1 #[cfg(target_os = "windows")]
5 use std::path::{Path, PathBuf};
7 #[cfg(not(target_os = "windows"))]
8 use std::os::unix::io::AsRawFd;
10 #[cfg(target_os = "windows")]
13 std::os::windows::ffi::OsStrExt
16 pub(crate) trait DiskWriteable {
17 fn write_to_file(&self, writer: &mut fs::File) -> Result<(), std::io::Error>;
20 pub(crate) fn get_full_filepath(mut filepath: PathBuf, filename: String) -> String {
21 filepath.push(filename);
22 filepath.to_str().unwrap().to_string()
25 #[cfg(target_os = "windows")]
31 return Err(std::io::Error::last_os_error())
36 #[cfg(target_os = "windows")]
37 fn path_to_windows_str<T: AsRef<OsStr>>(path: T) -> Vec<winapi::shared::ntdef::WCHAR> {
38 path.as_ref().encode_wide().chain(Some(0)).collect()
41 #[allow(bare_trait_objects)]
42 pub(crate) fn write_to_file<D: DiskWriteable>(path: PathBuf, filename: String, data: &D) -> std::io::Result<()> {
43 fs::create_dir_all(path.clone())?;
44 // Do a crazy dance with lots of fsync()s to be overly cautious here...
45 // We never want to end up in a state where we've lost the old data, or end up using the
46 // old data on power loss after we've returned.
47 // The way to atomically write a file on Unix platforms is:
48 // open(tmpname), write(tmpfile), fsync(tmpfile), close(tmpfile), rename(), fsync(dir)
49 let filename_with_path = get_full_filepath(path, filename);
50 let tmp_filename = format!("{}.tmp", filename_with_path.clone());
53 // Note that going by rust-lang/rust@d602a6b, on MacOS it is only safe to use
54 // rust stdlib 1.36 or higher.
55 let mut f = fs::File::create(&tmp_filename)?;
56 data.write_to_file(&mut f)?;
59 // Fsync the parent directory on Unix.
60 #[cfg(not(target_os = "windows"))]
62 fs::rename(&tmp_filename, &filename_with_path)?;
63 let path = Path::new(&filename_with_path).parent().unwrap();
64 let dir_file = fs::OpenOptions::new().read(true).open(path)?;
65 unsafe { libc::fsync(dir_file.as_raw_fd()); }
67 #[cfg(target_os = "windows")]
69 let src = PathBuf::from(tmp_filename.clone());
70 let dst = PathBuf::from(filename_with_path.clone());
71 if Path::new(&filename_with_path.clone()).exists() {
72 unsafe {winapi::um::winbase::ReplaceFileW(
73 path_to_windows_str(dst).as_ptr(), path_to_windows_str(src).as_ptr(), std::ptr::null(),
74 winapi::um::winbase::REPLACEFILE_IGNORE_MERGE_ERRORS,
75 std::ptr::null_mut() as *mut winapi::ctypes::c_void,
76 std::ptr::null_mut() as *mut winapi::ctypes::c_void
79 call!(unsafe {winapi::um::winbase::MoveFileExW(
80 path_to_windows_str(src).as_ptr(), path_to_windows_str(dst).as_ptr(),
81 winapi::um::winbase::MOVEFILE_WRITE_THROUGH | winapi::um::winbase::MOVEFILE_REPLACE_EXISTING
90 use super::{DiskWriteable, get_full_filepath, write_to_file};
94 use std::path::PathBuf;
96 struct TestWriteable{}
97 impl DiskWriteable for TestWriteable {
98 fn write_to_file(&self, writer: &mut fs::File) -> Result<(), io::Error> {
99 writer.write_all(&[42; 1])
103 // Test that if the persister's path to channel data is read-only, writing
104 // data to it fails. Windows ignores the read-only flag for folders, so this
105 // test is Unix-only.
106 #[cfg(not(target_os = "windows"))]
108 fn test_readonly_dir() {
109 let test_writeable = TestWriteable{};
110 let filename = "test_readonly_dir_persister_filename".to_string();
111 let path = "test_readonly_dir_persister_dir";
112 fs::create_dir_all(path.to_string()).unwrap();
113 let mut perms = fs::metadata(path.to_string()).unwrap().permissions();
114 perms.set_readonly(true);
115 fs::set_permissions(path.to_string(), perms).unwrap();
116 match write_to_file(PathBuf::from(path.to_string()), filename, &test_writeable) {
117 Err(e) => assert_eq!(e.kind(), io::ErrorKind::PermissionDenied),
118 _ => panic!("Unexpected error message")
122 // Test failure to rename in the process of atomically creating a channel
123 // monitor's file. We induce this failure by making the `tmp` file a
125 // Explanation: given "from" = the file being renamed, "to" = the destination
126 // file that already exists: Unix should fail because if "from" is a file,
127 // then "to" is also required to be a file.
128 // TODO: ideally try to make this work on Windows again
129 #[cfg(not(target_os = "windows"))]
131 fn test_rename_failure() {
132 let test_writeable = TestWriteable{};
133 let filename = "test_rename_failure_filename";
134 let path = PathBuf::from("test_rename_failure_dir");
135 // Create the channel data file and make it a directory.
136 fs::create_dir_all(get_full_filepath(path.clone(), filename.to_string())).unwrap();
137 match write_to_file(path.clone(), filename.to_string(), &test_writeable) {
138 Err(e) => assert_eq!(e.raw_os_error(), Some(libc::EISDIR)),
139 _ => panic!("Unexpected Ok(())")
141 fs::remove_dir_all(path).unwrap();
145 fn test_diskwriteable_failure() {
146 struct FailingWriteable {}
147 impl DiskWriteable for FailingWriteable {
148 fn write_to_file(&self, _writer: &mut fs::File) -> Result<(), std::io::Error> {
149 Err(std::io::Error::new(std::io::ErrorKind::Other, "expected failure"))
153 let filename = "test_diskwriteable_failure";
154 let path = PathBuf::from("test_diskwriteable_failure_dir");
155 let test_writeable = FailingWriteable{};
156 match write_to_file(path.clone(), filename.to_string(), &test_writeable) {
158 assert_eq!(e.kind(), std::io::ErrorKind::Other);
159 assert_eq!(e.get_ref().unwrap().to_string(), "expected failure");
161 _ => panic!("unexpected result")
163 fs::remove_dir_all(path).unwrap();
166 // Test failure to create the temporary file in the persistence process.
167 // We induce this failure by having the temp file already exist and be a
170 fn test_tmp_file_creation_failure() {
171 let test_writeable = TestWriteable{};
172 let filename = "test_tmp_file_creation_failure_filename".to_string();
173 let path = PathBuf::from("test_tmp_file_creation_failure_dir");
175 // Create the tmp file and make it a directory.
176 let tmp_path = get_full_filepath(path.clone(), format!("{}.tmp", filename.clone()));
177 fs::create_dir_all(tmp_path).unwrap();
178 match write_to_file(path, filename, &test_writeable) {
180 #[cfg(not(target_os = "windows"))]
181 assert_eq!(e.raw_os_error(), Some(libc::EISDIR));
182 #[cfg(target_os = "windows")]
183 assert_eq!(e.kind(), io::ErrorKind::PermissionDenied);
185 _ => panic!("Unexpected error message")