usr/src/lib/libbc/libc/stdio/common/fdopen.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright 1989 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1984 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"  /* from S5R2 1.4 */
  31
  32 /*LINTLIBRARY*/
  33 /*
  34  * Unix routine to do an "fopen" on file descriptor
  35  * The mode has to be repeated because you can't query its
  36  * status
  37  */
  38
  39 #include <stdio.h>
  40 #include <sys/errno.h>
  41
  42 extern int  errno;
  43 extern long lseek();
  44 extern FILE *_findiop();
  45
  46 FILE *
  47 fdopen(fd, mode)
  48 int     fd;
  49 register char *mode;
  50 {
  51         static int nofile = -1;
  52         register FILE *iop;
  53
  54         if(nofile < 0)
  55                 nofile = getdtablesize();
  56
  57         if(fd < 0 || fd >= nofile) {
  58                 errno = EINVAL;
  59                 return(NULL);
  60         }
  61
  62         if((iop = _findiop()) == NULL)
  63                 return(NULL);
  64
  65         iop->_cnt = 0;
  66         iop->_file = fd;
  67         iop->_base = iop->_ptr = NULL;
  68         iop->_bufsiz = 0;
  69         switch(*mode) {
  70
  71                 case 'r':
  72                         iop->_flag = _IOREAD;
  73                         break;
  74                 case 'a':
  75                         (void) lseek(fd, 0L, 2);
  76                         /* No break */
  77                 case 'w':
  78                         iop->_flag = _IOWRT;
  79                         break;
  80                 default:
  81                         errno = EINVAL;
  82                         return(NULL);
  83         }
  84
  85         if(mode[1] == '+')
  86                 iop->_flag = _IORW;
  87
  88         return(iop);
  89 }