nice: Remove unsafe and reduce bin size

.vscode/cspell.dictionaries/workspace.wordlist.txt

@@ -8,6 +8,7 @@ advapi32-sys
 aho-corasick
 backtrace
 blake2b_simd
+rustix
 
 # * uutils project
 uutils

Cargo.toml

@@ -435,6 +435,7 @@ rstest = "0.26.0"
 rstest_reuse = "0.7.0"
 rustc-hash = "2.1.1"
 rust-ini = "0.21.0"
+rustix = "1.1.4"
 same-file = "1.0.6"
 self_cell = "1.0.4"
 selinux = "=0.6.0"

src/uu/nice/Cargo.toml

@@ -20,12 +20,11 @@ path = "src/nice.rs"
 
 [dependencies]
 clap = { workspace = true }
-libc = { workspace = true }
 uucore = { workspace = true }
 fluent = { workspace = true }
 
 [target.'cfg(unix)'.dependencies]
-nix = { workspace = true }
+rustix = { workspace = true, features = ["process"] }
 
 [[bin]]
 name = "nice"

src/uu/nice/src/nice.rs

@@ -6,9 +6,8 @@
 // spell-checker:ignore (ToDO) getpriority setpriority nstr PRIO
 
 use clap::{Arg, ArgAction, Command};
-use libc::PRIO_PROCESS;
 use std::ffi::OsString;
-use std::io::{Error, ErrorKind, Write, stdout};
+use std::io::{ErrorKind, Write, stdout};
 use std::num::IntErrorKind;
 use std::os::unix::process::CommandExt;
 use std::process;
@@ -110,14 +109,12 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
     let matches =
         uucore::clap_localization::handle_clap_result_with_exit_code(uu_app(), args, 125)?;
 
-    nix::errno::Errno::clear();
-    let mut niceness = unsafe { libc::getpriority(PRIO_PROCESS, 0) };
-    if Error::last_os_error().raw_os_error().unwrap() != 0 {
-        return Err(USimpleError::new(
-            125,
-            format!("getpriority: {}", Error::last_os_error()),
-        ));
-    }
+    let mut niceness = match rustix::process::getpriority_process(None) {
+        Ok(p) => p,
+        Err(e) => {
+            return Err(USimpleError::new(125, format!("getpriority: {e}")));
+        }
+    };
 
     let adjustment = if let Some(nstr) = matches.get_one::<String>(options::ADJUSTMENT) {
         if !matches.contains_id(options::COMMAND) {
@@ -152,8 +149,8 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
     // isn't writable. The GNU test suite checks specifically that the
     // exit code when failing to write the advisory is 125, but Rust
     // will produce an exit code of 101 when it panics.
-    if unsafe { libc::setpriority(PRIO_PROCESS, 0, niceness) } == -1 {
-        let warning_msg = translate!("nice-warning-setpriority", "util_name" => uucore::util_name(), "error" => Error::last_os_error());
+    if let Err(e) = rustix::process::setpriority_process(None, niceness) {
+        let warning_msg = translate!("nice-warning-setpriority", "util_name" => "nice", "error" => e.to_string() );
 
         if write!(std::io::stderr(), "{warning_msg}").is_err() {
             set_exit_code(125);
@@ -179,13 +176,13 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
 }
 
 pub fn uu_app() -> Command {
-    Command::new(uucore::util_name())
+    Command::new("nice")
         .about(translate!("nice-about"))
         .override_usage(format_usage(&translate!("nice-usage")))
         .trailing_var_arg(true)
         .infer_long_args(true)
         .version(uucore::crate_version!())
-        .help_template(uucore::localized_help_template(uucore::util_name()))
+        .help_template(uucore::localized_help_template("nice"))
         .arg(
             Arg::new(options::ADJUSTMENT)
                 .short('n')