install: add FreeBSD's -U (unprivileged) option

docs/src/extensions.md

@@ -204,3 +204,7 @@ With `-U`/`--no-utf8`, you can interpret input files as 8-bit ASCII rather than
 ## `expand`
 
 `expand` also offers the `-U`/`--no-utf8` option to interpret input files as 8-bit ASCII instead of UTF-8.
+
+## `install`
+
+`install` offers FreeBSD's `-U` unprivileged option to not change the owner, the group, or the file flags of the destination.

src/uu/install/locales/en-US.ftl

@@ -19,6 +19,7 @@ install-help-verbose = explain what is being done
 install-help-preserve-context = preserve security context
 install-help-context = set security context of files and directories
 install-help-default-context = set SELinux security context of destination file and each created directory to default type
+install-help-unprivileged = do not require elevated privileges to change the owner, the group, or the file flags of the destination
 
 # Error messages
 install-error-dir-needs-arg = { $util_name } with -d requires at least one argument.

src/uu/install/locales/fr-FR.ftl

@@ -19,6 +19,7 @@ install-help-verbose = expliquer ce qui est fait
 install-help-preserve-context = préserver le contexte de sécurité
 install-help-context = définir le contexte de sécurité des fichiers et répertoires
 install-help-default-context = définir le contexte de sécurité SELinux du fichier de destination et de chaque répertoire créé au type par défaut
+install-help-unprivileged = ne pas nécessiter de privilèges élevés pour changer le propriétaire, le groupe ou les attributs du fichier de destination
 
 # Messages d'erreur
 install-error-dir-needs-arg = { $util_name } avec -d nécessite au moins un argument.

src/uu/install/src/install.rs

@@ -62,6 +62,7 @@ pub struct Behavior {
     preserve_context: bool,
     context: Option<String>,
     default_context: bool,
+    unprivileged: bool,
 }
 
 #[derive(Error, Debug)]
@@ -163,6 +164,7 @@ static OPT_VERBOSE: &str = "verbose";
 static OPT_PRESERVE_CONTEXT: &str = "preserve-context";
 static OPT_CONTEXT: &str = "context";
 static OPT_DEFAULT_CONTEXT: &str = "default-context";
+static OPT_UNPRIVILEGED: &str = "unprivileged";
 
 static ARG_FILES: &str = "files";
 
@@ -317,6 +319,13 @@ pub fn uu_app() -> Command {
                 .value_hint(clap::ValueHint::AnyPath)
                 .value_parser(clap::value_parser!(OsString)),
         )
+        .arg(
+            Arg::new(OPT_UNPRIVILEGED)
+                .short('U')
+                .long(OPT_UNPRIVILEGED)
+                .help(translate!("install-help-unprivileged"))
+                .action(ArgAction::SetTrue),
+        )
 }
 
 /// Determine behavior, given command line arguments.
@@ -416,6 +425,7 @@ fn behavior(matches: &ArgMatches) -> UResult<Behavior> {
 
     let context = matches.get_one::<String>(OPT_CONTEXT).cloned();
     let default_context = matches.get_flag(OPT_DEFAULT_CONTEXT);
+    let unprivileged = matches.get_flag(OPT_UNPRIVILEGED);
 
     Ok(Behavior {
         main_function,
@@ -439,6 +449,7 @@ fn behavior(matches: &ArgMatches) -> UResult<Behavior> {
         preserve_context: matches.get_flag(OPT_PRESERVE_CONTEXT),
         context,
         default_context,
+        unprivileged,
     })
 }
 
@@ -479,7 +490,7 @@ fn directory(paths: &[OsString], b: &Behavior) -> UResult<()> {
 
                 // Set SELinux context for all created directories if needed
                 #[cfg(feature = "selinux")]
-                if b.context.is_some() || b.default_context {
+                if should_set_selinux_context(b) {
                     let context = get_context_for_selinux(b);
                     set_selinux_context_for_directories_install(path_to_create.as_path(), context);
                 }
@@ -498,15 +509,17 @@ fn directory(paths: &[OsString], b: &Behavior) -> UResult<()> {
                 continue;
             }
 
-            show_if_err!(chown_optional_user_group(path, b));
+            if !b.unprivileged {
+                show_if_err!(chown_optional_user_group(path, b));
 
-            // Set SELinux context for directory if needed
-            #[cfg(feature = "selinux")]
-            if b.default_context {
-                show_if_err!(set_selinux_default_context(path));
-            } else if b.context.is_some() {
-                let context = get_context_for_selinux(b);
-                show_if_err!(set_selinux_security_context(path, context));
+                // Set SELinux context for directory if needed
+                #[cfg(feature = "selinux")]
+                if b.default_context {
+                    show_if_err!(set_selinux_default_context(path));
+                } else if b.context.is_some() {
+                    let context = get_context_for_selinux(b);
+                    show_if_err!(set_selinux_security_context(path, context));
+                }
             }
         }
         // If the exit code was set, or show! has been called at least once
@@ -628,7 +641,7 @@ fn standard(mut paths: Vec<OsString>, b: &Behavior) -> UResult<()> {
 
                 // Set SELinux context for all created directories if needed
                 #[cfg(feature = "selinux")]
-                if b.context.is_some() || b.default_context {
+                if should_set_selinux_context(b) {
                     let context = get_context_for_selinux(b);
                     set_selinux_context_for_directories_install(to_create, context);
                 }
@@ -918,7 +931,9 @@ fn set_ownership_and_permissions(to: &Path, b: &Behavior) -> UResult<()> {
         return Err(InstallError::ChmodFailed(to.to_path_buf()).into());
     }
 
-    chown_optional_user_group(to, b)?;
+    if !b.unprivileged {
+        chown_optional_user_group(to, b)?;
+    }
 
     Ok(())
 }
@@ -984,16 +999,18 @@ fn copy(from: &Path, to: &Path, b: &Behavior) -> UResult<()> {
     }
 
     #[cfg(feature = "selinux")]
-    if b.preserve_context {
-        uucore::selinux::preserve_security_context(from, to)
-            .map_err(|e| InstallError::SelinuxContextFailed(e.to_string()))?;
-    } else if b.default_context {
-        set_selinux_default_context(to)
-            .map_err(|e| InstallError::SelinuxContextFailed(e.to_string()))?;
-    } else if b.context.is_some() {
-        let context = get_context_for_selinux(b);
-        set_selinux_security_context(to, context)
-            .map_err(|e| InstallError::SelinuxContextFailed(e.to_string()))?;
+    if !b.unprivileged {
+        if b.preserve_context {
+            uucore::selinux::preserve_security_context(from, to)
+                .map_err(|e| InstallError::SelinuxContextFailed(e.to_string()))?;
+        } else if b.default_context {
+            set_selinux_default_context(to)
+                .map_err(|e| InstallError::SelinuxContextFailed(e.to_string()))?;
+        } else if b.context.is_some() {
+            let context = get_context_for_selinux(b);
+            set_selinux_security_context(to, context)
+                .map_err(|e| InstallError::SelinuxContextFailed(e.to_string()))?;
+        }
     }
 
     if b.verbose {
@@ -1022,6 +1039,11 @@ fn get_context_for_selinux(b: &Behavior) -> Option<&String> {
     }
 }
 
+#[cfg(feature = "selinux")]
+fn should_set_selinux_context(b: &Behavior) -> bool {
+    !b.unprivileged && (b.context.is_some() || b.default_context)
+}
+
 /// Check if a file needs to be copied due to ownership differences when no explicit group is specified.
 /// Returns true if the destination file's ownership would differ from what it should be after installation.
 fn needs_copy_for_ownership(to: &Path, to_meta: &fs::Metadata) -> bool {
@@ -1113,25 +1135,25 @@ fn need_copy(from: &Path, to: &Path, b: &Behavior) -> bool {
     }
 
     #[cfg(feature = "selinux")]
-    if b.preserve_context && contexts_differ(from, to) {
+    if !b.unprivileged && b.preserve_context && contexts_differ(from, to) {
         return true;
     }
 
     // TODO: if -P (#1809) and from/to contexts mismatch, return true.
 
     // Check if the owner ID is specified and differs from the destination file's owner.
     if let Some(owner_id) = b.owner_id {
-        if owner_id != to_meta.uid() {
+        if !b.unprivileged && owner_id != to_meta.uid() {
             return true;
         }
     }
 
     // Check if the group ID is specified and differs from the destination file's group.
     if let Some(group_id) = b.group_id {
-        if group_id != to_meta.gid() {
+        if !b.unprivileged && group_id != to_meta.gid() {
             return true;
         }
-    } else if needs_copy_for_ownership(to, &to_meta) {
+    } else if !b.unprivileged && needs_copy_for_ownership(to, &to_meta) {
         return true;
     }
 

tests/by-util/test_install.rs

@@ -2489,3 +2489,35 @@ fn test_install_non_utf8_paths() {
 
     ucmd.arg("-D").arg(source_file).arg(&target_path).succeeds();
 }
+
+#[test]
+fn test_install_unprivileged_option_u_skips_chown() {
+    // This test only makes sense when not running as root.
+    if geteuid() == 0 {
+        return;
+    }
+
+    let scene = TestScenario::new(util_name!());
+    let at = &scene.fixtures;
+
+    let src = "source_file";
+    let dst_fail = "target_fail";
+    let dst_ok = "target_ok";
+    at.touch(src);
+
+    // Without -U, attempting to chown to root should fail for an unprivileged user.
+    let res = scene.ucmd().args(&["--owner=root", src, dst_fail]).run();
+
+    res.failure();
+
+    // With -U, install should not require elevated privileges for owner/group changes,
+    // meaning it should succeed and leave ownership as the current user.
+    scene
+        .ucmd()
+        .args(&["-U", "--owner=root", src, dst_ok])
+        .succeeds()
+        .no_stderr();
+
+    assert!(at.file_exists(dst_ok));
+    assert_eq!(at.metadata(dst_ok).uid(), geteuid());
+}