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Copy pathpython.cc
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479 lines (428 loc) · 14.7 KB
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#include <iostream>
#include "libpstack/elf.h"
#include <algorithm>
#include <stdlib.h>
#include <stddef.h>
#include "libpstack/dwarf.h"
#include "libpstack/proc.h"
#include "libpstack/python.h"
static bool
pthreadTidOffset(const Process &proc, size_t *offsetp)
{
static size_t offset;
static enum { notDone, notFound, found } status;
if (status == notDone) {
try {
auto addr = proc.findSymbolByName(0, "_thread_db_pthread_tid");
uint32_t desc[3];
proc.io->readObj(addr, &desc[0], 3);
offset = desc[2];
status = found;
if (verbose)
*debug << "found thread offset " << offset << "\n";
} catch (const std::exception &ex) {
if (verbose)
*debug << "failed to find offset of tid in pthread: " << ex.what();
status = notFound;
}
}
if (status == found) {
*offsetp = offset;
return true;
}
return false;
}
// This reimplements PyCode_Addr2Line
static int
getLine(const Reader &proc, const PyCodeObject *code, const PyFrameObject *frame)
{
PyVarObject lnotab;
proc.readObj(Elf::Addr(code->co_lnotab), &lnotab);
unsigned char linedata[lnotab.ob_size];
proc.readObj(Elf::Addr(code->co_lnotab) + offsetof(PyStringObject, ob_sval),
&linedata[0], lnotab.ob_size);
int line = code->co_firstlineno;
int addr = 0;
unsigned char *p = linedata;
unsigned char *e = linedata + lnotab.ob_size;
while (p < e) {
addr += *p++;
if (addr > frame->f_lasti) {
break;
}
line += *p++;
}
return line;
}
static Elf::Addr
heapPrint(const PyObject *, const PyTypeObject *pto, PythonPrinter *pc, Elf::Addr remote)
{
pc->os << pc->proc.io->readString(Elf::Addr(pto->tp_name));
if (pto->tp_dictoffset > 0) {
pc->os << "\n";
pc->depth++;
PyObject *dictAddr;
pc->proc.io->readObj(remote + pto->tp_dictoffset, &dictAddr);
pc->print(Elf::Addr(dictAddr));
pc->depth--;
pc->os << "\n";
}
return 0;
}
static Elf::Addr
stringPrint(const PyObject *pyo, const PyTypeObject *, PythonPrinter *pc, Elf::Addr)
{
auto *pso = (const PyStringObject *)pyo;
pc->os << "\"" << pso->ob_sval << "\"";
return 0;
}
static Elf::Addr
floatPrint(const PyObject *pyo, const PyTypeObject *, PythonPrinter *pc, Elf::Addr)
{
auto *pfo = (const PyFloatObject *)pyo;
pc->os << pfo->ob_fval;
return 0;
}
static Elf::Addr
intPrint(const PyObject *pyo, const PyTypeObject *, PythonPrinter *pc, Elf::Addr)
{
auto pio = (const PyIntObject *)pyo;
pc->os << pio->ob_ival;
return 0;
}
static Elf::Addr
boolPrint(const PyObject *pyo, const PyTypeObject *, PythonPrinter *pc, Elf::Addr)
{
auto pio = (const PyIntObject *)pyo;
pc->os << (pio->ob_ival ? "True" : "False");
return 0;
}
static Elf::Addr
modulePrint(const PyObject *, const PyTypeObject *, PythonPrinter *pc, Elf::Addr)
{
pc->os << "<python module>";
return 0;
}
static Elf::Addr
listPrint(const PyObject *po, const PyTypeObject *, PythonPrinter *pc, Elf::Addr)
{
auto plo = reinterpret_cast<const PyListObject *>(po);
pc->os << "list: \n";
auto size = std::min(plo->ob_size, Py_ssize_t(100));
PyObject *objects[size];
pc->proc.io->readObj(Elf::Addr(plo->ob_item), &objects[0], size);
pc->depth++;
for (auto addr : objects) {
pc->os << pc->prefix();
pc->print(Elf::Addr(addr));
pc->os << "\n";
}
pc->depth--;
pc->os << "\n";
return 0;
}
static Elf::Addr
classPrint(const PyObject *po, const PyTypeObject *, PythonPrinter *pc, Elf::Addr)
{
auto pco = reinterpret_cast<const PyClassObject *>(po);
pc->os << "<class ";
pc->print(Elf::Addr(pco->cl_name));
pc->os << ">";
return 0;
}
static Elf::Addr
dictPrint(const PyObject *pyo, const PyTypeObject *, PythonPrinter *pc, Elf::Addr)
{
PyDictObject *pdo = (PyDictObject *)pyo;
if (pdo->ma_used == 0)
return 0;
for (Py_ssize_t i = 0; i < pdo->ma_mask && i < 50; ++i) {
PyDictEntry pde = pc->proc.io->readObj<PyDictEntry>(Elf::Addr(pdo->ma_table + i));
if (pde.me_value == nullptr)
continue;
if (pde.me_key != nullptr) {
pc->os << pc->prefix();
pc->print(Elf::Addr(pde.me_key));
pc->os << ": ";
pc->print(Elf::Addr(pde.me_value));
pc->os << "\n";
}
}
return 0;
}
static Elf::Addr
typePrint(const PyObject *pyo, const PyTypeObject *, PythonPrinter *pc, Elf::Addr)
{
auto pto = (const _typeobject *)pyo;
pc->os << "type :\"" << pc->proc.io->readString(Elf::Addr(pto->tp_name)) << "\"";
return 0;
}
static Elf::Addr
instancePrint(const PyObject *pyo, const PyTypeObject *, PythonPrinter *pc, Elf::Addr)
{
const auto pio = reinterpret_cast<const PyInstanceObject *>(pyo);
pc->depth++;
pc->os << "\n" << pc->prefix() << "class: ";
pc->depth++;
pc->print(Elf::Addr(pio->in_class));
pc->depth--;
pc->os << "\n" << pc->prefix() << "dict: \n";
pc->depth++;
pc->print(Elf::Addr(pio->in_dict));
pc->depth--;
pc->depth--;
return 0;
}
static Elf::Addr
longPrint(const PyObject *pyo, const PyTypeObject *, PythonPrinter *pc, Elf::Addr)
{
auto plo = (PyLongObject *)pyo;
intmax_t value = 0;
for (int i = 0; i < plo->ob_size; ++i) {
value += intmax_t(plo->ob_digit[i]) << (PyLong_SHIFT * i) ;
}
pc->os << value;
return 0;
}
static int
printTupleVars(PythonPrinter *pc, Elf::Addr namesAddr, Elf::Addr valuesAddr, const char *type, Py_ssize_t maxvals = 1000000)
{
const auto &names = pc->proc.io->readObj<PyTupleObject>(namesAddr);
maxvals = std::min(names.ob_size, maxvals);
if (maxvals == 0)
return 0;
std::vector<PyObject *> varnames(maxvals);
std::vector<PyObject *> varvals(maxvals);
pc->proc.io->readObj(namesAddr + offsetof(PyTupleObject, ob_item), &varnames[0], maxvals);
pc->proc.io->readObj(valuesAddr, &varvals[0], maxvals);
pc->os << pc->prefix() << type <<":" << std::endl;
pc->depth++;
for (auto i = 0; i < maxvals; ++i) {
pc->os << pc->prefix();
pc->print(Elf::Addr(varnames[i]));
pc->os << "=";
pc->print(Elf::Addr(varvals[i]));
pc->os << "\n";
}
pc->depth--;
return maxvals;
}
static Elf::Addr
framePrint(const PyObject *pyo, const PyTypeObject *, PythonPrinter *pc, Elf::Addr remoteAddr)
{
auto pfo = (const PyFrameObject *)pyo;
if (pfo->f_code != 0) {
const auto &code = pc->proc.io->readObj<PyCodeObject>(Elf::Addr(pfo->f_code));
auto lineNo = getLine(*pc->proc.io, &code, pfo);
auto func = pc->proc.io->readString(Elf::Addr(code.co_name) + offsetof(PyStringObject, ob_sval));
auto file = pc->proc.io->readString(Elf::Addr(code.co_filename) + offsetof(PyStringObject, ob_sval));
pc->os << pc->prefix() << func << " in " << file << ":" << lineNo << "\n";
if (pc->options(PstackOptions::doargs)) {
Elf::Addr flocals = remoteAddr + offsetof(PyFrameObject, f_localsplus);
pc->depth++;
printTupleVars(pc, Elf::Addr(code.co_varnames), flocals, "fastlocals", code.co_nlocals);
flocals += code.co_nlocals * sizeof (PyObject *);
auto cellcount = printTupleVars(pc, Elf::Addr(code.co_cellvars), flocals, "cells");
flocals += cellcount * sizeof (PyObject *);
printTupleVars(pc, Elf::Addr(code.co_freevars), flocals, "freevars");
--pc->depth;
}
}
if (pc->options(PstackOptions::doargs) && pfo->f_locals != 0) {
pc->depth++;
pc->os << pc->prefix() << "locals: " << std::endl;
pc->print(Elf::Addr(pfo->f_locals));
pc->depth--;
}
return Elf::Addr(pfo->f_back);
}
const char *
PythonPrinter::prefix() const
{
static const char spaces[] =
" "
" "
" "
" "
" "
" ";
return spaces + sizeof spaces - 1 - depth * 4;
}
PyPrinterEntry::PyPrinterEntry(python_printfunc dumpfunc_, bool dupdetect_)
: printer(dumpfunc_)
, dupdetect(dupdetect_)
{
}
void
PythonPrinter::addPrinter(const char *symbol, python_printfunc func, bool dupDetect)
{
Elf::Sym sym;
if (!libPython->object->findSymbolByName(symbol, sym))
throw 999;
auto typeptr = sym.st_value + libPython->loadAddr;
printers.emplace(std::piecewise_construct, std::forward_as_tuple(typeptr), std::forward_as_tuple(func, dupDetect));
}
void
PythonPrinter::printStacks()
{
Elf::Addr ptr;
for (proc.io->readObj(interp_head, &ptr); ptr; )
ptr = printInterp(ptr);
}
PythonPrinter::PythonPrinter(Process &proc_, std::ostream &os_, const PstackOptions &options_)
: proc(proc_)
, os(os_)
, depth(0)
, libPython(nullptr)
, options(options_)
{
for (auto &o : proc.objects) {
std::string module = stringify(*o.object->io);
if (module.find("python") == std::string::npos)
continue;
auto dwarf = proc.imageCache.getDwarf(o.object);
if (!dwarf)
continue;
for (auto u : dwarf->getUnits()) {
// For each unit
for (const auto &compile : u->entries) {
if (compile.type->tag != Dwarf::DW_TAG_compile_unit)
continue;
// Do we have a global variable called interp_head?
for (const auto &rawvar : compile.children) {
Dwarf::DIERef var(u.get(), &rawvar);
if (var.die->type->tag == Dwarf::DW_TAG_variable && var.name() == "interp_head") {
Dwarf::ExpressionStack evalStack;
auto location = var.attribute(Dwarf::DW_AT_location);
if (!location.valid())
throw Exception() << "no DW_AT_location for interpreter";
interp_head = evalStack.eval(proc, location, 0, o.loadAddr);
libPython = &o;
break;
}
}
}
}
}
if (libPython == nullptr)
throw Exception() << "No libpython found";
std::clog << "python library is " << *libPython->object->io << std::endl;
addPrinter("PyString_Type", stringPrint, false);
addPrinter("PyDict_Type", dictPrint, true);
addPrinter("PyLong_Type", longPrint, false);
addPrinter("PyFrame_Type", framePrint, true);
addPrinter("PyInt_Type", intPrint, false);
addPrinter("PyType_Type", typePrint, false);
addPrinter("PyBool_Type", boolPrint, false);
addPrinter("PyInstance_Type", instancePrint, true);
addPrinter("PyModule_Type", modulePrint, false);
addPrinter("PyClass_Type", classPrint, false);
addPrinter("PyList_Type", listPrint, true);
addPrinter("PyFloat_Type", floatPrint, false);
heapPrinter = new PyPrinterEntry(heapPrint, true);
}
void
PythonPrinter::print(Elf::Addr remoteAddr)
{
if (depth > 10000) {
os << "too deep" << std::endl;
return;
}
depth++;
PyVarObject baseObj;
try {
while (remoteAddr) {
proc.io->readObj<PyVarObject> (remoteAddr, &baseObj);
if (baseObj.ob_refcnt == 0) {
os << "(dead object)";
break;
}
const PyPrinterEntry *printer = nullptr;
auto pi = printers.find(Elf::Addr(baseObj.ob_type));
if (pi != printers.end())
printer = &pi->second;
bool isNew = (types.find(Elf::Addr(baseObj.ob_type)) == types.end());
auto &pto = types[Elf::Addr(baseObj.ob_type)];
if (isNew) {
proc.io->readObj(Elf::Addr(Elf::Addr(baseObj.ob_type)), &pto);
}
if (printer == 0) {
std::string tn;
tn = proc.io->readString(Elf::Addr(pto.tp_name));
if (tn == "NoneType") {
os << "None";
break;
} else if (printer == 0 && (pto.tp_flags & Py_TPFLAGS_HEAPTYPE)) {
printer = heapPrinter;
} else {
os << remoteAddr << " unprintable-type-" << tn << "@"<< Elf::Addr(baseObj.ob_type);
break;
}
}
if (printer->dupdetect && visited.find(remoteAddr ) != visited.end()) {
os << "(already seen)";
break;
}
if (printer->dupdetect)
visited.insert(remoteAddr);
size_t size = pto.tp_basicsize;
size_t itemsize = pto.tp_itemsize;
ssize_t fullSize;
if (itemsize != 0) {
// object is a variable length object:
if (baseObj.ob_size > 65536 || baseObj.ob_size < 0) {
os << "(skip massive object " << baseObj.ob_size << ")";
break;
}
fullSize = size + itemsize * baseObj.ob_size;
} else {
fullSize = size;
}
char buf[fullSize];
proc.io->readObj(remoteAddr, buf, fullSize);
remoteAddr = printer->printer((const PyObject *)buf, &pto, this, remoteAddr);
}
}
catch (...) {
os << "(print failed)";
}
--depth;
}
/*
* process one python thread in an interpreter, at remote addr "ptr".
* returns the address of the next thread on the list.
*/
Elf::Addr
PythonPrinter::printThread(Elf::Addr ptr)
{
PyThreadState thread;
proc.io->readObj(ptr, &thread);
size_t toff;
if (thread.thread_id && pthreadTidOffset(proc, &toff)) {
Elf::Addr tidptr = thread.thread_id + toff;
pid_t tid;
proc.io->readObj(tidptr, &tid);
os << "pthread: 0x" << std::hex << thread.thread_id << std::dec << ", lwp " << tid;
} else {
os << "anonymous thread";
}
os << "\n";
print(Elf::Addr(thread.frame));
return Elf::Addr(thread.next);
}
/*
* Process one python interpreter in the process at remote address ptr
* Returns the address of the next interpreter on on the process's list.
*/
Elf::Addr
PythonPrinter::printInterp(Elf::Addr ptr)
{
PyInterpreterState state;
proc.io->readObj(ptr, &state);
os << "---- interpreter @" << std::hex << ptr << std::dec << " -----" << std::endl ;
for (Elf::Addr tsp = reinterpret_cast<Elf::Addr>(state.tstate_head); tsp; ) {
tsp = printThread(tsp);
os << std::endl;
}
return reinterpret_cast<Elf::Addr>(state.next);
}