tape: implement LTO userspace driver

src/tape/drive/lto/mod.rs

@@ -0,0 +1,420 @@
+//! Driver for LTO SCSI tapes
+//!
+//! This is a userspace drive implementation using SG_IO.
+//!
+//! Why we do not use the Linux tape driver:
+//!
+//! - missing features (MAM, Encryption, ...)
+//!
+//! - strange permission handling - only root (or CAP_SYS_RAWIO) can
+//!   do SG_IO (SYS_RAW_IO)
+//!
+//! - unability to detect EOT (you just get EIO)
+
+mod sg_tape;
+pub use sg_tape::*;
+
+use std::fs::{OpenOptions, File};
+use std::os::unix::fs::OpenOptionsExt;
+use std::os::unix::io::{AsRawFd, FromRawFd, RawFd};
+use std::convert::TryFrom;
+
+use anyhow::{bail, format_err, Error};
+use nix::fcntl::{fcntl, FcntlArg, OFlag};
+
+use proxmox::{
+    tools::Uuid,
+    sys::error::SysResult,
+};
+
+use crate::{
+    config,
+    tools::run_command,
+    backup::{
+        Fingerprint,
+        KeyConfig,
+    },
+    api2::types::{
+        MamAttribute,
+        LtoDriveAndMediaStatus,
+        LtoTapeDrive,
+    },
+    tape::{
+        TapeRead,
+        TapeWrite,
+        drive::{
+            TapeDriver,
+            TapeAlertFlags,
+            Lp17VolumeStatistics,
+            mam_extract_media_usage,
+        },
+        file_formats::{
+            PROXMOX_BACKUP_MEDIA_SET_LABEL_MAGIC_1_0,
+            MediaSetLabel,
+            MediaContentHeader,
+        },
+    },
+};
+
+impl LtoTapeDrive {
+
+    /// Open a tape device
+    ///
+    /// This does additional checks:
+    ///
+    /// - check if it is a non-rewinding tape device
+    /// - check if drive is ready (tape loaded)
+    /// - check block size
+    /// - for autoloader only, try to reload ejected tapes
+    pub fn open(&self) -> Result<LtoTapeHandle, Error> {
+
+        proxmox::try_block!({
+            let file = open_lto_tape_device(&self.path)?;
+
+            let mut handle = LtoTapeHandle::new(file)?;
+
+            if !handle.sg_tape.test_unit_ready().is_ok() {
+                // for autoloader only, try to reload ejected tapes
+                if self.changer.is_some() {
+                    let _ = handle.sg_tape.load(); // just try, ignore error
+                }
+            }
+
+            handle.sg_tape.wait_until_ready()?;
+
+            // Only root can set driver options, so we cannot
+            // handle.set_default_options()?;
+
+            Ok(handle)
+        }).map_err(|err: Error| format_err!("open drive '{}' ({}) failed - {}", self.name, self.path, err))
+    }
+}
+
+/// Lto Tape device handle
+pub struct LtoTapeHandle {
+    sg_tape: SgTape,
+}
+
+impl LtoTapeHandle {
+
+    /// Creates a new instance
+    pub fn new(file: File) -> Result<Self, Error> {
+        let sg_tape = SgTape::new(file)?;
+        Ok(Self { sg_tape })
+    }
+
+    /// Set all options we need/want
+    pub fn set_default_options(&self) -> Result<(), Error> {
+        // fixme
+        Ok(())
+    }
+
+    /// Write a single EOF mark without flushing buffers
+    pub fn write_filemarks(&mut self, count: usize) -> Result<(), std::io::Error> {
+        self.sg_tape.write_filemarks(count, false)
+    }
+
+    /// Get Tape and Media status
+    pub fn get_drive_and_media_status(&mut self) -> Result<LtoDriveAndMediaStatus, Error>  {
+
+        let (file_number, block_number) = match self.sg_tape.position() {
+            Ok(position) => (
+                Some(position.logical_file_id),
+                Some(position.logical_object_number),
+            ),
+            Err(_) => (None, None),
+        };
+
+        let options = String::from("FIXME");
+
+        let alert_flags = self.tape_alert_flags()
+            .map(|flags| format!("{:?}", flags))
+            .ok();
+
+        let mut status = LtoDriveAndMediaStatus {
+            blocksize: 0, // fixme: remove
+            density: None, // fixme
+            status: String::from("FIXME"),
+            options,
+            alert_flags,
+            file_number,
+            block_number,
+            manufactured: None,
+            bytes_read: None,
+            bytes_written: None,
+            medium_passes: None,
+            medium_wearout: None,
+            volume_mounts: None,
+        };
+
+        if self.sg_tape.test_unit_ready()? {
+
+            if let Ok(mam) = self.cartridge_memory() {
+
+                let usage = mam_extract_media_usage(&mam)?;
+
+                status.manufactured = Some(usage.manufactured);
+                status.bytes_read = Some(usage.bytes_read);
+                status.bytes_written = Some(usage.bytes_written);
+
+                if let Ok(volume_stats) = self.volume_statistics() {
+
+                    let passes = std::cmp::max(
+                        volume_stats.beginning_of_medium_passes,
+                        volume_stats.middle_of_tape_passes,
+                    );
+
+                    // assume max. 16000 medium passes
+                    // see: https://en.wikipedia.org/wiki/Linear_Tape-Open
+                    let wearout: f64 = (passes as f64)/(16000.0 as f64);
+
+                    status.medium_passes = Some(passes);
+                    status.medium_wearout = Some(wearout);
+
+                    status.volume_mounts = Some(volume_stats.volume_mounts);
+                }
+            }
+        }
+
+        Ok(status)
+    }
+
+    pub fn load(&mut self) ->  Result<(), Error> {
+        self.sg_tape.load()
+    }
+
+    /// Read Cartridge Memory (MAM Attributes)
+    pub fn cartridge_memory(&mut self) -> Result<Vec<MamAttribute>, Error> {
+        self.sg_tape.cartridge_memory()
+     }
+
+    /// Read Volume Statistics
+    pub fn volume_statistics(&mut self) -> Result<Lp17VolumeStatistics, Error> {
+        self.sg_tape.volume_statistics()
+    }
+}
+
+
+impl TapeDriver for LtoTapeHandle {
+
+    fn sync(&mut self) -> Result<(), Error> {
+        self.sg_tape.sync()?;
+        Ok(())
+    }
+
+    /// Go to the end of the recorded media (for appending files).
+    fn move_to_eom(&mut self) -> Result<(), Error> {
+        self.sg_tape.move_to_eom()
+    }
+
+    fn forward_space_count_files(&mut self, count: usize) -> Result<(), Error> {
+        self.sg_tape.space_filemarks(isize::try_from(count)?)
+    }
+
+    fn backward_space_count_files(&mut self, count: usize) -> Result<(), Error> {
+        self.sg_tape.space_filemarks(-isize::try_from(count)?)
+    }
+
+    fn rewind(&mut self) -> Result<(), Error> {
+        self.sg_tape.rewind()
+    }
+
+    fn current_file_number(&mut self) -> Result<u64, Error> {
+        self.sg_tape.current_file_number()
+    }
+
+    fn erase_media(&mut self, fast: bool) -> Result<(), Error> {
+        self.rewind()?; // important - erase from BOT
+        self.sg_tape.erase_media(fast)
+    }
+
+    fn read_next_file<'a>(&'a mut self) -> Result<Option<Box<dyn TapeRead + 'a>>, std::io::Error> {
+        let reader = self.sg_tape.open_reader()?;
+        let handle = match reader {
+            Some(reader) => {
+                let reader: Box<dyn TapeRead> = Box::new(reader);
+                Some(reader)
+            }
+            None => None,
+        };
+
+        Ok(handle)
+    }
+
+    fn write_file<'a>(&'a mut self) -> Result<Box<dyn TapeWrite + 'a>, std::io::Error> {
+        let handle = self.sg_tape.open_writer();
+        Ok(Box::new(handle))
+    }
+
+    fn write_media_set_label(
+        &mut self,
+        media_set_label: &MediaSetLabel,
+        key_config: Option<&KeyConfig>,
+    ) -> Result<(), Error> {
+
+        let file_number = self.current_file_number()?;
+        if file_number != 1 {
+            self.rewind()?;
+            self.forward_space_count_files(1)?; // skip label
+        }
+
+        let file_number = self.current_file_number()?;
+        if file_number != 1 {
+            bail!("write_media_set_label failed - got wrong file number ({} != 1)", file_number);
+        }
+
+        self.set_encryption(None)?;
+
+        { // limit handle scope
+            let mut handle = self.write_file()?;
+
+            let mut value = serde_json::to_value(media_set_label)?;
+            if media_set_label.encryption_key_fingerprint.is_some() {
+                match key_config {
+                    Some(key_config) => {
+                        value["key-config"] = serde_json::to_value(key_config)?;
+                    }
+                    None => {
+                        bail!("missing encryption key config");
+                    }
+                }
+            }
+
+            let raw = serde_json::to_string_pretty(&value)?;
+
+            let header = MediaContentHeader::new(PROXMOX_BACKUP_MEDIA_SET_LABEL_MAGIC_1_0, raw.len() as u32);
+            handle.write_header(&header, raw.as_bytes())?;
+            handle.finish(false)?;
+        }
+
+        self.sync()?; // sync data to tape
+
+        Ok(())
+    }
+
+    /// Rewind and put the drive off line (Eject media).
+    fn eject_media(&mut self) -> Result<(), Error> {
+        self.sg_tape.eject()
+    }
+
+    /// Read Tape Alert Flags
+    fn tape_alert_flags(&mut self) -> Result<TapeAlertFlags, Error> {
+        self.sg_tape.tape_alert_flags()
+    }
+
+    /// Set or clear encryption key
+    ///
+    /// Note: Only 'root' can read secret encryption keys, so we need
+    /// to spawn setuid binary 'sg-tape-cmd'.
+    fn set_encryption(
+        &mut self,
+        key_fingerprint: Option<(Fingerprint, Uuid)>,
+    ) -> Result<(), Error> {
+
+        if nix::unistd::Uid::effective().is_root() {
+
+            if let Some((ref key_fingerprint, ref uuid)) = key_fingerprint {
+
+                let (key_map, _digest) = config::tape_encryption_keys::load_keys()?;
+                match key_map.get(key_fingerprint) {
+                    Some(item) => {
+
+                        // derive specialized key for each media-set
+
+                        let mut tape_key = [0u8; 32];
+
+                        let uuid_bytes: [u8; 16] = uuid.as_bytes().clone();
+
+                        openssl::pkcs5::pbkdf2_hmac(
+                            &item.key,
+                            &uuid_bytes,
+                            10,
+                            openssl::hash::MessageDigest::sha256(),
+                            &mut tape_key)?;
+
+                        return self.sg_tape.set_encryption(Some(tape_key));
+                    }
+                    None => bail!("unknown tape encryption key '{}'", key_fingerprint),
+                }
+            } else {
+                return self.sg_tape.set_encryption(None);
+            }
+        }
+
+        let output = if let Some((fingerprint, uuid)) = key_fingerprint {
+            let fingerprint = crate::tools::format::as_fingerprint(fingerprint.bytes());
+            run_sg_tape_cmd("encryption", &[
+                "--fingerprint", &fingerprint,
+                "--uuid", &uuid.to_string(),
+            ], self.sg_tape.file_mut().as_raw_fd())?
+        } else {
+            run_sg_tape_cmd("encryption", &[], self.sg_tape.file_mut().as_raw_fd())?
+        };
+        let result: Result<(), String> = serde_json::from_str(&output)?;
+        result.map_err(|err| format_err!("{}", err))
+    }
+}
+
+/// Check for correct Major/Minor numbers
+pub fn check_tape_is_lto_tape_device(file: &File) -> Result<(), Error> {
+
+    let stat = nix::sys::stat::fstat(file.as_raw_fd())?;
+
+    let devnum = stat.st_rdev;
+
+    let major = unsafe { libc::major(devnum) };
+    let _minor = unsafe { libc::minor(devnum) };
+
+    if major == 9 {
+        bail!("not a scsi-generic tape device (cannot use linux tape devices)");
+    }
+
+    if major != 21 {
+        bail!("not a scsi-generic tape device");
+    }
+
+    Ok(())
+}
+
+/// Opens a Lto tape device
+///
+/// The open call use O_NONBLOCK, but that flag is cleard after open
+/// succeeded. This also checks if the device is a non-rewinding tape
+/// device.
+pub fn open_lto_tape_device(
+    path: &str,
+) -> Result<File, Error> {
+
+    let file = OpenOptions::new()
+        .read(true)
+        .write(true)
+        .custom_flags(libc::O_NONBLOCK)
+        .open(path)?;
+
+    // clear O_NONBLOCK from now on.
+
+    let flags = fcntl(file.as_raw_fd(), FcntlArg::F_GETFL)
+        .into_io_result()?;
+
+    let mut flags = OFlag::from_bits_truncate(flags);
+    flags.remove(OFlag::O_NONBLOCK);
+
+    fcntl(file.as_raw_fd(), FcntlArg::F_SETFL(flags))
+        .into_io_result()?;
+
+    check_tape_is_lto_tape_device(&file)
+        .map_err(|err| format_err!("device type check {:?} failed - {}", path, err))?;
+
+    Ok(file)
+}
+
+fn run_sg_tape_cmd(subcmd: &str, args: &[&str], fd: RawFd) -> Result<String, Error> {
+    let mut command = std::process::Command::new(
+        "/usr/lib/x86_64-linux-gnu/proxmox-backup/sg-tape-cmd");
+    command.args(&[subcmd]);
+    command.args(&["--stdin"]);
+    command.args(args);
+    let device_fd = nix::unistd::dup(fd)?;
+    command.stdin(unsafe { std::process::Stdio::from_raw_fd(device_fd)});
+    run_command(command, None)
+}

src/tape/drive/lto/sg_tape.rs

@@ -0,0 +1,445 @@
+use std::time::SystemTime;
+use std::fs::{File, OpenOptions};
+use std::os::unix::fs::OpenOptionsExt;
+use std::os::unix::io::AsRawFd;
+use std::path::Path;
+
+use anyhow::{bail, format_err, Error};
+use endian_trait::Endian;
+use nix::fcntl::{fcntl, FcntlArg, OFlag};
+
+use proxmox::{
+    sys::error::SysResult,
+    tools::io::ReadExt,
+};
+
+use crate::{
+    api2::types::{
+        MamAttribute,
+    },
+    tape::{
+        BlockRead,
+        BlockReadStatus,
+        BlockWrite,
+        file_formats::{
+            BlockedWriter,
+            BlockedReader,
+        },
+        drive::{
+            TapeAlertFlags,
+            Lp17VolumeStatistics,
+            read_mam_attributes,
+            read_tape_alert_flags,
+            read_volume_statistics,
+            set_encryption,
+        },
+    },
+    tools::sgutils2::{
+        SgRaw,
+        SenseInfo,
+        ScsiError,
+        InquiryInfo,
+        scsi_inquiry,
+    },
+};
+
+#[repr(C, packed)]
+#[derive(Endian, Debug, Copy, Clone)]
+pub struct ReadPositionLongPage {
+    flags: u8,
+    reserved: [u8;3],
+    partition_number: u32,
+    pub logical_object_number: u64,
+    pub logical_file_id: u64,
+    obsolete: [u8;8],
+}
+
+pub struct SgTape {
+    file: File,
+}
+
+impl SgTape {
+
+    const SCSI_TAPE_DEFAULT_TIMEOUT: usize = 60*2; // 2 minutes
+
+    /// Create a new instance
+    ///
+    /// Uses scsi_inquiry to check the device type.
+    pub fn new(mut file: File) -> Result<Self, Error> {
+
+        let info = scsi_inquiry(&mut file)?;
+
+        if info.peripheral_type != 1 {
+            bail!("not a tape device (peripheral_type = {})", info.peripheral_type);
+        }
+        Ok(Self { file })
+    }
+
+    pub fn open<P: AsRef<Path>>(path: P) -> Result<SgTape, Error> {
+        // do not wait for media, use O_NONBLOCK
+        let file = OpenOptions::new()
+            .read(true)
+            .write(true)
+            .custom_flags(libc::O_NONBLOCK)
+            .open(path)?;
+
+        // then clear O_NONBLOCK
+        let flags = fcntl(file.as_raw_fd(), FcntlArg::F_GETFL)
+            .into_io_result()?;
+
+        let mut flags = OFlag::from_bits_truncate(flags);
+        flags.remove(OFlag::O_NONBLOCK);
+
+        fcntl(file.as_raw_fd(), FcntlArg::F_SETFL(flags))
+            .into_io_result()?;
+
+        Self::new(file)
+    }
+
+    pub fn inquiry(&mut self) -> Result<InquiryInfo, Error> {
+        scsi_inquiry(&mut self.file)
+    }
+
+    pub fn erase_media(&mut self, _fast: bool) -> Result<(), Error> {
+        // fixme:
+        unimplemented!();
+    }
+
+    pub fn rewind(&mut self) -> Result<(), Error> {
+
+        let mut sg_raw = SgRaw::new(&mut self.file, 16)?;
+        sg_raw.set_timeout(Self::SCSI_TAPE_DEFAULT_TIMEOUT);
+        let mut cmd = Vec::new();
+        cmd.extend(&[0x01, 0, 0, 0, 0, 0]); // REWIND
+
+        sg_raw.do_command(&cmd)
+            .map_err(|err| format_err!("rewind failed - {}", err))?;
+
+        Ok(())
+    }
+
+    pub fn position(&mut self) -> Result<ReadPositionLongPage, Error> {
+
+        let expected_size = std::mem::size_of::<ReadPositionLongPage>();
+
+        let mut sg_raw = SgRaw::new(&mut self.file, 32)?;
+        sg_raw.set_timeout(30); // use short timeout
+        let mut cmd = Vec::new();
+        cmd.extend(&[0x34, 0x06, 0, 0, 0, 0, 0, 0, 0, 0]); // READ POSITION LONG FORM
+
+        let data = sg_raw.do_command(&cmd)
+            .map_err(|err| format_err!("read position failed - {}", err))?;
+
+        let page = proxmox::try_block!({
+            if data.len() != expected_size {
+                bail!("got unexpected data len ({} != {}", data.len(), expected_size);
+            }
+
+            let mut reader = &data[..];
+
+            let page: ReadPositionLongPage = unsafe { reader.read_be_value()? };
+
+            Ok(page)
+        }).map_err(|err: Error| format_err!("decode position page failed - {}", err))?;
+
+        if page.partition_number != 0 {
+            bail!("detecthed partitioned tape - not supported");
+        }
+
+        println!("DATA: {:?}", page);
+
+        Ok(page)
+    }
+
+    pub fn current_file_number(&mut self) -> Result<u64, Error> {
+        let position = self.position()?;
+        Ok(position.logical_file_id)
+    }
+
+    pub fn locate(&mut self) ->  Result<(), Error> {
+        // fixme: impl LOCATE
+        unimplemented!();
+    }
+
+    pub fn move_to_eom(&mut self) ->  Result<(), Error> {
+        let mut sg_raw = SgRaw::new(&mut self.file, 16)?;
+        sg_raw.set_timeout(Self::SCSI_TAPE_DEFAULT_TIMEOUT);
+        let mut cmd = Vec::new();
+        cmd.extend(&[0x11, 0x03, 0, 0, 0, 0]); // SPACE(6) move to EOD
+
+        sg_raw.do_command(&cmd)
+            .map_err(|err| format_err!("move to EOD failed - {}", err))?;
+
+        Ok(())
+    }
+
+    pub fn space_filemarks(&mut self, count: isize) ->  Result<(), Error> {
+        let mut sg_raw = SgRaw::new(&mut self.file, 16)?;
+        sg_raw.set_timeout(Self::SCSI_TAPE_DEFAULT_TIMEOUT);
+        let mut cmd = Vec::new();
+
+        // Use short command if possible (supported by all drives)
+        if (count <= 0x7fffff) && (count > -0x7fffff) {
+            cmd.extend(&[0x11, 0x01]); // SPACE(6) with filemarks
+            cmd.push(((count >> 16) & 0xff) as u8);
+            cmd.push(((count >> 8) & 0xff) as u8);
+            cmd.push((count & 0xff) as u8);
+            cmd.push(0); //control byte
+        } else {
+
+            cmd.extend(&[0x91, 0x01, 0, 0]); // SPACE(16) with filemarks
+            let count: i64 = count as i64;
+            cmd.extend(&count.to_be_bytes());
+            cmd.extend(&[0, 0, 0, 0]);
+        }
+
+        sg_raw.do_command(&cmd)
+            .map_err(|err| format_err!("space filemarks failed - {}", err))?;
+
+        Ok(())
+    }
+
+    pub fn eject(&mut self) ->  Result<(), Error> {
+        let mut sg_raw = SgRaw::new(&mut self.file, 16)?;
+        sg_raw.set_timeout(Self::SCSI_TAPE_DEFAULT_TIMEOUT);
+        let mut cmd = Vec::new();
+        cmd.extend(&[0x1B, 0, 0, 0, 0, 0]); // LODA/UNLOAD HOLD=0, LOAD=0
+
+        sg_raw.do_command(&cmd)
+            .map_err(|err| format_err!("eject failed - {}", err))?;
+
+        Ok(())
+    }
+
+    pub fn load(&mut self) ->  Result<(), Error> {
+        let mut sg_raw = SgRaw::new(&mut self.file, 16)?;
+        sg_raw.set_timeout(Self::SCSI_TAPE_DEFAULT_TIMEOUT);
+        let mut cmd = Vec::new();
+        cmd.extend(&[0x1B, 0, 0, 0, 0b0000_0001, 0]); // LODA/UNLOAD HOLD=0, LOAD=1
+
+        sg_raw.do_command(&cmd)
+            .map_err(|err| format_err!("load media failed - {}", err))?;
+
+        Ok(())
+    }
+
+    pub fn write_filemarks(
+        &mut self,
+        count: usize,
+        immediate: bool,
+    ) ->  Result<(), std::io::Error> {
+
+        if count > 255 {
+            proxmox::io_bail!("write_filemarks failed: got strange count '{}'", count);
+        }
+
+        let mut sg_raw = SgRaw::new(&mut self.file, 16)
+            .map_err(|err| proxmox::io_format_err!("write_filemarks failed (alloc) - {}", err))?;
+
+        sg_raw.set_timeout(Self::SCSI_TAPE_DEFAULT_TIMEOUT);
+        let mut cmd = Vec::new();
+        cmd.push(0x10);
+        if immediate {
+            cmd.push(1); // IMMED=1
+        } else {
+            cmd.push(0); // IMMED=0
+        }
+        cmd.extend(&[0, 0, count as u8]); // COUNT
+        cmd.push(0); // control byte
+
+        sg_raw.do_command(&cmd)
+            .map_err(|err| proxmox::io_format_err!("write filemark failed - {}", err))?;
+
+        Ok(())
+    }
+
+    // Flush tape buffers (WEOF with count 0 => flush)
+    pub fn sync(&mut self) -> Result<(), std::io::Error> {
+        self.write_filemarks(0, false)?;
+        Ok(())
+    }
+
+    pub fn test_unit_ready(&mut self) -> Result<bool, Error> {
+
+        let mut sg_raw = SgRaw::new(&mut self.file, 16)?;
+        sg_raw.set_timeout(30); // use short timeout
+        let mut cmd = Vec::new();
+        cmd.extend(&[0x00, 0, 0, 0, 0, 0]); // TEST UNIT READY
+
+        // fixme: check sense
+        sg_raw.do_command(&cmd)
+            .map_err(|err| format_err!("unit not ready - {}", err))?;
+
+        Ok(true)
+
+    }
+
+    pub fn wait_until_ready(&mut self) -> Result<(), Error> {
+
+        let start = SystemTime::now();
+        let max_wait = std::time::Duration::new(Self::SCSI_TAPE_DEFAULT_TIMEOUT as u64, 0);
+
+        loop {
+            match self.test_unit_ready() {
+                Ok(true) => return Ok(()),
+                _ => {
+                    std::thread::sleep(std::time::Duration::new(1, 0));
+                    if start.elapsed()? > max_wait {
+                        bail!("wait_until_ready failed - got timeout");
+                    }
+                }
+            }
+        }
+    }
+
+    /// Read Tape Alert Flags
+    pub fn tape_alert_flags(&mut self) -> Result<TapeAlertFlags, Error> {
+        read_tape_alert_flags(&mut self.file)
+    }
+
+    /// Read Cartridge Memory (MAM Attributes)
+    pub fn cartridge_memory(&mut self) -> Result<Vec<MamAttribute>, Error> {
+        read_mam_attributes(&mut self.file)
+    }
+
+    /// Read Volume Statistics
+    pub fn volume_statistics(&mut self) -> Result<Lp17VolumeStatistics, Error> {
+        return read_volume_statistics(&mut self.file);
+    }
+
+    pub fn set_encryption(
+        &mut self,
+        key: Option<[u8; 32]>,
+    ) -> Result<(), Error> {
+        set_encryption(&mut self.file, key)
+    }
+
+    // Note: use alloc_page_aligned_buffer to alloc data transfer buffer
+    //
+    // Returns true if the drive reached the Logical End Of Media (early warning)
+    fn write_block(&mut self, data: &[u8]) -> Result<bool, std::io::Error> {
+
+        let transfer_len = data.len();
+
+        if transfer_len > 0xFFFFFF {
+           proxmox::io_bail!("write failed - data too large");
+        }
+
+        let mut sg_raw = SgRaw::new(&mut self.file, 0)
+            .unwrap(); // cannot fail with size 0
+
+        sg_raw.set_timeout(Self::SCSI_TAPE_DEFAULT_TIMEOUT);
+        let mut cmd = Vec::new();
+        cmd.push(0x0A);  // WRITE
+        cmd.push(0x00); // VARIABLE SIZED BLOCKS
+        cmd.push(((transfer_len >> 16) & 0xff) as u8);
+        cmd.push(((transfer_len >> 8) & 0xff) as u8);
+        cmd.push((transfer_len & 0xff) as u8);
+        cmd.push(0); // control byte
+
+        //println!("WRITE {:?}", cmd);
+        //println!("WRITE {:?}", data);
+
+        sg_raw.do_out_command(&cmd, data)
+            .map_err(|err| proxmox::io_format_err!("write failed - {}", err))?;
+
+        // fixme: LEOM?
+
+        Ok(false)
+    }
+
+    fn read_block(&mut self, buffer: &mut [u8]) -> Result<BlockReadStatus, std::io::Error> {
+        let transfer_len = buffer.len();
+
+        if transfer_len > 0xFFFFFF {
+            proxmox::io_bail!("read failed - buffer too large");
+        }
+
+        let mut sg_raw = SgRaw::new(&mut self.file, 0)
+            .unwrap(); // cannot fail with size 0
+
+        sg_raw.set_timeout(Self::SCSI_TAPE_DEFAULT_TIMEOUT);
+        let mut cmd = Vec::new();
+        cmd.push(0x08); // READ
+        cmd.push(0x02); // VARIABLE SIZED BLOCKS, SILI=1
+        //cmd.push(0x00); // VARIABLE SIZED BLOCKS, SILI=0
+        cmd.push(((transfer_len >> 16) & 0xff) as u8);
+        cmd.push(((transfer_len >> 8) & 0xff) as u8);
+        cmd.push((transfer_len & 0xff) as u8);
+        cmd.push(0); // control byte
+
+        let data = match sg_raw.do_in_command(&cmd, buffer) {
+            Ok(data) => data,
+            Err(ScsiError::Sense(SenseInfo { sense_key: 0, asc: 0, ascq: 1 })) => {
+                return Ok(BlockReadStatus::EndOfFile);
+            }
+            Err(ScsiError::Sense(SenseInfo { sense_key: 8, asc: 0, ascq: 5 })) => {
+                return Ok(BlockReadStatus::EndOfStream);
+            }
+            Err(err) => {
+                println!("READ ERR {:?}", err);
+                proxmox::io_bail!("read failed - {}", err);
+            }
+        };
+
+        if data.len() != transfer_len {
+            proxmox::io_bail!("read failed - unexpected block len ({} != {})", data.len(), buffer.len())
+        }
+
+        Ok(BlockReadStatus::Ok(transfer_len))
+    }
+
+    pub fn open_writer(&mut self) -> BlockedWriter<SgTapeWriter> {
+        let writer = SgTapeWriter::new(self);
+        BlockedWriter::new(writer)
+    }
+
+    pub fn open_reader(&mut self) -> Result<Option<BlockedReader<SgTapeReader>>, std::io::Error> {
+        let reader = SgTapeReader::new(self);
+        match BlockedReader::open(reader)? {
+            Some(reader) => Ok(Some(reader)),
+            None => Ok(None),
+        }
+    }
+}
+
+pub struct SgTapeReader<'a> {
+    sg_tape: &'a mut SgTape,
+}
+
+impl <'a> SgTapeReader<'a> {
+
+    pub fn new(sg_tape: &'a mut SgTape) -> Self {
+        Self { sg_tape }
+    }
+}
+
+impl <'a> BlockRead for SgTapeReader<'a> {
+
+    fn read_block(&mut self, buffer: &mut [u8]) -> Result<BlockReadStatus, std::io::Error> {
+        self.sg_tape.read_block(buffer)
+    }
+}
+
+pub struct SgTapeWriter<'a> {
+    sg_tape: &'a mut SgTape,
+    _leom_sent: bool,
+}
+
+impl <'a> SgTapeWriter<'a> {
+
+    pub fn new(sg_tape: &'a mut SgTape) -> Self {
+        Self { sg_tape, _leom_sent: false }
+    }
+}
+
+impl <'a> BlockWrite for SgTapeWriter<'a> {
+
+    fn write_block(&mut self, buffer: &[u8]) -> Result<bool, std::io::Error> {
+        self.sg_tape.write_block(buffer)
+    }
+
+    fn write_filemark(&mut self) -> Result<(), std::io::Error> {
+        self.sg_tape.write_filemarks(1, true)
+    }
+}