From aa5ae7616e3c141c817f0545e0177ca85ac251d9 Mon Sep 17 00:00:00 2001
From: Sebastien Boeuf <sebastien.boeuf@intel.com>
Date: Fri, 24 Jan 2020 08:50:30 +0100
Subject: [PATCH] src: Fix map_err losing the inner error

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
---
 src/bin/vhost_user_fs.rs |  4 ++--
 src/main.rs              | 33 +++++++++++++++++----------------
 2 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/src/bin/vhost_user_fs.rs b/src/bin/vhost_user_fs.rs
index a6f120989..55c13f085 100644
--- a/src/bin/vhost_user_fs.rs
+++ b/src/bin/vhost_user_fs.rs
@@ -44,7 +44,7 @@ type VhostUserBackendResult<T> = std::result::Result<T, std::io::Error>;
 #[derive(Debug)]
 enum Error {
     /// Failed to create kill eventfd.
-    CreateKillEventFd,
+    CreateKillEventFd(io::Error),
     /// Failed to handle event other than input event.
     HandleEventNotEpollIn,
     /// Failed to handle unknown event.
@@ -89,7 +89,7 @@ impl<F: FileSystem + Send + Sync + 'static> VhostUserFsBackend<F> {
     fn new(fs: F) -> Result<Self> {
         Ok(VhostUserFsBackend {
             mem: None,
-            kill_evt: EventFd::new(EFD_NONBLOCK).map_err(|_| Error::CreateKillEventFd)?,
+            kill_evt: EventFd::new(EFD_NONBLOCK).map_err(Error::CreateKillEventFd)?,
             server: Arc::new(Server::new(fs)),
         })
     }
diff --git a/src/main.rs b/src/main.rs
index 5e36e5097..2df8c2266 100755
--- a/src/main.rs
+++ b/src/main.rs
@@ -1918,18 +1918,17 @@ mod tests {
         let mut counter = 0;
         loop {
             match (|| -> Result<(), Error> {
-                let tcp =
-                    TcpStream::connect(format!("{}:22", ip)).map_err(|_| Error::Connection)?;
+                let tcp = TcpStream::connect(format!("{}:22", ip)).map_err(Error::Connection)?;
                 let mut sess = Session::new().unwrap();
                 sess.set_tcp_stream(tcp);
-                sess.handshake().map_err(|_| Error::Connection)?;
+                sess.handshake().map_err(Error::Handshake)?;
 
                 sess.userauth_password("cloud", "cloud123")
-                    .map_err(|_| Error::Authentication)?;
+                    .map_err(Error::Authentication)?;
                 assert!(sess.authenticated());
 
-                let mut channel = sess.channel_session().map_err(|_| Error::Command)?;
-                channel.exec(command).map_err(|_| Error::Command)?;
+                let mut channel = sess.channel_session().map_err(Error::ChannelSession)?;
+                channel.exec(command).map_err(Error::Command)?;
 
                 // Intentionally ignore these results here as their failure
                 // does not precipitate a repeat
@@ -1953,10 +1952,12 @@ mod tests {
 
     #[derive(Debug)]
     enum Error {
-        Connection,
-        Authentication,
-        Command,
-        Parsing,
+        Connection(std::io::Error),
+        Handshake(ssh2::Error),
+        Authentication(ssh2::Error),
+        ChannelSession(ssh2::Error),
+        Command(ssh2::Error),
+        Parsing(std::num::ParseIntError),
     }
 
     impl std::error::Error for Error {}
@@ -2080,7 +2081,7 @@ mod tests {
                 .ssh_command("grep -c processor /proc/cpuinfo")?
                 .trim()
                 .parse()
-                .map_err(|_| Error::Parsing)?)
+                .map_err(Error::Parsing)?)
         }
 
         fn get_initial_apicid(&self) -> Result<u32, Error> {
@@ -2088,7 +2089,7 @@ mod tests {
                 .ssh_command("grep \"initial apicid\" /proc/cpuinfo | grep -o \"[0-9]*\"")?
                 .trim()
                 .parse()
-                .map_err(|_| Error::Parsing)?)
+                .map_err(Error::Parsing)?)
         }
 
         fn get_total_memory(&self) -> Result<u32, Error> {
@@ -2096,7 +2097,7 @@ mod tests {
                 .ssh_command("grep MemTotal /proc/meminfo | grep -o \"[0-9]*\"")?
                 .trim()
                 .parse()
-                .map_err(|_| Error::Parsing)?)
+                .map_err(Error::Parsing)?)
         }
 
         fn get_entropy(&self) -> Result<u32, Error> {
@@ -2104,7 +2105,7 @@ mod tests {
                 .ssh_command("cat /proc/sys/kernel/random/entropy_avail")?
                 .trim()
                 .parse()
-                .map_err(|_| Error::Parsing)?)
+                .map_err(Error::Parsing)?)
         }
 
         fn get_pci_bridge_class(&self) -> Result<String, Error> {
@@ -2189,8 +2190,8 @@ mod tests {
                 return Ok(false);
             }
 
-            let start_addr = u64::from_str_radix(args[0], 16).map_err(|_| Error::Parsing)?;
-            let end_addr = u64::from_str_radix(args[1], 16).map_err(|_| Error::Parsing)?;
+            let start_addr = u64::from_str_radix(args[0], 16).map_err(Error::Parsing)?;
+            let end_addr = u64::from_str_radix(args[1], 16).map_err(Error::Parsing)?;
 
             Ok(cache == (end_addr - start_addr + 1))
         }