chroot: implement --skip-chdir

src/uu/chroot/src/chroot.rs

@@ -6,13 +6,14 @@
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
 
-// spell-checker:ignore (ToDO) NEWROOT Userspec pstatus
+// spell-checker:ignore (ToDO) NEWROOT Userspec pstatus chdir
 mod error;
 
 use crate::error::ChrootError;
 use clap::{crate_version, Arg, Command};
 use std::ffi::CString;
 use std::io::Error;
+use std::os::unix::prelude::OsStrExt;
 use std::path::Path;
 use std::process;
 use uucore::error::{set_exit_code, UClapError, UResult};
@@ -29,6 +30,7 @@ mod options {
     pub const GROUPS: &str = "groups";
     pub const USERSPEC: &str = "userspec";
     pub const COMMAND: &str = "command";
+    pub const SKIP_CHDIR: &str = "skip-chdir";
 }
 
 #[uucore::main]
@@ -144,6 +146,15 @@ pub fn uu_app<'a>() -> Command<'a> {
                 )
                 .value_name("USER:GROUP"),
         )
+        .arg(
+            Arg::new(options::SKIP_CHDIR)
+                .long(options::SKIP_CHDIR)
+                .help(
+                    "Use this option to not change the working directory \
+                    to / after changing the root directory to newroot, \
+                    i.e., inside the chroot.",
+                ),
+        )
         .arg(
             Arg::new(options::COMMAND)
                 .value_hint(clap::ValueHint::CommandName)
@@ -158,6 +169,7 @@ fn set_context(root: &Path, options: &clap::ArgMatches) -> UResult<()> {
     let user_str = options.value_of(options::USER).unwrap_or_default();
     let group_str = options.value_of(options::GROUP).unwrap_or_default();
     let groups_str = options.value_of(options::GROUPS).unwrap_or_default();
+    let skip_chdir = options.contains_id(options::SKIP_CHDIR);
     let userspec = match userspec_str {
         Some(u) => {
             let s: Vec<&str> = u.split(':').collect();
@@ -175,20 +187,28 @@ fn set_context(root: &Path, options: &clap::ArgMatches) -> UResult<()> {
         (userspec[0], userspec[1])
     };
 
-    enter_chroot(root)?;
+    enter_chroot(root, skip_chdir)?;
 
     set_groups_from_str(groups_str)?;
     set_main_group(group)?;
     set_user(user)?;
     Ok(())
 }
 
-fn enter_chroot(root: &Path) -> UResult<()> {
-    std::env::set_current_dir(root).unwrap();
+fn enter_chroot(root: &Path, skip_chdir: bool) -> UResult<()> {
     let err = unsafe {
-        chroot(CString::new(".").unwrap().as_bytes_with_nul().as_ptr() as *const libc::c_char)
+        chroot(
+            CString::new(root.as_os_str().as_bytes().to_vec())
+                .unwrap()
+                .as_bytes_with_nul()
+                .as_ptr() as *const libc::c_char,
+        )
     };
+
     if err == 0 {
+        if !skip_chdir {
+            std::env::set_current_dir(root).unwrap();
+        }
         Ok(())
     } else {
         Err(ChrootError::CannotEnter(format!("{}", root.display()), Error::last_os_error()).into())

tests/by-util/test_chroot.rs

@@ -1,4 +1,4 @@
-// spell-checker:ignore (words) araba newroot userspec
+// spell-checker:ignore (words) araba newroot userspec chdir
 
 use crate::common::util::*;
 
@@ -143,3 +143,22 @@ fn test_chroot() {
         print!("Test skipped; requires root user");
     }
 }
+
+#[test]
+fn test_chroot_skip_chdir() {
+    let ts = TestScenario::new(util_name!());
+    let at = &ts.fixtures;
+
+    let dir = "CHROOT_DIR";
+    at.mkdir(dir);
+    let env_cd = std::env::current_dir().unwrap();
+    if let Ok(result) = run_ucmd_as_root(&ts, &[dir, "--skip-chdir", "pwd"]) {
+        // Should return the same path
+        assert_eq!(
+            result.success().no_stderr().stdout_str(),
+            env_cd.to_str().unwrap()
+        );
+    } else {
+        print!("Test skipped; requires root user");
+    }
+}

util/build-gnu.sh

@@ -184,6 +184,10 @@ sed -i "s/  {ERR_SUBST=>\"s\/(unrecognized|unknown) option \[-' \]\*foobar\[' \]
 
 # Remove the check whether a util was built. Otherwise tests against utils like "arch" are not run.
 sed -i "s|require_built_ |# require_built_ |g" init.cfg
+# Some tests are executed with the "nobody" user.
+# The check to verify if it works is based on the GNU coreutils version
+# making it too restrictive for us
+sed -i "s|\$PACKAGE_VERSION|[0-9]*|g" tests/rm/fail-2eperm.sh tests/mv/sticky-to-xpart.sh init.cfg
 
 # usage_vs_getopt.sh is heavily modified as it runs all the binaries
 # with the option -/ is used, clap is returning a better error than GNU's. Adjust the GNU test