sysdeps/mach/hurd/symlinkat.c

   1 /* Create a symbolic link named relative to an open directory.  Hurd version.
   2    Copyright (C) 1991,1992,1993,1994,1995,1996,1997,2006
   3         Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <errno.h>
  22 #include <fcntl.h>
  23 #include <stddef.h>
  24 #include <unistd.h>
  25 #include <hurd.h>
  26 #include <hurd/paths.h>
  27 #include <hurd/fd.h>
  28 #include <string.h>
  29
  30
  31 /* Make a link to FROM called TO relative to FD.  */
  32 int
  33 symlinkat (from, fd, to)
  34      const char *from;
  35      int fd;
  36      const char *to;
  37 {
  38   error_t err;
  39   file_t dir, node;
  40   char *name;
  41   const size_t len = strlen (from) + 1;
  42   char buf[sizeof (_HURD_SYMLINK) + len];
  43
  44   /* A symlink is a file whose translator is "/hurd/symlink\0target\0".  */
  45
  46   memcpy (buf, _HURD_SYMLINK, sizeof (_HURD_SYMLINK));
  47   memcpy (&buf[sizeof (_HURD_SYMLINK)], from, len);
  48
  49   dir = __file_name_split_at (fd, to, &name);
  50   if (dir == MACH_PORT_NULL)
  51     return -1;
  52
  53   /* Create a new, unlinked node in the target directory.  */
  54   err = __dir_mkfile (dir, O_WRITE, 0777 & ~_hurd_umask, &node);
  55
  56   if (! err)
  57     /* Set the node's translator to make it a symlink.  */
  58     err = __file_set_translator (node,
  59                                  FS_TRANS_EXCL|FS_TRANS_SET,
  60                                  FS_TRANS_EXCL|FS_TRANS_SET, 0,
  61                                  buf, sizeof (_HURD_SYMLINK) + len,
  62                                  MACH_PORT_NULL, MACH_MSG_TYPE_COPY_SEND);
  63
  64   if (! err)
  65     /* Link the node, now a valid symlink, into the target directory.  */
  66     err = __dir_link (dir, node, name, 1);
  67
  68   __mach_port_deallocate (__mach_task_self (), dir);
  69   __mach_port_deallocate (__mach_task_self (), node);
  70
  71   if (err)
  72     return __hurd_fail (err);
  73   return 0;
  74 }