cp: preserve ACL xattrs with -p while excluding others

implement granular xattr handling to preserve ACLs with -p but not general xattrs

src/uu/cp/src/cp.rs

@@ -16,7 +16,7 @@ use std::os::unix::net::UnixListener;
 use std::path::{Path, PathBuf, StripPrefixError};
 use std::{fmt, io};
 #[cfg(all(unix, not(target_os = "android")))]
-use uucore::fsxattr::copy_xattrs;
+use uucore::fsxattr::{copy_acl_xattrs, copy_xattrs};
 use uucore::translate;
 
 use clap::{Arg, ArgAction, ArgMatches, Command, builder::ValueParser, value_parser};
@@ -1715,6 +1715,12 @@ pub(crate) fn copy_attributes(
             exacl::getfacl(source, None)
                 .and_then(|acl| exacl::setfacl(&[dest], &acl, None))
                 .map_err(|err| CpError::Error(err.to_string()))?;
+
+            // When preserving mode with -p, also preserve ACL xattrs
+            // ACLs are stored as xattrs (system.posix_acl_*) and should be
+            // preserved even when general xattrs are not
+            #[cfg(all(unix, not(target_os = "android")))]
+            copy_acl_xattrs(source, dest)?;
         }
 
         Ok(())

src/uucore/src/lib/features/fsxattr.rs

@@ -29,6 +29,32 @@ pub fn copy_xattrs<P: AsRef<Path>>(source: P, dest: P) -> std::io::Result<()> {
     Ok(())
 }
 
+/// Copies only ACL-related xattrs (system.posix_acl_*) from source to dest.
+///
+/// This is used for preserving ACLs with `-p` flag, which should preserve
+/// ACLs but not other extended attributes.
+///
+/// # Arguments
+///
+/// * `source` - A reference to the source path.
+/// * `dest` - A reference to the destination path.
+///
+/// # Returns
+///
+/// A result indicating success or failure.
+pub fn copy_acl_xattrs<P: AsRef<Path>>(source: P, dest: P) -> std::io::Result<()> {
+    for attr_name in xattr::list(&source)? {
+        if let Some(name_str) = attr_name.to_str() {
+            if name_str.starts_with("system.posix_acl_") {
+                if let Some(value) = xattr::get(&source, &attr_name)? {
+                    xattr::set(&dest, &attr_name, &value)?;
+                }
+            }
+        }
+    }
+    Ok(())
+}
+
 /// Retrieves the extended attributes (xattrs) of a given file or directory.
 ///
 /// # Arguments