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/sunrpc/svc.h>
  11#include <linux/nfsd/nfsd.h>
  12#include <linux/nfsd/syscall.h>
  13#include <linux/cred.h>
  14#include <linux/sched.h>
  15#include <linux/linkage.h>
  16#include <linux/namei.h>
  17#include <linux/mount.h>
  18#include <linux/syscalls.h>
  19#include <asm/uaccess.h>
  20
  21/*
  22 * open a file on nfsd fs
  23 */
  24
  25static struct file *do_open(char *name, int flags)
  26{
  27        struct nameidata nd;
  28        struct vfsmount *mnt;
  29        int error;
  30
  31        mnt = do_kern_mount("nfsd", 0, "nfsd", NULL);
  32        if (IS_ERR(mnt))
  33                return (struct file *)mnt;
  34
  35        error = vfs_path_lookup(mnt->mnt_root, mnt, name, 0, &nd);
  36        mntput(mnt);    /* drop do_kern_mount reference */
  37        if (error)
  38                return ERR_PTR(error);
  39
  40        if (flags == O_RDWR)
  41                error = may_open(&nd.path, MAY_READ|MAY_WRITE,
  42                                           FMODE_READ|FMODE_WRITE);
  43        else
  44                error = may_open(&nd.path, MAY_WRITE, FMODE_WRITE);
  45
  46        if (!error)
  47                return dentry_open(nd.path.dentry, nd.path.mnt, flags,
  48                                   current_cred());
  49
  50        path_put(&nd.path);
  51        return ERR_PTR(error);
  52}
  53
  54static struct {
  55        char *name; int wsize; int rsize;
  56} map[] = {
  57        [NFSCTL_SVC] = {
  58                .name   = ".svc",
  59                .wsize  = sizeof(struct nfsctl_svc)
  60        },
  61        [NFSCTL_ADDCLIENT] = {
  62                .name   = ".add",
  63                .wsize  = sizeof(struct nfsctl_client)
  64        },
  65        [NFSCTL_DELCLIENT] = {
  66                .name   = ".del",
  67                .wsize  = sizeof(struct nfsctl_client)
  68        },
  69        [NFSCTL_EXPORT] = {
  70                .name   = ".export",
  71                .wsize  = sizeof(struct nfsctl_export)
  72        },
  73        [NFSCTL_UNEXPORT] = {
  74                .name   = ".unexport",
  75                .wsize  = sizeof(struct nfsctl_export)
  76        },
  77        [NFSCTL_GETFD] = {
  78                .name   = ".getfd",
  79                .wsize  = sizeof(struct nfsctl_fdparm),
  80                .rsize  = NFS_FHSIZE
  81        },
  82        [NFSCTL_GETFS] = {
  83                .name   = ".getfs",
  84                .wsize  = sizeof(struct nfsctl_fsparm),
  85                .rsize  = sizeof(struct knfsd_fh)
  86        },
  87};
  88
  89SYSCALL_DEFINE3(nfsservctl, int, cmd, struct nfsctl_arg __user *, arg,
  90                void __user *, res)
  91{
  92        struct file *file;
  93        void __user *p = &arg->u;
  94        int version;
  95        int err;
  96
  97        if (copy_from_user(&version, &arg->ca_version, sizeof(int)))
  98                return -EFAULT;
  99
 100        if (version != NFSCTL_VERSION)
 101                return -EINVAL;
 102
 103        if (cmd < 0 || cmd >= ARRAY_SIZE(map) || !map[cmd].name)
 104                return -EINVAL;
 105
 106        file = do_open(map[cmd].name, map[cmd].rsize ? O_RDWR : O_WRONLY);      
 107        if (IS_ERR(file))
 108                return PTR_ERR(file);
 109        err = file->f_op->write(file, p, map[cmd].wsize, &file->f_pos);
 110        if (err >= 0 && map[cmd].rsize)
 111                err = file->f_op->read(file, res, map[cmd].rsize, &file->f_pos);
 112        if (err >= 0)
 113                err = 0;
 114        fput(file);
 115        return err;
 116}
 117