#include "Python.h"

#include "pycore_initconfig.h" // _PyStatus_ERR

#include "pycore_pyerrors.h" // _Py_DumpExtensionModules

#include "pycore_pystate.h" // _PyThreadState_GET()

#include "pycore_signal.h" // Py_NSIG

#include "pycore_sysmodule.h" // _PySys_GetAttr()

#include "pycore_time.h" // _PyTime_FromSecondsObject()

#include "pycore_traceback.h" // _Py_DumpTracebackThreads

#ifdef HAVE_UNISTD_H

# include <unistd.h> // _exit()

#endif

#include <signal.h> // sigaction()

#include <stdlib.h> // abort()

#if defined(HAVE_PTHREAD_SIGMASK) && !defined(HAVE_BROKEN_PTHREAD_SIGMASK) && defined(HAVE_PTHREAD_H)

# include <pthread.h>

#endif

#ifdef MS_WINDOWS

# include <windows.h>

#endif

#ifdef HAVE_SYS_RESOURCE_H

# include <sys/resource.h> // setrlimit()

#endif

#if defined(FAULTHANDLER_USE_ALT_STACK) && defined(HAVE_LINUX_AUXVEC_H) && defined(HAVE_SYS_AUXV_H)

# include <linux/auxvec.h> // AT_MINSIGSTKSZ

# include <sys/auxv.h> // getauxval()

#endif

/* Allocate at maximum 100 MiB of the stack to raise the stack overflow */

#define STACK_OVERFLOW_MAX_SIZE (100 * 1024 * 1024)

#define PUTS(fd, str) (void)_Py_write_noraise(fd, str, strlen(str))

// clang uses __attribute__((no_sanitize("undefined")))

// GCC 4.9+ uses __attribute__((no_sanitize_undefined))

#if defined(__has_feature) // Clang

# if __has_feature(undefined_behavior_sanitizer)

# define _Py_NO_SANITIZE_UNDEFINED __attribute__((no_sanitize("undefined")))

# endif

#endif

#if defined(__GNUC__) \

&& ((__GNUC__ >= 5) || (__GNUC__ == 4) && (__GNUC_MINOR__ >= 9))

# define _Py_NO_SANITIZE_UNDEFINED __attribute__((no_sanitize_undefined))

#endif

#ifndef _Py_NO_SANITIZE_UNDEFINED

# define _Py_NO_SANITIZE_UNDEFINED

#endif

typedef struct {

int signum;

int enabled;

const char* name;

_Py_sighandler_t previous;

int all_threads;

} fault_handler_t;

#define fatal_error _PyRuntime.faulthandler.fatal_error

#define thread _PyRuntime.faulthandler.thread

#ifdef FAULTHANDLER_USER

#define user_signals _PyRuntime.faulthandler.user_signals

typedef struct faulthandler_user_signal user_signal_t;

static void faulthandler_user(int signum);

#endif /* FAULTHANDLER_USER */

static fault_handler_t faulthandler_handlers[] = {

#ifdef SIGBUS

{SIGBUS, 0, "Bus error", },

#endif

#ifdef SIGILL

{SIGILL, 0, "Illegal instruction", },

#endif

{SIGFPE, 0, "Floating point exception", },

{SIGABRT, 0, "Aborted", },

/* define SIGSEGV at the end to make it the default choice if searching the

handler fails in faulthandler_fatal_error() */

{SIGSEGV, 0, "Segmentation fault", }

};

static const size_t faulthandler_nsignals = \

Py_ARRAY_LENGTH(faulthandler_handlers);

#ifdef FAULTHANDLER_USE_ALT_STACK

# define stack _PyRuntime.faulthandler.stack

# define old_stack _PyRuntime.faulthandler.old_stack

#endif

/* Get the file descriptor of a file by calling its fileno() method and then

call its flush() method.

If file is NULL or Py_None, use sys.stderr as the new file.

If file is an integer, it will be treated as file descriptor.

On success, return the file descriptor and write the new file into *file_ptr.

On error, return -1. */

static int

faulthandler_get_fileno(PyObject **file_ptr)

{

PyObject *result;

long fd_long;

int fd;

PyObject *file = *file_ptr;

if (file == NULL || file == Py_None) {

PyThreadState *tstate = _PyThreadState_GET();

file = _PySys_GetAttr(tstate, &_Py_ID(stderr));

if (file == NULL) {

PyErr_SetString(PyExc_RuntimeError, "unable to get sys.stderr");

return -1;

}

if (file == Py_None) {

PyErr_SetString(PyExc_RuntimeError, "sys.stderr is None");

return -1;

}

}

else if (PyLong_Check(file)) {

if (PyBool_Check(file)) {

if (PyErr_WarnEx(PyExc_RuntimeWarning,

"bool is used as a file descriptor", 1))

{

return -1;

}

}

fd = PyLong_AsInt(file);

if (fd == -1 && PyErr_Occurred())

return -1;

if (fd < 0) {

PyErr_SetString(PyExc_ValueError,

"file is not a valid file descriptor");

return -1;

}

*file_ptr = NULL;

return fd;

}

result = PyObject_CallMethodNoArgs(file, &_Py_ID(fileno));

if (result == NULL)

return -1;

fd = -1;

if (PyLong_Check(result)) {

fd_long = PyLong_AsLong(result);

if (0 <= fd_long && fd_long < INT_MAX)

fd = (int)fd_long;

}

Py_DECREF(result);

if (fd == -1) {

PyErr_SetString(PyExc_RuntimeError,

"file.fileno() is not a valid file descriptor");

return -1;

}

if (_PyFile_Flush(file) < 0) {

/* ignore flush() error */

PyErr_Clear();

}

*file_ptr = file;

return fd;

}

/* Get the state of the current thread: only call this function if the current

thread holds the GIL. Raise an exception on error. */

static PyThreadState*

get_thread_state(void)

{

PyThreadState *tstate = _PyThreadState_GET();

if (tstate == NULL) {

/* just in case but very unlikely... */

PyErr_SetString(PyExc_RuntimeError,

"unable to get the current thread state");

return NULL;

}

return tstate;

}

static void

faulthandler_dump_traceback(int fd, int all_threads,

PyInterpreterState *interp)

{

static volatile int reentrant = 0;

if (reentrant)

return;

reentrant = 1;

/* SIGSEGV, SIGFPE, SIGABRT, SIGBUS and SIGILL are synchronous signals and

are thus delivered to the thread that caused the fault. Get the Python

thread state of the current thread.

PyThreadState_Get() doesn't give the state of the thread that caused the

fault if the thread released the GIL, and so this function cannot be

used. Read the thread specific storage (TSS) instead: call

PyGILState_GetThisThreadState(). */

PyThreadState *tstate = PyGILState_GetThisThreadState();

if (all_threads) {

(void)_Py_DumpTracebackThreads(fd, NULL, tstate);

}

else {

if (tstate != NULL)

_Py_DumpTraceback(fd, tstate);

}

reentrant = 0;

}

static PyObject*

faulthandler_dump_traceback_py(PyObject *self,

PyObject *args, PyObject *kwargs)

{

static char *kwlist[] = {"file", "all_threads", NULL};

PyObject *file = NULL;

int all_threads = 1;

PyThreadState *tstate;

const char *errmsg;

int fd;

if (!PyArg_ParseTupleAndKeywords(args, kwargs,

"|Op:dump_traceback", kwlist,

&file, &all_threads))

return NULL;

fd = faulthandler_get_fileno(&file);

if (fd < 0)

return NULL;

tstate = get_thread_state();

if (tstate == NULL)

return NULL;

if (all_threads) {

errmsg = _Py_DumpTracebackThreads(fd, NULL, tstate);

if (errmsg != NULL) {

PyErr_SetString(PyExc_RuntimeError, errmsg);

return NULL;

}

}

else {

_Py_DumpTraceback(fd, tstate);

}

if (PyErr_CheckSignals())

return NULL;

Py_RETURN_NONE;

}

static void

faulthandler_disable_fatal_handler(fault_handler_t *handler)

{

if (!handler->enabled)

return;

handler->enabled = 0;

#ifdef HAVE_SIGACTION

(void)sigaction(handler->signum, &handler->previous, NULL);

#else

(void)signal(handler->signum, handler->previous);

#endif

}

/* Handler for SIGSEGV, SIGFPE, SIGABRT, SIGBUS and SIGILL signals.

Display the current Python traceback, restore the previous handler and call

the previous handler.

On Windows, don't explicitly call the previous handler, because the Windows

signal handler would not be called (for an unknown reason). The execution of

the program continues at faulthandler_fatal_error() exit, but the same

instruction will raise the same fault (signal), and so the previous handler

will be called.

This function is signal-safe and should only call signal-safe functions. */

static void

faulthandler_fatal_error(int signum)

{

const int fd = fatal_error.fd;

size_t i;

fault_handler_t *handler = NULL;

int save_errno = errno;

int found = 0;

if (!fatal_error.enabled)

return;

for (i=0; i < faulthandler_nsignals; i++) {

handler = &faulthandler_handlers[i];

if (handler->signum == signum) {

found = 1;

break;

}

}

if (handler == NULL) {

/* faulthandler_nsignals == 0 (unlikely) */

return;

}

/* restore the previous handler */

faulthandler_disable_fatal_handler(handler);

if (found) {

PUTS(fd, "Fatal Python error: ");

PUTS(fd, handler->name);

PUTS(fd, "\n\n");

}

else {

char unknown_signum[23] = {0,};

snprintf(unknown_signum, 23, "%d", signum);

PUTS(fd, "Fatal Python error from unexpected signum: ");

PUTS(fd, unknown_signum);

PUTS(fd, "\n\n");

}

faulthandler_dump_traceback(fd, fatal_error.all_threads,

fatal_error.interp);

_Py_DumpExtensionModules(fd, fatal_error.interp);

errno = save_errno;

#ifdef MS_WINDOWS

if (signum == SIGSEGV) {

/* don't explicitly call the previous handler for SIGSEGV in this signal

handler, because the Windows signal handler would not be called */

return;

}

#endif

/* call the previous signal handler: it is called immediately if we use

sigaction() thanks to SA_NODEFER flag, otherwise it is deferred */

raise(signum);

}

#ifdef MS_WINDOWS

static int

faulthandler_ignore_exception(DWORD code)

{

/* bpo-30557: ignore exceptions which are not errors */

if (!(code & 0x80000000)) {

return 1;

}

/* bpo-31701: ignore MSC and COM exceptions

E0000000 + code */

if (code == 0xE06D7363 /* MSC exception ("Emsc") */

|| code == 0xE0434352 /* COM Callable Runtime exception ("ECCR") */) {

return 1;

}

/* Interesting exception: log it with the Python traceback */

return 0;

}

static LONG WINAPI

faulthandler_exc_handler(struct _EXCEPTION_POINTERS *exc_info)

{

const int fd = fatal_error.fd;

DWORD code = exc_info->ExceptionRecord->ExceptionCode;

DWORD flags = exc_info->ExceptionRecord->ExceptionFlags;

if (faulthandler_ignore_exception(code)) {

/* ignore the exception: call the next exception handler */

return EXCEPTION_CONTINUE_SEARCH;

}

PUTS(fd, "Windows fatal exception: ");

switch (code)

{

/* only format most common errors */

case EXCEPTION_ACCESS_VIOLATION: PUTS(fd, "access violation"); break;

case EXCEPTION_FLT_DIVIDE_BY_ZERO: PUTS(fd, "float divide by zero"); break;

case EXCEPTION_FLT_OVERFLOW: PUTS(fd, "float overflow"); break;

case EXCEPTION_INT_DIVIDE_BY_ZERO: PUTS(fd, "int divide by zero"); break;

case EXCEPTION_INT_OVERFLOW: PUTS(fd, "integer overflow"); break;

case EXCEPTION_IN_PAGE_ERROR: PUTS(fd, "page error"); break;

case EXCEPTION_STACK_OVERFLOW: PUTS(fd, "stack overflow"); break;

default:

PUTS(fd, "code 0x");

_Py_DumpHexadecimal(fd, code, 8);

}

PUTS(fd, "\n\n");

if (code == EXCEPTION_ACCESS_VIOLATION) {

/* disable signal handler for SIGSEGV */

for (size_t i=0; i < faulthandler_nsignals; i++) {

fault_handler_t *handler = &faulthandler_handlers[i];

if (handler->signum == SIGSEGV) {

faulthandler_disable_fatal_handler(handler);

break;

}

}

}

faulthandler_dump_traceback(fd, fatal_error.all_threads,

fatal_error.interp);

/* call the next exception handler */

return EXCEPTION_CONTINUE_SEARCH;

}

#endif

#ifdef FAULTHANDLER_USE_ALT_STACK

static int

faulthandler_allocate_stack(void)

{

if (stack.ss_sp != NULL) {

return 0;

}

/* Allocate an alternate stack for faulthandler() signal handler

to be able to execute a signal handler on a stack overflow error */

stack.ss_sp = PyMem_Malloc(stack.ss_size);

if (stack.ss_sp == NULL) {

PyErr_NoMemory();

return -1;

}

int err = sigaltstack(&stack, &old_stack);

if (err) {

PyErr_SetFromErrno(PyExc_OSError);

/* Release the stack to retry sigaltstack() next time */

PyMem_Free(stack.ss_sp);

stack.ss_sp = NULL;

return -1;

}

return 0;

}

#endif

/* Install the handler for fatal signals, faulthandler_fatal_error(). */

static int

faulthandler_enable(void)

{

if (fatal_error.enabled) {

return 0;

}

fatal_error.enabled = 1;

#ifdef FAULTHANDLER_USE_ALT_STACK

if (faulthandler_allocate_stack() < 0) {

return -1;

}

#endif

for (size_t i=0; i < faulthandler_nsignals; i++) {

fault_handler_t *handler;

int err;

handler = &faulthandler_handlers[i];

assert(!handler->enabled);

#ifdef HAVE_SIGACTION

struct sigaction action;

action.sa_handler = faulthandler_fatal_error;

sigemptyset(&action.sa_mask);

/* Do not prevent the signal from being received from within

its own signal handler */

action.sa_flags = SA_NODEFER;

#ifdef FAULTHANDLER_USE_ALT_STACK

assert(stack.ss_sp != NULL);

/* Call the signal handler on an alternate signal stack

provided by sigaltstack() */

action.sa_flags |= SA_ONSTACK;

#endif

err = sigaction(handler->signum, &action, &handler->previous);

#else

handler->previous = signal(handler->signum,

faulthandler_fatal_error);

err = (handler->previous == SIG_ERR);

#endif

if (err) {

PyErr_SetFromErrno(PyExc_RuntimeError);

return -1;

}

handler->enabled = 1;

}

#ifdef MS_WINDOWS

assert(fatal_error.exc_handler == NULL);

fatal_error.exc_handler = AddVectoredExceptionHandler(1, faulthandler_exc_handler);

#endif

return 0;

}

static PyObject*

faulthandler_py_enable(PyObject *self, PyObject *args, PyObject *kwargs)

{

static char *kwlist[] = {"file", "all_threads", NULL};

PyObject *file = NULL;

int all_threads = 1;

int fd;

PyThreadState *tstate;

if (!PyArg_ParseTupleAndKeywords(args, kwargs,

"|Op:enable", kwlist, &file, &all_threads))

return NULL;

fd = faulthandler_get_fileno(&file);

if (fd < 0)

return NULL;

tstate = get_thread_state();

if (tstate == NULL)

return NULL;

Py_XINCREF(file);

Py_XSETREF(fatal_error.file, file);

fatal_error.fd = fd;

fatal_error.all_threads = all_threads;

fatal_error.interp = PyThreadState_GetInterpreter(tstate);

if (faulthandler_enable() < 0) {

return NULL;

}

Py_RETURN_NONE;

}

static void

faulthandler_disable(void)

{

if (fatal_error.enabled) {

fatal_error.enabled = 0;

for (size_t i=0; i < faulthandler_nsignals; i++) {

fault_handler_t *handler;

handler = &faulthandler_handlers[i];

faulthandler_disable_fatal_handler(handler);

}

}

#ifdef MS_WINDOWS

if (fatal_error.exc_handler != NULL) {

RemoveVectoredExceptionHandler(fatal_error.exc_handler);

fatal_error.exc_handler = NULL;

}

#endif

Py_CLEAR(fatal_error.file);

}

static PyObject*

faulthandler_disable_py(PyObject *self, PyObject *Py_UNUSED(ignored))

{

if (!fatal_error.enabled) {

Py_RETURN_FALSE;

}

faulthandler_disable();

Py_RETURN_TRUE;

}

static PyObject*

faulthandler_is_enabled(PyObject *self, PyObject *Py_UNUSED(ignored))

{

return PyBool_FromLong(fatal_error.enabled);

}

static void

faulthandler_thread(void *unused)

{

PyLockStatus st;

const char* errmsg;

int ok;

#if defined(HAVE_PTHREAD_SIGMASK) && !defined(HAVE_BROKEN_PTHREAD_SIGMASK)

sigset_t set;

/* we don't want to receive any signal */

sigfillset(&set);

pthread_sigmask(SIG_SETMASK, &set, NULL);

#endif

do {

st = PyThread_acquire_lock_timed(thread.cancel_event,

thread.timeout_us, 0);

if (st == PY_LOCK_ACQUIRED) {

PyThread_release_lock(thread.cancel_event);

break;

}

/* Timeout => dump traceback */

assert(st == PY_LOCK_FAILURE);

(void)_Py_write_noraise(thread.fd, thread.header, (int)thread.header_len);

errmsg = _Py_DumpTracebackThreads(thread.fd, thread.interp, NULL);

ok = (errmsg == NULL);

if (thread.exit)

_exit(1);

} while (ok && thread.repeat);

/* The only way out */

PyThread_release_lock(thread.running);

}

static void

cancel_dump_traceback_later(void)

{

/* If not scheduled, nothing to cancel */

if (!thread.cancel_event) {

return;

}

/* Notify cancellation */

PyThread_release_lock(thread.cancel_event);

/* Wait for thread to join */

PyThread_acquire_lock(thread.running, 1);

PyThread_release_lock(thread.running);

/* The main thread should always hold the cancel_event lock */

PyThread_acquire_lock(thread.cancel_event, 1);

Py_CLEAR(thread.file);

if (thread.header) {

PyMem_Free(thread.header);

thread.header = NULL;

}

}

#define SEC_TO_US (1000 * 1000)

static char*

format_timeout(PyTime_t us)

{

unsigned long sec, min, hour;

char buffer[100];

/* the downcast is safe: the caller check that 0 < us <= LONG_MAX */

sec = (unsigned long)(us / SEC_TO_US);

us %= SEC_TO_US;

min = sec / 60;

sec %= 60;

hour = min / 60;

min %= 60;

if (us != 0) {

PyOS_snprintf(buffer, sizeof(buffer),

"Timeout (%lu:%02lu:%02lu.%06u)!\n",

hour, min, sec, (unsigned int)us);

}

else {

PyOS_snprintf(buffer, sizeof(buffer),

"Timeout (%lu:%02lu:%02lu)!\n",

hour, min, sec);

}

return _PyMem_Strdup(buffer);

}

static PyObject*

faulthandler_dump_traceback_later(PyObject *self,

PyObject *args, PyObject *kwargs)

{

static char *kwlist[] = {"timeout", "repeat", "file", "exit", NULL};

PyObject *timeout_obj;

PyTime_t timeout, timeout_us;

int repeat = 0;

PyObject *file = NULL;

int fd;

int exit = 0;

PyThreadState *tstate;

char *header;

size_t header_len;

if (!PyArg_ParseTupleAndKeywords(args, kwargs,

"O|iOi:dump_traceback_later", kwlist,

&timeout_obj, &repeat, &file, &exit))

return NULL;

if (_PyTime_FromSecondsObject(&timeout, timeout_obj,

_PyTime_ROUND_TIMEOUT) < 0) {

return NULL;

}

timeout_us = _PyTime_AsMicroseconds(timeout, _PyTime_ROUND_TIMEOUT);

if (timeout_us <= 0) {

PyErr_SetString(PyExc_ValueError, "timeout must be greater than 0");

return NULL;

}

/* Limit to LONG_MAX seconds for format_timeout() */

if (timeout_us > PY_TIMEOUT_MAX || timeout_us / SEC_TO_US > LONG_MAX) {

PyErr_SetString(PyExc_OverflowError,

"timeout value is too large");

return NULL;

}

tstate = get_thread_state();

if (tstate == NULL) {

return NULL;

}

fd = faulthandler_get_fileno(&file);

if (fd < 0) {

return NULL;

}

if (!thread.running) {

thread.running = PyThread_allocate_lock();

if (!thread.running) {

return PyErr_NoMemory();

}

}

if (!thread.cancel_event) {

thread.cancel_event = PyThread_allocate_lock();

if (!thread.cancel_event || !thread.running) {

return PyErr_NoMemory();

}

/* cancel_event starts to be acquired: it's only released to cancel

the thread. */

PyThread_acquire_lock(thread.cancel_event, 1);

}

/* format the timeout */

header = format_timeout(timeout_us);

if (header == NULL) {

return PyErr_NoMemory();

}

header_len = strlen(header);

/* Cancel previous thread, if running */

cancel_dump_traceback_later();

Py_XINCREF(file);

Py_XSETREF(thread.file, file);

thread.fd = fd;

/* the downcast is safe: we check that 0 < timeout_us < PY_TIMEOUT_MAX */

thread.timeout_us = (PY_TIMEOUT_T)timeout_us;

thread.repeat = repeat;

thread.interp = PyThreadState_GetInterpreter(tstate);

thread.exit = exit;

thread.header = header;

thread.header_len = header_len;

/* Arm these locks to serve as events when released */

PyThread_acquire_lock(thread.running, 1);

if (PyThread_start_new_thread(faulthandler_thread, NULL) == PYTHREAD_INVALID_THREAD_ID) {

PyThread_release_lock(thread.running);

Py_CLEAR(thread.file);

PyMem_Free(header);

thread.header = NULL;

PyErr_SetString(PyExc_RuntimeError,

"unable to start watchdog thread");

return NULL;

}

Py_RETURN_NONE;

}

static PyObject*

faulthandler_cancel_dump_traceback_later_py(PyObject *self,

PyObject *Py_UNUSED(ignored))

{

cancel_dump_traceback_later();

Py_RETURN_NONE;

}

#ifdef FAULTHANDLER_USER

static int

faulthandler_register(int signum, int chain, _Py_sighandler_t *previous_p)

{

#ifdef HAVE_SIGACTION

struct sigaction action;

action.sa_handler = faulthandler_user;

sigemptyset(&action.sa_mask);

/* if the signal is received while the kernel is executing a system

call, try to restart the system call instead of interrupting it and

return EINTR. */

action.sa_flags = SA_RESTART;

if (chain) {

/* do not prevent the signal from being received from within its

own signal handler */

action.sa_flags = SA_NODEFER;

}

#ifdef FAULTHANDLER_USE_ALT_STACK

assert(stack.ss_sp != NULL);

/* Call the signal handler on an alternate signal stack

provided by sigaltstack() */

action.sa_flags |= SA_ONSTACK;

#endif

return sigaction(signum, &action, previous_p);

#else

_Py_sighandler_t previous;

previous = signal(signum, faulthandler_user);

if (previous_p != NULL) {

*previous_p = previous;

}

return (previous == SIG_ERR);

#endif

}

/* Handler of user signals (e.g. SIGUSR1).

Dump the traceback of the current thread, or of all threads if

thread.all_threads is true.

This function is signal safe and should only call signal safe functions. */

static void

faulthandler_user(int signum)

{

user_signal_t *user;

int save_errno = errno;

user = &user_signals[signum];

if (!user->enabled)

return;

faulthandler_dump_traceback(user->fd, user->all_threads, user->interp);

#ifdef HAVE_SIGACTION

if (user->chain) {

(void)sigaction(signum, &user->previous, NULL);

errno = save_errno;

/* call the previous signal handler */

raise(signum);

save_errno = errno;

(void)faulthandler_register(signum, user->chain, NULL);

errno = save_errno;

}

#else

if (user->chain && user->previous != NULL) {

errno = save_errno;

/* call the previous signal handler */

user->previous(signum);

}

#endif

}

static int

check_signum(int signum)

{

for (size_t i=0; i < faulthandler_nsignals; i++) {

if (faulthandler_handlers[i].signum == signum) {

PyErr_Format(PyExc_RuntimeError,

"signal %i cannot be registered, "

"use enable() instead",

signum);

return 0;

}

}

if (signum < 1 || Py_NSIG <= signum) {

PyErr_SetString(PyExc_ValueError, "signal number out of range");

return 0;

}

return 1;

}

static PyObject*

faulthandler_register_py(PyObject *self,

PyObject *args, PyObject *kwargs)

{

static char *kwlist[] = {"signum", "file", "all_threads", "chain", NULL};

int signum;

PyObject *file = NULL;

int all_threads = 1;

int chain = 0;

int fd;

user_signal_t *user;

_Py_sighandler_t previous;

PyThreadState *tstate;

int err;

if (!PyArg_ParseTupleAndKeywords(args, kwargs,

"i|Opp:register", kwlist,

&signum, &file, &all_threads, &chain))

return NULL;

if (!check_signum(signum))

return NULL;

tstate = get_thread_state();

if (tstate == NULL)

return NULL;

fd = faulthandler_get_fileno(&file);

if (fd < 0)

return NULL;

if (user_signals == NULL) {

user_signals = PyMem_Calloc(Py_NSIG, sizeof(user_signal_t));

if (user_signals == NULL)

return PyErr_NoMemory();

}

user = &user_signals[signum];

if (!user->enabled) {

#ifdef FAULTHANDLER_USE_ALT_STACK

if (faulthandler_allocate_stack() < 0) {

return NULL;

}

#endif

err = faulthandler_register(signum, chain, &previous);

if (err) {

PyErr_SetFromErrno(PyExc_OSError);

return NULL;

}

user->previous = previous;

}

Py_XINCREF(file);

Py_XSETREF(user->file, file);

user->fd = fd;

user->all_threads = all_threads;

user->chain = chain;

user->interp = PyThreadState_GetInterpreter(tstate);

user->enabled = 1;

Py_RETURN_NONE;

}

static int

faulthandler_unregister(user_signal_t *user, int signum)

{

if (!user->enabled)

return 0;

user->enabled = 0;

#ifdef HAVE_SIGACTION

(void)sigaction(signum, &user->previous, NULL);

#else

(void)signal(signum, user->previous);

#endif

Py_CLEAR(user->file);

user->fd = -1;

return 1;

}

static PyObject*

faulthandler_unregister_py(PyObject *self, PyObject *args)

{

int signum;

user_signal_t *user;

int change;

if (!PyArg_ParseTuple(args, "i:unregister", &signum))

return NULL;

if (!check_signum(signum))

return NULL;

if (user_signals == NULL)

Py_RETURN_FALSE;

user = &user_signals[signum];

change = faulthandler_unregister(user, signum);

return PyBool_FromLong(change);

}

#endif /* FAULTHANDLER_USER */

static void

faulthandler_suppress_crash_report(void)

{

#ifdef MS_WINDOWS_DESKTOP

UINT mode;

/* Configure Windows to not display the Windows Error Reporting dialog */

mode = SetErrorMode(SEM_NOGPFAULTERRORBOX);

SetErrorMode(mode | SEM_NOGPFAULTERRORBOX);

#endif

#ifdef HAVE_SYS_RESOURCE_H

struct rlimit rl;

/* Disable creation of core dump */

if (getrlimit(RLIMIT_CORE, &rl) == 0) {

rl.rlim_cur = 0;

setrlimit(RLIMIT_CORE, &rl);

}

#endif

#ifdef _MSC_VER

/* Visual Studio: configure abort() to not display an error message nor

open a popup asking to report the fault. */

_set_abort_behavior(0, _WRITE_ABORT_MSG | _CALL_REPORTFAULT);

#endif

}

static PyObject* _Py_NO_SANITIZE_UNDEFINED

faulthandler_read_null(PyObject *self, PyObject *args)

{

volatile int *x;

volatile int y;

faulthandler_suppress_crash_report();

x = NULL;

y = *x;

return PyLong_FromLong(y);

}