env/printenv: dedup the code

src/uu/env/src/env.rs

@@ -24,13 +24,13 @@ use nix::sys::signal::{SigHandler::SigIgn, Signal, signal};
 use std::borrow::Cow;
 use std::env;
 use std::ffi::{OsStr, OsString};
-use std::io::{self, Write};
+use std::io;
 #[cfg(unix)]
 use std::os::unix::ffi::OsStrExt;
 #[cfg(unix)]
 use std::os::unix::process::CommandExt;
 
-use uucore::display::{OsWrite, Quotable};
+use uucore::display::{Quotable, print_all_env_vars};
 use uucore::error::{ExitCode, UError, UResult, USimpleError, UUsageError};
 use uucore::line_ending::LineEnding;
 #[cfg(unix)]
@@ -99,19 +99,6 @@ struct Options<'a> {
     ignore_signal: Vec<usize>,
 }
 
-/// print `name=value` env pairs on screen
-fn print_env(line_ending: LineEnding) -> io::Result<()> {
-    let stdout_raw = io::stdout();
-    let mut stdout = stdout_raw.lock();
-    for (n, v) in env::vars_os() {
-        stdout.write_all_os(&n)?;
-        stdout.write_all(b"=")?;
-        stdout.write_all_os(&v)?;
-        write!(stdout, "{line_ending}")?;
-    }
-    Ok(())
-}
-
 fn parse_name_value_opt<'a>(opts: &mut Options<'a>, opt: &'a OsStr) -> UResult<bool> {
     // is it a NAME=VALUE like opt ?
     let wrap = NativeStr::<'a>::new(opt);
@@ -552,7 +539,7 @@ impl EnvAppData {
 
         if opts.program.is_empty() {
             // no program provided, so just dump all env vars to stdout
-            print_env(opts.line_ending)?;
+            print_all_env_vars(opts.line_ending)?;
         } else {
             return self.run_program(&opts, self.do_debug_printing);
         }

src/uu/printenv/src/printenv.rs

@@ -8,9 +8,10 @@ use std::io::Write;
 
 use clap::{Arg, ArgAction, Command};
 
+use uucore::display::{OsWrite, print_all_env_vars};
 use uucore::error::UResult;
 use uucore::line_ending::LineEnding;
-use uucore::{format_usage, os_str_as_bytes, translate};
+use uucore::{format_usage, translate};
 
 static OPT_NULL: &str = "null";
 
@@ -28,14 +29,7 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
     let separator = LineEnding::from_zero_flag(matches.get_flag(OPT_NULL));
 
     if variables.is_empty() {
-        for (env_var, value) in env::vars_os() {
-            let env_bytes = os_str_as_bytes(&env_var)?;
-            let val_bytes = os_str_as_bytes(&value)?;
-            std::io::stdout().lock().write_all(env_bytes)?;
-            print!("=");
-            std::io::stdout().lock().write_all(val_bytes)?;
-            print!("{separator}");
-        }
+        print_all_env_vars(separator)?;
         return Ok(());
     }
 
@@ -47,9 +41,9 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
             continue;
         }
         if let Some(var) = env::var_os(env_var) {
-            let val_bytes = os_str_as_bytes(&var)?;
-            std::io::stdout().lock().write_all(val_bytes)?;
-            print!("{separator}");
+            let mut stdout = std::io::stdout().lock();
+            stdout.write_all_os(&var)?;
+            write!(stdout, "{separator}")?;
         } else {
             error_found = true;
         }

src/uucore/src/lib/mods/display.rs

@@ -24,7 +24,9 @@
 //! # Ok::<(), std::io::Error>(())
 //! ```
 
+use std::env;
 use std::ffi::OsStr;
+use std::fmt;
 use std::fs::File;
 use std::io::{self, BufWriter, Stdout, StdoutLock, Write as IoWrite};
 
@@ -117,3 +119,18 @@ impl OsWrite for Box<dyn OsWrite> {
         this.write_all_os(buf)
     }
 }
+
+/// Print all environment variables in the format `name=value` with the specified line ending.
+///
+/// This function handles non-UTF-8 environment variable names and values correctly by using
+/// raw bytes on Unix systems.
+pub fn print_all_env_vars<T: fmt::Display>(line_ending: T) -> io::Result<()> {
+    let mut stdout = io::stdout().lock();
+    for (name, value) in env::vars_os() {
+        stdout.write_all_os(&name)?;
+        stdout.write_all(b"=")?;
+        stdout.write_all_os(&value)?;
+        write!(stdout, "{line_ending}")?;
+    }
+    Ok(())
+}