# Verify that gdb can pretty-print the various PyObject* types # # The code for testing gdb was adapted from similar work in Unladen Swallow's # Lib/test/test_jit_gdb.py import os import re import subprocess import sys import unittest from test.support import run_unittest, findfile try: gdb_version, _ = subprocess.Popen(["gdb", "--version"], stdout=subprocess.PIPE).communicate() except OSError: # This is what "no gdb" looks like. There may, however, be other # errors that manifest this way too. raise unittest.SkipTest("Couldn't find gdb on the path") gdb_version_number = re.search(b"^GNU gdb [^\d]*(\d+)\.", gdb_version) if int(gdb_version_number.group(1)) < 7: raise unittest.SkipTest("gdb versions before 7.0 didn't support python embedding" " Saw:\n" + gdb_version.decode('ascii', 'replace')) # Verify that "gdb" was built with the embedded python support enabled: cmd = "--eval-command=python import sys; print sys.version_info" p = subprocess.Popen(["gdb", "--batch", cmd], stdout=subprocess.PIPE) gdbpy_version, _ = p.communicate() if gdbpy_version == b'': raise unittest.SkipTest("gdb not built with embedded python support") def gdb_has_frame_select(): # Does this build of gdb have gdb.Frame.select ? cmd = "--eval-command=python print(dir(gdb.Frame))" p = subprocess.Popen(["gdb", "--batch", cmd], stdout=subprocess.PIPE) stdout, _ = p.communicate() m = re.match(br'.*\[(.*)\].*', stdout) if not m: raise unittest.SkipTest("Unable to parse output from gdb.Frame.select test") gdb_frame_dir = m.group(1).split(b', ') return b"'select'" in gdb_frame_dir HAS_PYUP_PYDOWN = gdb_has_frame_select() BREAKPOINT_FN='builtin_id' class DebuggerTests(unittest.TestCase): """Test that the debugger can debug Python.""" def run_gdb(self, *args): """Runs gdb with the command line given by *args. Returns its stdout, stderr """ out, err = subprocess.Popen( args, stdout=subprocess.PIPE, stderr=subprocess.PIPE, ).communicate() return out.decode('utf-8', 'replace'), err.decode('utf-8', 'replace') def get_stack_trace(self, source=None, script=None, breakpoint=BREAKPOINT_FN, cmds_after_breakpoint=None, import_site=False): ''' Run 'python -c SOURCE' under gdb with a breakpoint. Support injecting commands after the breakpoint is reached Returns the stdout from gdb cmds_after_breakpoint: if provided, a list of strings: gdb commands ''' # We use "set breakpoint pending yes" to avoid blocking with a: # Function "foo" not defined. # Make breakpoint pending on future shared library load? (y or [n]) # error, which typically happens python is dynamically linked (the # breakpoints of interest are to be found in the shared library) # When this happens, we still get: # Function "textiowrapper_write" not defined. # emitted to stderr each time, alas. # Initially I had "--eval-command=continue" here, but removed it to # avoid repeated print breakpoints when traversing hierarchical data # structures # Generate a list of commands in gdb's language: commands = ['set breakpoint pending yes', 'break %s' % breakpoint, 'run'] if cmds_after_breakpoint: commands += cmds_after_breakpoint else: commands += ['backtrace'] # print commands # Use "commands" to generate the arguments with which to invoke "gdb": args = ["gdb", "--batch"] args += ['--eval-command=%s' % cmd for cmd in commands] args += ["--args", sys.executable] if not import_site: # -S suppresses the default 'import site' args += ["-S"] if source: args += ["-c", source] elif script: args += [script] # print args # print ' '.join(args) # Use "args" to invoke gdb, capturing stdout, stderr: out, err = self.run_gdb(*args) # Ignore some noise on stderr due to the pending breakpoint: err = err.replace('Function "%s" not defined.\n' % breakpoint, '') # Ignore some other noise on stderr (http://bugs.python.org/issue8600) err = err.replace("warning: Unable to find libthread_db matching" " inferior's thread library, thread debugging will" " not be available.\n", '') # Ensure no unexpected error messages: self.assertEquals(err, '') return out def get_gdb_repr(self, source, cmds_after_breakpoint=None, import_site=False): # Given an input python source representation of data, # run "python -c'id(DATA)'" under gdb with a breakpoint on # builtin_id and scrape out gdb's representation of the "op" # parameter, and verify that the gdb displays the same string # # Verify that the gdb displays the expected string # # For a nested structure, the first time we hit the breakpoint will # give us the top-level structure gdb_output = self.get_stack_trace(source, breakpoint=BREAKPOINT_FN, cmds_after_breakpoint=cmds_after_breakpoint, import_site=import_site) # gdb can insert additional '\n' and space characters in various places # in its output, depending on the width of the terminal it's connected # to (using its "wrap_here" function) m = re.match('.*#0\s+builtin_id\s+\(self\=.*,\s+v=\s*(.*?)\)\s+at\s+Python/bltinmodule.c.*', gdb_output, re.DOTALL) if not m: self.fail('Unexpected gdb output: %r\n%s' % (gdb_output, gdb_output)) return m.group(1), gdb_output def assertEndsWith(self, actual, exp_end): '''Ensure that the given "actual" string ends with "exp_end"''' self.assert_(actual.endswith(exp_end), msg='%r did not end with %r' % (actual, exp_end)) def assertMultilineMatches(self, actual, pattern): m = re.match(pattern, actual, re.DOTALL) if not m: self.fail(msg='%r did not match %r' % (actual, pattern)) def get_sample_script(self): return findfile('gdb_sample.py') class PrettyPrintTests(DebuggerTests): def test_getting_backtrace(self): gdb_output = self.get_stack_trace('id(42)') self.assertTrue(BREAKPOINT_FN in gdb_output) def assertGdbRepr(self, val, exp_repr=None, cmds_after_breakpoint=None): # Ensure that gdb's rendering of the value in a debugged process # matches repr(value) in this process: gdb_repr, gdb_output = self.get_gdb_repr('id(' + repr(val) + ')', cmds_after_breakpoint) if not exp_repr: exp_repr = repr(val) self.assertEquals(gdb_repr, exp_repr, ('%r did not equal expected %r; full output was:\n%s' % (gdb_repr, exp_repr, gdb_output))) def test_int(self): 'Verify the pretty-printing of various "int"/long values' self.assertGdbRepr(42) self.assertGdbRepr(0) self.assertGdbRepr(-7) self.assertGdbRepr(1000000000000) self.assertGdbRepr(-1000000000000000) def test_singletons(self): 'Verify the pretty-printing of True, False and None' self.assertGdbRepr(True) self.assertGdbRepr(False) self.assertGdbRepr(None) def test_dicts(self): 'Verify the pretty-printing of dictionaries' self.assertGdbRepr({}) self.assertGdbRepr({'foo': 'bar'}) self.assertGdbRepr({'foo': 'bar', 'douglas':42}) def test_lists(self): 'Verify the pretty-printing of lists' self.assertGdbRepr([]) self.assertGdbRepr(list(range(5))) def test_bytes(self): 'Verify the pretty-printing of bytes' self.assertGdbRepr(b'') self.assertGdbRepr(b'And now for something hopefully the same') self.assertGdbRepr(b'string with embedded NUL here \0 and then some more text') self.assertGdbRepr(b'this is a tab:\t' b' this is a slash-N:\n' b' this is a slash-R:\r' ) self.assertGdbRepr(b'this is byte 255:\xff and byte 128:\x80') self.assertGdbRepr(bytes([b for b in range(255)])) def test_strings(self): 'Verify the pretty-printing of unicode strings' self.assertGdbRepr('') self.assertGdbRepr('And now for something hopefully the same') self.assertGdbRepr('string with embedded NUL here \0 and then some more text') # Test printing a single character: # U+2620 SKULL AND CROSSBONES self.assertGdbRepr('\u2620') # Test printing a Japanese unicode string # (I believe this reads "mojibake", using 3 characters from the CJK # Unified Ideographs area, followed by U+3051 HIRAGANA LETTER KE) self.assertGdbRepr('\u6587\u5b57\u5316\u3051') # Test a character outside the BMP: # U+1D121 MUSICAL SYMBOL C CLEF # This is: # UTF-8: 0xF0 0x9D 0x84 0xA1 # UTF-16: 0xD834 0xDD21 if sys.maxunicode == 0x10FFFF: # wide unicode: self.assertGdbRepr(chr(0x1D121)) else: # narrow unicode: self.assertGdbRepr(chr(0x1D121), "'\\U0000d834\\U0000dd21'") def test_tuples(self): 'Verify the pretty-printing of tuples' self.assertGdbRepr(tuple()) self.assertGdbRepr((1,), '(1,)') self.assertGdbRepr(('foo', 'bar', 'baz')) def test_sets(self): 'Verify the pretty-printing of sets' self.assertGdbRepr(set()) self.assertGdbRepr(set(['a', 'b'])) self.assertGdbRepr(set([4, 5, 6])) # Ensure that we handle sets containing the "dummy" key value, # which happens on deletion: gdb_repr, gdb_output = self.get_gdb_repr('''s = set(['a','b']) s.pop() id(s)''') self.assertEquals(gdb_repr, "{'b'}") def test_frozensets(self): 'Verify the pretty-printing of frozensets' self.assertGdbRepr(frozenset()) self.assertGdbRepr(frozenset(['a', 'b'])) self.assertGdbRepr(frozenset([4, 5, 6])) def test_exceptions(self): # Test a RuntimeError gdb_repr, gdb_output = self.get_gdb_repr(''' try: raise RuntimeError("I am an error") except RuntimeError as e: id(e) ''') self.assertEquals(gdb_repr, "RuntimeError('I am an error',)") # Test division by zero: gdb_repr, gdb_output = self.get_gdb_repr(''' try: a = 1 / 0 except ZeroDivisionError as e: id(e) ''') self.assertEquals(gdb_repr, "ZeroDivisionError('division by zero',)") def test_modern_class(self): 'Verify the pretty-printing of new-style class instances' gdb_repr, gdb_output = self.get_gdb_repr(''' class Foo: pass foo = Foo() foo.an_int = 42 id(foo)''') m = re.match(r'', gdb_repr) self.assertTrue(m, msg='Unexpected new-style class rendering %r' % gdb_repr) def test_subclassing_list(self): 'Verify the pretty-printing of an instance of a list subclass' gdb_repr, gdb_output = self.get_gdb_repr(''' class Foo(list): pass foo = Foo() foo += [1, 2, 3] foo.an_int = 42 id(foo)''') m = re.match(r'', gdb_repr) self.assertTrue(m, msg='Unexpected new-style class rendering %r' % gdb_repr) def test_subclassing_tuple(self): 'Verify the pretty-printing of an instance of a tuple subclass' # This should exercise the negative tp_dictoffset code in the # new-style class support gdb_repr, gdb_output = self.get_gdb_repr(''' class Foo(tuple): pass foo = Foo((1, 2, 3)) foo.an_int = 42 id(foo)''') m = re.match(r'', gdb_repr) self.assertTrue(m, msg='Unexpected new-style class rendering %r' % gdb_repr) def assertSane(self, source, corruption, exprepr=None): '''Run Python under gdb, corrupting variables in the inferior process immediately before taking a backtrace. Verify that the variable's representation is the expected failsafe representation''' if corruption: cmds_after_breakpoint=[corruption, 'backtrace'] else: cmds_after_breakpoint=['backtrace'] gdb_repr, gdb_output = \ self.get_gdb_repr(source, cmds_after_breakpoint=cmds_after_breakpoint) if exprepr: if gdb_repr == exprepr: # gdb managed to print the value in spite of the corruption; # this is good (see http://bugs.python.org/issue8330) return # Match anything for the type name; 0xDEADBEEF could point to # something arbitrary (see http://bugs.python.org/issue8330) pattern = '<.* at remote 0x[0-9a-f]+>' m = re.match(pattern, gdb_repr) if not m: self.fail('Unexpected gdb representation: %r\n%s' % \ (gdb_repr, gdb_output)) def test_NULL_ptr(self): 'Ensure that a NULL PyObject* is handled gracefully' gdb_repr, gdb_output = ( self.get_gdb_repr('id(42)', cmds_after_breakpoint=['set variable v=0', 'backtrace']) ) self.assertEquals(gdb_repr, '0x0') def test_NULL_ob_type(self): 'Ensure that a PyObject* with NULL ob_type is handled gracefully' self.assertSane('id(42)', 'set v->ob_type=0') def test_corrupt_ob_type(self): 'Ensure that a PyObject* with a corrupt ob_type is handled gracefully' self.assertSane('id(42)', 'set v->ob_type=0xDEADBEEF', exprepr='42') def test_corrupt_tp_flags(self): 'Ensure that a PyObject* with a type with corrupt tp_flags is handled' self.assertSane('id(42)', 'set v->ob_type->tp_flags=0x0', exprepr='42') def test_corrupt_tp_name(self): 'Ensure that a PyObject* with a type with corrupt tp_name is handled' self.assertSane('id(42)', 'set v->ob_type->tp_name=0xDEADBEEF', exprepr='42') def test_builtins_help(self): 'Ensure that the new-style class _Helper in site.py can be handled' # (this was the issue causing tracebacks in # http://bugs.python.org/issue8032#msg100537 ) gdb_repr, gdb_output = self.get_gdb_repr('id(__builtins__.help)', import_site=True) m = re.match(r'<_Helper at remote 0x[0-9a-f]+>', gdb_repr) self.assertTrue(m, msg='Unexpected rendering %r' % gdb_repr) def test_selfreferential_list(self): '''Ensure that a reference loop involving a list doesn't lead proxyval into an infinite loop:''' gdb_repr, gdb_output = \ self.get_gdb_repr("a = [3, 4, 5] ; a.append(a) ; id(a)") self.assertEquals(gdb_repr, '[3, 4, 5, [...]]') gdb_repr, gdb_output = \ self.get_gdb_repr("a = [3, 4, 5] ; b = [a] ; a.append(b) ; id(a)") self.assertEquals(gdb_repr, '[3, 4, 5, [[...]]]') def test_selfreferential_dict(self): '''Ensure that a reference loop involving a dict doesn't lead proxyval into an infinite loop:''' gdb_repr, gdb_output = \ self.get_gdb_repr("a = {} ; b = {'bar':a} ; a['foo'] = b ; id(a)") self.assertEquals(gdb_repr, "{'foo': {'bar': {...}}}") def test_selfreferential_old_style_instance(self): gdb_repr, gdb_output = \ self.get_gdb_repr(''' class Foo: pass foo = Foo() foo.an_attr = foo id(foo)''') self.assertTrue(re.match('\) at remote 0x[0-9a-f]+>', gdb_repr), 'Unexpected gdb representation: %r\n%s' % \ (gdb_repr, gdb_output)) def test_selfreferential_new_style_instance(self): gdb_repr, gdb_output = \ self.get_gdb_repr(''' class Foo(object): pass foo = Foo() foo.an_attr = foo id(foo)''') self.assertTrue(re.match('\) at remote 0x[0-9a-f]+>', gdb_repr), 'Unexpected gdb representation: %r\n%s' % \ (gdb_repr, gdb_output)) gdb_repr, gdb_output = \ self.get_gdb_repr(''' class Foo(object): pass a = Foo() b = Foo() a.an_attr = b b.an_attr = a id(a)''') self.assertTrue(re.match('\) at remote 0x[0-9a-f]+>\) at remote 0x[0-9a-f]+>', gdb_repr), 'Unexpected gdb representation: %r\n%s' % \ (gdb_repr, gdb_output)) def test_truncation(self): 'Verify that very long output is truncated' gdb_repr, gdb_output = self.get_gdb_repr('id(list(range(1000)))') self.assertEquals(gdb_repr, "[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, " "14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, " "27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, " "40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, " "53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, " "66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, " "79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, " "92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, " "104, 105, 106, 107, 108, 109, 110, 111, 112, 113, " "114, 115, 116, 117, 118, 119, 120, 121, 122, 123, " "124, 125, 126, 127, 128, 129, 130, 131, 132, 133, " "134, 135, 136, 137, 138, 139, 140, 141, 142, 143, " "144, 145, 146, 147, 148, 149, 150, 151, 152, 153, " "154, 155, 156, 157, 158, 159, 160, 161, 162, 163, " "164, 165, 166, 167, 168, 169, 170, 171, 172, 173, " "174, 175, 176, 177, 178, 179, 180, 181, 182, 183, " "184, 185, 186, 187, 188, 189, 190, 191, 192, 193, " "194, 195, 196, 197, 198, 199, 200, 201, 202, 203, " "204, 205, 206, 207, 208, 209, 210, 211, 212, 213, " "214, 215, 216, 217, 218, 219, 220, 221, 222, 223, " "224, 225, 226...(truncated)") self.assertEquals(len(gdb_repr), 1024 + len('...(truncated)')) def test_builtin_method(self): gdb_repr, gdb_output = self.get_gdb_repr('import sys; id(sys.stdout.readlines)') self.assertTrue(re.match('', gdb_repr), 'Unexpected gdb representation: %r\n%s' % \ (gdb_repr, gdb_output)) def test_frames(self): gdb_output = self.get_stack_trace(''' def foo(a, b, c): pass foo(3, 4, 5) id(foo.__code__)''', breakpoint='builtin_id', cmds_after_breakpoint=['print (PyFrameObject*)(((PyCodeObject*)v)->co_zombieframe)'] ) self.assertTrue(re.match('.*\s+\$1 =\s+Frame 0x[0-9a-f]+, for file , line 3, in foo \(\)\s+.*', gdb_output, re.DOTALL), 'Unexpected gdb representation: %r\n%s' % (gdb_output, gdb_output)) class PyListTests(DebuggerTests): def assertListing(self, expected, actual): self.assertEndsWith(actual, expected) def test_basic_command(self): 'Verify that the "py-list" command works' bt = self.get_stack_trace(script=self.get_sample_script(), cmds_after_breakpoint=['py-list']) self.assertListing(' 5 \n' ' 6 def bar(a, b, c):\n' ' 7 baz(a, b, c)\n' ' 8 \n' ' 9 def baz(*args):\n' ' >10 id(42)\n' ' 11 \n' ' 12 foo(1, 2, 3)\n', bt) def test_one_abs_arg(self): 'Verify the "py-list" command with one absolute argument' bt = self.get_stack_trace(script=self.get_sample_script(), cmds_after_breakpoint=['py-list 9']) self.assertListing(' 9 def baz(*args):\n' ' >10 id(42)\n' ' 11 \n' ' 12 foo(1, 2, 3)\n', bt) def test_two_abs_args(self): 'Verify the "py-list" command with two absolute arguments' bt = self.get_stack_trace(script=self.get_sample_script(), cmds_after_breakpoint=['py-list 1,3']) self.assertListing(' 1 # Sample script for use by test_gdb.py\n' ' 2 \n' ' 3 def foo(a, b, c):\n', bt) class StackNavigationTests(DebuggerTests): @unittest.skipUnless(HAS_PYUP_PYDOWN, "test requires py-up/py-down commands") def test_pyup_command(self): 'Verify that the "py-up" command works' bt = self.get_stack_trace(script=self.get_sample_script(), cmds_after_breakpoint=['py-up']) self.assertMultilineMatches(bt, r'''^.* #[0-9]+ Frame 0x[0-9a-f]+, for file .*gdb_sample.py, line 7, in bar \(a=1, b=2, c=3\) baz\(a, b, c\) $''') @unittest.skipUnless(HAS_PYUP_PYDOWN, "test requires py-up/py-down commands") def test_down_at_bottom(self): 'Verify handling of "py-down" at the bottom of the stack' bt = self.get_stack_trace(script=self.get_sample_script(), cmds_after_breakpoint=['py-down']) self.assertEndsWith(bt, 'Unable to find a newer python frame\n') @unittest.skipUnless(HAS_PYUP_PYDOWN, "test requires py-up/py-down commands") def test_up_at_top(self): 'Verify handling of "py-up" at the top of the stack' bt = self.get_stack_trace(script=self.get_sample_script(), cmds_after_breakpoint=['py-up'] * 4) self.assertEndsWith(bt, 'Unable to find an older python frame\n') @unittest.skipUnless(HAS_PYUP_PYDOWN, "test requires py-up/py-down commands") def test_up_then_down(self): 'Verify "py-up" followed by "py-down"' bt = self.get_stack_trace(script=self.get_sample_script(), cmds_after_breakpoint=['py-up', 'py-down']) self.assertMultilineMatches(bt, r'''^.* #[0-9]+ Frame 0x[0-9a-f]+, for file .*gdb_sample.py, line 7, in bar \(a=1, b=2, c=3\) baz\(a, b, c\) #[0-9]+ Frame 0x[0-9a-f]+, for file .*gdb_sample.py, line 10, in baz \(args=\(1, 2, 3\)\) id\(42\) $''') class PyBtTests(DebuggerTests): def test_basic_command(self): 'Verify that the "py-bt" command works' bt = self.get_stack_trace(script=self.get_sample_script(), cmds_after_breakpoint=['py-bt']) self.assertMultilineMatches(bt, r'''^.* #[0-9]+ Frame 0x[0-9a-f]+, for file .*gdb_sample.py, line 7, in bar \(a=1, b=2, c=3\) baz\(a, b, c\) #[0-9]+ Frame 0x[0-9a-f]+, for file .*gdb_sample.py, line 4, in foo \(a=1, b=2, c=3\) bar\(a, b, c\) #[0-9]+ Frame 0x[0-9a-f]+, for file .*gdb_sample.py, line 12, in \(\) foo\(1, 2, 3\) ''') class PyPrintTests(DebuggerTests): def test_basic_command(self): 'Verify that the "py-print" command works' bt = self.get_stack_trace(script=self.get_sample_script(), cmds_after_breakpoint=['py-print args']) self.assertMultilineMatches(bt, r".*\nlocal 'args' = \(1, 2, 3\)\n.*") @unittest.skipUnless(HAS_PYUP_PYDOWN, "test requires py-up/py-down commands") def test_print_after_up(self): bt = self.get_stack_trace(script=self.get_sample_script(), cmds_after_breakpoint=['py-up', 'py-print c', 'py-print b', 'py-print a']) self.assertMultilineMatches(bt, r".*\nlocal 'c' = 3\nlocal 'b' = 2\nlocal 'a' = 1\n.*") def test_printing_global(self): bt = self.get_stack_trace(script=self.get_sample_script(), cmds_after_breakpoint=['py-print __name__']) self.assertMultilineMatches(bt, r".*\nglobal '__name__' = '__main__'\n.*") def test_printing_builtin(self): bt = self.get_stack_trace(script=self.get_sample_script(), cmds_after_breakpoint=['py-print len']) self.assertMultilineMatches(bt, r".*\nbuiltin 'len' = \n.*") class PyLocalsTests(DebuggerTests): def test_basic_command(self): bt = self.get_stack_trace(script=self.get_sample_script(), cmds_after_breakpoint=['py-locals']) self.assertMultilineMatches(bt, r".*\nargs = \(1, 2, 3\)\n.*") @unittest.skipUnless(HAS_PYUP_PYDOWN, "test requires py-up/py-down commands") def test_locals_after_up(self): bt = self.get_stack_trace(script=self.get_sample_script(), cmds_after_breakpoint=['py-up', 'py-locals']) self.assertMultilineMatches(bt, r".*\na = 1\nb = 2\nc = 3\n.*") def test_main(): run_unittest(PrettyPrintTests, PyListTests, StackNavigationTests, PyBtTests, PyPrintTests, PyLocalsTests ) if __name__ == "__main__": test_main()