kernel/syscall/link.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved.
  24  */
  25
  26 /*      Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T     */
  27 /*        All Rights Reserved   */
  28
  29 /*
  30  * Portions of this source code were derived from Berkeley 4.3 BSD
  31  * under license from the Regents of the University of California.
  32  */
  33
  34 #include <sys/param.h>
  35 #include <sys/isa_defs.h>
  36 #include <sys/types.h>
  37 #include <sys/sysmacros.h>
  38 #include <sys/systm.h>
  39 #include <sys/errno.h>
  40 #include <sys/vnode.h>
  41 #include <sys/file.h>
  42 #include <sys/fcntl.h>
  43 #include <sys/uio.h>
  44 #include <sys/debug.h>
  45
  46 /*
  47  * Make a hard link.
  48  */
  49 int
  50 linkat(int ffd, char *from, int tfd, char *to, int flag)
  51 {
  52         vnode_t *fstartvp = NULL;
  53         vnode_t *tstartvp = NULL;
  54         enum symfollow follow;
  55         int error;
  56
  57         if (flag & ~AT_SYMLINK_FOLLOW)
  58                 return (set_errno(EINVAL));
  59         follow = (flag & AT_SYMLINK_FOLLOW)? FOLLOW : NO_FOLLOW;
  60
  61         if (from == NULL || to == NULL)
  62                 return (set_errno(EFAULT));
  63         if ((error = fgetstartvp(ffd, from, &fstartvp)) != 0)
  64                 goto out;
  65         if ((error = fgetstartvp(tfd, to, &tstartvp)) != 0)
  66                 goto out;
  67
  68         error = vn_linkat(fstartvp, from, follow, tstartvp, to, UIO_USERSPACE);
  69
  70 out:
  71         if (fstartvp != NULL)
  72                 VN_RELE(fstartvp);
  73         if (tstartvp != NULL)
  74                 VN_RELE(tstartvp);
  75         if (error)
  76                 return (set_errno(error));
  77         return (0);
  78 }