plperl.c

PostgreSQL7.4.6 for Linux

/**********************************************************************
 * plperl.c - perl as a procedural language for PostgreSQL
 *
 * IDENTIFICATION
 *
 *	  This software is copyrighted by Mark Hollomon
 *	 but is shameless cribbed from pltcl.c by Jan Weick.
 *
 *	  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
 *	  $Header: /cvsroot/pgsql/src/pl/plperl/plperl.c,v 1.40 2003/09/04 15:16:39 tgl Exp $
 *
 **********************************************************************/

#include "postgres.h"

/* system stuff */
#include <unistd.h>
#include <fcntl.h>
#include <setjmp.h>

/* postgreSQL stuff */
#include "executor/spi.h"
#include "commands/trigger.h"
#include "fmgr.h"
#include "access/heapam.h"
#include "tcop/tcopprot.h"
#include "utils/syscache.h"
#include "catalog/pg_language.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"

/* perl stuff */
#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
#include "ppport.h"

/* just in case these symbols aren't provided */
#ifndef pTHX_
#define pTHX_
#define pTHX void
#endif


/**********************************************************************
 * The information we cache about loaded procedures
 **********************************************************************/
typedef struct plperl_proc_desc
{
	char	   *proname;
	TransactionId fn_xmin;
	CommandId	fn_cmin;
	bool		lanpltrusted;
	FmgrInfo	result_in_func;
	Oid			result_in_elem;
	int			nargs;
	FmgrInfo	arg_out_func[FUNC_MAX_ARGS];
	Oid			arg_out_elem[FUNC_MAX_ARGS];
	int			arg_is_rel[FUNC_MAX_ARGS];
	SV		   *reference;
}	plperl_proc_desc;


/**********************************************************************
 * Global data
 **********************************************************************/
static int	plperl_firstcall = 1;
static PerlInterpreter *plperl_interp = NULL;
static HV  *plperl_proc_hash = NULL;

/**********************************************************************
 * Forward declarations
 **********************************************************************/
static void plperl_init_all(void);
static void plperl_init_interp(void);

Datum		plperl_call_handler(PG_FUNCTION_ARGS);
void		plperl_init(void);

static Datum plperl_func_handler(PG_FUNCTION_ARGS);

static plperl_proc_desc *compile_plperl_function(Oid fn_oid, bool is_trigger);

static SV  *plperl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc);
static void plperl_init_shared_libs(pTHX);


/*
 * This routine is a crock, and so is everyplace that calls it.  The problem
 * is that the cached form of plperl 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);
}

/**********************************************************************
 * plperl_init()			- Initialize everything that can be
 *							  safely initialized during postmaster
 *							  startup.
 *
 * DO NOT make this static --- it has to be callable by preload
 **********************************************************************/
void
plperl_init(void)
{
	/************************************************************
	 * Do initialization only once
	 ************************************************************/
	if (!plperl_firstcall)
		return;

	/************************************************************
	 * Free the proc hash table
	 ************************************************************/
	if (plperl_proc_hash != NULL)
	{
		hv_undef(plperl_proc_hash);
		SvREFCNT_dec((SV *) plperl_proc_hash);
		plperl_proc_hash = NULL;
	}

	/************************************************************
	 * Destroy the existing Perl interpreter
	 ************************************************************/
	if (plperl_interp != NULL)
	{
		perl_destruct(plperl_interp);
		perl_free(plperl_interp);
		plperl_interp = NULL;
	}

	/************************************************************
	 * Now recreate a new Perl interpreter
	 ************************************************************/
	plperl_init_interp();

	plperl_firstcall = 0;
}

/**********************************************************************
 * plperl_init_all()		- Initialize all
 **********************************************************************/
static void
plperl_init_all(void)
{

	/************************************************************
	 * Execute postmaster-startup safe initialization
	 ************************************************************/
	if (plperl_firstcall)
		plperl_init();

	/************************************************************
	 * Any other initialization that must be done each time a new
	 * backend starts -- currently none
	 ************************************************************/

}


/**********************************************************************
 * plperl_init_interp() - Create the Perl interpreter
 **********************************************************************/
static void
plperl_init_interp(void)
{

	char	   *embedding[3] = {
		"", "-e",

		/*
		 * no commas between the next 5 please. They are supposed to be
		 * one string
		 */
		"require Safe; SPI::bootstrap();"
		"sub ::mksafefunc { my $x = new Safe; $x->permit_only(':default');$x->permit(':base_math');"
		"$x->share(qw[&elog &DEBUG &LOG &INFO &NOTICE &WARNING &ERROR]);"
		" return $x->reval(qq[sub { $_[0] }]); }"
		"sub ::mkunsafefunc {return eval(qq[ sub { $_[0] } ]); }"
	};

	plperl_interp = perl_alloc();
	if (!plperl_interp)
		elog(ERROR, "could not allocate perl interpreter");

	perl_construct(plperl_interp);
	perl_parse(plperl_interp, plperl_init_shared_libs, 3, embedding, NULL);
	perl_run(plperl_interp);

	/************************************************************
	 * Initialize the proc and query hash tables
	 ************************************************************/
	plperl_proc_hash = newHV();

}


/**********************************************************************
 * plperl_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
 *				  perl procedures.
 **********************************************************************/
PG_FUNCTION_INFO_V1(plperl_call_handler);

/* keep non-static */
Datum
plperl_call_handler(PG_FUNCTION_ARGS)
{
	Datum		retval;

	/************************************************************
	 * Initialize interpreter
	 ************************************************************/
	plperl_init_all();

	/************************************************************
	 * Connect to SPI manager
	 ************************************************************/
	if (SPI_connect() != SPI_OK_CONNECT)
		elog(ERROR, "could not connect to SPI manager");

	/************************************************************
	 * Determine if called as function or trigger and
	 * call appropriate subhandler
	 ************************************************************/
	if (CALLED_AS_TRIGGER(fcinfo))
	{
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("cannot use perl in triggers yet")));

		/*
		 * retval = PointerGetDatum(plperl_trigger_handler(fcinfo));
		 */
		/* make the compiler happy */
		retval = (Datum) 0;
	}
	else
		retval = plperl_func_handler(fcinfo);

	return retval;
}


/**********************************************************************
 * plperl_create_sub()		- calls the perl interpreter to
 *		create the anonymous subroutine whose text is in the SV.
 *		Returns the SV containing the RV to the closure.
 **********************************************************************/
static SV  *
plperl_create_sub(char *s, bool trusted)
{
	dSP;
	SV		   *subref;
	int			count;

	ENTER;
	SAVETMPS;
	PUSHMARK(SP);
	XPUSHs(sv_2mortal(newSVpv(s, 0)));
	PUTBACK;

	/*
	 * G_KEEPERR seems to be needed here, else we don't recognize compile
	 * errors properly.  Perhaps it's because there's another level of
	 * eval inside mksafefunc?
	 */
	count = perl_call_pv((trusted ? "mksafefunc" : "mkunsafefunc"),
						 G_SCALAR | G_EVAL | G_KEEPERR);
	SPAGAIN;

	if (count != 1)
	{
		PUTBACK;
		FREETMPS;
		LEAVE;
		elog(ERROR, "didn't get a return item from mksafefunc");
	}

	if (SvTRUE(ERRSV))
	{
		POPs;
		PUTBACK;
		FREETMPS;
		LEAVE;
		elog(ERROR, "creation of function failed: %s", SvPV(ERRSV, PL_na));
	}

	/*
	 * need to make a deep copy of the return. it comes off the stack as a
	 * temporary.
	 */
	subref = newSVsv(POPs);

	if (!SvROK(subref))
	{
		PUTBACK;
		FREETMPS;
		LEAVE;

		/*
		 * subref is our responsibility because it is not mortal
		 */
		SvREFCNT_dec(subref);
		elog(ERROR, "didn't get a code ref");
	}

	PUTBACK;
	FREETMPS;
	LEAVE;

	return subref;
}

/**********************************************************************
 * plperl_init_shared_libs()		-
 *
 * We cannot use the DynaLoader directly to get at the Opcode
 * module (used by Safe.pm). So, we link Opcode into ourselves
 * and do the initialization behind perl's back.
 *
 **********************************************************************/

EXTERN_C void boot_DynaLoader(pTHX_ CV * cv);
EXTERN_C void boot_SPI(pTHX_ CV * cv);

static void
plperl_init_shared_libs(pTHX)
{
	char	   *file = __FILE__;

	newXS("DynaLoader::boot_DynaLoader", boot_DynaLoader, file);
	newXS("SPI::bootstrap", boot_SPI, file);
}

/**********************************************************************
 * plperl_call_perl_func()		- calls a perl function through the RV
 *			stored in the prodesc structure. massages the input parms properly
 **********************************************************************/
static SV  *
plperl_call_perl_func(plperl_proc_desc * desc, FunctionCallInfo fcinfo)
{
	dSP;
	SV		   *retval;
	int			i;
	int			count;

	ENTER;
	SAVETMPS;

	PUSHMARK(SP);
	for (i = 0; i < desc->nargs; i++)
	{
		if (desc->arg_is_rel[i])
		{
			TupleTableSlot *slot = (TupleTableSlot *) fcinfo->arg[i];
			SV		   *hashref;

			Assert(slot != NULL && !fcinfo->argnull[i]);

			/*
			 * plperl_build_tuple_argument better return a mortal SV.
			 */
			hashref = plperl_build_tuple_argument(slot->val,
											  slot->ttc_tupleDescriptor);
			XPUSHs(hashref);
		}
		else
		{
			if (fcinfo->argnull[i])