kern: vfs: Add initial vfsops, and mount code

This commit introduces the groundwork for mountpoints, filesystems and
the VFS as a whole. OMAR is now initialized as its own filesystem by the
VFS

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

2 files changed, 194 insertions, 0 deletions

diff --git a/src/sys/include/os/vfs.h b/src/sys/include/os/vfs.h
new file mode 100644
index 0000000..ec7eb77
--- /dev/null
+++ b/src/sys/include/os/vfs.h
@@ -0,0 +1,57 @@
+/*
+ * 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_VFS_H_
+#define _OS_VFS_H_ 1
+
+#include <sys/types.h>
+#include <sys/mount.h>
+
+/*
+ * Initialize the virtual filesystem
+ * layer
+ *
+ * Returns zero on success, otherwise a less
+ * than zero value on failure.
+ */
+int vfs_init(void);
+
+/*
+ * Get a VFS file table entry by index.
+ *
+ * @index: Index to desired entry
+ * @resp: Result pointer is written here
+ *
+ * Returns zero on success and the entry being
+ * found, otherwise a less than zero failure if
+ * the entry has not been found.
+ */
+int vfs_by_index(uint16_t index, struct fs_info **resp);
+
+#endif  /* !_OS_VFS_H_ */
diff --git a/src/sys/include/sys/mount.h b/src/sys/include/sys/mount.h
new file mode 100644
index 0000000..c2beb8d
--- /dev/null
+++ b/src/sys/include/sys/mount.h
@@ -0,0 +1,137 @@
+/*
+ * 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 _SYS_MOUNT_H_
+#define _SYS_MOUNT_H_
+
+#include <sys/queue.h>
+#include <sys/types.h>
+#include <os/vnode.h>
+
+#if defined(_KERNEL)
+
+/*
+ * Number of bytes allowed in a filesystem
+ * name including the null termination
+ */
+#define FSNAME_MAX 16
+
+/*
+ * Mount filesystem string names
+ */
+#define MOUNT_INITRD "initrd"   /* Initial ramdisk */
+
+/* Forward declarations */
+struct vfsops;
+struct mount;
+
+/* Filesystem vfsops */
+extern struct vfsops g_omar_vfsops;
+
+/*
+ * Represents a mountpoint
+ */
+struct mount {
+    struct vnode *vp;
+    const char *name;
+    TAILQ_ENTRY(mount) link;
+    TAILQ_HEAD(, mount) buckets;
+};
+
+/*
+ * Represents a list of mountpoints
+ *
+ * @i: Initialized (set if initialized)
+ */
+struct mountlist {
+    uint8_t i : 1;
+    TAILQ_HEAD(, mount) list;
+};
+/*
+ * Arguments for mount()
+ *
+ * @source: Specifies the source filesystem to mount
+ * @target: Specifies the location to mount source
+ * @fstype: File system type
+ * @data: Filesystem specific data
+ */
+struct mount_args {
+    const char *source;
+    const char *target;
+    const char *fstype;
+    const void *data;
+};
+
+/*
+ * Represents information about a filesystem
+ *
+ * @name: Filesystem type name
+ * @vfsops: VFS operations vector
+ * @refcount: Mount count of this type
+ */
+struct fs_info {
+    char name[FSNAME_MAX];
+    const struct vfsops *vfsops;
+    int refcount;
+};
+
+/*
+ * VFS operations vector
+ *
+ * @init: Initialize the filesystem
+ * @mount: Mount a filesystem
+ */
+struct vfsops {
+    int(*init)(struct fs_info *fip);
+    int(*mount)(struct fs_info *fip, struct mount_args *margs);
+};
+
+/*
+ * Mount a specific filesystem
+ *
+ * @margs: Mount arguments
+ * @flags: Mount flags
+ *
+ * Returns zero on success, otherwise a less than zero
+ * failure upon failure.
+ */
+int mount(struct mount_args *margs, uint32_t flags);
+
+/*
+ * Initialize a mountpoint to a known state
+ *
+ * @mp: Pointer to mountlist [if NULL, use root]
+ *
+ * Returns zero on success, otherwise a less than
+ * zero value on failure.
+ */
+int mountlist_init(struct mountlist *mlp);
+
+#endif  /* !_KERNEL */
+#endif  /* !_SYS_MOUNT_H_ */