Fix printenv non-UTF8 (#9728)

* printenv: Handle invalid UTF-8 encoding in variables

* test(printenv): Add test for non-UTF8 content in variable

src/uu/printenv/src/printenv.rs

@@ -3,10 +3,14 @@
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
 
-use clap::{Arg, ArgAction, Command};
 use std::env;
-use uucore::translate;
-use uucore::{error::UResult, format_usage};
+use std::io::Write;
+
+use clap::{Arg, ArgAction, Command};
+
+use uucore::error::UResult;
+use uucore::line_ending::LineEnding;
+use uucore::{format_usage, os_str_as_bytes, translate};
 
 static OPT_NULL: &str = "null";
 
@@ -21,15 +25,16 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
         .map(|v| v.map(ToString::to_string).collect())
         .unwrap_or_default();
 
-    let separator = if matches.get_flag(OPT_NULL) {
-        "\x00"
-    } else {
-        "\n"
-    };
+    let separator = LineEnding::from_zero_flag(matches.get_flag(OPT_NULL));
 
     if variables.is_empty() {
-        for (env_var, value) in env::vars() {
-            print!("{env_var}={value}{separator}");
+        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}");
         }
         return Ok(());
     }
@@ -41,8 +46,10 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
             error_found = true;
             continue;
         }
-        if let Ok(var) = env::var(env_var) {
-            print!("{var}{separator}");
+        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}");
         } else {
             error_found = true;
         }

tests/by-util/test_printenv.rs

@@ -90,3 +90,30 @@ fn test_null_separator() {
             .stdout_is("FOO\x00VALUE\x00");
     }
 }
+
+#[test]
+#[cfg(unix)]
+#[cfg(not(any(target_os = "freebsd", target_os = "android", target_os = "openbsd")))]
+fn test_non_utf8_value() {
+    use std::ffi::OsStr;
+    use std::os::unix::ffi::OsStrExt;
+    // Environment variable values can contain non-UTF-8 bytes on Unix.
+    // printenv should output them correctly, matching GNU behavior.
+    // Reproduces: LD_PRELOAD=$'/tmp/lib.so\xff' printenv LD_PRELOAD
+    let value_with_invalid_utf8 = OsStr::from_bytes(b"/tmp/lib.so\xff");
+
+    let result = new_ucmd!()
+        .env("LD_PRELOAD", value_with_invalid_utf8)
+        .arg("LD_PRELOAD")
+        .run();
+
+    // Use byte-based assertions to avoid UTF-8 conversion issues
+    // when the test framework tries to format error messages
+    assert!(
+        result.succeeded(),
+        "Command failed with exit code: {:?}, stderr: {:?}",
+        result.code(),
+        String::from_utf8_lossy(result.stderr())
+    );
+    result.stdout_is_bytes(b"/tmp/lib.so\xff\n");
+}