stdio/FreeBSD/fdopen.c

   1 /*-
   2  * Copyright (c) 1990, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Chris Torek.
   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  * 4. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #ifdef VARIANT_DARWINEXTSN
  34 #define _DARWIN_UNLIMITED_STREAMS
  35 #define COUNT   0
  36 #elif defined(VARIANT_LEGACY)
  37 #define COUNT   0
  38 #else
  39 #define COUNT   1
  40 #endif
  41
  42 #if defined(LIBC_SCCS) && !defined(lint)
  43 static char sccsid[] = "@(#)fdopen.c    8.1 (Berkeley) 6/4/93";
  44 #endif /* LIBC_SCCS and not lint */
  45 #include <sys/cdefs.h>
  46 __FBSDID("$FreeBSD: src/lib/libc/stdio/fdopen.c,v 1.11 2008/05/10 18:39:20 antoine Exp $");
  47
  48 #include "namespace.h"
  49 #include <sys/types.h>
  50 #include <fcntl.h>
  51 #include <unistd.h>
  52 #include <stdio.h>
  53 #include <errno.h>
  54 #include <limits.h>
  55 #include "un-namespace.h"
  56 #include "local.h"
  57
  58 FILE *
  59 fdopen(fd, mode)
  60         int fd;
  61         const char *mode;
  62 {
  63         FILE *fp;
  64         int flags, oflags, fdflags, tmp;
  65
  66         /*
  67          * File descriptors are a full int, but _file is only a short.
  68          * If we get a valid file descriptor that is greater than
  69          * SHRT_MAX, then the fd will get sign-extended into an
  70          * invalid file descriptor.  Handle this case by failing the
  71          * open.
  72          */
  73         if (fd > SHRT_MAX) {
  74                 errno = EMFILE;
  75                 return (NULL);
  76         }
  77
  78         if ((flags = __sflags(mode, &oflags)) == 0)
  79                 return (NULL);
  80
  81         /* Make sure the mode the user wants is a subset of the actual mode. */
  82         if ((fdflags = _fcntl(fd, F_GETFL, 0)) < 0)
  83                 return (NULL);
  84         tmp = fdflags & O_ACCMODE;
  85         if (tmp != O_RDWR && (tmp != (oflags & O_ACCMODE))) {
  86                 errno = EINVAL;
  87                 return (NULL);
  88         }
  89
  90         if ((fp = __sfp(COUNT)) == NULL)
  91                 return (NULL);
  92         fp->_flags = flags;
  93         /*
  94          * If opened for appending, but underlying descriptor does not have
  95          * O_APPEND bit set, assert __SAPP so that __swrite() caller
  96          * will _sseek() to the end before write.
  97          */
  98         if ((oflags & O_APPEND) && !(fdflags & O_APPEND))
  99                 fp->_flags |= __SAPP;
 100         fp->_file = fd;
 101         fp->_cookie = fp;
 102         fp->_read = __sread;
 103         fp->_write = __swrite;
 104         fp->_seek = __sseek;
 105         fp->_close = __sclose;
 106         return (fp);
 107 }