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>

1 files changed, 119 insertions, 0 deletions

diff --git a/src/sys/os/vfs_mount.c b/src/sys/os/vfs_mount.c
new file mode 100644
index 0000000..f1d7ffd
--- /dev/null
+++ b/src/sys/os/vfs_mount.c
@@ -0,0 +1,119 @@
+/*
+ * 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.
+ */
+
+#include <sys/types.h>
+#include <sys/syslog.h>
+#include <sys/errno.h>
+#include <sys/cdefs.h>
+#include <sys/mount.h>
+#include <os/vfs.h>
+#include <string.h>
+
+/*
+ * Represents the root mountlist, every other
+ * mountpoint is put here.
+ */
+static struct mountlist root;
+
+/*
+ * Mount a filesystem
+ */
+int
+mount(struct mount_args *margs, uint32_t flags)
+{
+    const struct vfsops *vfsops;
+    struct fs_info *fip = NULL;
+    int error;
+
+    if (margs == NULL) {
+        return -EINVAL;
+    }
+
+    /* XXX: Unused as of now */
+    (void)margs->source;
+    (void)margs->target;
+    (void)margs->data;
+
+    /* XXX: Requires fstype for now */
+    if (margs->fstype == NULL) {
+        return -ENOENT;
+    }
+
+    /*
+     * Now we go through each entry of the filesystem
+     * table and if it matches the filesystem type,
+     * we're good.
+     */
+    for (uint8_t i = 0;; ++i) {
+        error = vfs_by_index(i, &fip);
+        if (error != 0) {
+            return -ENOENT;
+        }
+
+        if (strcmp(fip->name, margs->fstype) == 0) {
+            break;
+        }
+    }
+
+
+    /* Sanity check */
+    if (__unlikely(fip == NULL)) {
+        printf("mount: got NULL filesystem info\n");
+        return -ENOENT;
+    }
+
+    vfsops = fip->vfsops;
+    if (__unlikely(vfsops->mount == NULL)) {
+        printf("mount: fs does not implement mount!\n");
+        return -EIO;
+    }
+
+    vfsops->mount(fip, margs);
+    return 0;
+}
+
+/*
+ * Initialize the mountlist
+ */
+int
+mountlist_init(struct mountlist *mlp)
+{
+    if (mlp == NULL) {
+        mlp = &root;
+    }
+
+    /* Don't initialize twice */
+    if (mlp->i) {
+        return -EPERM;
+    }
+
+    TAILQ_INIT(&mlp->list);
+    mlp->i = 1;
+    return 0;
+}