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ai-content-maker/.venv/Lib/site-packages/Cython/Debugger/libpython.py

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2024-05-03 04:18:51 +03:00
#!/usr/bin/python
# NOTE: Most of this file is taken from the Python source distribution
# It can be found under Tools/gdb/libpython.py. It is shipped with Cython
# because it's not installed as a python module, and because changes are only
# merged into new python versions (v3.2+).
# We added some of our code below the "## added, not in CPython" comment.
'''
From gdb 7 onwards, gdb's build can be configured --with-python, allowing gdb
to be extended with Python code e.g. for library-specific data visualizations,
such as for the C++ STL types. Documentation on this API can be seen at:
http://sourceware.org/gdb/current/onlinedocs/gdb/Python-API.html
This python module deals with the case when the process being debugged (the
"inferior process" in gdb parlance) is itself python, or more specifically,
linked against libpython. In this situation, almost every item of data is a
(PyObject*), and having the debugger merely print their addresses is not very
enlightening.
This module embeds knowledge about the implementation details of libpython so
that we can emit useful visualizations e.g. a string, a list, a dict, a frame
giving file/line information and the state of local variables
In particular, given a gdb.Value corresponding to a PyObject* in the inferior
process, we can generate a "proxy value" within the gdb process. For example,
given a PyObject* in the inferior process that is in fact a PyListObject*
holding three PyObject* that turn out to be PyBytesObject* instances, we can
generate a proxy value within the gdb process that is a list of bytes
instances:
[b"foo", b"bar", b"baz"]
Doing so can be expensive for complicated graphs of objects, and could take
some time, so we also have a "write_repr" method that writes a representation
of the data to a file-like object. This allows us to stop the traversal by
having the file-like object raise an exception if it gets too much data.
With both "proxyval" and "write_repr" we keep track of the set of all addresses
visited so far in the traversal, to avoid infinite recursion due to cycles in
the graph of object references.
We try to defer gdb.lookup_type() invocations for python types until as late as
possible: for a dynamically linked python binary, when the process starts in
the debugger, the libpython.so hasn't been dynamically loaded yet, so none of
the type names are known to the debugger
The module also extends gdb with some python-specific commands.
'''
# NOTE: some gdbs are linked with Python 3, so this file should be dual-syntax
# compatible (2.6+ and 3.0+). See #19308.
from __future__ import print_function
import gdb
import os
import locale
import sys
if sys.version_info[0] >= 3:
unichr = chr
xrange = range
long = int
# Look up the gdb.Type for some standard types:
# Those need to be refreshed as types (pointer sizes) may change when
# gdb loads different executables
def _type_char_ptr():
return gdb.lookup_type('char').pointer() # char*
def _type_unsigned_char_ptr():
return gdb.lookup_type('unsigned char').pointer() # unsigned char*
def _type_unsigned_short_ptr():
return gdb.lookup_type('unsigned short').pointer()
def _type_unsigned_int_ptr():
return gdb.lookup_type('unsigned int').pointer()
def _sizeof_void_p():
return gdb.lookup_type('void').pointer().sizeof
# value computed later, see PyUnicodeObjectPtr.proxy()
_is_pep393 = None
Py_TPFLAGS_HEAPTYPE = (1 << 9)
Py_TPFLAGS_LONG_SUBCLASS = (1 << 24)
Py_TPFLAGS_LIST_SUBCLASS = (1 << 25)
Py_TPFLAGS_TUPLE_SUBCLASS = (1 << 26)
Py_TPFLAGS_BYTES_SUBCLASS = (1 << 27)
Py_TPFLAGS_UNICODE_SUBCLASS = (1 << 28)
Py_TPFLAGS_DICT_SUBCLASS = (1 << 29)
Py_TPFLAGS_BASE_EXC_SUBCLASS = (1 << 30)
Py_TPFLAGS_TYPE_SUBCLASS = (1 << 31)
MAX_OUTPUT_LEN=1024
hexdigits = "0123456789abcdef"
ENCODING = locale.getpreferredencoding()
FRAME_INFO_OPTIMIZED_OUT = '(frame information optimized out)'
UNABLE_READ_INFO_PYTHON_FRAME = 'Unable to read information on python frame'
EVALFRAME = '_PyEval_EvalFrameDefault'
class NullPyObjectPtr(RuntimeError):
pass
def safety_limit(val):
# Given an integer value from the process being debugged, limit it to some
# safety threshold so that arbitrary breakage within said process doesn't
# break the gdb process too much (e.g. sizes of iterations, sizes of lists)
return min(val, 1000)
def safe_range(val):
# As per range, but don't trust the value too much: cap it to a safety
# threshold in case the data was corrupted
return xrange(safety_limit(int(val)))
if sys.version_info[0] >= 3:
def write_unicode(file, text):
file.write(text)
else:
def write_unicode(file, text):
# Write a byte or unicode string to file. Unicode strings are encoded to
# ENCODING encoding with 'backslashreplace' error handler to avoid
# UnicodeEncodeError.
if isinstance(text, unicode):
text = text.encode(ENCODING, 'backslashreplace')
file.write(text)
try:
os_fsencode = os.fsencode
except AttributeError:
def os_fsencode(filename):
if not isinstance(filename, unicode):
return filename
encoding = sys.getfilesystemencoding()
if encoding == 'mbcs':
# mbcs doesn't support surrogateescape
return filename.encode(encoding)
encoded = []
for char in filename:
# surrogateescape error handler
if 0xDC80 <= ord(char) <= 0xDCFF:
byte = chr(ord(char) - 0xDC00)
else:
byte = char.encode(encoding)
encoded.append(byte)
return ''.join(encoded)
class StringTruncated(RuntimeError):
pass
class TruncatedStringIO(object):
'''Similar to io.StringIO, but can truncate the output by raising a
StringTruncated exception'''
def __init__(self, maxlen=None):
self._val = ''
self.maxlen = maxlen
def write(self, data):
if self.maxlen:
if len(data) + len(self._val) > self.maxlen:
# Truncation:
self._val += data[0:self.maxlen - len(self._val)]
raise StringTruncated()
self._val += data
def getvalue(self):
return self._val
class PyObjectPtr(object):
"""
Class wrapping a gdb.Value that's either a (PyObject*) within the
inferior process, or some subclass pointer e.g. (PyBytesObject*)
There will be a subclass for every refined PyObject type that we care
about.
Note that at every stage the underlying pointer could be NULL, point
to corrupt data, etc; this is the debugger, after all.
"""
_typename = 'PyObject'
def __init__(self, gdbval, cast_to=None):
if cast_to:
self._gdbval = gdbval.cast(cast_to)
else:
self._gdbval = gdbval
def field(self, name):
'''
Get the gdb.Value for the given field within the PyObject, coping with
some python 2 versus python 3 differences.
Various libpython types are defined using the "PyObject_HEAD" and
"PyObject_VAR_HEAD" macros.
In Python 2, this these are defined so that "ob_type" and (for a var
object) "ob_size" are fields of the type in question.
In Python 3, this is defined as an embedded PyVarObject type thus:
PyVarObject ob_base;
so that the "ob_size" field is located insize the "ob_base" field, and
the "ob_type" is most easily accessed by casting back to a (PyObject*).
'''
if self.is_null():
raise NullPyObjectPtr(self)
if name == 'ob_type':
pyo_ptr = self._gdbval.cast(PyObjectPtr.get_gdb_type())
return pyo_ptr.dereference()[name]
if name == 'ob_size':
pyo_ptr = self._gdbval.cast(PyVarObjectPtr.get_gdb_type())
return pyo_ptr.dereference()[name]
# General case: look it up inside the object:
return self._gdbval.dereference()[name]
def pyop_field(self, name):
'''
Get a PyObjectPtr for the given PyObject* field within this PyObject,
coping with some python 2 versus python 3 differences.
'''
return PyObjectPtr.from_pyobject_ptr(self.field(name))
def write_field_repr(self, name, out, visited):
'''
Extract the PyObject* field named "name", and write its representation
to file-like object "out"
'''
field_obj = self.pyop_field(name)
field_obj.write_repr(out, visited)
def get_truncated_repr(self, maxlen):
'''
Get a repr-like string for the data, but truncate it at "maxlen" bytes
(ending the object graph traversal as soon as you do)
'''
out = TruncatedStringIO(maxlen)
try:
self.write_repr(out, set())
except StringTruncated:
# Truncation occurred:
return out.getvalue() + '...(truncated)'
# No truncation occurred:
return out.getvalue()
def type(self):
return PyTypeObjectPtr(self.field('ob_type'))
def is_null(self):
return 0 == long(self._gdbval)
def is_optimized_out(self):
'''
Is the value of the underlying PyObject* visible to the debugger?
This can vary with the precise version of the compiler used to build
Python, and the precise version of gdb.
See e.g. https://bugzilla.redhat.com/show_bug.cgi?id=556975 with
PyEval_EvalFrameEx's "f"
'''
return self._gdbval.is_optimized_out
def safe_tp_name(self):
try:
ob_type = self.type()
tp_name = ob_type.field('tp_name')
return tp_name.string()
# NullPyObjectPtr: NULL tp_name?
# RuntimeError: Can't even read the object at all?
# UnicodeDecodeError: Failed to decode tp_name bytestring
except (NullPyObjectPtr, RuntimeError, UnicodeDecodeError):
return 'unknown'
def proxyval(self, visited):
'''
Scrape a value from the inferior process, and try to represent it
within the gdb process, whilst (hopefully) avoiding crashes when
the remote data is corrupt.
Derived classes will override this.
For example, a PyIntObject* with ob_ival 42 in the inferior process
should result in an int(42) in this process.
visited: a set of all gdb.Value pyobject pointers already visited
whilst generating this value (to guard against infinite recursion when
visiting object graphs with loops). Analogous to Py_ReprEnter and
Py_ReprLeave
'''
class FakeRepr(object):
"""
Class representing a non-descript PyObject* value in the inferior
process for when we don't have a custom scraper, intended to have
a sane repr().
"""
def __init__(self, tp_name, address):
self.tp_name = tp_name
self.address = address
def __repr__(self):
# For the NULL pointer, we have no way of knowing a type, so
# special-case it as per
# http://bugs.python.org/issue8032#msg100882
if self.address == 0:
return '0x0'
return '<%s at remote 0x%x>' % (self.tp_name, self.address)
return FakeRepr(self.safe_tp_name(),
long(self._gdbval))
def write_repr(self, out, visited):
'''
Write a string representation of the value scraped from the inferior
process to "out", a file-like object.
'''
# Default implementation: generate a proxy value and write its repr
# However, this could involve a lot of work for complicated objects,
# so for derived classes we specialize this
return out.write(repr(self.proxyval(visited)))
@classmethod
def subclass_from_type(cls, t):
'''
Given a PyTypeObjectPtr instance wrapping a gdb.Value that's a
(PyTypeObject*), determine the corresponding subclass of PyObjectPtr
to use
Ideally, we would look up the symbols for the global types, but that
isn't working yet:
(gdb) python print gdb.lookup_symbol('PyList_Type')[0].value
Traceback (most recent call last):
File "<string>", line 1, in <module>
NotImplementedError: Symbol type not yet supported in Python scripts.
Error while executing Python code.
For now, we use tp_flags, after doing some string comparisons on the
tp_name for some special-cases that don't seem to be visible through
flags
'''
try:
tp_name = t.field('tp_name').string()
tp_flags = int(t.field('tp_flags'))
# RuntimeError: NULL pointers
# UnicodeDecodeError: string() fails to decode the bytestring
except (RuntimeError, UnicodeDecodeError):
# Handle any kind of error e.g. NULL ptrs by simply using the base
# class
return cls
#print('tp_flags = 0x%08x' % tp_flags)
#print('tp_name = %r' % tp_name)
name_map = {'bool': PyBoolObjectPtr,
'classobj': PyClassObjectPtr,
'NoneType': PyNoneStructPtr,
'frame': PyFrameObjectPtr,
'set' : PySetObjectPtr,
'frozenset' : PySetObjectPtr,
'builtin_function_or_method' : PyCFunctionObjectPtr,
'method-wrapper': wrapperobject,
}
if tp_name in name_map:
return name_map[tp_name]
if tp_flags & Py_TPFLAGS_HEAPTYPE:
return HeapTypeObjectPtr
if tp_flags & Py_TPFLAGS_LONG_SUBCLASS:
return PyLongObjectPtr
if tp_flags & Py_TPFLAGS_LIST_SUBCLASS:
return PyListObjectPtr
if tp_flags & Py_TPFLAGS_TUPLE_SUBCLASS:
return PyTupleObjectPtr
if tp_flags & Py_TPFLAGS_BYTES_SUBCLASS:
return PyBytesObjectPtr
if tp_flags & Py_TPFLAGS_UNICODE_SUBCLASS:
return PyUnicodeObjectPtr
if tp_flags & Py_TPFLAGS_DICT_SUBCLASS:
return PyDictObjectPtr
if tp_flags & Py_TPFLAGS_BASE_EXC_SUBCLASS:
return PyBaseExceptionObjectPtr
#if tp_flags & Py_TPFLAGS_TYPE_SUBCLASS:
# return PyTypeObjectPtr
# Use the base class:
return cls
@classmethod
def from_pyobject_ptr(cls, gdbval):
'''
Try to locate the appropriate derived class dynamically, and cast
the pointer accordingly.
'''
try:
p = PyObjectPtr(gdbval)
cls = cls.subclass_from_type(p.type())
return cls(gdbval, cast_to=cls.get_gdb_type())
except RuntimeError:
# Handle any kind of error e.g. NULL ptrs by simply using the base
# class
pass
return cls(gdbval)
@classmethod
def get_gdb_type(cls):
return gdb.lookup_type(cls._typename).pointer()
def as_address(self):
return long(self._gdbval)
class PyVarObjectPtr(PyObjectPtr):
_typename = 'PyVarObject'
class ProxyAlreadyVisited(object):
'''
Placeholder proxy to use when protecting against infinite recursion due to
loops in the object graph.
Analogous to the values emitted by the users of Py_ReprEnter and Py_ReprLeave
'''
def __init__(self, rep):
self._rep = rep
def __repr__(self):
return self._rep
def _write_instance_repr(out, visited, name, pyop_attrdict, address):
'''Shared code for use by all classes:
write a representation to file-like object "out"'''
out.write('<')
out.write(name)
# Write dictionary of instance attributes:
if isinstance(pyop_attrdict, PyDictObjectPtr):
out.write('(')
first = True
for pyop_arg, pyop_val in pyop_attrdict.iteritems():
if not first:
out.write(', ')
first = False
out.write(pyop_arg.proxyval(visited))
out.write('=')
pyop_val.write_repr(out, visited)
out.write(')')
out.write(' at remote 0x%x>' % address)
class InstanceProxy(object):
def __init__(self, cl_name, attrdict, address):
self.cl_name = cl_name
self.attrdict = attrdict
self.address = address
def __repr__(self):
if isinstance(self.attrdict, dict):
kwargs = ', '.join(["%s=%r" % (arg, val)
for arg, val in self.attrdict.iteritems()])
return '<%s(%s) at remote 0x%x>' % (self.cl_name,
kwargs, self.address)
else:
return '<%s at remote 0x%x>' % (self.cl_name,
self.address)
def _PyObject_VAR_SIZE(typeobj, nitems):
if _PyObject_VAR_SIZE._type_size_t is None:
_PyObject_VAR_SIZE._type_size_t = gdb.lookup_type('size_t')
return ( ( typeobj.field('tp_basicsize') +
nitems * typeobj.field('tp_itemsize') +
(_sizeof_void_p() - 1)
) & ~(_sizeof_void_p() - 1)
).cast(_PyObject_VAR_SIZE._type_size_t)
_PyObject_VAR_SIZE._type_size_t = None
class HeapTypeObjectPtr(PyObjectPtr):
_typename = 'PyObject'
def get_attr_dict(self):
'''
Get the PyDictObject ptr representing the attribute dictionary
(or None if there's a problem)
'''
try:
typeobj = self.type()
dictoffset = int_from_int(typeobj.field('tp_dictoffset'))
if dictoffset != 0:
if dictoffset < 0:
type_PyVarObject_ptr = gdb.lookup_type('PyVarObject').pointer()
tsize = int_from_int(self._gdbval.cast(type_PyVarObject_ptr)['ob_size'])
if tsize < 0:
tsize = -tsize
size = _PyObject_VAR_SIZE(typeobj, tsize)
dictoffset += size
assert dictoffset > 0
assert dictoffset % _sizeof_void_p() == 0
dictptr = self._gdbval.cast(_type_char_ptr()) + dictoffset
PyObjectPtrPtr = PyObjectPtr.get_gdb_type().pointer()
dictptr = dictptr.cast(PyObjectPtrPtr)
return PyObjectPtr.from_pyobject_ptr(dictptr.dereference())
except RuntimeError:
# Corrupt data somewhere; fail safe
pass
# Not found, or some kind of error:
return None
def proxyval(self, visited):
'''
Support for classes.
Currently we just locate the dictionary using a transliteration to
python of _PyObject_GetDictPtr, ignoring descriptors
'''
# Guard against infinite loops:
if self.as_address() in visited:
return ProxyAlreadyVisited('<...>')
visited.add(self.as_address())
pyop_attr_dict = self.get_attr_dict()
if pyop_attr_dict:
attr_dict = pyop_attr_dict.proxyval(visited)
else:
attr_dict = {}
tp_name = self.safe_tp_name()
# Class:
return InstanceProxy(tp_name, attr_dict, long(self._gdbval))
def write_repr(self, out, visited):
# Guard against infinite loops:
if self.as_address() in visited:
out.write('<...>')
return
visited.add(self.as_address())
pyop_attrdict = self.get_attr_dict()
_write_instance_repr(out, visited,
self.safe_tp_name(), pyop_attrdict, self.as_address())
class ProxyException(Exception):
def __init__(self, tp_name, args):
self.tp_name = tp_name
self.args = args
def __repr__(self):
return '%s%r' % (self.tp_name, self.args)
class PyBaseExceptionObjectPtr(PyObjectPtr):
"""
Class wrapping a gdb.Value that's a PyBaseExceptionObject* i.e. an exception
within the process being debugged.
"""
_typename = 'PyBaseExceptionObject'
def proxyval(self, visited):
# Guard against infinite loops:
if self.as_address() in visited:
return ProxyAlreadyVisited('(...)')
visited.add(self.as_address())
arg_proxy = self.pyop_field('args').proxyval(visited)
return ProxyException(self.safe_tp_name(),
arg_proxy)
def write_repr(self, out, visited):
# Guard against infinite loops:
if self.as_address() in visited:
out.write('(...)')
return
visited.add(self.as_address())
out.write(self.safe_tp_name())
self.write_field_repr('args', out, visited)
class PyClassObjectPtr(PyObjectPtr):
"""
Class wrapping a gdb.Value that's a PyClassObject* i.e. a <classobj>
instance within the process being debugged.
"""
_typename = 'PyClassObject'
class BuiltInFunctionProxy(object):
def __init__(self, ml_name):
self.ml_name = ml_name
def __repr__(self):
return "<built-in function %s>" % self.ml_name
class BuiltInMethodProxy(object):
def __init__(self, ml_name, pyop_m_self):
self.ml_name = ml_name
self.pyop_m_self = pyop_m_self
def __repr__(self):
return ('<built-in method %s of %s object at remote 0x%x>'
% (self.ml_name,
self.pyop_m_self.safe_tp_name(),
self.pyop_m_self.as_address())
)
class PyCFunctionObjectPtr(PyObjectPtr):
"""
Class wrapping a gdb.Value that's a PyCFunctionObject*
(see Include/methodobject.h and Objects/methodobject.c)
"""
_typename = 'PyCFunctionObject'
def proxyval(self, visited):
m_ml = self.field('m_ml') # m_ml is a (PyMethodDef*)
try:
ml_name = m_ml['ml_name'].string()
except UnicodeDecodeError:
ml_name = '<ml_name:UnicodeDecodeError>'
pyop_m_self = self.pyop_field('m_self')
if pyop_m_self.is_null():
return BuiltInFunctionProxy(ml_name)
else:
return BuiltInMethodProxy(ml_name, pyop_m_self)
class PyCodeObjectPtr(PyObjectPtr):
"""
Class wrapping a gdb.Value that's a PyCodeObject* i.e. a <code> instance
within the process being debugged.
"""
_typename = 'PyCodeObject'
def addr2line(self, addrq):
'''
Get the line number for a given bytecode offset
Analogous to PyCode_Addr2Line; translated from pseudocode in
Objects/lnotab_notes.txt
'''
co_lnotab = self.pyop_field('co_lnotab').proxyval(set())
# Initialize lineno to co_firstlineno as per PyCode_Addr2Line
# not 0, as lnotab_notes.txt has it:
lineno = int_from_int(self.field('co_firstlineno'))
addr = 0
for addr_incr, line_incr in zip(co_lnotab[::2], co_lnotab[1::2]):
addr += ord(addr_incr)
if addr > addrq:
return lineno
lineno += ord(line_incr)
return lineno
class PyDictObjectPtr(PyObjectPtr):
"""
Class wrapping a gdb.Value that's a PyDictObject* i.e. a dict instance
within the process being debugged.
"""
_typename = 'PyDictObject'
def iteritems(self):
'''
Yields a sequence of (PyObjectPtr key, PyObjectPtr value) pairs,
analogous to dict.iteritems()
'''
keys = self.field('ma_keys')
values = self.field('ma_values')
entries, nentries = self._get_entries(keys)
for i in safe_range(nentries):
ep = entries[i]
if long(values):
pyop_value = PyObjectPtr.from_pyobject_ptr(values[i])
else:
pyop_value = PyObjectPtr.from_pyobject_ptr(ep['me_value'])
if not pyop_value.is_null():
pyop_key = PyObjectPtr.from_pyobject_ptr(ep['me_key'])
yield (pyop_key, pyop_value)
def proxyval(self, visited):
# Guard against infinite loops:
if self.as_address() in visited:
return ProxyAlreadyVisited('{...}')
visited.add(self.as_address())
result = {}
for pyop_key, pyop_value in self.iteritems():
proxy_key = pyop_key.proxyval(visited)
proxy_value = pyop_value.proxyval(visited)
result[proxy_key] = proxy_value
return result
def write_repr(self, out, visited):
# Guard against infinite loops:
if self.as_address() in visited:
out.write('{...}')
return
visited.add(self.as_address())
out.write('{')
first = True
for pyop_key, pyop_value in self.iteritems():
if not first:
out.write(', ')
first = False
pyop_key.write_repr(out, visited)
out.write(': ')
pyop_value.write_repr(out, visited)
out.write('}')
def _get_entries(self, keys):
dk_nentries = int(keys['dk_nentries'])
dk_size = int(keys['dk_size'])
try:
# <= Python 3.5
return keys['dk_entries'], dk_size
except RuntimeError:
# >= Python 3.6
pass
if dk_size <= 0xFF:
offset = dk_size
elif dk_size <= 0xFFFF:
offset = 2 * dk_size
elif dk_size <= 0xFFFFFFFF:
offset = 4 * dk_size
else:
offset = 8 * dk_size
ent_addr = keys['dk_indices'].address
ent_addr = ent_addr.cast(_type_unsigned_char_ptr()) + offset
ent_ptr_t = gdb.lookup_type('PyDictKeyEntry').pointer()
ent_addr = ent_addr.cast(ent_ptr_t)
return ent_addr, dk_nentries
class PyListObjectPtr(PyObjectPtr):
_typename = 'PyListObject'
def __getitem__(self, i):
# Get the gdb.Value for the (PyObject*) with the given index:
field_ob_item = self.field('ob_item')
return field_ob_item[i]
def proxyval(self, visited):
# Guard against infinite loops:
if self.as_address() in visited:
return ProxyAlreadyVisited('[...]')
visited.add(self.as_address())
result = [PyObjectPtr.from_pyobject_ptr(self[i]).proxyval(visited)
for i in safe_range(int_from_int(self.field('ob_size')))]
return result
def write_repr(self, out, visited):
# Guard against infinite loops:
if self.as_address() in visited:
out.write('[...]')
return
visited.add(self.as_address())
out.write('[')
for i in safe_range(int_from_int(self.field('ob_size'))):
if i > 0:
out.write(', ')
element = PyObjectPtr.from_pyobject_ptr(self[i])
element.write_repr(out, visited)
out.write(']')
class PyLongObjectPtr(PyObjectPtr):
_typename = 'PyLongObject'
def proxyval(self, visited):
'''
Python's Include/longobjrep.h has this declaration:
struct _longobject {
PyObject_VAR_HEAD
digit ob_digit[1];
};
with this description:
The absolute value of a number is equal to
SUM(for i=0 through abs(ob_size)-1) ob_digit[i] * 2**(SHIFT*i)
Negative numbers are represented with ob_size < 0;
zero is represented by ob_size == 0.
where SHIFT can be either:
#define PyLong_SHIFT 30
#define PyLong_SHIFT 15
'''
ob_size = long(self.field('ob_size'))
if ob_size == 0:
return 0
ob_digit = self.field('ob_digit')
if gdb.lookup_type('digit').sizeof == 2:
SHIFT = 15
else:
SHIFT = 30
digits = [long(ob_digit[i]) * 2**(SHIFT*i)
for i in safe_range(abs(ob_size))]
result = sum(digits)
if ob_size < 0:
result = -result
return result
def write_repr(self, out, visited):
# Write this out as a Python 3 int literal, i.e. without the "L" suffix
proxy = self.proxyval(visited)
out.write("%s" % proxy)
class PyBoolObjectPtr(PyLongObjectPtr):
"""
Class wrapping a gdb.Value that's a PyBoolObject* i.e. one of the two
<bool> instances (Py_True/Py_False) within the process being debugged.
"""
def proxyval(self, visited):
if PyLongObjectPtr.proxyval(self, visited):
return True
else:
return False
class PyNoneStructPtr(PyObjectPtr):
"""
Class wrapping a gdb.Value that's a PyObject* pointing to the
singleton (we hope) _Py_NoneStruct with ob_type PyNone_Type
"""
_typename = 'PyObject'
def proxyval(self, visited):
return None
class PyFrameObjectPtr(PyObjectPtr):
_typename = 'PyFrameObject'
def __init__(self, gdbval, cast_to=None):
PyObjectPtr.__init__(self, gdbval, cast_to)
if not self.is_optimized_out():
self.co = PyCodeObjectPtr.from_pyobject_ptr(self.field('f_code'))
self.co_name = self.co.pyop_field('co_name')
self.co_filename = self.co.pyop_field('co_filename')
self.f_lineno = int_from_int(self.field('f_lineno'))
self.f_lasti = int_from_int(self.field('f_lasti'))
self.co_nlocals = int_from_int(self.co.field('co_nlocals'))
self.co_varnames = PyTupleObjectPtr.from_pyobject_ptr(self.co.field('co_varnames'))
def iter_locals(self):
'''
Yield a sequence of (name,value) pairs of PyObjectPtr instances, for
the local variables of this frame
'''
if self.is_optimized_out():
return
f_localsplus = self.field('f_localsplus')
for i in safe_range(self.co_nlocals):
pyop_value = PyObjectPtr.from_pyobject_ptr(f_localsplus[i])
if not pyop_value.is_null():
pyop_name = PyObjectPtr.from_pyobject_ptr(self.co_varnames[i])
yield (pyop_name, pyop_value)
def iter_globals(self):
'''
Yield a sequence of (name,value) pairs of PyObjectPtr instances, for
the global variables of this frame
'''
if self.is_optimized_out():
return ()
pyop_globals = self.pyop_field('f_globals')
return pyop_globals.iteritems()
def iter_builtins(self):
'''
Yield a sequence of (name,value) pairs of PyObjectPtr instances, for
the builtin variables
'''
if self.is_optimized_out():
return ()
pyop_builtins = self.pyop_field('f_builtins')
return pyop_builtins.iteritems()
def get_var_by_name(self, name):
'''
Look for the named local variable, returning a (PyObjectPtr, scope) pair
where scope is a string 'local', 'global', 'builtin'
If not found, return (None, None)
'''
for pyop_name, pyop_value in self.iter_locals():
if name == pyop_name.proxyval(set()):
return pyop_value, 'local'
for pyop_name, pyop_value in self.iter_globals():
if name == pyop_name.proxyval(set()):
return pyop_value, 'global'
for pyop_name, pyop_value in self.iter_builtins():
if name == pyop_name.proxyval(set()):
return pyop_value, 'builtin'
return None, None
def filename(self):
'''Get the path of the current Python source file, as a string'''
if self.is_optimized_out():
return FRAME_INFO_OPTIMIZED_OUT
return self.co_filename.proxyval(set())
def current_line_num(self):
'''Get current line number as an integer (1-based)
Translated from PyFrame_GetLineNumber and PyCode_Addr2Line
See Objects/lnotab_notes.txt
'''
if self.is_optimized_out():
return None
f_trace = self.field('f_trace')
if long(f_trace) != 0:
# we have a non-NULL f_trace:
return self.f_lineno
try:
return self.co.addr2line(self.f_lasti)
except Exception:
# bpo-34989: addr2line() is a complex function, it can fail in many
# ways. For example, it fails with a TypeError on "FakeRepr" if
# gdb fails to load debug symbols. Use a catch-all "except
# Exception" to make the whole function safe. The caller has to
# handle None anyway for optimized Python.
return None
def current_line(self):
'''Get the text of the current source line as a string, with a trailing
newline character'''
if self.is_optimized_out():
return FRAME_INFO_OPTIMIZED_OUT
lineno = self.current_line_num()
if lineno is None:
return '(failed to get frame line number)'
filename = self.filename()
try:
with open(os_fsencode(filename), 'r') as fp:
lines = fp.readlines()
except IOError:
return None
try:
# Convert from 1-based current_line_num to 0-based list offset
return lines[lineno - 1]
except IndexError:
return None
def write_repr(self, out, visited):
if self.is_optimized_out():
out.write(FRAME_INFO_OPTIMIZED_OUT)
return
lineno = self.current_line_num()
lineno = str(lineno) if lineno is not None else "?"
out.write('Frame 0x%x, for file %s, line %s, in %s ('
% (self.as_address(),
self.co_filename.proxyval(visited),
lineno,
self.co_name.proxyval(visited)))
first = True
for pyop_name, pyop_value in self.iter_locals():
if not first:
out.write(', ')
first = False
out.write(pyop_name.proxyval(visited))
out.write('=')
pyop_value.write_repr(out, visited)
out.write(')')
def print_traceback(self):
if self.is_optimized_out():
sys.stdout.write(' %s\n' % FRAME_INFO_OPTIMIZED_OUT)
return
visited = set()
lineno = self.current_line_num()
lineno = str(lineno) if lineno is not None else "?"
sys.stdout.write(' File "%s", line %s, in %s\n'
% (self.co_filename.proxyval(visited),
lineno,
self.co_name.proxyval(visited)))
class PySetObjectPtr(PyObjectPtr):
_typename = 'PySetObject'
@classmethod
def _dummy_key(self):
return gdb.lookup_global_symbol('_PySet_Dummy').value()
def __iter__(self):
dummy_ptr = self._dummy_key()
table = self.field('table')
for i in safe_range(self.field('mask') + 1):
setentry = table[i]
key = setentry['key']
if key != 0 and key != dummy_ptr:
yield PyObjectPtr.from_pyobject_ptr(key)
def proxyval(self, visited):
# Guard against infinite loops:
if self.as_address() in visited:
return ProxyAlreadyVisited('%s(...)' % self.safe_tp_name())
visited.add(self.as_address())
members = (key.proxyval(visited) for key in self)
if self.safe_tp_name() == 'frozenset':
return frozenset(members)
else:
return set(members)
def write_repr(self, out, visited):
# Emulate Python 3's set_repr
tp_name = self.safe_tp_name()
# Guard against infinite loops:
if self.as_address() in visited:
out.write('(...)')
return
visited.add(self.as_address())
# Python 3's set_repr special-cases the empty set:
if not self.field('used'):
out.write(tp_name)
out.write('()')
return
# Python 3 uses {} for set literals:
if tp_name != 'set':
out.write(tp_name)
out.write('(')
out.write('{')
first = True
for key in self:
if not first:
out.write(', ')
first = False
key.write_repr(out, visited)
out.write('}')
if tp_name != 'set':
out.write(')')
class PyBytesObjectPtr(PyObjectPtr):
_typename = 'PyBytesObject'
def __str__(self):
field_ob_size = self.field('ob_size')
field_ob_sval = self.field('ob_sval')
char_ptr = field_ob_sval.address.cast(_type_unsigned_char_ptr())
return ''.join([chr(char_ptr[i]) for i in safe_range(field_ob_size)])
def proxyval(self, visited):
return str(self)
def write_repr(self, out, visited):
# Write this out as a Python 3 bytes literal, i.e. with a "b" prefix
# Get a PyStringObject* within the Python 2 gdb process:
proxy = self.proxyval(visited)
# Transliteration of Python 3's Objects/bytesobject.c:PyBytes_Repr
# to Python 2 code:
quote = "'"
if "'" in proxy and not '"' in proxy:
quote = '"'
out.write('b')
out.write(quote)
for byte in proxy:
if byte == quote or byte == '\\':
out.write('\\')
out.write(byte)
elif byte == '\t':
out.write('\\t')
elif byte == '\n':
out.write('\\n')
elif byte == '\r':
out.write('\\r')
elif byte < ' ' or ord(byte) >= 0x7f:
out.write('\\x')
out.write(hexdigits[(ord(byte) & 0xf0) >> 4])
out.write(hexdigits[ord(byte) & 0xf])
else:
out.write(byte)
out.write(quote)
class PyTupleObjectPtr(PyObjectPtr):
_typename = 'PyTupleObject'
def __getitem__(self, i):
# Get the gdb.Value for the (PyObject*) with the given index:
field_ob_item = self.field('ob_item')
return field_ob_item[i]
def proxyval(self, visited):
# Guard against infinite loops:
if self.as_address() in visited:
return ProxyAlreadyVisited('(...)')
visited.add(self.as_address())
result = tuple(PyObjectPtr.from_pyobject_ptr(self[i]).proxyval(visited)
for i in safe_range(int_from_int(self.field('ob_size'))))
return result
def write_repr(self, out, visited):
# Guard against infinite loops:
if self.as_address() in visited:
out.write('(...)')
return
visited.add(self.as_address())
out.write('(')
for i in safe_range(int_from_int(self.field('ob_size'))):
if i > 0:
out.write(', ')
element = PyObjectPtr.from_pyobject_ptr(self[i])
element.write_repr(out, visited)
if self.field('ob_size') == 1:
out.write(',)')
else:
out.write(')')
class PyTypeObjectPtr(PyObjectPtr):
_typename = 'PyTypeObject'
def _unichr_is_printable(char):
# Logic adapted from Python 3's Tools/unicode/makeunicodedata.py
if char == u" ":
return True
import unicodedata
return unicodedata.category(char) not in ("C", "Z")
if sys.maxunicode >= 0x10000:
_unichr = unichr
else:
# Needed for proper surrogate support if sizeof(Py_UNICODE) is 2 in gdb
def _unichr(x):
if x < 0x10000:
return unichr(x)
x -= 0x10000
ch1 = 0xD800 | (x >> 10)
ch2 = 0xDC00 | (x & 0x3FF)
return unichr(ch1) + unichr(ch2)
class PyUnicodeObjectPtr(PyObjectPtr):
_typename = 'PyUnicodeObject'
def char_width(self):
_type_Py_UNICODE = gdb.lookup_type('Py_UNICODE')
return _type_Py_UNICODE.sizeof
def proxyval(self, visited):
global _is_pep393
if _is_pep393 is None:
fields = gdb.lookup_type('PyUnicodeObject').fields()
_is_pep393 = 'data' in [f.name for f in fields]
if _is_pep393:
# Python 3.3 and newer
may_have_surrogates = False
compact = self.field('_base')
ascii = compact['_base']
state = ascii['state']
is_compact_ascii = (int(state['ascii']) and int(state['compact']))
if not int(state['ready']):
# string is not ready
field_length = long(compact['wstr_length'])
may_have_surrogates = True
field_str = ascii['wstr']
else:
field_length = long(ascii['length'])
if is_compact_ascii:
field_str = ascii.address + 1
elif int(state['compact']):
field_str = compact.address + 1
else:
field_str = self.field('data')['any']
repr_kind = int(state['kind'])
if repr_kind == 1:
field_str = field_str.cast(_type_unsigned_char_ptr())
elif repr_kind == 2:
field_str = field_str.cast(_type_unsigned_short_ptr())
elif repr_kind == 4:
field_str = field_str.cast(_type_unsigned_int_ptr())
else:
# Python 3.2 and earlier
field_length = long(self.field('length'))
field_str = self.field('str')
may_have_surrogates = self.char_width() == 2
# Gather a list of ints from the Py_UNICODE array; these are either
# UCS-1, UCS-2 or UCS-4 code points:
if not may_have_surrogates:
Py_UNICODEs = [int(field_str[i]) for i in safe_range(field_length)]
else:
# A more elaborate routine if sizeof(Py_UNICODE) is 2 in the
# inferior process: we must join surrogate pairs.
Py_UNICODEs = []
i = 0
limit = safety_limit(field_length)
while i < limit:
ucs = int(field_str[i])
i += 1
if ucs < 0xD800 or ucs >= 0xDC00 or i == field_length:
Py_UNICODEs.append(ucs)
continue
# This could be a surrogate pair.
ucs2 = int(field_str[i])
if ucs2 < 0xDC00 or ucs2 > 0xDFFF:
continue
code = (ucs & 0x03FF) << 10
code |= ucs2 & 0x03FF
code += 0x00010000
Py_UNICODEs.append(code)
i += 1
# Convert the int code points to unicode characters, and generate a
# local unicode instance.
# This splits surrogate pairs if sizeof(Py_UNICODE) is 2 here (in gdb).
result = u''.join([
(_unichr(ucs) if ucs <= 0x10ffff else '\ufffd')
for ucs in Py_UNICODEs])
return result
def write_repr(self, out, visited):
# Write this out as a Python 3 str literal, i.e. without a "u" prefix
# Get a PyUnicodeObject* within the Python 2 gdb process:
proxy = self.proxyval(visited)
# Transliteration of Python 3's Object/unicodeobject.c:unicode_repr
# to Python 2:
if "'" in proxy and '"' not in proxy:
quote = '"'
else:
quote = "'"
out.write(quote)
i = 0
while i < len(proxy):
ch = proxy[i]
i += 1
# Escape quotes and backslashes
if ch == quote or ch == '\\':
out.write('\\')
out.write(ch)
# Map special whitespace to '\t', \n', '\r'
elif ch == '\t':
out.write('\\t')
elif ch == '\n':
out.write('\\n')
elif ch == '\r':
out.write('\\r')
# Map non-printable US ASCII to '\xhh' */
elif ch < ' ' or ch == 0x7F:
out.write('\\x')
out.write(hexdigits[(ord(ch) >> 4) & 0x000F])
out.write(hexdigits[ord(ch) & 0x000F])
# Copy ASCII characters as-is
elif ord(ch) < 0x7F:
out.write(ch)
# Non-ASCII characters
else:
ucs = ch
ch2 = None
if sys.maxunicode < 0x10000:
# If sizeof(Py_UNICODE) is 2 here (in gdb), join
# surrogate pairs before calling _unichr_is_printable.
if (i < len(proxy)
and 0xD800 <= ord(ch) < 0xDC00
and 0xDC00 <= ord(proxy[i]) <= 0xDFFF):
ch2 = proxy[i]
ucs = ch + ch2
i += 1
# Unfortuately, Python 2's unicode type doesn't seem
# to expose the "isprintable" method
printable = _unichr_is_printable(ucs)
if printable:
try:
ucs.encode(ENCODING)
except UnicodeEncodeError:
printable = False
# Map Unicode whitespace and control characters
# (categories Z* and C* except ASCII space)
if not printable:
if ch2 is not None:
# Match Python 3's representation of non-printable
# wide characters.
code = (ord(ch) & 0x03FF) << 10
code |= ord(ch2) & 0x03FF
code += 0x00010000
else:
code = ord(ucs)
# Map 8-bit characters to '\\xhh'
if code <= 0xff:
out.write('\\x')
out.write(hexdigits[(code >> 4) & 0x000F])
out.write(hexdigits[code & 0x000F])
# Map 21-bit characters to '\U00xxxxxx'
elif code >= 0x10000:
out.write('\\U')
out.write(hexdigits[(code >> 28) & 0x0000000F])
out.write(hexdigits[(code >> 24) & 0x0000000F])
out.write(hexdigits[(code >> 20) & 0x0000000F])
out.write(hexdigits[(code >> 16) & 0x0000000F])
out.write(hexdigits[(code >> 12) & 0x0000000F])
out.write(hexdigits[(code >> 8) & 0x0000000F])
out.write(hexdigits[(code >> 4) & 0x0000000F])
out.write(hexdigits[code & 0x0000000F])
# Map 16-bit characters to '\uxxxx'
else:
out.write('\\u')
out.write(hexdigits[(code >> 12) & 0x000F])
out.write(hexdigits[(code >> 8) & 0x000F])
out.write(hexdigits[(code >> 4) & 0x000F])
out.write(hexdigits[code & 0x000F])
else:
# Copy characters as-is
out.write(ch)
if ch2 is not None:
out.write(ch2)
out.write(quote)
class wrapperobject(PyObjectPtr):
_typename = 'wrapperobject'
def safe_name(self):
try:
name = self.field('descr')['d_base']['name'].string()
return repr(name)
except (NullPyObjectPtr, RuntimeError, UnicodeDecodeError):
return '<unknown name>'
def safe_tp_name(self):
try:
return self.field('self')['ob_type']['tp_name'].string()
except (NullPyObjectPtr, RuntimeError, UnicodeDecodeError):
return '<unknown tp_name>'
def safe_self_addresss(self):
try:
address = long(self.field('self'))
return '%#x' % address
except (NullPyObjectPtr, RuntimeError):
return '<failed to get self address>'
def proxyval(self, visited):
name = self.safe_name()
tp_name = self.safe_tp_name()
self_address = self.safe_self_addresss()
return ("<method-wrapper %s of %s object at %s>"
% (name, tp_name, self_address))
def write_repr(self, out, visited):
proxy = self.proxyval(visited)
out.write(proxy)
def int_from_int(gdbval):
return int(gdbval)
def stringify(val):
# TODO: repr() puts everything on one line; pformat can be nicer, but
# can lead to v.long results; this function isolates the choice
if True:
return repr(val)
else:
from pprint import pformat
return pformat(val)
class PyObjectPtrPrinter:
"Prints a (PyObject*)"
def __init__ (self, gdbval):
self.gdbval = gdbval
def to_string (self):
pyop = PyObjectPtr.from_pyobject_ptr(self.gdbval)
if True:
return pyop.get_truncated_repr(MAX_OUTPUT_LEN)
else:
# Generate full proxy value then stringify it.
# Doing so could be expensive
proxyval = pyop.proxyval(set())
return stringify(proxyval)
def pretty_printer_lookup(gdbval):
type = gdbval.type.unqualified()
if type.code != gdb.TYPE_CODE_PTR:
return None
type = type.target().unqualified()
t = str(type)
if t in ("PyObject", "PyFrameObject", "PyUnicodeObject", "wrapperobject"):
return PyObjectPtrPrinter(gdbval)
"""
During development, I've been manually invoking the code in this way:
(gdb) python
import sys
sys.path.append('/home/david/coding/python-gdb')
import libpython
end
then reloading it after each edit like this:
(gdb) python reload(libpython)
The following code should ensure that the prettyprinter is registered
if the code is autoloaded by gdb when visiting libpython.so, provided
that this python file is installed to the same path as the library (or its
.debug file) plus a "-gdb.py" suffix, e.g:
/usr/lib/libpython2.6.so.1.0-gdb.py
/usr/lib/debug/usr/lib/libpython2.6.so.1.0.debug-gdb.py
"""
def register (obj):
if obj is None:
obj = gdb
# Wire up the pretty-printer
obj.pretty_printers.append(pretty_printer_lookup)
register (gdb.current_objfile ())
# Unfortunately, the exact API exposed by the gdb module varies somewhat
# from build to build
# See http://bugs.python.org/issue8279?#msg102276
class Frame(object):
'''
Wrapper for gdb.Frame, adding various methods
'''
def __init__(self, gdbframe):
self._gdbframe = gdbframe
def older(self):
older = self._gdbframe.older()
if older:
return Frame(older)
else:
return None
def newer(self):
newer = self._gdbframe.newer()
if newer:
return Frame(newer)
else:
return None
def select(self):
'''If supported, select this frame and return True; return False if unsupported
Not all builds have a gdb.Frame.select method; seems to be present on Fedora 12
onwards, but absent on Ubuntu buildbot'''
if not hasattr(self._gdbframe, 'select'):
print ('Unable to select frame: '
'this build of gdb does not expose a gdb.Frame.select method')
return False
self._gdbframe.select()
return True
def get_index(self):
'''Calculate index of frame, starting at 0 for the newest frame within
this thread'''
index = 0
# Go down until you reach the newest frame:
iter_frame = self
while iter_frame.newer():
index += 1
iter_frame = iter_frame.newer()
return index
# We divide frames into:
# - "python frames":
# - "bytecode frames" i.e. PyEval_EvalFrameEx
# - "other python frames": things that are of interest from a python
# POV, but aren't bytecode (e.g. GC, GIL)
# - everything else
def is_python_frame(self):
'''Is this a _PyEval_EvalFrameDefault frame, or some other important
frame? (see is_other_python_frame for what "important" means in this
context)'''
if self.is_evalframe():
return True
if self.is_other_python_frame():
return True
return False
def is_evalframe(self):
'''Is this a _PyEval_EvalFrameDefault frame?'''
if self._gdbframe.name() == EVALFRAME:
'''
I believe we also need to filter on the inline
struct frame_id.inline_depth, only regarding frames with
an inline depth of 0 as actually being this function
So we reject those with type gdb.INLINE_FRAME
'''
if self._gdbframe.type() == gdb.NORMAL_FRAME:
# We have a _PyEval_EvalFrameDefault frame:
return True
return False
def is_other_python_frame(self):
'''Is this frame worth displaying in python backtraces?
Examples:
- waiting on the GIL
- garbage-collecting
- within a CFunction
If it is, return a descriptive string
For other frames, return False
'''
if self.is_waiting_for_gil():
return 'Waiting for the GIL'
if self.is_gc_collect():
return 'Garbage-collecting'
# Detect invocations of PyCFunction instances:
frame = self._gdbframe
caller = frame.name()
if not caller:
return False
if (caller.startswith('cfunction_vectorcall_') or
caller == 'cfunction_call'):
arg_name = 'func'
# Within that frame:
# "func" is the local containing the PyObject* of the
# PyCFunctionObject instance
# "f" is the same value, but cast to (PyCFunctionObject*)
# "self" is the (PyObject*) of the 'self'
try:
# Use the prettyprinter for the func:
func = frame.read_var(arg_name)
return str(func)
except ValueError:
return ('PyCFunction invocation (unable to read %s: '
'missing debuginfos?)' % arg_name)
except RuntimeError:
return 'PyCFunction invocation (unable to read %s)' % arg_name
if caller == 'wrapper_call':
arg_name = 'wp'
try:
func = frame.read_var(arg_name)
return str(func)
except ValueError:
return ('<wrapper_call invocation (unable to read %s: '
'missing debuginfos?)>' % arg_name)
except RuntimeError:
return '<wrapper_call invocation (unable to read %s)>' % arg_name
# This frame isn't worth reporting:
return False
def is_waiting_for_gil(self):
'''Is this frame waiting on the GIL?'''
# This assumes the _POSIX_THREADS version of Python/ceval_gil.h:
name = self._gdbframe.name()
if name:
return (name == 'take_gil')
def is_gc_collect(self):
'''Is this frame "collect" within the garbage-collector?'''
return self._gdbframe.name() == 'collect'
def get_pyop(self):
try:
f = self._gdbframe.read_var('f')
frame = PyFrameObjectPtr.from_pyobject_ptr(f)
if not frame.is_optimized_out():
return frame
# gdb is unable to get the "f" argument of PyEval_EvalFrameEx()
# because it was "optimized out". Try to get "f" from the frame
# of the caller, PyEval_EvalCodeEx().
orig_frame = frame
caller = self._gdbframe.older()
if caller:
f = caller.read_var('f')
frame = PyFrameObjectPtr.from_pyobject_ptr(f)
if not frame.is_optimized_out():
return frame
return orig_frame
except ValueError:
return None
@classmethod
def get_selected_frame(cls):
_gdbframe = gdb.selected_frame()
if _gdbframe:
return Frame(_gdbframe)
return None
@classmethod
def get_selected_python_frame(cls):
'''Try to obtain the Frame for the python-related code in the selected
frame, or None'''
try:
frame = cls.get_selected_frame()
except gdb.error:
# No frame: Python didn't start yet
return None
while frame:
if frame.is_python_frame():
return frame
frame = frame.older()
# Not found:
return None
@classmethod
def get_selected_bytecode_frame(cls):
'''Try to obtain the Frame for the python bytecode interpreter in the
selected GDB frame, or None'''
frame = cls.get_selected_frame()
while frame:
if frame.is_evalframe():
return frame
frame = frame.older()
# Not found:
return None
def print_summary(self):
if self.is_evalframe():
pyop = self.get_pyop()
if pyop:
line = pyop.get_truncated_repr(MAX_OUTPUT_LEN)
write_unicode(sys.stdout, '#%i %s\n' % (self.get_index(), line))
if not pyop.is_optimized_out():
line = pyop.current_line()
if line is not None:
sys.stdout.write(' %s\n' % line.strip())
else:
sys.stdout.write('#%i (unable to read python frame information)\n' % self.get_index())
else:
info = self.is_other_python_frame()
if info:
sys.stdout.write('#%i %s\n' % (self.get_index(), info))
else:
sys.stdout.write('#%i\n' % self.get_index())
def print_traceback(self):
if self.is_evalframe():
pyop = self.get_pyop()
if pyop:
pyop.print_traceback()
if not pyop.is_optimized_out():
line = pyop.current_line()
if line is not None:
sys.stdout.write(' %s\n' % line.strip())
else:
sys.stdout.write(' (unable to read python frame information)\n')
else:
info = self.is_other_python_frame()
if info:
sys.stdout.write(' %s\n' % info)
else:
sys.stdout.write(' (not a python frame)\n')
class PyList(gdb.Command):
'''List the current Python source code, if any
Use
py-list START
to list at a different line number within the python source.
Use
py-list START, END
to list a specific range of lines within the python source.
'''
def __init__(self):
gdb.Command.__init__ (self,
"py-list",
gdb.COMMAND_FILES,
gdb.COMPLETE_NONE)
def invoke(self, args, from_tty):
import re
start = None
end = None
m = re.match(r'\s*(\d+)\s*', args)
if m:
start = int(m.group(0))
end = start + 10
m = re.match(r'\s*(\d+)\s*,\s*(\d+)\s*', args)
if m:
start, end = map(int, m.groups())
# py-list requires an actual PyEval_EvalFrameEx frame:
frame = Frame.get_selected_bytecode_frame()
if not frame:
print('Unable to locate gdb frame for python bytecode interpreter')
return
pyop = frame.get_pyop()
if not pyop or pyop.is_optimized_out():
print(UNABLE_READ_INFO_PYTHON_FRAME)
return
filename = pyop.filename()
lineno = pyop.current_line_num()
if lineno is None:
print('Unable to read python frame line number')
return
if start is None:
start = lineno - 5
end = lineno + 5
if start<1:
start = 1
try:
f = open(os_fsencode(filename), 'r')
except IOError as err:
sys.stdout.write('Unable to open %s: %s\n'
% (filename, err))
return
with f:
all_lines = f.readlines()
# start and end are 1-based, all_lines is 0-based;
# so [start-1:end] as a python slice gives us [start, end] as a
# closed interval
for i, line in enumerate(all_lines[start-1:end]):
linestr = str(i+start)
# Highlight current line:
if i + start == lineno:
linestr = '>' + linestr
sys.stdout.write('%4s %s' % (linestr, line))
# ...and register the command:
PyList()
def move_in_stack(move_up):
'''Move up or down the stack (for the py-up/py-down command)'''
frame = Frame.get_selected_python_frame()
if not frame:
print('Unable to locate python frame')
return
while frame:
if move_up:
iter_frame = frame.older()
else:
iter_frame = frame.newer()
if not iter_frame:
break
if iter_frame.is_python_frame():
# Result:
if iter_frame.select():
iter_frame.print_summary()
return
frame = iter_frame
if move_up:
print('Unable to find an older python frame')
else:
print('Unable to find a newer python frame')
class PyUp(gdb.Command):
'Select and print the python stack frame that called this one (if any)'
def __init__(self):
gdb.Command.__init__ (self,
"py-up",
gdb.COMMAND_STACK,
gdb.COMPLETE_NONE)
def invoke(self, args, from_tty):
move_in_stack(move_up=True)
class PyDown(gdb.Command):
'Select and print the python stack frame called by this one (if any)'
def __init__(self):
gdb.Command.__init__ (self,
"py-down",
gdb.COMMAND_STACK,
gdb.COMPLETE_NONE)
def invoke(self, args, from_tty):
move_in_stack(move_up=False)
# Not all builds of gdb have gdb.Frame.select
if hasattr(gdb.Frame, 'select'):
PyUp()
PyDown()
class PyBacktraceFull(gdb.Command):
'Display the current python frame and all the frames within its call stack (if any)'
def __init__(self):
gdb.Command.__init__ (self,
"py-bt-full",
gdb.COMMAND_STACK,
gdb.COMPLETE_NONE)
def invoke(self, args, from_tty):
frame = Frame.get_selected_python_frame()
if not frame:
print('Unable to locate python frame')
return
while frame:
if frame.is_python_frame():
frame.print_summary()
frame = frame.older()
PyBacktraceFull()
class PyBacktrace(gdb.Command):
'Display the current python frame and all the frames within its call stack (if any)'
def __init__(self):
gdb.Command.__init__ (self,
"py-bt",
gdb.COMMAND_STACK,
gdb.COMPLETE_NONE)
def invoke(self, args, from_tty):
frame = Frame.get_selected_python_frame()
if not frame:
print('Unable to locate python frame')
return
sys.stdout.write('Traceback (most recent call first):\n')
while frame:
if frame.is_python_frame():
frame.print_traceback()
frame = frame.older()
PyBacktrace()
class PyPrint(gdb.Command):
'Look up the given python variable name, and print it'
def __init__(self):
gdb.Command.__init__ (self,
"py-print",
gdb.COMMAND_DATA,
gdb.COMPLETE_NONE)
def invoke(self, args, from_tty):
name = str(args)
frame = Frame.get_selected_python_frame()
if not frame:
print('Unable to locate python frame')
return
pyop_frame = frame.get_pyop()
if not pyop_frame:
print(UNABLE_READ_INFO_PYTHON_FRAME)
return
pyop_var, scope = pyop_frame.get_var_by_name(name)
if pyop_var:
print('%s %r = %s'
% (scope,
name,
pyop_var.get_truncated_repr(MAX_OUTPUT_LEN)))
else:
print('%r not found' % name)
PyPrint()
class PyLocals(gdb.Command):
'Look up the given python variable name, and print it'
def __init__(self):
gdb.Command.__init__ (self,
"py-locals",
gdb.COMMAND_DATA,
gdb.COMPLETE_NONE)
def invoke(self, args, from_tty):
name = str(args)
frame = Frame.get_selected_python_frame()
if not frame:
print('Unable to locate python frame')
return
pyop_frame = frame.get_pyop()
if not pyop_frame:
print(UNABLE_READ_INFO_PYTHON_FRAME)
return
for pyop_name, pyop_value in pyop_frame.iter_locals():
print('%s = %s' % (
pyop_name.proxyval(set()),
pyop_value.get_truncated_repr(MAX_OUTPUT_LEN),
))
PyLocals()
##################################################################
## added, not in CPython
##################################################################
import re
import warnings
import tempfile
import functools
import textwrap
import itertools
import traceback
def dont_suppress_errors(function):
"*sigh*, readline"
@functools.wraps(function)
def wrapper(*args, **kwargs):
try:
return function(*args, **kwargs)
except Exception:
traceback.print_exc()
raise
return wrapper
class PyGlobals(gdb.Command):
'List all the globals in the currently select Python frame'
def __init__(self):
gdb.Command.__init__ (self,
"py-globals",
gdb.COMMAND_DATA,
gdb.COMPLETE_NONE)
@dont_suppress_errors
def invoke(self, args, from_tty):
name = str(args)
frame = Frame.get_selected_python_frame()
if not frame:
print('Unable to locate python frame')
return
pyop_frame = frame.get_pyop()
if not pyop_frame:
print(UNABLE_READ_INFO_PYTHON_FRAME)
return
for pyop_name, pyop_value in pyop_frame.iter_locals():
print('%s = %s'
% (pyop_name.proxyval(set()),
pyop_value.get_truncated_repr(MAX_OUTPUT_LEN)))
def get_namespace(self, pyop_frame):
return pyop_frame.iter_globals()
PyGlobals()
# This function used to be a part of CPython's libpython.py (as a member function of frame).
# It isn't anymore, so I copied it.
def is_evalframeex(frame):
'''Is this a PyEval_EvalFrameEx frame?'''
if frame._gdbframe.name() == 'PyEval_EvalFrameEx':
'''
I believe we also need to filter on the inline
struct frame_id.inline_depth, only regarding frames with
an inline depth of 0 as actually being this function
So we reject those with type gdb.INLINE_FRAME
'''
if frame._gdbframe.type() == gdb.NORMAL_FRAME:
# We have a PyEval_EvalFrameEx frame:
return True
return False
class PyNameEquals(gdb.Function):
def _get_pycurframe_attr(self, attr):
frame = Frame(gdb.selected_frame())
if is_evalframeex(frame):
pyframe = frame.get_pyop()
if pyframe is None:
warnings.warn("Use a Python debug build, Python breakpoints "
"won't work otherwise.")
return None
return getattr(pyframe, attr).proxyval(set())
return None
@dont_suppress_errors
def invoke(self, funcname):
attr = self._get_pycurframe_attr('co_name')
return attr is not None and attr == funcname.string()
PyNameEquals("pyname_equals")
class PyModEquals(PyNameEquals):
@dont_suppress_errors
def invoke(self, modname):
attr = self._get_pycurframe_attr('co_filename')
if attr is not None:
filename, ext = os.path.splitext(os.path.basename(attr))
return filename == modname.string()
return False
PyModEquals("pymod_equals")
class PyBreak(gdb.Command):
"""
Set a Python breakpoint. Examples:
Break on any function or method named 'func' in module 'modname'
py-break modname.func
Break on any function or method named 'func'
py-break func
"""
@dont_suppress_errors
def invoke(self, funcname, from_tty):
if '.' in funcname:
modname, dot, funcname = funcname.rpartition('.')
cond = '$pyname_equals("%s") && $pymod_equals("%s")' % (funcname,
modname)
else:
cond = '$pyname_equals("%s")' % funcname
gdb.execute('break PyEval_EvalFrameEx if ' + cond)
PyBreak("py-break", gdb.COMMAND_RUNNING, gdb.COMPLETE_NONE)
class _LoggingState(object):
"""
State that helps to provide a reentrant gdb.execute() function.
"""
def __init__(self):
f = tempfile.NamedTemporaryFile('r+')
self.file = f
self.filename = f.name
self.fd = f.fileno()
_execute("set logging file %s" % self.filename)
self.file_position_stack = []
def __enter__(self):
if not self.file_position_stack:
_execute("set logging redirect on")
_execute("set logging on")
_execute("set pagination off")
self.file_position_stack.append(os.fstat(self.fd).st_size)
return self
def getoutput(self):
gdb.flush()
self.file.seek(self.file_position_stack[-1])
result = self.file.read()
return result
def __exit__(self, exc_type, exc_val, tb):
startpos = self.file_position_stack.pop()
self.file.seek(startpos)
self.file.truncate()
if not self.file_position_stack:
_execute("set logging off")
_execute("set logging redirect off")
_execute("set pagination on")
def execute(command, from_tty=False, to_string=False):
"""
Replace gdb.execute() with this function and have it accept a 'to_string'
argument (new in 7.2). Have it properly capture stderr also. Ensure
reentrancy.
"""
if to_string:
with _logging_state as state:
_execute(command, from_tty)
return state.getoutput()
else:
_execute(command, from_tty)
_execute = gdb.execute
gdb.execute = execute
_logging_state = _LoggingState()
def get_selected_inferior():
"""
Return the selected inferior in gdb.
"""
# Woooh, another bug in gdb! Is there an end in sight?
# http://sourceware.org/bugzilla/show_bug.cgi?id=12212
return gdb.inferiors()[0]
selected_thread = gdb.selected_thread()
for inferior in gdb.inferiors():
for thread in inferior.threads():
if thread == selected_thread:
return inferior
def source_gdb_script(script_contents, to_string=False):
"""
Source a gdb script with script_contents passed as a string. This is useful
to provide defines for py-step and py-next to make them repeatable (this is
not possible with gdb.execute()). See
http://sourceware.org/bugzilla/show_bug.cgi?id=12216
"""
fd, filename = tempfile.mkstemp()
f = os.fdopen(fd, 'w')
f.write(script_contents)
f.close()
gdb.execute("source %s" % filename, to_string=to_string)
os.remove(filename)
def register_defines():
source_gdb_script(textwrap.dedent("""\
define py-step
-py-step
end
define py-next
-py-next
end
document py-step
%s
end
document py-next
%s
end
""") % (PyStep.__doc__, PyNext.__doc__))
def stackdepth(frame):
"Tells the stackdepth of a gdb frame."
depth = 0
while frame:
frame = frame.older()
depth += 1
return depth
class ExecutionControlCommandBase(gdb.Command):
"""
Superclass for language specific execution control. Language specific
features should be implemented by lang_info using the LanguageInfo
interface. 'name' is the name of the command.
"""
def __init__(self, name, lang_info):
super(ExecutionControlCommandBase, self).__init__(
name, gdb.COMMAND_RUNNING, gdb.COMPLETE_NONE)
self.lang_info = lang_info
def install_breakpoints(self):
all_locations = itertools.chain(
self.lang_info.static_break_functions(),
self.lang_info.runtime_break_functions())
for location in all_locations:
result = gdb.execute('break %s' % location, to_string=True)
yield re.search(r'Breakpoint (\d+)', result).group(1)
def delete_breakpoints(self, breakpoint_list):
for bp in breakpoint_list:
gdb.execute("delete %s" % bp)
def filter_output(self, result):
reflags = re.MULTILINE
output_on_halt = [
(r'^Program received signal .*', reflags|re.DOTALL),
(r'.*[Ww]arning.*', 0),
(r'^Program exited .*', reflags),
]
output_always = [
# output when halting on a watchpoint
(r'^(Old|New) value = .*', reflags),
# output from the 'display' command
(r'^\d+: \w+ = .*', reflags),
]
def filter_output(regexes):
output = []
for regex, flags in regexes:
for match in re.finditer(regex, result, flags):
output.append(match.group(0))
return '\n'.join(output)
# Filter the return value output of the 'finish' command
match_finish = re.search(r'^Value returned is \$\d+ = (.*)', result,
re.MULTILINE)
if match_finish:
finish_output = 'Value returned: %s\n' % match_finish.group(1)
else:
finish_output = ''
return (filter_output(output_on_halt),
finish_output + filter_output(output_always))
def stopped(self):
return get_selected_inferior().pid == 0
def finish_executing(self, result):
"""
After doing some kind of code running in the inferior, print the line
of source code or the result of the last executed gdb command (passed
in as the `result` argument).
"""
output_on_halt, output_always = self.filter_output(result)
if self.stopped():
print(output_always)
print(output_on_halt)
else:
frame = gdb.selected_frame()
source_line = self.lang_info.get_source_line(frame)
if self.lang_info.is_relevant_function(frame):
raised_exception = self.lang_info.exc_info(frame)
if raised_exception:
print(raised_exception)
if source_line:
if output_always.rstrip():
print(output_always.rstrip())
print(source_line)
else:
print(result)
def _finish(self):
"""
Execute until the function returns (or until something else makes it
stop)
"""
if gdb.selected_frame().older() is not None:
return gdb.execute('finish', to_string=True)
else:
# outermost frame, continue
return gdb.execute('cont', to_string=True)
def _finish_frame(self):
"""
Execute until the function returns to a relevant caller.
"""
while True:
result = self._finish()
try:
frame = gdb.selected_frame()
except RuntimeError:
break
hitbp = re.search(r'Breakpoint (\d+)', result)
is_relevant = self.lang_info.is_relevant_function(frame)
if hitbp or is_relevant or self.stopped():
break
return result
def finish(self, *args):
"Implements the finish command."
result = self._finish_frame()
self.finish_executing(result)
def step(self, stepinto, stepover_command='next'):
"""
Do a single step or step-over. Returns the result of the last gdb
command that made execution stop.
This implementation, for stepping, sets (conditional) breakpoints for
all functions that are deemed relevant. It then does a step over until
either something halts execution, or until the next line is reached.
If, however, stepover_command is given, it should be a string gdb
command that continues execution in some way. The idea is that the
caller has set a (conditional) breakpoint or watchpoint that can work
more efficiently than the step-over loop. For Python this means setting
a watchpoint for f->f_lasti, which means we can then subsequently
"finish" frames.
We want f->f_lasti instead of f->f_lineno, because the latter only
works properly with local trace functions, see
PyFrameObjectPtr.current_line_num and PyFrameObjectPtr.addr2line.
"""
if stepinto:
breakpoint_list = list(self.install_breakpoints())
beginframe = gdb.selected_frame()
if self.lang_info.is_relevant_function(beginframe):
# If we start in a relevant frame, initialize stuff properly. If
# we don't start in a relevant frame, the loop will halt
# immediately. So don't call self.lang_info.lineno() as it may
# raise for irrelevant frames.
beginline = self.lang_info.lineno(beginframe)
if not stepinto:
depth = stackdepth(beginframe)
newframe = beginframe
while True:
if self.lang_info.is_relevant_function(newframe):
result = gdb.execute(stepover_command, to_string=True)
else:
result = self._finish_frame()
if self.stopped():
break
newframe = gdb.selected_frame()
is_relevant_function = self.lang_info.is_relevant_function(newframe)
try:
framename = newframe.name()
except RuntimeError:
framename = None
m = re.search(r'Breakpoint (\d+)', result)
if m:
if is_relevant_function and m.group(1) in breakpoint_list:
# although we hit a breakpoint, we still need to check
# that the function, in case hit by a runtime breakpoint,
# is in the right context
break
if newframe != beginframe:
# new function
if not stepinto:
# see if we returned to the caller
newdepth = stackdepth(newframe)
is_relevant_function = (newdepth < depth and
is_relevant_function)
if is_relevant_function:
break
else:
# newframe equals beginframe, check for a difference in the
# line number
lineno = self.lang_info.lineno(newframe)
if lineno and lineno != beginline:
break
if stepinto:
self.delete_breakpoints(breakpoint_list)
self.finish_executing(result)
def run(self, args, from_tty):
self.finish_executing(gdb.execute('run ' + args, to_string=True))
def cont(self, *args):
self.finish_executing(gdb.execute('cont', to_string=True))
class LanguageInfo(object):
"""
This class defines the interface that ExecutionControlCommandBase needs to
provide language-specific execution control.
Classes that implement this interface should implement:
lineno(frame)
Tells the current line number (only called for a relevant frame).
If lineno is a false value it is not checked for a difference.
is_relevant_function(frame)
tells whether we care about frame 'frame'
get_source_line(frame)
get the line of source code for the current line (only called for a
relevant frame). If the source code cannot be retrieved this
function should return None
exc_info(frame) -- optional
tells whether an exception was raised, if so, it should return a
string representation of the exception value, None otherwise.
static_break_functions()
returns an iterable of function names that are considered relevant
and should halt step-into execution. This is needed to provide a
performing step-into
runtime_break_functions() -- optional
list of functions that we should break into depending on the
context
"""
def exc_info(self, frame):
"See this class' docstring."
def runtime_break_functions(self):
"""
Implement this if the list of step-into functions depends on the
context.
"""
return ()
class PythonInfo(LanguageInfo):
def pyframe(self, frame):
pyframe = Frame(frame).get_pyop()
if pyframe:
return pyframe
else:
raise gdb.RuntimeError(
"Unable to find the Python frame, run your code with a debug "
"build (configure with --with-pydebug or compile with -g).")
def lineno(self, frame):
return self.pyframe(frame).current_line_num()
def is_relevant_function(self, frame):
return Frame(frame).is_evalframeex()
def get_source_line(self, frame):
try:
pyframe = self.pyframe(frame)
return '%4d %s' % (pyframe.current_line_num(),
pyframe.current_line().rstrip())
except IOError:
return None
def exc_info(self, frame):
try:
tstate = frame.read_var('tstate').dereference()
if gdb.parse_and_eval('tstate->frame == f'):
# tstate local variable initialized, check for an exception
if sys.version_info >= (3, 12, 0, 'alpha', 6):
inf_type = inf_value = tstate['current_exception']
else:
inf_type = tstate['curexc_type']
inf_value = tstate['curexc_value']
if inf_type:
return 'An exception was raised: %s' % (inf_value,)
except (ValueError, RuntimeError):
# Could not read the variable tstate or it's memory, it's ok
pass
def static_break_functions(self):
yield 'PyEval_EvalFrameEx'
class PythonStepperMixin(object):
"""
Make this a mixin so CyStep can also inherit from this and use a
CythonCodeStepper at the same time.
"""
def python_step(self, stepinto):
"""
Set a watchpoint on the Python bytecode instruction pointer and try
to finish the frame
"""
output = gdb.execute('watch f->f_lasti', to_string=True)
watchpoint = int(re.search(r'[Ww]atchpoint (\d+):', output).group(1))
self.step(stepinto=stepinto, stepover_command='finish')
gdb.execute('delete %s' % watchpoint)
class PyStep(ExecutionControlCommandBase, PythonStepperMixin):
"Step through Python code."
stepinto = True
@dont_suppress_errors
def invoke(self, args, from_tty):
self.python_step(stepinto=self.stepinto)
class PyNext(PyStep):
"Step-over Python code."
stepinto = False
class PyFinish(ExecutionControlCommandBase):
"Execute until function returns to a caller."
invoke = dont_suppress_errors(ExecutionControlCommandBase.finish)
class PyRun(ExecutionControlCommandBase):
"Run the program."
invoke = dont_suppress_errors(ExecutionControlCommandBase.run)
class PyCont(ExecutionControlCommandBase):
invoke = dont_suppress_errors(ExecutionControlCommandBase.cont)
def _pointervalue(gdbval):
"""
Return the value of the pointer as a Python int.
gdbval.type must be a pointer type
"""
# don't convert with int() as it will raise a RuntimeError
if gdbval.address is not None:
return int(gdbval.address)
else:
# the address attribute is None sometimes, in which case we can
# still convert the pointer to an int
return int(gdbval)
def pointervalue(gdbval):
pointer = _pointervalue(gdbval)
try:
if pointer < 0:
raise gdb.GdbError("Negative pointer value, presumably a bug "
"in gdb, aborting.")
except RuntimeError:
# work around yet another bug in gdb where you get random behaviour
# and tracebacks
pass
return pointer
def get_inferior_unicode_postfix():
try:
gdb.parse_and_eval('PyUnicode_FromEncodedObject')
except RuntimeError:
try:
gdb.parse_and_eval('PyUnicodeUCS2_FromEncodedObject')
except RuntimeError:
return 'UCS4'
else:
return 'UCS2'
else:
return ''
class PythonCodeExecutor(object):
Py_single_input = 256
Py_file_input = 257
Py_eval_input = 258
def malloc(self, size):
chunk = (gdb.parse_and_eval("(void *) malloc((size_t) %d)" % size))
pointer = pointervalue(chunk)
if pointer == 0:
raise gdb.GdbError("No memory could be allocated in the inferior.")
return pointer
def alloc_string(self, string):
pointer = self.malloc(len(string))
get_selected_inferior().write_memory(pointer, string)
return pointer
def alloc_pystring(self, string):
stringp = self.alloc_string(string)
PyString_FromStringAndSize = 'PyString_FromStringAndSize'
try:
gdb.parse_and_eval(PyString_FromStringAndSize)
except RuntimeError:
# Python 3
PyString_FromStringAndSize = ('PyUnicode%s_FromStringAndSize' %
(get_inferior_unicode_postfix(),))
try:
result = gdb.parse_and_eval(
'(PyObject *) %s((char *) %d, (size_t) %d)' % (
PyString_FromStringAndSize, stringp, len(string)))
finally:
self.free(stringp)
pointer = pointervalue(result)
if pointer == 0:
raise gdb.GdbError("Unable to allocate Python string in "
"the inferior.")
return pointer
def free(self, pointer):
gdb.parse_and_eval("(void) free((void *) %d)" % pointer)
def incref(self, pointer):
"Increment the reference count of a Python object in the inferior."
gdb.parse_and_eval('Py_IncRef((PyObject *) %d)' % pointer)
def xdecref(self, pointer):
"Decrement the reference count of a Python object in the inferior."
# Py_DecRef is like Py_XDECREF, but a function. So we don't have
# to check for NULL. This should also decref all our allocated
# Python strings.
gdb.parse_and_eval('Py_DecRef((PyObject *) %d)' % pointer)
def evalcode(self, code, input_type, global_dict=None, local_dict=None):
"""
Evaluate python code `code` given as a string in the inferior and
return the result as a gdb.Value. Returns a new reference in the
inferior.
Of course, executing any code in the inferior may be dangerous and may
leave the debuggee in an unsafe state or terminate it altogether.
"""
if '\0' in code:
raise gdb.GdbError("String contains NUL byte.")
code += '\0'
pointer = self.alloc_string(code)
globalsp = pointervalue(global_dict)
localsp = pointervalue(local_dict)
if globalsp == 0 or localsp == 0:
raise gdb.GdbError("Unable to obtain or create locals or globals.")
code = """
PyRun_String(
(char *) %(code)d,
(int) %(start)d,
(PyObject *) %(globals)s,
(PyObject *) %(locals)d)
""" % dict(code=pointer, start=input_type,
globals=globalsp, locals=localsp)
with FetchAndRestoreError():
try:
pyobject_return_value = gdb.parse_and_eval(code)
finally:
self.free(pointer)
return pyobject_return_value
class FetchAndRestoreError(PythonCodeExecutor):
"""
Context manager that fetches the error indicator in the inferior and
restores it on exit.
"""
def __init__(self):
self.sizeof_PyObjectPtr = gdb.lookup_type('PyObject').pointer().sizeof
self.pointer = self.malloc(self.sizeof_PyObjectPtr * 3)
type = self.pointer
value = self.pointer + self.sizeof_PyObjectPtr
traceback = self.pointer + self.sizeof_PyObjectPtr * 2
self.errstate = type, value, traceback
def __enter__(self):
gdb.parse_and_eval("PyErr_Fetch(%d, %d, %d)" % self.errstate)
def __exit__(self, *args):
if gdb.parse_and_eval("(int) PyErr_Occurred()"):
gdb.parse_and_eval("PyErr_Print()")
pyerr_restore = ("PyErr_Restore("
"(PyObject *) *%d,"
"(PyObject *) *%d,"
"(PyObject *) *%d)")
try:
gdb.parse_and_eval(pyerr_restore % self.errstate)
finally:
self.free(self.pointer)
class FixGdbCommand(gdb.Command):
def __init__(self, command, actual_command):
super(FixGdbCommand, self).__init__(command, gdb.COMMAND_DATA,
gdb.COMPLETE_NONE)
self.actual_command = actual_command
def fix_gdb(self):
"""
It seems that invoking either 'cy exec' and 'py-exec' work perfectly
fine, but after this gdb's python API is entirely broken.
Maybe some uncleared exception value is still set?
sys.exc_clear() didn't help. A demonstration:
(gdb) cy exec 'hello'
'hello'
(gdb) python gdb.execute('cont')
RuntimeError: Cannot convert value to int.
Error while executing Python code.
(gdb) python gdb.execute('cont')
[15148 refs]
Program exited normally.
"""
warnings.filterwarnings('ignore', r'.*', RuntimeWarning,
re.escape(__name__))
try:
int(gdb.parse_and_eval("(void *) 0")) == 0
except RuntimeError:
pass
# warnings.resetwarnings()
@dont_suppress_errors
def invoke(self, args, from_tty):
self.fix_gdb()
try:
gdb.execute('%s %s' % (self.actual_command, args))
except RuntimeError as e:
raise gdb.GdbError(str(e))
self.fix_gdb()
def _evalcode_python(executor, code, input_type):
"""
Execute Python code in the most recent stack frame.
"""
global_dict = gdb.parse_and_eval('PyEval_GetGlobals()')
local_dict = gdb.parse_and_eval('PyEval_GetLocals()')
if (pointervalue(global_dict) == 0 or pointervalue(local_dict) == 0):
raise gdb.GdbError("Unable to find the locals or globals of the "
"most recent Python function (relative to the "
"selected frame).")
return executor.evalcode(code, input_type, global_dict, local_dict)
class PyExec(gdb.Command):
def readcode(self, expr):
if expr:
return expr, PythonCodeExecutor.Py_single_input
else:
lines = []
while True:
try:
if sys.version_info[0] == 2:
line = raw_input()
else:
line = input('>')
except EOFError:
break
else:
if line.rstrip() == 'end':
break
lines.append(line)
return '\n'.join(lines), PythonCodeExecutor.Py_file_input
@dont_suppress_errors
def invoke(self, expr, from_tty):
expr, input_type = self.readcode(expr)
executor = PythonCodeExecutor()
executor.xdecref(_evalcode_python(executor, input_type, global_dict, local_dict))
gdb.execute('set breakpoint pending on')
if hasattr(gdb, 'GdbError'):
# Wrap py-step and py-next in gdb defines to make them repeatable.
py_step = PyStep('-py-step', PythonInfo())
py_next = PyNext('-py-next', PythonInfo())
register_defines()
py_finish = PyFinish('py-finish', PythonInfo())
py_run = PyRun('py-run', PythonInfo())
py_cont = PyCont('py-cont', PythonInfo())
py_exec = FixGdbCommand('py-exec', '-py-exec')
_py_exec = PyExec("-py-exec", gdb.COMMAND_DATA, gdb.COMPLETE_NONE)
else:
warnings.warn("Use gdb 7.2 or higher to use the py-exec command.")