sysdeps/mach/hurd/symlink.c

   1 /* Copyright (C) 1991-2016 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <string.h>
  19 #include <unistd.h>
  20 #include <hurd.h>
  21 #include <hurd/paths.h>
  22 #include <fcntl.h>
  23
  24 /* Make a link to FROM called TO.  */
  25 int
  26 __symlink (const char *from, const char *to)
  27 {
  28   error_t err;
  29   file_t dir, node;
  30   char *name;
  31   const size_t len = strlen (from) + 1;
  32   char buf[sizeof (_HURD_SYMLINK) + len];
  33
  34   /* A symlink is a file whose translator is "/hurd/symlink\0target\0".  */
  35
  36   memcpy (buf, _HURD_SYMLINK, sizeof (_HURD_SYMLINK));
  37   memcpy (&buf[sizeof (_HURD_SYMLINK)], from, len);
  38
  39   dir = __file_name_split (to, &name);
  40   if (dir == MACH_PORT_NULL)
  41     return -1;
  42
  43   /* Create a new, unlinked node in the target directory.  */
  44   err = __dir_mkfile (dir, O_WRITE, 0777 & ~_hurd_umask, &node);
  45
  46   if (! err)
  47     {
  48       /* Set the node's translator to make it a symlink.  */
  49       err = __file_set_translator (node,
  50                                    FS_TRANS_EXCL|FS_TRANS_SET,
  51                                    FS_TRANS_EXCL|FS_TRANS_SET, 0,
  52                                    buf, sizeof (_HURD_SYMLINK) + len,
  53                                    MACH_PORT_NULL, MACH_MSG_TYPE_COPY_SEND);
  54
  55       if (! err)
  56         /* Link the node, now a valid symlink, into the target directory.  */
  57         err = __dir_link (dir, node, name, 1);
  58
  59       __mach_port_deallocate (__mach_task_self (), node);
  60     }
  61
  62   __mach_port_deallocate (__mach_task_self (), dir);
  63
  64   if (err)
  65     return __hurd_fail (err);
  66   return 0;
  67 }
  68
  69 weak_alias (__symlink, symlink)