diff --git a/src/data.rs b/src/data.rs
index 0b3845e..6ad8d8b 100644
--- a/src/data.rs
+++ b/src/data.rs
@@ -1,5 +1,5 @@
 use core::ops::{Deref, DerefMut};
-use core::{mem, slice};
+use core::{fmt, mem, slice};
 
 #[derive(Copy, Clone, Debug, Default)]
 #[repr(C)]
@@ -13,7 +13,7 @@ impl Deref for Event {
     type Target = [u8];
     fn deref(&self) -> &[u8] {
         unsafe {
-            slice::from_raw_parts(self as *const Event as *const u8, mem::size_of::<Event>()) as &[u8]
+            slice::from_raw_parts(self as *const Event as *const u8, mem::size_of::<Event>())
         }
     }
 }
@@ -21,7 +21,7 @@ impl Deref for Event {
 impl DerefMut for Event {
     fn deref_mut(&mut self) -> &mut [u8] {
         unsafe {
-            slice::from_raw_parts_mut(self as *mut Event as *mut u8, mem::size_of::<Event>()) as &mut [u8]
+            slice::from_raw_parts_mut(self as *mut Event as *mut u8, mem::size_of::<Event>())
         }
     }
 }
@@ -38,7 +38,7 @@ impl Deref for ITimerSpec {
     fn deref(&self) -> &[u8] {
         unsafe {
             slice::from_raw_parts(self as *const ITimerSpec as *const u8,
-                                  mem::size_of::<ITimerSpec>()) as &[u8]
+                                  mem::size_of::<ITimerSpec>())
         }
     }
 }
@@ -47,7 +47,7 @@ impl DerefMut for ITimerSpec {
     fn deref_mut(&mut self) -> &mut [u8] {
         unsafe {
             slice::from_raw_parts_mut(self as *mut ITimerSpec as *mut u8,
-                                      mem::size_of::<ITimerSpec>()) as &mut [u8]
+                                      mem::size_of::<ITimerSpec>())
         }
     }
 }
@@ -64,7 +64,7 @@ impl Deref for Map {
     type Target = [u8];
     fn deref(&self) -> &[u8] {
         unsafe {
-            slice::from_raw_parts(self as *const Map as *const u8, mem::size_of::<Map>()) as &[u8]
+            slice::from_raw_parts(self as *const Map as *const u8, mem::size_of::<Map>())
         }
     }
 }
@@ -72,7 +72,7 @@ impl Deref for Map {
 impl DerefMut for Map {
     fn deref_mut(&mut self) -> &mut [u8] {
         unsafe {
-            slice::from_raw_parts_mut(self as *mut Map as *mut u8, mem::size_of::<Map>()) as &mut [u8]
+            slice::from_raw_parts_mut(self as *mut Map as *mut u8, mem::size_of::<Map>())
         }
     }
 }
@@ -94,7 +94,7 @@ impl Deref for Packet {
     type Target = [u8];
     fn deref(&self) -> &[u8] {
         unsafe {
-            slice::from_raw_parts(self as *const Packet as *const u8, mem::size_of::<Packet>()) as &[u8]
+            slice::from_raw_parts(self as *const Packet as *const u8, mem::size_of::<Packet>())
         }
     }
 }
@@ -102,27 +102,26 @@ impl Deref for Packet {
 impl DerefMut for Packet {
     fn deref_mut(&mut self) -> &mut [u8] {
         unsafe {
-            slice::from_raw_parts_mut(self as *mut Packet as *mut u8, mem::size_of::<Packet>()) as &mut [u8]
+            slice::from_raw_parts_mut(self as *mut Packet as *mut u8, mem::size_of::<Packet>())
         }
     }
 }
 
-#[derive(Copy, Clone, Debug)]
+#[derive(Copy, Clone, Debug, Default, PartialEq)]
 #[repr(C)]
 pub struct SigAction {
-    pub sa_handler: extern "C" fn(usize),
+    pub sa_handler: Option<extern "C" fn(usize)>,
     pub sa_mask: [u64; 2],
     pub sa_flags: usize,
 }
 
-impl Default for SigAction {
-    fn default() -> Self {
-        Self {
-            sa_handler: unsafe { mem::transmute(0usize) },
-            sa_mask: [0; 2],
-            sa_flags: 0,
-        }
-    }
+#[allow(dead_code)]
+unsafe fn _assert_size_of_function_is_sane() {
+    // Transmuting will complain *at compile time* if sizes differ.
+    // Rust forbids a fn-pointer from being 0 so to allow SIG_DFL to
+    // exist, we use Option<extern "C" fn(usize)> which will mean 0
+    // becomes None
+    let _ = mem::transmute::<Option<extern "C" fn(usize)>, usize>(None);
 }
 
 #[derive(Copy, Clone, Debug, Default, PartialEq)]
@@ -150,7 +149,7 @@ impl Deref for Stat {
     fn deref(&self) -> &[u8] {
         unsafe {
             slice::from_raw_parts(self as *const Stat as *const u8,
-                                  mem::size_of::<Stat>()) as &[u8]
+                                  mem::size_of::<Stat>())
         }
     }
 }
@@ -159,7 +158,7 @@ impl DerefMut for Stat {
     fn deref_mut(&mut self) -> &mut [u8] {
         unsafe {
             slice::from_raw_parts_mut(self as *mut Stat as *mut u8,
-                                      mem::size_of::<Stat>()) as &mut [u8]
+                                      mem::size_of::<Stat>())
         }
     }
 }
@@ -178,7 +177,7 @@ impl Deref for StatVfs {
     fn deref(&self) -> &[u8] {
         unsafe {
             slice::from_raw_parts(self as *const StatVfs as *const u8,
-                                  mem::size_of::<StatVfs>()) as &[u8]
+                                  mem::size_of::<StatVfs>())
         }
     }
 }
@@ -187,7 +186,7 @@ impl DerefMut for StatVfs {
     fn deref_mut(&mut self) -> &mut [u8] {
         unsafe {
             slice::from_raw_parts_mut(self as *mut StatVfs as *mut u8,
-                                      mem::size_of::<StatVfs>()) as &mut [u8]
+                                      mem::size_of::<StatVfs>())
         }
     }
 }
@@ -204,7 +203,7 @@ impl Deref for TimeSpec {
     fn deref(&self) -> &[u8] {
         unsafe {
             slice::from_raw_parts(self as *const TimeSpec as *const u8,
-                                  mem::size_of::<TimeSpec>()) as &[u8]
+                                  mem::size_of::<TimeSpec>())
         }
     }
 }
@@ -213,7 +212,7 @@ impl DerefMut for TimeSpec {
     fn deref_mut(&mut self) -> &mut [u8] {
         unsafe {
             slice::from_raw_parts_mut(self as *mut TimeSpec as *mut u8,
-                                      mem::size_of::<TimeSpec>()) as &mut [u8]
+                                      mem::size_of::<TimeSpec>())
         }
     }
 }
@@ -257,7 +256,7 @@ impl Deref for IntRegisters {
     type Target = [u8];
     fn deref(&self) -> &[u8] {
         unsafe {
-            slice::from_raw_parts(self as *const IntRegisters as *const u8, mem::size_of::<IntRegisters>()) as &[u8]
+            slice::from_raw_parts(self as *const IntRegisters as *const u8, mem::size_of::<IntRegisters>())
         }
     }
 }
@@ -265,7 +264,7 @@ impl Deref for IntRegisters {
 impl DerefMut for IntRegisters {
     fn deref_mut(&mut self) -> &mut [u8] {
         unsafe {
-            slice::from_raw_parts_mut(self as *mut IntRegisters as *mut u8, mem::size_of::<IntRegisters>()) as &mut [u8]
+            slice::from_raw_parts_mut(self as *mut IntRegisters as *mut u8, mem::size_of::<IntRegisters>())
         }
     }
 }
@@ -291,7 +290,7 @@ impl Deref for FloatRegisters {
     type Target = [u8];
     fn deref(&self) -> &[u8] {
         unsafe {
-            slice::from_raw_parts(self as *const FloatRegisters as *const u8, mem::size_of::<FloatRegisters>()) as &[u8]
+            slice::from_raw_parts(self as *const FloatRegisters as *const u8, mem::size_of::<FloatRegisters>())
         }
     }
 }
@@ -299,7 +298,52 @@ impl Deref for FloatRegisters {
 impl DerefMut for FloatRegisters {
     fn deref_mut(&mut self) -> &mut [u8] {
         unsafe {
-            slice::from_raw_parts_mut(self as *mut FloatRegisters as *mut u8, mem::size_of::<FloatRegisters>()) as &mut [u8]
+            slice::from_raw_parts_mut(self as *mut FloatRegisters as *mut u8, mem::size_of::<FloatRegisters>())
+        }
+    }
+}
+
+#[derive(Clone, Copy)]
+#[repr(C)]
+pub union PtraceEventData {
+    pub clone: usize,
+    pub signal: usize
+}
+
+impl Default for PtraceEventData {
+    fn default() -> Self {
+        Self {
+            clone: 0,
+        }
+    }
+}
+
+impl fmt::Debug for PtraceEventData {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "PtraceEventData(...)")
+    }
+}
+
+#[derive(Clone, Copy, Debug, Default)]
+#[repr(C)]
+pub struct PtraceEvent {
+    pub tag: u16,
+    pub data: PtraceEventData,
+}
+
+impl Deref for PtraceEvent {
+    type Target = [u8];
+    fn deref(&self) -> &[u8] {
+        unsafe {
+            slice::from_raw_parts(self as *const PtraceEvent as *const u8, mem::size_of::<PtraceEvent>())
+        }
+    }
+}
+
+impl DerefMut for PtraceEvent {
+    fn deref_mut(&mut self) -> &mut [u8] {
+        unsafe {
+            slice::from_raw_parts_mut(self as *mut PtraceEvent as *mut u8, mem::size_of::<PtraceEvent>())
         }
     }
 }
diff --git a/src/flag.rs b/src/flag.rs
index e6c4cbf..9c928b4 100644
--- a/src/flag.rs
+++ b/src/flag.rs
@@ -69,9 +69,14 @@ pub const PTRACE_CONT: u8 = 0b0000_0001;
 pub const PTRACE_SINGLESTEP: u8 = 0b0000_0010;
 pub const PTRACE_SYSCALL: u8 = 0b0000_0011;
 pub const PTRACE_WAIT: u8 = 0b0000_0100;
+pub const PTRACE_SIGNAL: u8 = 0b0000_0101;
+
 pub const PTRACE_OPERATIONMASK: u8 = 0b0000_1111;
 pub const PTRACE_SYSEMU: u8 = 0b0001_0000;
 
+pub const PTRACE_EVENT_CLONE: u16 = 0;
+pub const PTRACE_EVENT_SIGNAL: u16 = 1;
+
 pub const SEEK_SET: usize = 0;
 pub const SEEK_CUR: usize = 1;
 pub const SEEK_END: usize = 2;
diff --git a/src/tests.rs b/src/tests.rs
index 03273d4..7dd2bad 100644
--- a/src/tests.rs
+++ b/src/tests.rs
@@ -409,3 +409,68 @@ fn unlink() {
 fn sched_yield() {
     assert_eq!(dbg!(crate::sched_yield()), Ok(0));
 }
+
+#[test]
+fn sigaction() {
+    use std::{
+        mem,
+        sync::atomic::{AtomicBool, Ordering}
+    };
+
+    static SA_HANDLER_WAS_RAN: AtomicBool = AtomicBool::new(false);
+    static SA_HANDLER_2_WAS_IGNORED: AtomicBool = AtomicBool::new(false);
+
+    let child = unsafe { crate::clone(crate::CLONE_VM).unwrap() };
+
+    if child == 0 {
+        let pid = crate::getpid().unwrap();
+
+        extern "C" fn hello_im_a_signal_handler(signal: usize) {
+            assert_eq!(signal, crate::SIGUSR1);
+            SA_HANDLER_WAS_RAN.store(true, Ordering::SeqCst);
+        }
+
+        let my_signal_handler = crate::SigAction {
+            sa_handler: Some(hello_im_a_signal_handler),
+            ..Default::default()
+        };
+        crate::sigaction(crate::SIGUSR1, Some(&my_signal_handler), None).unwrap();
+
+        crate::kill(pid, crate::SIGUSR1).unwrap(); // calls handler
+
+        let mut old_signal_handler = crate::SigAction::default();
+        crate::sigaction(
+            crate::SIGUSR1,
+            Some(&crate::SigAction {
+                sa_handler: unsafe { mem::transmute::<usize, Option<extern "C" fn(usize)>>(crate::SIG_IGN) },
+                ..Default::default()
+            }),
+            Some(&mut old_signal_handler)
+        ).unwrap();
+        assert_eq!(my_signal_handler, old_signal_handler);
+
+        crate::kill(pid, crate::SIGUSR1).unwrap(); // does nothing
+
+        SA_HANDLER_2_WAS_IGNORED.store(true, Ordering::SeqCst);
+
+        crate::sigaction(
+            crate::SIGUSR1,
+            Some(&crate::SigAction {
+                sa_handler: unsafe { mem::transmute::<usize, Option<extern "C" fn(usize)>>(crate::SIG_DFL) },
+                ..Default::default()
+            }),
+            Some(&mut old_signal_handler)
+        ).unwrap();
+
+        crate::kill(pid, crate::SIGUSR1).unwrap(); // actually exits
+    } else {
+        let mut status = 0;
+        dbg!(crate::waitpid(child, &mut status, 0)).unwrap();
+
+        assert!(crate::wifsignaled(status));
+        assert_eq!(crate::wtermsig(status), crate::SIGUSR1);
+
+        assert!(SA_HANDLER_WAS_RAN.load(Ordering::SeqCst));
+        assert!(SA_HANDLER_2_WAS_IGNORED.load(Ordering::SeqCst));
+    }
+}