1 files changed, 464 insertions, 0 deletions
diff --git a/src/os/file_unix.go b/src/os/file_unix.go
new file mode 100644
index 0000000..6796c8d
--- /dev/null
+++ b/src/os/file_unix.go
@@ -0,0 +1,464 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build unix || (js && wasm)
+
+package os
+
+import (
+	"internal/poll"
+	"internal/syscall/unix"
+	"runtime"
+	"syscall"
+	_ "unsafe" // for go:linkname
+)
+
+// fixLongPath is a noop on non-Windows platforms.
+func fixLongPath(path string) string {
+	return path
+}
+
+func rename(oldname, newname string) error {
+	fi, err := Lstat(newname)
+	if err == nil && fi.IsDir() {
+		// There are two independent errors this function can return:
+		// one for a bad oldname, and one for a bad newname.
+		// At this point we've determined the newname is bad.
+		// But just in case oldname is also bad, prioritize returning
+		// the oldname error because that's what we did historically.
+		// However, if the old name and new name are not the same, yet
+		// they refer to the same file, it implies a case-only
+		// rename on a case-insensitive filesystem, which is ok.
+		if ofi, err := Lstat(oldname); err != nil {
+			if pe, ok := err.(*PathError); ok {
+				err = pe.Err
+			}
+			return &LinkError{"rename", oldname, newname, err}
+		} else if newname == oldname || !SameFile(fi, ofi) {
+			return &LinkError{"rename", oldname, newname, syscall.EEXIST}
+		}
+	}
+	err = ignoringEINTR(func() error {
+		return syscall.Rename(oldname, newname)
+	})
+	if err != nil {
+		return &LinkError{"rename", oldname, newname, err}
+	}
+	return nil
+}
+
+// file is the real representation of *File.
+// The extra level of indirection ensures that no clients of os
+// can overwrite this data, which could cause the finalizer
+// to close the wrong file descriptor.
+type file struct {
+	pfd         poll.FD
+	name        string
+	dirinfo     *dirInfo // nil unless directory being read
+	nonblock    bool     // whether we set nonblocking mode
+	stdoutOrErr bool     // whether this is stdout or stderr
+	appendMode  bool     // whether file is opened for appending
+}
+
+// Fd returns the integer Unix file descriptor referencing the open file.
+// If f is closed, the file descriptor becomes invalid.
+// If f is garbage collected, a finalizer may close the file descriptor,
+// making it invalid; see runtime.SetFinalizer for more information on when
+// a finalizer might be run. On Unix systems this will cause the SetDeadline
+// methods to stop working.
+// Because file descriptors can be reused, the returned file descriptor may
+// only be closed through the Close method of f, or by its finalizer during
+// garbage collection. Otherwise, during garbage collection the finalizer
+// may close an unrelated file descriptor with the same (reused) number.
+//
+// As an alternative, see the f.SyscallConn method.
+func (f *File) Fd() uintptr {
+	if f == nil {
+		return ^(uintptr(0))
+	}
+
+	// If we put the file descriptor into nonblocking mode,
+	// then set it to blocking mode before we return it,
+	// because historically we have always returned a descriptor
+	// opened in blocking mode. The File will continue to work,
+	// but any blocking operation will tie up a thread.
+	if f.nonblock {
+		f.pfd.SetBlocking()
+	}
+
+	return uintptr(f.pfd.Sysfd)
+}
+
+// NewFile returns a new File with the given file descriptor and
+// name. The returned value will be nil if fd is not a valid file
+// descriptor. On Unix systems, if the file descriptor is in
+// non-blocking mode, NewFile will attempt to return a pollable File
+// (one for which the SetDeadline methods work).
+//
+// After passing it to NewFile, fd may become invalid under the same
+// conditions described in the comments of the Fd method, and the same
+// constraints apply.
+func NewFile(fd uintptr, name string) *File {
+	kind := kindNewFile
+	if nb, err := unix.IsNonblock(int(fd)); err == nil && nb {
+		kind = kindNonBlock
+	}
+	return newFile(fd, name, kind)
+}
+
+// net_newUnixFile is a hidden entry point called by net.conn.File.
+// This is used so that a nonblocking network connection will become
+// blocking if code calls the Fd method. We don't want that for direct
+// calls to NewFile: passing a nonblocking descriptor to NewFile should
+// remain nonblocking if you get it back using Fd. But for net.conn.File
+// the call to NewFile is hidden from the user. Historically in that case
+// the Fd method has returned a blocking descriptor, and we want to
+// retain that behavior because existing code expects it and depends on it.
+//
+//go:linkname net_newUnixFile net.newUnixFile
+func net_newUnixFile(fd uintptr, name string) *File {
+	f := newFile(fd, name, kindNonBlock)
+	f.nonblock = true // tell Fd to return blocking descriptor
+	return f
+}
+
+// newFileKind describes the kind of file to newFile.
+type newFileKind int
+
+const (
+	kindNewFile newFileKind = iota
+	kindOpenFile
+	kindPipe
+	kindNonBlock
+)
+
+// newFile is like NewFile, but if called from OpenFile or Pipe
+// (as passed in the kind parameter) it tries to add the file to
+// the runtime poller.
+func newFile(fd uintptr, name string, kind newFileKind) *File {
+	fdi := int(fd)
+	if fdi < 0 {
+		return nil
+	}
+	f := &File{&file{
+		pfd: poll.FD{
+			Sysfd:         fdi,
+			IsStream:      true,
+			ZeroReadIsEOF: true,
+		},
+		name:        name,
+		stdoutOrErr: fdi == 1 || fdi == 2,
+	}}
+
+	pollable := kind == kindOpenFile || kind == kindPipe || kind == kindNonBlock
+
+	// If the caller passed a non-blocking filedes (kindNonBlock),
+	// we assume they know what they are doing so we allow it to be
+	// used with kqueue.
+	if kind == kindOpenFile {
+		switch runtime.GOOS {
+		case "darwin", "ios", "dragonfly", "freebsd", "netbsd", "openbsd":
+			var st syscall.Stat_t
+			err := ignoringEINTR(func() error {
+				return syscall.Fstat(fdi, &st)
+			})
+			typ := st.Mode & syscall.S_IFMT
+			// Don't try to use kqueue with regular files on *BSDs.
+			// On FreeBSD a regular file is always
+			// reported as ready for writing.
+			// On Dragonfly, NetBSD and OpenBSD the fd is signaled
+			// only once as ready (both read and write).
+			// Issue 19093.
+			// Also don't add directories to the netpoller.
+			if err == nil && (typ == syscall.S_IFREG || typ == syscall.S_IFDIR) {
+				pollable = false
+			}
+
+			// In addition to the behavior described above for regular files,
+			// on Darwin, kqueue does not work properly with fifos:
+			// closing the last writer does not cause a kqueue event
+			// for any readers. See issue #24164.
+			if (runtime.GOOS == "darwin" || runtime.GOOS == "ios") && typ == syscall.S_IFIFO {
+				pollable = false
+			}
+		}
+	}
+
+	clearNonBlock := false
+	if pollable {
+		if kind == kindNonBlock {
+			// The descriptor is already in non-blocking mode.
+			// We only set f.nonblock if we put the file into
+			// non-blocking mode.
+		} else if err := syscall.SetNonblock(fdi, true); err == nil {
+			f.nonblock = true
+			clearNonBlock = true
+		} else {
+			pollable = false
+		}
+	}
+
+	// An error here indicates a failure to register
+	// with the netpoll system. That can happen for
+	// a file descriptor that is not supported by
+	// epoll/kqueue; for example, disk files on
+	// Linux systems. We assume that any real error
+	// will show up in later I/O.
+	// We do restore the blocking behavior if it was set by us.
+	if pollErr := f.pfd.Init("file", pollable); pollErr != nil && clearNonBlock {
+		if err := syscall.SetNonblock(fdi, false); err == nil {
+			f.nonblock = false
+		}
+	}
+
+	runtime.SetFinalizer(f.file, (*file).close)
+	return f
+}
+
+// epipecheck raises SIGPIPE if we get an EPIPE error on standard
+// output or standard error. See the SIGPIPE docs in os/signal, and
+// issue 11845.
+func epipecheck(file *File, e error) {
+	if e == syscall.EPIPE && file.stdoutOrErr {
+		sigpipe()
+	}
+}
+
+// DevNull is the name of the operating system's “null device.”
+// On Unix-like systems, it is "/dev/null"; on Windows, "NUL".
+const DevNull = "/dev/null"
+
+// openFileNolog is the Unix implementation of OpenFile.
+// Changes here should be reflected in openFdAt, if relevant.
+func openFileNolog(name string, flag int, perm FileMode) (*File, error) {
+	setSticky := false
+	if !supportsCreateWithStickyBit && flag&O_CREATE != 0 && perm&ModeSticky != 0 {
+		if _, err := Stat(name); IsNotExist(err) {
+			setSticky = true
+		}
+	}
+
+	var r int
+	for {
+		var e error
+		r, e = syscall.Open(name, flag|syscall.O_CLOEXEC, syscallMode(perm))
+		if e == nil {
+			break
+		}
+
+		// We have to check EINTR here, per issues 11180 and 39237.
+		if e == syscall.EINTR {
+			continue
+		}
+
+		return nil, &PathError{Op: "open", Path: name, Err: e}
+	}
+
+	// open(2) itself won't handle the sticky bit on *BSD and Solaris
+	if setSticky {
+		setStickyBit(name)
+	}
+
+	// There's a race here with fork/exec, which we are
+	// content to live with. See ../syscall/exec_unix.go.
+	if !supportsCloseOnExec {
+		syscall.CloseOnExec(r)
+	}
+
+	kind := kindOpenFile
+	if unix.HasNonblockFlag(flag) {
+		kind = kindNonBlock
+	}
+
+	return newFile(uintptr(r), name, kind), nil
+}
+
+func (file *file) close() error {
+	if file == nil {
+		return syscall.EINVAL
+	}
+	if file.dirinfo != nil {
+		file.dirinfo.close()
+		file.dirinfo = nil
+	}
+	var err error
+	if e := file.pfd.Close(); e != nil {
+		if e == poll.ErrFileClosing {
+			e = ErrClosed
+		}
+		err = &PathError{Op: "close", Path: file.name, Err: e}
+	}
+
+	// no need for a finalizer anymore
+	runtime.SetFinalizer(file, nil)
+	return err
+}
+
+// seek sets the offset for the next Read or Write on file to offset, interpreted
+// according to whence: 0 means relative to the origin of the file, 1 means
+// relative to the current offset, and 2 means relative to the end.
+// It returns the new offset and an error, if any.
+func (f *File) seek(offset int64, whence int) (ret int64, err error) {
+	if f.dirinfo != nil {
+		// Free cached dirinfo, so we allocate a new one if we
+		// access this file as a directory again. See #35767 and #37161.
+		f.dirinfo.close()
+		f.dirinfo = nil
+	}
+	ret, err = f.pfd.Seek(offset, whence)
+	runtime.KeepAlive(f)
+	return ret, err
+}
+
+// Truncate changes the size of the named file.
+// If the file is a symbolic link, it changes the size of the link's target.
+// If there is an error, it will be of type *PathError.
+func Truncate(name string, size int64) error {
+	e := ignoringEINTR(func() error {
+		return syscall.Truncate(name, size)
+	})
+	if e != nil {
+		return &PathError{Op: "truncate", Path: name, Err: e}
+	}
+	return nil
+}
+
+// Remove removes the named file or (empty) directory.
+// If there is an error, it will be of type *PathError.
+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 := ignoringEINTR(func() error {
+		return syscall.Unlink(name)
+	})
+	if e == nil {
+		return nil
+	}
+	e1 := ignoringEINTR(func() error {
+		return syscall.Rmdir(name)
+	})
+	if e1 == nil {
+		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.
+	if e1 != syscall.ENOTDIR {
+		e = e1
+	}
+	return &PathError{Op: "remove", Path: name, Err: e}
+}
+
+func tempDir() string {
+	dir := Getenv("TMPDIR")
+	if dir == "" {
+		if runtime.GOOS == "android" {
+			dir = "/data/local/tmp"
+		} else {
+			dir = "/tmp"
+		}
+	}
+	return dir
+}
+
+// Link creates newname as a hard link to the oldname file.
+// If there is an error, it will be of type *LinkError.
+func Link(oldname, newname string) error {
+	e := ignoringEINTR(func() error {
+		return syscall.Link(oldname, newname)
+	})
+	if e != nil {
+		return &LinkError{"link", oldname, newname, e}
+	}
+	return nil
+}
+
+// Symlink creates newname as a symbolic link to oldname.
+// On Windows, a symlink to a non-existent oldname creates a file symlink;
+// if oldname is later created as a directory the symlink will not work.
+// If there is an error, it will be of type *LinkError.
+func Symlink(oldname, newname string) error {
+	e := ignoringEINTR(func() error {
+		return syscall.Symlink(oldname, newname)
+	})
+	if e != nil {
+		return &LinkError{"symlink", oldname, newname, e}
+	}
+	return nil
+}
+
+// Readlink returns the destination of the named symbolic link.
+// If there is an error, it will be of type *PathError.
+func Readlink(name string) (string, error) {
+	for len := 128; ; len *= 2 {
+		b := make([]byte, len)
+		var (
+			n int
+			e error
+		)
+		for {
+			n, e = fixCount(syscall.Readlink(name, b))
+			if e != syscall.EINTR {
+				break
+			}
+		}
+		// buffer too small
+		if runtime.GOOS == "aix" && e == syscall.ERANGE {
+			continue
+		}
+		if e != nil {
+			return "", &PathError{Op: "readlink", Path: name, Err: e}
+		}
+		if n < len {
+			return string(b[0:n]), nil
+		}
+	}
+}
+
+type unixDirent struct {
+	parent string
+	name   string
+	typ    FileMode
+	info   FileInfo
+}
+
+func (d *unixDirent) Name() string   { return d.name }
+func (d *unixDirent) IsDir() bool    { return d.typ.IsDir() }
+func (d *unixDirent) Type() FileMode { return d.typ }
+
+func (d *unixDirent) Info() (FileInfo, error) {
+	if d.info != nil {
+		return d.info, nil
+	}
+	return lstat(d.parent + "/" + d.name)
+}
+
+func newUnixDirent(parent, name string, typ FileMode) (DirEntry, error) {
+	ude := &unixDirent{
+		parent: parent,
+		name:   name,
+		typ:    typ,
+	}
+	if typ != ^FileMode(0) && !testingForceReadDirLstat {
+		return ude, nil
+	}
+
+	info, err := lstat(parent + "/" + name)
+	if err != nil {
+		return nil, err
+	}
+
+	ude.typ = info.Mode().Type()
+	ude.info = info
+	return ude, nil
+}