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/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 <asm/uaccess.h>
  16
  17 /*
  18  * open a file on nfsd fs
  19  */
  20
  21 struct vfsmount *do_kern_mount(const char *type, int flags, char *name, void *data);
  22
  23 static struct file *do_open(char *name, int flags)
  24 {
  25         struct nameidata nd;
  26         int error;
  27
  28         nd.mnt = do_kern_mount("nfsd", 0, "nfsd", NULL);
  29
  30         if (IS_ERR(nd.mnt))
  31                 return (struct file *)nd.mnt;
  32
  33         nd.dentry = dget(nd.mnt->mnt_root);
  34         nd.last_type = LAST_ROOT;
  35         nd.flags = 0;
  36
  37         error = path_walk(name, &nd);
  38         if (error)
  39                 return ERR_PTR(error);
  40
  41         if (flags == O_RDWR)
  42                 error = may_open(&nd,MAY_READ|MAY_WRITE,FMODE_READ|FMODE_WRITE);
  43         else
  44                 error = may_open(&nd, MAY_WRITE, FMODE_WRITE);
  45
  46         if (!error)
  47                 return dentry_open(nd.dentry, nd.mnt, flags);
  48
  49         path_release(&nd);
  50         return ERR_PTR(error);
  51 }
  52
  53 static struct {
  54         char *name; int wsize; int rsize;
  55 } map[] = {
  56         [NFSCTL_SVC]={"svc", sizeof(struct nfsctl_svc)},
  57         [NFSCTL_ADDCLIENT]={"add", sizeof(struct nfsctl_client)},
  58         [NFSCTL_DELCLIENT]={"del", sizeof(struct nfsctl_client)},
  59         [NFSCTL_EXPORT]={"export", sizeof(struct nfsctl_export)},
  60         [NFSCTL_UNEXPORT]={"unexport", sizeof(struct nfsctl_export)},
  61 #ifdef notyet
  62         [NFSCTL_UGIDUPDATE]={"ugid", sizeof(struct nfsctl_uidmap)},
  63 #endif
  64         [NFSCTL_GETFD]={"getfd", sizeof(struct nfsctl_fdparm), NFS_FHSIZE},
  65         [NFSCTL_GETFS]={"getfs", sizeof(struct nfsctl_fsparm), sizeof(struct knfsd_fh)},
  66 };
  67
  68 long
  69 asmlinkage sys_nfsservctl(int cmd, struct nfsctl_arg *arg, void *res)
  70 {
  71         struct file *file;
  72         void *p = &arg->u;
  73         int version;
  74         int err;
  75
  76         if (copy_from_user(&version, &arg->ca_version, sizeof(int)))
  77                 return -EFAULT;
  78
  79         if (version != NFSCTL_VERSION) {
  80                 printk(KERN_WARNING "nfsd: incompatible version in syscall.\n");
  81                 return -EINVAL;
  82         }
  83
  84         if (cmd < 0 || cmd >= sizeof(map)/sizeof(map[0]) || !map[cmd].name)
  85                 return -EINVAL;
  86
  87         file = do_open(map[cmd].name, map[cmd].rsize ? O_RDWR : O_WRONLY);
  88         if (IS_ERR(file))
  89                 return PTR_ERR(file);
  90         err = file->f_op->write(file, p, map[cmd].wsize, &file->f_pos);
  91         if (err >= 0 && map[cmd].rsize)
  92                 err = file->f_op->read(file, res, map[cmd].rsize, &file->f_pos);
  93         if (err >= 0)
  94                 err = 0;
  95         fput(file);
  96         return err;
  97 }