newlib/libc/stdio/fdopen.c

   1 /*
   2  * Copyright (c) 1990 The Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms are permitted
   6  * provided that the above copyright notice and this paragraph are
   7  * duplicated in all such forms and that any documentation,
   8  * and/or other materials related to such
   9  * distribution and use acknowledge that the software was developed
  10  * by the University of California, Berkeley.  The name of the
  11  * University may not be used to endorse or promote products derived
  12  * from this software without specific prior written permission.
  13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  15  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  16  */
  17
  18 /*
  19 FUNCTION
  20 <<fdopen>>---turn open file into a stream
  21
  22 INDEX
  23         fdopen
  24 INDEX
  25         _fdopen_r
  26
  27 SYNOPSIS
  28         #include <stdio.h>
  29         FILE *fdopen(int <[fd]>, const char *<[mode]>);
  30         FILE *_fdopen_r(struct _reent *<[reent]>,
  31                         int <[fd]>, const char *<[mode]>);
  32
  33 DESCRIPTION
  34 <<fdopen>> produces a file descriptor of type <<FILE *>>, from a
  35 descriptor for an already-open file (returned, for example, by the
  36 system subroutine <<open>> rather than by <<fopen>>).
  37 The <[mode]> argument has the same meanings as in <<fopen>>.
  38
  39 RETURNS
  40 File pointer or <<NULL>>, as for <<fopen>>.
  41
  42 PORTABILITY
  43 <<fdopen>> is ANSI.
  44 */
  45
  46 #include <_ansi.h>
  47 #include <reent.h>
  48 #include <sys/types.h>
  49 #include <sys/fcntl.h>
  50 #include <stdio.h>
  51 #include <errno.h>
  52 #include "local.h"
  53 #include <_syslist.h>
  54
  55 FILE *
  56 _fdopen_r (struct _reent *ptr,
  57        int fd,
  58        const char *mode)
  59 {
  60   register FILE *fp;
  61   int flags, oflags;
  62 #ifdef HAVE_FCNTL
  63   int fdflags, fdmode;
  64 #endif
  65
  66   if ((flags = __sflags (ptr, mode, &oflags)) == 0)
  67     return 0;
  68
  69   /* make sure the mode the user wants is a subset of the actual mode */
  70 #ifdef HAVE_FCNTL
  71   if ((fdflags = _fcntl_r (ptr, fd, F_GETFL, 0)) < 0)
  72     return 0;
  73   fdmode = fdflags & O_ACCMODE;
  74   if (fdmode != O_RDWR && (fdmode != (oflags & O_ACCMODE)))
  75     {
  76       _REENT_ERRNO(ptr) = EBADF;
  77       return 0;
  78     }
  79 #endif
  80
  81   if ((fp = __sfp (ptr)) == 0)
  82     return 0;
  83
  84   _newlib_flockfile_start (fp);
  85
  86   fp->_flags = flags;
  87   /* POSIX recommends setting the O_APPEND bit on fd to match append
  88      streams.  Someone may later clear O_APPEND on fileno(fp), but the
  89      stream must still remain in append mode.  Rely on __sflags
  90      setting __SAPP properly.  */
  91 #ifdef HAVE_FCNTL
  92   if ((oflags & O_APPEND) && !(fdflags & O_APPEND))
  93     _fcntl_r (ptr, fd, F_SETFL, fdflags | O_APPEND);
  94 #endif
  95   fp->_file = fd;
  96   fp->_cookie = (void *) fp;
  97
  98 #undef _read
  99 #undef _write
 100 #undef _seek
 101 #undef _close
 102
 103   fp->_read = __sread;
 104   fp->_write = __swrite;
 105   fp->_seek = __sseek;
 106   fp->_close = __sclose;
 107
 108 #ifdef __SCLE
 109   /* Explicit given mode results in explicit setting mode on fd */
 110   if (oflags & O_BINARY)
 111     setmode (fp->_file, O_BINARY);
 112   else if (oflags & O_TEXT)
 113     setmode (fp->_file, O_TEXT);
 114   if (__stextmode (fp->_file))
 115     fp->_flags |= __SCLE;
 116 #endif
 117
 118   _newlib_flockfile_end (fp);
 119   return fp;
 120 }
 121
 122 #ifndef _REENT_ONLY
 123
 124 FILE *
 125 fdopen (int fd,
 126        const char *mode)
 127 {
 128   return _fdopen_r (_REENT, fd, mode);
 129 }
 130
 131 #endif