__symlink.c

来自「一个C源代码分析器」· C语言 代码 · 共 67 行

/* Copyright (C) 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
This file is part of the GNU C Library.

The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.

The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.  */

#include <ansidecl.h>
#include <string.h>
#include <unistd.h>
#include <hurd.h>
#include <hurd/paths.h>
#include <fcntl.h>

/* Make a link to FROM called TO.  */
int
DEFUN(__symlink, (from, to), CONST char *from AND CONST char *to)
{
  error_t err;
  file_t dir, node;
  char *name;
  const size_t len = strlen (from) + 1;
  char buf[sizeof (_HURD_SYMLINK) + len];

  /* A symlink is a file whose translator is "/hurd/symlink\0target\0".  */

  memcpy (buf, _HURD_SYMLINK, sizeof (_HURD_SYMLINK));
  memcpy (&buf[sizeof (_HURD_SYMLINK)], from, len);

  dir = __file_name_split (to, &name);
  if (dir == MACH_PORT_NULL)
    return -1;

  /* Create a new, unlinked node in the target directory.  */
  err = __dir_mkfile (dir, O_WRITE, 0777 & ~_hurd_umask, &node);

  if (! err)
    /* Set the node's translator to make it a symlink.  */
    err = __file_set_translator (node, 
				 FS_TRANS_EXCL|FS_TRANS_SET, 
				 FS_TRANS_EXCL|FS_TRANS_SET, 0,
				 buf, sizeof (_HURD_SYMLINK) + len,
				 MACH_PORT_NULL, MACH_MSG_TYPE_COPY_SEND);

  if (! err)
    /* Link the node, now a valid symlink, into the target directory.  */
    err = __dir_link (node, dir, name);

  __mach_port_deallocate (__mach_task_self (), dir);
  __mach_port_deallocate (__mach_task_self (), node);

  if (err)
    return __hurd_fail (err);
  return 0;
}