From e88a2445bc31dce0caa0be9b543689a953c1f920 Mon Sep 17 00:00:00 2001 From: Richard Oudkerk Date: Tue, 14 Aug 2012 11:41:32 +0100 Subject: Issue #15646: Prevent equivalent of a fork bomb when using multiprocessing on Windows without the "if __name__ == '__main__'" idiom. --- Lib/multiprocessing/forking.py | 2 +- Lib/test/mp_fork_bomb.py | 13 +++++++++++++ Lib/test/test_multiprocessing.py | 23 ++++++++++++++++++++++- Misc/NEWS | 4 ++++ 4 files changed, 40 insertions(+), 2 deletions(-) create mode 100644 Lib/test/mp_fork_bomb.py diff --git a/Lib/multiprocessing/forking.py b/Lib/multiprocessing/forking.py index 4e24d6a..bc8ac44 100644 --- a/Lib/multiprocessing/forking.py +++ b/Lib/multiprocessing/forking.py @@ -331,7 +331,7 @@ else: ''' Returns prefix of command line used for spawning a child process ''' - if process.current_process()._identity==() and is_forking(sys.argv): + if getattr(process.current_process(), '_inheriting', False): raise RuntimeError(''' Attempt to start a new process before the current process has finished its bootstrapping phase. diff --git a/Lib/test/mp_fork_bomb.py b/Lib/test/mp_fork_bomb.py new file mode 100644 index 0000000..908afe3 --- /dev/null +++ b/Lib/test/mp_fork_bomb.py @@ -0,0 +1,13 @@ +import multiprocessing, sys + +def foo(): + print("123") + +# Because "if __name__ == '__main__'" is missing this will not work +# correctly on Windows. However, we should get a RuntimeError rather +# than the Windows equivalent of a fork bomb. + +p = multiprocessing.Process(target=foo) +p.start() +p.join() +sys.exit(p.exitcode) diff --git a/Lib/test/test_multiprocessing.py b/Lib/test/test_multiprocessing.py index 847deb4..ab6d36a 100644 --- a/Lib/test/test_multiprocessing.py +++ b/Lib/test/test_multiprocessing.py @@ -18,6 +18,7 @@ import socket import random import logging import test.support +import test.script_helper # Skip tests if _multiprocessing wasn't built. @@ -2429,9 +2430,29 @@ class TestTimeouts(unittest.TestCase): finally: socket.setdefaulttimeout(old_timeout) +# +# Test what happens with no "if __name__ == '__main__'" +# + +class TestNoForkBomb(unittest.TestCase): + def test_noforkbomb(self): + name = os.path.join(os.path.dirname(__file__), 'mp_fork_bomb.py') + if WIN32: + rc, out, err = test.script_helper.assert_python_failure(name) + self.assertEqual('', out.decode('ascii')) + self.assertIn('RuntimeError', err.decode('ascii')) + else: + rc, out, err = test.script_helper.assert_python_ok(name) + self.assertEqual('123', out.decode('ascii').rstrip()) + self.assertEqual('', err.decode('ascii')) + +# +# +# + testcases_other = [OtherTest, TestInvalidHandle, TestInitializers, TestStdinBadfiledescriptor, TestInvalidFamily, - TestTimeouts] + TestTimeouts, TestNoForkBomb] # # diff --git a/Misc/NEWS b/Misc/NEWS index 30e6b96..5d69e95 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -101,6 +101,10 @@ Core and Builtins Library ------- +- Issue #15646: Prevent equivalent of a fork bomb when using + multiprocessing on Windows without the "if __name__ == '__main__'" + idiom. + - Issue #15424: Add a __sizeof__ implementation for array objects. Patch by Ludwig Hähne. -- cgit v0.12 ?h=v4.7.0&id=ea0f3f7db1d62b2ee94addbeb991061bc2811745'>src/snippets/qstring/stringbuilder.cpp
blob: 92dea599aacdcb8ac58a7ca6078635d3c78870c5 (plain) 
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/****************************************************************************
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//! [0]
    QString foo;
    QString type = "long";

    foo->setText(QLatin1String("vector<") + type + QLatin1String(">::iterator"));

    if (foo.startsWith("(" + type + ") 0x"))
        ...
//! [0]

//! [3]
    #define QT_USE_FAST_CONCATENATION
//! [3]

//! [4]
    #define QT_USE_FAST_CONCATENATION
    #define QT_USE_FAST_OPERATOR_PLUS
//! [4]

//! [5]
    #include <QStringBuilder>

    QString hello("hello");
    QStringRef el(&hello, 2, 3);
    QLatin1String world("world");
    QString message =  hello % el % world % QChar('!');
//! [5]
generated by cgit v0.12 at 2025-10-24 04:11:49 (GMT)