From 587d15054440084fd1cfc07ca55d3f2daea5592b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=90=D0=B7=D0=B0=D0=BB=D0=B8=D1=8F=20=D0=A1=D0=BC=D0=B0?=
 =?UTF-8?q?=D1=80=D0=B0=D0=B3=D0=B4=D0=BE=D0=B2=D0=B0?=
 <charming.flurry@yandex.ru>
Date: Sat, 15 Jun 2024 18:20:39 +0500
Subject: [PATCH 1/3] Add sigaction() versions that allow specify the signal by
 its number (to allow working with real-time signals) and replace the signal
 handler without retrieving the old one.

---
 src/sys/signal.rs | 50 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/src/sys/signal.rs b/src/sys/signal.rs
index abf6f21abf..97dd85a9b1 100644
--- a/src/sys/signal.rs
+++ b/src/sys/signal.rs
@@ -901,6 +901,56 @@ pub unsafe fn sigaction(signal: Signal, sigaction: &SigAction) -> Result<SigActi
     Errno::result(res).map(|_| SigAction { sigaction: unsafe { oldact.assume_init() } })
 }
 
+/// Changes the action taken by a process on receipt of a specific signal, which is specified by a signal number.
+///
+/// `signal` can be any signal except `SIGKILL` or `SIGSTOP`. On success, it returns the previous
+/// action for the given signal. If `sigaction` fails, no new signal handler is installed.
+///
+/// # Safety
+///
+/// * Signal handlers may be called at any point during execution, which limits
+///   what is safe to do in the body of the signal-catching function. Be certain
+///   to only make syscalls that are explicitly marked safe for signal handlers
+///   and only share global data using atomics.
+///
+/// * There is also no guarantee that the old signal handler was installed
+///   correctly.  If it was installed by this crate, it will be.  But if it was
+///   installed by, for example, C code, then there is no guarantee its function
+///   pointer is valid.  In that case, this function effectively dereferences a
+///   raw pointer of unknown provenance.
+pub unsafe fn sigaction_numeric(signal: libc::c_int, sigaction: &SigAction) -> Result<SigAction> {
+    let mut oldact = mem::MaybeUninit::<libc::sigaction>::uninit();
+
+    let res = unsafe { libc::sigaction(signal as libc::c_int,
+                              &sigaction.sigaction as *const libc::sigaction,
+                              oldact.as_mut_ptr()) };
+
+    Errno::result(res).map(|_| SigAction { sigaction: unsafe { oldact.assume_init() } })
+}
+
+/// Changes the action taken by a process on receipt of a specific signal, which is specified by a signal number. Old sigaction struct is not retrieved.
+///
+/// `signal` can be any signal except `SIGKILL` or `SIGSTOP`. On success, it returns the previous
+/// action for the given signal. If `sigaction` fails, no new signal handler is installed.
+///
+/// # Safety
+///
+/// * Signal handlers may be called at any point during execution, which limits
+///   what is safe to do in the body of the signal-catching function. Be certain
+///   to only make syscalls that are explicitly marked safe for signal handlers
+///   and only share global data using atomics.
+pub unsafe fn sigaction_noretrieve(signal: libc::c_int, sigaction: &SigAction) -> Result<()> {
+    let res = unsafe { libc::sigaction(signal as libc::c_int,
+                              &sigaction.sigaction as *const libc::sigaction,
+                              std::ptr::null_mut()) };
+
+    match Errno::result(res) {
+       Ok(_) => { return Ok(()); }
+       Err(e) => { return Err(e); }
+    }
+    
+}
+
 /// Signal management (see [signal(3p)](https://pubs.opengroup.org/onlinepubs/9699919799/functions/signal.html))
 ///
 /// Installs `handler` for the given `signal`, returning the previous signal

From cc7c8345423e8da19027d58dd5dc917c10d1bae7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=90=D0=B7=D0=B0=D0=BB=D0=B8=D1=8F=20=D0=A1=D0=BC=D0=B0?=
 =?UTF-8?q?=D1=80=D0=B0=D0=B3=D0=B4=D0=BE=D0=B2=D0=B0?=
 <charming.flurry@yandex.ru>
Date: Sat, 15 Jun 2024 19:29:08 +0500
Subject: [PATCH 2/3] Fix return value of
 nix::sys::signal::sigaction_noretrieve()

---
 src/sys/signal.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/sys/signal.rs b/src/sys/signal.rs
index 97dd85a9b1..023316c15a 100644
--- a/src/sys/signal.rs
+++ b/src/sys/signal.rs
@@ -945,8 +945,8 @@ pub unsafe fn sigaction_noretrieve(signal: libc::c_int, sigaction: &SigAction) -
                               std::ptr::null_mut()) };
 
     match Errno::result(res) {
-       Ok(_) => { return Ok(()); }
-       Err(e) => { return Err(e); }
+       Ok(_) => { Ok(()) }
+       Err(e) => { Err(e) }
     }
     
 }

From 01a10675fd94084a0e498bf8c8c68586b1a84d92 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=90=D0=B7=D0=B0=D0=BB=D0=B8=D1=8F=20=D0=A1=D0=BC=D0=B0?=
 =?UTF-8?q?=D1=80=D0=B0=D0=B3=D0=B4=D0=BE=D0=B2=D0=B0?=
 <charming.flurry@yandex.ru>
Date: Sat, 15 Jun 2024 19:49:09 +0500
Subject: [PATCH 3/3] cargo fmt

---
 src/sys/signal.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/sys/signal.rs b/src/sys/signal.rs
index 023316c15a..586e4240e4 100644
--- a/src/sys/signal.rs
+++ b/src/sys/signal.rs
@@ -948,7 +948,7 @@ pub unsafe fn sigaction_noretrieve(signal: libc::c_int, sigaction: &SigAction) -
        Ok(_) => { Ok(()) }
        Err(e) => { Err(e) }
     }
-    
+
 }
 
 /// Signal management (see [signal(3p)](https://pubs.opengroup.org/onlinepubs/9699919799/functions/signal.html))