os: add support for long path names on unix RemoveAll

src/internal/syscall/unix/at.go

@@ -0,0 +1,58 @@
+// Copyright 2018 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.
+
+// +build linux darwin freebsd openbsd netbsd dragonfly
+
+package unix
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+func Unlinkat(dirfd int, path string, flags int) error {
+	var p *byte
+	p, err := syscall.BytePtrFromString(path)
+	if err != nil {
+		return err
+	}
+
+	_, _, errno := syscall.Syscall(unlinkatTrap, uintptr(dirfd), uintptr(unsafe.Pointer(p)), uintptr(flags))
+	if errno != 0 {
+		return errno
+	}
+
+	return nil
+}
+
+func Openat(dirfd int, path string, flags int, perm uint32) (int, error) {
+	var p *byte
+	p, err := syscall.BytePtrFromString(path)
+	if err != nil {
+		return 0, err
+	}
+
+	fd, _, errno := syscall.Syscall6(openatTrap, uintptr(dirfd), uintptr(unsafe.Pointer(p)), uintptr(flags), uintptr(perm), 0, 0)
+	if errno != 0 {
+		return 0, errno
+	}
+
+	return int(fd), nil
+}
+
+func Fstatat(dirfd int, path string, stat *syscall.Stat_t, flags int) error {
+	var p *byte
+	p, err := syscall.BytePtrFromString(path)
+	if err != nil {
+		return err
+	}
+
+	_, _, errno := syscall.Syscall6(fstatatTrap, uintptr(dirfd), uintptr(unsafe.Pointer(p)), uintptr(unsafe.Pointer(stat)), uintptr(flags), 0, 0)
+	if errno != 0 {
+		return errno
+	}
+
+	return nil
+
+}

src/internal/syscall/unix/at_sysnum_darwin.go

@@ -0,0 +1,12 @@
+// Copyright 2018 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.
+
+package unix
+
+const unlinkatTrap uintptr = 472
+const openatTrap uintptr = 463
+const fstatatTrap uintptr = 470
+
+const AT_REMOVEDIR = 0x80
+const AT_SYMLINK_NOFOLLOW = 0x0020

src/internal/syscall/unix/at_sysnum_dragonfly.go

@@ -0,0 +1,14 @@
+// Copyright 2018 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.
+
+package unix
+
+import "syscall"
+
+const unlinkatTrap uintptr = syscall.SYS_UNLINKAT
+const openatTrap uintptr = syscall.SYS_OPENAT
+const fstatatTrap uintptr = syscall.SYS_FSTATAT
+
+const AT_REMOVEDIR = 0x2
+const AT_SYMLINK_NOFOLLOW = 0x1

src/internal/syscall/unix/at_sysnum_freebsd.go

@@ -0,0 +1,14 @@
+// Copyright 2018 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.
+
+package unix
+
+import "syscall"
+
+const unlinkatTrap uintptr = syscall.SYS_UNLINKAT
+const openatTrap uintptr = syscall.SYS_OPENAT
+const fstatatTrap uintptr = syscall.SYS_FSTATAT
+
+const AT_REMOVEDIR = 0x800
+const AT_SYMLINK_NOFOLLOW = 0x200

src/internal/syscall/unix/at_sysnum_fstatat64_linux.go

@@ -0,0 +1,11 @@
+// Copyright 2018 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.
+
+// +build arm mips mipsle 386
+
+package unix
+
+import "syscall"
+
+const fstatatTrap uintptr = syscall.SYS_FSTATAT64

src/internal/syscall/unix/at_sysnum_fstatat_linux.go

@@ -0,0 +1,11 @@
+// Copyright 2018 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.
+
+// +build arm64
+
+package unix
+
+import "syscall"
+
+const fstatatTrap uintptr = syscall.SYS_FSTATAT

src/internal/syscall/unix/at_sysnum_linux.go

@@ -0,0 +1,13 @@
+// Copyright 2018 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.
+
+package unix
+
+import "syscall"
+
+const unlinkatTrap uintptr = syscall.SYS_UNLINKAT
+const openatTrap uintptr = syscall.SYS_OPENAT
+
+const AT_REMOVEDIR = 0x200
+const AT_SYMLINK_NOFOLLOW = 0x100

src/internal/syscall/unix/at_sysnum_netbsd.go

@@ -0,0 +1,14 @@
+// Copyright 2018 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.
+
+package unix
+
+import "syscall"
+
+const unlinkatTrap uintptr = syscall.SYS_UNLINKAT
+const openatTrap uintptr = syscall.SYS_OPENAT
+const fstatatTrap uintptr = syscall.SYS_FSTATAT
+
+const AT_REMOVEDIR = 0x800
+const AT_SYMLINK_NOFOLLOW = 0x200

src/internal/syscall/unix/at_sysnum_newfstatat_linux.go

@@ -0,0 +1,11 @@
+// Copyright 2018 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.
+
+// +build amd64 mips64 mips64le ppc64 ppc64le s390x
+
+package unix
+
+import "syscall"
+
+const fstatatTrap uintptr = syscall.SYS_NEWFSTATAT

src/internal/syscall/unix/at_sysnum_openbsd.go

@@ -0,0 +1,14 @@
+// Copyright 2018 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.
+
+package unix
+
+import "syscall"
+
+const unlinkatTrap uintptr = syscall.SYS_UNLINKAT
+const openatTrap uintptr = syscall.SYS_OPENAT
+const fstatatTrap uintptr = syscall.SYS_FSTATAT
+
+const AT_REMOVEDIR = 0x08
+const AT_SYMLINK_NOFOLLOW = 0x02

src/os/path.go

@@ -5,7 +5,6 @@
 package os
 
 import (
-	"io"
 	"syscall"
 )
 
@@ -58,101 +57,3 @@ func MkdirAll(path string, perm FileMode) error {
 	}
 	return nil
 }
-
-// RemoveAll removes path and any children it contains.
-// It removes everything it can but returns the first error
-// it encounters. If the path does not exist, RemoveAll
-// returns nil (no error).
-func RemoveAll(path string) error {
-	// Simple case: if Remove works, we're done.
-	err := Remove(path)
-	if err == nil || IsNotExist(err) {
-		return nil
-	}
-
-	// Otherwise, is this a directory we need to recurse into?
-	dir, serr := Lstat(path)
-	if serr != nil {
-		if serr, ok := serr.(*PathError); ok && (IsNotExist(serr.Err) || serr.Err == syscall.ENOTDIR) {
-			return nil
-		}
-		return serr
-	}
-	if !dir.IsDir() {
-		// Not a directory; return the error from Remove.
-		return err
-	}
-
-	// Remove contents & return first error.
-	err = nil
-	for {
-		fd, err := Open(path)
-		if err != nil {
-			if IsNotExist(err) {
-				// Already deleted by someone else.
-				return nil
-			}
-			return err
-		}
-
-		const request = 1024
-		names, err1 := fd.Readdirnames(request)
-
-		// Removing files from the directory may have caused
-		// the OS to reshuffle it. Simply calling Readdirnames
-		// again may skip some entries. The only reliable way
-		// to avoid this is to close and re-open the
-		// directory. See issue 20841.
-		fd.Close()
-
-		for _, name := range names {
-			err1 := RemoveAll(path + string(PathSeparator) + name)
-			if err == nil {
-				err = err1
-			}
-		}
-
-		if err1 == io.EOF {
-			break
-		}
-		// If Readdirnames returned an error, use it.
-		if err == nil {
-			err = err1
-		}
-		if len(names) == 0 {
-			break
-		}
-
-		// We don't want to re-open unnecessarily, so if we
-		// got fewer than request names from Readdirnames, try
-		// simply removing the directory now. If that
-		// succeeds, we are done.
-		if len(names) < request {
-			err1 := Remove(path)
-			if err1 == nil || IsNotExist(err1) {
-				return nil
-			}
-
-			if err != nil {
-				// We got some error removing the
-				// directory contents, and since we
-				// read fewer names than we requested
-				// there probably aren't more files to
-				// remove. Don't loop around to read
-				// the directory again. We'll probably
-				// just get the same error.
-				return err
-			}
-		}
-	}
-
-	// Remove directory.
-	err1 := Remove(path)
-	if err1 == nil || IsNotExist(err1) {
-		return nil
-	}
-	if err == nil {
-		err = err1
-	}
-	return err
-}