1 files changed, 65 insertions, 0 deletions
diff --git a/src/util/unix.rs b/src/util/unix.rs
new file mode 100644
index 0000000..ee0507c
--- /dev/null
+++ b/src/util/unix.rs
@@ -0,0 +1,65 @@
+use std::{fs::File, io::Result, os::unix::prelude::AsRawFd, path::Path};
+
+use nix::{dir::Dir, fcntl::OFlag, sys::stat::Mode, unistd};
+
+use super::ToIOResult;
+
+pub struct SetEUID(unistd::Uid);
+
+impl Drop for SetEUID {
+	fn drop(&mut self) {
+		unistd::seteuid(self.0).expect("failed to reset effective UID");
+	}
+}
+
+pub fn seteuid(uid: unistd::Uid) -> Result<SetEUID> {
+	let old_uid = unistd::geteuid();
+	unistd::seteuid(uid).to_io_result()?;
+	Ok(SetEUID(old_uid))
+}
+
+pub struct SetEGID(unistd::Gid);
+
+impl Drop for SetEGID {
+	fn drop(&mut self) {
+		unistd::setegid(self.0).expect("failed to reset effective GID");
+	}
+}
+
+pub fn setegid(gid: unistd::Gid) -> Result<SetEGID> {
+	let old_gid = unistd::getegid();
+	unistd::setegid(gid).to_io_result()?;
+	Ok(SetEGID(old_gid))
+}
+
+pub fn create_as<P: AsRef<Path>>(
+	path: P,
+	uid: Option<unistd::Uid>,
+	gid: Option<unistd::Gid>,
+) -> Result<File> {
+	let _setegid = gid.map(setegid).transpose()?;
+	let _seteuid = uid.map(seteuid).transpose()?;
+
+	File::create(path)
+}
+
+pub struct Chdir(Dir);
+
+impl Drop for Chdir {
+	fn drop(&mut self) {
+		unistd::fchdir(self.0.as_raw_fd()).expect("failed to revert directory change");
+	}
+}
+
+pub fn chdir<P: AsRef<Path>>(path: P) -> Result<Chdir> {
+	let dir = Dir::open(
+		".",
+		OFlag::O_PATH | OFlag::O_CLOEXEC | OFlag::O_NOFOLLOW,
+		Mode::empty(),
+	)
+	.to_io_result()?;
+
+	unistd::chdir(path.as_ref()).to_io_result()?;
+
+	Ok(Chdir(dir))
+}