Move runner into separate crate

1 files changed, 71 insertions, 0 deletions

diff --git a/crates/runner/src/init.rs b/crates/runner/src/init.rs
new file mode 100644
index 0000000..783faf4
--- /dev/null
+++ b/crates/runner/src/init.rs
@@ -0,0 +1,71 @@
+use std::fs::File;
+
+use nix::mount::{self, MsFlags};
+
+use common::error::*;
+
+use super::{tar, util::fs};
+use crate::paths;
+
+fn prepare_rootfs(rootfs: &str) -> Result<()> {
+	tar::unpack(File::open(paths::ROOTFS_ARCHIVE)?, rootfs)
+		.context("Unpacking build container rootfs failed")?;
+
+	mount::mount::<_, _, str, str>(Some(rootfs), rootfs, None, MsFlags::MS_BIND, None)
+		.context("Failed to bind mount container rootfs")?;
+
+	for dir in IntoIterator::into_iter(["pts", "shm"]) {
+		fs::mkdir(paths::join(&[rootfs, "dev", dir]))?;
+	}
+
+	for (link, target) in IntoIterator::into_iter([
+		("fd", "/proc/self/fd"),
+		("stdin", "/proc/self/fd/0"),
+		("stdout", "/proc/self/fd/1"),
+		("stderr", "/proc/self/fd/2"),
+		("ptmx", "pts/ptmx"),
+	]) {
+		let path = paths::join(&[rootfs, "dev", link]);
+		std::os::unix::fs::symlink(target, &path)
+			.with_context(|| format!("Failed to create link {}", path))?;
+	}
+
+	for dev in IntoIterator::into_iter(["null", "zero", "full", "random", "urandom", "tty"]) {
+		let source = paths::join(&["/dev", dev]);
+		let target = paths::join(&[rootfs, "dev", dev]);
+		fs::create(&target)?;
+		mount::mount::<str, str, str, str>(Some(&source), &target, None, MsFlags::MS_BIND, None)
+			.with_context(|| format!("Failed to bind mount {}", source))?;
+	}
+
+	mount::mount::<str, _, str, str>(
+		None,
+		rootfs,
+		None,
+		MsFlags::MS_REMOUNT | MsFlags::MS_BIND | MsFlags::MS_RDONLY,
+		None,
+	)
+	.context("Failed to mount container rootfs read-only")?;
+
+	Ok(())
+}
+
+pub fn init_runner() -> Result<()> {
+	fs::mkdir(paths::LAYER_STATE_DIR)?;
+	fs::mkdir(paths::OUTPUT_STATE_DIR)?;
+
+	mount::mount::<_, _, _, str>(
+		Some("buildtmp"),
+		paths::TMP_DIR,
+		Some("tmpfs"),
+		MsFlags::empty(),
+		None,
+	)
+	.context("Mounting build tmpfs failed")?;
+	mount::mount::<str, _, str, str>(None, paths::TMP_DIR, None, MsFlags::MS_PRIVATE, None)
+		.context("Failed to set MS_PRIVATE for build tmpfs")?;
+
+	prepare_rootfs(paths::ROOTFS_DIR)?;
+
+	Ok(())
+}