/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright 2007 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ #pragma ident "%Z%%M% %I% %E% SMI" #include <stdint.h> #include <stdlib.h> #include <strings.h> int baz(void) { return (8); } static int foo(void) { /* * In order to assure that our helper is properly employed to identify * the frame, we're going to trampoline through data. */ uint8_t instr[] = { 0x55, /* pushl %ebp */ 0x8b, 0xec, /* movl %esp, %ebp */ 0xe8, 0x0, 0x0, 0x0, 0x0, /* call baz */ 0x8b, 0xe5, /* movl %ebp, %esp */ 0x5d, /* popl %ebp */ 0xc3 /* ret */ }; uint8_t *fp = malloc(sizeof (instr)); /* * Do our little relocation dance. */ *((int *)&instr[4]) = (uintptr_t)baz - (uintptr_t)&fp[8]; /* * Copy the code to the heap (it's a pain to build in ON with an * executable stack). */ bcopy(instr, fp, sizeof (instr)); (*(int (*)(void))fp)(); free(fp); return (0); } int main(int argc, char **argv) { for (;;) { foo(); } return (0); } |