From 8e822c39f82ec548d81641f7ffe191b90f395f0f Mon Sep 17 00:00:00 2001
From: Felicitas Pojtinger <felicitas@pojtinger.com>
Date: Fri, 19 Nov 2021 14:42:13 +0100
Subject: [PATCH] feat: Add `eject` cmd

---
 cmd/stbak/cmd/eject.go  | 36 ++++++++++++++++++++++++++++++++++++
 cmd/stbak/cmd/tell.go   |  2 +-
 pkg/controllers/tape.go | 18 ++++++++++++++++++
 3 files changed, 55 insertions(+), 1 deletion(-)
 create mode 100644 cmd/stbak/cmd/eject.go

diff --git a/cmd/stbak/cmd/eject.go b/cmd/stbak/cmd/eject.go
new file mode 100644
index 0000000..3c13159
--- /dev/null
+++ b/cmd/stbak/cmd/eject.go
@@ -0,0 +1,36 @@
+package cmd
+
+import (
+	"os"
+
+	"github.com/pojntfx/stfs/pkg/controllers"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+)
+
+var ejectCmd = &cobra.Command{
+	Use:     "eject",
+	Aliases: []string{"e"},
+	Short:   "Eject the tape (tape only)",
+	RunE: func(cmd *cobra.Command, args []string) error {
+		if err := viper.BindPFlags(cmd.PersistentFlags()); err != nil {
+			return err
+		}
+
+		f, err := os.OpenFile(viper.GetString(tapeFlag), os.O_RDONLY, os.ModeCharDevice)
+		if err != nil {
+			panic(err)
+		}
+		defer f.Close()
+
+		return controllers.EjectTape(f)
+	},
+}
+
+func init() {
+	ejectCmd.PersistentFlags().StringP(tapeFlag, "t", "/dev/nst0", "Tape drive to get the current record from")
+
+	viper.AutomaticEnv()
+
+	rootCmd.AddCommand(ejectCmd)
+}
diff --git a/cmd/stbak/cmd/tell.go b/cmd/stbak/cmd/tell.go
index 24d7e00..b05544a 100644
--- a/cmd/stbak/cmd/tell.go
+++ b/cmd/stbak/cmd/tell.go
@@ -11,7 +11,7 @@ import (
 
 var tellCmd = &cobra.Command{
 	Use:     "tell",
-	Aliases: []string{"tell"},
+	Aliases: []string{"t"},
 	Short:   "Get the current record (tape only)",
 	RunE: func(cmd *cobra.Command, args []string) error {
 		if err := viper.BindPFlags(cmd.PersistentFlags()); err != nil {
diff --git a/pkg/controllers/tape.go b/pkg/controllers/tape.go
index af58c50..b029234 100644
--- a/pkg/controllers/tape.go
+++ b/pkg/controllers/tape.go
@@ -12,6 +12,7 @@ const (
 	mtioCtop = 0x40086d01 // Do magnetic tape operation
 
 	mtFsf  = 1  // Forward space over FileMark, position at first record of next file
+	mtOffl = 7  // Rewind and put the drive offline (eject?)
 	mtEom  = 12 // Goto end of recorded media (for appending files)
 	mtSeek = 22 // Seek to block
 
@@ -96,3 +97,20 @@ func SeekToRecordOnTape(f *os.File, record int32) error {
 
 	return nil
 }
+
+func EjectTape(f *os.File) error {
+	if _, _, err := syscall.Syscall(
+		syscall.SYS_IOCTL,
+		f.Fd(),
+		mtioCtop,
+		uintptr(unsafe.Pointer(
+			&operation{
+				op: mtOffl,
+			},
+		)),
+	); err != 0 {
+		return err
+	}
+
+	return nil
+}