From a99c708d0cf030513c2b2596724b270caafeb799 Mon Sep 17 00:00:00 2001
From: namilsk <namilsk@namilsk.tech>
Date: Mon, 12 Jan 2026 21:06:06 +0300
Subject: Rewrited `SIGCHLD handler & updated nix-shell for usage with `musl`
 target

---
 init/src/signals/sigchld.rs | 62 +++++++++++++++++++++++++++------------------
 1 file changed, 37 insertions(+), 25 deletions(-)

(limited to 'init/src')

diff --git a/init/src/signals/sigchld.rs b/init/src/signals/sigchld.rs
index a55a00a..a02b82f 100644
--- a/init/src/signals/sigchld.rs
+++ b/init/src/signals/sigchld.rs
@@ -1,38 +1,50 @@
-use libc::{pid_t, 
-           SIGCHLD, 
-           waitpid, 
-           WNOHANG, 
-           sigaction, 
-           sigemptyset,  
-           SA_RESTART};
+use libc::{c_int, sigaction, siginfo_t, sigset_t, waitpid, SA_RESTART, SA_SIGINFO, SIGCHLD, WNOHANG};
+use std::os::raw::c_void;
 
-use std::ffi::c_int; 
+// extern "C" because:  
+// https://doc.rust-lang.org/reference/items/external-blocks.html?spm=a2ty_o01.29997173.0.0.63e251718NCvPc#abi
+// Doc comments needed...
+extern "C" fn sigchld_handler(
+    _signal: c_int,
+    _info: *mut siginfo_t,
+    _context: *mut c_void,
+) {
+    let saved_errno = unsafe { *libc::__errno_location() };
 
-fn sigchild_handler(_signal: c_int) {
     loop {
-        let mut status: c_int = 0; 
-        let pid: pid_t = unsafe {
-            waitpid(-1 , &mut status, WNOHANG)
-        }; 
+        let mut status: c_int = 0;
+        let pid = unsafe { waitpid(-1, &mut status as *mut c_int, WNOHANG) };
 
-        if pid <= 0 {
-            break; 
+        match pid {
+            0 => break, 
+            -1 => {
+                let errno = unsafe { *libc::__errno_location() };
+                if errno == libc::ECHILD {
+                    break;
+                }
+            }
+            _ => {
+                /* If it doesnt work, ill add the logging here */
+            }
         }
     }
 
+    unsafe { *libc::__errno_location() = saved_errno };
 }
 
-pub fn setup_sigchild_handler() -> Result<(), Box<dyn std::error::Error>> {
+pub fn setup_sigchld_handler() -> Result<(), Box<dyn std::error::Error>> {
     unsafe {
-        let mut sigact: sigaction = std::mem::zeroed(); 
-        sigact.sa_sigaction = sigchild_handler as usize; 
-        sigemptyset(&mut sigact.sa_mask); 
-        sigact.sa_flags = SA_RESTART; 
+        let mut sigact: sigaction = std::mem::zeroed();
+        
+        sigact.sa_sigaction = sigchld_handler as usize;
+        sigact.sa_flags = SA_RESTART | SA_SIGINFO;
+        
+        libc::sigemptyset(&mut sigact.sa_mask as *mut sigset_t);
+        libc::sigaddset(&mut sigact.sa_mask as *mut sigset_t, SIGCHLD);
 
-        if sigaction(SIGCHLD, &sigact, std::ptr::null_mut()) == -1 {
-            Err("Sigaction check returned -1".into())
-        } else { 
-            Ok(()) 
+        if libc::sigaction(SIGCHLD, &sigact, std::ptr::null_mut()) == -1 {
+            return Err("Failed to set SIGCHLD handler".into());
         }
     }
-} 
+    Ok(())
+}
-- 
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