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Improve trace_inputs.py for Ubuntu 14.04 and fix regressions.
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It's mostly working around the sandbox and other things plus an earlier commit
49abac8 that had broken it.

This change is just enough to get going, nothing more.

[email protected]
BUG=

Review-Url: https://codereview.chromium.org/2208833002
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@maruel
maruel authored and Commit bot committed Aug 3, 2016
1 parent e448e8e commit f1a95e3
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Showing 2 changed files with 66 additions and 8 deletions.
5 changes: 3 additions & 2 deletions client/tests/trace_inputs_test.py
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Original file line number Diff line number Diff line change
Expand Up @@ -122,7 +122,7 @@ def test_CsvReader(self):
class StraceInputs(unittest.TestCase):
# Represents the root process pid (an arbitrary number).
_ROOT_PID = 27
_CHILD_PID = 14
_CHILD_PID = 24
_GRAND_CHILD_PID = 70

@staticmethod
Expand Down Expand Up @@ -464,6 +464,7 @@ def test_futex_missing_in_partial_action(self):
def test_futex_missing_in_partial_action_with_no_process(self):
# That's how futex() calls roll even more (again).
lines = [
(self._ROOT_PID, 'syscall_317(0, 0, 0, 0, 0, 0) = 0'),
(self._ROOT_PID, 'futex(0x7134840, FUTEX_WAIT_PRIVATE, 2, '
'NULL <ptrace(SYSCALL):No such process>'),
]
Expand All @@ -477,7 +478,7 @@ def test_futex_missing_in_partial_action_with_no_process(self):
'pid': self._ROOT_PID,
},
}
self.assertContext(lines, ROOT_DIR, expected, True)
self.assertContext(lines, ROOT_DIR, expected, False)

def test_getcwd(self):
lines = [
Expand Down
69 changes: 63 additions & 6 deletions client/trace_inputs.py
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Original file line number Diff line number Diff line change
Expand Up @@ -339,7 +339,7 @@ def full_path(self):
def real_path(self):
"""Returns the path with symlinks resolved."""
if not self._real_path:
self._real_path = fs.path.realpath(self.full_path)
self._real_path = os.path.realpath(self.full_path)
return self._real_path

@property
Expand Down Expand Up @@ -556,7 +556,7 @@ def strip_root(self, root):
accessed through any symlink which points to the same directory.
"""
# Resolve any symlink
root = fs.realpath(root)
root = os.path.realpath(root)
root = (
file_path.get_native_path_case(root).rstrip(os.path.sep) + os.path.sep)
logging.debug('strip_root(%s)' % root)
Expand Down Expand Up @@ -847,6 +847,9 @@ class Process(ApiBase.Context.Process):
RE_PROCESS_EXITED = re.compile(r'^\+\+\+ exited with (\d+) \+\+\+')
# A call was canceled. Ignore any prefix.
RE_UNAVAILABLE = re.compile(r'^.*\)\s*= \? <unavailable>$')
# The process has exited due to the ptrace sandbox. RE_PROCESS_EXITED will
# follow on next line.
RE_PTRACE = re.compile(r'^.*<ptrace\(SYSCALL\):No such process>$')
# Happens when strace fails to even get the function name.
UNNAMED_FUNCTION = '????'

Expand Down Expand Up @@ -991,6 +994,13 @@ def on_line(self, line):
# make sure any self._pending_calls[anything] is properly flushed.
return

match = self.RE_PTRACE.match(line)
if match:
# Not sure what this means. Anyhow, the process died.
# TODO(maruel): Add note that only RE_PROCESS_EXITED is valid
# afterward.
return

match = self.RE_RESUMED.match(line)
if match:
if match.group(1) not in self._pending_calls:
Expand Down Expand Up @@ -1060,6 +1070,12 @@ def handle_close(self, _args, _result):
def handle_chmod(self, args, _result):
self._handle_file(args[0], Results.File.WRITE)

@parse_args(r'^\"(.+?)\"$', False)
def handle_chroot(self, _args, _result):
# This is used by Chromium's sandbox. See
# https://chromium.googlesource.com/chromium/src/+/master/sandbox/linux/suid/sandbox.c
pass

@parse_args(r'^\"(.+?)\", (\d+)$', False)
def handle_creat(self, args, _result):
self._handle_file(args[0], Results.File.WRITE)
Expand Down Expand Up @@ -1095,6 +1111,11 @@ def handle_fallocate(self, _args, result):
def handle_fork(self, args, result):
self._handle_unknown('fork', args, result)

@parse_args(r'^(\d+), \"(.*?)\", ({.+}), (\d+)$', True)
def handle_fstatat64(self, _args, _result):
# TODO(maruel): Handle.
pass

def handle_futex(self, _args, _result):
pass

Expand Down Expand Up @@ -1128,6 +1149,11 @@ def handle_mkdir(self, _args, _result):
# We track content, not directories.
pass

@parse_args(r'^(\d+|AT_FDCWD), \".*?\", ({.+}), (\d+)$', True)
def handle_newfstatat(self, _args, _result):
# TODO(maruel): Handle
pass

@parse_args(r'^(\".*?\"|0x[a-f0-9]+), ([A-Z\_\|]+)(|, \d+)$', False)
def handle_open(self, args, _result):
if 'O_DIRECTORY' in args[1]:
Expand Down Expand Up @@ -1184,11 +1210,24 @@ def handle_stat(self, args, _result):
if not args[0].startswith('0x'):
self._handle_file(args[0][1:-1], Results.File.TOUCHED)

@parse_args(r'^(\".+?\"|0x[a-f0-9]+), \{.+?\}$', True)
def handle_stat64(self, args, _result):
if not args[0].startswith('0x'):
self._handle_file(args[0][1:-1], Results.File.TOUCHED)

@parse_args(r'^\"(.+?)\", \"(.+?)\"$', True)
def handle_symlink(self, args, _result):
self._handle_file(args[0], Results.File.TOUCHED)
self._handle_file(args[1], Results.File.WRITE)

@parse_args(
r'^([0-9xa-f]+), ([0-9xa-f]+), ([0-9xa-f]+), ([0-9xa-f]+), '
r'([0-9xa-f]+), ([0-9xa-f]+)$',
False)
def handle_syscall_317(self, _args, _result):
# move_pages()
pass

@parse_args(r'^\"(.+?)\", \d+', True)
def handle_truncate(self, args, _result):
self._handle_file(args[0], Results.File.WRITE)
Expand Down Expand Up @@ -1224,13 +1263,18 @@ def _handling_forking(self, name, result):
return
# Update the other process right away.
childpid = int(result)
if childpid < 20:
# Ignore, it's probably the Chromium sandbox.
return
child = self._root().get_or_set_proc(childpid)
if child.parentid is not None or childpid in self.children:
raise TracingFailure(
'Found internal inconsitency in process lifetime detection '
'during a %s() call' % name,
'during a %s()=%s call:\n%s' % (
name,
result,
sorted(self._root()._process_lookup)),
None, None, None)

# Copy the cwd object.
child.initial_cwd = self.get_cwd()
child.parentid = self.pid
Expand Down Expand Up @@ -1289,6 +1333,15 @@ def to_results(self):
self.root_process = root[0]
# Save it for later.
self.root_pid = self.root_process.pid
else:
raise TracingFailure(
'Found internal inconsitency in process lifetime detection '
'while finding the root process',
None,
None,
None,
self.root_pid,
sorted(self._process_lookup))
else:
# The sudo case. The traced process was started manually so its pid is
# known.
Expand Down Expand Up @@ -1371,7 +1424,10 @@ def trace(self, cmd, cwd, tracename, output):
stderr = subprocess.STDOUT

# Ensure all file related APIs are hooked.
traces = ','.join(Strace.Context.traces() + ['file'])
traces = ','.join(
[i for i in Strace.Context.traces()
if not i.startswith('syscall_')] +
['file'])
flags = [
# Each child process has its own trace file. It is necessary because
# strace may generate corrupted log file if multiple processes are
Expand All @@ -1390,6 +1446,7 @@ def trace(self, cmd, cwd, tracename, output):
'-e', 'trace=%s' % traces,
'-o', self._logname + '.' + tracename,
]
logging.info('%s', flags)

if self.use_sudo:
pipe_r, pipe_w = os.pipe()
Expand Down Expand Up @@ -3173,7 +3230,7 @@ def extract_directories(root_dir, files, blacklist):
# It is important for root_dir to not be a symlinked path, make sure to call
# os.path.realpath() as needed.
assert not root_dir or (
fs.realpath(file_path.get_native_path_case(root_dir)) == root_dir)
os.path.realpath(file_path.get_native_path_case(root_dir)) == root_dir)
assert not any(isinstance(f, Results.Directory) for f in files)
# Remove non existent files.
files = [f for f in files if f.existent]
Expand Down

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