tests: add support for initramfs

the integration test creates an initramfs image based on AlpineLinux mini root filesystem
with a simple /init script that just echoes a string to the console. The string
is passed via the kernel cmdline as an environment variable.

Signed-off-by: Damjan Georgievski <gdamjan@gmail.com>

scripts/run_integration_tests.sh

@@ -68,6 +68,32 @@ if [ ! -f "$EOAN_OS_RAW_IMAGE" ]; then
     popd
 fi
 
+ALPINE_MINIROOTFS_URL="http://dl-cdn.alpinelinux.org/alpine/v3.11/releases/x86_64/alpine-minirootfs-3.11.3-x86_64.tar.gz"
+ALPINE_MINIROOTFS_TARBALL="$WORKLOADS_DIR/alpine-minirootfs-x86_64.tar.gz"
+if [ ! -f "$ALPINE_MINIROOTFS_TARBALL" ]; then
+    pushd $WORKLOADS_DIR
+    time wget --quiet $ALPINE_MINIROOTFS_URL -O $ALPINE_MINIROOTFS_TARBALL || exit 1
+    popd
+fi
+
+ALPINE_INITRAMFS_IMAGE="$WORKLOADS_DIR/alpine_initramfs.img"
+if [ ! -f "$ALPINE_INITRAMFS_IMAGE" ]; then
+    pushd $WORKLOADS_DIR
+    mkdir alpine-minirootfs
+    tar xf "$ALPINE_MINIROOTFS_TARBALL" -C alpine-minirootfs
+    cat > alpine-minirootfs/init <<-EOF
+		#! /bin/sh
+		mount -t devtmpfs dev /dev
+		echo \$TEST_STRING > /dev/console
+		poweroff -f
+	EOF
+    chmod +x alpine-minirootfs/init
+    cd alpine-minirootfs
+    find . -print0 |
+        cpio --null --create --verbose --owner root:root --format=newc > "$ALPINE_INITRAMFS_IMAGE"
+    popd
+fi
+
 pushd $WORKLOADS_DIR
 sha1sum sha1sums --check
 if [ $? -ne 0 ]; then

scripts/sha1sums

@@ -4,3 +4,4 @@ cf7cfa783082fc4d6b4d1c0a53e4402648c14b82 clear-31311-cloudguest.img
 8db9cc58b01452ce2d06c313177e6e74d8582d93 bionic-server-cloudimg-amd64-raw.img
 4a452cdcf781f95d31a1668ecb92a937c176709a eoan-server-cloudimg-amd64.img
 91fdfb21df8920fd55915edf7669282cda2505f6 eoan-server-cloudimg-amd64-raw.img
+d4a44acc6014d5f83dea1c625c43d677a95fa75f alpine-minirootfs-x86_64.tar.gz

tests/integration.rs

@@ -3842,4 +3842,45 @@ mod tests {
             Ok(())
         });
     }
+
+    #[test]
+    fn test_initramfs() {
+        test_block!(tb, "", {
+            let mut clear = ClearDiskConfig::new();
+            let guest = Guest::new(&mut clear);
+            let mut workload_path = dirs::home_dir().unwrap();
+            workload_path.push("workloads");
+
+            let mut kernel_path = workload_path.clone();
+            kernel_path.push("vmlinux");
+
+            let mut initramfs_path = workload_path;
+            initramfs_path.push("alpine_initramfs.img");
+
+            let test_string = String::from("axz34i9rylotd8n50wbv6kcj7f2qushme1pg");
+            let cmdline = format!("console=hvc0 quiet TEST_STRING={}", test_string);
+
+            let mut child = GuestCommand::new(&guest)
+                .args(&["--kernel", kernel_path.to_str().unwrap()])
+                .args(&["--initramfs", initramfs_path.to_str().unwrap()])
+                .args(&["--cmdline", &cmdline])
+                .capture_output()
+                .spawn()
+                .unwrap();
+
+            thread::sleep(std::time::Duration::new(20, 0));
+
+            let _ = child.kill();
+            match child.wait_with_output() {
+                Ok(out) => {
+                    let s = String::from_utf8_lossy(&out.stdout);
+                    println!("{}", s);
+                    aver_ne!(tb, s.lines().position(|line| line == test_string), None);
+                }
+                Err(_) => aver!(tb, false),
+            }
+
+            Ok(())
+        });
+    }
 }