[PATCH 8/8] New test about step over clone syscall

[Yao Qi <qiyaoltc@gmail.com>]

This patch adds a new test for stepping over clone syscall.

2016-02-19  Yao Qi  <yao.qi@linaro.org>

	* gdb.base/step-over-syscall.exp (step_over_syscall): Kfail.
	Invoke step_over_syscall "clone".
	* gdb.base/step-over-clone.c: New file.
---
 gdb/testsuite/gdb.base/step-over-clone.c     | 53 ++++++++++++++++++++++++++++
 gdb/testsuite/gdb.base/step-over-syscall.exp | 17 +++++++++
 2 files changed, 70 insertions(+)
 create mode 100644 gdb/testsuite/gdb.base/step-over-clone.c

diff --git a/gdb/testsuite/gdb.base/step-over-clone.c b/gdb/testsuite/gdb.base/step-over-clone.c
new file mode 100644
index 0000000..43b1933
--- /dev/null
+++ b/gdb/testsuite/gdb.base/step-over-clone.c
@@ -0,0 +1,53 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2016 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/>.  */
+
+#define _GNU_SOURCE
+#include <stdlib.h>
+#include <unistd.h>
+#include <sched.h>
+
+static void
+marker () {}
+
+#define STACK_SIZE 0x1000
+
+static int
+clone_fn (void *unused)
+{
+  return 0;
+}
+
+int
+main (void)
+{
+  int i, pid;
+  unsigned char *stack[6];
+
+  for (i = 0; i < (sizeof (stack) / sizeof (stack[0])); i++)
+    stack[i] = malloc (STACK_SIZE);
+
+  for (i = 0; i < (sizeof (stack) / sizeof (stack[0])); i++)
+    {
+      pid = clone (clone_fn, stack[i] + STACK_SIZE, CLONE_FILES | CLONE_VM,
+		   NULL);
+    }
+
+  for (i = 0; i < (sizeof (stack) / sizeof (stack[0])); i++)
+    free (stack[i]);
+
+  marker ();
+}
diff --git a/gdb/testsuite/gdb.base/step-over-syscall.exp b/gdb/testsuite/gdb.base/step-over-syscall.exp
index 863194b..e5a3d55 100644
--- a/gdb/testsuite/gdb.base/step-over-syscall.exp
+++ b/gdb/testsuite/gdb.base/step-over-syscall.exp
@@ -122,6 +122,13 @@ proc step_over_syscall { syscall } {
 	foreach displaced $disp_step_opts {
 	    with_test_prefix "displaced $displaced" {
 
+		if { $displaced == "on" && $syscall == "clone" } {
+		    # GDB doesn't support step over clone syscall with
+		    # displaced stepping.
+		    kfail "gdb/19675" "single step over clone"
+		    continue
+		}
+
 		gdb_test "continue" \
 		    "Continuing\\..*Breakpoint \[0-9\]+, (.* in |__libc_|)$syscall \\(\\).*" \
 		    "continue to $syscall (3rd time)"
@@ -187,6 +194,15 @@ proc step_over_syscall { syscall } {
 			}
 		    }
 
+		if { $syscall == "clone" } {
+		    # Create a breakpoint in the child with the condition
+		    # which is false, so that GDBserver can get the
+		    # event from the child but GDB doesn't see it.  In
+		    # this way, we don't have to adjust test flow for
+		    # "clone".
+		    gdb_test "break clone_fn if main == 0"
+		}
+
 		gdb_test "continue" "Continuing\\..*Breakpoint \[0-9\]+, (.* in |__libc_|)$syscall \\(\\).*" \
 		    "continue to $syscall again"
 
@@ -206,3 +222,4 @@ proc step_over_syscall { syscall } {
 
 step_over_syscall "fork"
 step_over_syscall "vfork"
+step_over_syscall "clone"
-- 
1.9.1