fusefronted: move Create() and Open() to new file

And deduplicate the code a little.

1 files changed, 108 insertions, 0 deletions

diff --git a/internal/fusefrontend/node_open_create.go b/internal/fusefrontend/node_open_create.go
new file mode 100644
index 0000000..8b31932
--- /dev/null
+++ b/internal/fusefrontend/node_open_create.go
@@ -0,0 +1,108 @@
+package fusefrontend
+
+import (
+	"context"
+	"syscall"
+
+	"github.com/hanwen/go-fuse/v2/fs"
+	"github.com/hanwen/go-fuse/v2/fuse"
+
+	"github.com/rfjakob/gocryptfs/internal/nametransform"
+	"github.com/rfjakob/gocryptfs/internal/syscallcompat"
+	"github.com/rfjakob/gocryptfs/internal/tlog"
+)
+
+// Open - FUSE call. Open already-existing file.
+//
+// Symlink-safe through Openat().
+func (n *Node) Open(ctx context.Context, flags uint32) (fh fs.FileHandle, fuseFlags uint32, errno syscall.Errno) {
+	dirfd, cName, errno := n.prepareAtSyscall("")
+	if errno != 0 {
+		return
+	}
+	defer syscall.Close(dirfd)
+
+	rn := n.rootNode()
+	newFlags := rn.mangleOpenFlags(flags)
+	// Taking this lock makes sure we don't race openWriteOnlyFile()
+	rn.openWriteOnlyLock.RLock()
+	defer rn.openWriteOnlyLock.RUnlock()
+
+	if rn.args.KernelCache {
+		fuseFlags = fuse.FOPEN_KEEP_CACHE
+	}
+
+	// Open backing file
+	fd, err := syscallcompat.Openat(dirfd, cName, newFlags, 0)
+	// Handle a few specific errors
+	if err != nil {
+		if err == syscall.EMFILE {
+			var lim syscall.Rlimit
+			syscall.Getrlimit(syscall.RLIMIT_NOFILE, &lim)
+			tlog.Warn.Printf("Open %q: too many open files. Current \"ulimit -n\": %d", cName, lim.Cur)
+		}
+		if err == syscall.EACCES && (int(flags)&syscall.O_ACCMODE) == syscall.O_WRONLY {
+			fd, err = rn.openWriteOnlyFile(dirfd, cName, newFlags)
+		}
+	}
+	// Could not handle the error? Bail out
+	if err != nil {
+		errno = fs.ToErrno(err)
+		return
+	}
+	fh, _, errno = NewFile(fd, cName, rn)
+	return fh, fuseFlags, errno
+}
+
+// Create - FUSE call. Creates a new file.
+//
+// Symlink-safe through the use of Openat().
+func (n *Node) Create(ctx context.Context, name string, flags uint32, mode uint32, out *fuse.EntryOut) (inode *fs.Inode, fh fs.FileHandle, fuseFlags uint32, errno syscall.Errno) {
+	dirfd, cName, errno := n.prepareAtSyscall(name)
+	if errno != 0 {
+		return
+	}
+	defer syscall.Close(dirfd)
+
+	var err error
+	fd := -1
+	// Make sure context is nil if we don't want to preserve the owner
+	rn := n.rootNode()
+	if !rn.args.PreserveOwner {
+		ctx = nil
+	}
+	newFlags := rn.mangleOpenFlags(flags)
+	// Handle long file name
+	ctx2 := toFuseCtx(ctx)
+	if !rn.args.PlaintextNames && nametransform.IsLongContent(cName) {
+		// Create ".name"
+		err = rn.nameTransform.WriteLongNameAt(dirfd, cName, name)
+		if err != nil {
+			return nil, nil, 0, fs.ToErrno(err)
+		}
+		// Create content
+		fd, err = syscallcompat.OpenatUser(dirfd, cName, newFlags|syscall.O_CREAT|syscall.O_EXCL, mode, ctx2)
+		if err != nil {
+			nametransform.DeleteLongNameAt(dirfd, cName)
+		}
+	} else {
+		// Create content, normal (short) file name
+		fd, err = syscallcompat.OpenatUser(dirfd, cName, newFlags|syscall.O_CREAT|syscall.O_EXCL, mode, ctx2)
+	}
+	if err != nil {
+		// xfstests generic/488 triggers this
+		if err == syscall.EMFILE {
+			var lim syscall.Rlimit
+			syscall.Getrlimit(syscall.RLIMIT_NOFILE, &lim)
+			tlog.Warn.Printf("Create %q: too many open files. Current \"ulimit -n\": %d", cName, lim.Cur)
+		}
+		return nil, nil, 0, fs.ToErrno(err)
+	}
+
+	fh, st, errno := NewFile(fd, cName, rn)
+	if errno != 0 {
+		return
+	}
+	inode = n.newChild(ctx, st, out)
+	return inode, fh, fuseFlags, errno
+}