[Bug libfortran/23321] New: Direct unformatted read beyond EOF cores

["bsp at kithrup dot com" <gcc-bugzilla@gcc.gnu.org>]

c  Summary: Direct unformatted read beyond EOF cores

c  This program demonstrates a bug in gfortran/libgfortran.
c  The bug is that a
c  program dumps core when reading beyond the end of
c  a access='direct', form='unformatted' file instead
c  of transfering control to 'err=' label.
c  Also, returns incorrectly when reading at end of file.

c  To test
c    dd if=/dev/zero of=shortfile bs=11811 count=1
c    ./a.out
c    Bus error (core dumped)
c    dd if=/dev/zero of=shortfile bs=11812 count=1
c    ./a.out
c    should not get here
c    before 779 inbuf(1)=   32
c    STOP 0

c    Note: in the above case, the value of inbuf(1) got set to a space

c  When compiled with ifort or g77, the correct output is produced
c  in both cases.
c    ./a.out
c    at 779, all is good

c  Problem occurs in
c    GNU Fortran 95 (GCC 4.0.1)
c    GNU Fortran 95 (GCC 4.0.2 20050804 (prerelease))
c    GNU Fortran 95 (GCC 4.1.0 20050806 (experimental))

c gfortran -v
c Using built-in specs.
c Target: i686-pc-linux-gnu
c Configured with: ../../NetSrc/gcc-4.1-20050806/configure --prefix=/home/bswift/afrl/
builddev/NetInst/gcc-4.1-20050806 --enable-languages=c,f95 --with-gmp=/home/bswift/afrl/
builddev/NetInst/gmp-4.1.4 --with-mpfr=/home/bswift/afrl/builddev/NetInst/mpfr-2.1.2
c Thread model: posix
c gcc version 4.1.0 20050806 (experimental)

      implicit none

      integer    nbytes

      integer inbuflen
      parameter (inbuflen=32768)
      integer*1      inbuf(inbuflen)
      integer k

      inbuf(1)=5

      nbytes=11812

      open(35,file='shortfile',access='direct',recl=nbytes,form
     $     ='unformatted')

      read(35,rec=2,err=779) (inbuf(k),k=1,nbytes)

      write(*,*) 'should not get here'
      write(*,*) 'before 779 inbuf(1)=',inbuf(1)
      stop
 779  write(*,*) 'at 779, all is good'
      end

-- 
           Summary: Direct unformatted read beyond EOF cores
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: libfortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: bsp at kithrup dot com
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23321