compiler/clib/fdopen.c

   1 /*
   2     Copyright © 1995-2007, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     POSIX function fdopen().
   6 */
   7
   8 #include "__arosc_privdata.h"
   9
  10 #include <stdlib.h>
  11 #include <fcntl.h>
  12 #include <errno.h>
  13
  14 #include <exec/lists.h>
  15 #include <proto/exec.h>
  16
  17 #include "__stdio.h"
  18 #include "__open.h"
  19
  20 /*****************************************************************************
  21
  22     NAME */
  23 #include <stdio.h>
  24
  25         FILE *fdopen (
  26
  27 /*  SYNOPSIS */
  28         int         filedes,
  29         const char *mode
  30         )
  31
  32 /*  FUNCTION
  33         function associates a stream with an existing file descriptor.
  34
  35     INPUTS
  36         filedes - The descriptor the stream has to be associated with
  37         mode    - The mode of the stream  (same as with fopen()) must be com
  38                   patible with the mode of the file  descriptor.   The  file
  39                   position  indicator  of  the  new  stream  is  set to that
  40                   belonging to fildes, and the error and end-of-file indica
  41                   tors  are cleared.  Modes "w" or "w+" do not cause trunca
  42                   tion of the file.  The file descriptor is not dup'ed,  and
  43                   will  be  closed  when  the  stream  created  by fdopen is
  44                   closed.
  45
  46     RESULT
  47         NULL on error or the new stream assiciated with the descriptor.
  48
  49         The new descriptor returned by the call is the lowest numbered
  50         descriptor currently not in use by the process.
  51
  52     NOTES
  53         This function must not be used in a shared library or
  54         in a threaded application.
  55
  56     EXAMPLE
  57
  58     BUGS
  59
  60     SEE ALSO
  61          open(), fclose(), fileno()
  62
  63     INTERNALS
  64
  65 ******************************************************************************/
  66 {
  67     int oflags, wanted_accmode, current_accmode;
  68     fdesc *fdesc;
  69     FILENODE *fn;
  70
  71     if (!(fdesc = __getfdesc(filedes)))
  72     {
  73         errno = EBADF;
  74         return NULL;
  75     }
  76
  77     oflags = fdesc->flags;
  78
  79     if (mode)
  80     {
  81         oflags          = __smode2oflags(mode);
  82
  83         wanted_accmode  = oflags & O_ACCMODE;
  84         current_accmode = fdesc->flags & O_ACCMODE;
  85
  86         /*
  87            Check if the requested access mode flags are a valid subset of the
  88            flags of the already open file has. Thus, if the files access mode
  89            is O_RDWR the requested mode can be anything (O_RDONLY, O_WRONLY or
  90            O_RDWR), else they must match exactly.
  91         */
  92
  93         if ((current_accmode != O_RDWR) && (wanted_accmode != current_accmode))
  94         {
  95             errno = EINVAL;
  96             return NULL;
  97         }
  98     }
  99
 100     fn = malloc(sizeof(FILENODE));
 101     if (!fn) return NULL;
 102
 103     AddTail ((struct List *)&__stdio_files, (struct Node *)fn);
 104
 105     fn->File.flags = __oflags2sflags(oflags);
 106     fn->File.fd    = filedes;
 107
 108     return FILENODE2FILE(fn);
 109 }