_ 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         #[cfg(target_os = "windows")]
  74         {
  75                 println!("VMW: entries in dir:");
  76                 let dir_perms = fs::metadata(path.clone()).unwrap().permissions();
  77                 println!("VMW: dir perms: {:?}, readonly: {}", dir_perms, dir_perms.readonly());
  78                 let dir = PathBuf::from(path.clone());
  79                 for entry in fs::read_dir(dir).unwrap() {
  80                         let entry = entry.unwrap();
  81                         let metadata = entry.metadata().unwrap();
  82                         println!("VMW: entry in dir: {:?}, perms in entry: {:?}, readonly: {}", entry.path(), metadata.permissions(), metadata.permissions().readonly());
  83                 }
  84
  85                 let mut dir_perms = fs::metadata(path.clone()).unwrap().permissions();
  86                 dir_perms.set_readonly(false);
  87                 if let Ok(metadata) = fs::metadata(filename_with_path.clone()) {
  88                         let mut perms = metadata.permissions();
  89                         perms.set_readonly(false);
  90                 }
  91     // let mut perms = fs::metadata(filename_with_path.clone())?.permissions();
  92     let mut tmp_perms = fs::metadata(tmp_filename.clone())?.permissions();
  93                 tmp_perms.set_readonly(false);
  94                 println!("VMW: about to rename");
  95                 let src = PathBuf::from(tmp_filename);
  96                 let dst = PathBuf::from(filename_with_path);
  97                 call!(unsafe {winapi::um::winbase::MoveFileExW(
  98                         path_to_windows_str(src).as_ptr(), path_to_windows_str(dst).as_ptr(),
  99                         winapi::um::winbase::MOVEFILE_WRITE_THROUGH | winapi::um::winbase::MOVEFILE_REPLACE_EXISTING
 100                 )});
 101                 println!("VMW: renamed");
 102         }
 103         Ok(())
 104 }
 105
 106 #[cfg(test)]
 107 mod tests {
 108         use super::{DiskWriteable, get_full_filepath, write_to_file};
 109         use std::fs;
 110         use std::io;
 111         use std::io::Write;
 112
 113         struct TestWriteable{}
 114         impl DiskWriteable for TestWriteable {
 115                 fn write_to_file(&self, writer: &mut fs::File) -> Result<(), io::Error> {
 116                         writer.write_all(&[42; 1])
 117                 }
 118         }
 119
 120         // Test that if the persister's path to channel data is read-only, writing
 121         // data to it fails. Windows ignores the read-only flag for folders, so this
 122         // test is Unix-only.
 123         #[cfg(not(target_os = "windows"))]
 124         #[test]
 125         fn test_readonly_dir() {
 126                 let test_writeable = TestWriteable{};
 127                 let filename = "test_readonly_dir_persister_filename".to_string();
 128                 let path = "test_readonly_dir_persister_dir";
 129                 fs::create_dir_all(path.to_string()).unwrap();
 130                 let mut perms = fs::metadata(path.to_string()).unwrap().permissions();
 131                 perms.set_readonly(true);
 132                 fs::set_permissions(path.to_string(), perms).unwrap();
 133                 match write_to_file(path.to_string(), filename, &test_writeable) {
 134                         Err(e) => assert_eq!(e.kind(), io::ErrorKind::PermissionDenied),
 135                         _ => panic!("Unexpected error message")
 136                 }
 137         }
 138
 139         // Test failure to rename in the process of atomically creating a channel
 140         // monitor's file. We induce this failure by making the `tmp` file a
 141         // directory.
 142         // Explanation: given "from" = the file being renamed, "to" = the
 143         // renamee that already exists: Windows should fail because it'll fail
 144         // whenever "to" is a directory, and Unix should fail because if "from" is a
 145         // file, then "to" is also required to be a file.
 146         #[test]
 147         fn test_rename_failure() {
 148                 let test_writeable = TestWriteable{};
 149                 let filename = "test_rename_failure_filename";
 150                 let path = "test_rename_failure_dir";
 151                 // Create the channel data file and make it a directory.
 152                 fs::create_dir_all(get_full_filepath(path.to_string(), filename.to_string())).unwrap();
 153                 match write_to_file(path.to_string(), filename.to_string(), &test_writeable) {
 154                         Err(e) => {
 155                                 #[cfg(not(target_os = "windows"))]
 156                                 assert_eq!(e.kind(), io::ErrorKind::Other);
 157                                 #[cfg(target_os = "windows")]
 158                                 assert_eq!(e.kind(), io::ErrorKind::PermissionDenied);
 159                         }
 160                         _ => panic!("Unexpected error message")
 161                 }
 162                 fs::remove_dir_all(path).unwrap();
 163         }
 164
 165         #[test]
 166         fn test_diskwriteable_failure() {
 167                 struct FailingWriteable {}
 168                 impl DiskWriteable for FailingWriteable {
 169                         fn write_to_file(&self, _writer: &mut fs::File) -> Result<(), std::io::Error> {
 170                                 Err(std::io::Error::new(std::io::ErrorKind::Other, "expected failure"))
 171                         }
 172                 }
 173
 174                 let filename = "test_diskwriteable_failure";
 175                 let path = "test_diskwriteable_failure_dir";
 176                 let test_writeable = FailingWriteable{};
 177                 match write_to_file(path.to_string(), filename.to_string(), &test_writeable) {
 178                         Err(e) => {
 179                                 assert_eq!(e.kind(), std::io::ErrorKind::Other);
 180                                 assert_eq!(e.get_ref().unwrap().to_string(), "expected failure");
 181                         },
 182                         _ => panic!("unexpected result")
 183                 }
 184                 fs::remove_dir_all(path).unwrap();
 185         }
 186
 187         // Test failure to create the temporary file in the persistence process.
 188         // We induce this failure by having the temp file already exist and be a
 189         // directory.
 190         #[test]
 191         fn test_tmp_file_creation_failure() {
 192                 let test_writeable = TestWriteable{};
 193                 let filename = "test_tmp_file_creation_failure_filename".to_string();
 194                 let path = "test_tmp_file_creation_failure_dir".to_string();
 195
 196                 // Create the tmp file and make it a directory.
 197                 let tmp_path = get_full_filepath(path.clone(), format!("{}.tmp", filename.clone()));
 198                 fs::create_dir_all(tmp_path).unwrap();
 199                 match write_to_file(path, filename, &test_writeable) {
 200                         Err(e) => {
 201                                 #[cfg(not(target_os = "windows"))]
 202                                 assert_eq!(e.kind(), io::ErrorKind::Other);
 203                                 #[cfg(target_os = "windows")]
 204                                 assert_eq!(e.kind(), io::ErrorKind::PermissionDenied);
 205                         }
 206                         _ => panic!("Unexpected error message")
 207                 }
 208         }
 209 }