improve error handling a bit

3 files changed, 15 insertions, 9 deletions

diff --git a/src/command.rs b/src/command.rs
index e11df57..d02df2d 100644
--- a/src/command.rs
+++ b/src/command.rs
@@ -30,7 +30,7 @@ impl Command for std::process::Command {
             });
         }
 
-        let child = self.spawn()?;
+        let child = self.spawn().map_err(Error::Spawn)?;
 
         Ok(Child { child, pty })
     }
diff --git a/src/error.rs b/src/error.rs
index 5b836de..b414cf9 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -1,10 +1,13 @@
 #[derive(thiserror::Error, Debug)]
 pub enum Error {
     #[error("error creating pty")]
-    CreatePtyMaster(#[from] nix::Error),
+    CreatePty(#[source] nix::Error),
 
-    #[error("error creating pty")]
-    CreatePtySlave(#[from] std::io::Error),
+    #[error("error opening pts at {0}")]
+    OpenPts(std::path::PathBuf, #[source] std::io::Error),
+
+    #[error("error spawning subprocess")]
+    Spawn(#[source] std::io::Error),
 }
 
 pub type Result<T> = std::result::Result<T, Error>;
diff --git a/src/pty.rs b/src/pty.rs
index f0ebcd3..d76aa6b 100644
--- a/src/pty.rs
+++ b/src/pty.rs
@@ -11,11 +11,13 @@ impl Pty {
     pub fn new() -> Result<Self> {
         let pt = nix::pty::posix_openpt(
             nix::fcntl::OFlag::O_RDWR | nix::fcntl::OFlag::O_NOCTTY,
-        )?;
-        nix::pty::grantpt(&pt)?;
-        nix::pty::unlockpt(&pt)?;
+        )
+        .map_err(Error::CreatePty)?;
+        nix::pty::grantpt(&pt).map_err(Error::CreatePty)?;
+        nix::pty::unlockpt(&pt).map_err(Error::CreatePty)?;
 
-        let ptsname = nix::pty::ptsname_r(&pt)?.into();
+        let ptsname =
+            nix::pty::ptsname_r(&pt).map_err(Error::CreatePty)?.into();
 
         let pt_fd = pt.into_raw_fd();
         let pt = unsafe { std::fs::File::from_raw_fd(pt_fd) };
@@ -31,6 +33,7 @@ impl Pty {
         Ok(std::fs::OpenOptions::new()
             .read(true)
             .write(true)
-            .open(&self.ptsname)?)
+            .open(&self.ptsname)
+            .map_err(|e| Error::OpenPts(self.ptsname.clone(), e))?)
     }
 }