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/* vm.c - the arithmetic stack of a virtual machine.
*
* Module begun 2008-02-22 by Rainer Gerhards
*
* Copyright 2008 Rainer Gerhards and Adiscon GmbH.
*
* This file is part of rsyslog.
*
* Rsyslog is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Rsyslog is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Rsyslog. If not, see <http://www.gnu.org/licenses/>.
*
* A copy of the GPL can be found in the file "COPYING" in this distribution.
*/
#include "config.h"
#include <stdlib.h>
#include <assert.h>
#include "rsyslog.h"
#include "obj.h"
#include "vm.h"
/* static data */
DEFobjStaticHelpers
DEFobjCurrIf(vmstk)
/* ------------------------------ instruction set implementation ------------------------------ *
* The following functions implement the VM's instruction set.
*/
#define BEGINop(instruction) \
static rsRetVal op##instruction(vm_t *pThis, vmop_t *pOp) \
{ \
DEFiRet;
#define CODESTARTop(instruction) \
ISOBJ_TYPE_assert(pThis, vm); \
ISOBJ_TYPE_assert(pOp, vmop);
#define ENDop(instruction) \
RETiRet; \
}
BEGINop(OR) /* remember to set the instruction also in the ENDop macro! */
// var_t *pVar[2];
var_t *operand1;
var_t *operand2;
CODESTARTop(OR)
// Pop(2, &pVar); --> should also do the conversion outlined below
vmstk.Pop(pThis->pStk, &operand1);
vmstk.Pop(pThis->pStk, &operand2);
// TODO: implement
/* We must check data types and find out on which data type the
* operation needs to be performed. This may result in some data types
* being converted.
*
* Current school of thought:
* op1 op2 operation data type
* string string string
* string number number if op1 can be converted to number, string else
* date string date if op1 can be converted to date, string else
* number number number
* date number string (maybe we can do better?)
* date date date
*
* If a boolean value is required, we need to have a number inside the
* operand. If it is not, conversion rules to number apply. Once we
* have a number, things get easy: 0 is false, anything else is true.
* Please note that due to this conversion rules, "0" becomes false
* while "-4712" becomes true. Using a date as boolen is not a good
* idea. Depending on the ultimate conversion rules, it may always
* become true or false. As such, using dates as booleans is
* prohibited and the result defined to be undefined.
*/
vmstk.Push(pThis->pStk, operand1); /* result */
ENDop(OR)
BEGINop(AND) /* remember to set the instruction also in the ENDop macro! */
var_t *operand1;
var_t *operand2;
CODESTARTop(AND)
vmstk.Pop(pThis->pStk, &operand1);
vmstk.Pop(pThis->pStk, &operand2);
// TODO: implement
vmstk.Push(pThis->pStk, operand1); /* result */
ENDop(AND)
BEGINop(POP) /* remember to set the instruction also in the ENDop macro! */
CODESTARTop(POP)
/* TODO: implement */
ENDop(POP)
BEGINop(PUSHCONSTANT) /* remember to set the instruction also in the ENDop macro! */
CODESTARTop(PUSHCONSTANT)
vmstk.Push(pThis->pStk, pOp->operand.pVar);
ENDop(PUSHCONSTANT)
/* ------------------------------ end instruction set implementation ------------------------------ */
/* Standard-Constructor
*/
BEGINobjConstruct(vm) /* be sure to specify the object type also in END macro! */
ENDobjConstruct(vm)
/* ConstructionFinalizer
* rgerhards, 2008-01-09
*/
static rsRetVal
vmConstructFinalize(vm_t __attribute__((unused)) *pThis)
{
DEFiRet;
ISOBJ_TYPE_assert(pThis, vm);
RETiRet;
}
/* destructor for the vm object */
BEGINobjDestruct(vm) /* be sure to specify the object type also in END and CODESTART macros! */
CODESTARTobjDestruct(vm)
ENDobjDestruct(vm)
/* debugprint for the vm object */
BEGINobjDebugPrint(vm) /* be sure to specify the object type also in END and CODESTART macros! */
CODESTARTobjDebugPrint(vm)
dbgoprint((obj_t*) pThis, "rsyslog virtual machine, currently no state info available\n");
ENDobjDebugPrint(vm)
/* execute a program
*/
static rsRetVal
execProg(vm_t *pThis, vmprg_t *pProg)
{
DEFiRet;
vmop_t *pCurrOp; /* virtual instruction pointer */
ISOBJ_TYPE_assert(pThis, vm);
ISOBJ_TYPE_assert(pProg, vmprg);
#define doOP(OP) case opcode_##OP: CHKiRet(op##OP(pThis, pCurrOp)); break
pCurrOp = pProg->vmopRoot; /* TODO: do this via a method! */
while(pCurrOp != NULL && pCurrOp->opcode != opcode_END_PROG) {
switch(pCurrOp->opcode) {
doOP(OR);
doOP(AND);
doOP(POP);
doOP(PUSHCONSTANT);
default:
ABORT_FINALIZE(RS_RET_INVALID_VMOP);
dbgoprint((obj_t*) pThis, "invalid instruction %d in vmprg\n", pCurrOp->opcode);
break;
}
/* so far, we have plain sequential execution, so on to next... */
pCurrOp = pCurrOp->pNext;
}
#undef doOP
/* if we reach this point, our program has intintionally terminated
* (no error state).
*/
finalize_it:
RETiRet;
}
/* queryInterface function
* rgerhards, 2008-02-21
*/
BEGINobjQueryInterface(vm)
CODESTARTobjQueryInterface(vm)
if(pIf->ifVersion != vmCURR_IF_VERSION) { /* check for current version, increment on each change */
ABORT_FINALIZE(RS_RET_INTERFACE_NOT_SUPPORTED);
}
/* ok, we have the right interface, so let's fill it
* Please note that we may also do some backwards-compatibility
* work here (if we can support an older interface version - that,
* of course, also affects the "if" above).
*/
pIf->oID = OBJvm;
pIf->Construct = vmConstruct;
pIf->ConstructFinalize = vmConstructFinalize;
pIf->Destruct = vmDestruct;
pIf->DebugPrint = vmDebugPrint;
pIf->ExecProg = execProg;
finalize_it:
ENDobjQueryInterface(vm)
/* Initialize the vm class. Must be called as the very first method
* before anything else is called inside this class.
* rgerhards, 2008-02-19
*/
BEGINObjClassInit(vm, 1) /* class, version */
/* request objects we use */
CHKiRet(objUse(vmstk));
/* set our own handlers */
OBJSetMethodHandler(objMethod_DEBUGPRINT, vmDebugPrint);
OBJSetMethodHandler(objMethod_CONSTRUCTION_FINALIZER, vmConstructFinalize);
ENDObjClassInit(vm)
/* vi:set ai:
*/
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