sysdeps/mach/hurd/linkat.c

   1 /* Make a link between file names relative to open directories.  Hurd version.
   2    Copyright (C) 2006,2010 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 (fromfd, from, tofd, to, flags)
  30      int fromfd;
  31      const char *from;
  32      int tofd;
  33      const char *to;
  34      int flags;
  35 {
  36   error_t err;
  37   file_t oldfile, linknode, todir;
  38   char *toname;
  39
  40   /* POSIX says linkat doesn't follow symlinks by default, so pass
  41      O_NOLINK.  That can be overridden by AT_SYMLINK_FOLLOW in FLAGS.  */
  42   oldfile = __file_name_lookup_at (fromfd, flags, from, O_NOLINK, 0);
  43   if (oldfile == MACH_PORT_NULL)
  44     return -1;
  45
  46   /* The file_getlinknode RPC returns the port that should be passed to
  47      the receiving filesystem (the one containing TODIR) in dir_link.  */
  48
  49   err = __file_getlinknode (oldfile, &linknode);
  50   __mach_port_deallocate (__mach_task_self (), oldfile);
  51   if (err)
  52     return __hurd_fail (err);
  53
  54   todir = __file_name_split_at (tofd, to, &toname);
  55   if (todir != MACH_PORT_NULL)
  56     {
  57       err = __dir_link (todir, linknode, toname, 1);
  58       __mach_port_deallocate (__mach_task_self (), todir);
  59     }
  60   __mach_port_deallocate (__mach_task_self (), linknode);
  61   if (todir == MACH_PORT_NULL)
  62     return -1;
  63
  64   if (err)
  65     return __hurd_fail (err);
  66   return 0;
  67 }