git.bitcoin.ninja 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         println!("VMW: entries in dir:");
  47         let dir_perms = fs::metadata(path.clone()).unwrap().permissions();
  48         println!("VMW: dir perms: {:?}, readonly: {}", dir_perms, dir_perms.readonly());
  49         let dir = PathBuf::from(path.clone());
  50         for entry in fs::read_dir(dir).unwrap() {
  51                 let entry = entry.unwrap();
  52                 let metadata = entry.metadata().unwrap();
  53                 println!("VMW: entry in dir: {:?}, perms in entry: {:?}, readonly: {}", entry.path(), metadata.permissions(), metadata.permissions().readonly());
  54         }
  55         // Do a crazy dance with lots of fsync()s to be overly cautious here...
  56         // We never want to end up in a state where we've lost the old data, or end up using the
  57         // old data on power loss after we've returned.
  58         // The way to atomically write a file on Unix platforms is:
  59         // open(tmpname), write(tmpfile), fsync(tmpfile), close(tmpfile), rename(), fsync(dir)
  60         let filename_with_path = get_full_filepath(path.clone(), filename);
  61         let tmp_filename = format!("{}.tmp", filename_with_path);
  62
  63         {
  64                 // Note that going by rust-lang/rust@d602a6b, on MacOS it is only safe to use
  65                 // rust stdlib 1.36 or higher.
  66                 println!("VMW: about to create file");
  67                 let mut f = fs::File::create(&tmp_filename)?;
  68                 println!("VMW: created file");
  69                 data.write_to_file(&mut f)?;
  70                 println!("VMW: about to sync all");
  71                 f.sync_all()?;
  72                 println!("VMW: sync'd all");
  73         }
  74         // Fsync the parent directory on Unix.
  75         #[cfg(not(target_os = "windows"))]
  76         {
  77                 fs::rename(&tmp_filename, &filename_with_path)?;
  78                 let path = Path::new(&filename_with_path).parent().unwrap();
  79                 let dir_file = fs::OpenOptions::new().read(true).open(path)?;
  80                 unsafe { libc::fsync(dir_file.as_raw_fd()); }
  81         }
  82         #[cfg(target_os = "windows")]
  83         {
  84                 let mut dir_perms = fs::metadata(path.clone()).unwrap().permissions();
  85                 dir_perms.set_readonly(false);
  86                 if let Ok(metadata) = fs::metadata(filename_with_path.clone()) {
  87                         let mut perms = metadata.permissions();
  88                         perms.set_readonly(false);
  89                 }
  90     // let mut perms = fs::metadata(filename_with_path.clone())?.permissions();
  91     let mut tmp_perms = fs::metadata(tmp_filename.clone())?.permissions();
  92                 tmp_perms.set_readonly(false);
  93                 println!("VMW: about to rename");
  94                 let src = PathBuf::from(tmp_filename);
  95                 let dst = PathBuf::from(filename_with_path);
  96                 call!(unsafe {winapi::um::winbase::MoveFileExW(
  97                         path_to_windows_str(src).as_ptr(), path_to_windows_str(dst).as_ptr(),
  98                         winapi::um::winbase::MOVEFILE_WRITE_THROUGH | winapi::um::winbase::MOVEFILE_REPLACE_EXISTING
  99                 )});
 100                 println!("VMW: renamed");
 101         }
 102         Ok(())
 103 }
 104
 105 #[cfg(test)]
 106 mod tests {
 107         use super::{DiskWriteable, get_full_filepath, write_to_file};
 108         use std::fs;
 109         use std::io;
 110         use std::io::Write;
 111
 112         struct TestWriteable{}
 113         impl DiskWriteable for TestWriteable {
 114                 fn write_to_file(&self, writer: &mut fs::File) -> Result<(), io::Error> {
 115                         writer.write_all(&[42; 1])
 116                 }
 117         }
 118
 119         // Test that if the persister's path to channel data is read-only, writing
 120         // data to it fails. Windows ignores the read-only flag for folders, so this
 121         // test is Unix-only.
 122         #[cfg(not(target_os = "windows"))]
 123         #[test]
 124         fn test_readonly_dir() {
 125                 let test_writeable = TestWriteable{};
 126                 let filename = "test_readonly_dir_persister_filename".to_string();
 127                 let path = "test_readonly_dir_persister_dir";
 128                 fs::create_dir_all(path.to_string()).unwrap();
 129                 let mut perms = fs::metadata(path.to_string()).unwrap().permissions();
 130                 perms.set_readonly(true);
 131                 fs::set_permissions(path.to_string(), perms).unwrap();
 132                 match write_to_file(path.to_string(), filename, &test_writeable) {
 133                         Err(e) => assert_eq!(e.kind(), io::ErrorKind::PermissionDenied),
 134                         _ => panic!("Unexpected error message")
 135                 }
 136         }
 137
 138         // Test failure to rename in the process of atomically creating a channel
 139         // monitor's file. We induce this failure by making the `tmp` file a
 140         // directory.
 141         // Explanation: given "from" = the file being renamed, "to" = the
 142         // renamee that already exists: Windows should fail because it'll fail
 143         // whenever "to" is a directory, and Unix should fail because if "from" is a
 144         // file, then "to" is also required to be a file.
 145         #[test]
 146         fn test_rename_failure() {
 147                 let test_writeable = TestWriteable{};
 148                 let filename = "test_rename_failure_filename";
 149                 let path = "test_rename_failure_dir";
 150                 // Create the channel data file and make it a directory.
 151                 fs::create_dir_all(get_full_filepath(path.to_string(), filename.to_string())).unwrap();
 152                 match write_to_file(path.to_string(), filename.to_string(), &test_writeable) {
 153                         Err(e) => {
 154                                 #[cfg(not(target_os = "windows"))]
 155                                 assert_eq!(e.kind(), io::ErrorKind::Other);
 156                                 #[cfg(target_os = "windows")]
 157                                 assert_eq!(e.kind(), io::ErrorKind::PermissionDenied);
 158                         }
 159                         _ => panic!("Unexpected error message")
 160                 }
 161                 fs::remove_dir_all(path).unwrap();
 162         }
 163
 164         #[test]
 165         fn test_diskwriteable_failure() {
 166                 struct FailingWriteable {}
 167                 impl DiskWriteable for FailingWriteable {
 168                         fn write_to_file(&self, _writer: &mut fs::File) -> Result<(), std::io::Error> {
 169                                 Err(std::io::Error::new(std::io::ErrorKind::Other, "expected failure"))
 170                         }
 171                 }
 172
 173                 let filename = "test_diskwriteable_failure";
 174                 let path = "test_diskwriteable_failure_dir";
 175                 let test_writeable = FailingWriteable{};
 176                 match write_to_file(path.to_string(), filename.to_string(), &test_writeable) {
 177                         Err(e) => {
 178                                 assert_eq!(e.kind(), std::io::ErrorKind::Other);
 179                                 assert_eq!(e.get_ref().unwrap().to_string(), "expected failure");
 180                         },
 181                         _ => panic!("unexpected result")
 182                 }
 183                 fs::remove_dir_all(path).unwrap();
 184         }
 185
 186         // Test failure to create the temporary file in the persistence process.
 187         // We induce this failure by having the temp file already exist and be a
 188         // directory.
 189         #[test]
 190         fn test_tmp_file_creation_failure() {
 191                 let test_writeable = TestWriteable{};
 192                 let filename = "test_tmp_file_creation_failure_filename".to_string();
 193                 let path = "test_tmp_file_creation_failure_dir".to_string();
 194
 195                 // Create the tmp file and make it a directory.
 196                 let tmp_path = get_full_filepath(path.clone(), format!("{}.tmp", filename.clone()));
 197                 fs::create_dir_all(tmp_path).unwrap();
 198                 match write_to_file(path, filename, &test_writeable) {
 199                         Err(e) => {
 200                                 #[cfg(not(target_os = "windows"))]
 201                                 assert_eq!(e.kind(), io::ErrorKind::Other);
 202                                 #[cfg(target_os = "windows")]
 203                                 assert_eq!(e.kind(), io::ErrorKind::PermissionDenied);
 204                         }
 205                         _ => panic!("Unexpected error message")
 206                 }
 207         }
 208 }