begun implementing rsyslog virtual machine (vm class)

1 files changed, 221 insertions, 0 deletions

diff --git a/vm.c b/vm.c
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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:
+ */