From: Valentine Wallace Date: Thu, 19 Nov 2020 16:26:21 +0000 (-0500) Subject: Abstract out disk-writing utilities from FilesystemPersister X-Git-Url: http://git.bitcoin.ninja/?a=commitdiff_plain;h=90ea66cf44a72275f4937a243b23a0cf51f2765f;p=rust-lightning Abstract out disk-writing utilities from FilesystemPersister --- diff --git a/lightning-persister/src/lib.rs b/lightning-persister/src/lib.rs index 7307ef0d1..da5cba95e 100644 --- a/lightning-persister/src/lib.rs +++ b/lightning-persister/src/lib.rs @@ -1,8 +1,11 @@ +mod util; + extern crate lightning; extern crate bitcoin; extern crate libc; use bitcoin::hashes::hex::ToHex; +use crate::util::DiskWriteable; use lightning::chain::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateErr}; use lightning::chain::channelmonitor; use lightning::chain::keysinterface::ChannelKeys; @@ -10,7 +13,6 @@ use lightning::chain::transaction::OutPoint; use lightning::util::ser::Writeable; use std::fs; use std::io::Error; -use std::path::{Path, PathBuf}; #[cfg(test)] use { @@ -22,9 +24,6 @@ use { std::io::Cursor }; -#[cfg(not(target_os = "windows"))] -use std::os::unix::io::AsRawFd; - /// FilesystemPersister persists channel data on disk, where each channel's /// data is stored in a file named after its funding outpoint. /// @@ -41,13 +40,9 @@ pub struct FilesystemPersister { path_to_channel_data: String, } -trait DiskWriteable { - fn write(&self, writer: &mut fs::File) -> Result<(), Error>; -} - impl DiskWriteable for ChannelMonitor { - fn write(&self, writer: &mut fs::File) -> Result<(), Error> { - Writeable::write(self, writer) + fn write_to_file(&self, writer: &mut fs::File) -> Result<(), Error> { + self.write(writer) } } @@ -60,41 +55,6 @@ impl FilesystemPersister { } } - fn get_full_filepath(&self, funding_txo: OutPoint) -> String { - let mut path = PathBuf::from(&self.path_to_channel_data); - path.push(format!("{}_{}", funding_txo.txid.to_hex(), funding_txo.index)); - path.to_str().unwrap().to_string() - } - - // Utility to write a file to disk. - fn write_channel_data(&self, funding_txo: OutPoint, monitor: &dyn DiskWriteable) -> std::io::Result<()> { - fs::create_dir_all(&self.path_to_channel_data)?; - // Do a crazy dance with lots of fsync()s to be overly cautious here... - // We never want to end up in a state where we've lost the old data, or end up using the - // old data on power loss after we've returned. - // The way to atomically write a file on Unix platforms is: - // open(tmpname), write(tmpfile), fsync(tmpfile), close(tmpfile), rename(), fsync(dir) - let filename = self.get_full_filepath(funding_txo); - let tmp_filename = format!("{}.tmp", filename.clone()); - - { - // Note that going by rust-lang/rust@d602a6b, on MacOS it is only safe to use - // rust stdlib 1.36 or higher. - let mut f = fs::File::create(&tmp_filename)?; - monitor.write(&mut f)?; - f.sync_all()?; - } - fs::rename(&tmp_filename, &filename)?; - // Fsync the parent directory on Unix. - #[cfg(not(target_os = "windows"))] - { - let path = Path::new(&filename).parent().unwrap(); - let dir_file = fs::OpenOptions::new().read(true).open(path)?; - unsafe { libc::fsync(dir_file.as_raw_fd()); } - } - Ok(()) - } - #[cfg(test)] fn load_channel_data(&self, keys: &Keys) -> Result>, ChannelMonitorUpdateErr> { @@ -132,28 +92,18 @@ impl FilesystemPersister { impl channelmonitor::Persist for FilesystemPersister { fn persist_new_channel(&self, funding_txo: OutPoint, monitor: &ChannelMonitor) -> Result<(), ChannelMonitorUpdateErr> { - self.write_channel_data(funding_txo, monitor) + let filename = format!("{}_{}", funding_txo.txid.to_hex(), funding_txo.index); + util::write_to_file(self.path_to_channel_data.clone(), filename, monitor) .map_err(|_| ChannelMonitorUpdateErr::PermanentFailure) } fn update_persisted_channel(&self, funding_txo: OutPoint, _update: &ChannelMonitorUpdate, monitor: &ChannelMonitor) -> Result<(), ChannelMonitorUpdateErr> { - self.write_channel_data(funding_txo, monitor) + let filename = format!("{}_{}", funding_txo.txid.to_hex(), funding_txo.index); + util::write_to_file(self.path_to_channel_data.clone(), filename, monitor) .map_err(|_| ChannelMonitorUpdateErr::PermanentFailure) } } -#[cfg(test)] -impl Drop for FilesystemPersister { - fn drop(&mut self) { - // We test for invalid directory names, so it's OK if directory removal - // fails. - match fs::remove_dir_all(&self.path_to_channel_data) { - Err(e) => println!("Failed to remove test persister directory: {}", e), - _ => {} - } - } -} - #[cfg(test)] mod tests { extern crate lightning; @@ -162,8 +112,6 @@ mod tests { use bitcoin::blockdata::block::{Block, BlockHeader}; use bitcoin::hashes::hex::FromHex; use bitcoin::Txid; - use DiskWriteable; - use Error; use lightning::chain::channelmonitor::{Persist, ChannelMonitorUpdateErr}; use lightning::chain::transaction::OutPoint; use lightning::{check_closed_broadcast, check_added_monitors}; @@ -171,20 +119,22 @@ mod tests { use lightning::ln::functional_test_utils::*; use lightning::ln::msgs::ErrorAction; use lightning::util::events::{MessageSendEventsProvider, MessageSendEvent}; - use lightning::util::ser::Writer; use lightning::util::test_utils; use std::fs; - use std::io; #[cfg(target_os = "windows")] use { lightning::get_event_msg, lightning::ln::msgs::ChannelMessageHandler, }; - struct TestWriteable{} - impl DiskWriteable for TestWriteable { - fn write(&self, writer: &mut fs::File) -> Result<(), Error> { - writer.write_all(&[42; 1]) + impl Drop for FilesystemPersister { + fn drop(&mut self) { + // We test for invalid directory names, so it's OK if directory removal + // fails. + match fs::remove_dir_all(&self.path_to_channel_data) { + Err(e) => println!("Failed to remove test persister directory: {}", e), + _ => {} + } } } @@ -256,88 +206,6 @@ mod tests { check_persisted_data!(11); } - // Test that if the persister's path to channel data is read-only, writing - // data to it fails. Windows ignores the read-only flag for folders, so this - // test is Unix-only. - #[cfg(not(target_os = "windows"))] - #[test] - fn test_readonly_dir() { - let persister = FilesystemPersister::new("test_readonly_dir_persister".to_string()); - let test_writeable = TestWriteable{}; - let test_txo = OutPoint { - txid: Txid::from_hex("8984484a580b825b9972d7adb15050b3ab624ccd731946b3eeddb92f4e7ef6be").unwrap(), - index: 0 - }; - // Create the persister's directory and set it to read-only. - let path = &persister.path_to_channel_data; - fs::create_dir_all(path).unwrap(); - let mut perms = fs::metadata(path).unwrap().permissions(); - perms.set_readonly(true); - fs::set_permissions(path, perms).unwrap(); - match persister.write_channel_data(test_txo, &test_writeable) { - Err(e) => assert_eq!(e.kind(), io::ErrorKind::PermissionDenied), - _ => panic!("Unexpected error message") - } - } - - // Test failure to rename in the process of atomically creating a channel - // monitor's file. We induce this failure by making the `tmp` file a - // directory. - // Explanation: given "from" = the file being renamed, "to" = the - // renamee that already exists: Windows should fail because it'll fail - // whenever "to" is a directory, and Unix should fail because if "from" is a - // file, then "to" is also required to be a file. - #[test] - fn test_rename_failure() { - let persister = FilesystemPersister::new("test_rename_failure".to_string()); - let test_writeable = TestWriteable{}; - let txid_hex = "8984484a580b825b9972d7adb15050b3ab624ccd731946b3eeddb92f4e7ef6be"; - let outp_idx = 0; - let test_txo = OutPoint { - txid: Txid::from_hex(txid_hex).unwrap(), - index: outp_idx, - }; - // Create the channel data file and make it a directory. - let path = &persister.path_to_channel_data; - fs::create_dir_all(format!("{}/{}_{}", path, txid_hex, outp_idx)).unwrap(); - match persister.write_channel_data(test_txo, &test_writeable) { - Err(e) => { - #[cfg(not(target_os = "windows"))] - assert_eq!(e.kind(), io::ErrorKind::Other); - #[cfg(target_os = "windows")] - assert_eq!(e.kind(), io::ErrorKind::PermissionDenied); - } - _ => panic!("Unexpected error message") - } - } - - // Test failure to create the temporary file in the persistence process. - // We induce this failure by having the temp file already exist and be a - // directory. - #[test] - fn test_tmp_file_creation_failure() { - let persister = FilesystemPersister::new("test_tmp_file_creation_failure".to_string()); - let test_writeable = TestWriteable{}; - let txid_hex = "8984484a580b825b9972d7adb15050b3ab624ccd731946b3eeddb92f4e7ef6be"; - let outp_idx = 0; - let test_txo = OutPoint { - txid: Txid::from_hex(txid_hex).unwrap(), - index: outp_idx, - }; - // Create the tmp file and make it a directory. - let path = &persister.path_to_channel_data; - fs::create_dir_all(format!("{}/{}_{}.tmp", path, txid_hex, outp_idx)).unwrap(); - match persister.write_channel_data(test_txo, &test_writeable) { - Err(e) => { - #[cfg(not(target_os = "windows"))] - assert_eq!(e.kind(), io::ErrorKind::Other); - #[cfg(target_os = "windows")] - assert_eq!(e.kind(), io::ErrorKind::PermissionDenied); - } - _ => panic!("Unexpected error message") - } - } - // Test that if the persister's path to channel data is read-only, writing a // monitor to it results in the persister returning a PermanentFailure. // Windows ignores the read-only flag for folders, so this test is Unix-only. diff --git a/lightning-persister/src/util.rs b/lightning-persister/src/util.rs new file mode 100644 index 000000000..0e3999883 --- /dev/null +++ b/lightning-persister/src/util.rs @@ -0,0 +1,149 @@ +use std::fs; +use std::path::{Path, PathBuf}; + +#[cfg(not(target_os = "windows"))] +use std::os::unix::io::AsRawFd; + +pub(crate) trait DiskWriteable { + fn write_to_file(&self, writer: &mut fs::File) -> Result<(), std::io::Error>; +} + +pub fn get_full_filepath(filepath: String, filename: String) -> String { + let mut path = PathBuf::from(filepath); + path.push(filename); + path.to_str().unwrap().to_string() +} + +#[allow(bare_trait_objects)] +pub(crate) fn write_to_file(path: String, filename: String, data: &D) -> std::io::Result<()> { + fs::create_dir_all(path.clone())?; + // Do a crazy dance with lots of fsync()s to be overly cautious here... + // We never want to end up in a state where we've lost the old data, or end up using the + // old data on power loss after we've returned. + // The way to atomically write a file on Unix platforms is: + // open(tmpname), write(tmpfile), fsync(tmpfile), close(tmpfile), rename(), fsync(dir) + let filename_with_path = get_full_filepath(path, filename); + let tmp_filename = format!("{}.tmp", filename_with_path); + + { + // Note that going by rust-lang/rust@d602a6b, on MacOS it is only safe to use + // rust stdlib 1.36 or higher. + let mut f = fs::File::create(&tmp_filename)?; + data.write_to_file(&mut f)?; + f.sync_all()?; + } + fs::rename(&tmp_filename, &filename_with_path)?; + // Fsync the parent directory on Unix. + #[cfg(not(target_os = "windows"))] + { + let path = Path::new(&filename_with_path).parent().unwrap(); + let dir_file = fs::OpenOptions::new().read(true).open(path)?; + unsafe { libc::fsync(dir_file.as_raw_fd()); } + } + Ok(()) +} + +#[cfg(test)] +mod tests { + use super::{DiskWriteable, get_full_filepath, write_to_file}; + use std::fs; + use std::io; + use std::io::Write; + + struct TestWriteable{} + impl DiskWriteable for TestWriteable { + fn write_to_file(&self, writer: &mut fs::File) -> Result<(), io::Error> { + writer.write_all(&[42; 1]) + } + } + + // Test that if the persister's path to channel data is read-only, writing + // data to it fails. Windows ignores the read-only flag for folders, so this + // test is Unix-only. + #[cfg(not(target_os = "windows"))] + #[test] + fn test_readonly_dir() { + let test_writeable = TestWriteable{}; + let filename = "test_readonly_dir_persister_filename".to_string(); + let path = "test_readonly_dir_persister_dir"; + fs::create_dir_all(path.to_string()).unwrap(); + let mut perms = fs::metadata(path.to_string()).unwrap().permissions(); + perms.set_readonly(true); + fs::set_permissions(path.to_string(), perms).unwrap(); + match write_to_file(path.to_string(), filename, &test_writeable) { + Err(e) => assert_eq!(e.kind(), io::ErrorKind::PermissionDenied), + _ => panic!("Unexpected error message") + } + } + + // Test failure to rename in the process of atomically creating a channel + // monitor's file. We induce this failure by making the `tmp` file a + // directory. + // Explanation: given "from" = the file being renamed, "to" = the + // renamee that already exists: Windows should fail because it'll fail + // whenever "to" is a directory, and Unix should fail because if "from" is a + // file, then "to" is also required to be a file. + #[test] + fn test_rename_failure() { + let test_writeable = TestWriteable{}; + let filename = "test_rename_failure_filename"; + let path = "test_rename_failure_dir"; + // Create the channel data file and make it a directory. + fs::create_dir_all(get_full_filepath(path.to_string(), filename.to_string())).unwrap(); + match write_to_file(path.to_string(), filename.to_string(), &test_writeable) { + Err(e) => { + #[cfg(not(target_os = "windows"))] + assert_eq!(e.kind(), io::ErrorKind::Other); + #[cfg(target_os = "windows")] + assert_eq!(e.kind(), io::ErrorKind::PermissionDenied); + } + _ => panic!("Unexpected error message") + } + fs::remove_dir_all(path).unwrap(); + } + + #[test] + fn test_diskwriteable_failure() { + struct FailingWriteable {} + impl DiskWriteable for FailingWriteable { + fn write_to_file(&self, _writer: &mut fs::File) -> Result<(), std::io::Error> { + Err(std::io::Error::new(std::io::ErrorKind::Other, "expected failure")) + } + } + + let filename = "test_diskwriteable_failure"; + let path = "test_diskwriteable_failure_dir"; + let test_writeable = FailingWriteable{}; + match write_to_file(path.to_string(), filename.to_string(), &test_writeable) { + Err(e) => { + assert_eq!(e.kind(), std::io::ErrorKind::Other); + assert_eq!(e.get_ref().unwrap().to_string(), "expected failure"); + }, + _ => panic!("unexpected result") + } + fs::remove_dir_all(path).unwrap(); + } + + // Test failure to create the temporary file in the persistence process. + // We induce this failure by having the temp file already exist and be a + // directory. + #[test] + fn test_tmp_file_creation_failure() { + let test_writeable = TestWriteable{}; + let filename = "test_tmp_file_creation_failure_filename".to_string(); + let path = "test_tmp_file_creation_failure_dir".to_string(); + + // Create the tmp file and make it a directory. + let tmp_path = get_full_filepath(path.clone(), format!("{}.tmp", filename.clone())); + fs::create_dir_all(tmp_path).unwrap(); + match write_to_file(path, filename, &test_writeable) { + Err(e) => { + #[cfg(not(target_os = "windows"))] + assert_eq!(e.kind(), io::ErrorKind::Other); + #[cfg(target_os = "windows")] + assert_eq!(e.kind(), io::ErrorKind::PermissionDenied); + } + _ => panic!("Unexpected error message") + } + } +}