Extract directory entries after all others when using Archive::unpack. (

#249)

If they are extracted in order, they may fail if a directory's
permissions prevent descendant files from being written. So extracting
them after all other entries ensures that any files that need to be
created can be without being subject to the final permissions.

Closes #242.

Co-authored-by: Alex Franchuk <afranchuk@caci.com>

src/archive.rs

@@ -172,10 +172,22 @@ impl<'a> Archive<dyn Read + 'a> {
         // NotFound exception.
         let dst = &dst.canonicalize().unwrap_or(dst.to_path_buf());
 
+        // Delay any directory entries until the end (they will be created if needed by
+        // descendants), to ensure that directory permissions do not interfer with descendant
+        // extraction.
+        let mut directories = Vec::new();
         for entry in self._entries()? {
             let mut file = entry.map_err(|e| TarError::new("failed to iterate over archive", e))?;
-            file.unpack_in(dst)?;
+            if file.header().entry_type() == crate::EntryType::Directory {
+                directories.push(file);
+            } else {
+                file.unpack_in(dst)?;
+            }
+        }
+        for mut dir in directories {
+            dir.unpack_in(dst)?;
         }
+
         Ok(())
     }
 

tests/all.rs

@@ -1149,3 +1149,29 @@ fn append_long_multibyte() {
         name.pop();
     }
 }
+
+#[test]
+fn read_only_directory_containing_files() {
+    let td = t!(TempBuilder::new().prefix("tar-rs").tempdir());
+
+    let mut b = Builder::new(Vec::<u8>::new());
+
+    let mut h = Header::new_gnu();
+    t!(h.set_path("dir/"));
+    h.set_size(0);
+    h.set_entry_type(EntryType::dir());
+    h.set_mode(0o444);
+    h.set_cksum();
+    t!(b.append(&h, "".as_bytes()));
+
+    let mut h = Header::new_gnu();
+    t!(h.set_path("dir/file"));
+    h.set_size(2);
+    h.set_entry_type(EntryType::file());
+    h.set_cksum();
+    t!(b.append(&h, "hi".as_bytes()));
+
+    let contents = t!(b.into_inner());
+    let mut ar = Archive::new(&contents[..]);
+    assert!(ar.unpack(td.path()).is_ok());
+}