/*
 * Copyright (c) 2006-2009 The Regents of The University of Michigan
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Authors: Ali Saidi
 *          Gabe Black
 */

#include <iostream>
#include <errno.h>
#include <stdint.h>
#include <cstring>

#include "tracechild_arm.hh"

using namespace std;

const char* ARMTraceChild::regNames[numregs] = {
    "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
    "r8", "r9", "r10", "fp", "r12", "sp", "lr", "pc",
    "cpsr" };


ARMTraceChild::ARMTraceChild()
{
    for (int x = 0; x < numregs; x++) {
        memset(&regs, 0, sizeof(regs));
        memset(&oldregs, 0, sizeof(regs));
        regDiffSinceUpdate[x] = false;
    }
}

bool ARMTraceChild::sendState(int socket)
{
    uint32_t regVal = 0;
    uint32_t message[numregs + 1];
    int pos = 1;
    message[0] = 0;
    for (int x = 0; x < numregs; x++) {
        if (regDiffSinceUpdate[x]) {
            message[0] = message[0] | (1 << x);
            message[pos++] = getRegVal(x);
        }
    }

    size_t sent = 0;
    size_t toSend = pos * sizeof(message[0]);
    uint8_t *messagePtr = (uint8_t *)message;
    while (toSend != 0) {
        sent = write(socket, messagePtr, toSend);
        if (sent == -1) {
            cerr << "Write failed! " << strerror(errno) << endl;
            tracing = false;
            return false;
        }
        toSend -= sent;
        messagePtr += sent;
    }
    
    return true;
}

uint32_t ARMTraceChild::getRegs(user_regs &myregs, int num)
{
    assert(num < numregs && num >= 0);
    return myregs.uregs[num];
}

bool ARMTraceChild::update(int pid)
{
    oldregs = regs;
    if(ptrace(PTRACE_GETREGS, pid, 0, &regs) != 0)
    {
        cerr << "update: " << strerror(errno) << endl;
        return false;
    }
 
    for(unsigned int x = 0; x < numregs; x++)
        regDiffSinceUpdate[x] = (getRegVal(x) != getOldRegVal(x));
    return true;
}

int64_t ARMTraceChild::getRegVal(int num)
{
        return getRegs(regs, num);
}

int64_t ARMTraceChild::getOldRegVal(int num)
{
        return getRegs(oldregs,  num);
}

char * ARMTraceChild::printReg(int num)
{
        sprintf(printBuffer, "0x%08X", (uint32_t)getRegVal(num));
        return printBuffer;
}

ostream & ARMTraceChild::outputStartState(ostream & os)
{
    uint32_t sp = getSP();
    uint32_t pc = getPC();
    uint32_t highestInfo = 0;
    char obuf[1024];
    sprintf(obuf, "Initial stack pointer = 0x%08x\n", sp);
    os << obuf;
    sprintf(obuf, "Initial program counter = 0x%08x\n", pc);
    os << obuf;

    //Output the argument count
    int32_t cargc = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
    sprintf(obuf, "0x%08x: Argc = 0x%08x\n", sp, cargc);
    os << obuf;
    sp += 4;

    //Output argv pointers
    int argCount = 0;
    int32_t cargv;
    do
    {
        cargv = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
        sprintf(obuf, "0x%08x: argv[%d] = 0x%08x\n",
                sp, argCount++, cargv);
        if(cargv)
            if(highestInfo < cargv)
                highestInfo = cargv;
        os << obuf;
        sp += 4;
    } while(cargv);

    //Output the envp pointers
    int envCount = 0;
    uint32_t cenvp;
    do
    {
        cenvp = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
        sprintf(obuf, "0x%08x: envp[%d] = 0x%08x\n",
                sp, envCount++, cenvp);
        os << obuf;
        sp += 4;
    } while(cenvp);
    uint32_t auxType, auxVal;
    do
    {
        auxType = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
        sp += 4;
        auxVal = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
        sp += 4;
        sprintf(obuf, "0x%08x: Auxiliary vector = {0x%08x, 0x%08x}\n",
                sp - 8, auxType, auxVal);
        os << obuf;
    } while(auxType != 0 || auxVal != 0);
    //Print out the argument strings, environment strings, and file name.
    string current;
    uint32_t buf;
    uint32_t currentStart = sp;
    bool clearedInitialPadding = false;
    do
    {
        buf = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
        char * cbuf = (char *)&buf;
        for(int x = 0; x < sizeof(uint32_t); x++)
        {
            if(cbuf[x])
                current += cbuf[x];
            else
            {
                sprintf(obuf, "0x%08x: \"%s\"\n",
                        currentStart, current.c_str());
                os << obuf;
                current = "";
                currentStart = sp + x + 1;
            }
        }
        sp += 4;
        clearedInitialPadding = clearedInitialPadding || buf != 0;
    } while(!clearedInitialPadding || buf != 0 || sp <= highestInfo);
    return os;
}

bool ARMTraceChild::step()
{
    const uint32_t bkpt_inst = 0xe7f001f0;

    uint32_t lr = getRegVal(14);
    uint32_t pc = getPC();
    uint32_t lrOp;

    // Since ARM uses software breakpoints behind the scenes, they don't work
    // in read only areas like the page of routines provided by the kernel. The
    // link register generally holds the address the process wants to the
    // kernel to return to after it's done, so we'll install a software
    // breakpoint there. If the lr happens to point to the next instruction
    // we'll leave out our breakpoint to avoid an infinite loop. This isn't a
    // fool proof strategy, but it should work well in all the reasonable
    // scenarios I can think of right now.

    if (pc != lr) {
        lrOp = ptrace(PTRACE_PEEKDATA, pid, lr, 0);
        ptrace(PTRACE_POKEDATA, pid, lr, bkpt_inst);
    }
    ptraceSingleStep();
    if (pc != lr) {
        ptrace(PTRACE_POKEDATA, pid, lr, lrOp);
    }
}


TraceChild * genTraceChild()
{
    return new ARMTraceChild;
}