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
  23 static 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
  38 static 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
  73 SYSCALL_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 }