/*
 * 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 test verifies that Pin can change system call numbers and arguments.
 * Use in conjuction with the "change_syscall.c" application.
 */

#include <sys/syscall.h>
#include <signal.h>
#include <string.h>
#include "pin.H"

BOOL IsSigaction(ADDRINT sysnum)
{
#ifdef SYS_sigaction
    if (sysnum == SYS_sigaction)
        return TRUE;
#endif
#ifdef SYS_rt_sigaction
    if (sysnum == SYS_rt_sigaction)
        return TRUE;
#endif
    return FALSE;
}


VOID OnSyscallEntry(THREADID threadIndex, CONTEXT *ctxt, SYSCALL_STANDARD std, VOID *v)
{
    ADDRINT sysnum = PIN_GetSyscallNumber(ctxt, std);
    ADDRINT arg0 = PIN_GetSyscallArgument(ctxt, std, 0);

#if defined(TARGET_MAC)
# if defined(TARGET_IA32E)
    // Extract the syscall number without the UNIX mask
    sysnum = sysnum & (~(0xFF << 24));
# else
    // Extract the syscall number without the int80 mask
    sysnum = sysnum & 0xFFFF;
# endif
#endif

    char* filetoopen = NULL;
#ifdef SYS_openat
    if (sysnum == SYS_openat)
    {
        // open() is implemented using openat() in newer Bionic versions. The file is held in the second argument.
        ADDRINT arg1 = (PIN_GetSyscallArgument(ctxt, std, 1));
        filetoopen = reinterpret_cast<char *>(arg1);
    }
#endif
    if (sysnum == SYS_open)
    {
        filetoopen = reinterpret_cast<char *>(arg0);
    }
    if (filetoopen != NULL && strncmp(filetoopen, "does-not-exist1", sizeof("does-not-exist1")-1) == 0)
    {
        PIN_SetSyscallNumber(ctxt, std, SYS_getpid);
    }

    if (IsSigaction(sysnum) && (arg0 == SIGUSR1))
    {
        PIN_SetSyscallNumber(ctxt, std, SYS_getpid);
    }

    if (filetoopen && strncmp(filetoopen, "does-not-exist2", sizeof("does-not-exist2")-1) == 0)
    {
        PIN_SetSyscallNumber(ctxt, std, SYS_exit);
        PIN_SetSyscallArgument(ctxt, std, 0, 0);
    }
}


int main(int argc, char * argv[])
{
    PIN_Init(argc, argv);

    PIN_AddSyscallEntryFunction(OnSyscallEntry, 0);

    PIN_StartProgram();
    return 0;
}