Re: dd bug

[Buciuman Adrian]

  Sorry for my silence but I  really don't know . I'm not living  at home
during the school year . I have'n been able to test it here. I will be back
home in July , so I may try then.

  Anyone with a floppydisk / harddisk with bad sectors can try to reproduce
the bug and then try the patch . But is seems that defective
hardisk/floppydisks  are not easy to find this days.


----- Original Message -----
From: "Jim Meyering" <address@hidden>


> I don't seem to have ever received feedback about this patch.
> Did it solve the problem?
>
> Paul Eggert <address@hidden> wrote:
> > Buciuman Adrian <address@hidden> writes:
> >
> >> With the patch applied :  sectors 1-72 from the floppy , (1368+1440) *
512
> >> bytes of null padding ,
> >> sectors 1441 - 2880 from the floppy .
> >>
> >> ( sector 73 was bad )
> >>
> >> Therefore there is still 1 block of null paddding in excess.
> >
> > Thanks for debugging it further.  Can you please try this patch instead?
> > It supersedes my September 24 patch.
> >
> > 2003-10-12  Paul Eggert  <address@hidden>
> >
> > Fix bug reported by Buciuman Adrian in
> > <http://mail.gnu.org/archive/html/bug-coreutils/2003-08/msg00105.html>
> > where 'dd' created a file that was too large.  The bug was that dd
> > assumed that the input file offset does not advance after a failed
> > read; but POSIX says that the input file offset is undefined after
> > a failed read.
> >
> > * src/dd.c (MAX_BLOCKSIZE): New macro.
> > (input_seekable, input_seek_errno, input_offset,
> > input_offset_overflow): New vars.
> > (write_output, dd_copy): Pass EXIT_FAILURE to quit, not 1.
> > (scanargs): Reject block sizes greater than MAX_BLOCKSIZE>
> > (advance_input_offset): New function.
> > (skip_via_lseek): Set errno to zero when reporting our failure,
> > so that we don't report based on garbage errno.
> > (skip): If fdesc is standard input, advance the input offset.
> > Do not quit if reading, and if noerror was specified;
> > POSIX seems to require this.
> > If read fails on output file, report the earlier lseek failure
> > instead; this fixes a FIXME in dd_copy.
> > (advance_input_after_read_error): New function.
> > (dd_copy): Use it, instead of assuming that failed reads
> > do not advance the file pointer.  Advance input offset
> > after nonfailed reads.  Advance only a partial block if
> > the previous read (before the failed read) succeeded, and
> > do not generate an output block of zeros in this case.
> > (main): Determine initial input offset, seekability of input,
> > and error if it wasn't seekable.
>