efi/file: fixup dir/file name

Fat filename can be 12, that is filename with length of 8 and extension
name with length of 3 and a separator like '.'. But directory name
length limits to 11. That's say some name can't be shown correctly. For
that case, we can do a fixup to give a correct name to userspace.

Fixes: cloud-hypervisor#261
Signed-off-by: Jianyong Wu <[email protected]>

src/fat.rs

@@ -232,6 +232,17 @@ fn name_to_str(input: &str, output: &mut [u8]) {
             break;
         }
     }
+
+    // Fixup for Director or file name, when the length of its name and extend name equals 11. There maybe no
+    // separation between them. If so, add it.
+    if output[10] >= b'a' && output[10] <= b'z'
+        || output[10] >= b'A' && output[10] <= b'Z' && output[7] != b' ' && output[7] != b'.'
+    {
+        output[11] = output[10];
+        output[10] = output[9];
+        output[9] = output[8];
+        output[8] = b'.';
+    }
 }
 
 impl<'a> Read for Node<'a> {
@@ -282,7 +293,9 @@ impl<'a> Directory<'a> {
 
         match self.filesystem.read(u64::from(sector), data) {
             Ok(_) => {}
-            Err(e) => return Err(Error::Block(e)),
+            Err(e) => {
+                return Err(Error::Block(e));
+            }
         };
 
         Ok(())
@@ -348,6 +361,7 @@ impl<'a> Directory<'a> {
 
             for i in self.offset..dirs.len() {
                 let d = &dirs[i];
+                let s = d.size;
                 // Last entry
                 if d.name[0] == 0x0 {
                     return Err(Error::EndOfFile);
@@ -403,9 +417,9 @@ impl<'a> Directory<'a> {
         }
     }
 
-    pub fn next_node(&mut self) -> Result<(Node, [u8; 11]), Error> {
+    pub fn next_node(&mut self) -> Result<(Node, [u8; 12]), Error> {
         let de = self.next_entry()?;
-        let mut name = [0_u8; 11];
+        let mut name = [0_u8; 12];
         name_to_str(core::str::from_utf8(&de.name).unwrap(), &mut name);
 
         match de.file_type {
@@ -1172,16 +1186,16 @@ mod tests {
 
     #[test]
     fn test_name_to_str() {
-        let mut s = [0_u8; 11];
+        let mut s = [0_u8; 12];
         super::name_to_str("X       ABC", &mut s);
         assert_eq!(crate::common::ascii_strip(&s), "X.ABC");
-        let mut s = [0_u8; 11];
+        let mut s = [0_u8; 12];
         super::name_to_str(".", &mut s);
         assert_eq!(crate::common::ascii_strip(&s), ".");
-        let mut s = [0_u8; 11];
+        let mut s = [0_u8; 12];
         super::name_to_str("..", &mut s);
         assert_eq!(crate::common::ascii_strip(&s), "..");
-        let mut s = [0_u8; 11];
+        let mut s = [0_u8; 12];
         super::name_to_str("ABCDEFGHIJK", &mut s);
         assert_eq!(crate::common::ascii_strip(&s), "ABCDEFGHIJK");
     }