kernel: Add initramfs and initial VFS code

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

9 files changed, 781 insertions, 0 deletions

diff --git a/sys/fs/initramfs.c b/sys/fs/initramfs.c
new file mode 100644
index 0000000..4c47da8
--- /dev/null
+++ b/sys/fs/initramfs.c
@@ -0,0 +1,263 @@
+/*
+ * Copyright (c) 2023-2024 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/mount.h>
+#include <sys/types.h>
+#include <sys/cdefs.h>
+#include <sys/errno.h>
+#include <sys/limine.h>
+#include <sys/panic.h>
+#include <sys/vnode.h>
+#include <fs/initramfs.h>
+#include <vm/dynalloc.h>
+#include <string.h>
+
+#define CPIO_TRAILER "TRAILER!!!"
+
+/*
+ * File or directory.
+ */
+struct initramfs_node {
+    const char *path;       /* Path */
+    void *data;             /* File data */
+    size_t size;            /* File size */
+    mode_t mode;            /* Perms and type */
+};
+
+/*
+ * ODC CPIO header
+ */
+struct cpio_hdr {
+    char c_magic[6];
+    char c_dev[6];
+    char c_ino[6];
+    char c_mode[6];
+    char c_uid[6];
+    char c_gid[6];
+    char c_nlink[6];
+    char c_rdev[6];
+    char c_mtime[11];
+    char c_namesize[6];
+    char c_filesize[11];
+};
+
+static volatile struct limine_module_request mod_req = {
+    .id = LIMINE_MODULE_REQUEST,
+    .revision = 0
+};
+
+static const char *initramfs = NULL;
+static uint64_t initramfs_size;
+
+/*
+ * Fetch a module from the bootloader.
+ * This is used to fetch the ramfs image.
+ */
+static char *
+get_module(const char *path, uint64_t *size) {
+    for (uint64_t i = 0; i < mod_req.response->module_count; ++i) {
+        if (strcmp(mod_req.response->modules[i]->path, path) == 0) {
+            *size = mod_req.response->modules[i]->size;
+            return mod_req.response->modules[i]->address;
+        }
+    }
+
+    return NULL;
+}
+
+/*
+ * Convert octal to base 10
+ */
+static uint32_t
+oct2dec(const char *in, size_t sz)
+{
+    size_t val = 0;
+
+    for (size_t i = 0; i < sz; ++i) {
+        val = val * 8 + (in[i] - '0');
+    }
+
+    return val;
+}
+
+/*
+ * Get a file from initramfs
+ *
+ * @path: Path of file to get.
+ * @res: Pointer to new resulting node.
+ */
+static int
+initramfs_get_file(const char *path, struct initramfs_node *res)
+{
+    const struct cpio_hdr *hdr;
+    struct initramfs_node node;
+    uintptr_t addr;
+    size_t namesize, filesize;
+    mode_t mode;
+
+    addr = (uintptr_t)initramfs;
+    for (;;) {
+        hdr = (void *)addr;
+        namesize = oct2dec(hdr->c_namesize, sizeof(hdr->c_namesize));
+        filesize = oct2dec(hdr->c_filesize, sizeof(hdr->c_filesize));
+        mode = oct2dec(hdr->c_mode, sizeof(hdr->c_mode));
+
+        /* Make sure the magic is correct */
+        if (strncmp(hdr->c_magic, "070707", 6) != 0) {
+            return -EINVAL;
+        }
+
+        addr += sizeof(struct cpio_hdr);
+        node.path = (const char *)addr;
+
+        /* Is this the requested file? */
+        if (strcmp(node.path, path) == 0) {
+            node.data = (void *)(addr + namesize);
+            node.size = filesize;
+            node.mode = mode;
+            *res = node;
+            return 0;
+        }
+
+        /* Get next header and see if we are at the end */
+        addr += (namesize + filesize);
+        if (strcmp(node.path, CPIO_TRAILER) == 0) {
+            break;
+        }
+    }
+
+    return -ENOENT;
+}
+
+static int
+initramfs_lookup(struct vop_lookup_args *args)
+{
+    int status, vtype;
+    struct initramfs_node *n;
+    struct vnode *vp;
+    const char *path = args->name;
+
+    if (*path == '/') {
+        ++path;
+    }
+
+    n = dynalloc(sizeof(*n));
+    if (n == NULL) {
+        return -ENOMEM;
+    }
+
+    /* Now does this file exist? */
+    if ((status = initramfs_get_file(path, n)) != 0) {
+        dynfree(n);
+        return status;
+    }
+
+    vtype = ISSET(n->mode, 0040000) ? VDIR : VREG;
+
+    /* Try to create a new vnode */
+    if ((status = vfs_alloc_vnode(&vp, vtype)) != 0) {
+        dynfree(n);
+        return status;
+    }
+
+    vp->data = n;
+    vp->vops = &g_initramfs_vops;
+    *args->vpp = vp;
+    return 0;
+}
+
+static int
+initramfs_read(struct vnode *vp, struct sio_txn *sio)
+{
+    struct initramfs_node *n = vp->data;
+    uint8_t *src, *dest;
+    uint32_t count = 0;
+
+    /* Ensure pointers are valid */
+    if (n == NULL)
+        return -EIO;
+    if (sio->buf == NULL)
+        return -EIO;
+
+    src = n->data;
+    dest = sio->buf;
+
+    /* Copy the file data */
+    for (size_t i = 0; i < sio->len; ++i) {
+        if ((sio->offset + i) >= n->size) {
+            break;
+        }
+        dest[i] = src[sio->offset + i];
+        ++count;
+    }
+
+    return count;
+}
+
+static int
+initramfs_reclaim(struct vnode *vp)
+{
+    if (vp->data != NULL) {
+        dynfree(vp->data);
+    }
+
+    return 0;
+}
+
+static int
+initramfs_init(struct fs_info *fip)
+{
+    struct mount *mp;
+    int status;
+
+    initramfs = get_module("/boot/ramfs.cpio", &initramfs_size);
+    if (initramfs == NULL) {
+        panic("Failed to open initramfs cpio image\n");
+    }
+
+    status = vfs_alloc_vnode(&g_root_vnode, VDIR);
+    if (__unlikely(status != 0)) {
+        panic("Failed to create root vnode for ramfs\n");
+    }
+
+    g_root_vnode->vops = &g_initramfs_vops;
+    mp = vfs_alloc_mount(g_root_vnode, fip);
+    TAILQ_INSERT_TAIL(&g_mountlist, mp, mnt_list);
+    return 0;
+}
+
+const struct vops g_initramfs_vops = {
+    .lookup = initramfs_lookup,
+    .read = initramfs_read,
+    .reclaim = initramfs_reclaim
+};
+
+const struct vfsops g_initramfs_vfsops = {
+    .init = initramfs_init
+};
diff --git a/sys/include/fs/initramfs.h b/sys/include/fs/initramfs.h
new file mode 100644
index 0000000..897079c
--- /dev/null
+++ b/sys/include/fs/initramfs.h
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2023-2024 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 _INITRAMFS_H_
+#define _INITRAMFS_H_
+
+#include <sys/vnode.h>
+
+extern const struct vops g_initramfs_vops;
+
+#endif  /* _INITRAMFS_H_ */
diff --git a/sys/include/sys/mount.h b/sys/include/sys/mount.h
new file mode 100644
index 0000000..e46cda9
--- /dev/null
+++ b/sys/include/sys/mount.h
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2023-2024 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 _SYS_MOUNT_H_
+#define _SYS_MOUNT_H_
+
+#include <sys/types.h>
+#include <sys/queue.h>
+#include <sys/namei.h>
+#include <sys/vnode.h>
+#include <sys/spinlock.h>
+
+#if defined(_KERNEL)
+
+#define FS_NAME_MAX 16  /* Length of fs name including nul */
+
+/*
+ * Filesystem types.
+ */
+#define MOUNT_RAMFS "initramfs"
+
+struct vfsops;
+struct mount;
+
+/* Mount list */
+typedef TAILQ_HEAD(, mount) mountlist_t;
+extern mountlist_t g_mountlist;
+
+/* Filesystem operations */
+extern const struct vfsops g_initramfs_vfsops;
+
+struct mount {
+    struct spinlock lock;
+    struct vnode *vp;
+    const struct vfsops *mnt_ops;
+    void *data;
+    TAILQ_ENTRY(mount) mnt_list;
+};
+
+struct fs_info {
+    char name[FS_NAME_MAX];         /* FS Type name */
+    const struct vfsops *vfsops;    /* Operations vector */
+    int flags;                      /* Flags for this filesystem */
+    int refcount;                   /* Mount count of this type */
+};
+
+struct vfsops {
+    int(*init)(struct fs_info *fip);
+    int(*mount)(struct mount *mp, const char *path, void *data,
+        struct nameidata *ndp);
+};
+
+void vfs_init(void);
+struct mount *vfs_alloc_mount(struct vnode *vp, struct fs_info *fip);
+struct fs_info *vfs_byname(const char *name);
+
+#endif  /* _KERNEL */
+#endif  /* _SYS_MOUNT_H_ */
diff --git a/sys/include/sys/namei.h b/sys/include/sys/namei.h
new file mode 100644
index 0000000..bd3c0db
--- /dev/null
+++ b/sys/include/sys/namei.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2023-2024 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 _SYS_NAMEI_H_
+#define _SYS_NAMEI_H_
+
+#include <sys/types.h>
+#include <sys/vnode.h>
+
+struct nameidata {
+    const char *path;   /* Pathname */
+    uint32_t flags;
+    struct vnode *vp;   /* Vnode result */
+};
+
+int namei(struct nameidata *ndp);
+
+#endif  /* !_SYS_NAMEI_H_ */
diff --git a/sys/include/sys/vnode.h b/sys/include/sys/vnode.h
new file mode 100644
index 0000000..1caf2cb
--- /dev/null
+++ b/sys/include/sys/vnode.h
@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2023-2024 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 _SYS_VNODE_H_
+#define _SYS_VNODE_H_
+
+#include <sys/sio.h>
+
+#if defined(_KERNEL)
+
+struct vops;
+
+struct vnode {
+    int type;
+    int flags;
+    void *data;
+    const struct vops *vops;
+};
+
+/* Vnode type flags */
+#define VNON    0x00    /* Uninitialized */
+#define VREG    0x01    /* Regular file */
+#define VDIR    0x02    /* Directory */
+#define VCHR    0x03    /* Character device */
+#define VBLK    0x04    /* Block device */
+
+struct vop_lookup_args {
+    const char *name;       /* Current path component */
+    struct vnode *dirvp;    /* Directory vnode */
+    struct vnode **vpp;     /* Result vnode */
+};
+
+struct vops {
+    int(*lookup)(struct vop_lookup_args *args);
+    int(*read)(struct vnode *vp, struct sio_txn *sio);
+    int(*reclaim)(struct vnode *vp);
+};
+
+extern struct vnode *g_root_vnode;
+
+int vfs_alloc_vnode(struct vnode **res, int type);
+int vfs_release_vnode(struct vnode *vp);
+
+int vfs_vop_lookup(struct vnode *vp, struct vop_lookup_args *args);
+int vfs_vop_read(struct vnode *vp, struct sio_txn *sio);
+
+#endif  /* _KERNEL */
+#endif  /* !_SYS_VNODE_H_ */
diff --git a/sys/kern/init_main.c b/sys/kern/init_main.c
index 6018dfe..09b8d2d 100644
--- a/sys/kern/init_main.c
+++ b/sys/kern/init_main.c
@@ -30,6 +30,7 @@
 #include <sys/reboot.h>
 #include <sys/syslog.h>
 #include <sys/sched.h>
+#include <sys/mount.h>
 #include <dev/cons/cons.h>
 #include <dev/acpi/acpi.h>
 #include <machine/cpu.h>
@@ -52,6 +53,9 @@ main(void)
     /* Startup the BSP */
     cpu_startup(&g_bsp_ci);
 
+    /* Init the virtual file system */
+    vfs_init();
+
     /* Start scheduler and bootstrap APs */
     sched_init();
     mp_bootstrap_aps(&g_bsp_ci);
diff --git a/sys/kern/vfs_init.c b/sys/kern/vfs_init.c
new file mode 100644
index 0000000..aafbc00
--- /dev/null
+++ b/sys/kern/vfs_init.c
@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2023-2024 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/param.h>
+#include <sys/mount.h>
+#include <sys/vnode.h>
+#include <sys/panic.h>
+#include <string.h>
+
+struct vnode *g_root_vnode = NULL;
+static struct fs_info fs_list[] = {
+    {MOUNT_RAMFS, &g_initramfs_vfsops, 0, 0},
+};
+
+void
+vfs_init(void)
+{
+    struct fs_info *fs;
+    const struct vfsops *vfsops;
+
+    TAILQ_INIT(&g_mountlist);
+
+    for (size_t i= 0; i < NELEM(fs_list); ++i) {
+        fs = &fs_list[i];
+        vfsops = fs->vfsops;
+
+        /* Try to initialize the filesystem */
+        if (vfsops->init != NULL) {
+            vfsops->init(fs);
+        }
+    }
+}
+
+struct fs_info *
+vfs_byname(const char *name)
+{
+    for (int i = 0; i < NELEM(fs_list); ++i) {
+        if (strcmp(fs_list[i].name, name) == 0) {
+            return &fs_list[i];
+        }
+    }
+
+    return NULL;
+}
diff --git a/sys/kern/vfs_lookup.c b/sys/kern/vfs_lookup.c
new file mode 100644
index 0000000..83924c6
--- /dev/null
+++ b/sys/kern/vfs_lookup.c
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2023-2024 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/namei.h>
+#include <sys/vnode.h>
+#include <sys/errno.h>
+#include <vm/dynalloc.h>
+#include <string.h>
+
+/*
+ * Convert a path to a vnode.
+ *
+ * @ndp: Nameidata containing the path and resulting
+ *       vnode.
+ *
+ * TODO: Add support for lookups with individual
+ *       path components
+ */
+int
+namei(struct nameidata *ndp)
+{
+    struct vnode *vp;
+    struct vop_lookup_args lookup_args;
+    const char *path = ndp->path;
+    int status;
+
+    if (path == NULL) {
+        return -EINVAL;
+    }
+
+    /* Path must start with "/" */
+    if (*path != '/') {
+        return -EINVAL;
+    }
+
+    /* Just return the root vnode if we can */
+    if (strcmp(path, "/") == 0) {
+        ndp->vp = g_root_vnode;
+        return 0;
+    }
+
+    /*
+     * Some filesystems (like initramfs) may only understand
+     * full paths, so try passing it through.
+     */
+    lookup_args.name = path;
+    lookup_args.dirvp = g_root_vnode;
+    lookup_args.vpp = &vp;
+    status = vfs_vop_lookup(lookup_args.dirvp, &lookup_args);
+
+    if (status != 0) {
+        return status;
+    }
+
+    ndp->vp = vp;
+    return 0;
+}
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
new file mode 100644
index 0000000..04d64e3
--- /dev/null
+++ b/sys/kern/vfs_subr.c
@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2023-2024 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/vnode.h>
+#include <sys/errno.h>
+#include <sys/mount.h>
+#include <vm/dynalloc.h>
+#include <string.h>
+
+mountlist_t g_mountlist;
+
+int
+vfs_alloc_vnode(struct vnode **res, int type)
+{
+    struct vnode *vp = dynalloc(sizeof(struct vnode));
+
+    if (vp == NULL) {
+        return -ENOMEM;
+    }
+
+    memset(vp, 0, sizeof(*vp));
+    vp->type = type;
+    *res = vp;
+    return 0;
+}
+
+/*
+ * Allocate a mount structure.
+ *
+ * @vp: Vnode this mount structure covers.
+ * @fip: File system information.
+ */
+struct mount *
+vfs_alloc_mount(struct vnode *vp, struct fs_info *fip)
+{
+    struct mount *mp;
+
+    mp = dynalloc(sizeof(*mp));
+
+    if (mp == NULL) {
+        return NULL;
+    }
+
+    memset(mp, 0, sizeof(*mp));
+    mp->vp = vp;
+    mp->mnt_ops = fip->vfsops;
+    return mp;
+}
+
+/*
+ * Release a vnode and its resources from
+ * memory.
+ */
+int
+vfs_release_vnode(struct vnode *vp)
+{
+    const struct vops *vops = vp->vops;
+    int status = 0;
+
+    if (vp == NULL) {
+        return -EINVAL;
+    }
+
+    if (vops->reclaim != NULL) {
+        status = vops->reclaim(vp);
+    }
+
+    dynfree(vp);
+    return status;
+}
+
+int
+vfs_vop_lookup(struct vnode *vp, struct vop_lookup_args *args)
+{
+    const struct vops *vops = vp->vops;
+
+    if (vops == NULL)
+        return -EIO;
+    if (vops->lookup == NULL)
+        return -EIO;
+
+    return vops->lookup(args);
+}
+
+int
+vfs_vop_read(struct vnode *vp, struct sio_txn *sio)
+{
+    const struct vops *vops = vp->vops;
+
+    if (vops == NULL)
+        return -EIO;
+    if (vops->read == NULL)
+        return -EIO;
+
+    return vops->read(vp, sio);
+}