src/libstd/sys/unix/fs.rs

   1 // Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use os::unix::prelude::*;
  12
  13 use ffi::{CString, CStr, OsString, OsStr};
  14 use fmt;
  15 use io::{self, Error, ErrorKind, SeekFrom};
  16 use libc::{self, c_int, mode_t};
  17 use mem;
  18 use path::{Path, PathBuf};
  19 use ptr;
  20 use sync::Arc;
  21 use sys::fd::FileDesc;
  22 use sys::time::SystemTime;
  23 use sys::{cvt, cvt_r};
  24 use sys_common::{AsInner, FromInner};
  25
  26 #[cfg(any(target_os = "linux", target_os = "emscripten"))]
  27 use libc::{stat64, fstat64, lstat64, off64_t, ftruncate64, lseek64, dirent64, readdir64_r, open64};
  28 #[cfg(target_os = "android")]
  29 use libc::{stat as stat64, fstat as fstat64, lstat as lstat64, lseek64,
  30            dirent as dirent64, open as open64};
  31 #[cfg(not(any(target_os = "linux",
  32               target_os = "emscripten",
  33               target_os = "android")))]
  34 use libc::{stat as stat64, fstat as fstat64, lstat as lstat64, off_t as off64_t,
  35            ftruncate as ftruncate64, lseek as lseek64, dirent as dirent64, open as open64};
  36 #[cfg(not(any(target_os = "linux",
  37               target_os = "emscripten",
  38               target_os = "solaris")))]
  39 use libc::{readdir_r as readdir64_r};
  40
  41 pub struct File(FileDesc);
  42
  43 #[derive(Clone)]
  44 pub struct FileAttr {
  45     stat: stat64,
  46 }
  47
  48 pub struct ReadDir {
  49     dirp: Dir,
  50     root: Arc<PathBuf>,
  51 }
  52
  53 struct Dir(*mut libc::DIR);
  54
  55 unsafe impl Send for Dir {}
  56 unsafe impl Sync for Dir {}
  57
  58 pub struct DirEntry {
  59     entry: dirent64,
  60     root: Arc<PathBuf>,
  61     // We need to store an owned copy of the directory name
  62     // on Solaris because a) it uses a zero-length array to
  63     // store the name, b) its lifetime between readdir calls
  64     // is not guaranteed.
  65     #[cfg(target_os = "solaris")]
  66     name: Box<[u8]>
  67 }
  68
  69 #[derive(Clone, Debug)]
  70 pub struct OpenOptions {
  71     // generic
  72     read: bool,
  73     write: bool,
  74     append: bool,
  75     truncate: bool,
  76     create: bool,
  77     create_new: bool,
  78     // system-specific
  79     custom_flags: i32,
  80     mode: mode_t,
  81 }
  82
  83 #[derive(Clone, PartialEq, Eq, Debug)]
  84 pub struct FilePermissions { mode: mode_t }
  85
  86 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
  87 pub struct FileType { mode: mode_t }
  88
  89 #[derive(Debug)]
  90 pub struct DirBuilder { mode: mode_t }
  91
  92 impl FileAttr {
  93     pub fn size(&self) -> u64 { self.stat.st_size as u64 }
  94     pub fn perm(&self) -> FilePermissions {
  95         FilePermissions { mode: (self.stat.st_mode as mode_t) & 0o777 }
  96     }
  97
  98     pub fn file_type(&self) -> FileType {
  99         FileType { mode: self.stat.st_mode as mode_t }
 100     }
 101 }
 102
 103 #[cfg(target_os = "netbsd")]
 104 impl FileAttr {
 105     pub fn modified(&self) -> io::Result<SystemTime> {
 106         Ok(SystemTime::from(libc::timespec {
 107             tv_sec: self.stat.st_mtime as libc::time_t,
 108             tv_nsec: self.stat.st_mtimensec as libc::c_long,
 109         }))
 110     }
 111
 112     pub fn accessed(&self) -> io::Result<SystemTime> {
 113         Ok(SystemTime::from(libc::timespec {
 114             tv_sec: self.stat.st_atime as libc::time_t,
 115             tv_nsec: self.stat.st_atimensec as libc::c_long,
 116         }))
 117     }
 118
 119     pub fn created(&self) -> io::Result<SystemTime> {
 120         Ok(SystemTime::from(libc::timespec {
 121             tv_sec: self.stat.st_birthtime as libc::time_t,
 122             tv_nsec: self.stat.st_birthtimensec as libc::c_long,
 123         }))
 124     }
 125 }
 126
 127 #[cfg(not(target_os = "netbsd"))]
 128 impl FileAttr {
 129     pub fn modified(&self) -> io::Result<SystemTime> {
 130         Ok(SystemTime::from(libc::timespec {
 131             tv_sec: self.stat.st_mtime as libc::time_t,
 132             tv_nsec: self.stat.st_mtime_nsec as libc::c_long,
 133         }))
 134     }
 135
 136     pub fn accessed(&self) -> io::Result<SystemTime> {
 137         Ok(SystemTime::from(libc::timespec {
 138             tv_sec: self.stat.st_atime as libc::time_t,
 139             tv_nsec: self.stat.st_atime_nsec as libc::c_long,
 140         }))
 141     }
 142
 143     #[cfg(any(target_os = "bitrig",
 144               target_os = "freebsd",
 145               target_os = "openbsd",
 146               target_os = "macos",
 147               target_os = "ios"))]
 148     pub fn created(&self) -> io::Result<SystemTime> {
 149         Ok(SystemTime::from(libc::timespec {
 150             tv_sec: self.stat.st_birthtime as libc::time_t,
 151             tv_nsec: self.stat.st_birthtime_nsec as libc::c_long,
 152         }))
 153     }
 154
 155     #[cfg(not(any(target_os = "bitrig",
 156                   target_os = "freebsd",
 157                   target_os = "openbsd",
 158                   target_os = "macos",
 159                   target_os = "ios")))]
 160     pub fn created(&self) -> io::Result<SystemTime> {
 161         Err(io::Error::new(io::ErrorKind::Other,
 162                            "creation time is not available on this platform \
 163                             currently"))
 164     }
 165 }
 166
 167 impl AsInner<stat64> for FileAttr {
 168     fn as_inner(&self) -> &stat64 { &self.stat }
 169 }
 170
 171 impl FilePermissions {
 172     pub fn readonly(&self) -> bool { self.mode & 0o222 == 0 }
 173     pub fn set_readonly(&mut self, readonly: bool) {
 174         if readonly {
 175             self.mode &= !0o222;
 176         } else {
 177             self.mode |= 0o222;
 178         }
 179     }
 180     pub fn mode(&self) -> u32 { self.mode as u32 }
 181 }
 182
 183 impl FileType {
 184     pub fn is_dir(&self) -> bool { self.is(libc::S_IFDIR) }
 185     pub fn is_file(&self) -> bool { self.is(libc::S_IFREG) }
 186     pub fn is_symlink(&self) -> bool { self.is(libc::S_IFLNK) }
 187
 188     pub fn is(&self, mode: mode_t) -> bool { self.mode & libc::S_IFMT == mode }
 189 }
 190
 191 impl FromInner<u32> for FilePermissions {
 192     fn from_inner(mode: u32) -> FilePermissions {
 193         FilePermissions { mode: mode as mode_t }
 194     }
 195 }
 196
 197 impl fmt::Debug for ReadDir {
 198     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 199         // This will only be called from std::fs::ReadDir, which will add a "ReadDir()" frame.
 200         // Thus the result will be e g 'ReadDir("/home")'
 201         fmt::Debug::fmt(&*self.root, f)
 202     }
 203 }
 204
 205 impl Iterator for ReadDir {
 206     type Item = io::Result<DirEntry>;
 207
 208     #[cfg(target_os = "solaris")]
 209     fn next(&mut self) -> Option<io::Result<DirEntry>> {
 210         unsafe {
 211             loop {
 212                 // Although readdir_r(3) would be a correct function to use here because
 213                 // of the thread safety, on Illumos the readdir(3C) function is safe to use
 214                 // in threaded applications and it is generally preferred over the
 215                 // readdir_r(3C) function.
 216                 super::os::set_errno(0);
 217                 let entry_ptr = libc::readdir(self.dirp.0);
 218                 if entry_ptr.is_null() {
 219                     // NULL can mean either the end is reached or an error occurred.
 220                     // So we had to clear errno beforehand to check for an error now.
 221                     return match super::os::errno() {
 222                         0 => None,
 223                         e => Some(Err(Error::from_raw_os_error(e))),
 224                     }
 225                 }
 226
 227                 let name = (*entry_ptr).d_name.as_ptr();
 228                 let namelen = libc::strlen(name) as usize;
 229
 230                 let ret = DirEntry {
 231                     entry: *entry_ptr,
 232                     name: ::slice::from_raw_parts(name as *const u8,
 233                                                   namelen as usize).to_owned().into_boxed_slice(),
 234                     root: self.root.clone()
 235                 };
 236                 if ret.name_bytes() != b"." && ret.name_bytes() != b".." {
 237                     return Some(Ok(ret))
 238                 }
 239             }
 240         }
 241     }
 242
 243     #[cfg(not(target_os = "solaris"))]
 244     fn next(&mut self) -> Option<io::Result<DirEntry>> {
 245         unsafe {
 246             let mut ret = DirEntry {
 247                 entry: mem::zeroed(),
 248                 root: self.root.clone()
 249             };
 250             let mut entry_ptr = ptr::null_mut();
 251             loop {
 252                 if readdir64_r(self.dirp.0, &mut ret.entry, &mut entry_ptr) != 0 {
 253                     return Some(Err(Error::last_os_error()))
 254                 }
 255                 if entry_ptr.is_null() {
 256                     return None
 257                 }
 258                 if ret.name_bytes() != b"." && ret.name_bytes() != b".." {
 259                     return Some(Ok(ret))
 260                 }
 261             }
 262         }
 263     }
 264 }
 265
 266 impl Drop for Dir {
 267     fn drop(&mut self) {
 268         let r = unsafe { libc::closedir(self.0) };
 269         debug_assert_eq!(r, 0);
 270     }
 271 }
 272
 273 impl DirEntry {
 274     pub fn path(&self) -> PathBuf {
 275         self.root.join(OsStr::from_bytes(self.name_bytes()))
 276     }
 277
 278     pub fn file_name(&self) -> OsString {
 279         OsStr::from_bytes(self.name_bytes()).to_os_string()
 280     }
 281
 282     pub fn metadata(&self) -> io::Result<FileAttr> {
 283         lstat(&self.path())
 284     }
 285
 286     #[cfg(target_os = "solaris")]
 287     pub fn file_type(&self) -> io::Result<FileType> {
 288         stat(&self.path()).map(|m| m.file_type())
 289     }
 290
 291     #[cfg(target_os = "haiku")]
 292     pub fn file_type(&self) -> io::Result<FileType> {
 293         lstat(&self.path()).map(|m| m.file_type())
 294     }
 295
 296     #[cfg(not(any(target_os = "solaris", target_os = "haiku")))]
 297     pub fn file_type(&self) -> io::Result<FileType> {
 298         match self.entry.d_type {
 299             libc::DT_CHR => Ok(FileType { mode: libc::S_IFCHR }),
 300             libc::DT_FIFO => Ok(FileType { mode: libc::S_IFIFO }),
 301             libc::DT_LNK => Ok(FileType { mode: libc::S_IFLNK }),
 302             libc::DT_REG => Ok(FileType { mode: libc::S_IFREG }),
 303             libc::DT_SOCK => Ok(FileType { mode: libc::S_IFSOCK }),
 304             libc::DT_DIR => Ok(FileType { mode: libc::S_IFDIR }),
 305             libc::DT_BLK => Ok(FileType { mode: libc::S_IFBLK }),
 306             _ => lstat(&self.path()).map(|m| m.file_type()),
 307         }
 308     }
 309
 310     #[cfg(any(target_os = "macos",
 311               target_os = "ios",
 312               target_os = "linux",
 313               target_os = "emscripten",
 314               target_os = "android",
 315               target_os = "solaris",
 316               target_os = "haiku",
 317               target_os = "fuchsia"))]
 318     pub fn ino(&self) -> u64 {
 319         self.entry.d_ino as u64
 320     }
 321
 322     #[cfg(any(target_os = "freebsd",
 323               target_os = "openbsd",
 324               target_os = "bitrig",
 325               target_os = "netbsd",
 326               target_os = "dragonfly"))]
 327     pub fn ino(&self) -> u64 {
 328         self.entry.d_fileno as u64
 329     }
 330
 331     #[cfg(any(target_os = "macos",
 332               target_os = "ios",
 333               target_os = "netbsd",
 334               target_os = "openbsd",
 335               target_os = "freebsd",
 336               target_os = "dragonfly",
 337               target_os = "bitrig"))]
 338     fn name_bytes(&self) -> &[u8] {
 339         unsafe {
 340             ::slice::from_raw_parts(self.entry.d_name.as_ptr() as *const u8,
 341                                     self.entry.d_namlen as usize)
 342         }
 343     }
 344     #[cfg(any(target_os = "android",
 345               target_os = "linux",
 346               target_os = "emscripten",
 347               target_os = "haiku",
 348               target_os = "fuchsia"))]
 349     fn name_bytes(&self) -> &[u8] {
 350         unsafe {
 351             CStr::from_ptr(self.entry.d_name.as_ptr()).to_bytes()
 352         }
 353     }
 354     #[cfg(target_os = "solaris")]
 355     fn name_bytes(&self) -> &[u8] {
 356         &*self.name
 357     }
 358 }
 359
 360 impl OpenOptions {
 361     pub fn new() -> OpenOptions {
 362         OpenOptions {
 363             // generic
 364             read: false,
 365             write: false,
 366             append: false,
 367             truncate: false,
 368             create: false,
 369             create_new: false,
 370             // system-specific
 371             custom_flags: 0,
 372             mode: 0o666,
 373         }
 374     }
 375
 376     pub fn read(&mut self, read: bool) { self.read = read; }
 377     pub fn write(&mut self, write: bool) { self.write = write; }
 378     pub fn append(&mut self, append: bool) { self.append = append; }
 379     pub fn truncate(&mut self, truncate: bool) { self.truncate = truncate; }
 380     pub fn create(&mut self, create: bool) { self.create = create; }
 381     pub fn create_new(&mut self, create_new: bool) { self.create_new = create_new; }
 382
 383     pub fn custom_flags(&mut self, flags: i32) { self.custom_flags = flags; }
 384     pub fn mode(&mut self, mode: u32) { self.mode = mode as mode_t; }
 385
 386     fn get_access_mode(&self) -> io::Result<c_int> {
 387         match (self.read, self.write, self.append) {
 388             (true,  false, false) => Ok(libc::O_RDONLY),
 389             (false, true,  false) => Ok(libc::O_WRONLY),
 390             (true,  true,  false) => Ok(libc::O_RDWR),
 391             (false, _,     true)  => Ok(libc::O_WRONLY | libc::O_APPEND),
 392             (true,  _,     true)  => Ok(libc::O_RDWR | libc::O_APPEND),
 393             (false, false, false) => Err(Error::from_raw_os_error(libc::EINVAL)),
 394         }
 395     }
 396
 397     fn get_creation_mode(&self) -> io::Result<c_int> {
 398         match (self.write, self.append) {
 399             (true, false) => {}
 400             (false, false) =>
 401                 if self.truncate || self.create || self.create_new {
 402                     return Err(Error::from_raw_os_error(libc::EINVAL));
 403                 },
 404             (_, true) =>
 405                 if self.truncate && !self.create_new {
 406                     return Err(Error::from_raw_os_error(libc::EINVAL));
 407                 },
 408         }
 409
 410         Ok(match (self.create, self.truncate, self.create_new) {
 411                 (false, false, false) => 0,
 412                 (true,  false, false) => libc::O_CREAT,
 413                 (false, true,  false) => libc::O_TRUNC,
 414                 (true,  true,  false) => libc::O_CREAT | libc::O_TRUNC,
 415                 (_,      _,    true)  => libc::O_CREAT | libc::O_EXCL,
 416            })
 417     }
 418 }
 419
 420 impl File {
 421     pub fn open(path: &Path, opts: &OpenOptions) -> io::Result<File> {
 422         let path = cstr(path)?;
 423         File::open_c(&path, opts)
 424     }
 425
 426     pub fn open_c(path: &CStr, opts: &OpenOptions) -> io::Result<File> {
 427         let flags = libc::O_CLOEXEC |
 428                     opts.get_access_mode()? |
 429                     opts.get_creation_mode()? |
 430                     (opts.custom_flags as c_int & !libc::O_ACCMODE);
 431         let fd = cvt_r(|| unsafe {
 432             open64(path.as_ptr(), flags, opts.mode as c_int)
 433         })?;
 434         let fd = FileDesc::new(fd);
 435
 436         // Currently the standard library supports Linux 2.6.18 which did not
 437         // have the O_CLOEXEC flag (passed above). If we're running on an older
 438         // Linux kernel then the flag is just ignored by the OS, so we continue
 439         // to explicitly ask for a CLOEXEC fd here.
 440         //
 441         // The CLOEXEC flag, however, is supported on versions of OSX/BSD/etc
 442         // that we support, so we only do this on Linux currently.
 443         if cfg!(target_os = "linux") {
 444             fd.set_cloexec()?;
 445         }
 446
 447         Ok(File(fd))
 448     }
 449
 450     pub fn file_attr(&self) -> io::Result<FileAttr> {
 451         let mut stat: stat64 = unsafe { mem::zeroed() };
 452         cvt(unsafe {
 453             fstat64(self.0.raw(), &mut stat)
 454         })?;
 455         Ok(FileAttr { stat: stat })
 456     }
 457
 458     pub fn fsync(&self) -> io::Result<()> {
 459         cvt_r(|| unsafe { libc::fsync(self.0.raw()) })?;
 460         Ok(())
 461     }
 462
 463     pub fn datasync(&self) -> io::Result<()> {
 464         cvt_r(|| unsafe { os_datasync(self.0.raw()) })?;
 465         return Ok(());
 466
 467         #[cfg(any(target_os = "macos", target_os = "ios"))]
 468         unsafe fn os_datasync(fd: c_int) -> c_int {
 469             libc::fcntl(fd, libc::F_FULLFSYNC)
 470         }
 471         #[cfg(target_os = "linux")]
 472         unsafe fn os_datasync(fd: c_int) -> c_int { libc::fdatasync(fd) }
 473         #[cfg(not(any(target_os = "macos",
 474                       target_os = "ios",
 475                       target_os = "linux")))]
 476         unsafe fn os_datasync(fd: c_int) -> c_int { libc::fsync(fd) }
 477     }
 478
 479     pub fn truncate(&self, size: u64) -> io::Result<()> {
 480         #[cfg(target_os = "android")]
 481         return ::sys::android::ftruncate64(self.0.raw(), size);
 482
 483         #[cfg(not(target_os = "android"))]
 484         return cvt_r(|| unsafe {
 485             ftruncate64(self.0.raw(), size as off64_t)
 486         }).map(|_| ());
 487     }
 488
 489     pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> {
 490         self.0.read(buf)
 491     }
 492
 493     pub fn read_to_end(&self, buf: &mut Vec<u8>) -> io::Result<usize> {
 494         self.0.read_to_end(buf)
 495     }
 496
 497     pub fn read_at(&self, buf: &mut [u8], offset: u64) -> io::Result<usize> {
 498         self.0.read_at(buf, offset)
 499     }
 500
 501     pub fn write(&self, buf: &[u8]) -> io::Result<usize> {
 502         self.0.write(buf)
 503     }
 504
 505     pub fn write_at(&self, buf: &[u8], offset: u64) -> io::Result<usize> {
 506         self.0.write_at(buf, offset)
 507     }
 508
 509     pub fn flush(&self) -> io::Result<()> { Ok(()) }
 510
 511     pub fn seek(&self, pos: SeekFrom) -> io::Result<u64> {
 512         let (whence, pos) = match pos {
 513             // Casting to `i64` is fine, too large values will end up as
 514             // negative which will cause an error in `lseek64`.
 515             SeekFrom::Start(off) => (libc::SEEK_SET, off as i64),
 516             SeekFrom::End(off) => (libc::SEEK_END, off),
 517             SeekFrom::Current(off) => (libc::SEEK_CUR, off),
 518         };
 519         let n = cvt(unsafe { lseek64(self.0.raw(), pos, whence) })?;
 520         Ok(n as u64)
 521     }
 522
 523     pub fn duplicate(&self) -> io::Result<File> {
 524         self.0.duplicate().map(File)
 525     }
 526
 527     pub fn fd(&self) -> &FileDesc { &self.0 }
 528
 529     pub fn into_fd(self) -> FileDesc { self.0 }
 530
 531     pub fn set_permissions(&self, perm: FilePermissions) -> io::Result<()> {
 532         cvt_r(|| unsafe { libc::fchmod(self.0.raw(), perm.mode) })?;
 533         Ok(())
 534     }
 535 }
 536
 537 impl DirBuilder {
 538     pub fn new() -> DirBuilder {
 539         DirBuilder { mode: 0o777 }
 540     }
 541
 542     pub fn mkdir(&self, p: &Path) -> io::Result<()> {
 543         let p = cstr(p)?;
 544         cvt(unsafe { libc::mkdir(p.as_ptr(), self.mode) })?;
 545         Ok(())
 546     }
 547
 548     pub fn set_mode(&mut self, mode: u32) {
 549         self.mode = mode as mode_t;
 550     }
 551 }
 552
 553 fn cstr(path: &Path) -> io::Result<CString> {
 554     Ok(CString::new(path.as_os_str().as_bytes())?)
 555 }
 556
 557 impl FromInner<c_int> for File {
 558     fn from_inner(fd: c_int) -> File {
 559         File(FileDesc::new(fd))
 560     }
 561 }
 562
 563 impl fmt::Debug for File {
 564     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 565         #[cfg(target_os = "linux")]
 566         fn get_path(fd: c_int) -> Option<PathBuf> {
 567             let mut p = PathBuf::from("/proc/self/fd");
 568             p.push(&fd.to_string());
 569             readlink(&p).ok()
 570         }
 571
 572         #[cfg(target_os = "macos")]
 573         fn get_path(fd: c_int) -> Option<PathBuf> {
 574             // FIXME: The use of PATH_MAX is generally not encouraged, but it
 575             // is inevitable in this case because OS X defines `fcntl` with
 576             // `F_GETPATH` in terms of `MAXPATHLEN`, and there are no
 577             // alternatives. If a better method is invented, it should be used
 578             // instead.
 579             let mut buf = vec![0;libc::PATH_MAX as usize];
 580             let n = unsafe { libc::fcntl(fd, libc::F_GETPATH, buf.as_ptr()) };
 581             if n == -1 {
 582                 return None;
 583             }
 584             let l = buf.iter().position(|&c| c == 0).unwrap();
 585             buf.truncate(l as usize);
 586             buf.shrink_to_fit();
 587             Some(PathBuf::from(OsString::from_vec(buf)))
 588         }
 589
 590         #[cfg(not(any(target_os = "linux", target_os = "macos")))]
 591         fn get_path(_fd: c_int) -> Option<PathBuf> {
 592             // FIXME(#24570): implement this for other Unix platforms
 593             None
 594         }
 595
 596         #[cfg(any(target_os = "linux", target_os = "macos"))]
 597         fn get_mode(fd: c_int) -> Option<(bool, bool)> {
 598             let mode = unsafe { libc::fcntl(fd, libc::F_GETFL) };
 599             if mode == -1 {
 600                 return None;
 601             }
 602             match mode & libc::O_ACCMODE {
 603                 libc::O_RDONLY => Some((true, false)),
 604                 libc::O_RDWR => Some((true, true)),
 605                 libc::O_WRONLY => Some((false, true)),
 606                 _ => None
 607             }
 608         }
 609
 610         #[cfg(not(any(target_os = "linux", target_os = "macos")))]
 611         fn get_mode(_fd: c_int) -> Option<(bool, bool)> {
 612             // FIXME(#24570): implement this for other Unix platforms
 613             None
 614         }
 615
 616         let fd = self.0.raw();
 617         let mut b = f.debug_struct("File");
 618         b.field("fd", &fd);
 619         if let Some(path) = get_path(fd) {
 620             b.field("path", &path);
 621         }
 622         if let Some((read, write)) = get_mode(fd) {
 623             b.field("read", &read).field("write", &write);
 624         }
 625         b.finish()
 626     }
 627 }
 628
 629 pub fn readdir(p: &Path) -> io::Result<ReadDir> {
 630     let root = Arc::new(p.to_path_buf());
 631     let p = cstr(p)?;
 632     unsafe {
 633         let ptr = libc::opendir(p.as_ptr());
 634         if ptr.is_null() {
 635             Err(Error::last_os_error())
 636         } else {
 637             Ok(ReadDir { dirp: Dir(ptr), root: root })
 638         }
 639     }
 640 }
 641
 642 pub fn unlink(p: &Path) -> io::Result<()> {
 643     let p = cstr(p)?;
 644     cvt(unsafe { libc::unlink(p.as_ptr()) })?;
 645     Ok(())
 646 }
 647
 648 pub fn rename(old: &Path, new: &Path) -> io::Result<()> {
 649     let old = cstr(old)?;
 650     let new = cstr(new)?;
 651     cvt(unsafe { libc::rename(old.as_ptr(), new.as_ptr()) })?;
 652     Ok(())
 653 }
 654
 655 pub fn set_perm(p: &Path, perm: FilePermissions) -> io::Result<()> {
 656     let p = cstr(p)?;
 657     cvt_r(|| unsafe { libc::chmod(p.as_ptr(), perm.mode) })?;
 658     Ok(())
 659 }
 660
 661 pub fn rmdir(p: &Path) -> io::Result<()> {
 662     let p = cstr(p)?;
 663     cvt(unsafe { libc::rmdir(p.as_ptr()) })?;
 664     Ok(())
 665 }
 666
 667 pub fn remove_dir_all(path: &Path) -> io::Result<()> {
 668     let filetype = lstat(path)?.file_type();
 669     if filetype.is_symlink() {
 670         unlink(path)
 671     } else {
 672         remove_dir_all_recursive(path)
 673     }
 674 }
 675
 676 fn remove_dir_all_recursive(path: &Path) -> io::Result<()> {
 677     for child in readdir(path)? {
 678         let child = child?;
 679         if child.file_type()?.is_dir() {
 680             remove_dir_all_recursive(&child.path())?;
 681         } else {
 682             unlink(&child.path())?;
 683         }
 684     }
 685     rmdir(path)
 686 }
 687
 688 pub fn readlink(p: &Path) -> io::Result<PathBuf> {
 689     let c_path = cstr(p)?;
 690     let p = c_path.as_ptr();
 691
 692     let mut buf = Vec::with_capacity(256);
 693
 694     loop {
 695         let buf_read = cvt(unsafe {
 696             libc::readlink(p, buf.as_mut_ptr() as *mut _, buf.capacity())
 697         })? as usize;
 698
 699         unsafe { buf.set_len(buf_read); }
 700
 701         if buf_read != buf.capacity() {
 702             buf.shrink_to_fit();
 703
 704             return Ok(PathBuf::from(OsString::from_vec(buf)));
 705         }
 706
 707         // Trigger the internal buffer resizing logic of `Vec` by requiring
 708         // more space than the current capacity. The length is guaranteed to be
 709         // the same as the capacity due to the if statement above.
 710         buf.reserve(1);
 711     }
 712 }
 713
 714 pub fn symlink(src: &Path, dst: &Path) -> io::Result<()> {
 715     let src = cstr(src)?;
 716     let dst = cstr(dst)?;
 717     cvt(unsafe { libc::symlink(src.as_ptr(), dst.as_ptr()) })?;
 718     Ok(())
 719 }
 720
 721 pub fn link(src: &Path, dst: &Path) -> io::Result<()> {
 722     let src = cstr(src)?;
 723     let dst = cstr(dst)?;
 724     cvt(unsafe { libc::link(src.as_ptr(), dst.as_ptr()) })?;
 725     Ok(())
 726 }
 727
 728 pub fn stat(p: &Path) -> io::Result<FileAttr> {
 729     let p = cstr(p)?;
 730     let mut stat: stat64 = unsafe { mem::zeroed() };
 731     cvt(unsafe {
 732         stat64(p.as_ptr(), &mut stat as *mut _ as *mut _)
 733     })?;
 734     Ok(FileAttr { stat: stat })
 735 }
 736
 737 pub fn lstat(p: &Path) -> io::Result<FileAttr> {
 738     let p = cstr(p)?;
 739     let mut stat: stat64 = unsafe { mem::zeroed() };
 740     cvt(unsafe {
 741         lstat64(p.as_ptr(), &mut stat as *mut _ as *mut _)
 742     })?;
 743     Ok(FileAttr { stat: stat })
 744 }
 745
 746 pub fn canonicalize(p: &Path) -> io::Result<PathBuf> {
 747     let path = CString::new(p.as_os_str().as_bytes())?;
 748     let buf;
 749     unsafe {
 750         let r = libc::realpath(path.as_ptr(), ptr::null_mut());
 751         if r.is_null() {
 752             return Err(io::Error::last_os_error())
 753         }
 754         buf = CStr::from_ptr(r).to_bytes().to_vec();
 755         libc::free(r as *mut _);
 756     }
 757     Ok(PathBuf::from(OsString::from_vec(buf)))
 758 }
 759
 760 pub fn copy(from: &Path, to: &Path) -> io::Result<u64> {
 761     use fs::{File, set_permissions};
 762     if !from.is_file() {
 763         return Err(Error::new(ErrorKind::InvalidInput,
 764                               "the source path is not an existing regular file"))
 765     }
 766
 767     let mut reader = File::open(from)?;
 768     let mut writer = File::create(to)?;
 769     let perm = reader.metadata()?.permissions();
 770
 771     let ret = io::copy(&mut reader, &mut writer)?;
 772     set_permissions(to, perm)?;
 773     Ok(ret)
 774 }