w: Fix formatting of command line value

Author: alxndrv

src/uu/w/src/w.rs

@@ -140,9 +140,13 @@ fn format_time(time: String) -> Result<String, chrono::format::ParseError> {
 }
 
 #[cfg(target_os = "linux")]
-fn fetch_cmdline(pid: i32) -> Result<String, std::io::Error> {
+fn fetch_cmdline(pid: i32) -> String {
     let cmdline_path = Path::new("/proc").join(pid.to_string()).join("cmdline");
     fs::read_to_string(cmdline_path)
+        .unwrap_or_default()
+        .split_terminator("\0")
+        .collect::<Vec<_>>()
+        .join(" ")
 }
 
 #[cfg(target_os = "linux")]
@@ -168,7 +172,7 @@ fn fetch_user_info() -> Result<Vec<UserInfo>, std::io::Error> {
                 idle_time: fetch_idle_time(entry.tty_device())?,
                 jcpu: format!("{jcpu:.2}"),
                 pcpu: fetch_pcpu_time(entry.pid()).unwrap_or_default().to_string(),
-                command: fetch_cmdline(entry.pid()).unwrap_or_default(),
+                command: fetch_cmdline(entry.pid()),
             };
             user_info_list.push(user_info);
         }
@@ -452,11 +456,8 @@ mod tests {
     fn test_fetch_cmdline() {
         // uucore's utmpx returns an i32, so we cast to that to mimic it.
         let pid = process::id() as i32;
-        let path = Path::new("/proc").join(pid.to_string()).join("cmdline");
-        assert_eq!(
-            fs::read_to_string(path).unwrap(),
-            fetch_cmdline(pid).unwrap()
-        );
+        let cmdline = std::env::args().collect::<Vec<String>>().join(" ");
+        assert_eq!(cmdline, fetch_cmdline(pid));
     }
 
     #[test]