mirror of https://github.com/python/cpython
Revert "GH-120754: Add a strace helper and test set of syscalls for o… (#123303)
Revert "GH-120754: Add a strace helper and test set of syscalls for open().read() (#121143)"
This reverts commit e38d0afe35.
This commit is contained in:
Shantanu
GitHub
parent
e38d0afe35
commit
52caaef6d0
|
|
@ -1,166 +0,0 @@
|
|||
import re
|
||||
import sys
|
||||
import textwrap
|
||||
import unittest
|
||||
from dataclasses import dataclass
|
||||
from functools import cache
|
||||
from test import support
|
||||
from test.support.script_helper import run_python_until_end
|
||||
|
||||
_strace_binary = "/usr/bin/strace"
|
||||
_syscall_regex = re.compile(
|
||||
r"(?P<syscall>[^(]*)\((?P<args>[^)]*)\)\s*[=]\s*(?P<returncode>.+)")
|
||||
_returncode_regex = re.compile(
|
||||
br"\+\+\+ exited with (?P<returncode>\d+) \+\+\+")
|
||||
|
||||
|
||||
@dataclass
|
||||
class StraceEvent:
|
||||
syscall: str
|
||||
args: list[str]
|
||||
returncode: str
|
||||
|
||||
|
||||
@dataclass
|
||||
class StraceResult:
|
||||
strace_returncode: int
|
||||
python_returncode: int
|
||||
|
||||
"""The event messages generated by strace. This is very similar to the
|
||||
stderr strace produces with returncode marker section removed."""
|
||||
event_bytes: bytes
|
||||
stdout: bytes
|
||||
stderr: bytes
|
||||
|
||||
def events(self):
|
||||
"""Parse event_bytes data into system calls for easier processing.
|
||||
|
||||
This assumes the program under inspection doesn't print any non-utf8
|
||||
strings which would mix into the strace output."""
|
||||
decoded_events = self.event_bytes.decode('utf-8')
|
||||
matches = [
|
||||
_syscall_regex.match(event)
|
||||
for event in decoded_events.splitlines()
|
||||
]
|
||||
return [
|
||||
StraceEvent(match["syscall"],
|
||||
[arg.strip() for arg in (match["args"].split(","))],
|
||||
match["returncode"]) for match in matches if match
|
||||
]
|
||||
|
||||
def sections(self):
|
||||
"""Find all "MARK <X>" writes and use them to make groups of events.
|
||||
|
||||
This is useful to avoid variable / overhead events, like those at
|
||||
interpreter startup or when opening a file so a test can verify just
|
||||
the small case under study."""
|
||||
current_section = "__startup"
|
||||
sections = {current_section: []}
|
||||
for event in self.events():
|
||||
if event.syscall == 'write' and len(
|
||||
event.args) > 2 and event.args[1].startswith("\"MARK "):
|
||||
# Found a new section, don't include the write in the section
|
||||
# but all events until next mark should be in that section
|
||||
current_section = event.args[1].split(
|
||||
" ", 1)[1].removesuffix('\\n"')
|
||||
if current_section not in sections:
|
||||
sections[current_section] = list()
|
||||
else:
|
||||
sections[current_section].append(event)
|
||||
|
||||
return sections
|
||||
|
||||
|
||||
@support.requires_subprocess()
|
||||
def strace_python(code, strace_flags, check=True):
|
||||
"""Run strace and return the trace.
|
||||
|
||||
Sets strace_returncode and python_returncode to `-1` on error."""
|
||||
res = None
|
||||
|
||||
def _make_error(reason, details):
|
||||
return StraceResult(
|
||||
strace_returncode=-1,
|
||||
python_returncode=-1,
|
||||
event_bytes=f"error({reason},details={details}) = -1".encode('utf-8'),
|
||||
stdout=res.out if res else "",
|
||||
stderr=res.err if res else "")
|
||||
|
||||
# Run strace, and get out the raw text
|
||||
try:
|
||||
res, cmd_line = run_python_until_end(
|
||||
"-c",
|
||||
textwrap.dedent(code),
|
||||
__run_using_command=[_strace_binary] + strace_flags)
|
||||
except OSError as err:
|
||||
return _make_error("Caught OSError", err)
|
||||
|
||||
if check and res.rc:
|
||||
res.fail(cmd_line)
|
||||
|
||||
# Get out program returncode
|
||||
stripped = res.err.strip()
|
||||
output = stripped.rsplit(b"\n", 1)
|
||||
if len(output) != 2:
|
||||
return _make_error("Expected strace events and exit code line",
|
||||
stripped[-50:])
|
||||
|
||||
returncode_match = _returncode_regex.match(output[1])
|
||||
if not returncode_match:
|
||||
return _make_error("Expected to find returncode in last line.",
|
||||
output[1][:50])
|
||||
|
||||
python_returncode = int(returncode_match["returncode"])
|
||||
if check and python_returncode:
|
||||
res.fail(cmd_line)
|
||||
|
||||
return StraceResult(strace_returncode=res.rc,
|
||||
python_returncode=python_returncode,
|
||||
event_bytes=output[0],
|
||||
stdout=res.out,
|
||||
stderr=res.err)
|
||||
|
||||
|
||||
def _get_events(code, strace_flags, prelude, cleanup):
|
||||
# NOTE: The flush is currently required to prevent the prints from getting
|
||||
# buffered and done all at once at exit
|
||||
prelude = textwrap.dedent(prelude)
|
||||
code = textwrap.dedent(code)
|
||||
cleanup = textwrap.dedent(cleanup)
|
||||
to_run = f"""
|
||||
print("MARK prelude", flush=True)
|
||||
{prelude}
|
||||
print("MARK code", flush=True)
|
||||
{code}
|
||||
print("MARK cleanup", flush=True)
|
||||
{cleanup}
|
||||
print("MARK __shutdown", flush=True)
|
||||
"""
|
||||
trace = strace_python(to_run, strace_flags)
|
||||
all_sections = trace.sections()
|
||||
return all_sections['code']
|
||||
|
||||
|
||||
def get_syscalls(code, strace_flags, prelude="", cleanup=""):
|
||||
"""Get the syscalls which a given chunk of python code generates"""
|
||||
events = _get_events(code, strace_flags, prelude=prelude, cleanup=cleanup)
|
||||
return [ev.syscall for ev in events]
|
||||
|
||||
|
||||
# Moderately expensive (spawns a subprocess), so share results when possible.
|
||||
@cache
|
||||
def _can_strace():
|
||||
res = strace_python("import sys; sys.exit(0)", [], check=False)
|
||||
assert res.events(), "Should have parsed multiple calls"
|
||||
|
||||
return res.strace_returncode == 0 and res.python_returncode == 0
|
||||
|
||||
|
||||
def requires_strace():
|
||||
if sys.platform != "linux":
|
||||
return unittest.skip("Linux only, requires strace.")
|
||||
|
||||
return unittest.skipUnless(_can_strace(), "Requires working strace")
|
||||
|
||||
|
||||
__all__ = ["requires_strace", "strace_python", "StraceEvent", "StraceResult"]
|
||||
|
|
@ -11,7 +11,7 @@ from functools import wraps
|
|||
|
||||
from test.support import (
|
||||
cpython_only, swap_attr, gc_collect, is_emscripten, is_wasi,
|
||||
infinite_recursion, strace_helper
|
||||
infinite_recursion,
|
||||
)
|
||||
from test.support.os_helper import (
|
||||
TESTFN, TESTFN_ASCII, TESTFN_UNICODE, make_bad_fd,
|
||||
|
|
@ -24,9 +24,6 @@ import _io # C implementation of io
|
|||
import _pyio # Python implementation of io
|
||||
|
||||
|
||||
_strace_flags=["--trace=%file,%desc"]
|
||||
|
||||
|
||||
class AutoFileTests:
|
||||
# file tests for which a test file is automatically set up
|
||||
|
||||
|
|
@ -362,94 +359,6 @@ class AutoFileTests:
|
|||
a = array('b', b'x'*10)
|
||||
f.readinto(a)
|
||||
|
||||
@strace_helper.requires_strace()
|
||||
def test_syscalls_read(self):
|
||||
"""Check that the set of system calls produced by the I/O stack is what
|
||||
is expected for various read cases.
|
||||
|
||||
It's expected as bits of the I/O implementation change, this will need
|
||||
to change. The goal is to catch changes that unintentionally add
|
||||
additional systemcalls (ex. additional calls have been looked at in
|
||||
bpo-21679 and gh-120754).
|
||||
"""
|
||||
self.f.write(b"Hello, World!")
|
||||
self.f.close()
|
||||
|
||||
|
||||
def check_readall(name, code, prelude="", cleanup=""):
|
||||
with self.subTest(name=name):
|
||||
syscalls = strace_helper.get_syscalls(code, _strace_flags,
|
||||
prelude=prelude,
|
||||
cleanup=cleanup)
|
||||
|
||||
# There are a number of related syscalls used to implement
|
||||
# behaviors in a libc (ex. fstat, newfstatat, open, openat).
|
||||
# Allow any that use the same substring.
|
||||
def count_similarname(name):
|
||||
return len([sc for sc in syscalls if name in sc])
|
||||
|
||||
# Should open and close the file exactly once
|
||||
self.assertEqual(count_similarname('open'), 1)
|
||||
self.assertEqual(count_similarname('close'), 1)
|
||||
|
||||
# Should only have one fstat (bpo-21679, gh-120754)
|
||||
self.assertEqual(count_similarname('fstat'), 1)
|
||||
|
||||
|
||||
# "open, read, close" file using different common patterns.
|
||||
check_readall(
|
||||
"open builtin with default options",
|
||||
f"""
|
||||
f = open('{TESTFN}')
|
||||
f.read()
|
||||
f.close()
|
||||
"""
|
||||
)
|
||||
|
||||
check_readall(
|
||||
"open in binary mode",
|
||||
f"""
|
||||
f = open('{TESTFN}', 'rb')
|
||||
f.read()
|
||||
f.close()
|
||||
"""
|
||||
)
|
||||
|
||||
check_readall(
|
||||
"open in text mode",
|
||||
f"""
|
||||
f = open('{TESTFN}', 'rt')
|
||||
f.read()
|
||||
f.close()
|
||||
"""
|
||||
)
|
||||
|
||||
check_readall(
|
||||
"pathlib read_bytes",
|
||||
"p.read_bytes()",
|
||||
prelude=f"""from pathlib import Path; p = Path("{TESTFN}")"""
|
||||
|
||||
)
|
||||
|
||||
check_readall(
|
||||
"pathlib read_text",
|
||||
"p.read_text()",
|
||||
prelude=f"""from pathlib import Path; p = Path("{TESTFN}")"""
|
||||
)
|
||||
|
||||
# Focus on just `read()`.
|
||||
calls = strace_helper.get_syscalls(
|
||||
prelude=f"f = open('{TESTFN}')",
|
||||
code="f.read()",
|
||||
cleanup="f.close()",
|
||||
strace_flags=_strace_flags
|
||||
)
|
||||
# One to read all the bytes
|
||||
# One to read the EOF and get a size 0 return.
|
||||
self.assertEqual(calls.count("read"), 2)
|
||||
|
||||
|
||||
|
||||
class CAutoFileTests(AutoFileTests, unittest.TestCase):
|
||||
FileIO = _io.FileIO
|
||||
modulename = '_io'
|
||||
|
|
|
|||
|
|
@ -4,7 +4,6 @@ from test import support
|
|||
from test.support import check_sanitizer
|
||||
from test.support import import_helper
|
||||
from test.support import os_helper
|
||||
from test.support import strace_helper
|
||||
from test.support import warnings_helper
|
||||
from test.support.script_helper import assert_python_ok
|
||||
import subprocess
|
||||
|
|
@ -3416,7 +3415,7 @@ class POSIXProcessTestCase(BaseTestCase):
|
|||
|
||||
@unittest.skipIf(not sysconfig.get_config_var("HAVE_VFORK"),
|
||||
"vfork() not enabled by configure.")
|
||||
@strace_helper.requires_strace()
|
||||
@unittest.skipIf(sys.platform != "linux", "Linux only, requires strace.")
|
||||
@mock.patch("subprocess._USE_POSIX_SPAWN", new=False)
|
||||
def test_vfork_used_when_expected(self):
|
||||
# This is a performance regression test to ensure we default to using
|
||||
|
|
@ -3424,25 +3423,36 @@ class POSIXProcessTestCase(BaseTestCase):
|
|||
# Technically this test could pass when posix_spawn is used as well
|
||||
# because libc tends to implement that internally using vfork. But
|
||||
# that'd just be testing a libc+kernel implementation detail.
|
||||
|
||||
# Are intersted in the system calls:
|
||||
# clone,clone2,clone3,fork,vfork,exit,exit_group
|
||||
# Unfortunately using `--trace` with that list to strace fails because
|
||||
# not all are supported on all platforms (ex. clone2 is ia64 only...)
|
||||
# So instead use `%process` which is recommended by strace, and contains
|
||||
# the above.
|
||||
strace_binary = "/usr/bin/strace"
|
||||
# The only system calls we are interested in.
|
||||
strace_filter = "--trace=clone,clone2,clone3,fork,vfork,exit,exit_group"
|
||||
true_binary = "/bin/true"
|
||||
strace_args = ["--trace=%process"]
|
||||
strace_command = [strace_binary, strace_filter]
|
||||
|
||||
try:
|
||||
does_strace_work_process = subprocess.run(
|
||||
strace_command + [true_binary],
|
||||
stderr=subprocess.PIPE,
|
||||
stdout=subprocess.DEVNULL,
|
||||
)
|
||||
rc = does_strace_work_process.returncode
|
||||
stderr = does_strace_work_process.stderr
|
||||
except OSError:
|
||||
rc = -1
|
||||
stderr = ""
|
||||
if rc or (b"+++ exited with 0 +++" not in stderr):
|
||||
self.skipTest("strace not found or not working as expected.")
|
||||
|
||||
with self.subTest(name="default_is_vfork"):
|
||||
vfork_result = strace_helper.strace_python(
|
||||
f"""\
|
||||
import subprocess
|
||||
subprocess.check_call([{true_binary!r}])""",
|
||||
strace_args
|
||||
vfork_result = assert_python_ok(
|
||||
"-c",
|
||||
textwrap.dedent(f"""\
|
||||
import subprocess
|
||||
subprocess.check_call([{true_binary!r}])"""),
|
||||
__run_using_command=strace_command,
|
||||
)
|
||||
# Match both vfork() and clone(..., flags=...|CLONE_VFORK|...)
|
||||
self.assertRegex(vfork_result.event_bytes, br"(?i)vfork")
|
||||
self.assertRegex(vfork_result.err, br"(?i)vfork")
|
||||
# Do NOT check that fork() or other clones did not happen.
|
||||
# If the OS denys the vfork it'll fallback to plain fork().
|
||||
|
||||
|
|
@ -3455,8 +3465,9 @@ class POSIXProcessTestCase(BaseTestCase):
|
|||
("setgroups", "", "extra_groups=[]", True),
|
||||
):
|
||||
with self.subTest(name=sub_name):
|
||||
non_vfork_result = strace_helper.strace_python(
|
||||
f"""\
|
||||
non_vfork_result = assert_python_ok(
|
||||
"-c",
|
||||
textwrap.dedent(f"""\
|
||||
import subprocess
|
||||
{preamble}
|
||||
try:
|
||||
|
|
@ -3464,11 +3475,11 @@ class POSIXProcessTestCase(BaseTestCase):
|
|||
[{true_binary!r}], **dict({sp_kwarg}))
|
||||
except PermissionError:
|
||||
if not {expect_permission_error}:
|
||||
raise""",
|
||||
strace_args
|
||||
raise"""),
|
||||
__run_using_command=strace_command,
|
||||
)
|
||||
# Ensure neither vfork() or clone(..., flags=...|CLONE_VFORK|...).
|
||||
self.assertNotRegex(non_vfork_result.event_bytes, br"(?i)vfork")
|
||||
self.assertNotRegex(non_vfork_result.err, br"(?i)vfork")
|
||||
|
||||
|
||||
@unittest.skipUnless(mswindows, "Windows specific tests")
|
||||
|
|
|
|||
Loading…
Reference in New Issue