sysdeps/mach/hurd/linkat.c

   1 /* Make a link between file names relative to open directories.  Hurd version.
   2    Copyright (C) 2006-2018 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <fcntl.h>
  21 #include <stddef.h>
  22 #include <unistd.h>
  23 #include <hurd.h>
  24 #include <hurd/fd.h>
  25
  26
  27 /* Make a link to FROM relative to FROMFD called TO relative to TOFD.  */
  28 int
  29 linkat (int fromfd, const char *from, int tofd, const char *to, int flags)
  30 {
  31   error_t err;
  32   file_t oldfile, linknode, todir;
  33   char *toname;
  34
  35   /* POSIX says linkat doesn't follow symlinks by default, so pass
  36      O_NOLINK.  That can be overridden by AT_SYMLINK_FOLLOW in FLAGS.  */
  37   oldfile = __file_name_lookup_at (fromfd, flags, from, O_NOLINK, 0);
  38   if (oldfile == MACH_PORT_NULL)
  39     return -1;
  40
  41   /* The file_getlinknode RPC returns the port that should be passed to
  42      the receiving filesystem (the one containing TODIR) in dir_link.  */
  43
  44   err = __file_getlinknode (oldfile, &linknode);
  45   __mach_port_deallocate (__mach_task_self (), oldfile);
  46   if (err)
  47     return __hurd_fail (err);
  48
  49   todir = __file_name_split_at (tofd, to, &toname);
  50   if (todir != MACH_PORT_NULL)
  51     {
  52       err = __dir_link (todir, linknode, toname, 1);
  53       __mach_port_deallocate (__mach_task_self (), todir);
  54     }
  55   __mach_port_deallocate (__mach_task_self (), linknode);
  56   if (todir == MACH_PORT_NULL)
  57     return -1;
  58
  59   if (err)
  60     return __hurd_fail (err);
  61   return 0;
  62 }