kernel: Add initramfs and initial VFS code

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

4 files changed, 279 insertions, 0 deletions

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);
+}