// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
-// The os package provides a platform-independent interface to operating
-// system functionality. The design is Unix-like.
+// Package os provides a platform-independent interface to operating system
+// functionality. The design is Unix-like.
+// The os interface is intended to be uniform across all operating systems.
+// Features not generally available appear in the system-specific package syscall.
package os
import (
- "runtime"
"syscall"
)
-// File represents an open file descriptor.
-type File struct {
- fd int
- name string
- dirinfo *dirInfo // nil unless directory being read
- nepipe int // number of consecutive EPIPE in Write
-}
-
-// Fd returns the integer Unix file descriptor referencing the open file.
-func (file *File) Fd() int { return file.fd }
-
// Name returns the name of the file as presented to Open.
func (file *File) Name() string { return file.name }
-// NewFile returns a new File with the given file descriptor and name.
-func NewFile(fd int, name string) *File {
- if fd < 0 {
- return nil
- }
- f := &File{fd, name, nil, 0}
- runtime.SetFinalizer(f, (*File).Close)
- return f
-}
-
// Stdin, Stdout, and Stderr are open Files pointing to the standard input,
// standard output, and standard error file descriptors.
var (
O_RDWR int = syscall.O_RDWR // open the file read-write.
O_APPEND int = syscall.O_APPEND // append data to the file when writing.
O_ASYNC int = syscall.O_ASYNC // generate a signal when I/O is available.
- O_CREAT int = syscall.O_CREAT // create a new file if none exists.
- O_EXCL int = syscall.O_EXCL // used with O_CREAT, file must not exist
+ O_CREATE int = syscall.O_CREAT // create a new file if none exists.
+ O_EXCL int = syscall.O_EXCL // used with O_CREATE, file must not exist
O_NOCTTY int = syscall.O_NOCTTY // do not make file the controlling tty.
O_NONBLOCK int = syscall.O_NONBLOCK // open in non-blocking mode.
O_NDELAY int = O_NONBLOCK // synonym for O_NONBLOCK
O_SYNC int = syscall.O_SYNC // open for synchronous I/O.
O_TRUNC int = syscall.O_TRUNC // if possible, truncate file when opened.
- O_CREATE int = O_CREAT // create a new file if none exists.
+)
+
+// Seek whence values.
+const (
+ SEEK_SET int = 0 // seek relative to the origin of the file
+ SEEK_CUR int = 1 // seek relative to the current offset
+ SEEK_END int = 2 // seek relative to the end
)
type eofError int
if file == nil {
return 0, EINVAL
}
- n, e := syscall.Read(file.fd, b)
+ n, e := file.read(b)
if n < 0 {
n = 0
}
- if n == 0 && e == 0 {
+ if n == 0 && !iserror(e) {
return 0, EOF
}
- if e != 0 {
+ if iserror(e) {
err = &PathError{"read", file.name, Errno(e)}
}
return n, err
return 0, EINVAL
}
for len(b) > 0 {
- m, e := syscall.Pread(file.fd, b, off)
- if m == 0 && e == 0 {
+ m, e := file.pread(b, off)
+ if m == 0 && !iserror(e) {
return n, EOF
}
- if e != 0 {
+ if iserror(e) {
err = &PathError{"read", file.name, Errno(e)}
break
}
if file == nil {
return 0, EINVAL
}
- n, e := syscall.Write(file.fd, b)
+ n, e := file.write(b)
if n < 0 {
n = 0
}
- if e == syscall.EPIPE {
- file.nepipe++
- if file.nepipe >= 10 {
- Exit(syscall.EPIPE)
- }
- } else {
- file.nepipe = 0
- }
- if e != 0 {
+
+ epipecheck(file, e)
+
+ if iserror(e) {
err = &PathError{"write", file.name, Errno(e)}
}
return n, err
return 0, EINVAL
}
for len(b) > 0 {
- m, e := syscall.Pwrite(file.fd, b, off)
- if e != 0 {
+ m, e := file.pwrite(b, off)
+ if iserror(e) {
err = &PathError{"write", file.name, Errno(e)}
break
}
// relative to the current offset, and 2 means relative to the end.
// It returns the new offset and an Error, if any.
func (file *File) Seek(offset int64, whence int) (ret int64, err Error) {
- r, e := syscall.Seek(file.fd, offset, whence)
- if e == 0 && file.dirinfo != nil && r != 0 {
+ r, e := file.seek(offset, whence)
+ if !iserror(e) && file.dirinfo != nil && r != 0 {
e = syscall.EISDIR
}
- if e != 0 {
+ if iserror(e) {
return 0, &PathError{"seek", file.name, Errno(e)}
}
return r, nil
if file == nil {
return 0, EINVAL
}
- b := syscall.StringByteSlice(s)
- b = b[0 : len(b)-1]
- return file.Write(b)
-}
-
-// Pipe returns a connected pair of Files; reads from r return bytes written to w.
-// It returns the files and an Error, if any.
-func Pipe() (r *File, w *File, err Error) {
- var p [2]int
-
- // See ../syscall/exec.go for description of lock.
- syscall.ForkLock.RLock()
- e := syscall.Pipe(p[0:])
- if e != 0 {
- syscall.ForkLock.RUnlock()
- return nil, nil, NewSyscallError("pipe", e)
- }
- syscall.CloseOnExec(p[0])
- syscall.CloseOnExec(p[1])
- syscall.ForkLock.RUnlock()
-
- return NewFile(p[0], "|0"), NewFile(p[1], "|1"), nil
+ return file.Write([]byte(s))
}
// Mkdir creates a new directory with the specified name and permission bits.
// It returns an error, if any.
func Mkdir(name string, perm uint32) Error {
e := syscall.Mkdir(name, perm)
- if e != 0 {
+ if iserror(e) {
return &PathError{"mkdir", name, Errno(e)}
}
return nil
}
-// Stat returns a FileInfo structure describing the named file and an error, if any.
-// If name names a valid symbolic link, the returned FileInfo describes
-// the file pointed at by the link and has fi.FollowedSymlink set to true.
-// If name names an invalid symbolic link, the returned FileInfo describes
-// the link itself and has fi.FollowedSymlink set to false.
-func Stat(name string) (fi *FileInfo, err Error) {
- var lstat, stat syscall.Stat_t
- e := syscall.Lstat(name, &lstat)
- if e != 0 {
- return nil, &PathError{"stat", name, Errno(e)}
- }
- statp := &lstat
- if lstat.Mode&syscall.S_IFMT == syscall.S_IFLNK {
- e := syscall.Stat(name, &stat)
- if e == 0 {
- statp = &stat
- }
- }
- return fileInfoFromStat(name, new(FileInfo), &lstat, statp), nil
-}
-
-// Lstat returns the FileInfo structure describing the named file and an
-// error, if any. If the file is a symbolic link, the returned FileInfo
-// describes the symbolic link. Lstat makes no attempt to follow the link.
-func Lstat(name string) (fi *FileInfo, err Error) {
- var stat syscall.Stat_t
- e := syscall.Lstat(name, &stat)
- if e != 0 {
- return nil, &PathError{"lstat", name, Errno(e)}
- }
- return fileInfoFromStat(name, new(FileInfo), &stat, &stat), nil
-}
-
// Chdir changes the current working directory to the named directory.
func Chdir(dir string) Error {
- if e := syscall.Chdir(dir); e != 0 {
+ if e := syscall.Chdir(dir); iserror(e) {
return &PathError{"chdir", dir, Errno(e)}
}
return nil
// Chdir changes the current working directory to the file,
// which must be a directory.
func (f *File) Chdir() Error {
- if e := syscall.Fchdir(f.fd); e != 0 {
+ if e := syscall.Fchdir(f.fd); iserror(e) {
return &PathError{"chdir", f.name, Errno(e)}
}
return nil
}
-// Remove removes the named file or directory.
-func Remove(name string) Error {
- // System call interface forces us to know
- // whether name is a file or directory.
- // Try both: it is cheaper on average than
- // doing a Stat plus the right one.
- e := syscall.Unlink(name)
- if e == 0 {
- return nil
- }
- e1 := syscall.Rmdir(name)
- if e1 == 0 {
- return nil
- }
-
- // Both failed: figure out which error to return.
- // OS X and Linux differ on whether unlink(dir)
- // returns EISDIR, so can't use that. However,
- // both agree that rmdir(file) returns ENOTDIR,
- // so we can use that to decide which error is real.
- // Rmdir might also return ENOTDIR if given a bad
- // file path, like /etc/passwd/foo, but in that case,
- // both errors will be ENOTDIR, so it's okay to
- // use the error from unlink.
- // For windows syscall.ENOTDIR is set
- // to syscall.ERROR_DIRECTORY, hopefully it should
- // do the trick.
- if e1 != syscall.ENOTDIR {
- e = e1
- }
- return &PathError{"remove", name, Errno(e)}
-}
-
-// LinkError records an error during a link or symlink or rename
-// system call and the paths that caused it.
-type LinkError struct {
- Op string
- Old string
- New string
- Error Error
-}
-
-func (e *LinkError) String() string {
- return e.Op + " " + e.Old + " " + e.New + ": " + e.Error.String()
-}
-
-// Link creates a hard link.
-func Link(oldname, newname string) Error {
- e := syscall.Link(oldname, newname)
- if e != 0 {
- return &LinkError{"link", oldname, newname, Errno(e)}
- }
- return nil
-}
-
-// Symlink creates a symbolic link.
-func Symlink(oldname, newname string) Error {
- e := syscall.Symlink(oldname, newname)
- if e != 0 {
- return &LinkError{"symlink", oldname, newname, Errno(e)}
- }
- return nil
+// Open opens the named file for reading. If successful, methods on
+// the returned file can be used for reading; the associated file
+// descriptor has mode O_RDONLY.
+// It returns the File and an Error, if any.
+func Open(name string) (file *File, err Error) {
+ return OpenFile(name, O_RDONLY, 0)
}
-// Readlink reads the contents of a symbolic link: the destination of
-// the link. It returns the contents and an Error, if any.
-func Readlink(name string) (string, Error) {
- for len := 128; ; len *= 2 {
- b := make([]byte, len)
- n, e := syscall.Readlink(name, b)
- if e != 0 {
- return "", &PathError{"readlink", name, Errno(e)}
- }
- if n < len {
- return string(b[0:n]), nil
- }
- }
- // Silence 6g.
- return "", nil
-}
-
-// Rename renames a file.
-func Rename(oldname, newname string) Error {
- e := syscall.Rename(oldname, newname)
- if e != 0 {
- return &LinkError{"rename", oldname, newname, Errno(e)}
- }
- return nil
-}
-
-// Chmod changes the mode of the named file to mode.
-// If the file is a symbolic link, it changes the mode of the link's target.
-func Chmod(name string, mode uint32) Error {
- if e := syscall.Chmod(name, mode); e != 0 {
- return &PathError{"chmod", name, Errno(e)}
- }
- return nil
-}
-
-// Chmod changes the mode of the file to mode.
-func (f *File) Chmod(mode uint32) Error {
- if e := syscall.Fchmod(f.fd, mode); e != 0 {
- return &PathError{"chmod", f.name, Errno(e)}
- }
- return nil
-}
-
-// Chown changes the numeric uid and gid of the named file.
-// If the file is a symbolic link, it changes the uid and gid of the link's target.
-func Chown(name string, uid, gid int) Error {
- if e := syscall.Chown(name, uid, gid); e != 0 {
- return &PathError{"chown", name, Errno(e)}
- }
- return nil
-}
-
-// Lchown changes the numeric uid and gid of the named file.
-// If the file is a symbolic link, it changes the uid and gid of the link itself.
-func Lchown(name string, uid, gid int) Error {
- if e := syscall.Lchown(name, uid, gid); e != 0 {
- return &PathError{"lchown", name, Errno(e)}
- }
- return nil
-}
-
-// Chown changes the numeric uid and gid of the named file.
-func (f *File) Chown(uid, gid int) Error {
- if e := syscall.Fchown(f.fd, uid, gid); e != 0 {
- return &PathError{"chown", f.name, Errno(e)}
- }
- return nil
-}
-
-// Truncate changes the size of the file.
-// It does not change the I/O offset.
-func (f *File) Truncate(size int64) Error {
- if e := syscall.Ftruncate(f.fd, size); e != 0 {
- return &PathError{"truncate", f.name, Errno(e)}
- }
- return nil
-}
-
-// Sync commits the current contents of the file to stable storage.
-// Typically, this means flushing the file system's in-memory copy
-// of recently written data to disk.
-func (file *File) Sync() (err Error) {
- if file == nil {
- return EINVAL
- }
- if e := syscall.Fsync(file.fd); e != 0 {
- return NewSyscallError("fsync", e)
- }
- return nil
-}
-
-// Chtimes changes the access and modification times of the named
-// file, similar to the Unix utime() or utimes() functions.
-//
-// The argument times are in nanoseconds, although the underlying
-// filesystem may truncate or round the values to a more
-// coarse time unit.
-func Chtimes(name string, atime_ns int64, mtime_ns int64) Error {
- var utimes [2]syscall.Timeval
- utimes[0] = syscall.NsecToTimeval(atime_ns)
- utimes[1] = syscall.NsecToTimeval(mtime_ns)
- if e := syscall.Utimes(name, utimes[0:]); e != 0 {
- return &PathError{"chtimes", name, Errno(e)}
- }
- return nil
+// Create creates the named file mode 0666 (before umask), truncating
+// it if it already exists. If successful, methods on the returned
+// File can be used for I/O; the associated file descriptor has mode
+// O_RDWR.
+// It returns the File and an Error, if any.
+func Create(name string) (file *File, err Error) {
+ return OpenFile(name, O_RDWR|O_CREATE|O_TRUNC, 0666)
}
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