/* * xenfs.c - a filesystem for passing info between the a domain and * the hypervisor. * * 2008-10-07 Alex Zeffertt Replaced /proc/xen/xenbus with xenfs filesystem * and /proc/xen compatibility mount point. * Turned xenfs into a loadable module. */ #include <linux/kernel.h> #include <linux/errno.h> #include <linux/module.h> #include <linux/fs.h> #include <linux/magic.h> #include "xenfs.h" #include <asm/xen/hypervisor.h> MODULE_DESCRIPTION("Xen filesystem"); MODULE_LICENSE("GPL"); static ssize_t capabilities_read(struct file *file, char __user *buf, size_t size, loff_t *off) { char *tmp = ""; if (xen_initial_domain()) tmp = "control_d\n"; return simple_read_from_buffer(buf, size, off, tmp, strlen(tmp)); } static const struct file_operations capabilities_file_ops = { .read = capabilities_read, }; static int xenfs_fill_super(struct super_block *sb, void *data, int silent) { static struct tree_descr xenfs_files[] = { [1] = {}, { "xenbus", &xenbus_file_ops, S_IRUSR|S_IWUSR }, { "capabilities", &capabilities_file_ops, S_IRUGO }, {""}, }; return simple_fill_super(sb, XENFS_SUPER_MAGIC, xenfs_files); } static int xenfs_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, struct vfsmount *mnt) { return get_sb_single(fs_type, flags, data, xenfs_fill_super, mnt); } static struct file_system_type xenfs_type = { .owner = THIS_MODULE, .name = "xenfs", .get_sb = xenfs_get_sb, .kill_sb = kill_litter_super, }; static int __init xenfs_init(void) { if (xen_pv_domain()) return register_filesystem(&xenfs_type); printk(KERN_INFO "XENFS: not registering filesystem on non-xen platform\n"); return 0; } static void __exit xenfs_exit(void) { if (xen_pv_domain()) unregister_filesystem(&xenfs_type); } module_init(xenfs_init); module_exit(xenfs_exit);