/* *	fs/nfsctl.c * *	This should eventually move to userland. * */#include <linux/config.h>#include <linux/types.h>#include <linux/file.h>#include <linux/fs.h>#include <linux/sunrpc/svc.h>#include <linux/nfsd/nfsd.h>#include <linux/nfsd/syscall.h>#include <linux/linkage.h>#include <linux/namei.h>#include <linux/mount.h>#include <linux/syscalls.h>#include <asm/uaccess.h> /* * open a file on nfsd fs */ static struct file *do_open(char *name, int flags){	struct nameidata nd;	int error; 	nd.mnt = do_kern_mount("nfsd", 0, "nfsd", NULL); 	if (IS_ERR(nd.mnt))		return (struct file *)nd.mnt; 	nd.dentry = dget(nd.mnt->mnt_root);	nd.last_type = LAST_ROOT;	nd.flags = 0;	nd.depth = 0; 	error = path_walk(name, &nd);	if (error)		return ERR_PTR(error); 	if (flags == O_RDWR)		error = may_open(&nd,MAY_READ|MAY_WRITE,FMODE_READ|FMODE_WRITE);	else		error = may_open(&nd, MAY_WRITE, FMODE_WRITE); 	if (!error)		return dentry_open(nd.dentry, nd.mnt, flags); 	path_release(&nd);	return ERR_PTR(error);} static struct {	char *name; int wsize; int rsize;} map[] = {	[NFSCTL_SVC] = {		.name	= ".svc",		.wsize	= sizeof(struct nfsctl_svc)	},	[NFSCTL_ADDCLIENT] = {		.name	= ".add",		.wsize	= sizeof(struct nfsctl_client)	},	[NFSCTL_DELCLIENT] = {		.name	= ".del",		.wsize	= sizeof(struct nfsctl_client)	},	[NFSCTL_EXPORT] = {		.name	= ".export",		.wsize	= sizeof(struct nfsctl_export)	},	[NFSCTL_UNEXPORT] = {		.name	= ".unexport",		.wsize	= sizeof(struct nfsctl_export)	},	[NFSCTL_GETFD] = {		.name	= ".getfd",		.wsize	= sizeof(struct nfsctl_fdparm),		.rsize	= NFS_FHSIZE	},	[NFSCTL_GETFS] = {		.name	= ".getfs",		.wsize	= sizeof(struct nfsctl_fsparm),		.rsize	= sizeof(struct knfsd_fh)	},}; longasmlinkage sys_nfsservctl(int cmd, struct nfsctl_arg __user *arg, void __user *res){	struct file *file;	void __user *p = &arg->u;	int version;	int err; 	if (copy_from_user(&version, &arg->ca_version, sizeof(int)))		return -EFAULT; 	if (version != NFSCTL_VERSION)		return -EINVAL; 	if (cmd < 0 || cmd >= ARRAY_SIZE(map) || !map[cmd].name)		return -EINVAL; 	file = do_open(map[cmd].name, map[cmd].rsize ? O_RDWR : O_WRONLY);		if (IS_ERR(file))		return PTR_ERR(file);	err = file->f_op->write(file, p, map[cmd].wsize, &file->f_pos);	if (err >= 0 && map[cmd].rsize)		err = file->f_op->read(file, res, map[cmd].rsize, &file->f_pos);	if (err >= 0)		err = 0;	fput(file);	return err;}