pltcl.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

/**********************************************************************
 * pltcl.c		- PostgreSQL support for Tcl as
 *				  procedural language (PL)
 *
 *	  This software is copyrighted by Jan Wieck - Hamburg.
 *
 *	  The author hereby grants permission  to  use,  copy,	modify,
 *	  distribute,  and	license this software and its documentation
 *	  for any purpose, provided that existing copyright notices are
 *	  retained	in	all  copies  and  that	this notice is included
 *	  verbatim in any distributions. No written agreement, license,
 *	  or  royalty  fee	is required for any of the authorized uses.
 *	  Modifications to this software may be  copyrighted  by  their
 *	  author  and  need  not  follow  the licensing terms described
 *	  here, provided that the new terms are  clearly  indicated  on
 *	  the first page of each file where they apply.
 *
 *	  IN NO EVENT SHALL THE AUTHOR OR DISTRIBUTORS BE LIABLE TO ANY
 *	  PARTY  FOR  DIRECT,	INDIRECT,	SPECIAL,   INCIDENTAL,	 OR
 *	  CONSEQUENTIAL   DAMAGES  ARISING	OUT  OF  THE  USE  OF  THIS
 *	  SOFTWARE, ITS DOCUMENTATION, OR ANY DERIVATIVES THEREOF, EVEN
 *	  IF  THE  AUTHOR  HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH
 *	  DAMAGE.
 *
 *	  THE  AUTHOR  AND	DISTRIBUTORS  SPECIFICALLY	 DISCLAIM	ANY
 *	  WARRANTIES,  INCLUDING,  BUT	NOT  LIMITED  TO,  THE	IMPLIED
 *	  WARRANTIES  OF  MERCHANTABILITY,	FITNESS  FOR  A  PARTICULAR
 *	  PURPOSE,	AND NON-INFRINGEMENT.  THIS SOFTWARE IS PROVIDED ON
 *	  AN "AS IS" BASIS, AND THE AUTHOR	AND  DISTRIBUTORS  HAVE  NO
 *	  OBLIGATION   TO	PROVIDE   MAINTENANCE,	 SUPPORT,  UPDATES,
 *	  ENHANCEMENTS, OR MODIFICATIONS.
 *
 * IDENTIFICATION
 *	  $PostgreSQL: pgsql/src/pl/tcl/pltcl.c,v 1.98.2.2 2006/01/17 17:33:23 tgl Exp $
 *
 **********************************************************************/

#include "postgres.h"

#include <tcl.h>

#include <unistd.h>
#include <fcntl.h>

/* Hack to deal with Tcl 8.4 const-ification without losing compatibility */
#ifndef CONST84
#define CONST84
#endif

#include "access/heapam.h"
#include "catalog/pg_language.h"
#include "catalog/pg_proc.h"
#include "commands/trigger.h"
#include "executor/spi.h"
#include "fmgr.h"
#include "nodes/makefuncs.h"
#include "parser/parse_type.h"
#include "tcop/tcopprot.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/syscache.h"
#include "utils/typcache.h"


#if defined(UNICODE_CONVERSION) && TCL_MAJOR_VERSION == 8 \
	&& TCL_MINOR_VERSION > 0

#include "mb/pg_wchar.h"

static unsigned char *
utf_u2e(unsigned char *src)
{
	return pg_do_encoding_conversion(src, strlen(src), PG_UTF8, GetDatabaseEncoding());
}

static unsigned char *
utf_e2u(unsigned char *src)
{
	return pg_do_encoding_conversion(src, strlen(src), GetDatabaseEncoding(), PG_UTF8);
}

#define PLTCL_UTF
#define UTF_BEGIN	 do { \
					unsigned char *_pltcl_utf_src; \
					unsigned char *_pltcl_utf_dst
#define UTF_END		 if (_pltcl_utf_src!=_pltcl_utf_dst) \
					pfree(_pltcl_utf_dst); } while (0)
#define UTF_U2E(x)	 (_pltcl_utf_dst=utf_u2e(_pltcl_utf_src=(x)))
#define UTF_E2U(x)	 (_pltcl_utf_dst=utf_e2u(_pltcl_utf_src=(x)))
#else							/* !PLTCL_UTF */

#define  UTF_BEGIN
#define  UTF_END
#define  UTF_U2E(x)  (x)
#define  UTF_E2U(x)  (x)
#endif   /* PLTCL_UTF */


/**********************************************************************
 * The information we cache about loaded procedures
 **********************************************************************/
typedef struct pltcl_proc_desc
{
	char	   *proname;
	TransactionId fn_xmin;
	CommandId	fn_cmin;
	bool		fn_readonly;
	bool		lanpltrusted;
	FmgrInfo	result_in_func;
	Oid			result_typioparam;
	int			nargs;
	FmgrInfo	arg_out_func[FUNC_MAX_ARGS];
	bool		arg_is_rowtype[FUNC_MAX_ARGS];
} pltcl_proc_desc;


/**********************************************************************
 * The information we cache about prepared and saved plans
 **********************************************************************/
typedef struct pltcl_query_desc
{
	char		qname[20];
	void	   *plan;
	int			nargs;
	Oid		   *argtypes;
	FmgrInfo   *arginfuncs;
	Oid		   *argtypioparams;
} pltcl_query_desc;


/**********************************************************************
 * Global data
 **********************************************************************/
static bool pltcl_pm_init_done = false;
static bool pltcl_be_init_done = false;
static Tcl_Interp *pltcl_hold_interp = NULL;
static Tcl_Interp *pltcl_norm_interp = NULL;
static Tcl_Interp *pltcl_safe_interp = NULL;
static Tcl_HashTable *pltcl_proc_hash = NULL;
static Tcl_HashTable *pltcl_norm_query_hash = NULL;
static Tcl_HashTable *pltcl_safe_query_hash = NULL;

/* these are saved and restored by pltcl_call_handler */
static FunctionCallInfo pltcl_current_fcinfo = NULL;
static pltcl_proc_desc *pltcl_current_prodesc = NULL;

/**********************************************************************
 * Forward declarations
 **********************************************************************/
static void pltcl_init_all(void);
static void pltcl_init_interp(Tcl_Interp *interp);

static void pltcl_init_load_unknown(Tcl_Interp *interp);

Datum		pltcl_call_handler(PG_FUNCTION_ARGS);
Datum		pltclu_call_handler(PG_FUNCTION_ARGS);
void		pltcl_init(void);

static Datum pltcl_func_handler(PG_FUNCTION_ARGS);

static HeapTuple pltcl_trigger_handler(PG_FUNCTION_ARGS);

static pltcl_proc_desc *compile_pltcl_function(Oid fn_oid, Oid tgreloid);

static int pltcl_elog(ClientData cdata, Tcl_Interp *interp,
		   int argc, CONST84 char *argv[]);
static int pltcl_quote(ClientData cdata, Tcl_Interp *interp,
			int argc, CONST84 char *argv[]);
static int pltcl_argisnull(ClientData cdata, Tcl_Interp *interp,
				int argc, CONST84 char *argv[]);
static int pltcl_returnnull(ClientData cdata, Tcl_Interp *interp,
				 int argc, CONST84 char *argv[]);

static int pltcl_SPI_execute(ClientData cdata, Tcl_Interp *interp,
				  int argc, CONST84 char *argv[]);
static int pltcl_process_SPI_result(Tcl_Interp *interp,
						 CONST84 char *arrayname,
						 CONST84 char *loop_body,
						 int spi_rc,
						 SPITupleTable *tuptable,
						 int ntuples);
static int pltcl_SPI_prepare(ClientData cdata, Tcl_Interp *interp,
				  int argc, CONST84 char *argv[]);
static int pltcl_SPI_execute_plan(ClientData cdata, Tcl_Interp *interp,
					   int argc, CONST84 char *argv[]);
static int pltcl_SPI_lastoid(ClientData cdata, Tcl_Interp *interp,
				  int argc, CONST84 char *argv[]);

static void pltcl_set_tuple_values(Tcl_Interp *interp, CONST84 char *arrayname,
					   int tupno, HeapTuple tuple, TupleDesc tupdesc);
static void pltcl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc,
						   Tcl_DString *retval);


/*
 * This routine is a crock, and so is everyplace that calls it.  The problem
 * is that the cached form of pltcl functions/queries is allocated permanently
 * (mostly via malloc()) and never released until backend exit.  Subsidiary
 * data structures such as fmgr info records therefore must live forever
 * as well.  A better implementation would store all this stuff in a per-
 * function memory context that could be reclaimed at need.  In the meantime,
 * fmgr_info_cxt must be called specifying TopMemoryContext so that whatever
 * it might allocate, and whatever the eventual function might allocate using
 * fn_mcxt, will live forever too.
 */
static void
perm_fmgr_info(Oid functionId, FmgrInfo *finfo)
{
	fmgr_info_cxt(functionId, finfo, TopMemoryContext);
}

/**********************************************************************
 * pltcl_init()		- Initialize all that's safe to do in the postmaster
 *
 * DO NOT make this static --- it has to be callable by preload
 **********************************************************************/
void
pltcl_init(void)
{
	/************************************************************
	 * Do initialization only once
	 ************************************************************/
	if (pltcl_pm_init_done)
		return;

#ifdef WIN32
	/* Required on win32 to prevent error loading init.tcl */
	Tcl_FindExecutable("");
#endif

	/************************************************************
	 * Create the dummy hold interpreter to prevent close of
	 * stdout and stderr on DeleteInterp
	 ************************************************************/
	if ((pltcl_hold_interp = Tcl_CreateInterp()) == NULL)
		elog(ERROR, "could not create \"hold\" interpreter");

	/************************************************************
	 * Create the two interpreters
	 ************************************************************/
	if ((pltcl_norm_interp =
		 Tcl_CreateSlave(pltcl_hold_interp, "norm", 0)) == NULL)
		elog(ERROR, "could not create \"normal\" interpreter");
	pltcl_init_interp(pltcl_norm_interp);

	if ((pltcl_safe_interp =
		 Tcl_CreateSlave(pltcl_hold_interp, "safe", 1)) == NULL)
		elog(ERROR, "could not create \"safe\" interpreter");
	pltcl_init_interp(pltcl_safe_interp);

	/************************************************************
	 * Initialize the proc and query hash tables
	 ************************************************************/
	pltcl_proc_hash = (Tcl_HashTable *) malloc(sizeof(Tcl_HashTable));
	pltcl_norm_query_hash = (Tcl_HashTable *) malloc(sizeof(Tcl_HashTable));
	pltcl_safe_query_hash = (Tcl_HashTable *) malloc(sizeof(Tcl_HashTable));
	Tcl_InitHashTable(pltcl_proc_hash, TCL_STRING_KEYS);
	Tcl_InitHashTable(pltcl_norm_query_hash, TCL_STRING_KEYS);
	Tcl_InitHashTable(pltcl_safe_query_hash, TCL_STRING_KEYS);

	pltcl_pm_init_done = true;
}

/**********************************************************************
 * pltcl_init_all()		- Initialize all
 **********************************************************************/
static void
pltcl_init_all(void)
{
	/************************************************************
	 * Execute postmaster-startup safe initialization
	 ************************************************************/
	if (!pltcl_pm_init_done)
		pltcl_init();

	/************************************************************
	 * Any other initialization that must be done each time a new
	 * backend starts:
	 * - Try to load the unknown procedure from pltcl_modules
	 ************************************************************/
	if (!pltcl_be_init_done)
	{
		if (SPI_connect() != SPI_OK_CONNECT)
			elog(ERROR, "SPI_connect failed");
		pltcl_init_load_unknown(pltcl_norm_interp);
		pltcl_init_load_unknown(pltcl_safe_interp);
		if (SPI_finish() != SPI_OK_FINISH)
			elog(ERROR, "SPI_finish failed");
		pltcl_be_init_done = true;
	}
}


/**********************************************************************
 * pltcl_init_interp() - initialize a Tcl interpreter
 **********************************************************************/
static void
pltcl_init_interp(Tcl_Interp *interp)
{
	/************************************************************
	 * Install the commands for SPI support in the interpreter
	 ************************************************************/
	Tcl_CreateCommand(interp, "elog",
					  pltcl_elog, NULL, NULL);
	Tcl_CreateCommand(interp, "quote",
					  pltcl_quote, NULL, NULL);
	Tcl_CreateCommand(interp, "argisnull",
					  pltcl_argisnull, NULL, NULL);
	Tcl_CreateCommand(interp, "return_null",
					  pltcl_returnnull, NULL, NULL);

	Tcl_CreateCommand(interp, "spi_exec",
					  pltcl_SPI_execute, NULL, NULL);
	Tcl_CreateCommand(interp, "spi_prepare",
					  pltcl_SPI_prepare, NULL, NULL);
	Tcl_CreateCommand(interp, "spi_execp",
					  pltcl_SPI_execute_plan, NULL, NULL);
	Tcl_CreateCommand(interp, "spi_lastoid",
					  pltcl_SPI_lastoid, NULL, NULL);
}


/**********************************************************************
 * pltcl_init_load_unknown()	- Load the unknown procedure from
 *				  table pltcl_modules (if it exists)
 **********************************************************************/
static void
pltcl_init_load_unknown(Tcl_Interp *interp)
{
	int			spi_rc;
	int			tcl_rc;
	Tcl_DString unknown_src;
	char	   *part;
	int			i;
	int			fno;

	/************************************************************
	 * Check if table pltcl_modules exists
	 ************************************************************/
	spi_rc = SPI_execute("select 1 from pg_catalog.pg_class "
						 "where relname = 'pltcl_modules'",
						 false, 1);
	SPI_freetuptable(SPI_tuptable);
	if (spi_rc != SPI_OK_SELECT)
		elog(ERROR, "select from pg_class failed");
	if (SPI_processed == 0)
		return;

	/************************************************************
	 * Read all the row's from it where modname = 'unknown' in
	 * the order of modseq
	 ************************************************************/
	Tcl_DStringInit(&unknown_src);

	spi_rc = SPI_execute("select modseq, modsrc from pltcl_modules "
						 "where modname = 'unknown' "
						 "order by modseq",
						 false, 0);
	if (spi_rc != SPI_OK_SELECT)
		elog(ERROR, "select from pltcl_modules failed");

	/************************************************************
	 * If there's nothing, module unknown doesn't exist
	 ************************************************************/
	if (SPI_processed == 0)
	{
		Tcl_DStringFree(&unknown_src);
		SPI_freetuptable(SPI_tuptable);
		elog(WARNING, "module \"unknown\" not found in pltcl_modules");
		return;
	}

	/************************************************************
	 * There is a module named unknown. Resemble the
	 * source from the modsrc attributes and evaluate
	 * it in the Tcl interpreter
	 ************************************************************/
	fno = SPI_fnumber(SPI_tuptable->tupdesc, "modsrc");

	for (i = 0; i < SPI_processed; i++)
	{
		part = SPI_getvalue(SPI_tuptable->vals[i],
							SPI_tuptable->tupdesc, fno);
		if (part != NULL)
		{
			UTF_BEGIN;
			Tcl_DStringAppend(&unknown_src, UTF_E2U(part), -1);
			UTF_END;
			pfree(part);
		}
	}
	tcl_rc = Tcl_GlobalEval(interp, Tcl_DStringValue(&unknown_src));
	Tcl_DStringFree(&unknown_src);
	SPI_freetuptable(SPI_tuptable);
}


/**********************************************************************
 * pltcl_call_handler		- This is the only visible function
 *				  of the PL interpreter. The PostgreSQL
 *				  function manager and trigger manager
 *				  call this function for execution of
 *				  PL/Tcl procedures.
 **********************************************************************/
PG_FUNCTION_INFO_V1(pltcl_call_handler);

/* keep non-static */
Datum
pltcl_call_handler(PG_FUNCTION_ARGS)
{
	Datum		retval;
	FunctionCallInfo save_fcinfo;
	pltcl_proc_desc *save_prodesc;

	/*
	 * Initialize interpreters if first time through
	 */
	pltcl_init_all();

	/*
	 * Ensure that static pointers are saved/restored properly
	 */
	save_fcinfo = pltcl_current_fcinfo;
	save_prodesc = pltcl_current_prodesc;

	PG_TRY();
	{
		/*
		 * Determine if called as function or trigger and call appropriate
		 * subhandler
		 */
		if (CALLED_AS_TRIGGER(fcinfo))
		{
			pltcl_current_fcinfo = NULL;
			retval = PointerGetDatum(pltcl_trigger_handler(fcinfo));
		}
		else
		{
			pltcl_current_fcinfo = fcinfo;
			retval = pltcl_func_handler(fcinfo);