+/**
+ * @file ramfs.c
+ * @author Lunaixsky
+ * @brief RamFS - a file system sit in RAM
+ * @version 0.1
+ * @date 2022-08-18
+ *
+ * @copyright Copyright (c) 2022
+ *
+ */
+#include <lunaix/fs.h>
+#include <lunaix/fs/ramfs.h>
+#include <lunaix/mm/valloc.h>
+
+/*
+ A RAM FS will play a role of being a root.
+
+ This is an temporary meaure as we don't have any concrete fs
+ yet. In the near future, we will have an ISO-9660 as our first
+ fs and mount our boot medium as root. And similar thing could
+ be done when we have installed our OS into hard disk, in that
+ case, our rootfs will be something like ext2.
+
+ RamFS vs. TwiFS: Indeed, they are both fs that lives in RAM so
+ there is no foundmentally differences. However, TwiFS is designed
+ to be a 'virtual FIlesystem for KERnel space' (FIKER), so other
+ kernel sub-modules can just create node and attach their own
+ implementation of read/write, without brothering to create a
+ full featured concrete filesystem. This particularly useful for
+ kernel state exposure. In Lunaix, TwiFS is summation of procfs,
+ sysfs and kernfs in Linux world.
+
+ However, there is a smell of bad-design in the concept of TwiFS.
+ Since it tries to integrate too much responsibility. The TwiFS may
+ be replaced by more specific fs in the future.
+
+ On the other hand, RamFS is designed to be act like a dummy fs
+ that just ensure 'something there at least' and thus provide basic
+ 'mountibility' for other fs.
+*/
+
+volatile static inode_t ino = 0;
+
+extern const struct v_inode_ops ramfs_inode_ops;
+
+int
+ramfs_readdir(struct v_file* file, struct dir_context* dctx)
+{
+ int i = 0;
+ struct v_dnode *pos, *n;
+ llist_for_each(pos, n, &file->dnode->children, siblings)
+ {
+ if (i++ >= dctx->index) {
+ dctx->read_complete_callback(
+ dctx, pos->name.value, pos->name.len, 0);
+ return 1;
+ }
+ }
+ return 0;
+}
+
+int
+ramfs_mkdir(struct v_inode* this, struct v_dnode* dnode)
+{
+ struct v_inode* inode = vfs_i_alloc(dnode->super_block);
+ inode->itype = VFS_IFDIR;
+
+ vfs_i_addhash(inode);
+ vfs_assign_inode(dnode, inode);
+
+ return 0;
+}
+
+int
+ramfs_create(struct v_inode* this, struct v_dnode* dnode)
+{
+ struct v_inode* inode = vfs_i_alloc(dnode->super_block);
+ inode->itype = VFS_IFFILE;
+
+ vfs_i_addhash(inode);
+ vfs_assign_inode(dnode, inode);
+
+ return 0;
+}
+
+void
+ramfs_inode_init(struct v_superblock* vsb, struct v_inode* inode)
+{
+ inode->id = ino++;
+ inode->ops = &ramfs_inode_ops;
+ inode->default_fops = &default_file_ops;
+}
+
+int
+ramfs_mount(struct v_superblock* vsb, struct v_dnode* mount_point)
+{
+ vsb->ops.init_inode = ramfs_inode_init;
+
+ struct v_inode* inode = vfs_i_alloc(vsb);
+ inode->itype = VFS_IFDIR;
+
+ vfs_i_addhash(inode);
+ vfs_assign_inode(mount_point, inode);
+
+ return 0;
+}
+
+int
+ramfs_unmount(struct v_superblock* vsb)
+{
+ return 0;
+}
+
+void
+ramfs_init()
+{
+ struct filesystem* ramfs = fsm_new_fs("ramfs", 5);
+ ramfs->mount = ramfs_mount;
+ ramfs->unmount = ramfs_unmount;
+
+ fsm_register(ramfs);
+}
+
+const struct v_inode_ops ramfs_inode_ops = { .mkdir = ramfs_mkdir,
+ .rmdir = default_inode_rmdir,
+ .dir_lookup =
+ default_inode_dirlookup,
+ .create = ramfs_create,
+ .open = default_inode_open,
+ .rename = default_inode_rename };
\ No newline at end of file
git://scm.lunaixsky.com / lunaix-os.git / commitdiff