/*
 * Copyright (C) 1996-1998 Ilya Ryzhenkov (orangy@inetlab.com)
 * This file maintains SIGSEGV handling
 */
#include "helpdefs.h"
#include "dlm.h"
#include "dlmimage.h"
#include "dlm_sym.h"
#include <setjmp.h>
#include <sys/exceptn.h>
#include <signal.h>

#define SIGSEGV_TOLERANCE 64
extern unsigned long __djgpp_selector_limit;
#define excp __djgpp_exception_state

static unsigned long max,tmp,base,idx,min,i;
static TDlm *dlm;
/*
typedef void (*terminate_handler)();
terminate_handler set_terminate__FPFv_v(terminate_handler);
*/
//static void (*old_terminate)();
//extern void (*__terminate_func)();


void print_name(unsigned int eip)
{
 char *crop_dlm;
 printf("  0x%08x ",eip);
 _sym_dlmsearch();
 while ((dlm=_sym_dlmnext()))
  {
    base=(unsigned long)dlm->Base;
    if (base<=eip && base+dlm->VSize>=eip) break;
  }
 if (dlm)
  {
   max=0;
   idx=0xFFFFFFFF;
   for	(i=0; i<dlm->NumSym; i++)
   if (!(dlm->Symbols[i].e_flags&(DLMSYM_IMPORT|DLMSYM_COMMON)))
    {
     tmp=dlm->Symbols[i].e_value+base;
     if (tmp<=eip && tmp>max) { max=tmp; idx=i; }
    }
   if (idx!=0xFFFFFFFF)
   {
    if (dlm->Symbols[idx].e_name!=DLMSYM_NONAME)
       printf(" SYM: %s",dlm->Symbols[idx].e_name+dlm->Strings);
      else
       printf(" SYM: #%ld ",idx);
    printf("+0x%lx",eip-dlm->Symbols[idx].e_value-base);
   }
   crop_dlm=strrchr(dlm->filename,'/');
   printf(" DLM: %s [0x%lx]",crop_dlm?crop_dlm+1:dlm->filename,base);
 }
}

void show_call_frame(void)
{
  unsigned *vbp, *vbp_new, *tos;
  unsigned veip;
  int max=0;

  tos = (unsigned *)__djgpp_selector_limit;
  vbp = (unsigned *)__djgpp_exception_state->__ebp;
  printf("\nDLM call frame traceback :\n");
  while (((unsigned)vbp >= __djgpp_exception_state->__esp) && (vbp < tos))
  {
    vbp_new = (unsigned *)*vbp;
    if (vbp_new == 0) break;
    veip = *(vbp + 1);
    print_name(veip); puts("");
    vbp = vbp_new;
    if (++max == 10) break;
  }
}


void _dlm_sigsegv(int sig)
{
 unsigned long eip=excp->__eip; /* Where error occured */
 void *symaddr;
 signal(SIGSEGV,SIG_DFL);
 printf("\nDLM -> Exiting due to signal SIGSEGV at\n");
 print_name(eip);
 if (dlm)
 {
  min=eip+SIGSEGV_TOLERANCE;
  idx=0xFFFFFFFF;
  for  (i=0; i<dlm->NumRel; i++)
   {
    tmp=dlm->Relocs[i].r_vaddr+base;
    if (tmp>=eip && tmp<min) { min=tmp; idx=i; }
   }
  if (idx!=0xFFFFFFFF)
   {
    symaddr=_sym_find_export(dlm->Strings+dlm->Symbols[dlm->Relocs[idx].r_symndx].e_name,0);
    if (!symaddr)
      printf("\n      possibly because of undefined reference to symbol '%s'\n",
	    dlm->Strings+dlm->Symbols[dlm->Relocs[idx].r_symndx].e_name);
      else
       printf("\n     the reason cannot be detected. try compiling without -O switch.\n");
   }
 }
 show_call_frame();
 exit(-1);
}

void _dlm_sig_invalid_new(unsigned long eip,char *name)
{
 printf("\nExiting due to invalid creation class `%s'\nError was at ",name);
 print_name(eip);
 exit(-1);
}

void _dlm_terminate()
{
 printf("\nExiting due to unexpected excpetion thrown\n");
 show_call_frame();
 exit(-1);
}

void _dlm_init_signal_handlers()
{
 signal(SIGSEGV,_dlm_sigsegv);
 //old_terminate=set_terminate__FPFv_v(_dlm_terminate);
 //__terminate_func=_dlm_terminate;
}

void _dlm_reset_signal_handlers()
{
 signal(SIGSEGV,SIG_DFL);
 //set_terminate__FPFv_v(old_terminate);
// __terminate_func=old_terminate;
}