binutils-gdb/gdb/testsuite/lib/unbuffer_output.c
Pedro Alves 6f98576f29 Add "../lib/unbuffer_output.c" and use it in gdb.base/interrupt.c
In some scenarios, GDB or GDBserver can be spawned with input _not_
connected to a tty, and then tests that rely on stdio fail with
timeouts, because the inferior's stdout and stderr streams end up
fully buffered.

See discussion here:
  https://sourceware.org/ml/gdb-patches/2015-02/msg00809.html

We have a hack in place that works around this for Windows testing,
that forces every test program to link with an .o file that does
(lib/set_unbuffered_mode.c):

 static int __gdb_set_unbuffered_output (void) __attribute__ ((constructor));
 static int
 __gdb_set_unbuffered_output (void)
 {
   setvbuf (stdout, NULL, _IONBF, BUFSIZ);
   setvbuf (stderr, NULL, _IONBF, BUFSIZ);
 }

That's a bit hacky; it ends up done for _all_ tests.

This patch adds a way to do this unbuffering explicitly from the test
code itself, so it is done only when necessary, and for all
targets/hosts.  For starters, it adjusts gdb.base/interrupt.c to use
it.

Tested on x86_64 Fedora 20, native, and against a remote gdbserver
board file that connects to the target with ssh, with and without -t
(create pty).

gdb/testsuite/
2015-02-27  Pedro Alves  <palves@redhat.com>

	* lib/unbuffer_output.c: New file.
	* gdb.base/interrupt.c: Include "../lib/unbuffer_output.c".
	(main): Call gdb_unbuffer_output.
2015-02-27 13:54:22 +00:00

40 lines
1.3 KiB
C

/* Copyright (C) 2008-2015 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* Force output to unbuffered mode if not connected to a terminal. */
#include <stdio.h>
#ifndef __MINGW32__
#include <unistd.h>
#endif
static int
gdb_unbuffer_output (void)
{
/* Always force this for Windows testing. To a native Windows
program running under a Cygwin shell/ssh, stdin is really a
Windows pipe, thus not a tty and its outputs ends up fully
buffered. */
#ifndef __MINGW32__
if (!isatty (fileno (stdin)))
#endif
{
setvbuf (stdout, NULL, _IONBF, BUFSIZ);
setvbuf (stderr, NULL, _IONBF, BUFSIZ);
}
}