feature: basic signal handling

libusr/src/lib.rs

@@ -10,9 +10,20 @@ pub mod os;
 pub mod sys {
     pub use syscall::calls::*;
     pub use syscall::stat::*;
+    pub use syscall::signal::Signal;
     pub use syscall::termios;
 }
 
+#[inline(never)]
+extern "C" fn _signal_handler(arg: sys::Signal) -> ! {
+    trace!("Entered signal handler: arg={:?}", arg);
+    unsafe {
+        sys::sys_ex_sigreturn();
+    }
+}
+
+static mut SIGNAL_STACK: [u8; 4096] = [0; 4096];
+
 #[link_section = ".text._start"]
 #[no_mangle]
 extern "C" fn _start(_arg: usize) -> ! {
@@ -20,6 +31,9 @@ extern "C" fn _start(_arg: usize) -> ! {
         fn main() -> i32;
     }
     unsafe {
+        SIGNAL_STACK[0] = 1;
+        sys::sys_ex_signal(_signal_handler as usize, SIGNAL_STACK.as_ptr() as usize + 4096);
+
         sys::sys_exit(main());
     }
 }