From f4d643e87c1815f16190b643a92494541e245b8a Mon Sep 17 00:00:00 2001
From: 4lDO2 <4lDO2@protonmail.com>
Date: Thu, 10 Apr 2025 21:03:25 +0200
Subject: [PATCH] Fixes for netstack cancellation to work.

---
 src/scheme/user.rs | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/src/scheme/user.rs b/src/scheme/user.rs
index 5f1ee257f4..cd90436f2f 100644
--- a/src/scheme/user.rs
+++ b/src/scheme/user.rs
@@ -303,9 +303,9 @@ impl UserInner {
                 // the caller is interrupted by SIGKILL.
                 callee_responsible: PageSpan::empty(),
             };
+            self.todo.send(sqe);
         }
 
-        self.todo.send(sqe);
         event::trigger(self.root_id, self.handle_id, EVENT_READ);
 
         loop {
@@ -830,7 +830,7 @@ impl UserInner {
                     return Ok(Packet {
                         id: 0,
                         a: KSMSG_CANCEL,
-                        b: sqe.tag as usize,
+                        b: sqe.tag as usize + 1,
                         c: 0,
                         d: 0,
                         pid: sqe.caller as usize,
@@ -1061,15 +1061,23 @@ impl UserInner {
                     canceling,
                     callee_responsible,
                 } => {
+                    // Convert ECANCELED to EINTR if a request was being canceled (currently always
+                    // due to signals).
+                    if let Response::Regular(ref mut code, _) = response
+                        && canceling
+                        && *code == Error::mux(Err(Error::new(ECANCELED)))
+                    {
+                        *code = Error::mux(Err(Error::new(EINTR)));
+                    }
+
+                    // TODO: Require ECANCELED?
                     if let Response::Regular(ref mut code, _) = response
                         && !canceling
                         && *code == Error::mux(Err(Error::new(EINTR)))
                     {
                         // EINTR is valid after cancelation has been requested, but not otherwise.
-                        // This is because the kernel-assisted signal trampoline will be invoked
-                        // after a syscall returns EINTR.
-                        //
-                        // TODO: Reserve another error code for user-caused vs kernel-caused EINTR?
+                        // This is because the userspace signal trampoline will be invoked after a
+                        // syscall returns EINTR.
                         *code = Error::mux(Err(Error::new(EIO)));
                     }