kern: Add initial vnode initialization

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

2 files changed, 191 insertions, 0 deletions

diff --git a/sys/inc/os/vnode.h b/sys/inc/os/vnode.h
new file mode 100644
index 0000000..4ba5d8e
--- /dev/null
+++ b/sys/inc/os/vnode.h
@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2025 Ian Marco Moffett and the Osmora Team.
+ * 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 Hyra 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_
+
+#include <sys/types.h>
+
+struct vnode;
+
+/*
+ * Valid vnode types
+ */
+typedef enum {
+    VREG,
+    VDIR,
+    VCHR,
+    VBLK
+} vtype_t;
+
+/*
+ * Arguments for the read() operation
+ */
+struct vop_read_args {
+    void *buffer;
+    off_t offset;
+    size_t len;
+};
+
+/*
+ * Operations that can be performed on a vnode
+ */
+struct vops {
+    ssize_t(*read)(struct vop_read_args *args);
+    ssize_t(*write)(struct vop_read_args *args);
+    void(*reclaim)(struct vnode *vp);
+};
+
+/*
+ * A virtual file node is an abstract repre
+ *
+ * @type: Vnode type
+ * @vops: Operations associated with vnode
+ * @ref:  Reference counter
+ * @data: Filesystem specific data
+ */
+struct vnode {
+    vtype_t type;
+    struct vops vops;
+    int ref;
+    void *data;
+};
+
+/*
+ * Initialize a vnode by type
+ *
+ * @vp_res: Vnode pointer result
+ * @vtype: Vnode type to initialize
+ *
+ * Returns zero on success
+ */
+int vnode_init(struct vnode **vp_res, vtype_t type);
+
+/*
+ * Release a vnode from memory
+ *
+ * @vp: Vnode to release from memory
+ *
+ * Returns the reference count if not released, zero
+ * on successful release.
+ */
+int vnode_release(struct vnode *vp);
+
+#endif  /* !_OS_VNODE_H_ */
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
new file mode 100644
index 0000000..5b53c0a
--- /dev/null
+++ b/sys/kern/vfs_subr.c
@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2025 Ian Marco Moffett and the Osmora Team.
+ * 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 Hyra 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.
+ */
+
+#include <sys/errno.h>
+#include <os/vnode.h>
+#include <vm/kalloc.h>
+#include <lib/string.h>
+
+int
+vnode_init(struct vnode **vp_res, vtype_t type)
+{
+    struct vnode *vp;
+
+    if (vp_res == NULL) {
+        return -EINVAL;
+    }
+
+    switch (type) {
+    case VREG:
+    case VDIR:
+    case VCHR:
+    case VBLK:
+        break;
+    default:
+        return -EINVAL;
+    }
+
+    vp = kalloc(sizeof(*vp));
+    if (vp == NULL) {
+        return -ENOMEM;
+    }
+
+    memset(vp, 0, sizeof(*vp));
+    vp->ref = 1;
+    vp->type = type;
+    *vp_res = vp;
+    return 0;
+}
+
+int
+vnode_release(struct vnode *vp)
+{
+    struct vops *vops;
+
+    if (vp == NULL) {
+        return -EINVAL;
+    }
+
+    vops = &vp->vops;
+
+    /*
+     * If there are zero outstanding references to this
+     * vnode, release it from memory.
+     */
+    if ((vp->ref--) > 0) {
+        return vp->ref;
+    }
+
+    if (vops->reclaim != NULL) {
+        vops->reclaim(vp);
+    }
+
+    kfree(vp);
+    return 0;
+}