From 6ca622222193bc29a2780f6f02f0d8b96da65a4b Mon Sep 17 00:00:00 2001 From: Kevin Buettner Date: Tue, 19 Feb 2019 13:18:17 -0700 Subject: [PATCH] Use Python 2.[67] / 3.X / PEP 3118 buffer protocol This patch removes the non-IS_PY3K code in infpy_write_memory() and infpy_search_memory(). In both cases, the remaining code from these ifdefs is related to use of the PEP 3118 buffer protocol. (Deleted code is either due to simplification or related to use of the old buffer protocol.) PEP 3118 is sometimes referred to as the "new" buffer protocol, though it's not that new anymore. The link below describes new features in Python 2.6. In particular, it says that the buffer protocol described by PEP 3118 is in Python 2.6. It also says (at the top of the page) that Python 2.6 was released on Oct 1, 2008. https://docs.python.org/3/whatsnew/2.6.html#pep-3118-revised-buffer-protocol The last security release for the Python 2.6 series was 2.6.9. It was released on Oct 29, 2013. According to this document... https://www.python.org/download/releases/2.6.9/ ...support for the 2.6 series has ended: With the 2.6.9 release, and five years after its first release, the Python 2.6 series is now officially retired. All official maintenance for Python 2.6, including security patches, has ended. For ongoing maintenance releases, please see the Python 2.7 series. As noted earlier, Python 2.6, Python 2.7, and Python 3.X all have support for the PEP 3118 buffer protocol. Python releases prior to 2.6 use an older buffer protocol. Since Python 2.6 has been retired for a good while now, it seems reasonable to me to remove code using the older buffer protocol from GDB. I have also simplified some of the code via use of the Py_buffer unique_ptr specialization which I introduced in the two argument gdb.Value constructor patch series. Therefore, there is a dependency on patch #1 from that series. I have tested against both Python 2.7.15 and 3.7.2. I see no regressions among the non-racy tests. I've also verified that PyBuffer_Release is being called when the affected functions exit while running the tests in gdb.python/py-inferior.exp by hand. I've also tried running valgrind on GDB while running this test, but I'm puzzled by the results that I'm seeing - I'm seeing no additional leaks when I comment out the Py_buffer_up lines that I introduced. That said, I'm not seeing any leaks that obviously originate from either infpy_write_memory() or infpy_search_memory(). gdb/ChangeLog: * python/py-inferior.c (infpy_write_memory): Remove non-IS_PY3K code from these functions. Remove corresponding ifdefs. Use Py_buffer_up instead of explicit calls to PyBuffer_Release. Remove gotos and target of gotos. (infpy_search_memory): Likewise. --- gdb/ChangeLog | 8 ++++++ gdb/python/py-inferior.c | 64 ++++++------------------------------------------ 2 files changed, 16 insertions(+), 56 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 2006a02..fe44394 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,11 @@ +2019-02-27 Kevin Buettner + + * python/py-inferior.c (infpy_write_memory): Remove non-IS_PY3K + code from these functions. Remove corresponding ifdefs. Use + Py_buffer_up instead of explicit calls to PyBuffer_Release. + Remove gotos and target of gotos. + (infpy_search_memory): Likewise. + 2019-02-27 Andrew Burgess * gdb/hppa-tdep.c (hppa_dummy_id): Delete. diff --git a/gdb/python/py-inferior.c b/gdb/python/py-inferior.c index 24fc5e6..ba769b3 100644 --- a/gdb/python/py-inferior.c +++ b/gdb/python/py-inferior.c @@ -554,31 +554,23 @@ infpy_write_memory (PyObject *self, PyObject *args, PyObject *kw) CORE_ADDR addr, length; PyObject *addr_obj, *length_obj = NULL; static const char *keywords[] = { "address", "buffer", "length", NULL }; -#ifdef IS_PY3K Py_buffer pybuf; if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "Os*|O", keywords, &addr_obj, &pybuf, &length_obj)) return NULL; + Py_buffer_up buffer_up (&pybuf); buffer = (const gdb_byte *) pybuf.buf; buf_len = pybuf.len; -#else - if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "Os#|O", keywords, - &addr_obj, &buffer, &buf_len, - &length_obj)) - return NULL; - - buffer = (const gdb_byte *) buffer; -#endif if (get_addr_from_python (addr_obj, &addr) < 0) - goto fail; + return nullptr; if (!length_obj) length = buf_len; else if (get_addr_from_python (length_obj, &length) < 0) - goto fail; + return nullptr; TRY { @@ -590,18 +582,9 @@ infpy_write_memory (PyObject *self, PyObject *args, PyObject *kw) } END_CATCH -#ifdef IS_PY3K - PyBuffer_Release (&pybuf); -#endif GDB_PY_HANDLE_EXCEPTION (except); Py_RETURN_NONE; - - fail: -#ifdef IS_PY3K - PyBuffer_Release (&pybuf); -#endif - return NULL; } /* Destructor of Membuf objects. */ @@ -710,7 +693,6 @@ infpy_search_memory (PyObject *self, PyObject *args, PyObject *kw) const gdb_byte *buffer; CORE_ADDR found_addr; int found = 0; -#ifdef IS_PY3K Py_buffer pybuf; if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "OOs*", keywords, @@ -718,42 +700,21 @@ infpy_search_memory (PyObject *self, PyObject *args, PyObject *kw) &pybuf)) return NULL; + Py_buffer_up buffer_up (&pybuf); buffer = (const gdb_byte *) pybuf.buf; pattern_size = pybuf.len; -#else - PyObject *pattern; - const void *vbuffer; - - if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "OOO", keywords, - &start_addr_obj, &length_obj, - &pattern)) - return NULL; - - if (!PyObject_CheckReadBuffer (pattern)) - { - PyErr_SetString (PyExc_RuntimeError, - _("The pattern is not a Python buffer.")); - - return NULL; - } - - if (PyObject_AsReadBuffer (pattern, &vbuffer, &pattern_size) == -1) - return NULL; - - buffer = (const gdb_byte *) vbuffer; -#endif if (get_addr_from_python (start_addr_obj, &start_addr) < 0) - goto fail; + return nullptr; if (get_addr_from_python (length_obj, &length) < 0) - goto fail; + return nullptr; if (!length) { PyErr_SetString (PyExc_ValueError, _("Search range is empty.")); - goto fail; + return nullptr; } /* Watch for overflows. */ else if (length > CORE_ADDR_MAX @@ -761,7 +722,7 @@ infpy_search_memory (PyObject *self, PyObject *args, PyObject *kw) { PyErr_SetString (PyExc_ValueError, _("The search range is too large.")); - goto fail; + return nullptr; } TRY @@ -776,21 +737,12 @@ infpy_search_memory (PyObject *self, PyObject *args, PyObject *kw) } END_CATCH -#ifdef IS_PY3K - PyBuffer_Release (&pybuf); -#endif GDB_PY_HANDLE_EXCEPTION (except); if (found) return PyLong_FromLong (found_addr); else Py_RETURN_NONE; - - fail: -#ifdef IS_PY3K - PyBuffer_Release (&pybuf); -#endif - return NULL; } /* Implementation of gdb.Inferior.is_valid (self) -> Boolean. -- 2.7.4