Fix: custom signal handler not working

kernel/lib/process.c

@@ -108,6 +108,8 @@ process_t *fork_process(const process_t *from)
   process_t *ret = _make_process();
   memcpy(ret->stack, from->stack, from->stack_size);
   memcpy(ret->mem, from->mem, from->mem_size);
+  memcpy(ret->sigstack, from->sigstack, from->sigstack_size);
+  memcpy(ret->sighandlers, from->sighandlers, sizeof(from->sighandlers));
   *ret->regs = (trapframe_t){
     .x0 = 0, // fork return value
     .fp = from->regs->fp - (uint64_t)from->stack + (uint64_t)ret->stack,