darwin: use O_NOFOLLOW for xattr opens

Running the tests we have lots of these:

Openat: O_NOFOLLOW missing: flags = 0x4
-wpanic turns this warning into a panic: Openat: O_NOFOLLOW missing: flags = 0x4
panic: -wpanic turns this warning into a panic: Openat: O_NOFOLLOW missing: flags = 0x4

goroutine 114 [running]:
log.(*Logger).Panic(0x14000118280, {0x14000313ca8, 0x1, 0x1})
	log/log.go:224 +0x90
github.com/rfjakob/gocryptfs/v2/internal/tlog.(*toggledLogger).Printf(0x14000076780, {0x1009dc2e8, 0x27}, {0x14000313d18, 0x1, 0x1})
	github.com/rfjakob/gocryptfs/v2/internal/tlog/log.go:78 +0x168
github.com/rfjakob/gocryptfs/v2/internal/syscallcompat.Openat(0x9, {0x1009d0747, 0x1}, 0x4, 0x0)
	github.com/rfjakob/gocryptfs/v2/internal/syscallcompat/sys_common.go:59 +0xf0
github.com/rfjakob/gocryptfs/v2/internal/fusefrontend.(*Node).getXAttr(0x14000142000, {0x1400001c140, 0x3a})
	github.com/rfjakob/gocryptfs/v2/internal/fusefrontend/node_xattr_darwin.go:30 +0x8c
github.com/rfjakob/gocryptfs/v2/internal/fusefrontend.(*Node).Getxattr(0x14000142000, {0x100a7eba0, 0x1400000c2e8}, {0x14000016348, 0x14}, {0x14000326000, 0x20, 0x4000})
	github.com/rfjakob/gocryptfs/v2/internal/fusefrontend/node_xattr.go:65 +0x1ac
github.com/hanwen/go-fuse/v2/fs.(*rawBridge).GetXAttr(0x1400008e140, 0x140001901e0, 0x140001133c0, {0x14000016348, 0x14}, {0x14000326000, 0x20, 0x4000})
	github.com/hanwen/go-fuse/v2@v2.1.1-0.20210825171523-3ab5d95a30ae/fs/bridge.go:685 +0x114
github.com/hanwen/go-fuse/v2/fuse.doGetXAttr(0x14000144000, 0x14000113200)
	github.com/hanwen/go-fuse/v2@v2.1.1-0.20210825171523-3ab5d95a30ae/fuse/opcode.go:270 +0x224
github.com/hanwen/go-fuse/v2/fuse.(*Server).handleRequest(0x14000144000, 0x14000113200)
	github.com/hanwen/go-fuse/v2@v2.1.1-0.20210825171523-3ab5d95a30ae/fuse/server.go:499 +0x214
created by github.com/hanwen/go-fuse/v2/fuse.(*Server).loop
	github.com/hanwen/go-fuse/v2@v2.1.1-0.20210825171523-3ab5d95a30ae/fuse/server.go:470 +0xac

https://github.com/rfjakob/gocryptfs/issues/625

2 files changed, 7 insertions, 7 deletions

diff --git a/internal/fusefrontend/node_xattr_darwin.go b/internal/fusefrontend/node_xattr_darwin.go
index 8c8a153..a539847 100644
--- a/internal/fusefrontend/node_xattr_darwin.go
+++ b/internal/fusefrontend/node_xattr_darwin.go
@@ -27,7 +27,7 @@ func (n *Node) getXAttr(cAttr string) (out []byte, errno syscall.Errno) {
 	defer syscall.Close(dirfd)
 
 	// O_NONBLOCK to not block on FIFOs.
-	fd, err := syscallcompat.Openat(dirfd, cName, syscall.O_RDONLY|syscall.O_NONBLOCK, 0)
+	fd, err := syscallcompat.Openat(dirfd, cName, syscall.O_RDONLY|syscall.O_NONBLOCK|syscall.O_NOFOLLOW, 0)
 	if err != nil {
 		return nil, fs.ToErrno(err)
 	}
@@ -49,10 +49,10 @@ func (n *Node) setXAttr(context *fuse.Context, cAttr string, cData []byte, flags
 	defer syscall.Close(dirfd)
 
 	// O_NONBLOCK to not block on FIFOs.
-	fd, err := syscallcompat.Openat(dirfd, cName, syscall.O_WRONLY|syscall.O_NONBLOCK, 0)
+	fd, err := syscallcompat.Openat(dirfd, cName, syscall.O_WRONLY|syscall.O_NONBLOCK|syscall.O_NOFOLLOW, 0)
 	// Directories cannot be opened read-write. Retry.
 	if err == syscall.EISDIR {
-		fd, err = syscallcompat.Openat(dirfd, cName, syscall.O_RDONLY|syscall.O_DIRECTORY|syscall.O_NONBLOCK, 0)
+		fd, err = syscallcompat.Openat(dirfd, cName, syscall.O_RDONLY|syscall.O_DIRECTORY|syscall.O_NONBLOCK|syscall.O_NOFOLLOW, 0)
 	}
 	if err != nil {
 		fs.ToErrno(err)
@@ -71,10 +71,10 @@ func (n *Node) removeXAttr(cAttr string) (errno syscall.Errno) {
 	defer syscall.Close(dirfd)
 
 	// O_NONBLOCK to not block on FIFOs.
-	fd, err := syscallcompat.Openat(dirfd, cName, syscall.O_WRONLY|syscall.O_NONBLOCK, 0)
+	fd, err := syscallcompat.Openat(dirfd, cName, syscall.O_WRONLY|syscall.O_NONBLOCK|syscall.O_NOFOLLOW, 0)
 	// Directories cannot be opened read-write. Retry.
 	if err == syscall.EISDIR {
-		fd, err = syscallcompat.Openat(dirfd, cName, syscall.O_RDONLY|syscall.O_DIRECTORY|syscall.O_NONBLOCK, 0)
+		fd, err = syscallcompat.Openat(dirfd, cName, syscall.O_RDONLY|syscall.O_DIRECTORY|syscall.O_NONBLOCK|syscall.O_NOFOLLOW, 0)
 	}
 	if err != nil {
 		return fs.ToErrno(err)
@@ -93,7 +93,7 @@ func (n *Node) listXAttr() (out []string, errno syscall.Errno) {
 	defer syscall.Close(dirfd)
 
 	// O_NONBLOCK to not block on FIFOs.
-	fd, err := syscallcompat.Openat(dirfd, cName, syscall.O_RDONLY|syscall.O_NONBLOCK, 0)
+	fd, err := syscallcompat.Openat(dirfd, cName, syscall.O_RDONLY|syscall.O_NONBLOCK|syscall.O_NOFOLLOW, 0)
 	if err != nil {
 		return nil, fs.ToErrno(err)
 	}
diff --git a/internal/syscallcompat/sys_darwin.go b/internal/syscallcompat/sys_darwin.go
index 075563f..de795a4 100644
--- a/internal/syscallcompat/sys_darwin.go
+++ b/internal/syscallcompat/sys_darwin.go
@@ -14,7 +14,7 @@ import (
 )
 
 const (
-	// O_DIRECT means oncached I/O on Linux. No direct equivalent on MacOS and defined
+	// O_DIRECT means uncached I/O on Linux. No direct equivalent on MacOS and defined
 	// to zero there.
 	O_DIRECT = 0