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