syscallcompat: Drop Fstatat emulation on macOS.

6 files changed, 45 insertions, 71 deletions

diff --git a/internal/syscallcompat/emulate.go b/internal/syscallcompat/emulate.go
index 7bed31a..91b592b 100644
--- a/internal/syscallcompat/emulate.go
+++ b/internal/syscallcompat/emulate.go
@@ -4,8 +4,6 @@ import (
 	"path/filepath"
 	"sync"
 	"syscall"
-
-	"golang.org/x/sys/unix"
 )
 
 var chdirMutex sync.Mutex
@@ -29,23 +27,3 @@ func emulateMknodat(dirfd int, path string, mode uint32, dev int) error {
 	}
 	return syscall.Mknod(path, mode, dev)
 }
-
-// emulateFstatat emulates the syscall for platforms that don't have it
-// in the kernel (darwin).
-func emulateFstatat(dirfd int, path string, stat *unix.Stat_t, flags int) (err error) {
-	if !filepath.IsAbs(path) {
-		chdirMutex.Lock()
-		defer chdirMutex.Unlock()
-		cwd, err := syscall.Open(".", syscall.O_RDONLY, 0)
-		if err != nil {
-			return err
-		}
-		defer syscall.Close(cwd)
-		err = syscall.Fchdir(dirfd)
-		if err != nil {
-			return err
-		}
-		defer syscall.Fchdir(cwd)
-	}
-	return unix.Lstat(path, stat)
-}
diff --git a/internal/syscallcompat/emulate_test.go b/internal/syscallcompat/emulate_test.go
index eeffebf..16383f2 100644
--- a/internal/syscallcompat/emulate_test.go
+++ b/internal/syscallcompat/emulate_test.go
@@ -26,38 +26,3 @@ func TestEmulateMknodat(t *testing.T) {
 		t.Fatal(err)
 	}
 }
-
-func TestEmulateFstatat(t *testing.T) {
-	var st unix.Stat_t
-	// stat a normal file (size 3)
-	f, err := os.Create(tmpDir + "/fstatat")
-	if err != nil {
-		t.Fatal(err)
-	}
-	_, err = f.Write([]byte("foo"))
-	if err != nil {
-		t.Fatal(err)
-	}
-	f.Close()
-	err = emulateFstatat(tmpDirFd, "fstatat", &st, unix.AT_SYMLINK_NOFOLLOW)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if st.Size != 3 {
-		t.Errorf("wrong file size: %d", st.Size)
-	}
-	// stat a symlink and check that the size matches the length of the
-	// symlink target. This proves that we have stat'ed the symlink itself.
-	err = os.Symlink(tmpDir+"/fstatat", tmpDir+"/fstatatSymlink")
-	if err != nil {
-		t.Fatal(err)
-	}
-	err = emulateFstatat(tmpDirFd, "fstatatSymlink", &st, unix.AT_SYMLINK_NOFOLLOW)
-	if err != nil {
-		t.Fatal(err)
-	}
-	expectedSize := int64(len(tmpDir + "/fstatat"))
-	if st.Size != expectedSize {
-		t.Errorf("symlink size: expected=%d, got=%d", expectedSize, st.Size)
-	}
-}
diff --git a/internal/syscallcompat/sys_common.go b/internal/syscallcompat/sys_common.go
index 577e2ed..b6bbdff 100644
--- a/internal/syscallcompat/sys_common.go
+++ b/internal/syscallcompat/sys_common.go
@@ -97,6 +97,16 @@ func Mkdirat(dirfd int, path string, mode uint32) (err error) {
 	return unix.Mkdirat(dirfd, path, mode)
 }
 
+// Fstatat syscall.
+func Fstatat(dirfd int, path string, stat *unix.Stat_t, flags int) (err error) {
+	// Why would we ever want to call this without AT_SYMLINK_NOFOLLOW?
+	if flags&unix.AT_SYMLINK_NOFOLLOW == 0 {
+		tlog.Warn.Printf("Fstatat: adding missing AT_SYMLINK_NOFOLLOW flag")
+		flags |= unix.AT_SYMLINK_NOFOLLOW
+	}
+	return unix.Fstatat(dirfd, path, stat, flags)
+}
+
 const XATTR_SIZE_MAX = 65536
 
 // Make the buffer 1kB bigger so we can detect overflows
diff --git a/internal/syscallcompat/sys_common_test.go b/internal/syscallcompat/sys_common_test.go
index e1c7b24..14e1b3f 100644
--- a/internal/syscallcompat/sys_common_test.go
+++ b/internal/syscallcompat/sys_common_test.go
@@ -273,3 +273,38 @@ func TestMkdirat(t *testing.T) {
 		t.Fatalf("mkdirat did not create a directory")
 	}
 }
+
+func TestFstatat(t *testing.T) {
+	var st unix.Stat_t
+	// stat a normal file (size 3)
+	f, err := os.Create(tmpDir + "/fstatat")
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = f.Write([]byte("foo"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	f.Close()
+	err = Fstatat(tmpDirFd, "fstatat", &st, unix.AT_SYMLINK_NOFOLLOW)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if st.Size != 3 {
+		t.Errorf("wrong file size: %d", st.Size)
+	}
+	// stat a symlink and check that the size matches the length of the
+	// symlink target. This proves that we have stat'ed the symlink itself.
+	err = os.Symlink(tmpDir+"/fstatat", tmpDir+"/fstatatSymlink")
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = Fstatat(tmpDirFd, "fstatatSymlink", &st, unix.AT_SYMLINK_NOFOLLOW)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expectedSize := int64(len(tmpDir + "/fstatat"))
+	if st.Size != expectedSize {
+		t.Errorf("symlink size: expected=%d, got=%d", expectedSize, st.Size)
+	}
+}
diff --git a/internal/syscallcompat/sys_darwin.go b/internal/syscallcompat/sys_darwin.go
index 3b27560..b8b82c8 100644
--- a/internal/syscallcompat/sys_darwin.go
+++ b/internal/syscallcompat/sys_darwin.go
@@ -132,10 +132,6 @@ func MkdiratUser(dirfd int, path string, mode uint32, context *fuse.Context) (er
 	return Mkdirat(dirfd, path, mode)
 }
 
-func Fstatat(dirfd int, path string, stat *unix.Stat_t, flags int) (err error) {
-	return emulateFstatat(dirfd, path, stat, flags)
-}
-
 func Getdents(fd int) ([]fuse.DirEntry, error) {
 	return emulateGetdents(fd)
 }
diff --git a/internal/syscallcompat/sys_linux.go b/internal/syscallcompat/sys_linux.go
index 21e07c9..e662001 100644
--- a/internal/syscallcompat/sys_linux.go
+++ b/internal/syscallcompat/sys_linux.go
@@ -198,16 +198,6 @@ func MkdiratUser(dirfd int, path string, mode uint32, context *fuse.Context) (er
 	return Mkdirat(dirfd, path, mode)
 }
 
-// Fstatat syscall.
-func Fstatat(dirfd int, path string, stat *unix.Stat_t, flags int) (err error) {
-	// Why would we ever want to call this without AT_SYMLINK_NOFOLLOW?
-	if flags&unix.AT_SYMLINK_NOFOLLOW == 0 {
-		tlog.Warn.Printf("Fstatat: adding missing AT_SYMLINK_NOFOLLOW flag")
-		flags |= unix.AT_SYMLINK_NOFOLLOW
-	}
-	return unix.Fstatat(dirfd, path, stat, flags)
-}
-
 // Getdents syscall.
 func Getdents(fd int) ([]fuse.DirEntry, error) {
 	return getdents(fd)