249 lines
7.0 KiB
Go
249 lines
7.0 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// The os package provides a platform-independent interface to operating
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// system functionality. The design is Unix-like.
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package os
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import (
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"syscall"
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)
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func sigpipe() // implemented in package runtime
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func epipecheck(file *File, e int) {
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if e == syscall.EPIPE {
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file.nepipe++
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if file.nepipe >= 10 {
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sigpipe()
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}
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} else {
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file.nepipe = 0
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}
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}
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// Pipe returns a connected pair of Files; reads from r return bytes written to w.
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// It returns the files and an Error, if any.
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func Pipe() (r *File, w *File, err Error) {
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var p [2]int
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// See ../syscall/exec.go for description of lock.
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syscall.ForkLock.RLock()
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e := syscall.Pipe(p[0:])
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if iserror(e) {
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syscall.ForkLock.RUnlock()
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return nil, nil, NewSyscallError("pipe", e)
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}
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syscall.CloseOnExec(p[0])
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syscall.CloseOnExec(p[1])
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syscall.ForkLock.RUnlock()
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return NewFile(p[0], "|0"), NewFile(p[1], "|1"), nil
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}
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// Stat returns a FileInfo structure describing the named file and an error, if any.
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// If name names a valid symbolic link, the returned FileInfo describes
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// the file pointed at by the link and has fi.FollowedSymlink set to true.
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// If name names an invalid symbolic link, the returned FileInfo describes
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// the link itself and has fi.FollowedSymlink set to false.
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func Stat(name string) (fi *FileInfo, err Error) {
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var lstat, stat syscall.Stat_t
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e := syscall.Lstat(name, &lstat)
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if iserror(e) {
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return nil, &PathError{"stat", name, Errno(e)}
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}
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statp := &lstat
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if lstat.Mode&syscall.S_IFMT == syscall.S_IFLNK {
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e := syscall.Stat(name, &stat)
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if !iserror(e) {
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statp = &stat
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}
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}
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return fileInfoFromStat(name, new(FileInfo), &lstat, statp), nil
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}
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// Lstat returns the FileInfo structure describing the named file and an
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// error, if any. If the file is a symbolic link, the returned FileInfo
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// describes the symbolic link. Lstat makes no attempt to follow the link.
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func Lstat(name string) (fi *FileInfo, err Error) {
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var stat syscall.Stat_t
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e := syscall.Lstat(name, &stat)
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if iserror(e) {
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return nil, &PathError{"lstat", name, Errno(e)}
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}
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return fileInfoFromStat(name, new(FileInfo), &stat, &stat), nil
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}
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// Remove removes the named file or directory.
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func Remove(name string) Error {
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// System call interface forces us to know
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// whether name is a file or directory.
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// Try both: it is cheaper on average than
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// doing a Stat plus the right one.
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e := syscall.Unlink(name)
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if !iserror(e) {
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return nil
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}
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e1 := syscall.Rmdir(name)
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if !iserror(e1) {
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return nil
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}
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// Both failed: figure out which error to return.
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// OS X and Linux differ on whether unlink(dir)
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// returns EISDIR, so can't use that. However,
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// both agree that rmdir(file) returns ENOTDIR,
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// so we can use that to decide which error is real.
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// Rmdir might also return ENOTDIR if given a bad
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// file path, like /etc/passwd/foo, but in that case,
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// both errors will be ENOTDIR, so it's okay to
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// use the error from unlink.
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// For windows syscall.ENOTDIR is set
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// to syscall.ERROR_DIRECTORY, hopefully it should
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// do the trick.
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if e1 != syscall.ENOTDIR {
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e = e1
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}
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return &PathError{"remove", name, Errno(e)}
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}
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// LinkError records an error during a link or symlink or rename
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// system call and the paths that caused it.
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type LinkError struct {
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Op string
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Old string
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New string
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Error Error
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}
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func (e *LinkError) String() string {
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return e.Op + " " + e.Old + " " + e.New + ": " + e.Error.String()
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}
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// Link creates a hard link.
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func Link(oldname, newname string) Error {
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e := syscall.Link(oldname, newname)
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if iserror(e) {
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return &LinkError{"link", oldname, newname, Errno(e)}
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}
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return nil
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}
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// Symlink creates a symbolic link.
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func Symlink(oldname, newname string) Error {
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e := syscall.Symlink(oldname, newname)
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if iserror(e) {
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return &LinkError{"symlink", oldname, newname, Errno(e)}
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}
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return nil
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}
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// Readlink reads the contents of a symbolic link: the destination of
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// the link. It returns the contents and an Error, if any.
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func Readlink(name string) (string, Error) {
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for len := 128; ; len *= 2 {
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b := make([]byte, len)
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n, e := syscall.Readlink(name, b)
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if iserror(e) {
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return "", &PathError{"readlink", name, Errno(e)}
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}
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if n < len {
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return string(b[0:n]), nil
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}
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}
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// Silence 6g.
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return "", nil
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}
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// Rename renames a file.
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func Rename(oldname, newname string) Error {
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e := syscall.Rename(oldname, newname)
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if iserror(e) {
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return &LinkError{"rename", oldname, newname, Errno(e)}
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}
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return nil
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}
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// Chmod changes the mode of the named file to mode.
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// If the file is a symbolic link, it changes the mode of the link's target.
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func Chmod(name string, mode uint32) Error {
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if e := syscall.Chmod(name, mode); iserror(e) {
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return &PathError{"chmod", name, Errno(e)}
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}
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return nil
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}
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// Chmod changes the mode of the file to mode.
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func (f *File) Chmod(mode uint32) Error {
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if e := syscall.Fchmod(f.fd, mode); iserror(e) {
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return &PathError{"chmod", f.name, Errno(e)}
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}
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return nil
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}
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// Chown changes the numeric uid and gid of the named file.
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// If the file is a symbolic link, it changes the uid and gid of the link's target.
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func Chown(name string, uid, gid int) Error {
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if e := syscall.Chown(name, uid, gid); iserror(e) {
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return &PathError{"chown", name, Errno(e)}
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}
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return nil
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}
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// Lchown changes the numeric uid and gid of the named file.
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// If the file is a symbolic link, it changes the uid and gid of the link itself.
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func Lchown(name string, uid, gid int) Error {
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if e := syscall.Lchown(name, uid, gid); iserror(e) {
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return &PathError{"lchown", name, Errno(e)}
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}
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return nil
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}
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// Chown changes the numeric uid and gid of the named file.
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func (f *File) Chown(uid, gid int) Error {
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if e := syscall.Fchown(f.fd, uid, gid); iserror(e) {
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return &PathError{"chown", f.name, Errno(e)}
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}
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return nil
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}
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// Truncate changes the size of the file.
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// It does not change the I/O offset.
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func (f *File) Truncate(size int64) Error {
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if e := syscall.Ftruncate(f.fd, size); iserror(e) {
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return &PathError{"truncate", f.name, Errno(e)}
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}
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return nil
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}
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// Sync commits the current contents of the file to stable storage.
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// Typically, this means flushing the file system's in-memory copy
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// of recently written data to disk.
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func (file *File) Sync() (err Error) {
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if file == nil {
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return EINVAL
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}
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if e := syscall.Fsync(file.fd); iserror(e) {
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return NewSyscallError("fsync", e)
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}
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return nil
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}
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// Chtimes changes the access and modification times of the named
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// file, similar to the Unix utime() or utimes() functions.
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//
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// The argument times are in nanoseconds, although the underlying
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// filesystem may truncate or round the values to a more
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// coarse time unit.
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func Chtimes(name string, atime_ns int64, mtime_ns int64) Error {
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var utimes [2]syscall.Timeval
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utimes[0] = syscall.NsecToTimeval(atime_ns)
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utimes[1] = syscall.NsecToTimeval(mtime_ns)
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if e := syscall.Utimes(name, utimes[0:]); iserror(e) {
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return &PathError{"chtimes", name, Errno(e)}
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}
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return nil
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}
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