From a1937f438ca6ea0ff4edc7ea78000a50b2fd1de5 Mon Sep 17 00:00:00 2001
From: 4lDO2 <4lDO2@protonmail.com>
Date: Thu, 17 Apr 2025 12:03:59 +0200
Subject: [PATCH] Allow read-only sigaction for SIG{KILL,STOP}.

---
 redox-rt/src/signal.rs | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/redox-rt/src/signal.rs b/redox-rt/src/signal.rs
index 175a973e21..ae8af97fc1 100644
--- a/redox-rt/src/signal.rs
+++ b/redox-rt/src/signal.rs
@@ -397,8 +397,23 @@ fn convert_old(action: &RawAction) -> Sigaction {
 }
 
 pub fn sigaction(signal: u8, new: Option<&Sigaction>, old: Option<&mut Sigaction>) -> Result<()> {
-    if matches!(usize::from(signal), 0 | 32 | SIGKILL | SIGSTOP | 65..) {
+    if matches!(usize::from(signal), 0 | 32 | 65..) {
         return Err(Error::new(EINVAL));
+
+    }
+    if matches!(usize::from(signal), SIGKILL | SIGSTOP) {
+        if new.is_some() {
+            return Err(Error::new(EINVAL));
+        }
+        if let Some(old) = old {
+            // TODO: Is this the correct value to set it to?
+            *old = Sigaction {
+                kind: SigactionKind::Default,
+                mask: 0,
+                flags: SigactionFlags::empty(),
+            };
+        }
+        return Ok(());
     }
 
     let _sigguard = tmp_disable_signals();