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

[Paul Thomas]

Thomas,

I already committed Janne's proposed patch.  With that, I step aside in 
your favour.  I think that you are right to want to retain the original 
aim of the patch. I will leave it to you and Janne to sort out...

I also concluded that a testcase was, as some Japanese might say, 
"slightly impossible".  This is a pity but we can live with it.

Regards

Paul

>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
>  
>
>------------------------------------------------------------------------
>
>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 */
>  
>  
>