/*
 * Copyright 2002-2019 Intel Corporation.
 * 
 * This software is provided to you as Sample Source Code as defined in the accompanying
 * End User License Agreement for the Intel(R) Software Development Products ("Agreement")
 * section 1.L.
 * 
 * This software and the related documents are provided as is, with no express or implied
 * warranties, other than those that are expressly stated in the License.
 */

#include <iostream>
#include <fstream>
#include <sys/syscall.h>
#include "pin.H"
using std::cerr;
using std::ofstream;
using std::hex;
using std::string;
using std::endl;

// The highest bit value in a pointer
#define HIGHEST_BIT ((ADDRINT)1 << (8 * sizeof(void*) - 1))

// Tool's output file
ofstream OutFile;

// Temporary registers used to rewrite memory operands
REG rewrite_reg[2];

KNOB<string> KnobOutputFile(KNOB_MODE_WRITEONCE, "pintool",
    "o", "malloc_translation.out", "specify output file name");


/*
 * Translates a memory address.
 * malloc() related functions return address with the higest
 * bit on. so, we'll turn this bit off if we get such address.
 */
static ADDRINT TranslateMemRef(ADDRINT ea)
{
    return ea & ~HIGHEST_BIT;
}

/*
 * Pin calls this function everytime it needs to translate a memory address
 */
ADDRINT PIN_FAST_ANALYSIS_CALL memoryCallback(PIN_MEM_TRANS_INFO* memTransInfo, VOID *v)
{
    return TranslateMemRef(memTransInfo->addr);
}

/*
 * Translates address that are sent to syscalls.
 * Currently, we know of only one syscall that are called and requires
 * this translation - which is SYS_open.
 */
VOID SysBefore(ADDRINT num, ADDRINT *arg0, ADDRINT *arg1, ADDRINT *arg2, ADDRINT *arg3, ADDRINT *arg4, ADDRINT *arg5)
{
    switch (num)
    {
        case SYS_open:
            // The filename string needs to be translated
            *arg0 = TranslateMemRef(*arg0);
            break;
        case SYS_openat:
            // The filename string needs to be translated
            *arg1 = TranslateMemRef(*arg1);
            break;
        case SYS_write:
            // The 'buf' argument needs to be translated
            *arg1 = TranslateMemRef(*arg1);
            break;
    }
}

// Pin calls this function every time a new instruction is encountered
VOID Instruction(INS ins, VOID *v)
{
    if (INS_IsSyscall(ins))
    {
        INS_InsertCall(ins, IPOINT_BEFORE, AFUNPTR(SysBefore),
                       IARG_SYSCALL_NUMBER,
                       IARG_SYSARG_REFERENCE, 0, IARG_SYSARG_REFERENCE, 1,
                       IARG_SYSARG_REFERENCE, 2, IARG_SYSARG_REFERENCE, 3,
                       IARG_SYSARG_REFERENCE, 4, IARG_SYSARG_REFERENCE, 5,
                       IARG_END);
    }
    else
    {
        const UINT32 memOps = INS_MemoryOperandCount(ins);
        ASSERTX(memOps <= 2);
        for (UINT32 i = 0 ; i < memOps; i++)
        {
            OutFile << "Instrumenting at " << hex << INS_Address(ins) << " " << INS_Disassemble(ins).c_str() << " operand #" << i << std::endl;
            INS_InsertCall(ins, IPOINT_BEFORE, (AFUNPTR)TranslateMemRef,
                    IARG_MEMORYOP_EA, (ADDRINT)i,
                    IARG_RETURN_REGS, rewrite_reg[i],
                    IARG_END);
            INS_RewriteMemoryOperand(ins, i, rewrite_reg[i]);
        }
    }
}


// This function is called when the application exits
VOID Fini(INT32 code, VOID *v)
{
    OutFile << "Done!" << endl;
    OutFile.close();
}

/* ===================================================================== */
/* Print Help Message                                                    */
/* ===================================================================== */

INT32 Usage()
{
    cerr << "This tool tests memory address translation with malloc replacement" << endl;
    cerr << endl << KNOB_BASE::StringKnobSummary() << endl;
    return -1;
}

/* ===================================================================== */
/* Main                                                                  */
/* ===================================================================== */

int main(int argc, char * argv[])
{
    // Initialize pin
    if (PIN_Init(argc, argv)) return Usage();

    OutFile.open(KnobOutputFile.Value().c_str());

    rewrite_reg[0] = PIN_ClaimToolRegister();
    rewrite_reg[1] = PIN_ClaimToolRegister();

    // Register Instruction to be called to instrument instructions
    INS_AddInstrumentFunction(Instruction, 0);

    // Register memory callback
    PIN_AddMemoryAddressTransFunction(memoryCallback, NULL);

    // Register Fini to be called when the application exits
    PIN_AddFiniFunction(Fini, 0);

    // Start the program, never returns
    PIN_StartProgram();
}