fs/nfsctl.c

   1 /*
   2  *      fs/nfsctl.c
   3  *
   4  *      This should eventually move to userland.
   5  *
   6  */
   7 #include <linux/config.h>
   8 #include <linux/types.h>
   9 #include <linux/file.h>
  10 #include <linux/fs.h>
  11 #include <linux/sunrpc/svc.h>
  12 #include <linux/nfsd/nfsd.h>
  13 #include <linux/nfsd/syscall.h>
  14 #include <linux/linkage.h>
  15 #include <linux/namei.h>
  16 #include <linux/mount.h>
  17 #include <linux/syscalls.h>
  18 #include <asm/uaccess.h>
  19
  20 /*
  21  * open a file on nfsd fs
  22  */
  23
  24 static struct file *do_open(char *name, int flags)
  25 {
  26         struct nameidata nd;
  27         int error;
  28
  29         nd.mnt = do_kern_mount("nfsd", 0, "nfsd", NULL);
  30
  31         if (IS_ERR(nd.mnt))
  32                 return (struct file *)nd.mnt;
  33
  34         nd.dentry = dget(nd.mnt->mnt_root);
  35         nd.last_type = LAST_ROOT;
  36         nd.flags = 0;
  37         nd.depth = 0;
  38
  39         error = path_walk(name, &nd);
  40         if (error)
  41                 return ERR_PTR(error);
  42
  43         if (flags == O_RDWR)
  44                 error = may_open(&nd,MAY_READ|MAY_WRITE,FMODE_READ|FMODE_WRITE);
  45         else
  46                 error = may_open(&nd, MAY_WRITE, FMODE_WRITE);
  47
  48         if (!error)
  49                 return dentry_open(nd.dentry, nd.mnt, flags);
  50
  51         path_release(&nd);
  52         return ERR_PTR(error);
  53 }
  54
  55 static struct {
  56         char *name; int wsize; int rsize;
  57 } map[] = {
  58         [NFSCTL_SVC] = {
  59                 .name   = ".svc",
  60                 .wsize  = sizeof(struct nfsctl_svc)
  61         },
  62         [NFSCTL_ADDCLIENT] = {
  63                 .name   = ".add",
  64                 .wsize  = sizeof(struct nfsctl_client)
  65         },
  66         [NFSCTL_DELCLIENT] = {
  67                 .name   = ".del",
  68                 .wsize  = sizeof(struct nfsctl_client)
  69         },
  70         [NFSCTL_EXPORT] = {
  71                 .name   = ".export",
  72                 .wsize  = sizeof(struct nfsctl_export)
  73         },
  74         [NFSCTL_UNEXPORT] = {
  75                 .name   = ".unexport",
  76                 .wsize  = sizeof(struct nfsctl_export)
  77         },
  78         [NFSCTL_GETFD] = {
  79                 .name   = ".getfd",
  80                 .wsize  = sizeof(struct nfsctl_fdparm),
  81                 .rsize  = NFS_FHSIZE
  82         },
  83         [NFSCTL_GETFS] = {
  84                 .name   = ".getfs",
  85                 .wsize  = sizeof(struct nfsctl_fsparm),
  86                 .rsize  = sizeof(struct knfsd_fh)
  87         },
  88 };
  89
  90 long
  91 asmlinkage sys_nfsservctl(int cmd, struct nfsctl_arg __user *arg, void __user *res)
  92 {
  93         struct file *file;
  94         void __user *p = &arg->u;
  95         int version;
  96         int err;
  97
  98         if (copy_from_user(&version, &arg->ca_version, sizeof(int)))
  99                 return -EFAULT;
 100
 101         if (version != NFSCTL_VERSION)
 102                 return -EINVAL;
 103
 104         if (cmd < 0 || cmd >= ARRAY_SIZE(map) || !map[cmd].name)
 105                 return -EINVAL;
 106
 107         file = do_open(map[cmd].name, map[cmd].rsize ? O_RDWR : O_WRONLY);
 108         if (IS_ERR(file))
 109                 return PTR_ERR(file);
 110         err = file->f_op->write(file, p, map[cmd].wsize, &file->f_pos);
 111         if (err >= 0 && map[cmd].rsize)
 112                 err = file->f_op->read(file, res, map[cmd].rsize, &file->f_pos);
 113         if (err >= 0)
 114                 err = 0;
 115         fput(file);
 116         return err;
 117 }