linux/fs/nfsctl.c
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   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 vfsmount *mnt;
  26        struct file *file;
  27
  28        mnt = do_kern_mount("nfsd", 0, "nfsd", NULL);
  29        if (IS_ERR(mnt))
  30                return (struct file *)mnt;
  31
  32        file = file_open_root(mnt->mnt_root, mnt, name, flags);
  33
  34        mntput(mnt);    /* drop do_kern_mount reference */
  35        return file;
  36}
  37
  38static struct {
  39        char *name; int wsize; int rsize;
  40} map[] = {
  41        [NFSCTL_SVC] = {
  42                .name   = ".svc",
  43                .wsize  = sizeof(struct nfsctl_svc)
  44        },
  45        [NFSCTL_ADDCLIENT] = {
  46                .name   = ".add",
  47                .wsize  = sizeof(struct nfsctl_client)
  48        },
  49        [NFSCTL_DELCLIENT] = {
  50                .name   = ".del",
  51                .wsize  = sizeof(struct nfsctl_client)
  52        },
  53        [NFSCTL_EXPORT] = {
  54                .name   = ".export",
  55                .wsize  = sizeof(struct nfsctl_export)
  56        },
  57        [NFSCTL_UNEXPORT] = {
  58                .name   = ".unexport",
  59                .wsize  = sizeof(struct nfsctl_export)
  60        },
  61        [NFSCTL_GETFD] = {
  62                .name   = ".getfd",
  63                .wsize  = sizeof(struct nfsctl_fdparm),
  64                .rsize  = NFS_FHSIZE
  65        },
  66        [NFSCTL_GETFS] = {
  67                .name   = ".getfs",
  68                .wsize  = sizeof(struct nfsctl_fsparm),
  69                .rsize  = sizeof(struct knfsd_fh)
  70        },
  71};
  72
  73SYSCALL_DEFINE3(nfsservctl, int, cmd, struct nfsctl_arg __user *, arg,
  74                void __user *, res)
  75{
  76        struct file *file;
  77        void __user *p = &arg->u;
  78        int version;
  79        int err;
  80
  81        if (copy_from_user(&version, &arg->ca_version, sizeof(int)))
  82                return -EFAULT;
  83
  84        if (version != NFSCTL_VERSION)
  85                return -EINVAL;
  86
  87        if (cmd < 0 || cmd >= ARRAY_SIZE(map) || !map[cmd].name)
  88                return -EINVAL;
  89
  90        file = do_open(map[cmd].name, map[cmd].rsize ? O_RDWR : O_WRONLY);      
  91        if (IS_ERR(file))
  92                return PTR_ERR(file);
  93        err = file->f_op->write(file, p, map[cmd].wsize, &file->f_pos);
  94        if (err >= 0 && map[cmd].rsize)
  95                err = file->f_op->read(file, res, map[cmd].rsize, &file->f_pos);
  96        if (err >= 0)
  97                err = 0;
  98        fput(file);
  99        return err;
 100}
 101