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windows: fixes unlinking symlink to dir, rmdir on opened empty dir. (#1172)

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Signed-off-by: Takeshi Yoneda <takeshi@tetrate.io>
This commit is contained in:
Takeshi Yoneda
2023-02-26 23:23:54 -08:00
committed by GitHub
parent 75aa6b2a6e
commit d955cd7a13
7 changed files with 213 additions and 19 deletions
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14
internal/platform/open_file_windows.go
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@@ -3,6 +3,8 @@ package platform
import (
"io/fs"
"os"
"runtime"
"strings"
"syscall"
"unsafe"
)
@@ -140,6 +142,18 @@ func open(path string, mode int, perm uint32) (fd syscall.Handle, err error) {
}
}
}
if isGo120 {
// This shouldn't be included before 1.20 to have consistent behavior.
// https://github.com/golang/go/commit/0f0aa5d8a6a0253627d58b3aa083b24a1091933f
if createmode == syscall.OPEN_EXISTING && access == syscall.GENERIC_READ {
// Necessary for opening directory handles.
attrs |= syscall.FILE_FLAG_BACKUP_SEMANTICS
}
}
h, e := syscall.CreateFile(pathp, access, sharemode, sa, createmode, attrs, 0)
return h, e
}
var isGo120 = strings.Contains(runtime.Version(), "go1.20")

13
internal/platform/unlink.go Normal file
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@@ -0,0 +1,13 @@
//go:build !windows
package platform
import "syscall"
func Unlink(name string) error {
err := syscall.Unlink(name)
if err = UnwrapOSError(err); err == syscall.EPERM {
err = syscall.EISDIR
}
return err
}

58
internal/platform/unlink_test.go Normal file
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@@ -0,0 +1,58 @@
package platform
import (
"os"
"path"
"syscall"
"testing"
"github.com/tetratelabs/wazero/internal/testing/require"
)
func TestUnlink(t *testing.T) {
t.Run("doesn't exist", func(t *testing.T) {
name := "non-existent"
err := Unlink(name)
require.EqualErrno(t, syscall.ENOENT, err)
})
t.Run("target: dir", func(t *testing.T) {
tmpDir := t.TempDir()
dir := path.Join(tmpDir, "dir")
require.NoError(t, os.Mkdir(dir, 0o700))
err := Unlink(dir)
require.EqualErrno(t, syscall.EISDIR, err)
require.NoError(t, os.Remove(dir))
})
t.Run("target: symlink to dir", func(t *testing.T) {
tmpDir := t.TempDir()
// Create link target dir.
subDirRealPath := path.Join(tmpDir, "subdir")
require.NoError(t, os.Mkdir(subDirRealPath, 0o700))
// Create a symlink to the subdirectory.
const symlinkName = "symlink-to-dir"
require.NoError(t, os.Symlink("subdir", symlinkName))
// Unlinking the symlink should suceed.
err := Unlink(symlinkName)
require.NoError(t, err)
})
t.Run("file exists", func(t *testing.T) {
tmpDir := t.TempDir()
name := path.Join(tmpDir, "unlink")
require.NoError(t, os.WriteFile(name, []byte{}, 0o600))
require.NoError(t, Unlink(name))
_, err := os.Stat(name)
require.Error(t, err)
})
}

25
internal/platform/unlink_windows.go Normal file
View File

@@ -0,0 +1,25 @@
//go:build windows
package platform
import (
"os"
"syscall"
)
func Unlink(name string) (err error) {
err = syscall.Unlink(name)
if err == nil {
return
}
err = UnwrapOSError(err)
if err == syscall.EPERM {
lstat, errLstat := os.Lstat(name)
if errLstat == nil && lstat.Mode()&os.ModeSymlink != 0 {
err = UnwrapOSError(os.Remove(name))
} else {
err = syscall.EISDIR
}
}
return
}

6
internal/sysfs/dirfs.go
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@@ -110,11 +110,7 @@ func (d *dirFS) Rmdir(name string) error {
// Unlink implements FS.Unlink
func (d *dirFS) Unlink(name string) (err error) {
err = syscall.Unlink(d.join(name))
if err = platform.UnwrapOSError(err); err == syscall.EPERM {
err = syscall.EISDIR
}
return
return platform.Unlink(d.join(name))
}
// Symlink implements FS.Symlink

110
internal/sysfs/dirfs_test.go
View File

@@ -336,18 +336,23 @@ func TestDirFS_Rename(t *testing.T) {
}
func TestDirFS_Rmdir(t *testing.T) {
tmpDir := t.TempDir()
testFS := NewDirFS(tmpDir)
name := "rmdir"
realPath := pathutil.Join(tmpDir, name)
t.Run("doesn't exist", func(t *testing.T) {
tmpDir := t.TempDir()
testFS := NewDirFS(tmpDir)
name := "rmdir"
err := testFS.Rmdir(name)
require.EqualErrno(t, syscall.ENOENT, err)
})
t.Run("dir not empty", func(t *testing.T) {
tmpDir := t.TempDir()
testFS := NewDirFS(tmpDir)
name := "rmdir"
realPath := pathutil.Join(tmpDir, name)
require.NoError(t, os.Mkdir(realPath, 0o700))
fileInDir := pathutil.Join(realPath, "file")
require.NoError(t, os.WriteFile(fileInDir, []byte{}, 0o600))
@@ -358,13 +363,62 @@ func TestDirFS_Rmdir(t *testing.T) {
require.NoError(t, os.Remove(fileInDir))
})
t.Run("dir previously not empty", func(t *testing.T) {
tmpDir := t.TempDir()
testFS := NewDirFS(tmpDir)
name := "rmdir"
realPath := pathutil.Join(tmpDir, name)
require.NoError(t, os.Mkdir(realPath, 0o700))
// Create a file and then delete it.
fileInDir := pathutil.Join(realPath, "file")
require.NoError(t, os.WriteFile(fileInDir, []byte{}, 0o600))
require.NoError(t, os.Remove(fileInDir))
// After deletion, try removing directory.
err := testFS.Rmdir(name)
require.NoError(t, err)
})
t.Run("dir empty", func(t *testing.T) {
tmpDir := t.TempDir()
testFS := NewDirFS(tmpDir)
name := "rmdir"
realPath := pathutil.Join(tmpDir, name)
require.NoError(t, os.Mkdir(realPath, 0o700))
require.NoError(t, testFS.Rmdir(name))
_, err := os.Stat(realPath)
require.Error(t, err)
})
t.Run("dir empty while opening", func(t *testing.T) {
tmpDir := t.TempDir()
testFS := NewDirFS(tmpDir)
name := "rmdir"
realPath := pathutil.Join(tmpDir, name)
require.NoError(t, os.Mkdir(realPath, 0o700))
f, err := testFS.OpenFile(name, platform.O_DIRECTORY, 0o700)
require.NoError(t, err)
defer func() {
require.NoError(t, f.Close())
}()
require.NoError(t, testFS.Rmdir(name))
_, err = os.Stat(realPath)
require.Error(t, err)
})
t.Run("not directory", func(t *testing.T) {
tmpDir := t.TempDir()
testFS := NewDirFS(tmpDir)
name := "rmdir"
realPath := pathutil.Join(tmpDir, name)
require.NoError(t, os.WriteFile(realPath, []byte{}, 0o600))
err := testFS.Rmdir(name)
@@ -375,27 +429,55 @@ func TestDirFS_Rmdir(t *testing.T) {
}
func TestDirFS_Unlink(t *testing.T) {
tmpDir := t.TempDir()
testFS := NewDirFS(tmpDir)
name := "unlink"
realPath := pathutil.Join(tmpDir, name)
t.Run("doesn't exist", func(t *testing.T) {
tmpDir := t.TempDir()
testFS := NewDirFS(tmpDir)
name := "unlink"
err := testFS.Unlink(name)
require.EqualErrno(t, syscall.ENOENT, err)
})
t.Run("not file", func(t *testing.T) {
t.Run("target: dir", func(t *testing.T) {
tmpDir := t.TempDir()
testFS := NewDirFS(tmpDir)
dir := "dir"
realPath := pathutil.Join(tmpDir, dir)
require.NoError(t, os.Mkdir(realPath, 0o700))
err := testFS.Unlink(name)
err := testFS.Unlink(dir)
require.EqualErrno(t, syscall.EISDIR, err)
require.NoError(t, os.Remove(realPath))
})
t.Run("target: symlink to dir", func(t *testing.T) {
tmpDir := t.TempDir()
testFS := NewDirFS(tmpDir)
// Create link target dir.
subDirName := "subdir"
subDirRealPath := pathutil.Join(tmpDir, subDirName)
require.NoError(t, os.Mkdir(subDirRealPath, 0o700))
// Create a symlink to the subdirectory.
const symlinkName = "symlink-to-dir"
require.NoError(t, testFS.Symlink("subdir", symlinkName))
// Unlinking the symlink should suceed.
err := testFS.Unlink(symlinkName)
require.NoError(t, err)
})
t.Run("file exists", func(t *testing.T) {
tmpDir := t.TempDir()
testFS := NewDirFS(tmpDir)
name := "unlink"
realPath := pathutil.Join(tmpDir, name)
require.NoError(t, os.WriteFile(realPath, []byte{}, 0o600))
require.NoError(t, testFS.Unlink(name))

6
internal/sysfs/sysfs.go
View File

@@ -153,6 +153,12 @@ type FS interface {
// - syscall.EINVAL: `path` is invalid.
// - syscall.ENOENT: `path` doesn't exist.
// - syscall.EISDIR: `path` exists, but is a directory.
//
// # Notes
//
// - On Windows, syscall.Unlink doesn't delete symlink to directory unlike other platforms. Implementations might
// want to combine syscall.RemoveDirectory with syscall.Unlink in order to delete such links on Windows.
// See https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-removedirectorya
Unlink(path string) error
// Link is similar to syscall.Link, except the path is relative to this