library/std/src/sys/unix/ext/fs.rs

   1 //! Unix-specific extensions to primitives in the `std::fs` module.
   2
   3 #![stable(feature = "rust1", since = "1.0.0")]
   4
   5 use crate::fs::{self, OpenOptions, Permissions};
   6 use crate::io;
   7 use crate::path::Path;
   8 use crate::sys;
   9 use crate::sys::platform::fs::MetadataExt as UnixMetadataExt;
  10 use crate::sys_common::{AsInner, AsInnerMut, FromInner};
  11 // Used for `File::read` on intra-doc links
  12 #[allow(unused_imports)]
  13 use io::{Read, Write};
  14
  15 /// Unix-specific extensions to [`fs::File`].
  16 #[stable(feature = "file_offset", since = "1.15.0")]
  17 pub trait FileExt {
  18     /// Reads a number of bytes starting from a given offset.
  19     ///
  20     /// Returns the number of bytes read.
  21     ///
  22     /// The offset is relative to the start of the file and thus independent
  23     /// from the current cursor.
  24     ///
  25     /// The current file cursor is not affected by this function.
  26     ///
  27     /// Note that similar to [`File::read`], it is not an error to return with a
  28     /// short read.
  29     ///
  30     /// [`File::read`]: fs::File::read
  31     ///
  32     /// # Examples
  33     ///
  34     /// ```no_run
  35     /// use std::io;
  36     /// use std::fs::File;
  37     /// use std::os::unix::prelude::FileExt;
  38     ///
  39     /// fn main() -> io::Result<()> {
  40     ///     let mut buf = [0u8; 8];
  41     ///     let file = File::open("foo.txt")?;
  42     ///
  43     ///     // We now read 8 bytes from the offset 10.
  44     ///     let num_bytes_read = file.read_at(&mut buf, 10)?;
  45     ///     println!("read {} bytes: {:?}", num_bytes_read, buf);
  46     ///     Ok(())
  47     /// }
  48     /// ```
  49     #[stable(feature = "file_offset", since = "1.15.0")]
  50     fn read_at(&self, buf: &mut [u8], offset: u64) -> io::Result<usize>;
  51
  52     /// Reads the exact number of byte required to fill `buf` from the given offset.
  53     ///
  54     /// The offset is relative to the start of the file and thus independent
  55     /// from the current cursor.
  56     ///
  57     /// The current file cursor is not affected by this function.
  58     ///
  59     /// Similar to [`io::Read::read_exact`] but uses [`read_at`] instead of `read`.
  60     ///
  61     /// [`read_at`]: FileExt::read_at
  62     ///
  63     /// # Errors
  64     ///
  65     /// If this function encounters an error of the kind
  66     /// [`io::ErrorKind::Interrupted`] then the error is ignored and the operation
  67     /// will continue.
  68     ///
  69     /// If this function encounters an "end of file" before completely filling
  70     /// the buffer, it returns an error of the kind [`io::ErrorKind::UnexpectedEof`].
  71     /// The contents of `buf` are unspecified in this case.
  72     ///
  73     /// If any other read error is encountered then this function immediately
  74     /// returns. The contents of `buf` are unspecified in this case.
  75     ///
  76     /// If this function returns an error, it is unspecified how many bytes it
  77     /// has read, but it will never read more than would be necessary to
  78     /// completely fill the buffer.
  79     ///
  80     /// # Examples
  81     ///
  82     /// ```no_run
  83     /// use std::io;
  84     /// use std::fs::File;
  85     /// use std::os::unix::prelude::FileExt;
  86     ///
  87     /// fn main() -> io::Result<()> {
  88     ///     let mut buf = [0u8; 8];
  89     ///     let file = File::open("foo.txt")?;
  90     ///
  91     ///     // We now read exactly 8 bytes from the offset 10.
  92     ///     file.read_exact_at(&mut buf, 10)?;
  93     ///     println!("read {} bytes: {:?}", buf.len(), buf);
  94     ///     Ok(())
  95     /// }
  96     /// ```
  97     #[stable(feature = "rw_exact_all_at", since = "1.33.0")]
  98     fn read_exact_at(&self, mut buf: &mut [u8], mut offset: u64) -> io::Result<()> {
  99         while !buf.is_empty() {
 100             match self.read_at(buf, offset) {
 101                 Ok(0) => break,
 102                 Ok(n) => {
 103                     let tmp = buf;
 104                     buf = &mut tmp[n..];
 105                     offset += n as u64;
 106                 }
 107                 Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
 108                 Err(e) => return Err(e),
 109             }
 110         }
 111         if !buf.is_empty() {
 112             Err(io::Error::new(io::ErrorKind::UnexpectedEof, "failed to fill whole buffer"))
 113         } else {
 114             Ok(())
 115         }
 116     }
 117
 118     /// Writes a number of bytes starting from a given offset.
 119     ///
 120     /// Returns the number of bytes written.
 121     ///
 122     /// The offset is relative to the start of the file and thus independent
 123     /// from the current cursor.
 124     ///
 125     /// The current file cursor is not affected by this function.
 126     ///
 127     /// When writing beyond the end of the file, the file is appropriately
 128     /// extended and the intermediate bytes are initialized with the value 0.
 129     ///
 130     /// Note that similar to [`File::write`], it is not an error to return a
 131     /// short write.
 132     ///
 133     /// [`File::write`]: fs::File::write
 134     ///
 135     /// # Examples
 136     ///
 137     /// ```no_run
 138     /// use std::fs::File;
 139     /// use std::io;
 140     /// use std::os::unix::prelude::FileExt;
 141     ///
 142     /// fn main() -> io::Result<()> {
 143     ///     let file = File::open("foo.txt")?;
 144     ///
 145     ///     // We now write at the offset 10.
 146     ///     file.write_at(b"sushi", 10)?;
 147     ///     Ok(())
 148     /// }
 149     /// ```
 150     #[stable(feature = "file_offset", since = "1.15.0")]
 151     fn write_at(&self, buf: &[u8], offset: u64) -> io::Result<usize>;
 152
 153     /// Attempts to write an entire buffer starting from a given offset.
 154     ///
 155     /// The offset is relative to the start of the file and thus independent
 156     /// from the current cursor.
 157     ///
 158     /// The current file cursor is not affected by this function.
 159     ///
 160     /// This method will continuously call [`write_at`] until there is no more data
 161     /// to be written or an error of non-[`io::ErrorKind::Interrupted`] kind is
 162     /// returned. This method will not return until the entire buffer has been
 163     /// successfully written or such an error occurs. The first error that is
 164     /// not of [`io::ErrorKind::Interrupted`] kind generated from this method will be
 165     /// returned.
 166     ///
 167     /// # Errors
 168     ///
 169     /// This function will return the first error of
 170     /// non-[`io::ErrorKind::Interrupted`] kind that [`write_at`] returns.
 171     ///
 172     /// [`write_at`]: FileExt::write_at
 173     ///
 174     /// # Examples
 175     ///
 176     /// ```no_run
 177     /// use std::fs::File;
 178     /// use std::io;
 179     /// use std::os::unix::prelude::FileExt;
 180     ///
 181     /// fn main() -> io::Result<()> {
 182     ///     let file = File::open("foo.txt")?;
 183     ///
 184     ///     // We now write at the offset 10.
 185     ///     file.write_all_at(b"sushi", 10)?;
 186     ///     Ok(())
 187     /// }
 188     /// ```
 189     #[stable(feature = "rw_exact_all_at", since = "1.33.0")]
 190     fn write_all_at(&self, mut buf: &[u8], mut offset: u64) -> io::Result<()> {
 191         while !buf.is_empty() {
 192             match self.write_at(buf, offset) {
 193                 Ok(0) => {
 194                     return Err(io::Error::new(
 195                         io::ErrorKind::WriteZero,
 196                         "failed to write whole buffer",
 197                     ));
 198                 }
 199                 Ok(n) => {
 200                     buf = &buf[n..];
 201                     offset += n as u64
 202                 }
 203                 Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
 204                 Err(e) => return Err(e),
 205             }
 206         }
 207         Ok(())
 208     }
 209 }
 210
 211 #[stable(feature = "file_offset", since = "1.15.0")]
 212 impl FileExt for fs::File {
 213     fn read_at(&self, buf: &mut [u8], offset: u64) -> io::Result<usize> {
 214         self.as_inner().read_at(buf, offset)
 215     }
 216     fn write_at(&self, buf: &[u8], offset: u64) -> io::Result<usize> {
 217         self.as_inner().write_at(buf, offset)
 218     }
 219 }
 220
 221 /// Unix-specific extensions to [`fs::Permissions`].
 222 #[stable(feature = "fs_ext", since = "1.1.0")]
 223 pub trait PermissionsExt {
 224     /// Returns the underlying raw `st_mode` bits that contain the standard
 225     /// Unix permissions for this file.
 226     ///
 227     /// # Examples
 228     ///
 229     /// ```no_run
 230     /// use std::fs::File;
 231     /// use std::os::unix::fs::PermissionsExt;
 232     ///
 233     /// fn main() -> std::io::Result<()> {
 234     ///     let f = File::create("foo.txt")?;
 235     ///     let metadata = f.metadata()?;
 236     ///     let permissions = metadata.permissions();
 237     ///
 238     ///     println!("permissions: {:o}", permissions.mode());
 239     ///     Ok(())
 240     /// }
 241     /// ```
 242     #[stable(feature = "fs_ext", since = "1.1.0")]
 243     fn mode(&self) -> u32;
 244
 245     /// Sets the underlying raw bits for this set of permissions.
 246     ///
 247     /// # Examples
 248     ///
 249     /// ```no_run
 250     /// use std::fs::File;
 251     /// use std::os::unix::fs::PermissionsExt;
 252     ///
 253     /// fn main() -> std::io::Result<()> {
 254     ///     let f = File::create("foo.txt")?;
 255     ///     let metadata = f.metadata()?;
 256     ///     let mut permissions = metadata.permissions();
 257     ///
 258     ///     permissions.set_mode(0o644); // Read/write for owner and read for others.
 259     ///     assert_eq!(permissions.mode(), 0o644);
 260     ///     Ok(())
 261     /// }
 262     /// ```
 263     #[stable(feature = "fs_ext", since = "1.1.0")]
 264     fn set_mode(&mut self, mode: u32);
 265
 266     /// Creates a new instance of `Permissions` from the given set of Unix
 267     /// permission bits.
 268     ///
 269     /// # Examples
 270     ///
 271     /// ```
 272     /// use std::fs::Permissions;
 273     /// use std::os::unix::fs::PermissionsExt;
 274     ///
 275     /// // Read/write for owner and read for others.
 276     /// let permissions = Permissions::from_mode(0o644);
 277     /// assert_eq!(permissions.mode(), 0o644);
 278     /// ```
 279     #[stable(feature = "fs_ext", since = "1.1.0")]
 280     fn from_mode(mode: u32) -> Self;
 281 }
 282
 283 #[stable(feature = "fs_ext", since = "1.1.0")]
 284 impl PermissionsExt for Permissions {
 285     fn mode(&self) -> u32 {
 286         self.as_inner().mode()
 287     }
 288
 289     fn set_mode(&mut self, mode: u32) {
 290         *self = Permissions::from_inner(FromInner::from_inner(mode));
 291     }
 292
 293     fn from_mode(mode: u32) -> Permissions {
 294         Permissions::from_inner(FromInner::from_inner(mode))
 295     }
 296 }
 297
 298 /// Unix-specific extensions to [`fs::OpenOptions`].
 299 #[stable(feature = "fs_ext", since = "1.1.0")]
 300 pub trait OpenOptionsExt {
 301     /// Sets the mode bits that a new file will be created with.
 302     ///
 303     /// If a new file is created as part of an `OpenOptions::open` call then this
 304     /// specified `mode` will be used as the permission bits for the new file.
 305     /// If no `mode` is set, the default of `0o666` will be used.
 306     /// The operating system masks out bits with the system's `umask`, to produce
 307     /// the final permissions.
 308     ///
 309     /// # Examples
 310     ///
 311     /// ```no_run
 312     /// use std::fs::OpenOptions;
 313     /// use std::os::unix::fs::OpenOptionsExt;
 314     ///
 315     /// # fn main() {
 316     /// let mut options = OpenOptions::new();
 317     /// options.mode(0o644); // Give read/write for owner and read for others.
 318     /// let file = options.open("foo.txt");
 319     /// # }
 320     /// ```
 321     #[stable(feature = "fs_ext", since = "1.1.0")]
 322     fn mode(&mut self, mode: u32) -> &mut Self;
 323
 324     /// Pass custom flags to the `flags` argument of `open`.
 325     ///
 326     /// The bits that define the access mode are masked out with `O_ACCMODE`, to
 327     /// ensure they do not interfere with the access mode set by Rusts options.
 328     ///
 329     /// Custom flags can only set flags, not remove flags set by Rusts options.
 330     /// This options overwrites any previously set custom flags.
 331     ///
 332     /// # Examples
 333     ///
 334     /// ```no_run
 335     /// # #![feature(rustc_private)]
 336     /// extern crate libc;
 337     /// use std::fs::OpenOptions;
 338     /// use std::os::unix::fs::OpenOptionsExt;
 339     ///
 340     /// # fn main() {
 341     /// let mut options = OpenOptions::new();
 342     /// options.write(true);
 343     /// if cfg!(unix) {
 344     ///     options.custom_flags(libc::O_NOFOLLOW);
 345     /// }
 346     /// let file = options.open("foo.txt");
 347     /// # }
 348     /// ```
 349     #[stable(feature = "open_options_ext", since = "1.10.0")]
 350     fn custom_flags(&mut self, flags: i32) -> &mut Self;
 351 }
 352
 353 #[stable(feature = "fs_ext", since = "1.1.0")]
 354 impl OpenOptionsExt for OpenOptions {
 355     fn mode(&mut self, mode: u32) -> &mut OpenOptions {
 356         self.as_inner_mut().mode(mode);
 357         self
 358     }
 359
 360     fn custom_flags(&mut self, flags: i32) -> &mut OpenOptions {
 361         self.as_inner_mut().custom_flags(flags);
 362         self
 363     }
 364 }
 365
 366 /// Unix-specific extensions to [`fs::Metadata`].
 367 #[stable(feature = "metadata_ext", since = "1.1.0")]
 368 pub trait MetadataExt {
 369     /// Returns the ID of the device containing the file.
 370     ///
 371     /// # Examples
 372     ///
 373     /// ```no_run
 374     /// use std::io;
 375     /// use std::fs;
 376     /// use std::os::unix::fs::MetadataExt;
 377     ///
 378     /// fn main() -> io::Result<()> {
 379     ///     let meta = fs::metadata("some_file")?;
 380     ///     let dev_id = meta.dev();
 381     ///     Ok(())
 382     /// }
 383     /// ```
 384     #[stable(feature = "metadata_ext", since = "1.1.0")]
 385     fn dev(&self) -> u64;
 386     /// Returns the inode number.
 387     ///
 388     /// # Examples
 389     ///
 390     /// ```no_run
 391     /// use std::fs;
 392     /// use std::os::unix::fs::MetadataExt;
 393     /// use std::io;
 394     ///
 395     /// fn main() -> io::Result<()> {
 396     ///     let meta = fs::metadata("some_file")?;
 397     ///     let inode = meta.ino();
 398     ///     Ok(())
 399     /// }
 400     /// ```
 401     #[stable(feature = "metadata_ext", since = "1.1.0")]
 402     fn ino(&self) -> u64;
 403     /// Returns the rights applied to this file.
 404     ///
 405     /// # Examples
 406     ///
 407     /// ```no_run
 408     /// use std::fs;
 409     /// use std::os::unix::fs::MetadataExt;
 410     /// use std::io;
 411     ///
 412     /// fn main() -> io::Result<()> {
 413     ///     let meta = fs::metadata("some_file")?;
 414     ///     let mode = meta.mode();
 415     ///     let user_has_write_access      = mode & 0o200;
 416     ///     let user_has_read_write_access = mode & 0o600;
 417     ///     let group_has_read_access      = mode & 0o040;
 418     ///     let others_have_exec_access    = mode & 0o001;
 419     ///     Ok(())
 420     /// }
 421     /// ```
 422     #[stable(feature = "metadata_ext", since = "1.1.0")]
 423     fn mode(&self) -> u32;
 424     /// Returns the number of hard links pointing to this file.
 425     ///
 426     /// # Examples
 427     ///
 428     /// ```no_run
 429     /// use std::fs;
 430     /// use std::os::unix::fs::MetadataExt;
 431     /// use std::io;
 432     ///
 433     /// fn main() -> io::Result<()> {
 434     ///     let meta = fs::metadata("some_file")?;
 435     ///     let nb_hard_links = meta.nlink();
 436     ///     Ok(())
 437     /// }
 438     /// ```
 439     #[stable(feature = "metadata_ext", since = "1.1.0")]
 440     fn nlink(&self) -> u64;
 441     /// Returns the user ID of the owner of this file.
 442     ///
 443     /// # Examples
 444     ///
 445     /// ```no_run
 446     /// use std::fs;
 447     /// use std::os::unix::fs::MetadataExt;
 448     /// use std::io;
 449     ///
 450     /// fn main() -> io::Result<()> {
 451     ///     let meta = fs::metadata("some_file")?;
 452     ///     let user_id = meta.uid();
 453     ///     Ok(())
 454     /// }
 455     /// ```
 456     #[stable(feature = "metadata_ext", since = "1.1.0")]
 457     fn uid(&self) -> u32;
 458     /// Returns the group ID of the owner of this file.
 459     ///
 460     /// # Examples
 461     ///
 462     /// ```no_run
 463     /// use std::fs;
 464     /// use std::os::unix::fs::MetadataExt;
 465     /// use std::io;
 466     ///
 467     /// fn main() -> io::Result<()> {
 468     ///     let meta = fs::metadata("some_file")?;
 469     ///     let group_id = meta.gid();
 470     ///     Ok(())
 471     /// }
 472     /// ```
 473     #[stable(feature = "metadata_ext", since = "1.1.0")]
 474     fn gid(&self) -> u32;
 475     /// Returns the device ID of this file (if it is a special one).
 476     ///
 477     /// # Examples
 478     ///
 479     /// ```no_run
 480     /// use std::fs;
 481     /// use std::os::unix::fs::MetadataExt;
 482     /// use std::io;
 483     ///
 484     /// fn main() -> io::Result<()> {
 485     ///     let meta = fs::metadata("some_file")?;
 486     ///     let device_id = meta.rdev();
 487     ///     Ok(())
 488     /// }
 489     /// ```
 490     #[stable(feature = "metadata_ext", since = "1.1.0")]
 491     fn rdev(&self) -> u64;
 492     /// Returns the total size of this file in bytes.
 493     ///
 494     /// # Examples
 495     ///
 496     /// ```no_run
 497     /// use std::fs;
 498     /// use std::os::unix::fs::MetadataExt;
 499     /// use std::io;
 500     ///
 501     /// fn main() -> io::Result<()> {
 502     ///     let meta = fs::metadata("some_file")?;
 503     ///     let file_size = meta.size();
 504     ///     Ok(())
 505     /// }
 506     /// ```
 507     #[stable(feature = "metadata_ext", since = "1.1.0")]
 508     fn size(&self) -> u64;
 509     /// Returns the last access time of the file, in seconds since Unix Epoch.
 510     ///
 511     /// # Examples
 512     ///
 513     /// ```no_run
 514     /// use std::fs;
 515     /// use std::os::unix::fs::MetadataExt;
 516     /// use std::io;
 517     ///
 518     /// fn main() -> io::Result<()> {
 519     ///     let meta = fs::metadata("some_file")?;
 520     ///     let last_access_time = meta.atime();
 521     ///     Ok(())
 522     /// }
 523     /// ```
 524     #[stable(feature = "metadata_ext", since = "1.1.0")]
 525     fn atime(&self) -> i64;
 526     /// Returns the last access time of the file, in nanoseconds since [`atime`].
 527     ///
 528     /// [`atime`]: MetadataExt::atime
 529     ///
 530     /// # Examples
 531     ///
 532     /// ```no_run
 533     /// use std::fs;
 534     /// use std::os::unix::fs::MetadataExt;
 535     /// use std::io;
 536     ///
 537     /// fn main() -> io::Result<()> {
 538     ///     let meta = fs::metadata("some_file")?;
 539     ///     let nano_last_access_time = meta.atime_nsec();
 540     ///     Ok(())
 541     /// }
 542     /// ```
 543     #[stable(feature = "metadata_ext", since = "1.1.0")]
 544     fn atime_nsec(&self) -> i64;
 545     /// Returns the last modification time of the file, in seconds since Unix Epoch.
 546     ///
 547     /// # Examples
 548     ///
 549     /// ```no_run
 550     /// use std::fs;
 551     /// use std::os::unix::fs::MetadataExt;
 552     /// use std::io;
 553     ///
 554     /// fn main() -> io::Result<()> {
 555     ///     let meta = fs::metadata("some_file")?;
 556     ///     let last_modification_time = meta.mtime();
 557     ///     Ok(())
 558     /// }
 559     /// ```
 560     #[stable(feature = "metadata_ext", since = "1.1.0")]
 561     fn mtime(&self) -> i64;
 562     /// Returns the last modification time of the file, in nanoseconds since [`mtime`].
 563     ///
 564     /// [`mtime`]: MetadataExt::mtime
 565     ///
 566     /// # Examples
 567     ///
 568     /// ```no_run
 569     /// use std::fs;
 570     /// use std::os::unix::fs::MetadataExt;
 571     /// use std::io;
 572     ///
 573     /// fn main() -> io::Result<()> {
 574     ///     let meta = fs::metadata("some_file")?;
 575     ///     let nano_last_modification_time = meta.mtime_nsec();
 576     ///     Ok(())
 577     /// }
 578     /// ```
 579     #[stable(feature = "metadata_ext", since = "1.1.0")]
 580     fn mtime_nsec(&self) -> i64;
 581     /// Returns the last status change time of the file, in seconds since Unix Epoch.
 582     ///
 583     /// # Examples
 584     ///
 585     /// ```no_run
 586     /// use std::fs;
 587     /// use std::os::unix::fs::MetadataExt;
 588     /// use std::io;
 589     ///
 590     /// fn main() -> io::Result<()> {
 591     ///     let meta = fs::metadata("some_file")?;
 592     ///     let last_status_change_time = meta.ctime();
 593     ///     Ok(())
 594     /// }
 595     /// ```
 596     #[stable(feature = "metadata_ext", since = "1.1.0")]
 597     fn ctime(&self) -> i64;
 598     /// Returns the last status change time of the file, in nanoseconds since [`ctime`].
 599     ///
 600     /// [`ctime`]: MetadataExt::ctime
 601     ///
 602     /// # Examples
 603     ///
 604     /// ```no_run
 605     /// use std::fs;
 606     /// use std::os::unix::fs::MetadataExt;
 607     /// use std::io;
 608     ///
 609     /// fn main() -> io::Result<()> {
 610     ///     let meta = fs::metadata("some_file")?;
 611     ///     let nano_last_status_change_time = meta.ctime_nsec();
 612     ///     Ok(())
 613     /// }
 614     /// ```
 615     #[stable(feature = "metadata_ext", since = "1.1.0")]
 616     fn ctime_nsec(&self) -> i64;
 617     /// Returns the block size for filesystem I/O.
 618     ///
 619     /// # Examples
 620     ///
 621     /// ```no_run
 622     /// use std::fs;
 623     /// use std::os::unix::fs::MetadataExt;
 624     /// use std::io;
 625     ///
 626     /// fn main() -> io::Result<()> {
 627     ///     let meta = fs::metadata("some_file")?;
 628     ///     let block_size = meta.blksize();
 629     ///     Ok(())
 630     /// }
 631     /// ```
 632     #[stable(feature = "metadata_ext", since = "1.1.0")]
 633     fn blksize(&self) -> u64;
 634     /// Returns the number of blocks allocated to the file, in 512-byte units.
 635     ///
 636     /// Please note that this may be smaller than `st_size / 512` when the file has holes.
 637     ///
 638     /// # Examples
 639     ///
 640     /// ```no_run
 641     /// use std::fs;
 642     /// use std::os::unix::fs::MetadataExt;
 643     /// use std::io;
 644     ///
 645     /// fn main() -> io::Result<()> {
 646     ///     let meta = fs::metadata("some_file")?;
 647     ///     let blocks = meta.blocks();
 648     ///     Ok(())
 649     /// }
 650     /// ```
 651     #[stable(feature = "metadata_ext", since = "1.1.0")]
 652     fn blocks(&self) -> u64;
 653     #[cfg(target_os = "vxworks")]
 654     #[stable(feature = "metadata_ext", since = "1.1.0")]
 655     fn attrib(&self) -> u8;
 656 }
 657
 658 #[stable(feature = "metadata_ext", since = "1.1.0")]
 659 impl MetadataExt for fs::Metadata {
 660     fn dev(&self) -> u64 {
 661         self.st_dev()
 662     }
 663     fn ino(&self) -> u64 {
 664         self.st_ino()
 665     }
 666     fn mode(&self) -> u32 {
 667         self.st_mode()
 668     }
 669     fn nlink(&self) -> u64 {
 670         self.st_nlink()
 671     }
 672     fn uid(&self) -> u32 {
 673         self.st_uid()
 674     }
 675     fn gid(&self) -> u32 {
 676         self.st_gid()
 677     }
 678     fn rdev(&self) -> u64 {
 679         self.st_rdev()
 680     }
 681     fn size(&self) -> u64 {
 682         self.st_size()
 683     }
 684     fn atime(&self) -> i64 {
 685         self.st_atime()
 686     }
 687     fn atime_nsec(&self) -> i64 {
 688         self.st_atime_nsec()
 689     }
 690     fn mtime(&self) -> i64 {
 691         self.st_mtime()
 692     }
 693     fn mtime_nsec(&self) -> i64 {
 694         self.st_mtime_nsec()
 695     }
 696     fn ctime(&self) -> i64 {
 697         self.st_ctime()
 698     }
 699     fn ctime_nsec(&self) -> i64 {
 700         self.st_ctime_nsec()
 701     }
 702     fn blksize(&self) -> u64 {
 703         self.st_blksize()
 704     }
 705     fn blocks(&self) -> u64 {
 706         self.st_blocks()
 707     }
 708     #[cfg(target_os = "vxworks")]
 709     fn attrib(&self) -> u8 {
 710         self.st_attrib()
 711     }
 712 }
 713
 714 /// Unix-specific extensions for [`fs::FileType`].
 715 ///
 716 /// Adds support for special Unix file types such as block/character devices,
 717 /// pipes, and sockets.
 718 #[stable(feature = "file_type_ext", since = "1.5.0")]
 719 pub trait FileTypeExt {
 720     /// Returns `true` if this file type is a block device.
 721     ///
 722     /// # Examples
 723     ///
 724     /// ```no_run
 725     /// use std::fs;
 726     /// use std::os::unix::fs::FileTypeExt;
 727     /// use std::io;
 728     ///
 729     /// fn main() -> io::Result<()> {
 730     ///     let meta = fs::metadata("block_device_file")?;
 731     ///     let file_type = meta.file_type();
 732     ///     assert!(file_type.is_block_device());
 733     ///     Ok(())
 734     /// }
 735     /// ```
 736     #[stable(feature = "file_type_ext", since = "1.5.0")]
 737     fn is_block_device(&self) -> bool;
 738     /// Returns `true` if this file type is a char device.
 739     ///
 740     /// # Examples
 741     ///
 742     /// ```no_run
 743     /// use std::fs;
 744     /// use std::os::unix::fs::FileTypeExt;
 745     /// use std::io;
 746     ///
 747     /// fn main() -> io::Result<()> {
 748     ///     let meta = fs::metadata("char_device_file")?;
 749     ///     let file_type = meta.file_type();
 750     ///     assert!(file_type.is_char_device());
 751     ///     Ok(())
 752     /// }
 753     /// ```
 754     #[stable(feature = "file_type_ext", since = "1.5.0")]
 755     fn is_char_device(&self) -> bool;
 756     /// Returns `true` if this file type is a fifo.
 757     ///
 758     /// # Examples
 759     ///
 760     /// ```no_run
 761     /// use std::fs;
 762     /// use std::os::unix::fs::FileTypeExt;
 763     /// use std::io;
 764     ///
 765     /// fn main() -> io::Result<()> {
 766     ///     let meta = fs::metadata("fifo_file")?;
 767     ///     let file_type = meta.file_type();
 768     ///     assert!(file_type.is_fifo());
 769     ///     Ok(())
 770     /// }
 771     /// ```
 772     #[stable(feature = "file_type_ext", since = "1.5.0")]
 773     fn is_fifo(&self) -> bool;
 774     /// Returns `true` if this file type is a socket.
 775     ///
 776     /// # Examples
 777     ///
 778     /// ```no_run
 779     /// use std::fs;
 780     /// use std::os::unix::fs::FileTypeExt;
 781     /// use std::io;
 782     ///
 783     /// fn main() -> io::Result<()> {
 784     ///     let meta = fs::metadata("unix.socket")?;
 785     ///     let file_type = meta.file_type();
 786     ///     assert!(file_type.is_socket());
 787     ///     Ok(())
 788     /// }
 789     /// ```
 790     #[stable(feature = "file_type_ext", since = "1.5.0")]
 791     fn is_socket(&self) -> bool;
 792 }
 793
 794 #[stable(feature = "file_type_ext", since = "1.5.0")]
 795 impl FileTypeExt for fs::FileType {
 796     fn is_block_device(&self) -> bool {
 797         self.as_inner().is(libc::S_IFBLK)
 798     }
 799     fn is_char_device(&self) -> bool {
 800         self.as_inner().is(libc::S_IFCHR)
 801     }
 802     fn is_fifo(&self) -> bool {
 803         self.as_inner().is(libc::S_IFIFO)
 804     }
 805     fn is_socket(&self) -> bool {
 806         self.as_inner().is(libc::S_IFSOCK)
 807     }
 808 }
 809
 810 /// Unix-specific extension methods for [`fs::DirEntry`].
 811 #[stable(feature = "dir_entry_ext", since = "1.1.0")]
 812 pub trait DirEntryExt {
 813     /// Returns the underlying `d_ino` field in the contained `dirent`
 814     /// structure.
 815     ///
 816     /// # Examples
 817     ///
 818     /// ```
 819     /// use std::fs;
 820     /// use std::os::unix::fs::DirEntryExt;
 821     ///
 822     /// if let Ok(entries) = fs::read_dir(".") {
 823     ///     for entry in entries {
 824     ///         if let Ok(entry) = entry {
 825     ///             // Here, `entry` is a `DirEntry`.
 826     ///             println!("{:?}: {}", entry.file_name(), entry.ino());
 827     ///         }
 828     ///     }
 829     /// }
 830     /// ```
 831     #[stable(feature = "dir_entry_ext", since = "1.1.0")]
 832     fn ino(&self) -> u64;
 833 }
 834
 835 #[stable(feature = "dir_entry_ext", since = "1.1.0")]
 836 impl DirEntryExt for fs::DirEntry {
 837     fn ino(&self) -> u64 {
 838         self.as_inner().ino()
 839     }
 840 }
 841
 842 /// Creates a new symbolic link on the filesystem.
 843 ///
 844 /// The `dst` path will be a symbolic link pointing to the `src` path.
 845 ///
 846 /// # Examples
 847 ///
 848 /// ```no_run
 849 /// use std::os::unix::fs;
 850 ///
 851 /// fn main() -> std::io::Result<()> {
 852 ///     fs::symlink("a.txt", "b.txt")?;
 853 ///     Ok(())
 854 /// }
 855 /// ```
 856 #[stable(feature = "symlink", since = "1.1.0")]
 857 pub fn symlink<P: AsRef<Path>, Q: AsRef<Path>>(src: P, dst: Q) -> io::Result<()> {
 858     sys::fs::symlink(src.as_ref(), dst.as_ref())
 859 }
 860
 861 /// Unix-specific extensions to [`fs::DirBuilder`].
 862 #[stable(feature = "dir_builder", since = "1.6.0")]
 863 pub trait DirBuilderExt {
 864     /// Sets the mode to create new directories with. This option defaults to
 865     /// 0o777.
 866     ///
 867     /// # Examples
 868     ///
 869     /// ```no_run
 870     /// use std::fs::DirBuilder;
 871     /// use std::os::unix::fs::DirBuilderExt;
 872     ///
 873     /// let mut builder = DirBuilder::new();
 874     /// builder.mode(0o755);
 875     /// ```
 876     #[stable(feature = "dir_builder", since = "1.6.0")]
 877     fn mode(&mut self, mode: u32) -> &mut Self;
 878 }
 879
 880 #[stable(feature = "dir_builder", since = "1.6.0")]
 881 impl DirBuilderExt for fs::DirBuilder {
 882     fn mode(&mut self, mode: u32) -> &mut fs::DirBuilder {
 883         self.as_inner_mut().set_mode(mode);
 884         self
 885     }
 886 }