From: Jerry DeLisle <jvdelisle@gcc.gnu.org>
Date: Tue, 26 Nov 2019 22:56:24 +0000 (+0000)
Subject: backport: re PR libfortran/92100 (Formatted stream IO irreproducible read with binary... 
X-Git-Tag: releases/gcc-9.3.0~353
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5b1a33584cf912cba70494df079bef7f92bbc442;p=thirdparty%2Fgcc.git

backport: re PR libfortran/92100 (Formatted stream IO irreproducible read with binary data in file)

2019-11-26  Jerry DeLisle  <jvdelisle@gcc.ngu.org>

        Backport from mainline
        PR fortran/92100
        io/transfer.c (data_transfer_init_worker): Use fbuf_reset
        instead of fbuf_flush before the seek. Note that fbuf_reset
        calls fbuf_flush and adjusts fbuf pointers.

        gfortran.dg/streamio_18.f90: New test.

From-SVN: r278740
---

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index c07ef85ce927..2ec93f884c79 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2019-11-26  Jerry DeLisle  <jvdelisle@gcc.ngu.org>
+
+	Backport from trunk
+	PR fortran/92100
+	gfortran.dg/streamio_18.f90: New test.
+
 2019-11-25  Thomas Koenig  <tkoenig@gcc.gnu.org>
 	Harald Anlauf <anlauf@gmx.de>
 
diff --git a/gcc/testsuite/gfortran.dg/streamio_18.f90 b/gcc/testsuite/gfortran.dg/streamio_18.f90
new file mode 100644
index 000000000000..ee36238ecfaa
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/streamio_18.f90
@@ -0,0 +1,23 @@
+! { dg-do run }
+! PR91200
+program foo
+  implicit none
+  integer fd
+  open(newunit=fd, file='test.dat', access='stream', form='formatted')
+  write(fd,'(A)') '$MeshFormat'
+  write(fd,'(A)') 'aabbccdd'
+  close(fd)
+  call readfile  ! Read test.dat
+contains
+  subroutine readfile
+     character(len=20) buf1, buf2
+     integer fd, m, n
+     open(newunit=fd, file='test.dat', access='stream', form='formatted')
+     inquire(fd, pos=m)
+     if (m /= 1) stop 'm /= 1'
+     read(fd, *) buf1
+     read(fd, *, pos=m) buf2        ! Reread by using pos=1
+     close(fd, status='delete')
+     if (buf1 /= buf2) stop 'wrong'
+  end subroutine readfile
+end program
diff --git a/libgfortran/ChangeLog b/libgfortran/ChangeLog
index 5bf3cc8340d2..34ca3548589f 100644
--- a/libgfortran/ChangeLog
+++ b/libgfortran/ChangeLog
@@ -1,3 +1,11 @@
+2019-11-26  Jerry DeLisle  <jvdelisle@gcc.ngu.org>
+
+        Backport from mainline
+        PR fortran/92100
+        io/transfer.c (data_transfer_init_worker): Use fbuf_reset
+        instead of fbuf_flush before the seek. Note that fbuf_reset
+        calls fbuf_flush and adjusts fbuf pointers.
+
 2019-11-25  Thomas Koenig  <tkoenig@gcc.gnu.org>
 	Harald Anlauf <anlauf@gmx.de>
 
diff --git a/libgfortran/io/transfer.c b/libgfortran/io/transfer.c
index 8ed0391225d1..28e403fedf2f 100644
--- a/libgfortran/io/transfer.c
+++ b/libgfortran/io/transfer.c
@@ -3294,8 +3294,9 @@ data_transfer_init_worker (st_parameter_dt *dtp, int read_flag)
 
           if (dtp->pos != dtp->u.p.current_unit->strm_pos)
             {
-              fbuf_flush (dtp->u.p.current_unit, dtp->u.p.mode);
-              if (sseek (dtp->u.p.current_unit->s, dtp->pos - 1, SEEK_SET) < 0)
+              fbuf_reset (dtp->u.p.current_unit);
+              if (sseek (dtp->u.p.current_unit->s, dtp->pos - 1,
+		  SEEK_SET) < 0)
                 {
                   generate_error (&dtp->common, LIBERROR_OS, NULL);
                   return;