compiler/clib/fdopen.c

   1 /*
   2     Copyright © 1995-2003, 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     AROS_GET_SYSBASE_OK
  72
  73     if (!(fdesc = __getfdesc(filedes)))
  74     {
  75         errno = EBADF;
  76         return NULL;
  77     }
  78
  79     oflags = fdesc->flags;
  80
  81     if (mode)
  82     {
  83         oflags          = __smode2oflags(mode);
  84
  85         wanted_accmode  = oflags & O_ACCMODE;
  86         current_accmode = fdesc->flags & O_ACCMODE;
  87
  88         /*
  89            Check if the requested access mode flags are a valid subset of the
  90            flags of the already open file has. Thus, if the files access mode
  91            is O_RDWR the requested mode can be anything (O_RDONLY, O_WRONLY or
  92            O_RDWR), else they must match exactly.
  93         */
  94
  95         if ((current_accmode != O_RDWR) && (wanted_accmode != current_accmode))
  96         {
  97             errno = EINVAL;
  98             return NULL;
  99         }
 100     }
 101
 102     fn = malloc(sizeof(FILENODE));
 103     if (!fn) return NULL;
 104
 105     AddTail ((struct List *)&__stdio_files, (struct Node *)fn);
 106
 107     fn->File.flags = __oflags2sflags(oflags);
 108     fn->File.fd    = filedes;
 109
 110     return FILENODE2FILE(fn);
 111 }