From 59054bd46672d0de1777be3566da244f611774d0 Mon Sep 17 00:00:00 2001
From: Koute <koute@users.noreply.github.com>
Date: Mon, 17 Apr 2023 15:44:08 +0900
Subject: [PATCH] Use `MaybeUninit` when calling `getrusage` (musl
 compatibility) (#7086)

---
 .../node/core/pvf/src/prepare/memory_stats.rs | 30 ++++++-------------
 1 file changed, 9 insertions(+), 21 deletions(-)

diff --git a/polkadot/node/core/pvf/src/prepare/memory_stats.rs b/polkadot/node/core/pvf/src/prepare/memory_stats.rs
index 069ef46cab..3513a68c79 100644
--- a/polkadot/node/core/pvf/src/prepare/memory_stats.rs
+++ b/polkadot/node/core/pvf/src/prepare/memory_stats.rs
@@ -197,33 +197,21 @@ pub mod memory_tracker {
 #[cfg(target_os = "linux")]
 pub mod max_rss_stat {
 	use crate::LOG_TARGET;
-	use libc::{getrusage, rusage, timeval, RUSAGE_THREAD};
+	use core::mem::MaybeUninit;
+	use libc::{getrusage, rusage, RUSAGE_THREAD};
 	use std::io;
 
 	/// Get the rusage stats for the current thread.
 	fn getrusage_thread() -> io::Result<rusage> {
-		let mut result = rusage {
-			ru_utime: timeval { tv_sec: 0, tv_usec: 0 },
-			ru_stime: timeval { tv_sec: 0, tv_usec: 0 },
-			ru_maxrss: 0,
-			ru_ixrss: 0,
-			ru_idrss: 0,
-			ru_isrss: 0,
-			ru_minflt: 0,
-			ru_majflt: 0,
-			ru_nswap: 0,
-			ru_inblock: 0,
-			ru_oublock: 0,
-			ru_msgsnd: 0,
-			ru_msgrcv: 0,
-			ru_nsignals: 0,
-			ru_nvcsw: 0,
-			ru_nivcsw: 0,
-		};
-		if unsafe { getrusage(RUSAGE_THREAD, &mut result) } == -1 {
+		let mut result: MaybeUninit<rusage> = MaybeUninit::zeroed();
+
+		// SAFETY: `result` is a valid pointer, so calling this is safe.
+		if unsafe { getrusage(RUSAGE_THREAD, result.as_mut_ptr()) } == -1 {
 			return Err(io::Error::last_os_error())
 		}
-		Ok(result)
+
+		// SAFETY: `result` was successfully initialized by `getrusage`.
+		unsafe { Ok(result.assume_init()) }
 	}
 
 	/// Gets the `ru_maxrss` for the current thread.