src/dragonfly/atomicio.c

   1 /* $OpenBSD: atomicio.c,v 1.7 2005/05/26 01:01:08 avsm Exp $ */
   2
   3 /*
   4  * Copyright (c) 2005 Anil Madhavapeddy.  All rights served.
   5  * Copyright (c) 1995,1999 Theo de Raadt.  All rights reserved.
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #include <sys/types.h>
  30 #include <sys/uio.h>
  31 #include <errno.h>
  32 #include <unistd.h>
  33 #include "atomicio.h"
  34
  35 /*
  36  * ensure all of data on socket comes through. f==read || f==vwrite
  37  */
  38 size_t
  39 atomicio(f, fd, _s, n)
  40         ssize_t (*f) (int, void *, size_t);
  41         int fd;
  42         void *_s;
  43         size_t n;
  44 {
  45         char *s = _s;
  46         size_t pos = 0;
  47         ssize_t res;
  48
  49         while (n > pos) {
  50                 res = (f) (fd, s + pos, n - pos);
  51                 switch (res) {
  52                 case -1:
  53                         if (errno == EINTR || errno == EAGAIN)
  54                                 continue;
  55                         return 0;
  56                 case 0:
  57                         errno = EPIPE;
  58                         return pos;
  59                 default:
  60                         pos += (u_int)res;
  61                 }
  62         }
  63         return pos;
  64 }