[patch] for testsuite: "read1" reproducer (from PR 12649)

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

Hi,

as Doug suggested in:
	http://sourceware.org/ml/gdb-patches/2013-01/msg00675.html
	Message-ID: <CADPb22RjWDHncdgeBxbh5Ee+gKw1P6d8jEge9cMx_BzCbYh1iQ@mail.gmail.com>

going to check-in this - unfortunately still useful - reproducer currently at:
	http://sourceware.org/bugzilla/show_bug.cgi?id=12649


On Mon, 28 Jan 2013 19:16:17 +0100, Doug Evans wrote:
> An excellent thing to add to testsuite/contrib or some such, 

cc-with-tweaks.sh is also useful mostly only with the testsuite and it is in
gdb/contrib/ (and not in non-existing gdb/testsuite/contrib/).


For example gdb.cp/cpcompletion.exp works for me as a verification.
	PASS
->
	FAIL: gdb.cp/cpcompletion.exp: complete class methods (Foo not found)
	FAIL: gdb.cp/cpcompletion.exp: complete class methods beginning with F (Foo not found)


Thanks,
Jan


gdb/
2013-01-29  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* contrib/expect-read1.c: New file.
	* contrib/expect-read1.sh: New file.

diff --git a/gdb/contrib/expect-read1.c b/gdb/contrib/expect-read1.c
new file mode 100644
index 0000000..963c1ff
--- /dev/null
+++ b/gdb/contrib/expect-read1.c
@@ -0,0 +1,40 @@
+/* Copyright (C) 2013 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/>.  */
+
+/* RTLD_NEXT requires _GNU_SOURCE.  */
+#define _GNU_SOURCE 1
+#include <dlfcn.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdlib.h>
+
+ssize_t
+read (int fd, void *buf, size_t count)
+{
+  static ssize_t (*read2) (int fd, void *buf, size_t count) = NULL;
+
+  if (read2 == NULL)
+    {
+      unsetenv ("LD_PRELOAD");
+      read2 = dlsym (RTLD_NEXT, "read");
+    }
+
+  if (count > 1 && isatty (fd) == 1)
+    count = 1;
+
+  return read2 (fd, buf, count);
+}
diff --git a/gdb/contrib/expect-read1.sh b/gdb/contrib/expect-read1.sh
new file mode 100755
index 0000000..ad32520
--- /dev/null
+++ b/gdb/contrib/expect-read1.sh
@@ -0,0 +1,42 @@
+#! /bin/sh
+# runtest wrapper to reliably reproduce racy incomplete reads in the testsuite.
+
+# Copyright (C) 2013 Free Software Foundation, Inc.
+# 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/>.
+
+# This tool excercise any incomplete reads handling in the testsuite by
+# simulating read always returns just 1 character.
+# Testsuite incompatibilities are tracked as GDB PR testsuite/12649.
+
+# Example usage:
+#
+# bash$ cd $objdir/gdb/testsuite
+# bash$ EXPECT=$srcdir/gdb/contrib/expect-read1.sh runtest
+# or
+# bash$ EXPECT=../contrib/expect-read1.sh runtest
+
+C=`echo $0|sed 's/\.sh$/.c/'`
+if ! test -e $C; then
+  echo >&2 "$0: Cannot find 'srcdir/gdb/contrib/expect-read1.c' at '$C'."
+  exit 2
+fi
+SO=/tmp/expect-read1.$$.so
+rm -f $SO
+CMD="${CC_FOR_TARGET:-gcc} -o $SO -Wall -fPIC -shared $C"
+if ! $CMD; then
+  echo >&2 "$0: Failed: $CMD"
+  exit 2
+fi
+trap "rm -f $SO" EXIT
+LD_PRELOAD=$SO expect "$@"