From 33c06b3388edc6e51832c961fa9569fbc87effc4 Mon Sep 17 00:00:00 2001 From: Dominik Csapak Date: Thu, 18 Feb 2021 15:40:20 +0100 Subject: [PATCH] tape/drive: add test_device_path_lock this makes it possible to detect if the drive was locked in a non-blocking manner Signed-off-by: Dominik Csapak --- src/tape/drive/mod.rs | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/src/tape/drive/mod.rs b/src/tape/drive/mod.rs index e44e0e36..faa89953 100644 --- a/src/tape/drive/mod.rs +++ b/src/tape/drive/mod.rs @@ -496,3 +496,28 @@ fn lock_device_path(device_path: &str) -> Result { Ok(DeviceLockGuard(file)) } + +// Same logic as lock_device_path, but uses a timeout of 0, making it +// non-blocking, and returning if the file is locked or not +fn test_device_path_lock(device_path: &str) -> Result { + + let lock_name = crate::tools::systemd::escape_unit(device_path, true); + + let mut path = std::path::PathBuf::from("/var/lock"); + path.push(lock_name); + + let timeout = std::time::Duration::new(0, 0); + let mut file = std::fs::OpenOptions::new().create(true).append(true).open(path)?; + match proxmox::tools::fs::lock_file(&mut file, true, Some(timeout)) { + // file was not locked, continue + Ok(()) => {}, + // file was locked, return true + Err(err) if err.kind() == std::io::ErrorKind::WouldBlock => return Ok(true), + Err(err) => bail!("{}", err), + } + + let backup_user = crate::backup::backup_user()?; + fchown(file.as_raw_fd(), Some(backup_user.uid), Some(backup_user.gid))?; + + Ok(false) +}