/* $OpenBSD: atomicio.c,v 1.17 2006/04/01 05:51:34 djm Exp $ */

/*

 * Copied from OpenSSH/OpenBSD.

 * 

 * Copyright (c) 2005 Anil Madhavapeddy. All rights reserved.

 * Copyright (c) 1995,1999 Theo de Raadt.  All rights reserved.

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#include "includes.h"

#include "atomicio.h"

/*

 * ensure all of data on socket comes through. f==read || f==vwrite

 */

size_t

atomicio(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n)

{

  char *s = _s;

  size_t pos = 0;

  ssize_t res;

  while (n > pos) {

    res = (f) (fd, s + pos, n - pos);

    switch (res) {

    case -1:

      if (errno == EINTR || errno == EAGAIN)

        continue;

      return 0;

    case 0:

      errno = EPIPE;

      return pos;

    default:

      pos += (size_t)res;

    }

  }

  return (pos);

}