libgo/go/os/file_posix.go

   1 // Copyright 2009 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 // +build darwin freebsd linux netbsd openbsd windows
   6
   7 package os
   8
   9 import (
  10         "syscall"
  11         "time"
  12 )
  13
  14 func sigpipe() // implemented in package runtime
  15
  16 func epipecheck(file *File, e error) {
  17         if e == syscall.EPIPE {
  18                 file.nepipe++
  19                 if file.nepipe >= 10 {
  20                         sigpipe()
  21                 }
  22         } else {
  23                 file.nepipe = 0
  24         }
  25 }
  26
  27 // Link creates newname as a hard link to the oldname file.
  28 // If there is an error, it will be of type *LinkError.
  29 func Link(oldname, newname string) error {
  30         e := syscall.Link(oldname, newname)
  31         if e != nil {
  32                 return &LinkError{"link", oldname, newname, e}
  33         }
  34         return nil
  35 }
  36
  37 // Symlink creates newname as a symbolic link to oldname.
  38 // If there is an error, it will be of type *LinkError.
  39 func Symlink(oldname, newname string) error {
  40         e := syscall.Symlink(oldname, newname)
  41         if e != nil {
  42                 return &LinkError{"symlink", oldname, newname, e}
  43         }
  44         return nil
  45 }
  46
  47 // Readlink returns the destination of the named symbolic link.
  48 // If there is an error, it will be of type *PathError.
  49 func Readlink(name string) (string, error) {
  50         for len := 128; ; len *= 2 {
  51                 b := make([]byte, len)
  52                 n, e := syscall.Readlink(name, b)
  53                 if e != nil {
  54                         return "", &PathError{"readlink", name, e}
  55                 }
  56                 if n < len {
  57                         return string(b[0:n]), nil
  58                 }
  59         }
  60         // Silence 6g.
  61         return "", nil
  62 }
  63
  64 // Rename renames a file.
  65 func Rename(oldname, newname string) error {
  66         e := syscall.Rename(oldname, newname)
  67         if e != nil {
  68                 return &LinkError{"rename", oldname, newname, e}
  69         }
  70         return nil
  71 }
  72
  73 // syscallMode returns the syscall-specific mode bits from Go's portable mode bits.
  74 func syscallMode(i FileMode) (o uint32) {
  75         o |= uint32(i.Perm())
  76         if i&ModeSetuid != 0 {
  77                 o |= syscall.S_ISUID
  78         }
  79         if i&ModeSetgid != 0 {
  80                 o |= syscall.S_ISGID
  81         }
  82         if i&ModeSticky != 0 {
  83                 o |= syscall.S_ISVTX
  84         }
  85         // No mapping for Go's ModeTemporary (plan9 only).
  86         return
  87 }
  88
  89 // Chmod changes the mode of the named file to mode.
  90 // If the file is a symbolic link, it changes the mode of the link's target.
  91 // If there is an error, it will be of type *PathError.
  92 func Chmod(name string, mode FileMode) error {
  93         if e := syscall.Chmod(name, syscallMode(mode)); e != nil {
  94                 return &PathError{"chmod", name, e}
  95         }
  96         return nil
  97 }
  98
  99 // Chmod changes the mode of the file to mode.
 100 // If there is an error, it will be of type *PathError.
 101 func (f *File) Chmod(mode FileMode) error {
 102         if e := syscall.Fchmod(f.fd, syscallMode(mode)); e != nil {
 103                 return &PathError{"chmod", f.name, e}
 104         }
 105         return nil
 106 }
 107
 108 // Chown changes the numeric uid and gid of the named file.
 109 // If the file is a symbolic link, it changes the uid and gid of the link's target.
 110 // If there is an error, it will be of type *PathError.
 111 func Chown(name string, uid, gid int) error {
 112         if e := syscall.Chown(name, uid, gid); e != nil {
 113                 return &PathError{"chown", name, e}
 114         }
 115         return nil
 116 }
 117
 118 // Lchown changes the numeric uid and gid of the named file.
 119 // If the file is a symbolic link, it changes the uid and gid of the link itself.
 120 // If there is an error, it will be of type *PathError.
 121 func Lchown(name string, uid, gid int) error {
 122         if e := syscall.Lchown(name, uid, gid); e != nil {
 123                 return &PathError{"lchown", name, e}
 124         }
 125         return nil
 126 }
 127
 128 // Chown changes the numeric uid and gid of the named file.
 129 // If there is an error, it will be of type *PathError.
 130 func (f *File) Chown(uid, gid int) error {
 131         if e := syscall.Fchown(f.fd, uid, gid); e != nil {
 132                 return &PathError{"chown", f.name, e}
 133         }
 134         return nil
 135 }
 136
 137 // Truncate changes the size of the file.
 138 // It does not change the I/O offset.
 139 // If there is an error, it will be of type *PathError.
 140 func (f *File) Truncate(size int64) error {
 141         if e := syscall.Ftruncate(f.fd, size); e != nil {
 142                 return &PathError{"truncate", f.name, e}
 143         }
 144         return nil
 145 }
 146
 147 // Sync commits the current contents of the file to stable storage.
 148 // Typically, this means flushing the file system's in-memory copy
 149 // of recently written data to disk.
 150 func (f *File) Sync() (err error) {
 151         if f == nil {
 152                 return syscall.EINVAL
 153         }
 154         if e := syscall.Fsync(f.fd); e != nil {
 155                 return NewSyscallError("fsync", e)
 156         }
 157         return nil
 158 }
 159
 160 // Chtimes changes the access and modification times of the named
 161 // file, similar to the Unix utime() or utimes() functions.
 162 //
 163 // The underlying filesystem may truncate or round the values to a
 164 // less precise time unit.
 165 // If there is an error, it will be of type *PathError.
 166 func Chtimes(name string, atime time.Time, mtime time.Time) error {
 167         var utimes [2]syscall.Timeval
 168         atime_ns := atime.Unix()*1e9 + int64(atime.Nanosecond())
 169         mtime_ns := mtime.Unix()*1e9 + int64(mtime.Nanosecond())
 170         utimes[0] = syscall.NsecToTimeval(atime_ns)
 171         utimes[1] = syscall.NsecToTimeval(mtime_ns)
 172         if e := syscall.Utimes(name, utimes[0:]); e != nil {
 173                 return &PathError{"chtimes", name, e}
 174         }
 175         return nil
 176 }