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/sunrpc/svc.h>
  11#include <linux/nfsd/nfsd.h>
  12#include <linux/nfsd/syscall.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,MAY_READ|MAY_WRITE,FMODE_READ|FMODE_WRITE);
  40        else
  41                error = may_open(&nd, MAY_WRITE, FMODE_WRITE);
  42
  43        if (!error)
  44                return dentry_open(nd.path.dentry, nd.path.mnt, flags);
  45
  46        path_put(&nd.path);
  47        return ERR_PTR(error);
  48}
  49
  50static struct {
  51        char *name; int wsize; int rsize;
  52} map[] = {
  53        [NFSCTL_SVC] = {
  54                .name   = ".svc",
  55                .wsize  = sizeof(struct nfsctl_svc)
  56        },
  57        [NFSCTL_ADDCLIENT] = {
  58                .name   = ".add",
  59                .wsize  = sizeof(struct nfsctl_client)
  60        },
  61        [NFSCTL_DELCLIENT] = {
  62                .name   = ".del",
  63                .wsize  = sizeof(struct nfsctl_client)
  64        },
  65        [NFSCTL_EXPORT] = {
  66                .name   = ".export",
  67                .wsize  = sizeof(struct nfsctl_export)
  68        },
  69        [NFSCTL_UNEXPORT] = {
  70                .name   = ".unexport",
  71                .wsize  = sizeof(struct nfsctl_export)
  72        },
  73        [NFSCTL_GETFD] = {
  74                .name   = ".getfd",
  75                .wsize  = sizeof(struct nfsctl_fdparm),
  76                .rsize  = NFS_FHSIZE
  77        },
  78        [NFSCTL_GETFS] = {
  79                .name   = ".getfs",
  80                .wsize  = sizeof(struct nfsctl_fsparm),
  81                .rsize  = sizeof(struct knfsd_fh)
  82        },
  83};
  84
  85SYSCALL_DEFINE3(nfsservctl, int, cmd, struct nfsctl_arg __user *, arg,
  86                void __user *, res)
  87{
  88        struct file *file;
  89        void __user *p = &arg->u;
  90        int version;
  91        int err;
  92
  93        if (copy_from_user(&version, &arg->ca_version, sizeof(int)))
  94                return -EFAULT;
  95
  96        if (version != NFSCTL_VERSION)
  97                return -EINVAL;
  98
  99        if (cmd < 0 || cmd >= ARRAY_SIZE(map) || !map[cmd].name)
 100                return -EINVAL;
 101
 102        file = do_open(map[cmd].name, map[cmd].rsize ? O_RDWR : O_WRONLY);      
 103        if (IS_ERR(file))
 104                return PTR_ERR(file);
 105        err = file->f_op->write(file, p, map[cmd].wsize, &file->f_pos);
 106        if (err >= 0 && map[cmd].rsize)
 107                err = file->f_op->read(file, res, map[cmd].rsize, &file->f_pos);
 108        if (err >= 0)
 109                err = 0;
 110        fput(file);
 111        return err;
 112}
 113