getsockopt.c

来自「glibc 库, 不仅可以学习使用库函数,还可以学习函数的具体实现,是提高功力的」· C语言 代码 · 共 57 行

/* Copyright (C) 1992,94,97,2001,02 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 Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <errno.h>
#include <sys/socket.h>
#include <hurd.h>
#include <hurd/fd.h>
#include <hurd/socket.h>
#include <string.h>

/* Put the current value for socket FD's option OPTNAME at protocol level LEVEL
   into OPTVAL (which is *OPTLEN bytes long), and set *OPTLEN to the value's
   actual length.  Returns 0 on success, -1 for errors.  */

/* XXX should be __getsockopt ? */
int
getsockopt (int fd,
	    int level,
	    int optname,
	    void *optval,
	    socklen_t *optlen)
{
  error_t err;
  char *buf = optval;
  mach_msg_type_number_t buflen = *optlen;

  if (err = HURD_DPORT_USE (fd, __socket_getopt (port,
						 level, optname,
						 &buf, &buflen)))
    return __hurd_dfail (fd, err);

  if (*optlen > buflen)
    *optlen = buflen;
  if (buf != optval)
    {
      memcpy (optval, buf, *optlen);
      __vm_deallocate (__mach_task_self (), (vm_address_t) buf, buflen);
    }

  return 0;
}