/*
 * 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.
 */

//
// This tool demonstrates how to get the value of the application's
// errno on linux in probe mode.
//
//
// There are symbols called __errno_location in both libc and libpthread.
// This test captures the address of the __errno_location() function in
// one of the libraries and not in the other.   Today, the implementations
// in libc and libpthread point to the same actual location (in a TLS),
// but this assumption is fragile and may change at some time int he future.


#include "pin.H"
#include <iostream>
#include <stdlib.h>
#include <errno.h>
#include "tool_macros.h"
using std::cerr;
using std::endl;


#if defined(TARGET_MAC)
#define ERRNO_SYMBOL ("___error")
#else
#define ERRNO_SYMBOL ("__errno_location")
#endif

typedef ADDRINT * (*ERRNO_LOCATION_FUNPTR)();
ADDRINT pf_errno_location = 0;


/* ===================================================================== */
VOID ToolCheckError()
{
    if ( pf_errno_location != 0 )
    {
        ADDRINT * err_loc = (*(ERRNO_LOCATION_FUNPTR)pf_errno_location)();

        int err_value = *err_loc;

        cerr << "Tool: errno=" << err_value << endl;
    }
    else
        cerr << "Tool: __errno_location() not found." << endl;

}

/* ===================================================================== */
VOID ImageLoad(IMG img, VOID *v)
{

    RTN errno_location_rtn = RTN_FindByName(img, ERRNO_SYMBOL);
    if (RTN_Valid(errno_location_rtn))
    {
        pf_errno_location = RTN_Address(errno_location_rtn);
    }

    if ( IMG_IsMainExecutable( img ))
    {
        PROTO proto = PROTO_Allocate( PIN_PARG(void), CALLINGSTD_DEFAULT,
                                      "CheckError", PIN_PARG_END() );

        RTN rtn = RTN_FindByName(img, C_MANGLE("CheckError"));
        if (RTN_Valid(rtn) && RTN_IsSafeForProbedReplacement(rtn))
        {
            RTN_ReplaceSignatureProbed(rtn, AFUNPTR(ToolCheckError),
                                       IARG_PROTOTYPE, proto,
                                       IARG_END);
        }
        PROTO_Free( proto );
    }
}

/* ===================================================================== */
int main(INT32 argc, CHAR *argv[])
{
    PIN_InitSymbols();

    PIN_Init(argc, argv);

    IMG_AddInstrumentFunction(ImageLoad, 0);

    PIN_StartProgramProbed();

    return 0;
}

/* ===================================================================== */
/* eof */
/* ===================================================================== */