diff --git a/src/common.rs b/src/common.rs
index 698e524b1..f98548dc1 100644
--- a/src/common.rs
+++ b/src/common.rs
@@ -1184,15 +1184,12 @@ pub fn truncate_at_nul(input: &wstr) -> &wstr {
 }
 
 pub fn cstr2wcstring(input: &[u8]) -> WString {
-    let strlen = input.iter().position(|c| *c == b'\0').unwrap();
-    str2wcstring(&input[0..strlen])
+    let input = CStr::from_bytes_until_nul(input).unwrap().to_bytes();
+    str2wcstring(input)
 }
 
 pub(crate) fn charptr2wcstring(input: *const libc::c_char) -> WString {
-    let input: &[u8] = unsafe {
-        let strlen = libc::strlen(input);
-        slice::from_raw_parts(input.cast(), strlen)
-    };
+    let input: &[u8] = unsafe { CStr::from_ptr(input).to_bytes() };
     str2wcstring(input)
 }
 
diff --git a/src/wutil/mod.rs b/src/wutil/mod.rs
index 88b72a6ba..67e345c1c 100644
--- a/src/wutil/mod.rs
+++ b/src/wutil/mod.rs
@@ -21,7 +21,7 @@
 use crate::wcstringutil::{join_strings, wcs2string_callback};
 use errno::errno;
 pub use gettext::{wgettext, wgettext_fmt, wgettext_maybe_fmt, wgettext_str};
-use std::ffi::OsStr;
+use std::ffi::{CStr, OsStr};
 use std::fs::{self, canonicalize};
 use std::io::{self, Write};
 use std::os::unix::prelude::*;
@@ -89,9 +89,8 @@ pub fn perror(s: &str) {
         let _ = write!(stderr, "{s}: ");
     }
     let slice = unsafe {
-        let msg = libc::strerror(e) as *const u8;
-        let len = libc::strlen(msg as *const _);
-        std::slice::from_raw_parts(msg, len)
+        let msg = libc::strerror(e);
+        CStr::from_ptr(msg).to_bytes()
     };
     let _ = stderr.write_all(slice);
     let _ = stderr.write_all(b"\n");