github.com/philippgille/go@v0.0.0-20180418191957-236c567ba9b7/src/os/file_posix.go (about) 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 dragonfly freebsd linux nacl netbsd openbsd solaris windows 6 7 package os 8 9 import ( 10 "syscall" 11 "time" 12 ) 13 14 func sigpipe() // implemented in package runtime 15 16 // Readlink returns the destination of the named symbolic link. 17 // If there is an error, it will be of type *PathError. 18 func Readlink(name string) (string, error) { 19 for len := 128; ; len *= 2 { 20 b := make([]byte, len) 21 n, e := fixCount(syscall.Readlink(fixLongPath(name), b)) 22 if e != nil { 23 return "", &PathError{"readlink", name, e} 24 } 25 if n < len { 26 return string(b[0:n]), nil 27 } 28 } 29 } 30 31 // syscallMode returns the syscall-specific mode bits from Go's portable mode bits. 32 func syscallMode(i FileMode) (o uint32) { 33 o |= uint32(i.Perm()) 34 if i&ModeSetuid != 0 { 35 o |= syscall.S_ISUID 36 } 37 if i&ModeSetgid != 0 { 38 o |= syscall.S_ISGID 39 } 40 if i&ModeSticky != 0 { 41 o |= syscall.S_ISVTX 42 } 43 // No mapping for Go's ModeTemporary (plan9 only). 44 return 45 } 46 47 // See docs in file.go:Chmod. 48 func chmod(name string, mode FileMode) error { 49 if e := syscall.Chmod(fixLongPath(name), syscallMode(mode)); e != nil { 50 return &PathError{"chmod", name, e} 51 } 52 return nil 53 } 54 55 // See docs in file.go:(*File).Chmod. 56 func (f *File) chmod(mode FileMode) error { 57 if err := f.checkValid("chmod"); err != nil { 58 return err 59 } 60 if e := f.pfd.Fchmod(syscallMode(mode)); e != nil { 61 return f.wrapErr("chmod", e) 62 } 63 return nil 64 } 65 66 // Chown changes the numeric uid and gid of the named file. 67 // If the file is a symbolic link, it changes the uid and gid of the link's target. 68 // A uid or gid of -1 means to not change that value. 69 // If there is an error, it will be of type *PathError. 70 // 71 // On Windows or Plan 9, Chown always returns the syscall.EWINDOWS or 72 // EPLAN9 error, wrapped in *PathError. 73 func Chown(name string, uid, gid int) error { 74 if e := syscall.Chown(name, uid, gid); e != nil { 75 return &PathError{"chown", name, e} 76 } 77 return nil 78 } 79 80 // Lchown changes the numeric uid and gid of the named file. 81 // If the file is a symbolic link, it changes the uid and gid of the link itself. 82 // If there is an error, it will be of type *PathError. 83 // 84 // On Windows, it always returns the syscall.EWINDOWS error, wrapped 85 // in *PathError. 86 func Lchown(name string, uid, gid int) error { 87 if e := syscall.Lchown(name, uid, gid); e != nil { 88 return &PathError{"lchown", name, e} 89 } 90 return nil 91 } 92 93 // Chown changes the numeric uid and gid of the named file. 94 // If there is an error, it will be of type *PathError. 95 // 96 // On Windows, it always returns the syscall.EWINDOWS error, wrapped 97 // in *PathError. 98 func (f *File) Chown(uid, gid int) error { 99 if err := f.checkValid("chown"); err != nil { 100 return err 101 } 102 if e := f.pfd.Fchown(uid, gid); e != nil { 103 return f.wrapErr("chown", e) 104 } 105 return nil 106 } 107 108 // Truncate changes the size of the file. 109 // It does not change the I/O offset. 110 // If there is an error, it will be of type *PathError. 111 func (f *File) Truncate(size int64) error { 112 if err := f.checkValid("truncate"); err != nil { 113 return err 114 } 115 if e := f.pfd.Ftruncate(size); e != nil { 116 return f.wrapErr("truncate", e) 117 } 118 return nil 119 } 120 121 // Sync commits the current contents of the file to stable storage. 122 // Typically, this means flushing the file system's in-memory copy 123 // of recently written data to disk. 124 func (f *File) Sync() error { 125 if err := f.checkValid("sync"); err != nil { 126 return err 127 } 128 if e := f.pfd.Fsync(); e != nil { 129 return f.wrapErr("sync", e) 130 } 131 return nil 132 } 133 134 // Chtimes changes the access and modification times of the named 135 // file, similar to the Unix utime() or utimes() functions. 136 // 137 // The underlying filesystem may truncate or round the values to a 138 // less precise time unit. 139 // If there is an error, it will be of type *PathError. 140 func Chtimes(name string, atime time.Time, mtime time.Time) error { 141 var utimes [2]syscall.Timespec 142 utimes[0] = syscall.NsecToTimespec(atime.UnixNano()) 143 utimes[1] = syscall.NsecToTimespec(mtime.UnixNano()) 144 if e := syscall.UtimesNano(fixLongPath(name), utimes[0:]); e != nil { 145 return &PathError{"chtimes", name, e} 146 } 147 return nil 148 } 149 150 // Chdir changes the current working directory to the file, 151 // which must be a directory. 152 // If there is an error, it will be of type *PathError. 153 func (f *File) Chdir() error { 154 if err := f.checkValid("chdir"); err != nil { 155 return err 156 } 157 if e := f.pfd.Fchdir(); e != nil { 158 return f.wrapErr("chdir", e) 159 } 160 return nil 161 } 162 163 // setDeadline sets the read and write deadline. 164 func (f *File) setDeadline(t time.Time) error { 165 if err := f.checkValid("SetDeadline"); err != nil { 166 return err 167 } 168 return f.pfd.SetDeadline(t) 169 } 170 171 // setReadDeadline sets the read deadline. 172 func (f *File) setReadDeadline(t time.Time) error { 173 if err := f.checkValid("SetReadDeadline"); err != nil { 174 return err 175 } 176 return f.pfd.SetReadDeadline(t) 177 } 178 179 // setWriteDeadline sets the write deadline. 180 func (f *File) setWriteDeadline(t time.Time) error { 181 if err := f.checkValid("SetWriteDeadline"); err != nil { 182 return err 183 } 184 return f.pfd.SetWriteDeadline(t) 185 } 186 187 // checkValid checks whether f is valid for use. 188 // If not, it returns an appropriate error, perhaps incorporating the operation name op. 189 func (f *File) checkValid(op string) error { 190 if f == nil { 191 return ErrInvalid 192 } 193 return nil 194 }