From e709db8003e7b13b09b46879612cc2b6bd8dc723 Mon Sep 17 00:00:00 2001
From: Olivier 'reivilibre <olivier@librepush.net>
Date: Tue, 8 Feb 2022 06:56:00 +0000
Subject: [PATCH] Add support for rmdir

---
 olivefs/src/filesystem.rs          | 39 ++++++++++++++++++++++++++----
 olivefs/src/requester.rs           | 10 ++++++++
 olivefs_common/src/messages.rs     |  4 +++
 olivefsd/src/server/connections.rs | 14 +++++++++--
 olivefsd/src/server/file_access.rs | 16 ++++++++++++
 5 files changed, 76 insertions(+), 7 deletions(-)

diff --git a/olivefs/src/filesystem.rs b/olivefs/src/filesystem.rs
index 80d5491..1bae26a 100644
--- a/olivefs/src/filesystem.rs
+++ b/olivefs/src/filesystem.rs
@@ -307,7 +307,7 @@ impl Filesystem for OliveFilesystem {
             reply.error(ENOENT);
             return;
         }
-            .to_owned();
+        .to_owned();
 
         let requester = self.requester.clone();
 
@@ -337,11 +337,40 @@ impl Filesystem for OliveFilesystem {
 
     /// Remove a directory.
     fn rmdir(&mut self, _req: &Request<'_>, parent: u64, name: &OsStr, reply: ReplyEmpty) {
-        debug!(
-            "[Not Implemented] rmdir(parent: {:#x?}, name: {:?})",
-            parent, name,
+        let name = if let Some(name) = name.to_str() {
+            name
+        } else {
+            // If we can't decode the filename, pretend it doesn't exist.
+            error!("rmdir: Filename not convertible.");
+            reply.error(ENOENT);
+            return;
+        }
+        .to_owned();
+
+        let requester = self.requester.clone();
+
+        self.spawn_with_error_handler(
+            async move {
+                let parent_vnode = VnodeId(
+                    parent
+                        .try_into()
+                        .context("Converting u64 inode to u32 VnodeId.")?,
+                );
+
+                match requester.rmdir(parent_vnode, name).await? {
+                    DataResponse::Success(()) => {
+                        reply.ok();
+                    }
+                    DataResponse::Error { code, message } => {
+                        warn!("rmdir(parent: {:#x?}) failed: {:?}", parent_vnode, message);
+                        reply.error(code as c_int);
+                    }
+                }
+
+                Ok(())
+            },
+            "rmdir",
         );
-        reply.error(ENOSYS);
     }
 
     /// Create a symbolic link.
diff --git a/olivefs/src/requester.rs b/olivefs/src/requester.rs
index 00c747b..7b5667f 100644
--- a/olivefs/src/requester.rs
+++ b/olivefs/src/requester.rs
@@ -232,6 +232,16 @@ impl Requester {
             .await
     }
 
+    pub async fn rmdir(
+        &self,
+        dir_vnode: VnodeId,
+        name: String,
+    ) -> anyhow::Result<DataResponse<()>> {
+        self.internal
+            .command(&DataCommand::RemoveDirectory { dir_vnode, name })
+            .await
+    }
+
     pub async fn open(&self, vnode: VnodeId, mode: OpenMode) -> anyhow::Result<DataResponse<u32>> {
         self.internal
             .command(&DataCommand::OpenFile { vnode, mode })
diff --git a/olivefs_common/src/messages.rs b/olivefs_common/src/messages.rs
index 8419324..aaaf1d6 100644
--- a/olivefs_common/src/messages.rs
+++ b/olivefs_common/src/messages.rs
@@ -99,6 +99,10 @@ pub enum DataCommand {
         dir_vnode: VnodeId,
         name: String,
     },
+    RemoveDirectory {
+        dir_vnode: VnodeId,
+        name: String,
+    },
 }
 
 #[derive(Serialize, Deserialize, Debug, Clone)]
diff --git a/olivefsd/src/server/connections.rs b/olivefsd/src/server/connections.rs
index cbe1f38..cb14a4a 100644
--- a/olivefsd/src/server/connections.rs
+++ b/olivefsd/src/server/connections.rs
@@ -144,7 +144,7 @@ pub async fn handle_command_stream(
                         .await
                         .unwrap_or_else(error_to_response),
                 )
-                    .await?;
+                .await?;
             }
             DataCommand::Unlink { dir_vnode, name } => {
                 send_bare_message(
@@ -154,7 +154,17 @@ pub async fn handle_command_stream(
                         .await
                         .unwrap_or_else(error_to_response),
                 )
-                    .await?;
+                .await?;
+            }
+            DataCommand::RemoveDirectory { dir_vnode, name } => {
+                send_bare_message(
+                    &mut tx,
+                    &file_access
+                        .rmdir(dir_vnode, name)
+                        .await
+                        .unwrap_or_else(error_to_response),
+                )
+                .await?;
             }
         }
     }
diff --git a/olivefsd/src/server/file_access.rs b/olivefsd/src/server/file_access.rs
index 9d1a325..cbeea7d 100644
--- a/olivefsd/src/server/file_access.rs
+++ b/olivefsd/src/server/file_access.rs
@@ -778,4 +778,20 @@ impl FileAccess {
         tokio::fs::remove_file(&target_path).await?;
         Ok(DataResponse::Success(()))
     }
+
+    /// Symlink safety:
+    ///   Makes an attempt to safely resolve symlinks, but there is a possibility of a TOCTOU race.
+    ///   TODO Revisit later for safety.
+    pub async fn rmdir(
+        &self,
+        dir_vnode: VnodeId,
+        name: String,
+    ) -> anyhow::Result<DataResponse<()>> {
+        let parent_dir_resolved = self
+            .resolve_vnode_including_follow_symlinks_safely_best_effort(dir_vnode)
+            .await?;
+        let target_path = parent_dir_resolved.join(name);
+        tokio::fs::remove_dir(&target_path).await?;
+        Ok(DataResponse::Success(()))
+    }
 }