/*BEGIN_LEGAL 
Intel Open Source License 

Copyright (c) 2002-2014 Intel Corporation. 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 Intel Corporation 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 INTEL OR
ITS 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.
END_LEGAL */

// features.h does not exist on FreeBSD
#ifndef TARGET_BSD
// features initializes the system's state, including the state of __USE_GNU
#include <features.h>
#endif

// If __USE_GNU is defined, we don't need to do anything.
// If we defined it ourselves, we need to undefine it later.
#ifndef __USE_GNU
    #define __USE_GNU
    #define APP_UNDEF_USE_GNU
#endif

#include <ucontext.h>

// If we defined __USE_GNU ourselves, we need to undefine it here.
#ifdef APP_UNDEF_USE_GNU
    #undef __USE_GNU
    #undef APP_UNDEF_USE_GNU
#endif


#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <assert.h>
#include <setjmp.h>
#include <sys/types.h>
#include <linux/unistd.h>
#include <errno.h>

ucontext_t *p_saved_ctxt;
unsigned    savedESP;

void install_signal_handlers(void);
void segv_signal_handler(int, siginfo_t *, void *);
void usr2_signal_handler(int, siginfo_t *, void *);
void generate_segv(int val);

void printSignalMask()
{
  sigset_t maskSet;
  int maskBits;
  sigprocmask(0, NULL, &maskSet);
  int i;
  for (i=32; i>0; i--)
    maskBits = (maskBits << 1) | sigismember(&maskSet, i); 
  printf("signal mask: 0x%0.8x\n", maskBits);
}

void install_signal_handlers() {
  //printf("installing signal handlers\n");
  int ret_val;
  struct sigaction s_sigaction;
  struct sigaction *p_sigaction = &s_sigaction;

  /* Register the signal hander using the siginfo interface*/
  p_sigaction->sa_sigaction = segv_signal_handler;
  p_sigaction->sa_flags = SA_SIGINFO;

  /* mask all other signals */
  sigfillset(&p_sigaction->sa_mask);

  ret_val = sigaction(SIGSEGV, p_sigaction, NULL);
  if(ret_val) {
    perror("ERROR, sigaction failed");
    exit(1);
  }

  p_sigaction->sa_sigaction = usr2_signal_handler;
  p_sigaction->sa_flags = SA_SIGINFO;

  ret_val = sigaction(SIGUSR2, p_sigaction, NULL);
  if(ret_val) {
    perror("ERROR, sigaction failed");
    exit(1);
  }
}

void generate_segv(int val) {
printf("bla segv\n");
  int *p = 0;

  printf("EIP of segfault: 0x%x\n", &&segfault);

  __asm__ __volatile__ (
           "movl $0x600D1, %eax;\
            movl $0x600D2, %ebx;\
            movl $0x600D3, %ecx;\
            movl $0x600D4, %edx;\
            movl $0x600D5, %edi;\
            movl $0x600D6, %esi;\
            movl $0x600D7, %ebp");

 segfault:
  __asm__ __volatile__ (
           "movl (0x0), %ecx");
}

void segv_signal_handler(int signum, siginfo_t *siginfo, void *_uctxt) {
printf("bla segv handler\n");
  int ret_val;
  ucontext_t *uctxt = (ucontext_t *)_uctxt;
  ucontext_t signal_ctxt;
  pid_t tid;

  printf("signal %d (captured EIP: 0x%x)\n", signum,
         uctxt->uc_mcontext.gregs[REG_EIP]);

  savedESP = uctxt->uc_mcontext.gregs[REG_ESP];
  printf("ESP saved\n" );
  printf("EDI: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EDI]);
  printf("ESI: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_ESI]);
  printf("EBP: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EBP]);
  printf("EBX: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EBX]);
  printf("EDX: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EDX]);
  printf("ECX: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_ECX]);
  printf("EAX: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EAX]);
  printf("EIP: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EIP]);
  printf("EFL: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EFL]);

  tid = getpid();
  ret_val = kill(tid, SIGUSR2);
}

void usr2_signal_handler(int signum, siginfo_t *siginfo, void *_uctxt) {
printf("bla u2\n");
  int ret_val;
  ucontext_t *uctxt = (ucontext_t *)_uctxt;
  ucontext_t signal_ctxt;
  pid_t tid;

  printf("signal %d (captured EIP: 0x%x)\n", signum,
         uctxt->uc_mcontext.gregs[REG_EIP]);

  printf("ESP diff from saved: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_ESP] - savedESP);
  printf("EDI: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EDI]);
  printf("ESI: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_ESI]);
  printf("EBP: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EBP]);
  printf("EBX: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EBX]);
  printf("EDX: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EDX]);
  printf("ECX: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_ECX]);
  printf("EAX: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EAX]);
  printf("EIP: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EIP]);
  // NOTE!
  // Possible bug in pin:  the resume flags don't match when running natively versus under pin
  //printf("EFL: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EFL]);

  // Change contexts

  uctxt->uc_mcontext.gregs[REG_EDI] = p_saved_ctxt->uc_mcontext.gregs[REG_EDI];
  uctxt->uc_mcontext.gregs[REG_ESI] = p_saved_ctxt->uc_mcontext.gregs[REG_ESI];
  uctxt->uc_mcontext.gregs[REG_EBP] = p_saved_ctxt->uc_mcontext.gregs[REG_EBP];
  uctxt->uc_mcontext.gregs[REG_ESP] = p_saved_ctxt->uc_mcontext.gregs[REG_ESP];
  uctxt->uc_mcontext.gregs[REG_EBX] = p_saved_ctxt->uc_mcontext.gregs[REG_EBX];
  uctxt->uc_mcontext.gregs[REG_EDX] = p_saved_ctxt->uc_mcontext.gregs[REG_EDX];
  uctxt->uc_mcontext.gregs[REG_ECX] = p_saved_ctxt->uc_mcontext.gregs[REG_ECX];
  uctxt->uc_mcontext.gregs[REG_EAX] = p_saved_ctxt->uc_mcontext.gregs[REG_EAX];
  uctxt->uc_mcontext.gregs[REG_EIP] = p_saved_ctxt->uc_mcontext.gregs[REG_EIP];
  uctxt->uc_mcontext.gregs[REG_EFL] = p_saved_ctxt->uc_mcontext.gregs[REG_EFL];

  // getcontext() doesn't appear to properly set the segment registers,
  // so don't mess with them.
  //uctxt->uc_mcontext.gregs[REG_CS] = p_saved_ctxt->uc_mcontext.gregs[REG_CS];
  //uctxt->uc_mcontext.gregs[REG_SS] = p_saved_ctxt->uc_mcontext.gregs[REG_SS];
  //uctxt->uc_mcontext.gregs[REG_DS] = p_saved_ctxt->uc_mcontext.gregs[REG_DS];
  //uctxt->uc_mcontext.gregs[REG_ES] = p_saved_ctxt->uc_mcontext.gregs[REG_ES];
  //uctxt->uc_mcontext.gregs[REG_FS] = p_saved_ctxt->uc_mcontext.gregs[REG_FS];
  //uctxt->uc_mcontext.gregs[REG_GS] = p_saved_ctxt->uc_mcontext.gregs[REG_GS];

  free(p_saved_ctxt);
  p_saved_ctxt = 0;
}

int main(int argc, char **argv) {
  int ret_val;
  p_saved_ctxt = malloc(sizeof(ucontext_t));
  //printf("important 0x%0.8x\n",p_saved_ctxt);

  install_signal_handlers();
  
  //printf("important2 0x%0.8x\n",p_saved_ctxt);

  int tmp = getcontext(p_saved_ctxt);
  ret_val = tmp;
  if (tmp) {
    perror("ERROR, getcontext failed\n");
    printf("%d, %d\n",ret_val,errno);
    exit(1);
  }
 
  printf("bygal2\n");

  p_saved_ctxt->uc_mcontext.gregs[REG_EIP] = (int)&&safe_exit;

  generate_segv(1);

 safe_exit:  
  printf("safe exit\n");
  printSignalMask();

  return 0;
}
