syscallcompat: drop Faccessat AT_SYMLINK_NOFOLLOW helper

unix.Faccessat has added support for AT_SYMLINK_NOFOLLOW in July 2018,
https://github.com/golang/sys/commit/bd9dbc187b6e1dacfdd2722a87e83093c2d7bd6e#diff-341484dbbe3180cd7a31ef2ad2d679b6
which means we no longer need our own helper.

Closes https://github.com/rfjakob/gocryptfs/issues/347

4 files changed, 11 insertions, 27 deletions

diff --git a/internal/fusefrontend/fs.go b/internal/fusefrontend/fs.go
index 096e663..decd13f 100644
--- a/internal/fusefrontend/fs.go
+++ b/internal/fusefrontend/fs.go
@@ -626,7 +626,7 @@ func (fs *FS) Access(relPath string, mode uint32, context *fuse.Context) (code f
 	if err != nil {
 		return fuse.ToStatus(err)
 	}
-	err = syscallcompat.Faccessat(dirfd, cName, mode)
+	err = unix.Faccessat(dirfd, cName, mode, unix.AT_SYMLINK_NOFOLLOW)
 	syscall.Close(dirfd)
 	return fuse.ToStatus(err)
 }
diff --git a/internal/fusefrontend/openbackingdir_test.go b/internal/fusefrontend/openbackingdir_test.go
index 82cc74d..9c2358e 100644
--- a/internal/fusefrontend/openbackingdir_test.go
+++ b/internal/fusefrontend/openbackingdir_test.go
@@ -7,7 +7,6 @@ import (
 
 	"golang.org/x/sys/unix"
 
-	"github.com/rfjakob/gocryptfs/internal/syscallcompat"
 	"github.com/rfjakob/gocryptfs/tests/test_helpers"
 )
 
@@ -46,11 +45,11 @@ func TestOpenBackingDir(t *testing.T) {
 		t.Fatal("cName should be .")
 	}
 
-	err = syscallcompat.Faccessat(dirfd, cName, unix.R_OK)
+	err = unix.Faccessat(dirfd, cName, unix.R_OK, unix.AT_SYMLINK_NOFOLLOW)
 	if err != nil {
 		t.Error(err)
 	}
-	err = syscallcompat.Faccessat(dirfd, ".", unix.R_OK)
+	err = unix.Faccessat(dirfd, ".", unix.R_OK, unix.AT_SYMLINK_NOFOLLOW)
 	if err != nil {
 		t.Error(err)
 	}
@@ -63,7 +62,7 @@ func TestOpenBackingDir(t *testing.T) {
 	if cName == "" {
 		t.Fatal("cName should not be empty")
 	}
-	err = syscallcompat.Faccessat(dirfd, cName, unix.R_OK)
+	err = unix.Faccessat(dirfd, cName, unix.R_OK, unix.AT_SYMLINK_NOFOLLOW)
 	if err != nil {
 		t.Error(err)
 	}
@@ -76,7 +75,7 @@ func TestOpenBackingDir(t *testing.T) {
 	if cName == "" {
 		t.Fatal("cName should not be empty")
 	}
-	err = syscallcompat.Faccessat(dirfd, cName, unix.R_OK)
+	err = unix.Faccessat(dirfd, cName, unix.R_OK, unix.AT_SYMLINK_NOFOLLOW)
 	if err != nil {
 		t.Error(err)
 	}
@@ -95,7 +94,7 @@ func TestOpenBackingDir(t *testing.T) {
 	if len(cName) >= 255 {
 		t.Fatalf("cName is too long: %q", cName)
 	}
-	err = syscallcompat.Faccessat(dirfd, cName, unix.R_OK)
+	err = unix.Faccessat(dirfd, cName, unix.R_OK, unix.AT_SYMLINK_NOFOLLOW)
 	if err != nil {
 		t.Error(err)
 	}
@@ -126,11 +125,11 @@ func TestOpenBackingDirPlaintextNames(t *testing.T) {
 	if cName != "." {
 		t.Fatal("cName should be .")
 	}
-	err = syscallcompat.Faccessat(dirfd, cName, unix.R_OK)
+	err = unix.Faccessat(dirfd, cName, unix.R_OK, unix.AT_SYMLINK_NOFOLLOW)
 	if err != nil {
 		t.Error(err)
 	}
-	err = syscallcompat.Faccessat(dirfd, ".", unix.R_OK)
+	err = unix.Faccessat(dirfd, ".", unix.R_OK, unix.AT_SYMLINK_NOFOLLOW)
 	if err != nil {
 		t.Error(err)
 	}
@@ -143,7 +142,7 @@ func TestOpenBackingDirPlaintextNames(t *testing.T) {
 	if cName != "dir1" {
 		t.Fatalf("wrong cName: %q", cName)
 	}
-	err = syscallcompat.Faccessat(dirfd, cName, unix.R_OK)
+	err = unix.Faccessat(dirfd, cName, unix.R_OK, unix.AT_SYMLINK_NOFOLLOW)
 	if err != nil {
 		t.Error(err)
 	}
@@ -156,7 +155,7 @@ func TestOpenBackingDirPlaintextNames(t *testing.T) {
 	if cName != "dir2" {
 		t.Fatalf("wrong cName: %q", cName)
 	}
-	err = syscallcompat.Faccessat(dirfd, cName, unix.R_OK)
+	err = unix.Faccessat(dirfd, cName, unix.R_OK, unix.AT_SYMLINK_NOFOLLOW)
 	if err != nil {
 		t.Error(err)
 	}
diff --git a/internal/fusefrontend_reverse/rfs.go b/internal/fusefrontend_reverse/rfs.go
index 6ee10fc..28b20f8 100644
--- a/internal/fusefrontend_reverse/rfs.go
+++ b/internal/fusefrontend_reverse/rfs.go
@@ -255,7 +255,7 @@ func (rfs *ReverseFS) Access(relPath string, mode uint32, context *fuse.Context)
 	if err != nil {
 		return fuse.ToStatus(err)
 	}
-	err = syscallcompat.Faccessat(dirfd, name, mode)
+	err = unix.Faccessat(dirfd, name, mode, unix.AT_SYMLINK_NOFOLLOW)
 	syscall.Close(dirfd)
 	return fuse.ToStatus(err)
 }
diff --git a/internal/syscallcompat/sys_common.go b/internal/syscallcompat/sys_common.go
index b6bbdff..aedc4da 100644
--- a/internal/syscallcompat/sys_common.go
+++ b/internal/syscallcompat/sys_common.go
@@ -29,21 +29,6 @@ func Readlinkat(dirfd int, path string) (string, error) {
 	}
 }
 
-// Faccessat exists both in Linux and in MacOS 10.10+, but the Linux version
-// DOES NOT support any flags. Emulate AT_SYMLINK_NOFOLLOW like glibc does.
-func Faccessat(dirfd int, path string, mode uint32) error {
-	var st unix.Stat_t
-	err := Fstatat(dirfd, path, &st, unix.AT_SYMLINK_NOFOLLOW)
-	if err != nil {
-		return err
-	}
-	if st.Mode&syscall.S_IFMT == syscall.S_IFLNK {
-		// Pretend that a symlink is always accessible
-		return nil
-	}
-	return unix.Faccessat(dirfd, path, mode, 0)
-}
-
 // Openat wraps the Openat syscall.
 func Openat(dirfd int, path string, flags int, mode uint32) (fd int, err error) {
 	if flags&syscall.O_CREAT != 0 {