__mknod.c

来自「一个C源代码分析器」· C语言 代码 · 共 112 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 <errno.h>
#include <sys/stat.h>
#include <hurd.h>
#include <hurd/paths.h>
#include <fcntl.h>
#include "stdio/_itoa.h"

/* Temporary hack; this belongs in a header file, probably types.h. */
#define major(x) ((int)(((unsigned) (x) >> 8) & 0xff))
#define minor(x) ((int)((x) & 0xff))


/* Create a device file named FILE_NAME, with permission and special bits MODE
   and device number DEV (which can be constructed from major and minor
   device numbers with the `makedev' macro above).  */
int
DEFUN(__mknod, (file_name, mode, dev),
      CONST char *file_name AND mode_t mode AND dev_t dev)
{
  error_t err;
  file_t dir, node;
  char *name;
  char buf[100], *bp;
  const char *translator;
  size_t len;

  if (S_ISCHR (mode))
    {
      translator = _HURD_CHRDEV;
      len = sizeof (_HURD_CHRDEV);
    }
  else if (S_ISBLK (mode))
    {
      translator = _HURD_BLKDEV;
      len = sizeof (_HURD_BLKDEV);
    }
  else if (S_ISFIFO (mode))
    {
      translator = _HURD_FIFO;
      len = sizeof (_HURD_FIFO);
    }
  else
    {
      errno = EINVAL;
      return -1;
    }
  
  if (! S_ISFIFO (mode))
    {
      /* We set the translator to "ifmt\0major\0minor\0", where IFMT
	 depends on the S_IFMT bits of our MODE argument, and MAJOR and
	 MINOR are ASCII decimal (octal or hex would do as well)
	 representations of our arguments.  Thus the convention is that
	 CHRDEV and BLKDEV translators are invoked with two non-switch
	 arguments, giving the major and minor device numbers in %i format. */

      bp = buf + sizeof (buf);
      *--bp = '\0';
      bp = _itoa (minor (dev), bp, 10, 0);
      *--bp = '\0';
      bp = _itoa (major (dev), bp, 10, 0);
      memcpy (bp - len, translator, len);
      translator = bp - len;
      len = buf + sizeof (buf) - translator;
    }
  
  dir = __file_name_split (file_name, &name);
  if (dir == MACH_PORT_NULL)
    return -1;

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

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

  if (! err)
    /* Link the node, now a valid device, 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;
}