1  /* Create a symbolic link named relative to an open directory.  Hurd version.
       2     Copyright (C) 1991-2023 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     <https://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/paths.h>
      25  #include <hurd/fd.h>
      26  #include <string.h>
      27  
      28  
      29  /* Make a link to FROM called TO relative to FD.  */
      30  int
      31  __symlinkat (const char *from, int fd, const char *to)
      32  {
      33    error_t err;
      34    file_t dir, node;
      35    char *name;
      36    const size_t len = strlen (from) + 1;
      37    char buf[sizeof (_HURD_SYMLINK) + len];
      38  
      39    /* A symlink is a file whose translator is "/hurd/symlink\0target\0".  */
      40  
      41    memcpy (buf, _HURD_SYMLINK, sizeof (_HURD_SYMLINK));
      42    memcpy (&buf[sizeof (_HURD_SYMLINK)], from, len);
      43  
      44    dir = __file_name_split_at (fd, to, &name);
      45    if (dir == MACH_PORT_NULL)
      46      return -1;
      47  
      48    /* Create a new, unlinked node in the target directory.  */
      49    err = __dir_mkfile (dir, O_WRITE, 0777 & ~_hurd_umask, &node);
      50  
      51    if (! err)
      52      {
      53        /* Set the node's translator to make it a symlink.  */
      54        err = __file_set_translator (node,
      55                                     FS_TRANS_EXCL|FS_TRANS_SET,
      56                                     FS_TRANS_EXCL|FS_TRANS_SET, 0,
      57                                     buf, sizeof (_HURD_SYMLINK) + len,
      58                                     MACH_PORT_NULL, MACH_MSG_TYPE_COPY_SEND);
      59  
      60        if (! err)
      61          /* Link the node, now a valid symlink, into the target directory.  */
      62          err = __dir_link (dir, node, name, 1);
      63  
      64        __mach_port_deallocate (__mach_task_self (), node);
      65      }
      66  
      67    __mach_port_deallocate (__mach_task_self (), dir);
      68  
      69    if (err)
      70      return __hurd_fail (err);
      71    return 0;
      72  }
      73  
      74  weak_alias (__symlinkat, symlinkat)