cio: openFifos() use named return variables to use in defer()

This change is mostly defensive; when checking for the returned error, it's easy to make a mistake, and check for a "local" error, not the actual returned error. This patch changes the function to use a named return variable, which is checked in the defer. Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
containerd · Feb 1, 2021 · baf6c1d · baf6c1d
1 parent 6a2d399
commit baf6c1d
Showing 1 changed file with 10 additions and 12 deletions.
diff --git a/cio/io_unix.go b/cio/io_unix.go
@@ -103,38 +103,36 @@ func copyIO(fifos *FIFOSet, ioset *Streams) (*cio, error) {
 	}, nil
 }
 
-func openFifos(ctx context.Context, fifos *FIFOSet) (pipes, error) {
-	var err error
+func openFifos(ctx context.Context, fifos *FIFOSet) (f pipes, retErr error) {
 	defer func() {
-		if err != nil {
+		if retErr != nil {
 			fifos.Close()
 		}
 	}()
 
-	var f pipes
 	if fifos.Stdin != "" {
-		if f.Stdin, err = fifo.OpenFifo(ctx, fifos.Stdin, syscall.O_WRONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); err != nil {
-			return f, errors.Wrapf(err, "failed to open stdin fifo")
+		if f.Stdin, retErr = fifo.OpenFifo(ctx, fifos.Stdin, syscall.O_WRONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); retErr != nil {
+			return f, errors.Wrapf(retErr, "failed to open stdin fifo")
 		}
 		defer func() {
-			if err != nil && f.Stdin != nil {
+			if retErr != nil && f.Stdin != nil {
 				f.Stdin.Close()
 			}
 		}()
 	}
 	if fifos.Stdout != "" {
-		if f.Stdout, err = fifo.OpenFifo(ctx, fifos.Stdout, syscall.O_RDONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); err != nil {
-			return f, errors.Wrapf(err, "failed to open stdout fifo")
+		if f.Stdout, retErr = fifo.OpenFifo(ctx, fifos.Stdout, syscall.O_RDONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); retErr != nil {
+			return f, errors.Wrapf(retErr, "failed to open stdout fifo")
 		}
 		defer func() {
-			if err != nil && f.Stdout != nil {
+			if retErr != nil && f.Stdout != nil {
 				f.Stdout.Close()
 			}
 		}()
 	}
 	if !fifos.Terminal && fifos.Stderr != "" {
-		if f.Stderr, err = fifo.OpenFifo(ctx, fifos.Stderr, syscall.O_RDONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); err != nil {
-			return f, errors.Wrapf(err, "failed to open stderr fifo")
+		if f.Stderr, retErr = fifo.OpenFifo(ctx, fifos.Stderr, syscall.O_RDONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); retErr != nil {
+			return f, errors.Wrapf(retErr, "failed to open stderr fifo")
 		}
 	}
 	return f, nil