simplify pthread error handling

Author: lovasoa

src/backends/mod.rs

@@ -14,7 +14,6 @@ cfg_if! {
         target_os = "illumos"
     ))] {
         mod unix;
-        mod unix_pthread_wrapper;
         pub use unix::guess_os_stack_limit;
     } else if #[cfg(target_os = "openbsd")] {
         mod openbsd;

src/backends/unix.rs

@@ -1,5 +1,3 @@
-use super::unix_pthread_wrapper::PthreadAttr;
-
 #[cfg(any(target_os = "freebsd", target_os = "dragonfly", target_os = "illumos"))]
 use libc::pthread_attr_get_np as get_attr;
 #[cfg(any(target_os = "linux", target_os = "solaris", target_os = "netbsd"))]
@@ -8,13 +6,53 @@ use libc::pthread_getattr_np as get_attr;
 pub unsafe fn guess_os_stack_limit() -> Option<usize> {
     let mut attr = PthreadAttr::new()?;
 
-    let res = get_attr(libc::pthread_self(), attr.as_mut_ptr());
-    attr.handle_pthread_err(res)?;
+    handle_pthread_err(get_attr(libc::pthread_self(), attr.as_mut_ptr()))?;
 
     let mut stackaddr = std::ptr::null_mut();
     let mut stacksize = 0;
-    let res = libc::pthread_attr_getstack(attr.as_mut_ptr(), &mut stackaddr, &mut stacksize);
-    attr.handle_pthread_err(res)?;
+    handle_pthread_err(libc::pthread_attr_getstack(
+        attr.as_mut_ptr(),
+        &mut stackaddr,
+        &mut stacksize,
+    ))?;
 
     Some(stackaddr as usize)
 }
+
+struct PthreadAttr(std::mem::MaybeUninit<libc::pthread_attr_t>);
+
+impl Drop for PthreadAttr {
+    fn drop(&mut self) {
+        unsafe {
+            let ret = libc::pthread_attr_destroy(self.0.as_mut_ptr());
+            if ret != 0 {
+                let err = std::io::Error::last_os_error();
+                panic!(
+                    "pthread_attr_destroy failed with error code {}: {}",
+                    ret, err
+                );
+            }
+        }
+    }
+}
+
+fn handle_pthread_err(ret: libc::c_int) -> Option<()> {
+    if ret != 0 {
+        return None;
+    }
+    Some(())
+}
+
+impl PthreadAttr {
+    unsafe fn new() -> Option<Self> {
+        let mut attr = std::mem::MaybeUninit::<libc::pthread_attr_t>::uninit();
+        if libc::pthread_attr_init(attr.as_mut_ptr()) != 0 {
+            return None;
+        }
+        Some(PthreadAttr(attr))
+    }
+
+    fn as_mut_ptr(&mut self) -> *mut libc::pthread_attr_t {
+        self.0.as_mut_ptr()
+    }
+}