LXR linux/fs/nfsctl.c

   1/*
   2 *      fs/nfsctl.c
   3 *
   4 *      This should eventually move to userland.
   5 *
   6 */
   7#include <linux/types.h>
   8#include <linux/file.h>
   9#include <linux/fs.h>
  10#include <linux/nfsd/syscall.h>
  11#include <linux/cred.h>
  12#include <linux/sched.h>
  13#include <linux/linkage.h>
  14#include <linux/namei.h>
  15#include <linux/mount.h>
  16#include <linux/syscalls.h>
  17#include <asm/uaccess.h>
  18
  19/*
  20 * open a file on nfsd fs
  21 */
  22
  23static struct file *do_open(char *name, int flags)
  24{
  25        struct nameidata nd;
  26        struct vfsmount *mnt;
  27        int error;
  28
  29        mnt = do_kern_mount("nfsd", 0, "nfsd", NULL);
  30        if (IS_ERR(mnt))
  31                return (struct file *)mnt;
  32
  33        error = vfs_path_lookup(mnt->mnt_root, mnt, name, 0, &nd);
  34        mntput(mnt);    /* drop do_kern_mount reference */
  35        if (error)
  36                return ERR_PTR(error);
  37
  38        if (flags == O_RDWR)
  39                error = may_open(&nd.path, MAY_READ|MAY_WRITE, flags);
  40        else
  41                error = may_open(&nd.path, MAY_WRITE, flags);
  42
  43        if (!error)
  44                return dentry_open(nd.path.dentry, nd.path.mnt, flags,
  45                                   current_cred());
  46
  47        path_put(&nd.path);
  48        return ERR_PTR(error);
  49}
  50
  51static struct {
  52        char *name; int wsize; int rsize;
  53} map[] = {
  54        [NFSCTL_SVC] = {
  55                .name   = ".svc",
  56                .wsize  = sizeof(struct nfsctl_svc)
  57        },
  58        [NFSCTL_ADDCLIENT] = {
  59                .name   = ".add",
  60                .wsize  = sizeof(struct nfsctl_client)
  61        },
  62        [NFSCTL_DELCLIENT] = {
  63                .name   = ".del",
  64                .wsize  = sizeof(struct nfsctl_client)
  65        },
  66        [NFSCTL_EXPORT] = {
  67                .name   = ".export",
  68                .wsize  = sizeof(struct nfsctl_export)
  69        },
  70        [NFSCTL_UNEXPORT] = {
  71                .name   = ".unexport",
  72                .wsize  = sizeof(struct nfsctl_export)
  73        },
  74        [NFSCTL_GETFD] = {
  75                .name   = ".getfd",
  76                .wsize  = sizeof(struct nfsctl_fdparm),
  77                .rsize  = NFS_FHSIZE
  78        },
  79        [NFSCTL_GETFS] = {
  80                .name   = ".getfs",
  81                .wsize  = sizeof(struct nfsctl_fsparm),
  82                .rsize  = sizeof(struct knfsd_fh)
  83        },
  84};
  85
  86SYSCALL_DEFINE3(nfsservctl, int, cmd, struct nfsctl_arg __user *, arg,
  87                void __user *, res)
  88{
  89        struct file *file;
  90        void __user *p = &arg->u;
  91        int version;
  92        int err;
  93
  94        if (copy_from_user(&version, &arg->ca_version, sizeof(int)))
  95                return -EFAULT;
  96
  97        if (version != NFSCTL_VERSION)
  98                return -EINVAL;
  99
 100        if (cmd < 0 || cmd >= ARRAY_SIZE(map) || !map[cmd].name)
 101                return -EINVAL;
 102
 103        file = do_open(map[cmd].name, map[cmd].rsize ? O_RDWR : O_WRONLY);      
 104        if (IS_ERR(file))
 105                return PTR_ERR(file);
 106        err = file->f_op->write(file, p, map[cmd].wsize, &file->f_pos);
 107        if (err >= 0 && map[cmd].rsize)
 108                err = file->f_op->read(file, res, map[cmd].rsize, &file->f_pos);
 109        if (err >= 0)
 110                err = 0;
 111        fput(file);
 112        return err;
 113}
 114