/* An interface to read and write that retries after interrupts.   Copyright (C) 1993, 1994, 1998, 2002 Free Software Foundation, Inc.   This program is free software; you can redistribute it and/or modify   it under the terms of the GNU General Public License as published by   the Free Software Foundation; either version 2, or (at your option)   any later version.   This program 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 General Public License for more details.   You should have received a copy of the GNU General Public License   along with this program; if not, write to the Free Software Foundation,   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */#if HAVE_CONFIG_H# include <config.h>#endif/* Get ssize_t.  */#include <sys/types.h>#if HAVE_UNISTD_H# include <unistd.h>#endif#include <errno.h>#ifndef errnoextern int errno;#endif#ifdef EINTR# define IS_EINTR(x) ((x) == EINTR)#else# define IS_EINTR(x) 0#endif#include <limits.h>#ifndef CHAR_BIT# define CHAR_BIT 8#endif/* The extra casts work around common compiler bugs.  */#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))/* The outer cast is needed to work around a bug in Cray C 5.0.3.0.   It is necessary at least when t == time_t.  */#define TYPE_MINIMUM(t) ((t) (TYPE_SIGNED (t) \			      ? ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1) : (t) 0))#define TYPE_MAXIMUM(t) ((t) (~ (t) 0 - TYPE_MINIMUM (t)))#ifndef INT_MAX# define INT_MAX TYPE_MAXIMUM (int)#endif#ifdef SAFE_WRITE# include "safe-write.h"# define safe_rw safe_write# define rw write#else# include "safe-read.h"# define safe_rw safe_read# define rw read# undef const# define const /* empty */#endif/* Read(write) up to COUNT bytes at BUF from(to) descriptor FD, retrying if   interrupted.  Return the actual number of bytes read(written), zero for EOF,   or SAFE_READ_ERROR(SAFE_WRITE_ERROR) upon error.  */size_tsafe_rw (int fd, void const *buf, size_t count){  ssize_t result;  /* POSIX limits COUNT to SSIZE_MAX, but we limit it further, requiring     that COUNT <= INT_MAX, to avoid triggering a bug in Tru64 5.1.     When decreasing COUNT, keep the file pointer block-aligned.     Note that in any case, read(write) may succeed, yet read(write)     fewer than COUNT bytes, so the caller must be prepared to handle     partial results.  */  if (count > INT_MAX)    count = INT_MAX & ~8191;  do    {      result = rw (fd, buf, count);    }  while (result < 0 && IS_EINTR (errno));  return (size_t) result;}