text: /* crypto/bio/bss_fd.c */
  /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   * All rights reserved.
   *
   * This package is an SSL implementation written
   * by Eric Young (eay@cryptsoft.com).
   * The implementation was written so as to conform with Netscapes SSL.
   * 
   * This library is free for commercial and non-commercial use as long as
   * the following conditions are aheared to.  The following conditions
   * apply to all code found in this distribution, be it the RC4, RSA,
   * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
   * included with this distribution is covered by the same copyright terms
   * except that the holder is Tim Hudson (tjh@cryptsoft.com).
   * 
   * Copyright remains Eric Young's, and as such any Copyright notices in
   * the code are not to be removed.
   * If this package is used in a product, Eric Young should be given attribution
   * as the author of the parts of the library used.
   * This can be in the form of a textual message at program startup or
   * in documentation (online or textual) provided with the package.
   * 
   * 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 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.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *    "This product includes cryptographic software written by
   *     Eric Young (eay@cryptsoft.com)"
   *    The word 'cryptographic' can be left out if the rouines from the library
   *    being used are not cryptographic related :-).
   * 4. If you include any Windows specific code (or a derivative thereof) from 
   *    the apps directory (application code) you must include an acknowledgement:
   *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
   * 
   * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``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 OR CONTRIBUTORS 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.
   * 
   * The licence and distribution terms for any publically available version or
   * derivative of this code cannot be changed.  i.e. this code cannot simply be
   * copied and put under another distribution licence
   * [including the GNU Public Licence.]
   */
  
  #include <stdio.h>
  #include <errno.h>
  #define USE_SOCKETS
  #include "cryptlib.h"
  
  #if defined(OPENSSL_NO_POSIX_IO)
  /*
   * One can argue that one should implement dummy placeholder for
   * BIO_s_fd here...
   */
  #else
  /*
   * As for unconditional usage of "UPLINK" interface in this module.
   * Trouble is that unlike Unix file descriptors [which are indexes
   * in kernel-side per-process table], corresponding descriptors on
   * platforms which require "UPLINK" interface seem to be indexes
   * in a user-land, non-global table. Well, in fact they are indexes
   * in stdio _iob[], and recall that _iob[] was the very reason why
   * "UPLINK" interface was introduced in first place. But one way on
   * another. Neither libcrypto or libssl use this BIO meaning that
   * file descriptors can only be provided by application. Therefore
   * "UPLINK" calls are due...
   */
  #include "bio_lcl.h"
  
  static int fd_write(BIO *h, const char *buf, int num);
  static int fd_read(BIO *h, char *buf, int size);
  static int fd_puts(BIO *h, const char *str);
  static int fd_gets(BIO *h, char *buf, int size);
  static long fd_ctrl(BIO *h, int cmd, long arg1, void *arg2);
  static int fd_new(BIO *h);
  static int fd_free(BIO *data);
  int BIO_fd_should_retry(int s);
  
  static BIO_METHOD methods_fdp=
  	{
  	BIO_TYPE_FD,"file descriptor",
  	fd_write,
  	fd_read,
  	fd_puts,
  	fd_gets,
  	fd_ctrl,
  	fd_new,
  	fd_free,
  	NULL,
  	};
  
  BIO_METHOD *BIO_s_fd(void)
  	{
  	return(&methods_fdp);
  	}
  
  BIO *BIO_new_fd(int fd,int close_flag)
  	{
  	BIO *ret;
  	ret=BIO_new(BIO_s_fd());
  	if (ret == NULL) return(NULL);
  	BIO_set_fd(ret,fd,close_flag);
  	return(ret);
  	}
  
  static int fd_new(BIO *bi)
  	{
  	bi->init=0;
  	bi->num=-1;
  	bi->ptr=NULL;
  	bi->flags=BIO_FLAGS_UPLINK; /* essentially redundant */
  	return(1);
  	}
  
  static int fd_free(BIO *a)
  	{
  	if (a == NULL) return(0);
  	if (a->shutdown)
  		{
  		if (a->init)
  			{
  			UP_close(a->num);
  			}
  		a->init=0;
  		a->flags=BIO_FLAGS_UPLINK;
  		}
  	return(1);
  	}
  	
  static int fd_read(BIO *b, char *out,int outl)
  	{
  	int ret=0;
  
  	if (out != NULL)
  		{
  		clear_sys_error();
  		ret=UP_read(b->num,out,outl);
  		BIO_clear_retry_flags(b);
  		if (ret <= 0)
  			{
  			if (BIO_fd_should_retry(ret))
  				BIO_set_retry_read(b);
  			}
  		}
  	return(ret);
  	}
  
  static int fd_write(BIO *b, const char *in, int inl)
  	{
  	int ret;
  	clear_sys_error();
  	ret=UP_write(b->num,in,inl);
  	BIO_clear_retry_flags(b);
  	if (ret <= 0)
  		{
  		if (BIO_fd_should_retry(ret))
  			BIO_set_retry_write(b);
  		}
  	return(ret);
  	}
  
  static long fd_ctrl(BIO *b, int cmd, long num, void *ptr)
  	{
  	long ret=1;
  	int *ip;
  
  	switch (cmd)
  		{
  	case BIO_CTRL_RESET:
  		num=0;
  	case BIO_C_FILE_SEEK:
  		ret=(long)UP_lseek(b->num,num,0);
  		break;
  	case BIO_C_FILE_TELL:
  	case BIO_CTRL_INFO:
  		ret=(long)UP_lseek(b->num,0,1);
  		break;
  	case BIO_C_SET_FD:
  		fd_free(b);
  		b->num= *((int *)ptr);
  		b->shutdown=(int)num;
  		b->init=1;
  		break;
  	case BIO_C_GET_FD:
  		if (b->init)
  			{
  			ip=(int *)ptr;
  			if (ip != NULL) *ip=b->num;
  			ret=b->num;
  			}
  		else
  			ret= -1;
  		break;
  	case BIO_CTRL_GET_CLOSE:
  		ret=b->shutdown;
  		break;
  	case BIO_CTRL_SET_CLOSE:
  		b->shutdown=(int)num;
  		break;
  	case BIO_CTRL_PENDING:
  	case BIO_CTRL_WPENDING:
  		ret=0;
  		break;
  	case BIO_CTRL_DUP:
  	case BIO_CTRL_FLUSH:
  		ret=1;
  		break;
  	default:
  		ret=0;
  		break;
  		}
  	return(ret);
  	}
  
  static int fd_puts(BIO *bp, const char *str)
  	{
  	int n,ret;
  
  	n=strlen(str);
  	ret=fd_write(bp,str,n);
  	return(ret);
  	}
  
  static int fd_gets(BIO *bp, char *buf, int size)
          {
  	int ret=0;
  	char *ptr=buf;
  	char *end=buf+size-1;
  
  	while ( (ptr < end) && (fd_read(bp, ptr, 1) > 0) && (ptr[0] != '\n') )
  		ptr++;
  
  	ptr[0]='\0';
  
  	if (buf[0] != '\0')
  		ret=strlen(buf);
  	return(ret);
          }
  
  int BIO_fd_should_retry(int i)
  	{
  	int err;
  
  	if ((i == 0) || (i == -1))
  		{
  		err=get_last_sys_error();
  
  #if defined(OPENSSL_SYS_WINDOWS) && 0 /* more microsoft stupidity? perhaps not? Ben 4/1/99 */
  		if ((i == -1) && (err == 0))
  			return(1);
  #endif
  
  		return(BIO_fd_non_fatal_error(err));
  		}
  	return(0);
  	}
  
  int BIO_fd_non_fatal_error(int err)
  	{
  	switch (err)
  		{
  
  #ifdef EWOULDBLOCK
  # ifdef WSAEWOULDBLOCK
  #  if WSAEWOULDBLOCK != EWOULDBLOCK
  	case EWOULDBLOCK:
  #  endif
  # else
  	case EWOULDBLOCK:
  # endif
  #endif
  
  #if defined(ENOTCONN)
  	case ENOTCONN:
  #endif
  
  #ifdef EINTR
  	case EINTR:
  #endif
  
  #ifdef EAGAIN
  #if EWOULDBLOCK != EAGAIN
  	case EAGAIN:
  # endif
  #endif
  
  #ifdef EPROTO
  	case EPROTO:
  #endif
  
  #ifdef EINPROGRESS
  	case EINPROGRESS:
  #endif
  
  #ifdef EALREADY
  	case EALREADY:
  #endif
  		return(1);
  		/* break; */
  	default:
  		break;
  		}
  	return(0);
  	}
  #endif
  