def test_remote(self):
"""
Tests GDBRemote interaction with a GDBServer
"""
s = gdb.GDBServer()
r = gdb.GDBRemote('127.0.0.1', s.port)
r.connect()
r.cmd("qSupported")
r.cmd("qfThreadInfo")
s.exit()
def reverse_debugging(self, shift=7, args=None):
logger = logging.getLogger('replay')
# create qcow2 for snapshots
logger.info('creating qcow2 image for VM snapshots')
image_path = os.path.join(self.workdir, 'disk.qcow2')
qemu_img = os.path.join(BUILD_DIR, 'qemu-img')
if not os.path.exists(qemu_img):
qemu_img = find_command('qemu-img', False)
if qemu_img is False:
self.cancel('Could not find "qemu-img", which is required to '
'create the temporary qcow2 image')
cmd = '%s create -f qcow2 %s 128M' % (qemu_img, image_path)
process.run(cmd)
replay_path = os.path.join(self.workdir, 'replay.bin')
# record the log
vm = self.run_vm(True, shift, args, replay_path, image_path)
while self.vm_get_icount(vm) <= self.STEPS:
pass
last_icount = self.vm_get_icount(vm)
vm.shutdown()
logger.info("recorded log with %s+ steps" % last_icount)
# replay and run debug commands
vm = self.run_vm(False, shift, args, replay_path, image_path)
logger.info('connecting to gdbstub')
g = gdb.GDBRemote('127.0.0.1', 1234, False, False)
g.connect()
r = g.cmd(b'qSupported')
if b'qXfer:features:read+' in r:
g.cmd(b'qXfer:features:read:target.xml:0,ffb')
if b'ReverseStep+' not in r:
self.fail('Reverse step is not supported by QEMU')
if b'ReverseContinue+' not in r:
self.fail('Reverse continue is not supported by QEMU')
logger.info('stepping forward')
steps = []
# record first instruction addresses
for _ in range(self.STEPS):
pc = self.get_pc(g)
logger.info('saving position %x' % pc)
steps.append(pc)
self.gdb_step(g)
# visit the recorded instruction in reverse order
logger.info('stepping backward')
for addr in steps[::-1]:
self.gdb_bstep(g)
self.check_pc(g, addr)
logger.info('found position %x' % addr)
logger.info('seeking to the end (icount %s)' % (last_icount - 1))
vm.qmp('replay-break', icount=last_icount - 1)
# continue - will return after pausing
g.cmd(b'c', b'T02thread:01;')
logger.info('setting breakpoints')
for addr in steps:
# hardware breakpoint at addr with len=1
g.cmd(b'Z1,%x,1' % addr, b'OK')
logger.info('running reverse continue to reach %x' % steps[-1])
# reverse continue - will return after stopping at the breakpoint
g.cmd(b'bc', b'T05thread:01;')
# assume that none of the first instructions is executed again
# breaking the order of the breakpoints
self.check_pc(g, steps[-1])
logger.info('successfully reached %x' % steps[-1])
logger.info('exitting gdb and qemu')
vm.shutdown()