root/fs/nfsctl.c

DEFINITIONS

1. do_open
2. sys_nfsservctl

/*
 *      fs/nfsctl.c
 *
 *      This should eventually move to userland.
 *
 */
#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;
        struct vfsmount *mnt;
        int error;

        mnt = do_kern_mount("nfsd", 0, "nfsd", NULL);
        if (IS_ERR(mnt))
                return (struct file *)mnt;

        error = vfs_path_lookup(mnt->mnt_root, mnt, name, 0, &nd);
        mntput(mnt);    /* drop do_kern_mount reference */
        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.path.dentry, nd.path.mnt, flags);

        path_put(&nd.path);
        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)
        },
};

long
asmlinkage 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;
}