From d61b878d03c3381a839f49578a6939e6e4e188d4 Mon Sep 17 00:00:00 2001
From: vasilito <adminpupkin@gmail.com>
Date: Fri, 17 Jul 2026 18:13:54 +0900
Subject: [PATCH] =?UTF-8?q?sessiond:=20syscall-level=20DIAG=20=E2=80=94=20?=
 =?UTF-8?q?register=20pipe=20vs=20uds=5Fstream=20fd=20with=20/scheme/event?=
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---
 .../redbear-sessiond/source/src/main.rs       | 55 ++++++++++++++-----
 1 file changed, 42 insertions(+), 13 deletions(-)

diff --git a/local/recipes/system/redbear-sessiond/source/src/main.rs b/local/recipes/system/redbear-sessiond/source/src/main.rs
index 420a98f43f..f68ba1f1da 100644
--- a/local/recipes/system/redbear-sessiond/source/src/main.rs
+++ b/local/recipes/system/redbear-sessiond/source/src/main.rs
@@ -224,21 +224,50 @@ fn main() {
             println!("{}", usage());
         }
         Ok(Command::Run) => {
-            // SESSIOND_DIAG (temporary): pinpoint which tokio runtime config
-            // EINVALs on Redox. Each line shows in the boot console.
-            macro_rules! diag {
-                ($label:expr, $build:expr) => {
-                    match $build {
-                        Ok(rt) => { eprintln!("SESSIOND_DIAG: {} OK", $label); drop(rt); }
-                        Err(e) => eprintln!("SESSIOND_DIAG: {} FAIL {}", $label, e),
+            // SESSIOND_DIAG (temporary): the I/O reactor (enable_all) EINVALs.
+            // Confirm whether registering an ipcd uds_stream fd (used by tokio's
+            // signal-driver receiver) with /scheme/event is what fails, vs a
+            // kernel pipe fd (used by the mio waker, which should succeed).
+            {
+                use std::os::fd::AsRawFd;
+                use syscall::data::Event;
+                use syscall::flag::EventFlags;
+                const O_RDWR_S: i32 = 0x0003_0000;
+                const O_RDONLY_S: i32 = 0x0001_0000;
+                fn register(epfd: usize, fd: usize) -> syscall::Result<usize> {
+                    let ev = Event { id: fd, flags: EventFlags::EVENT_READ, data: 0 };
+                    let bytes = unsafe {
+                        core::slice::from_raw_parts(
+                            (&ev as *const Event) as *const u8,
+                            core::mem::size_of::<Event>(),
+                        )
+                    };
+                    syscall::write(epfd, bytes)
+                }
+                match libredox::call::open("/scheme/event", O_RDWR_S, 0) {
+                    Ok(epfd) => {
+                        eprintln!("SESSIOND_DIAG: open /scheme/event OK");
+                        match libredox::call::open("/scheme/pipe", O_RDONLY_S, 0) {
+                            Ok(pfd) => {
+                                eprintln!("SESSIOND_DIAG: register PIPE fd = {:?}", register(epfd, pfd));
+                                let _ = libredox::call::close(pfd);
+                            }
+                            Err(e) => eprintln!("SESSIOND_DIAG: open /scheme/pipe FAIL {:?}", e),
+                        }
+                        match std::os::unix::net::UnixStream::pair() {
+                            Ok((a, _b)) => {
+                                eprintln!(
+                                    "SESSIOND_DIAG: register UDS_STREAM fd = {:?}",
+                                    register(epfd, a.as_raw_fd() as usize)
+                                );
+                            }
+                            Err(e) => eprintln!("SESSIOND_DIAG: UnixStream::pair FAIL {}", e),
+                        }
+                        let _ = libredox::call::close(epfd);
                     }
-                };
+                    Err(e) => eprintln!("SESSIOND_DIAG: open /scheme/event FAIL {:?}", e),
+                }
             }
-            diag!("ct-none", RuntimeBuilder::new_current_thread().build());
-            diag!("ct-time", RuntimeBuilder::new_current_thread().enable_time().build());
-            diag!("ct-all", RuntimeBuilder::new_current_thread().enable_all().build());
-            diag!("mt-none", RuntimeBuilder::new_multi_thread().build());
-            diag!("mt-all", RuntimeBuilder::new_multi_thread().enable_all().build());
 
             let runtime = match RuntimeBuilder::new_multi_thread().enable_all().build() {
                 Ok(runtime) => runtime,