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64 lines
1.8 KiB
C++
64 lines
1.8 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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*
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* The contents of this file are subject to the Netscape Public License
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* Version 1.0 (the "NPL"); you may not use this file except in
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* compliance with the NPL. You may obtain a copy of the NPL at
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* http://www.mozilla.org/NPL/
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*
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* Software distributed under the NPL is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
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* for the specific language governing rights and limitations under the
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* NPL.
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*
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* The Initial Developer of this code under the NPL is Netscape
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* Communications Corporation. Portions created by Netscape are
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* Copyright (C) 1998 Netscape Communications Corporation. All Rights
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* Reserved.
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*/
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#include <stdio.h>
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#include <signal.h>
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#include <asm/sigcontext.h>
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int old_instruction;
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int
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SetBreakPoint(void *pc)
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{
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old_instruction = *((unsigned char *) pc);
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*((unsigned char *) pc) = 0xcc; /* break point opcode */
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#ifdef DEBUG
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fprintf(stderr, "breakpoint at: %x\n", (unsigned int) pc);
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#endif
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/* Need to flush icache here */
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return old_instruction;
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}
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extern "C" void
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sigtrap_handler(int sig, struct sigcontext_struct context)
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{
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#ifdef DEBUG
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fprintf(stderr, "Handler: Restoring old instruction\n");
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fprintf(stderr, "ip: %x\n", (unsigned int) context.eip);
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#endif
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/* Learnt this the hard way. eip points to the next instruction */
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(*((unsigned char *) (context.eip -1))) = old_instruction;
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context.eip = context.eip - 1;
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/* Send a debugger event and do all kinds of things */
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return;
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}
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void
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SetupBreakPointHandler()
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{
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struct sigaction sigtrap_action;
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sigemptyset(&sigtrap_action.sa_mask);
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sigtrap_action.sa_flags = 0;
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sigtrap_action.sa_handler = (__sighandler_t) sigtrap_handler;
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sigaction(SIGTRAP, &sigtrap_action, NULL);
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}
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