syscallcompat: Drop Renameat emulation on macOS.

6 files changed, 42 insertions, 92 deletions

diff --git a/internal/syscallcompat/emulate.go b/internal/syscallcompat/emulate.go
index 35e17c6..7fea3a8 100644
--- a/internal/syscallcompat/emulate.go
+++ b/internal/syscallcompat/emulate.go
@@ -11,34 +11,6 @@ import (
 
 var chdirMutex sync.Mutex
 
-// emulateRenameat emulates the syscall for platforms that don't have it
-// in the kernel (darwin).
-func emulateRenameat(olddirfd int, oldpath string, newdirfd int, newpath string) error {
-	chdirMutex.Lock()
-	defer chdirMutex.Unlock()
-	// Unless both paths are absolute we have to save the old working dir and
-	// Chdir(oldWd) back to it in the end. If we error out before the first
-	// chdir, Chdir(oldWd) is unneccassary but does no harm.
-	if !filepath.IsAbs(oldpath) || !filepath.IsAbs(newpath) {
-		oldWd, err := os.Getwd()
-		if err != nil {
-			return err
-		}
-		defer os.Chdir(oldWd)
-	}
-	// Make oldpath absolute
-	oldpath, err := dirfdAbs(olddirfd, oldpath)
-	if err != nil {
-		return err
-	}
-	// Make newpath absolute
-	newpath, err = dirfdAbs(newdirfd, newpath)
-	if err != nil {
-		return err
-	}
-	return syscall.Rename(oldpath, newpath)
-}
-
 // emulateUnlinkat emulates the syscall for platforms that don't have it
 // in the kernel (darwin).
 func emulateUnlinkat(dirfd int, path string, flags int) (err error) {
@@ -82,24 +54,6 @@ func emulateMknodat(dirfd int, path string, mode uint32, dev int) error {
 	return syscall.Mknod(path, mode, dev)
 }
 
-// dirfdAbs transforms the dirfd-relative "path" to an absolute one. If the
-// path is not already absolute, this function will change the working
-// directory. The caller has to chdir back.
-func dirfdAbs(dirfd int, path string) (string, error) {
-	if filepath.IsAbs(path) {
-		return path, nil
-	}
-	err := syscall.Fchdir(dirfd)
-	if err != nil {
-		return "", err
-	}
-	wd, err := os.Getwd()
-	if err != nil {
-		return "", err
-	}
-	return filepath.Join(wd, path), nil
-}
-
 // emulateFchmodat emulates the syscall for platforms that don't have it
 // in the kernel (darwin).
 func emulateFchmodat(dirfd int, path string, mode uint32, flags int) (err error) {
diff --git a/internal/syscallcompat/emulate_test.go b/internal/syscallcompat/emulate_test.go
index 9b1994b..7d34c0c 100644
--- a/internal/syscallcompat/emulate_test.go
+++ b/internal/syscallcompat/emulate_test.go
@@ -9,43 +9,6 @@ import (
 	"golang.org/x/sys/unix"
 )
 
-func TestEmulateRenameat(t *testing.T) {
-	os.Mkdir(tmpDir+"/dir1", 0700)
-	dir1, err := os.Open(tmpDir + "/dir1")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer dir1.Close()
-	os.Mkdir(tmpDir+"/dir2", 0700)
-	dir2, err := os.Open(tmpDir + "/dir2")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer dir2.Close()
-	fd, err := os.Create(tmpDir + "/dir1/f1")
-	if err != nil {
-		t.Fatal(err)
-	}
-	fd.Close()
-	err = emulateRenameat(int(dir1.Fd()), "f1", int(dir2.Fd()), "f2")
-	if err != nil {
-		t.Fatal(err)
-	}
-	_, err = os.Stat(tmpDir + "/dir2/f2")
-	if err != nil {
-		t.Fatal(err)
-	}
-	// Test with absolute path
-	err = emulateRenameat(-1, tmpDir+"/dir2/f2", -1, tmpDir+"/dir2/f1")
-	if err != nil {
-		t.Fatal(err)
-	}
-	_, err = os.Stat(tmpDir + "/dir2/f1")
-	if err != nil {
-		t.Fatal(err)
-	}
-}
-
 func TestEmulateUnlinkat(t *testing.T) {
 	os.Mkdir(tmpDir+"/unlink1", 0700)
 	dirfd, err := os.Open(tmpDir + "/unlink1")
diff --git a/internal/syscallcompat/sys_common.go b/internal/syscallcompat/sys_common.go
index a5b2c05..d4b2e0d 100644
--- a/internal/syscallcompat/sys_common.go
+++ b/internal/syscallcompat/sys_common.go
@@ -62,6 +62,11 @@ func Openat(dirfd int, path string, flags int, mode uint32) (fd int, err error)
 	return unix.Openat(dirfd, path, flags, mode)
 }
 
+// Renameat wraps the Renameat syscall.
+func Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error) {
+	return unix.Renameat(olddirfd, oldpath, newdirfd, newpath)
+}
+
 // Linkat exists both in Linux and in MacOS 10.10+.
 func Linkat(olddirfd int, oldpath string, newdirfd int, newpath string, flags int) (err error) {
 	return unix.Linkat(olddirfd, oldpath, newdirfd, newpath, flags)
diff --git a/internal/syscallcompat/sys_common_test.go b/internal/syscallcompat/sys_common_test.go
index db6719e..3e38eb2 100644
--- a/internal/syscallcompat/sys_common_test.go
+++ b/internal/syscallcompat/sys_common_test.go
@@ -63,6 +63,43 @@ func TestOpenat(t *testing.T) {
 	}
 }
 
+func TestRenameat(t *testing.T) {
+	os.Mkdir(tmpDir+"/dir1", 0700)
+	dir1, err := os.Open(tmpDir + "/dir1")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer dir1.Close()
+	os.Mkdir(tmpDir+"/dir2", 0700)
+	dir2, err := os.Open(tmpDir + "/dir2")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer dir2.Close()
+	fd, err := os.Create(tmpDir + "/dir1/f1")
+	if err != nil {
+		t.Fatal(err)
+	}
+	fd.Close()
+	err = Renameat(int(dir1.Fd()), "f1", int(dir2.Fd()), "f2")
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = os.Stat(tmpDir + "/dir2/f2")
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Test with absolute path
+	err = Renameat(-1, tmpDir+"/dir2/f2", -1, tmpDir+"/dir2/f1")
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = os.Stat(tmpDir + "/dir2/f1")
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
 func TestFchmodat(t *testing.T) {
 	regular := "TestFchmodat_Regular"
 	f, err := os.OpenFile(tmpDir+"/"+regular, os.O_CREATE|os.O_WRONLY, 0000)
diff --git a/internal/syscallcompat/sys_darwin.go b/internal/syscallcompat/sys_darwin.go
index 358123c..f49e41a 100644
--- a/internal/syscallcompat/sys_darwin.go
+++ b/internal/syscallcompat/sys_darwin.go
@@ -72,10 +72,6 @@ func OpenatUser(dirfd int, path string, flags int, mode uint32, context *fuse.Co
 	return Openat(dirfd, path, flags, mode)
 }
 
-func Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error) {
-	return emulateRenameat(olddirfd, oldpath, newdirfd, newpath)
-}
-
 func Unlinkat(dirfd int, path string, flags int) (err error) {
 	return emulateUnlinkat(dirfd, path, flags)
 }
diff --git a/internal/syscallcompat/sys_linux.go b/internal/syscallcompat/sys_linux.go
index d5dc021..c58f51d 100644
--- a/internal/syscallcompat/sys_linux.go
+++ b/internal/syscallcompat/sys_linux.go
@@ -80,11 +80,6 @@ func OpenatUser(dirfd int, path string, flags int, mode uint32, context *fuse.Co
 	return Openat(dirfd, path, flags, mode)
 }
 
-// Renameat wraps the Renameat syscall.
-func Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error) {
-	return syscall.Renameat(olddirfd, oldpath, newdirfd, newpath)
-}
-
 // Unlinkat syscall.
 func Unlinkat(dirfd int, path string, flags int) (err error) {
 	return unix.Unlinkat(dirfd, path, flags)