static void SignalReceived(int signum, siginfo_t * siginfo, void *context)
{
printf("\nProgram received signal %d (%s)\n", signum, sys_siglist[signum]);
// These two lines get the value of RIP register at time of crash, i.e.
// address of instruction that faulted
const int rip_index = 16;
const int rbp_index = 10;
void *rip = (void *)((struct ucontext *)context)->uc_mcontext.gregs[rip_index];
void *rbp = (void *)((struct ucontext *)context)->uc_mcontext.gregs[rbp_index];
// this starter code only prints the symbol addr
// should eventually print [%p] %s (+0x%x) with addr, name, offset arguments
char ret_addr[9] = {0x0};
sprintf(ret_addr, "0x%llx", (long long int)rip);
long long int offset;
char* symbol = (char*)SearchSymbol(ret_addr, &offset);
printf("Faulting instruction at [%018lx] %s (+0x%llx)\n", (uint64_t)rip, symbol, offset);
do{
memset(ret_addr, 0x00, 9);
sprintf(ret_addr, "0x%llx", (long long int) *((uint64_t*)rbp+1));
//printf("ret_addr [%s]\n", ret_addr);
symbol = SearchSymbol(ret_addr, &offset);
if(symbol == NULL)
{
printf("[%018lx] %s (+0x%llx)\n", (uint64_t)*((uint64_t*)rbp+1), "Unknown", (long long unsigned int)0);
break;
}
printf("[%018lx] %s (+0x%llx)\n", (uint64_t)*((uint64_t*)rbp+1), symbol, offset);
rbp = (void*)*((uint64_t*)rbp);
} while( symbol == NULL || strcmp(symbol, "main") != 0);
exit(0); // terminate process
}
// Add symbol with relative address to last module,
// pMT points to the Module Table
int AddSymbol(MODULE_t * MT, char * sym_name, int addr)
{
if (MT == NULL)
return -1; // for safety purpose
SYMBOL_t *pSym = SearchSymbol(MT, sym_name);
if (pSym) // already defined?
{
pSym->flag |= MULTIDEF;
return 0;
}
MODULE_t * pMod = &MT[mod_count-1];
pSym = &(pMod->Def[pMod->def_count++]);
pSym->addr = addr; // initialize new symbol
strcpy(pSym->symbol, sym_name);
pSym->flag = 0x00;
return 0;
}
// Pass Two
void PassTwo(FILE* pFile, MODULE_t * MT)
{
if (!pFile)
{
// file pointer invalid?
printf("File access error, exit.\n");
return;
}
printf("Memory Map\n");
rewind(pFile); // back to the beginning
char instr_type, * instr;
int addr = 0;
int def_count = 0;
int oprand, errno;
char *sym;
SYMBOL_t *pSym;
int i, j;
for (i=0;i<ModuleTableSize();i++)
{
def_count = atoi(GetToken(pFile,NULL,NULL));
SkipToken(pFile, def_count*2+1+MT[i].use_count+1);
for (j=0; j<MT[i].size; j++)
{
instr_type = GetToken(pFile, NULL, NULL)[0];
instr = GetToken(pFile, NULL, NULL);
if (strlen(instr) > 4)
{
if (instr_type == 'I')
PrintInstr(addr, '9', 999, INSTR_ILLEGAL_I, NULL);
else
PrintInstr(addr, '9', 999, INSTR_ILLEGAL_OP, NULL);
}
else
{
oprand = atoi(instr+1); // get oprand regardless if 'I' type instruction
errno = INSTR_NO_ERROR;
sym = NULL;
switch (instr_type)
{
case 'I':
break;
case 'A':
if (oprand > 511)
{
oprand = 0;
errno = INSTR_LARGE_A;
}
break;
case 'R':
if (oprand > MT[i].size)
{
oprand = MT[i].addr;
errno = INSTR_LARGE_R;
}
else
oprand += MT[i].addr;
break;
case 'E':
if (oprand < MT[i].use_count)
{
MT[i].Use[oprand].flag |= REFERRED;
sym = MT[i].Use[oprand].symbol;
pSym = SearchSymbol(MT, sym);
if (pSym == NULL)
{
oprand = 0;
errno = INSTR_NO_DEF;
}
else
{
pSym->flag |= REFERRED;
oprand = pSym->addr;
}
}
else
{
errno = INSTR_LARGE_E;
}
break;
} // switch
PrintInstr(addr, instr[0], oprand, errno, sym);
} // if-else
addr++; // finished one instruction, increment addr
} // for each instruction
UseListCheck(MT, i);
} // for each module
RefCheck(MT);
}
