kern: vfs: Add initial vnode definitions

A vnode is simply an object used when referencing filesystem objects.
This marks the start of development for the L5 Virtual File System

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 93 insertions, 0 deletions

diff --git a/src/sys/include/os/vnode.h b/src/sys/include/os/vnode.h
new file mode 100644
index 0000000..9549730
--- /dev/null
+++ b/src/sys/include/os/vnode.h
@@ -0,0 +1,93 @@
+/*
+ * Copyright (c) 2025 Ian Marco Moffett and L5 engineers
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the project nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _OS_VNODE_H_
+#define _OS_VNODE_H_ 1
+
+#include <sys/types.h>
+
+/* Forward declarations */
+struct vnode;
+struct vop;
+
+/*
+ * Valid vnode types
+ *
+ * @VTYPE_NONE: Vnode is yet to be assigned a type
+ * @VTYPE_FILE: Vnode references a file
+ * @VTYPE_DIR:  Vnode references a directory
+ * @__N_VTYPE:  Number of valid nodes on the system
+ */
+typedef enum {
+    VTYPE_NONE,
+    VTYPE_FILE,
+    VTYPE_DIR,
+    __N_VTYPE
+} vtype_t;
+
+/*
+ * Represents the arguments used in a vnode lookup
+ * operation
+ *
+ * @name: Path componenet to look up
+ * @dirvp: Current directory
+ * @vpp: Resulting vnode pointer is written here
+ */
+struct vop_lookup_args {
+    const char *name;
+    struct vnode *dirvp;
+    struct vnode **vpp;
+};
+
+/*
+ * Represents operations that can be performed on
+ * a specific vnode. These are implemented as callbacks
+ */
+struct vop {
+    int(*lookup)(struct vop_lookup_args *args);
+};
+
+/*
+ * Abstract representation of a referenced filesystem object
+ * such as a file, directory, network file object,
+ * etc.
+ *
+ * [D]: Set up by driver
+ * [V]  Set up by VFS
+ * [D/V]: Both D and V
+ *
+ * @vtype: Vnode type  [D/V]
+ * @vops:  Vnode operations hooks [D]
+ */
+struct vnode {
+    vtype_t vtype;
+    struct vop *vops;
+};
+
+#endif  /* !_OS_VNODE_H_ */