LXR linux-bk/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
  22static 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
  52static 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
  87long
  88asmlinkage 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}
 117