHash)
remoteConnHash = createConnHash();
MemSet(key, 0, NAMEDATALEN);
snprintf(key, NAMEDATALEN - 1, "%s", name);
hentry = (remoteConnHashEnt *) hash_search(remoteConnHash,
key, HASH_REMOVE, &found);
if (!hentry)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("undefined connection name")));
}
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