[Patch, libgfortran] READ from the terminal is broken - 2nd patch - urgent review, please.

[Thomas Koenig]

On Wed, Oct 12, 2005 at 07:17:28PM +0300, Janne Blomqvist wrote:

> No, not really. Your patch still touches fd_seek(). Attached patch is
> my proposal for a fix.
 
Is this really necessary?  This breaks one of the aims of your
original patch, which was to provide >2GB- records on 64-bit
systems.

If possible, I would prefer the following patch.  This only uses
a single read() for special files (like terminals) and do_read()
otherwise.

This is regression-tested on i686-pc-linux-gnu.  I would appreciate
if somebody could test it on a BSD-derived system to see that this
does fix the original problem.

Adding a test case for this bug will be ... interesting, requiring
integration of Dejagnu and pseudo terminals.  Ugh.  I hope everybody
agrees that we should waive the need for a test case here.

	Thomas
-------------- next part --------------
Index: unix.c
===================================================================
RCS file: /cvs/gcc/gcc/libgfortran/io/unix.c,v
retrieving revision 1.43
diff -c -p -r1.43 unix.c
*** unix.c	7 Oct 2005 20:02:28 -0000	1.43
--- unix.c	12 Oct 2005 21:46:38 -0000
*************** static char *
*** 440,446 ****
  fd_alloc_r_at (unix_stream * s, int *len, gfc_offset where)
  {
    gfc_offset m;
-   size_t n;
  
    if (where == -1)
      where = s->logical_offset;
--- 440,445 ----
*************** fd_alloc_r_at (unix_stream * s, int *len
*** 462,474 ****
    if (s->physical_offset != m && lseek (s->fd, m, SEEK_SET) < 0)
      return NULL;
  
!   n = s->len - s->active;
!   if (do_read (s, s->buffer + s->active, &n) != 0)
!     return NULL;
  
!   s->physical_offset = where + n;
  
-   s->active += n;
    if (s->active < *len)
      *len = s->active;		/* Bytes actually available */
  
--- 461,489 ----
    if (s->physical_offset != m && lseek (s->fd, m, SEEK_SET) < 0)
      return NULL;
  
!   if (s->special_file)
!     {
!       int n;
! 
!       n = s->len - s->active;
!       n = read (s->fd, s->buffer + s->active, s->len - s->active);
!       if (n < 0)
! 	return NULL;
! 
!       s->physical_offset = where + n;
!       s->active += n;
!     }
!   else
!     {
!       size_t n;
!       n = s->len - s->active;
!       if (do_read (s, s->buffer + s->active, &n) != 0)
! 	return NULL;
  
!       s->physical_offset = where + n;
!       s->active += n;
!     }
  
    if (s->active < *len)
      *len = s->active;		/* Bytes actually available */