/* Traceback implementation */

#include "Python.h"

#include "code.h"

#include "frameobject.h"

#include "structmember.h"

#include "osdefs.h"

#ifdef HAVE_FCNTL_H

#include <fcntl.h>

#endif

#define OFF(x) offsetof(PyTracebackObject, x)

#define PUTS(fd, str) write(fd, str, (int)strlen(str))

#define MAX_STRING_LENGTH 500

#define MAX_FRAME_DEPTH 100

#define MAX_NTHREADS 100

/* Function from Parser/tokenizer.c */

extern char * PyTokenizer_FindEncodingFilename(int, PyObject *);

static PyObject *

tb_dir(PyTracebackObject *self)

{

return Py_BuildValue("[ssss]", "tb_frame", "tb_next",

"tb_lasti", "tb_lineno");

}

static PyMethodDef tb_methods[] = {

{"__dir__", (PyCFunction)tb_dir, METH_NOARGS},

{NULL, NULL, 0, NULL},

};

static PyMemberDef tb_memberlist[] = {

{"tb_next", T_OBJECT, OFF(tb_next), READONLY},

{"tb_frame", T_OBJECT, OFF(tb_frame), READONLY},

{"tb_lasti", T_INT, OFF(tb_lasti), READONLY},

{"tb_lineno", T_INT, OFF(tb_lineno), READONLY},

{NULL} /* Sentinel */

};

static void

tb_dealloc(PyTracebackObject *tb)

{

PyObject_GC_UnTrack(tb);

Py_TRASHCAN_SAFE_BEGIN(tb)

Py_XDECREF(tb->tb_next);

Py_XDECREF(tb->tb_frame);

PyObject_GC_Del(tb);

Py_TRASHCAN_SAFE_END(tb)

}

static int

tb_traverse(PyTracebackObject *tb, visitproc visit, void *arg)

{

Py_VISIT(tb->tb_next);

Py_VISIT(tb->tb_frame);

return 0;

}

static void

tb_clear(PyTracebackObject *tb)

{

Py_CLEAR(tb->tb_next);

Py_CLEAR(tb->tb_frame);

}

PyTypeObject PyTraceBack_Type = {

PyVarObject_HEAD_INIT(&PyType_Type, 0)

"traceback",

sizeof(PyTracebackObject),

0,

(destructor)tb_dealloc, /*tp_dealloc*/

0, /*tp_print*/

0, /*tp_getattr*/

0, /*tp_setattr*/

0, /*tp_reserved*/

0, /*tp_repr*/

0, /*tp_as_number*/

0, /*tp_as_sequence*/

0, /*tp_as_mapping*/

0, /* tp_hash */

0, /* tp_call */

0, /* tp_str */

PyObject_GenericGetAttr, /* tp_getattro */

0, /* tp_setattro */

0, /* tp_as_buffer */

Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */

0, /* tp_doc */

(traverseproc)tb_traverse, /* tp_traverse */

(inquiry)tb_clear, /* tp_clear */

0, /* tp_richcompare */

0, /* tp_weaklistoffset */

0, /* tp_iter */

0, /* tp_iternext */

tb_methods, /* tp_methods */

tb_memberlist, /* tp_members */

0, /* tp_getset */

0, /* tp_base */

0, /* tp_dict */

};

static PyTracebackObject *

newtracebackobject(PyTracebackObject *next, PyFrameObject *frame)

{

PyTracebackObject *tb;

if ((next != NULL && !PyTraceBack_Check(next)) ||

frame == NULL || !PyFrame_Check(frame)) {

PyErr_BadInternalCall();

return NULL;

}

tb = PyObject_GC_New(PyTracebackObject, &PyTraceBack_Type);

if (tb != NULL) {

Py_XINCREF(next);

tb->tb_next = next;

Py_XINCREF(frame);

tb->tb_frame = frame;

tb->tb_lasti = frame->f_lasti;

tb->tb_lineno = PyFrame_GetLineNumber(frame);

PyObject_GC_Track(tb);

}

return tb;

}

int

PyTraceBack_Here(PyFrameObject *frame)

{

PyThreadState *tstate = PyThreadState_GET();

PyTracebackObject *oldtb = (PyTracebackObject *) tstate->curexc_traceback;

PyTracebackObject *tb = newtracebackobject(oldtb, frame);

if (tb == NULL)

return -1;

tstate->curexc_traceback = (PyObject *)tb;

Py_XDECREF(oldtb);

return 0;

}

static PyObject *

_Py_FindSourceFile(PyObject *filename, char* namebuf, size_t namelen, PyObject *io)

{

Py_ssize_t i;

PyObject *binary;

PyObject *v;

Py_ssize_t npath;

size_t taillen;

PyObject *syspath;

PyObject *path;

const char* tail;

PyObject *filebytes;

const char* filepath;

Py_ssize_t len;

PyObject* result;

_Py_IDENTIFIER(open);

filebytes = PyUnicode_EncodeFSDefault(filename);

if (filebytes == NULL) {

PyErr_Clear();

return NULL;

}

filepath = PyBytes_AS_STRING(filebytes);

/* Search tail of filename in sys.path before giving up */

tail = strrchr(filepath, SEP);

if (tail == NULL)

tail = filepath;

else

tail++;

taillen = strlen(tail);

syspath = PySys_GetObject("path");

if (syspath == NULL || !PyList_Check(syspath))

goto error;

npath = PyList_Size(syspath);

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

v = PyList_GetItem(syspath, i);

if (v == NULL) {

PyErr_Clear();

break;

}

if (!PyUnicode_Check(v))

continue;

path = PyUnicode_EncodeFSDefault(v);

if (path == NULL) {

PyErr_Clear();

continue;

}

len = PyBytes_GET_SIZE(path);

if (len + 1 + (Py_ssize_t)taillen >= (Py_ssize_t)namelen - 1) {

Py_DECREF(path);

continue; /* Too long */

}

strcpy(namebuf, PyBytes_AS_STRING(path));

Py_DECREF(path);

if (strlen(namebuf) != len)

continue; /* v contains '\0' */

if (len > 0 && namebuf[len-1] != SEP)

namebuf[len++] = SEP;

strcpy(namebuf+len, tail);

binary = _PyObject_CallMethodId(io, &PyId_open, "ss", namebuf, "rb");

if (binary != NULL) {

result = binary;

goto finally;

}

PyErr_Clear();

}

goto error;

error:

result = NULL;

finally:

Py_DECREF(filebytes);

return result;

}

int

_Py_DisplaySourceLine(PyObject *f, PyObject *filename, int lineno, int indent)

{

int err = 0;

int fd;

int i;

char *found_encoding;

char *encoding;

PyObject *io;

PyObject *binary;

PyObject *fob = NULL;

PyObject *lineobj = NULL;

PyObject *res;

char buf[MAXPATHLEN+1];

int kind;

void *data;

_Py_IDENTIFIER(close);

_Py_IDENTIFIER(open);

_Py_IDENTIFIER(TextIOWrapper);

/* open the file */

if (filename == NULL)

return 0;

io = PyImport_ImportModuleNoBlock("io");

if (io == NULL)

return -1;

binary = _PyObject_CallMethodId(io, &PyId_open, "Os", filename, "rb");

if (binary == NULL) {

PyErr_Clear();

binary = _Py_FindSourceFile(filename, buf, sizeof(buf), io);

if (binary == NULL) {

Py_DECREF(io);

return -1;

}

}

/* use the right encoding to decode the file as unicode */

fd = PyObject_AsFileDescriptor(binary);

if (fd < 0) {

Py_DECREF(io);

Py_DECREF(binary);

return 0;

}

found_encoding = PyTokenizer_FindEncodingFilename(fd, filename);

encoding = (found_encoding != NULL) ? found_encoding : "utf-8";

/* Reset position */

if (lseek(fd, 0, SEEK_SET) == (off_t)-1) {

Py_DECREF(io);

Py_DECREF(binary);

PyMem_FREE(found_encoding);

return 0;

}

fob = _PyObject_CallMethodId(io, &PyId_TextIOWrapper, "Os", binary, encoding);

Py_DECREF(io);

Py_DECREF(binary);

PyMem_FREE(found_encoding);

if (fob == NULL) {

PyErr_Clear();

return 0;

}

/* get the line number lineno */

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

Py_XDECREF(lineobj);

lineobj = PyFile_GetLine(fob, -1);

if (!lineobj) {

err = -1;

break;

}

}

res = _PyObject_CallMethodId(fob, &PyId_close, "");

if (res)

Py_DECREF(res);

else

PyErr_Clear();

Py_DECREF(fob);

if (!lineobj || !PyUnicode_Check(lineobj)) {

Py_XDECREF(lineobj);

return err;

}

/* remove the indentation of the line */

kind = PyUnicode_KIND(lineobj);

data = PyUnicode_DATA(lineobj);

for (i=0; i < PyUnicode_GET_LENGTH(lineobj); i++) {

Py_UCS4 ch = PyUnicode_READ(kind, data, i);

if (ch != ' ' && ch != '\t' && ch != '\014')

break;

}

if (i) {

PyObject *truncated;

truncated = PyUnicode_Substring(lineobj, i, PyUnicode_GET_LENGTH(lineobj));

if (truncated) {

Py_DECREF(lineobj);

lineobj = truncated;

} else {

PyErr_Clear();

}

}

/* Write some spaces before the line */

strcpy(buf, " ");

assert (strlen(buf) == 10);

while (indent > 0) {

if (indent < 10)

buf[indent] = '\0';

err = PyFile_WriteString(buf, f);

if (err != 0)

break;

indent -= 10;

}

/* finally display the line */

if (err == 0)

err = PyFile_WriteObject(lineobj, f, Py_PRINT_RAW);

Py_DECREF(lineobj);

if (err == 0)

err = PyFile_WriteString("\n", f);

return err;

}

static int

tb_displayline(PyObject *f, PyObject *filename, int lineno, PyObject *name)

{

int err;

PyObject *line;

if (filename == NULL || name == NULL)

return -1;

line = PyUnicode_FromFormat(" File \"%U\", line %d, in %U\n",

filename, lineno, name);

if (line == NULL)

return -1;

err = PyFile_WriteObject(line, f, Py_PRINT_RAW);

Py_DECREF(line);

if (err != 0)

return err;

/* ignore errors since we can't report them, can we? */

if (_Py_DisplaySourceLine(f, filename, lineno, 4))

PyErr_Clear();

return err;

}

static int

tb_printinternal(PyTracebackObject *tb, PyObject *f, long limit)

{

int err = 0;

long depth = 0;

PyTracebackObject *tb1 = tb;

while (tb1 != NULL) {

depth++;

tb1 = tb1->tb_next;

}

while (tb != NULL && err == 0) {

if (depth <= limit) {

err = tb_displayline(f,

tb->tb_frame->f_code->co_filename,

tb->tb_lineno,

tb->tb_frame->f_code->co_name);

}

depth--;

tb = tb->tb_next;

if (err == 0)

err = PyErr_CheckSignals();

}

return err;

}

#define PyTraceBack_LIMIT 1000

int

PyTraceBack_Print(PyObject *v, PyObject *f)

{

int err;

PyObject *limitv;

long limit = PyTraceBack_LIMIT;

if (v == NULL)

return 0;

if (!PyTraceBack_Check(v)) {

PyErr_BadInternalCall();

return -1;

}

limitv = PySys_GetObject("tracebacklimit");

if (limitv) {

PyObject *exc_type, *exc_value, *exc_tb;

PyErr_Fetch(&exc_type, &exc_value, &exc_tb);

limit = PyLong_AsLong(limitv);

if (limit == -1 && PyErr_Occurred()) {

if (PyErr_ExceptionMatches(PyExc_OverflowError)) {

limit = PyTraceBack_LIMIT;

}

else {

Py_XDECREF(exc_type);

Py_XDECREF(exc_value);

Py_XDECREF(exc_tb);

return 0;

}

}

else if (limit <= 0) {

limit = PyTraceBack_LIMIT;

}

PyErr_Restore(exc_type, exc_value, exc_tb);

}

err = PyFile_WriteString("Traceback (most recent call last):\n", f);

if (!err)

err = tb_printinternal((PyTracebackObject *)v, f, limit);

return err;

}

/* Reverse a string. For example, "abcd" becomes "dcba".

This function is signal safe. */

static void

reverse_string(char *text, const size_t len)

{

char tmp;

size_t i, j;

if (len == 0)

return;

for (i=0, j=len-1; i < j; i++, j--) {

tmp = text[i];

text[i] = text[j];

text[j] = tmp;

}

}

/* Format an integer in range [0; 999999] to decimal,

and write it into the file fd.

This function is signal safe. */

static void

dump_decimal(int fd, int value)

{

char buffer[7];

int len;

if (value < 0 || 999999 < value)

return;

len = 0;

do {

buffer[len] = '0' + (value % 10);

value /= 10;

len++;

} while (value);

reverse_string(buffer, len);

write(fd, buffer, len);

}

/* Format an integer in range [0; 0xffffffff] to hexadecimal of 'width' digits,

and write it into the file fd.

This function is signal safe. */

static void

dump_hexadecimal(int fd, unsigned long value, int width)

{

int len;

char buffer[sizeof(unsigned long) * 2 + 1];

len = 0;

do {

buffer[len] = Py_hexdigits[value & 15];

value >>= 4;

len++;

} while (len < width || value);

reverse_string(buffer, len);

write(fd, buffer, len);

}

/* Write an unicode object into the file fd using ascii+backslashreplace.

This function is signal safe. */

static void

dump_ascii(int fd, PyObject *text)

{

PyASCIIObject *ascii = (PyASCIIObject *)text;

Py_ssize_t i, size;

int truncated;

int kind;

void *data = NULL;

wchar_t *wstr = NULL;

Py_UCS4 ch;

size = ascii->length;

kind = ascii->state.kind;

if (ascii->state.compact) {

if (ascii->state.ascii)

data = ((PyASCIIObject*)text) + 1;

else

data = ((PyCompactUnicodeObject*)text) + 1;

}

else if (kind != PyUnicode_WCHAR_KIND) {

data = ((PyUnicodeObject *)text)->data.any;

if (data == NULL)

return;

}

else {

wstr = ((PyASCIIObject *)text)->wstr;

if (wstr == NULL)

return;

size = ((PyCompactUnicodeObject *)text)->wstr_length;

}

if (MAX_STRING_LENGTH < size) {

size = MAX_STRING_LENGTH;

truncated = 1;

}

else

truncated = 0;

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

if (kind != PyUnicode_WCHAR_KIND)

ch = PyUnicode_READ(kind, data, i);

else

ch = wstr[i];

if (ch < 128) {

char c = (char)ch;

write(fd, &c, 1);

}

else if (ch < 0xff) {

PUTS(fd, "\\x");

dump_hexadecimal(fd, ch, 2);

}

else if (ch < 0xffff) {

PUTS(fd, "\\u");

dump_hexadecimal(fd, ch, 4);

}

else {

PUTS(fd, "\\U");

dump_hexadecimal(fd, ch, 8);

}

}

if (truncated)

PUTS(fd, "...");

}

/* Write a frame into the file fd: "File "xxx", line xxx in xxx".

This function is signal safe. */

static void

dump_frame(int fd, PyFrameObject *frame)

{

PyCodeObject *code;

int lineno;

code = frame->f_code;

PUTS(fd, " File ");

if (code != NULL && code->co_filename != NULL

&& PyUnicode_Check(code->co_filename))

{

write(fd, "\"", 1);

dump_ascii(fd, code->co_filename);

write(fd, "\"", 1);

} else {

PUTS(fd, "???");

}

/* PyFrame_GetLineNumber() was introduced in Python 2.7.0 and 3.2.0 */

lineno = PyCode_Addr2Line(code, frame->f_lasti);

PUTS(fd, ", line ");

dump_decimal(fd, lineno);

PUTS(fd, " in ");

if (code != NULL && code->co_name != NULL

&& PyUnicode_Check(code->co_name))

dump_ascii(fd, code->co_name);

else

PUTS(fd, "???");

write(fd, "\n", 1);

}

static void

dump_traceback(int fd, PyThreadState *tstate, int write_header)

{

PyFrameObject *frame;

unsigned int depth;

if (write_header)

PUTS(fd, "Stack (most recent call first):\n");

frame = _PyThreadState_GetFrame(tstate);

if (frame == NULL)

return;

depth = 0;

while (frame != NULL) {

if (MAX_FRAME_DEPTH <= depth) {

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

break;

}

if (!PyFrame_Check(frame))

break;

dump_frame(fd, frame);

frame = frame->f_back;

depth++;

}

}

void

_Py_DumpTraceback(int fd, PyThreadState *tstate)

{

dump_traceback(fd, tstate, 1);

}

/* Write the thread identifier into the file 'fd': "Current thread 0xHHHH:\" if

is_current is true, "Thread 0xHHHH:\n" otherwise.

This function is signal safe. */

static void

write_thread_id(int fd, PyThreadState *tstate, int is_current)

{

if (is_current)

PUTS(fd, "Current thread 0x");

else

PUTS(fd, "Thread 0x");

dump_hexadecimal(fd, (unsigned long)tstate->thread_id, sizeof(long)*2);

PUTS(fd, " (most recent call first):\n");

}

const char*

_Py_DumpTracebackThreads(int fd, PyInterpreterState *interp,

PyThreadState *current_thread)

{

PyThreadState *tstate;

unsigned int nthreads;

/* Get the current interpreter from the current thread */

tstate = PyInterpreterState_ThreadHead(interp);

if (tstate == NULL)

return "unable to get the thread head state";

/* Dump the traceback of each thread */

tstate = PyInterpreterState_ThreadHead(interp);

nthreads = 0;

do

{

if (nthreads != 0)

write(fd, "\n", 1);

if (nthreads >= MAX_NTHREADS) {

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

break;

}

write_thread_id(fd, tstate, tstate == current_thread);

dump_traceback(fd, tstate, 0);

tstate = PyThreadState_Next(tstate);

nthreads++;

} while (tstate != NULL);

return NULL;

}