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