tests/tcg: Add two follow-fork-mode tests

Add follow-fork-mode child and and follow-fork-mode parent tests.
Check for the obvious pitfalls, such as lingering breakpoints,
catchpoints, and single-step mode.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <20240219141628.246823-13-iii@linux.ibm.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240305121005.3528075-14-alex.bennee@linaro.org>

tests/tcg/multiarch/gdbstub/follow-fork-mode-child.py

@@ -0,0 +1,40 @@
+"""Test GDB's follow-fork-mode child.
+
+SPDX-License-Identifier: GPL-2.0-or-later
+"""
+from test_gdbstub import main, report
+
+
+def run_test():
+    """Run through the tests one by one"""
+    gdb.execute("set follow-fork-mode child")
+    # Check that the parent breakpoints are unset.
+    gdb.execute("break break_after_fork")
+    # Check that the parent syscall catchpoints are unset.
+    # Skip this check on the architectures that don't have them.
+    have_fork_syscall = False
+    for fork_syscall in ("fork", "clone", "clone2", "clone3"):
+        try:
+            gdb.execute("catch syscall {}".format(fork_syscall))
+        except gdb.error:
+            pass
+        else:
+            have_fork_syscall = True
+    gdb.execute("continue")
+    for i in range(42):
+        if have_fork_syscall:
+            # syscall entry.
+            if i % 2 == 0:
+                # Check that the parent single-stepping is turned off.
+                gdb.execute("si")
+            else:
+                gdb.execute("continue")
+            # syscall exit.
+            gdb.execute("continue")
+        # break_after_fork()
+        gdb.execute("continue")
+    exitcode = int(gdb.parse_and_eval("$_exitcode"))
+    report(exitcode == 42, "{} == 42".format(exitcode))
+
+
+main(run_test)

tests/tcg/multiarch/gdbstub/follow-fork-mode-parent.py

@@ -0,0 +1,16 @@
+"""Test GDB's follow-fork-mode parent.
+
+SPDX-License-Identifier: GPL-2.0-or-later
+"""
+from test_gdbstub import main, report
+
+
+def run_test():
+    """Run through the tests one by one"""
+    gdb.execute("set follow-fork-mode parent")
+    gdb.execute("continue")
+    exitcode = int(gdb.parse_and_eval("$_exitcode"))
+    report(exitcode == 0, "{} == 0".format(exitcode))
+
+
+main(run_test)