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
  36         error = path_walk(name, &nd);
  37         if (error)
  38                 return ERR_PTR(error);
  39
  40         if (flags == O_RDWR)
  41                 error = may_open(&nd,MAY_READ|MAY_WRITE,FMODE_READ|FMODE_WRITE);
  42         else
  43                 error = may_open(&nd, MAY_WRITE, FMODE_WRITE);
  44
  45         if (!error)
  46                 return dentry_open(nd.dentry, nd.mnt, flags);
  47
  48         path_release(&nd);
  49         return ERR_PTR(error);
  50 }
  51
  52 static struct {
  53         char *name; int wsize; int rsize;
  54 } map[] = {
  55         [NFSCTL_SVC] = {
  56                 .name   = ".svc",
  57                 .wsize  = sizeof(struct nfsctl_svc)
  58         },
  59         [NFSCTL_ADDCLIENT] = {
  60                 .name   = ".add",
  61                 .wsize  = sizeof(struct nfsctl_client)
  62         },
  63         [NFSCTL_DELCLIENT] = {
  64                 .name   = ".del",
  65                 .wsize  = sizeof(struct nfsctl_client)
  66         },
  67         [NFSCTL_EXPORT] = {
  68                 .name   = ".export",
  69                 .wsize  = sizeof(struct nfsctl_export)
  70         },
  71         [NFSCTL_UNEXPORT] = {
  72                 .name   = ".unexport",
  73                 .wsize  = sizeof(struct nfsctl_export)
  74         },
  75         [NFSCTL_GETFD] = {
  76                 .name   = ".getfd",
  77                 .wsize  = sizeof(struct nfsctl_fdparm),
  78                 .rsize  = NFS_FHSIZE
  79         },
  80         [NFSCTL_GETFS] = {
  81                 .name   = ".getfs",
  82                 .wsize  = sizeof(struct nfsctl_fsparm),
  83                 .rsize  = sizeof(struct knfsd_fh)
  84         },
  85 };
  86
  87 long
  88 asmlinkage sys_nfsservctl(int cmd, struct nfsctl_arg __user *arg, void __user *res)
  89 {
  90         struct file *file;
  91         void __user *p = &arg->u;
  92         int version;
  93         int err;
  94
  95         if (copy_from_user(&version, &arg->ca_version, sizeof(int)))
  96                 return -EFAULT;
  97
  98         if (version != NFSCTL_VERSION) {
  99                 printk(KERN_WARNING "nfsd: incompatible version in syscall.\n");
 100                 return -EINVAL;
 101         }
 102
 103         if (cmd < 0 || cmd >= sizeof(map)/sizeof(map[0]) || !map[cmd].name)
 104                 return -EINVAL;
 105
 106         file = do_open(map[cmd].name, map[cmd].rsize ? O_RDWR : O_WRONLY);
 107         if (IS_ERR(file))
 108                 return PTR_ERR(file);
 109         err = file->f_op->write(file, p, map[cmd].wsize, &file->f_pos);
 110         if (err >= 0 && map[cmd].rsize)
 111                 err = file->f_op->read(file, res, map[cmd].rsize, &file->f_pos);
 112         if (err >= 0)
 113                 err = 0;
 114         fput(file);
 115         return err;
 116 }