// Common function to handle all system calls -
// decode the system call type and call an appropriate handler function.
// Be sure to handle undefined system calls appropriately.
void
syscall(trapframe *tf)
{
// EAX register holds system call command/flags
uint32_t cmd = tf->regs.eax;
switch (cmd & SYS_TYPE) {
case SYS_CPUTS: return do_cputs(tf, cmd);
case SYS_PUT: return do_put(tf, cmd);
case SYS_GET: return do_get(tf, cmd);
case SYS_RET: return do_ret(tf, cmd);
default: return; // handle as a regular trap
}
}
void parser()
{
int ab_code=4, x=line_ndx;
int I;
switch(token)
{
case 0:
break;
case 1:
parse_let();
break;
case 2:
cls();
break;
case 3:
locate();
break;
case 4:
xstring_array();
get_prnstring();
break;
case 5:
go_to();
break;
case 6:
beep();
break;
case 7:
cls();
break;
case 8:
line_ndx = nrows;
break;
case 9:
do_gs();
break;
case 10:
do_ret();
break;
case 11:
do_loop();
break;
case 12:
do_next();
break;
case 13:
do_iloop();
break;
case 14:
do_iloop();
break;
case 15:
return;
break;
case 16:
return;
break;
case -1:
break;
default:
printf("parser Inside DEFAULT\n");
printf("p_string = %s\n",p_string);
a_bort(ab_code, x);
break;
}
}
byte * _f_handler_inst_retn(byte * inst) {
log_data("RETN reached");
do_ret(RADDR(inst),1);
return 0;
}
byte * _f_handler_inst_gen_1op(byte * inst) {
dword rtype, arg1, arg2;
MODREGDEC(inst+1,arg1,arg2,rtype);
dword target;
it_inner_entry *it;
/* TODO embbed this on the mphash */
switch (arg2) {
case INST_GEN_CALL:
if (rtype == smod_reg_RR) {
flux_staple(RADDR(inst),2);
return inst+2;
}
target = *(dword*)(inst+2);
log_debug("CALL to %X",target);
if (!is_code(target,&it)) {
if (it) {
/* maybe examine here the arguments for ease of analysis? */
log_debug("External function (%s) (%s)",it->name,it->libname);
if (!strcmp("ExitProcess",it->name)) {
/* its an exit process, function ends here */
do_ret(RADDR(inst),6);
log_debug("exit function reached");
return 0;
}
}
}
else {
//return (byte*)target;
/* queue function for analysis */
}
flux_staple(RADDR(inst),6);
return inst+6;
case INST_GEN_JMP:
target = *(dword*)(inst+2);
it_inner_entry * it;
if (!is_code(target,&it)) {
log_debug("JMP to outside, assuming ret");
/* this is used normally to call external functions in a relloc fashion,
assume RET here */
do_ret(RADDR(inst),6);
return 0;
}
else {
}
flux_staple(RADDR(inst),6);
return inst+6;
case INST_GEN_JMPF:
/* jmp far, let's check the target */
break;
case INST_GEN_INC:
case INST_GEN_DEC:
case INST_GEN_CALLF:
/* this is a register call, we must flag it, but we cannot know what was called right now */
case INST_GEN_PUSH:
if (rtype == smod_reg_IR) {
if (arg1 == mod_reg_EBP) {
/* not really ebp here, but disp32 */
flux_staple(RADDR(inst),6);
return inst+6;
}
if (arg1 == mod_reg_SIB) {
MODREGDEC(inst+2,arg1,arg2,rtype);
flux_staple(RADDR(inst),7);
return inst+7;
}
flux_staple(RADDR(inst),2);
return inst+2;
}
if (rtype == smod_reg_I8R) {
flux_staple(RADDR(inst),3);
return inst+3;
}
if (rtype == smod_reg_RR) {
flux_staple(RADDR(inst),2);
return inst+2;
}
flux_staple(RADDR(inst),6);
return inst+6;
break;
}
return inst;
}