usr/src/lib/libc/port/sys/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) 2010, Oracle and/or its affiliates. All rights reserved.
  24  */
  25
  26 #include "lint.h"
  27 #include <unistd.h>
  28 #include <fcntl.h>
  29 #include <sys/syscall.h>
  30
  31 extern  int __xpg4; /* defined in port/gen/xpg4.c; 0 if not xpg4/xpg4v2 */
  32
  33 int
  34 linkat(int fd1, const char *path1, int fd2, const char *path2, int flag)
  35 {
  36         return (syscall(SYS_linkat, fd1, path1, fd2, path2, flag));
  37 }
  38
  39 #pragma weak _link = link
  40 int
  41 link(const char *path1, const char *path2)
  42 {
  43         /*
  44          * XPG4v2 link() requires that the link count of a symbolic
  45          * link target be updated rather than the link itself.  This
  46          * matches SunOS 4.x and other BSD based implementations.
  47          * However, the SVR4 merge apparently introduced the change
  48          * that allowed link(src, dest) when "src" was a symbolic link,
  49          * to create "dest" as a hard link to "src".  Hence, the link
  50          * count of the symbolic link is updated rather than the target
  51          * of the symbolic link. This latter behavior remains for
  52          * non-XPG4 based environments. For a more detailed discussion,
  53          * see bug 1256170.
  54          */
  55         return (linkat(AT_FDCWD, path1, AT_FDCWD, path2,
  56             (__xpg4 != 0) ? AT_SYMLINK_FOLLOW : 0));
  57 }