_ Git - rust-lightning/blob - lightning-persister/src/util.rs

   1
   2 #[cfg(target_os = "windows")]
   3 extern crate winapi;
   4
   5 use std::fs;
   6 use std::path::{Path, PathBuf};
   7 #[cfg(target_os = "windows")]
   8         use {
   9                 std::ffi::OsStr,
  10                 std::os::windows::ffi::OsStrExt
  11                 };
  12 #[cfg(not(target_os = "windows"))]
  13 use std::os::unix::io::AsRawFd;
  14
  15 pub(crate) trait DiskWriteable {
  16         fn write_to_file(&self, writer: &mut fs::File) -> Result<(), std::io::Error>;
  17 }
  18
  19 pub(crate) fn get_full_filepath(filepath: String, filename: String) -> String {
  20         let mut path = PathBuf::from(filepath);
  21         path.push(filename);
  22         path.to_str().unwrap().to_string()
  23 }
  24 #[cfg(target_os = "windows")]
  25 macro_rules! call {
  26         ($e: expr) => (
  27                 if $e != 0 {
  28                         return Ok(())
  29                 } else {
  30                         return Err(std::io::Error::last_os_error())
  31                 }
  32         )
  33 }
  34
  35 #[cfg(target_os = "windows")]
  36 fn path_to_windows_str<T: AsRef<OsStr>>(x: T) -> Vec<winapi::shared::ntdef::WCHAR> {
  37         x.as_ref().encode_wide().chain(Some(0)).collect()
  38 }
  39
  40 #[allow(bare_trait_objects)]
  41 pub(crate) fn write_to_file<D: DiskWriteable>(path: String, filename: String, data: &D) -> std::io::Result<()> {
  42         println!("VMW: creating dir");
  43         fs::create_dir_all(path.clone())?;
  44         println!("VMW: created dir");
  45
  46         // Do a crazy dance with lots of fsync()s to be overly cautious here...
  47         // We never want to end up in a state where we've lost the old data, or end up using the
  48         // old data on power loss after we've returned.
  49         // The way to atomically write a file on Unix platforms is:
  50         // open(tmpname), write(tmpfile), fsync(tmpfile), close(tmpfile), rename(), fsync(dir)
  51         let filename_with_path = get_full_filepath(path.clone(), filename);
  52         let tmp_filename = format!("{}.tmp", filename_with_path);
  53
  54         {
  55                 // Note that going by rust-lang/rust@d602a6b, on MacOS it is only safe to use
  56                 // rust stdlib 1.36 or higher.
  57                 println!("VMW: about to create file");
  58                 let mut f = fs::File::create(&tmp_filename)?;
  59                 println!("VMW: created file");
  60                 data.write_to_file(&mut f)?;
  61                 println!("VMW: about to sync all");
  62                 f.sync_all()?;
  63                 println!("VMW: sync'd all");
  64         }
  65         // Fsync the parent directory on Unix.
  66         #[cfg(not(target_os = "windows"))]
  67         {
  68                 fs::rename(&tmp_filename, &filename_with_path)?;
  69                 let path = Path::new(&filename_with_path).parent().unwrap();
  70                 let dir_file = fs::OpenOptions::new().read(true).open(path)?;
  71                 unsafe { libc::fsync(dir_file.as_raw_fd()); }
  72         }
  73         // std::thread::sleep(std::time::Duration::new(60, 0));
  74         #[cfg(target_os = "windows")]
  75         {
  76                 println!("VMW: entries in dir:");
  77                 let dir_perms = fs::metadata(path.clone()).unwrap().permissions();
  78                 println!("VMW: dir perms: {:?}, readonly: {}", dir_perms, dir_perms.readonly());
  79                 let dir = PathBuf::from(path.clone());
  80                 for entry in fs::read_dir(dir).unwrap() {
  81                         let entry = entry.unwrap();
  82                         let metadata = entry.metadata().unwrap();
  83                         println!("VMW: entry in dir: {:?}, perms in entry: {:?}, readonly: {}", entry.path(), metadata.permissions(), metadata.permissions().readonly());
  84                 }
  85
  86                 // let mut dir_perms = fs::metadata(path.clone()).unwrap().permissions();
  87                 // dir_perms.set_readonly(false);
  88                 // if let Ok(metadata) = fs::metadata(filename_with_path.clone()) {
  89                 //      let mut perms = metadata.permissions();
  90                 //      perms.set_readonly(false);
  91                 // }
  92     // // let mut perms = fs::metadata(filename_with_path.clone())?.permissions();
  93     // let mut tmp_perms = fs::metadata(tmp_filename.clone())?.permissions();
  94                 // tmp_perms.set_readonly(false);
  95                 // println!("VMW: about to rename");
  96                 let src = PathBuf::from(tmp_filename.clone());
  97                 let dst = PathBuf::from(filename_with_path.clone());
  98                 // fs::rename(&tmp_filename.clone(), &filename_with_path.clone())?;
  99                 // call!(unsafe {winapi::um::winbase::MoveFileExW(
 100                 //      path_to_windows_str(src).as_ptr(), path_to_windows_str(dst).as_ptr(),
 101                 //      winapi::um::winbase::MOVEFILE_WRITE_THROUGH | winapi::um::winbase::MOVEFILE_REPLACE_EXISTING
 102                 // )});
 103                 let backup_filepath = PathBuf::from(format!("{}.backup", filename_with_path.clone()));
 104
 105                 if Path::new(&filename_with_path.clone()).exists() {
 106                         unsafe {winapi::um::winbase::ReplaceFileW(
 107                                 path_to_windows_str(src).as_ptr(), path_to_windows_str(dst).as_ptr(), path_to_windows_str(backup_filepath).as_ptr(),
 108                                 winapi::um::winbase::REPLACEFILE_IGNORE_MERGE_ERRORS, std::ptr::null_mut() as *mut winapi::ctypes::c_void, std::ptr::null_mut() as *mut winapi::ctypes::c_void
 109                         )};
 110                 } else {
 111                         call!(unsafe {winapi::um::winbase::MoveFileExW(
 112                                 path_to_windows_str(src).as_ptr(), path_to_windows_str(dst).as_ptr(),
 113                                 winapi::um::winbase::MOVEFILE_WRITE_THROUGH | winapi::um::winbase::MOVEFILE_REPLACE_EXISTING
 114                         )});
 115                 }
 116                 println!("VMW: renamed");
 117         }
 118         Ok(())
 119 }
 120
 121 #[cfg(test)]
 122 mod tests {
 123         use super::{DiskWriteable, get_full_filepath, write_to_file};
 124         use std::fs;
 125         use std::io;
 126         use std::io::Write;
 127
 128         struct TestWriteable{}
 129         impl DiskWriteable for TestWriteable {
 130                 fn write_to_file(&self, writer: &mut fs::File) -> Result<(), io::Error> {
 131                         writer.write_all(&[42; 1])
 132                 }
 133         }
 134
 135         // Test that if the persister's path to channel data is read-only, writing
 136         // data to it fails. Windows ignores the read-only flag for folders, so this
 137         // test is Unix-only.
 138         #[cfg(not(target_os = "windows"))]
 139         #[test]
 140         fn test_readonly_dir() {
 141                 let test_writeable = TestWriteable{};
 142                 let filename = "test_readonly_dir_persister_filename".to_string();
 143                 let path = "test_readonly_dir_persister_dir";
 144                 fs::create_dir_all(path.to_string()).unwrap();
 145                 let mut perms = fs::metadata(path.to_string()).unwrap().permissions();
 146                 perms.set_readonly(true);
 147                 fs::set_permissions(path.to_string(), perms).unwrap();
 148                 match write_to_file(path.to_string(), filename, &test_writeable) {
 149                         Err(e) => assert_eq!(e.kind(), io::ErrorKind::PermissionDenied),
 150                         _ => panic!("Unexpected error message")
 151                 }
 152         }
 153
 154         // Test failure to rename in the process of atomically creating a channel
 155         // monitor's file. We induce this failure by making the `tmp` file a
 156         // directory.
 157         // Explanation: given "from" = the file being renamed, "to" = the
 158         // renamee that already exists: Windows should fail because it'll fail
 159         // whenever "to" is a directory, and Unix should fail because if "from" is a
 160         // file, then "to" is also required to be a file.
 161         #[test]
 162         fn test_rename_failure() {
 163                 let test_writeable = TestWriteable{};
 164                 let filename = "test_rename_failure_filename";
 165                 let path = "test_rename_failure_dir";
 166                 // Create the channel data file and make it a directory.
 167                 fs::create_dir_all(get_full_filepath(path.to_string(), filename.to_string())).unwrap();
 168                 match write_to_file(path.to_string(), filename.to_string(), &test_writeable) {
 169                         Err(e) => {
 170                                 #[cfg(not(target_os = "windows"))]
 171                                 assert_eq!(e.kind(), io::ErrorKind::Other);
 172                                 #[cfg(target_os = "windows")]
 173                                 assert_eq!(e.kind(), io::ErrorKind::PermissionDenied);
 174                         }
 175                         _ => panic!("Unexpected error message")
 176                 }
 177                 fs::remove_dir_all(path).unwrap();
 178         }
 179
 180         #[test]
 181         fn test_diskwriteable_failure() {
 182                 struct FailingWriteable {}
 183                 impl DiskWriteable for FailingWriteable {
 184                         fn write_to_file(&self, _writer: &mut fs::File) -> Result<(), std::io::Error> {
 185                                 Err(std::io::Error::new(std::io::ErrorKind::Other, "expected failure"))
 186                         }
 187                 }
 188
 189                 let filename = "test_diskwriteable_failure";
 190                 let path = "test_diskwriteable_failure_dir";
 191                 let test_writeable = FailingWriteable{};
 192                 match write_to_file(path.to_string(), filename.to_string(), &test_writeable) {
 193                         Err(e) => {
 194                                 assert_eq!(e.kind(), std::io::ErrorKind::Other);
 195                                 assert_eq!(e.get_ref().unwrap().to_string(), "expected failure");
 196                         },
 197                         _ => panic!("unexpected result")
 198                 }
 199                 fs::remove_dir_all(path).unwrap();
 200         }
 201
 202         // Test failure to create the temporary file in the persistence process.
 203         // We induce this failure by having the temp file already exist and be a
 204         // directory.
 205         #[test]
 206         fn test_tmp_file_creation_failure() {
 207                 let test_writeable = TestWriteable{};
 208                 let filename = "test_tmp_file_creation_failure_filename".to_string();
 209                 let path = "test_tmp_file_creation_failure_dir".to_string();
 210
 211                 // Create the tmp file and make it a directory.
 212                 let tmp_path = get_full_filepath(path.clone(), format!("{}.tmp", filename.clone()));
 213                 fs::create_dir_all(tmp_path).unwrap();
 214                 match write_to_file(path, filename, &test_writeable) {
 215                         Err(e) => {
 216                                 #[cfg(not(target_os = "windows"))]
 217                                 assert_eq!(e.kind(), io::ErrorKind::Other);
 218                                 #[cfg(target_os = "windows")]
 219                                 assert_eq!(e.kind(), io::ErrorKind::PermissionDenied);
 220                         }
 221                         _ => panic!("Unexpected error message")
 222                 }
 223         }
 224 }