Fix udev rule for EBS mappings

packages/os/ebs-volumes.rules

@@ -7,9 +7,9 @@ ATTRS{model}!="Amazon Elastic Block Store", GOTO="ebs_volumes_end"
 ENV{DEVTYPE}=="disk", ATTR{queue/io_timeout}="4294967295"
 
 # Add symlink for disk
-KERNEL=="nvme[0-9]*n[0-9]*", ENV{DEVTYPE}=="disk", IMPORT{program}="/usr/bin/ghostdog ebs-device-name $devnode", SYMLINK+="$env{XVD_DEVICE_NAME}"
+KERNEL=="nvme[0-9]*n[0-9]*", ENV{DEVTYPE}=="disk", IMPORT{program}="/usr/bin/ghostdog ebs-device-name $devnode", SYMLINK+="disk/by-ebs-id/$env{XVD_DEVICE_NAME}"
 
 # Add symlink for partition
-KERNEL=="nvme[0-9]*n[0-9]*p[0-9]*", ENV{DEVTYPE}=="partition", IMPORT{parent}="XVD_DEVICE_NAME", SYMLINK+="$env{XVD_DEVICE_NAME}$number"
+KERNEL=="nvme[0-9]*n[0-9]*p[0-9]*", ENV{DEVTYPE}=="partition", IMPORT{parent}="XVD_DEVICE_NAME", SYMLINK+="disk/by-ebs-id/$env{XVD_DEVICE_NAME}$number"
 
 LABEL="ebs_volumes_end"

sources/ghostdog/src/main.rs

@@ -117,7 +117,12 @@ fn parse_device_name(device_info: &[u8], path: String) -> Result<String> {
     let offset = NVME_IDENTIFY_DATA_SIZE - 1024;
     let device_name = &device_info[offset..offset + 32];
 
-    Ok(String::from_utf8_lossy(device_name).trim_end().to_string())
+    // Remove `/dev` in case the returned device name includes it, the udev
+    // rule already includes that prefix
+    Ok(String::from_utf8_lossy(device_name)
+        .trim_start_matches("/dev/")
+        .trim_end()
+        .to_string())
 }
 
 /// Print the device type in the environment key format udev expects.
@@ -235,4 +240,25 @@ mod test {
         let data = gpt_data(partition_type, partition_name);
         assert_eq!(find_device_type(&mut Cursor::new(&data)).unwrap(), "system");
     }
+
+    #[test]
+    fn test_valid_device_info() {
+        for device_name in ["xvdcz", "/dev/xvdcz"] {
+            let device_info = build_device_info(device_name);
+            assert_eq!(
+                parse_device_name(&device_info, "".to_string()).unwrap(),
+                "xvdcz".to_string()
+            );
+        }
+    }
+
+    fn build_device_info(device_name: &str) -> Vec<u8> {
+        let mut device_name = device_name.as_bytes().to_vec();
+        let mut device_info: Vec<u8> = vec![0; NVME_IDENTIFY_DATA_SIZE - 1024];
+        let mut padding = vec![32; NVME_IDENTIFY_DATA_SIZE - device_info.len() - device_name.len()];
+        device_info.append(&mut device_name);
+        device_info.append(&mut padding);
+
+        device_info
+    }
 }