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 <linux/mount.h>
  16 #include <asm/uaccess.h>
  17
  18 /*
  19  * open a file on nfsd fs
  20  */
  21
  22 static struct file *do_open(char *name, int flags)
  23 {
  24         struct nameidata nd;
  25         int error;
  26
  27         nd.mnt = do_kern_mount("nfsd", 0, "nfsd", NULL);
  28
  29         if (IS_ERR(nd.mnt))
  30                 return (struct file *)nd.mnt;
  31
  32         nd.dentry = dget(nd.mnt->mnt_root);
  33         nd.last_type = LAST_ROOT;
  34         nd.flags = 0;
  35         nd.depth = 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] = {
  57                 .name   = ".svc",
  58                 .wsize  = sizeof(struct nfsctl_svc)
  59         },
  60         [NFSCTL_ADDCLIENT] = {
  61                 .name   = ".add",
  62                 .wsize  = sizeof(struct nfsctl_client)
  63         },
  64         [NFSCTL_DELCLIENT] = {
  65                 .name   = ".del",
  66                 .wsize  = sizeof(struct nfsctl_client)
  67         },
  68         [NFSCTL_EXPORT] = {
  69                 .name   = ".export",
  70                 .wsize  = sizeof(struct nfsctl_export)
  71         },
  72         [NFSCTL_UNEXPORT] = {
  73                 .name   = ".unexport",
  74                 .wsize  = sizeof(struct nfsctl_export)
  75         },
  76         [NFSCTL_GETFD] = {
  77                 .name   = ".getfd",
  78                 .wsize  = sizeof(struct nfsctl_fdparm),
  79                 .rsize  = NFS_FHSIZE
  80         },
  81         [NFSCTL_GETFS] = {
  82                 .name   = ".getfs",
  83                 .wsize  = sizeof(struct nfsctl_fsparm),
  84                 .rsize  = sizeof(struct knfsd_fh)
  85         },
  86 };
  87
  88 long
  89 asmlinkage sys_nfsservctl(int cmd, struct nfsctl_arg __user *arg, void __user *res)
  90 {
  91         struct file *file;
  92         void __user *p = &arg->u;
  93         int version;
  94         int err;
  95
  96         if (copy_from_user(&version, &arg->ca_version, sizeof(int)))
  97                 return -EFAULT;
  98
  99         if (version != NFSCTL_VERSION) {
 100                 printk(KERN_WARNING "nfsd: incompatible version in syscall.\n");
 101                 return -EINVAL;
 102         }
 103
 104         if (cmd < 0 || cmd >= sizeof(map)/sizeof(map[0]) || !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 }