From 5b1bcdb45312a7eb21beae6c097ecef721249c8d Mon Sep 17 00:00:00 2001
From: Valentin Haudiquet <valentin.haudiquet@canonical.com>
Date: Tue, 23 Dec 2025 17:19:41 +0100
Subject: [PATCH] exp: cross #7

---
 src/deb/cross.rs | 26 ++++++++++++++++++++++++++
 src/deb/local.rs |  5 +++++
 src/deb/mod.rs   |  6 ++++++
 3 files changed, 37 insertions(+)

diff --git a/src/deb/cross.rs b/src/deb/cross.rs
index 3a8434b..7a3ebf7 100644
--- a/src/deb/cross.rs
+++ b/src/deb/cross.rs
@@ -38,6 +38,20 @@ impl EphemeralContextGuard {
             return Err(format!("mmdebstrap failed for series {}", series).into());
         }
 
+        // Mount '/dev' inside the chroot
+        let status = context::current()
+            .command("sudo")
+            .arg("mount")
+            .arg("--bind")
+            .arg("/dev")
+            .arg(format!("{}/dev", chroot_path.display()))
+            .status()?;
+        if !status.success() {
+            // Clean up on failure
+            let _ = std::fs::remove_dir_all(&chroot_path);
+            return Err("Failed to mount /dev inside chroot".into());
+        }
+
         // Switch to an ephemeral context to build the package in the chroot
         context::manager().set_current_ephemeral(Context::new(ContextConfig::Unshare {
             path: chroot_path.to_string_lossy().to_string(),
@@ -59,6 +73,18 @@ impl Drop for EphemeralContextGuard {
             log::error!("Failed to restore context {}: {}", self.previous_context, e);
         }
 
+        // Unmount '/dev' inside the chroot
+        let status = context::current()
+            .command("sudo")
+            .arg("umount")
+            .arg(format!("{}/dev", &self.chroot_path.display()))
+            .status();
+        if status.is_err() || !status.unwrap().success() {
+            // If we fail to umount, then we can't remove (would remove /dev/xx on host)
+            log::error!("Failed to umount /dev inside chroot. Not cleaning up.");
+            return;
+        }
+
         // Remove chroot directory
         // We use the restored context to execute the cleanup command
         let result = context::current()
diff --git a/src/deb/local.rs b/src/deb/local.rs
index aa0ba70..17242fa 100644
--- a/src/deb/local.rs
+++ b/src/deb/local.rs
@@ -52,6 +52,11 @@ pub fn build(
         .arg("fakeroot");
     if cross {
         cmd.arg(format!("crossbuild-essential-{arch}"));
+        cmd.arg(format!("libc6-{arch}-cross"));
+        cmd.arg(format!("libc6-dev-{arch}-cross"));
+        cmd.arg("dpkg-cross");
+        cmd.arg(format!("libc6:{arch}"));
+        cmd.arg(format!("libc6-dev:{arch}"));
     }
     let status = cmd.status()?;
     if !status.success() {
diff --git a/src/deb/mod.rs b/src/deb/mod.rs
index c41e333..2737152 100644
--- a/src/deb/mod.rs
+++ b/src/deb/mod.rs
@@ -144,4 +144,10 @@ mod tests {
     async fn test_deb_hello_ubuntu_end_to_end() {
         test_build_end_to_end("hello", "noble", None, false).await;
     }
+
+    #[tokio::test]
+    #[cfg(target_arch = "x86_64")]
+    async fn test_deb_hello_ubuntu_cross_end_to_end() {
+        test_build_end_to_end("hello", "noble", Some("riscv64"), true).await;
+    }
 }