src/librustdoc/flock.rs

   1 // Copyright 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 //! Simple file-locking apis for each OS.
  12 //!
  13 //! This is not meant to be in the standard library, it does nothing with
  14 //! green/native threading. This is just a bare-bones enough solution for
  15 //! librustdoc, it is not production quality at all.
  16
  17 #![allow(non_camel_case_types)]
  18
  19 pub use self::imp::Lock;
  20
  21
  22 #[cfg(unix)]
  23 mod imp {
  24     use libc;
  25
  26     #[cfg(target_os = "linux")]
  27     mod os {
  28         use libc;
  29
  30         pub struct flock {
  31             pub l_type: libc::c_short,
  32             pub l_whence: libc::c_short,
  33             pub l_start: libc::off_t,
  34             pub l_len: libc::off_t,
  35             pub l_pid: libc::pid_t,
  36
  37             // not actually here, but brings in line with freebsd
  38             pub l_sysid: libc::c_int,
  39         }
  40
  41         pub static F_WRLCK: libc::c_short = 1;
  42         pub static F_UNLCK: libc::c_short = 2;
  43         pub static F_SETLK: libc::c_int = 6;
  44         pub static F_SETLKW: libc::c_int = 7;
  45     }
  46
  47     #[cfg(target_os = "freebsd")]
  48     mod os {
  49         use libc;
  50
  51         pub struct flock {
  52             pub l_start: libc::off_t,
  53             pub l_len: libc::off_t,
  54             pub l_pid: libc::pid_t,
  55             pub l_type: libc::c_short,
  56             pub l_whence: libc::c_short,
  57             pub l_sysid: libc::c_int,
  58         }
  59
  60         pub static F_UNLCK: libc::c_short = 2;
  61         pub static F_WRLCK: libc::c_short = 3;
  62         pub static F_SETLK: libc::c_int = 12;
  63         pub static F_SETLKW: libc::c_int = 13;
  64     }
  65
  66     #[cfg(target_os = "macos")]
  67     mod os {
  68         use libc;
  69
  70         pub struct flock {
  71             pub l_start: libc::off_t,
  72             pub l_len: libc::off_t,
  73             pub l_pid: libc::pid_t,
  74             pub l_type: libc::c_short,
  75             pub l_whence: libc::c_short,
  76
  77             // not actually here, but brings in line with freebsd
  78             pub l_sysid: libc::c_int,
  79         }
  80
  81         pub static F_UNLCK: libc::c_short = 2;
  82         pub static F_WRLCK: libc::c_short = 3;
  83         pub static F_SETLK: libc::c_int = 8;
  84         pub static F_SETLKW: libc::c_int = 9;
  85     }
  86
  87     pub struct Lock {
  88         fd: libc::c_int,
  89     }
  90
  91     impl Lock {
  92         pub fn new(p: &Path) -> Lock {
  93             let fd = p.with_c_str(|s| unsafe {
  94                 libc::open(s, libc::O_RDWR | libc::O_CREAT, libc::S_IRWXU)
  95             });
  96             assert!(fd > 0);
  97             let flock = os::flock {
  98                 l_start: 0,
  99                 l_len: 0,
 100                 l_pid: 0,
 101                 l_whence: libc::SEEK_SET as libc::c_short,
 102                 l_type: os::F_WRLCK,
 103                 l_sysid: 0,
 104             };
 105             let ret = unsafe {
 106                 libc::fcntl(fd, os::F_SETLKW, &flock as *os::flock)
 107             };
 108             if ret == -1 {
 109                 unsafe { libc::close(fd); }
 110                 fail!("could not lock `{}`", p.display())
 111             }
 112             Lock { fd: fd }
 113         }
 114     }
 115
 116     impl Drop for Lock {
 117         fn drop(&mut self) {
 118             let flock = os::flock {
 119                 l_start: 0,
 120                 l_len: 0,
 121                 l_pid: 0,
 122                 l_whence: libc::SEEK_SET as libc::c_short,
 123                 l_type: os::F_UNLCK,
 124                 l_sysid: 0,
 125             };
 126             unsafe {
 127                 libc::fcntl(self.fd, os::F_SETLK, &flock as *os::flock);
 128                 libc::close(self.fd);
 129             }
 130         }
 131     }
 132 }
 133
 134 #[cfg(windows)]
 135 mod imp {
 136     use libc;
 137     use std::mem;
 138     use std::os::win32::as_utf16_p;
 139     use std::os;
 140     use std::ptr;
 141
 142     static LOCKFILE_EXCLUSIVE_LOCK: libc::DWORD = 0x00000002;
 143
 144     extern "system" {
 145         fn LockFileEx(hFile: libc::HANDLE,
 146                       dwFlags: libc::DWORD,
 147                       dwReserved: libc::DWORD,
 148                       nNumberOfBytesToLockLow: libc::DWORD,
 149                       nNumberOfBytesToLockHigh: libc::DWORD,
 150                       lpOverlapped: libc::LPOVERLAPPED) -> libc::BOOL;
 151         fn UnlockFileEx(hFile: libc::HANDLE,
 152                         dwReserved: libc::DWORD,
 153                         nNumberOfBytesToLockLow: libc::DWORD,
 154                         nNumberOfBytesToLockHigh: libc::DWORD,
 155                         lpOverlapped: libc::LPOVERLAPPED) -> libc::BOOL;
 156     }
 157
 158     pub struct Lock {
 159         handle: libc::HANDLE,
 160     }
 161
 162     impl Lock {
 163         pub fn new(p: &Path) -> Lock {
 164             let handle = as_utf16_p(p.as_str().unwrap(), |p| unsafe {
 165                 libc::CreateFileW(p,
 166                                   libc::FILE_GENERIC_READ |
 167                                     libc::FILE_GENERIC_WRITE,
 168                                   libc::FILE_SHARE_READ |
 169                                     libc::FILE_SHARE_DELETE |
 170                                     libc::FILE_SHARE_WRITE,
 171                                   ptr::mut_null(),
 172                                   libc::CREATE_ALWAYS,
 173                                   libc::FILE_ATTRIBUTE_NORMAL,
 174                                   ptr::mut_null())
 175             });
 176             if handle as uint == libc::INVALID_HANDLE_VALUE as uint {
 177                 fail!("create file error: {}", os::last_os_error());
 178             }
 179             let mut overlapped: libc::OVERLAPPED = unsafe { mem::init() };
 180             let ret = unsafe {
 181                 LockFileEx(handle, LOCKFILE_EXCLUSIVE_LOCK, 0, 100, 0,
 182                            &mut overlapped)
 183             };
 184             if ret == 0 {
 185                 unsafe { libc::CloseHandle(handle); }
 186                 fail!("could not lock `{}`: {}", p.display(),
 187                       os::last_os_error())
 188             }
 189             Lock { handle: handle }
 190         }
 191     }
 192
 193     impl Drop for Lock {
 194         fn drop(&mut self) {
 195             let mut overlapped: libc::OVERLAPPED = unsafe { mem::init() };
 196             unsafe {
 197                 UnlockFileEx(self.handle, 0, 100, 0, &mut overlapped);
 198                 libc::CloseHandle(self.handle);
 199             }
 200         }
 201     }
 202 }