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cpython/Python/errors.c

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/* Error handling */
#include "Python.h"
#ifndef __STDC__
#ifndef MS_WINDOWS
extern char *strerror(int);
#endif
#endif
#ifdef MS_WINDOWS
#include <windows.h>
#include <winbase.h>
#endif
#include <ctype.h>
#ifdef __cplusplus
extern "C" {
#endif
void
PyErr_Restore(PyObject *type, PyObject *value, PyObject *traceback)
{
PyThreadState *tstate = PyThreadState_GET();
PyObject *oldtype, *oldvalue, *oldtraceback;
if (traceback != NULL && !PyTraceBack_Check(traceback)) {
/* XXX Should never happen -- fatal error instead? */
/* Well, it could be None. */
Py_DECREF(traceback);
traceback = NULL;
}
/* Save these in locals to safeguard against recursive
invocation through Py_XDECREF */
oldtype = tstate->curexc_type;
oldvalue = tstate->curexc_value;
oldtraceback = tstate->curexc_traceback;
tstate->curexc_type = type;
tstate->curexc_value = value;
tstate->curexc_traceback = traceback;
Py_XDECREF(oldtype);
Py_XDECREF(oldvalue);
Py_XDECREF(oldtraceback);
}
void
PyErr_SetObject(PyObject *exception, PyObject *value)
{
PyThreadState *tstate = PyThreadState_GET();
PyObject *tb = NULL;
if (exception != NULL &&
!PyExceptionClass_Check(exception)) {
PyErr_Format(PyExc_SystemError,
"exception %R not a BaseException subclass",
exception);
return;
}
Py_XINCREF(value);
if (tstate->exc_value != NULL && tstate->exc_value != Py_None) {
/* Implicit exception chaining */
if (value == NULL || !PyExceptionInstance_Check(value)) {
/* We must normalize the value right now */
PyObject *args, *fixed_value;
if (value == NULL || value == Py_None)
args = PyTuple_New(0);
else if (PyTuple_Check(value)) {
Py_INCREF(value);
args = value;
}
else
args = PyTuple_Pack(1, value);
fixed_value = args ?
PyEval_CallObject(exception, args) : NULL;
Py_XDECREF(args);
Py_XDECREF(value);
if (fixed_value == NULL)
return;
value = fixed_value;
}
/* Avoid reference cycles through the context chain.
This is O(chain length) but context chains are
usually very short. Sensitive readers may try
to inline the call to PyException_GetContext. */
if (tstate->exc_value != value) {
PyObject *o = tstate->exc_value, *context;
while ((context = PyException_GetContext(o))) {
Py_DECREF(context);
if (context == value) {
PyException_SetContext(o, NULL);
break;
}
o = context;
}
Py_INCREF(tstate->exc_value);
PyException_SetContext(value, tstate->exc_value);
}
}
if (value != NULL && PyExceptionInstance_Check(value))
tb = PyException_GetTraceback(value);
Py_XINCREF(exception);
PyErr_Restore(exception, value, tb);
}
void
PyErr_SetNone(PyObject *exception)
{
PyErr_SetObject(exception, (PyObject *)NULL);
}
void
PyErr_SetString(PyObject *exception, const char *string)
{
PyObject *value = PyUnicode_FromString(string);
PyErr_SetObject(exception, value);
Py_XDECREF(value);
}
PyObject *
PyErr_Occurred(void)
{
PyThreadState *tstate = PyThreadState_GET();
return tstate->curexc_type;
}
int
PyErr_GivenExceptionMatches(PyObject *err, PyObject *exc)
{
if (err == NULL || exc == NULL) {
/* maybe caused by "import exceptions" that failed early on */
return 0;
}
if (PyTuple_Check(exc)) {
Py_ssize_t i, n;
n = PyTuple_Size(exc);
for (i = 0; i < n; i++) {
/* Test recursively */
if (PyErr_GivenExceptionMatches(
err, PyTuple_GET_ITEM(exc, i)))
{
return 1;
}
}
return 0;
}
/* err might be an instance, so check its class. */
if (PyExceptionInstance_Check(err))
err = PyExceptionInstance_Class(err);
if (PyExceptionClass_Check(err) && PyExceptionClass_Check(exc)) {
int res = 0;
PyObject *exception, *value, *tb;
PyErr_Fetch(&exception, &value, &tb);
res = PyObject_IsSubclass(err, exc);
/* This function must not fail, so print the error here */
if (res == -1) {
PyErr_WriteUnraisable(err);
/* issubclass did not succeed */
res = 0;
}
PyErr_Restore(exception, value, tb);
return res;
}
return err == exc;
}
int
PyErr_ExceptionMatches(PyObject *exc)
{
return PyErr_GivenExceptionMatches(PyErr_Occurred(), exc);
}
/* Used in many places to normalize a raised exception, including in
eval_code2(), do_raise(), and PyErr_Print()
XXX: should PyErr_NormalizeException() also call
PyException_SetTraceback() with the resulting value and tb?
*/
void
PyErr_NormalizeException(PyObject **exc, PyObject **val, PyObject **tb)
{
PyObject *type = *exc;
PyObject *value = *val;
PyObject *inclass = NULL;
PyObject *initial_tb = NULL;
PyThreadState *tstate = NULL;
if (type == NULL) {
/* There was no exception, so nothing to do. */
return;
}
/* If PyErr_SetNone() was used, the value will have been actually
set to NULL.
*/
if (!value) {
value = Py_None;
Py_INCREF(value);
}
if (PyExceptionInstance_Check(value))
inclass = PyExceptionInstance_Class(value);
/* Normalize the exception so that if the type is a class, the
value will be an instance.
*/
if (PyExceptionClass_Check(type)) {
/* if the value was not an instance, or is not an instance
whose class is (or is derived from) type, then use the
value as an argument to instantiation of the type
class.
*/
if (!inclass || !PyObject_IsSubclass(inclass, type)) {
PyObject *args, *res;
if (value == Py_None)
args = PyTuple_New(0);
else if (PyTuple_Check(value)) {
Py_INCREF(value);
args = value;
}
else
args = PyTuple_Pack(1, value);
if (args == NULL)
goto finally;
res = PyEval_CallObject(type, args);
Py_DECREF(args);
if (res == NULL)
goto finally;
Py_DECREF(value);
value = res;
}
/* if the class of the instance doesn't exactly match the
class of the type, believe the instance
*/
else if (inclass != type) {
Py_DECREF(type);
type = inclass;
Py_INCREF(type);
}
}
*exc = type;
*val = value;
return;
finally:
Py_DECREF(type);
Py_DECREF(value);
/* If the new exception doesn't set a traceback and the old
exception had a traceback, use the old traceback for the
new exception. It's better than nothing.
*/
initial_tb = *tb;
PyErr_Fetch(exc, val, tb);
if (initial_tb != NULL) {
if (*tb == NULL)
*tb = initial_tb;
else
Py_DECREF(initial_tb);
}
/* normalize recursively */
tstate = PyThreadState_GET();
if (++tstate->recursion_depth > Py_GetRecursionLimit()) {
--tstate->recursion_depth;
PyErr_SetObject(PyExc_RuntimeError, PyExc_RecursionErrorInst);
return;
}
PyErr_NormalizeException(exc, val, tb);
--tstate->recursion_depth;
}
void
PyErr_Fetch(PyObject **p_type, PyObject **p_value, PyObject **p_traceback)
{
PyThreadState *tstate = PyThreadState_GET();
*p_type = tstate->curexc_type;
*p_value = tstate->curexc_value;
*p_traceback = tstate->curexc_traceback;
tstate->curexc_type = NULL;
tstate->curexc_value = NULL;
tstate->curexc_traceback = NULL;
}
void
PyErr_Clear(void)
{
PyErr_Restore(NULL, NULL, NULL);
}
/* Convenience functions to set a type error exception and return 0 */
int
PyErr_BadArgument(void)
{
PyErr_SetString(PyExc_TypeError,
"bad argument type for built-in operation");
return 0;
}
PyObject *
PyErr_NoMemory(void)
{
if (PyErr_ExceptionMatches(PyExc_MemoryError))
/* already current */
return NULL;
/* raise the pre-allocated instance if it still exists */
if (PyExc_MemoryErrorInst)
{
/* Clear the previous traceback, otherwise it will be appended
* to the current one.
*
* The following statement is not likely to raise any error;
* if it does, we simply discard it.
*/
PyException_SetTraceback(PyExc_MemoryErrorInst, Py_None);
PyErr_SetObject(PyExc_MemoryError, PyExc_MemoryErrorInst);
}
else
/* this will probably fail since there's no memory and hee,
hee, we have to instantiate this class
*/
PyErr_SetNone(PyExc_MemoryError);
return NULL;
}
PyObject *
PyErr_SetFromErrnoWithFilenameObject(PyObject *exc, PyObject *filenameObject)
{
PyObject *message;
PyObject *v;
int i = errno;
#ifdef PLAN9
char errbuf[ERRMAX];
#else
#ifndef MS_WINDOWS
char *s;
#else
WCHAR *s_buf = NULL;
#endif /* Unix/Windows */
#endif /* PLAN 9*/
#ifdef EINTR
if (i == EINTR && PyErr_CheckSignals())
return NULL;
#endif
#ifdef PLAN9
rerrstr(errbuf, sizeof errbuf);
message = PyUnicode_DecodeUTF8(errbuf, strlen(errbuf), "ignore");
#else
#ifndef MS_WINDOWS
if (i == 0)
s = "Error"; /* Sometimes errno didn't get set */
else
s = strerror(i);
message = PyUnicode_DecodeUTF8(s, strlen(s), "ignore");
#else
if (i == 0)
message = PyUnicode_FromString("Error"); /* Sometimes errno didn't get set */
else
{
/* Note that the Win32 errors do not lineup with the
errno error. So if the error is in the MSVC error
table, we use it, otherwise we assume it really _is_
a Win32 error code
*/
if (i > 0 && i < _sys_nerr) {
message = PyUnicode_FromString(_sys_errlist[i]);
}
else {
int len = FormatMessageW(
FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL, /* no message source */
i,
MAKELANGID(LANG_NEUTRAL,
SUBLANG_DEFAULT),
/* Default language */
(LPWSTR) &s_buf,
0, /* size not used */
NULL); /* no args */
if (len==0) {
/* Only ever seen this in out-of-mem
situations */
s_buf = NULL;
message = PyUnicode_FromFormat("Windows Error 0x%X", i);
} else {
/* remove trailing cr/lf and dots */
while (len > 0 && (s_buf[len-1] <= L' ' || s_buf[len-1] == L'.'))
s_buf[--len] = L'\0';
message = PyUnicode_FromUnicode(s_buf, len);
}
}
}
#endif /* Unix/Windows */
#endif /* PLAN 9*/
if (message == NULL)
{
#ifdef MS_WINDOWS
LocalFree(s_buf);
#endif
return NULL;
}
if (filenameObject != NULL)
v = Py_BuildValue("(iOO)", i, message, filenameObject);
else
v = Py_BuildValue("(iO)", i, message);
Py_DECREF(message);
if (v != NULL) {
PyErr_SetObject(exc, v);
Py_DECREF(v);
}
#ifdef MS_WINDOWS
LocalFree(s_buf);
#endif
return NULL;
}
PyObject *
PyErr_SetFromErrnoWithFilename(PyObject *exc, const char *filename)
{
PyObject *name = filename ? PyUnicode_FromString(filename) : NULL;
PyObject *result = PyErr_SetFromErrnoWithFilenameObject(exc, name);
Py_XDECREF(name);
return result;
}
#ifdef Py_WIN_WIDE_FILENAMES
PyObject *
PyErr_SetFromErrnoWithUnicodeFilename(PyObject *exc, const Py_UNICODE *filename)
{
PyObject *name = filename ?
PyUnicode_FromUnicode(filename, wcslen(filename)) :
NULL;
PyObject *result = PyErr_SetFromErrnoWithFilenameObject(exc, name);
Py_XDECREF(name);
return result;
}
#endif /* Py_WIN_WIDE_FILENAMES */
PyObject *
PyErr_SetFromErrno(PyObject *exc)
{
return PyErr_SetFromErrnoWithFilenameObject(exc, NULL);
}
#ifdef MS_WINDOWS
/* Windows specific error code handling */
PyObject *PyErr_SetExcFromWindowsErrWithFilenameObject(
PyObject *exc,
int ierr,
PyObject *filenameObject)
{
int len;
WCHAR *s_buf = NULL; /* Free via LocalFree */
PyObject *message;
PyObject *v;
DWORD err = (DWORD)ierr;
if (err==0) err = GetLastError();
len = FormatMessageW(
/* Error API error */
FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL, /* no message source */
err,
MAKELANGID(LANG_NEUTRAL,
SUBLANG_DEFAULT), /* Default language */
(LPWSTR) &s_buf,
0, /* size not used */
NULL); /* no args */
if (len==0) {
/* Only seen this in out of mem situations */
message = PyUnicode_FromFormat("Windows Error 0x%X", err);
s_buf = NULL;
} else {
/* remove trailing cr/lf and dots */
while (len > 0 && (s_buf[len-1] <= L' ' || s_buf[len-1] == L'.'))
s_buf[--len] = L'\0';
message = PyUnicode_FromUnicode(s_buf, len);
}
if (message == NULL)
{
LocalFree(s_buf);
return NULL;
}
if (filenameObject != NULL)
v = Py_BuildValue("(iOO)", err, message, filenameObject);
else
v = Py_BuildValue("(iO)", err, message);
Py_DECREF(message);
if (v != NULL) {
PyErr_SetObject(exc, v);
Py_DECREF(v);
}
LocalFree(s_buf);
return NULL;
}
PyObject *PyErr_SetExcFromWindowsErrWithFilename(
PyObject *exc,
int ierr,
const char *filename)
{
PyObject *name = filename ? PyUnicode_FromString(filename) : NULL;
PyObject *ret = PyErr_SetExcFromWindowsErrWithFilenameObject(exc,
ierr,
name);
Py_XDECREF(name);
return ret;
}
#ifdef Py_WIN_WIDE_FILENAMES
PyObject *PyErr_SetExcFromWindowsErrWithUnicodeFilename(
PyObject *exc,
int ierr,
const Py_UNICODE *filename)
{
PyObject *name = filename ?
PyUnicode_FromUnicode(filename, wcslen(filename)) :
NULL;
PyObject *ret = PyErr_SetExcFromWindowsErrWithFilenameObject(exc,
ierr,
name);
Py_XDECREF(name);
return ret;
}
#endif /* Py_WIN_WIDE_FILENAMES */
PyObject *PyErr_SetExcFromWindowsErr(PyObject *exc, int ierr)
{
return PyErr_SetExcFromWindowsErrWithFilename(exc, ierr, NULL);
}
PyObject *PyErr_SetFromWindowsErr(int ierr)
{
return PyErr_SetExcFromWindowsErrWithFilename(PyExc_WindowsError,
ierr, NULL);
}
PyObject *PyErr_SetFromWindowsErrWithFilename(
int ierr,
const char *filename)
{
PyObject *name = filename ? PyUnicode_FromString(filename) : NULL;
PyObject *result = PyErr_SetExcFromWindowsErrWithFilenameObject(
PyExc_WindowsError,
ierr, name);
Py_XDECREF(name);
return result;
}
#ifdef Py_WIN_WIDE_FILENAMES
PyObject *PyErr_SetFromWindowsErrWithUnicodeFilename(
int ierr,
const Py_UNICODE *filename)
{
PyObject *name = filename ?
PyUnicode_FromUnicode(filename, wcslen(filename)) :
NULL;
PyObject *result = PyErr_SetExcFromWindowsErrWithFilenameObject(
PyExc_WindowsError,
ierr, name);
Py_XDECREF(name);
return result;
}
#endif /* Py_WIN_WIDE_FILENAMES */
#endif /* MS_WINDOWS */
void
_PyErr_BadInternalCall(const char *filename, int lineno)
{
PyErr_Format(PyExc_SystemError,
"%s:%d: bad argument to internal function",
filename, lineno);
}
/* Remove the preprocessor macro for PyErr_BadInternalCall() so that we can
export the entry point for existing object code: */
#undef PyErr_BadInternalCall
void
PyErr_BadInternalCall(void)
{
PyErr_Format(PyExc_SystemError,
"bad argument to internal function");
}
#define PyErr_BadInternalCall() _PyErr_BadInternalCall(__FILE__, __LINE__)
PyObject *
PyErr_Format(PyObject *exception, const char *format, ...)
{
va_list vargs;
PyObject* string;
#ifdef HAVE_STDARG_PROTOTYPES
va_start(vargs, format);
#else
va_start(vargs);
#endif
string = PyUnicode_FromFormatV(format, vargs);
PyErr_SetObject(exception, string);
Py_XDECREF(string);
va_end(vargs);
return NULL;
}
PyObject *
PyErr_NewException(const char *name, PyObject *base, PyObject *dict)
{
const char *dot;
PyObject *modulename = NULL;
PyObject *classname = NULL;
PyObject *mydict = NULL;
PyObject *bases = NULL;
PyObject *result = NULL;
dot = strrchr(name, '.');
if (dot == NULL) {
PyErr_SetString(PyExc_SystemError,
"PyErr_NewException: name must be module.class");
return NULL;
}
if (base == NULL)
base = PyExc_Exception;
if (dict == NULL) {
dict = mydict = PyDict_New();
if (dict == NULL)
goto failure;
}
if (PyDict_GetItemString(dict, "__module__") == NULL) {
modulename = PyUnicode_FromStringAndSize(name,
(Py_ssize_t)(dot-name));
if (modulename == NULL)
goto failure;
if (PyDict_SetItemString(dict, "__module__", modulename) != 0)
goto failure;
}
if (PyTuple_Check(base)) {
bases = base;
/* INCREF as we create a new ref in the else branch */
Py_INCREF(bases);
} else {
bases = PyTuple_Pack(1, base);
if (bases == NULL)
goto failure;
}
/* Create a real new-style class. */
result = PyObject_CallFunction((PyObject *)&PyType_Type, "UOO",
dot+1, bases, dict);
failure:
Py_XDECREF(bases);
Py_XDECREF(mydict);
Py_XDECREF(classname);
Py_XDECREF(modulename);
return result;
}
/* Call when an exception has occurred but there is no way for Python
to handle it. Examples: exception in __del__ or during GC. */
void
PyErr_WriteUnraisable(PyObject *obj)
{
PyObject *f, *t, *v, *tb;
PyErr_Fetch(&t, &v, &tb);
f = PySys_GetObject("stderr");
if (f != NULL && f != Py_None) {
PyFile_WriteString("Exception ", f);
if (t) {
PyObject* moduleName;
char* className;
assert(PyExceptionClass_Check(t));
className = PyExceptionClass_Name(t);
if (className != NULL) {
char *dot = strrchr(className, '.');
if (dot != NULL)
className = dot+1;
}
moduleName = PyObject_GetAttrString(t, "__module__");
if (moduleName == NULL)
PyFile_WriteString("<unknown>", f);
else {
char* modstr = PyUnicode_AsString(moduleName);
if (modstr &&
strcmp(modstr, "builtins") != 0)
{
PyFile_WriteString(modstr, f);
PyFile_WriteString(".", f);
}
}
if (className == NULL)
PyFile_WriteString("<unknown>", f);
else
PyFile_WriteString(className, f);
if (v && v != Py_None) {
PyFile_WriteString(": ", f);
PyFile_WriteObject(v, f, 0);
}
Py_XDECREF(moduleName);
}
PyFile_WriteString(" in ", f);
PyFile_WriteObject(obj, f, 0);
PyFile_WriteString(" ignored\n", f);
PyErr_Clear(); /* Just in case */
}
Py_XDECREF(t);
Py_XDECREF(v);
Py_XDECREF(tb);
}
extern PyObject *PyModule_GetWarningsModule(void);
/* Set file and line information for the current exception.
If the exception is not a SyntaxError, also sets additional attributes
to make printing of exceptions believe it is a syntax error. */
void
PyErr_SyntaxLocation(const char *filename, int lineno)
{
PyObject *exc, *v, *tb, *tmp;
/* add attributes for the line number and filename for the error */
PyErr_Fetch(&exc, &v, &tb);
PyErr_NormalizeException(&exc, &v, &tb);
/* XXX check that it is, indeed, a syntax error. It might not
* be, though. */
tmp = PyLong_FromLong(lineno);
if (tmp == NULL)
PyErr_Clear();
else {
if (PyObject_SetAttrString(v, "lineno", tmp))
PyErr_Clear();
Py_DECREF(tmp);
}
if (filename != NULL) {
tmp = PyUnicode_FromString(filename);
if (tmp == NULL)
PyErr_Clear();
else {
if (PyObject_SetAttrString(v, "filename", tmp))
PyErr_Clear();
Py_DECREF(tmp);
}
tmp = PyErr_ProgramText(filename, lineno);
if (tmp) {
if (PyObject_SetAttrString(v, "text", tmp))
PyErr_Clear();
Py_DECREF(tmp);
}
}
if (PyObject_SetAttrString(v, "offset", Py_None)) {
PyErr_Clear();
}
if (exc != PyExc_SyntaxError) {
if (!PyObject_HasAttrString(v, "msg")) {
tmp = PyObject_Str(v);
if (tmp) {
if (PyObject_SetAttrString(v, "msg", tmp))
PyErr_Clear();
Py_DECREF(tmp);
} else {
PyErr_Clear();
}
}
if (!PyObject_HasAttrString(v, "print_file_and_line")) {
if (PyObject_SetAttrString(v, "print_file_and_line",
Py_None))
PyErr_Clear();
}
}
PyErr_Restore(exc, v, tb);
}
/* Attempt to load the line of text that the exception refers to. If it
fails, it will return NULL but will not set an exception.
XXX The functionality of this function is quite similar to the
functionality in tb_displayline() in traceback.c. */
PyObject *
PyErr_ProgramText(const char *filename, int lineno)
{
FILE *fp;
int i;
char linebuf[1000];
if (filename == NULL || *filename == '\0' || lineno <= 0)
return NULL;
fp = fopen(filename, "r" PY_STDIOTEXTMODE);
if (fp == NULL)
return NULL;
for (i = 0; i < lineno; i++) {
char *pLastChar = &linebuf[sizeof(linebuf) - 2];
do {
*pLastChar = '\0';
if (Py_UniversalNewlineFgets(linebuf, sizeof linebuf,
fp, NULL) == NULL)
break;
/* fgets read *something*; if it didn't get as
far as pLastChar, it must have found a newline
or hit the end of the file; if pLastChar is \n,
it obviously found a newline; else we haven't
yet seen a newline, so must continue */
} while (*pLastChar != '\0' && *pLastChar != '\n');
}
fclose(fp);
if (i == lineno) {
char *p = linebuf;
PyObject *res;
while (*p == ' ' || *p == '\t' || *p == '\014')
p++;
res = PyUnicode_FromString(p);
if (res == NULL)
PyErr_Clear();
return res;
}
return NULL;
}
#ifdef __cplusplus
}
#endif
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