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cpython/Python/marshal.c

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/* Write Python objects to files and read them back.
This is intended for writing and reading compiled Python code only;
a true persistent storage facility would be much harder, since
it would have to take circular links and sharing into account. */
#include "Python.h"
#include "longintrepr.h"
#include "compile.h"
#include "marshal.h"
/* High water mark to determine when the marshalled object is dangerously deep
* and risks coring the interpreter. When the object stack gets this deep,
* raise an exception instead of continuing.
*/
#define MAX_MARSHAL_STACK_DEPTH 5000
#define TYPE_NULL '0'
#define TYPE_NONE 'N'
#define TYPE_STOPITER 'S'
#define TYPE_ELLIPSIS '.'
#define TYPE_INT 'i'
#define TYPE_INT64 'I'
#define TYPE_FLOAT 'f'
#define TYPE_COMPLEX 'x'
#define TYPE_LONG 'l'
#define TYPE_STRING 's'
#define TYPE_TUPLE '('
#define TYPE_LIST '['
#define TYPE_DICT '{'
#define TYPE_CODE 'c'
#define TYPE_UNICODE 'u'
#define TYPE_UNKNOWN '?'
typedef struct {
FILE *fp;
int error;
int depth;
/* If fp == NULL, the following are valid: */
PyObject *str;
char *ptr;
char *end;
} WFILE;
#define w_byte(c, p) if (((p)->fp)) putc((c), (p)->fp); \
else if ((p)->ptr != (p)->end) *(p)->ptr++ = (c); \
else w_more(c, p)
static void
w_more(int c, WFILE *p)
{
int size, newsize;
if (p->str == NULL)
return; /* An error already occurred */
size = PyString_Size(p->str);
newsize = size + 1024;
if (_PyString_Resize(&p->str, newsize) != 0) {
p->ptr = p->end = NULL;
}
else {
p->ptr = PyString_AS_STRING((PyStringObject *)p->str) + size;
p->end =
PyString_AS_STRING((PyStringObject *)p->str) + newsize;
*p->ptr++ = Py_SAFE_DOWNCAST(c, int, char);
}
}
static void
w_string(char *s, int n, WFILE *p)
{
if (p->fp != NULL) {
fwrite(s, 1, n, p->fp);
}
else {
while (--n >= 0) {
w_byte(*s, p);
s++;
}
}
}
static void
w_short(int x, WFILE *p)
{
w_byte( x & 0xff, p);
w_byte((x>> 8) & 0xff, p);
}
static void
w_long(long x, WFILE *p)
{
w_byte((int)( x & 0xff), p);
w_byte((int)((x>> 8) & 0xff), p);
w_byte((int)((x>>16) & 0xff), p);
w_byte((int)((x>>24) & 0xff), p);
}
#if SIZEOF_LONG > 4
static void
w_long64(long x, WFILE *p)
{
w_long(x, p);
w_long(x>>32, p);
}
#endif
static void
w_object(PyObject *v, WFILE *p)
{
int i, n;
p->depth++;
if (p->depth > MAX_MARSHAL_STACK_DEPTH) {
p->error = 2;
}
else if (v == NULL) {
w_byte(TYPE_NULL, p);
}
else if (v == Py_None) {
w_byte(TYPE_NONE, p);
}
else if (v == PyExc_StopIteration) {
w_byte(TYPE_STOPITER, p);
}
else if (v == Py_Ellipsis) {
w_byte(TYPE_ELLIPSIS, p);
}
else if (PyInt_Check(v)) {
long x = PyInt_AS_LONG((PyIntObject *)v);
#if SIZEOF_LONG > 4
long y = Py_ARITHMETIC_RIGHT_SHIFT(long, x, 31);
if (y && y != -1) {
w_byte(TYPE_INT64, p);
w_long64(x, p);
}
else
#endif
{
w_byte(TYPE_INT, p);
w_long(x, p);
}
}
else if (PyLong_Check(v)) {
PyLongObject *ob = (PyLongObject *)v;
w_byte(TYPE_LONG, p);
n = ob->ob_size;
w_long((long)n, p);
if (n < 0)
n = -n;
for (i = 0; i < n; i++)
w_short(ob->ob_digit[i], p);
}
else if (PyFloat_Check(v)) {
char buf[256]; /* Plenty to format any double */
PyFloat_AsReprString(buf, (PyFloatObject *)v);
n = strlen(buf);
w_byte(TYPE_FLOAT, p);
w_byte(n, p);
w_string(buf, n, p);
}
#ifndef WITHOUT_COMPLEX
else if (PyComplex_Check(v)) {
char buf[256]; /* Plenty to format any double */
PyFloatObject *temp;
w_byte(TYPE_COMPLEX, p);
temp = (PyFloatObject*)PyFloat_FromDouble(
PyComplex_RealAsDouble(v));
PyFloat_AsReprString(buf, temp);
Py_DECREF(temp);
n = strlen(buf);
w_byte(n, p);
w_string(buf, n, p);
temp = (PyFloatObject*)PyFloat_FromDouble(
PyComplex_ImagAsDouble(v));
PyFloat_AsReprString(buf, temp);
Py_DECREF(temp);
n = strlen(buf);
w_byte(n, p);
w_string(buf, n, p);
}
#endif
else if (PyString_Check(v)) {
w_byte(TYPE_STRING, p);
n = PyString_GET_SIZE(v);
w_long((long)n, p);
w_string(PyString_AS_STRING(v), n, p);
}
#ifdef Py_USING_UNICODE
else if (PyUnicode_Check(v)) {
PyObject *utf8;
utf8 = PyUnicode_AsUTF8String(v);
if (utf8 == NULL) {
p->depth--;
p->error = 1;
return;
}
w_byte(TYPE_UNICODE, p);
n = PyString_GET_SIZE(utf8);
w_long((long)n, p);
w_string(PyString_AS_STRING(utf8), n, p);
Py_DECREF(utf8);
}
#endif
else if (PyTuple_Check(v)) {
w_byte(TYPE_TUPLE, p);
n = PyTuple_Size(v);
w_long((long)n, p);
for (i = 0; i < n; i++) {
w_object(PyTuple_GET_ITEM(v, i), p);
}
}
else if (PyList_Check(v)) {
w_byte(TYPE_LIST, p);
n = PyList_GET_SIZE(v);
w_long((long)n, p);
for (i = 0; i < n; i++) {
w_object(PyList_GET_ITEM(v, i), p);
}
}
else if (PyDict_Check(v)) {
int pos;
PyObject *key, *value;
w_byte(TYPE_DICT, p);
/* This one is NULL object terminated! */
pos = 0;
while (PyDict_Next(v, &pos, &key, &value)) {
w_object(key, p);
w_object(value, p);
}
w_object((PyObject *)NULL, p);
}
else if (PyCode_Check(v)) {
PyCodeObject *co = (PyCodeObject *)v;
w_byte(TYPE_CODE, p);
w_short(co->co_argcount, p);
w_short(co->co_nlocals, p);
w_short(co->co_stacksize, p);
w_short(co->co_flags, p);
w_object(co->co_code, p);
w_object(co->co_consts, p);
w_object(co->co_names, p);
w_object(co->co_varnames, p);
w_object(co->co_freevars, p);
w_object(co->co_cellvars, p);
w_object(co->co_filename, p);
w_object(co->co_name, p);
w_short(co->co_firstlineno, p);
w_object(co->co_lnotab, p);
}
else if (PyObject_CheckReadBuffer(v)) {
/* Write unknown buffer-style objects as a string */
char *s;
PyBufferProcs *pb = v->ob_type->tp_as_buffer;
w_byte(TYPE_STRING, p);
n = (*pb->bf_getreadbuffer)(v, 0, (void **)&s);
w_long((long)n, p);
w_string(s, n, p);
}
else {
w_byte(TYPE_UNKNOWN, p);
p->error = 1;
}
p->depth--;
}
void
PyMarshal_WriteLongToFile(long x, FILE *fp)
{
WFILE wf;
wf.fp = fp;
wf.error = 0;
wf.depth = 0;
w_long(x, &wf);
}
void
PyMarshal_WriteObjectToFile(PyObject *x, FILE *fp)
{
WFILE wf;
wf.fp = fp;
wf.error = 0;
wf.depth = 0;
w_object(x, &wf);
}
typedef WFILE RFILE; /* Same struct with different invariants */
#define rs_byte(p) (((p)->ptr != (p)->end) ? (unsigned char)*(p)->ptr++ : EOF)
#define r_byte(p) ((p)->fp ? getc((p)->fp) : rs_byte(p))
static int
r_string(char *s, int n, RFILE *p)
{
if (p->fp != NULL)
return fread(s, 1, n, p->fp);
if (p->end - p->ptr < n)
n = p->end - p->ptr;
memcpy(s, p->ptr, n);
p->ptr += n;
return n;
}
static int
r_short(RFILE *p)
{
register short x;
x = r_byte(p);
x |= r_byte(p) << 8;
/* Sign-extension, in case short greater than 16 bits */
x |= -(x & 0x8000);
return x;
}
static long
r_long(RFILE *p)
{
register long x;
register FILE *fp = p->fp;
if (fp) {
x = getc(fp);
x |= (long)getc(fp) << 8;
x |= (long)getc(fp) << 16;
x |= (long)getc(fp) << 24;
}
else {
x = rs_byte(p);
x |= (long)rs_byte(p) << 8;
x |= (long)rs_byte(p) << 16;
x |= (long)rs_byte(p) << 24;
}
#if SIZEOF_LONG > 4
/* Sign extension for 64-bit machines */
x |= -(x & 0x80000000L);
#endif
return x;
}
/* r_long64 deals with the TYPE_INT64 code. On a machine with
sizeof(long) > 4, it returns a Python int object, else a Python long
object. Note that w_long64 writes out TYPE_INT if 32 bits is enough,
so there's no inefficiency here in returning a PyLong on 32-bit boxes
for everything written via TYPE_INT64 (i.e., if an int is written via
TYPE_INT64, it *needs* more than 32 bits).
*/
static PyObject *
r_long64(RFILE *p)
{
long lo4 = r_long(p);
long hi4 = r_long(p);
#if SIZEOF_LONG > 4
long x = (hi4 << 32) | (lo4 & 0xFFFFFFFFL);
return PyInt_FromLong(x);
#else
unsigned char buf[8];
int one = 1;
int is_little_endian = (int)*(char*)&one;
if (is_little_endian) {
memcpy(buf, &lo4, 4);
memcpy(buf+4, &hi4, 4);
}
else {
memcpy(buf, &hi4, 4);
memcpy(buf+4, &lo4, 4);
}
return _PyLong_FromByteArray(buf, 8, is_little_endian, 1);
#endif
}
static PyObject *
r_object(RFILE *p)
{
PyObject *v, *v2;
long i, n;
int type = r_byte(p);
switch (type) {
case EOF:
PyErr_SetString(PyExc_EOFError,
"EOF read where object expected");
return NULL;
case TYPE_NULL:
return NULL;
case TYPE_NONE:
Py_INCREF(Py_None);
return Py_None;
case TYPE_STOPITER:
Py_INCREF(PyExc_StopIteration);
return PyExc_StopIteration;
case TYPE_ELLIPSIS:
Py_INCREF(Py_Ellipsis);
return Py_Ellipsis;
case TYPE_INT:
return PyInt_FromLong(r_long(p));
case TYPE_INT64:
return r_long64(p);
case TYPE_LONG:
{
int size;
PyLongObject *ob;
n = r_long(p);
size = n<0 ? -n : n;
ob = _PyLong_New(size);
if (ob == NULL)
return NULL;
ob->ob_size = n;
for (i = 0; i < size; i++)
ob->ob_digit[i] = r_short(p);
return (PyObject *)ob;
}
case TYPE_FLOAT:
{
char buf[256];
double dx;
n = r_byte(p);
if (r_string(buf, (int)n, p) != n) {
PyErr_SetString(PyExc_EOFError,
"EOF read where object expected");
return NULL;
}
buf[n] = '\0';
PyFPE_START_PROTECT("atof", return 0)
dx = atof(buf);
PyFPE_END_PROTECT(dx)
return PyFloat_FromDouble(dx);
}
#ifndef WITHOUT_COMPLEX
case TYPE_COMPLEX:
{
char buf[256];
Py_complex c;
n = r_byte(p);
if (r_string(buf, (int)n, p) != n) {
PyErr_SetString(PyExc_EOFError,
"EOF read where object expected");
return NULL;
}
buf[n] = '\0';
PyFPE_START_PROTECT("atof", return 0)
c.real = atof(buf);
PyFPE_END_PROTECT(c)
n = r_byte(p);
if (r_string(buf, (int)n, p) != n) {
PyErr_SetString(PyExc_EOFError,
"EOF read where object expected");
return NULL;
}
buf[n] = '\0';
PyFPE_START_PROTECT("atof", return 0)
c.imag = atof(buf);
PyFPE_END_PROTECT(c)
return PyComplex_FromCComplex(c);
}
#endif
case TYPE_STRING:
n = r_long(p);
if (n < 0) {
PyErr_SetString(PyExc_ValueError, "bad marshal data");
return NULL;
}
v = PyString_FromStringAndSize((char *)NULL, n);
if (v != NULL) {
if (r_string(PyString_AS_STRING(v), (int)n, p) != n) {
Py_DECREF(v);
v = NULL;
PyErr_SetString(PyExc_EOFError,
"EOF read where object expected");
}
}
return v;
#ifdef Py_USING_UNICODE
case TYPE_UNICODE:
{
char *buffer;
n = r_long(p);
if (n < 0) {
PyErr_SetString(PyExc_ValueError, "bad marshal data");
return NULL;
}
buffer = PyMem_NEW(char, n);
if (buffer == NULL)
return PyErr_NoMemory();
if (r_string(buffer, (int)n, p) != n) {
PyMem_DEL(buffer);
PyErr_SetString(PyExc_EOFError,
"EOF read where object expected");
return NULL;
}
v = PyUnicode_DecodeUTF8(buffer, n, NULL);
PyMem_DEL(buffer);
return v;
}
#endif
case TYPE_TUPLE:
n = r_long(p);
if (n < 0) {
PyErr_SetString(PyExc_ValueError, "bad marshal data");
return NULL;
}
v = PyTuple_New((int)n);
if (v == NULL)
return v;
for (i = 0; i < n; i++) {
v2 = r_object(p);
if ( v2 == NULL ) {
Py_DECREF(v);
v = NULL;
break;
}
PyTuple_SET_ITEM(v, (int)i, v2);
}
return v;
case TYPE_LIST:
n = r_long(p);
if (n < 0) {
PyErr_SetString(PyExc_ValueError, "bad marshal data");
return NULL;
}
v = PyList_New((int)n);
if (v == NULL)
return v;
for (i = 0; i < n; i++) {
v2 = r_object(p);
if ( v2 == NULL ) {
Py_DECREF(v);
v = NULL;
break;
}
PyList_SetItem(v, (int)i, v2);
}
return v;
case TYPE_DICT:
v = PyDict_New();
if (v == NULL)
return NULL;
for (;;) {
PyObject *key, *val;
key = r_object(p);
if (key == NULL)
break; /* XXX Assume TYPE_NULL, not an error */
val = r_object(p);
if (val != NULL)
PyDict_SetItem(v, key, val);
Py_DECREF(key);
Py_XDECREF(val);
}
return v;
case TYPE_CODE:
if (PyEval_GetRestricted()) {
PyErr_SetString(PyExc_RuntimeError,
"cannot unmarshal code objects in "
"restricted execution mode");
return NULL;
}
else {
int argcount = r_short(p);
int nlocals = r_short(p);
int stacksize = r_short(p);
int flags = r_short(p);
PyObject *code = NULL;
PyObject *consts = NULL;
PyObject *names = NULL;
PyObject *varnames = NULL;
PyObject *freevars = NULL;
PyObject *cellvars = NULL;
PyObject *filename = NULL;
PyObject *name = NULL;
int firstlineno = 0;
PyObject *lnotab = NULL;
code = r_object(p);
if (code) consts = r_object(p);
if (consts) names = r_object(p);
if (names) varnames = r_object(p);
if (varnames) freevars = r_object(p);
if (freevars) cellvars = r_object(p);
if (cellvars) filename = r_object(p);
if (filename) name = r_object(p);
if (name) {
firstlineno = r_short(p);
lnotab = r_object(p);
}
if (!PyErr_Occurred()) {
v = (PyObject *) PyCode_New(
argcount, nlocals, stacksize, flags,
code, consts, names, varnames,
freevars, cellvars, filename, name,
firstlineno, lnotab);
}
else
v = NULL;
Py_XDECREF(code);
Py_XDECREF(consts);
Py_XDECREF(names);
Py_XDECREF(varnames);
Py_XDECREF(freevars);
Py_XDECREF(cellvars);
Py_XDECREF(filename);
Py_XDECREF(name);
Py_XDECREF(lnotab);
}
return v;
default:
/* Bogus data got written, which isn't ideal.
This will let you keep working and recover. */
PyErr_SetString(PyExc_ValueError, "bad marshal data");
return NULL;
}
}
int
PyMarshal_ReadShortFromFile(FILE *fp)
{
RFILE rf;
rf.fp = fp;
return r_short(&rf);
}
long
PyMarshal_ReadLongFromFile(FILE *fp)
{
RFILE rf;
rf.fp = fp;
return r_long(&rf);
}
#ifdef HAVE_FSTAT
/* Return size of file in bytes; < 0 if unknown. */
static off_t
getfilesize(FILE *fp)
{
struct stat st;
if (fstat(fileno(fp), &st) != 0)
return -1;
else
return st.st_size;
}
#endif
/* If we can get the size of the file up-front, and it's reasonably small,
* read it in one gulp and delegate to ...FromString() instead. Much quicker
* than reading a byte at a time from file; speeds .pyc imports.
* CAUTION: since this may read the entire remainder of the file, don't
* call it unless you know you're done with the file.
*/
PyObject *
PyMarshal_ReadLastObjectFromFile(FILE *fp)
{
/* 75% of 2.1's .pyc files can exploit SMALL_FILE_LIMIT.
* REASONABLE_FILE_LIMIT is by defn something big enough for Tkinter.pyc.
*/
#define SMALL_FILE_LIMIT (1L << 14)
#define REASONABLE_FILE_LIMIT (1L << 18)
#ifdef HAVE_FSTAT
off_t filesize;
#endif
if (PyErr_Occurred()) {
fprintf(stderr, "XXX rd_object called with exception set\n");
return NULL;
}
#ifdef HAVE_FSTAT
filesize = getfilesize(fp);
if (filesize > 0) {
char buf[SMALL_FILE_LIMIT];
char* pBuf = NULL;
if (filesize <= SMALL_FILE_LIMIT)
pBuf = buf;
else if (filesize <= REASONABLE_FILE_LIMIT)
pBuf = (char *)PyMem_MALLOC(filesize);
if (pBuf != NULL) {
PyObject* v;
size_t n = fread(pBuf, 1, filesize, fp);
v = PyMarshal_ReadObjectFromString(pBuf, n);
if (pBuf != buf)
PyMem_FREE(pBuf);
return v;
}
}
#endif
/* We don't have fstat, or we do but the file is larger than
* REASONABLE_FILE_LIMIT or malloc failed -- read a byte at a time.
*/
return PyMarshal_ReadObjectFromFile(fp);
#undef SMALL_FILE_LIMIT
#undef REASONABLE_FILE_LIMIT
}
PyObject *
PyMarshal_ReadObjectFromFile(FILE *fp)
{
RFILE rf;
if (PyErr_Occurred()) {
fprintf(stderr, "XXX rd_object called with exception set\n");
return NULL;
}
rf.fp = fp;
return r_object(&rf);
}
PyObject *
PyMarshal_ReadObjectFromString(char *str, int len)
{
RFILE rf;
if (PyErr_Occurred()) {
fprintf(stderr, "XXX rds_object called with exception set\n");
return NULL;
}
rf.fp = NULL;
rf.str = NULL;
rf.ptr = str;
rf.end = str + len;
return r_object(&rf);
}
PyObject *
PyMarshal_WriteObjectToString(PyObject *x) /* wrs_object() */
{
WFILE wf;
wf.fp = NULL;
wf.str = PyString_FromStringAndSize((char *)NULL, 50);
if (wf.str == NULL)
return NULL;
wf.ptr = PyString_AS_STRING((PyStringObject *)wf.str);
wf.end = wf.ptr + PyString_Size(wf.str);
wf.error = 0;
wf.depth = 0;
w_object(x, &wf);
if (wf.str != NULL)
_PyString_Resize(&wf.str,
(int) (wf.ptr -
PyString_AS_STRING((PyStringObject *)wf.str)));
if (wf.error) {
Py_XDECREF(wf.str);
PyErr_SetString(PyExc_ValueError,
(wf.error==1)?"unmarshallable object"
:"object too deeply nested to marshal");
return NULL;
}
return wf.str;
}
/* And an interface for Python programs... */
static PyObject *
marshal_dump(PyObject *self, PyObject *args)
{
WFILE wf;
PyObject *x;
PyObject *f;
if (!PyArg_ParseTuple(args, "OO:dump", &x, &f))
return NULL;
if (!PyFile_Check(f)) {
PyErr_SetString(PyExc_TypeError,
"marshal.dump() 2nd arg must be file");
return NULL;
}
wf.fp = PyFile_AsFile(f);
wf.str = NULL;
wf.ptr = wf.end = NULL;
wf.error = 0;
wf.depth = 0;
w_object(x, &wf);
if (wf.error) {
PyErr_SetString(PyExc_ValueError,
(wf.error==1)?"unmarshallable object"
:"object too deeply nested to marshal");
return NULL;
}
Py_INCREF(Py_None);
return Py_None;
}
static PyObject *
marshal_load(PyObject *self, PyObject *args)
{
RFILE rf;
PyObject *f;
PyObject *v;
if (!PyArg_ParseTuple(args, "O:load", &f))
return NULL;
if (!PyFile_Check(f)) {
PyErr_SetString(PyExc_TypeError,
"marshal.load() arg must be file");
return NULL;
}
rf.fp = PyFile_AsFile(f);
rf.str = NULL;
rf.ptr = rf.end = NULL;
PyErr_Clear();
v = r_object(&rf);
if (PyErr_Occurred()) {
Py_XDECREF(v);
v = NULL;
}
return v;
}
static PyObject *
marshal_dumps(PyObject *self, PyObject *args)
{
PyObject *x;
if (!PyArg_ParseTuple(args, "O:dumps", &x))
return NULL;
return PyMarshal_WriteObjectToString(x);
}
static PyObject *
marshal_loads(PyObject *self, PyObject *args)
{
RFILE rf;
PyObject *v;
char *s;
int n;
if (!PyArg_ParseTuple(args, "s#:loads", &s, &n))
return NULL;
rf.fp = NULL;
rf.str = args;
rf.ptr = s;
rf.end = s + n;
PyErr_Clear();
v = r_object(&rf);
if (PyErr_Occurred()) {
Py_XDECREF(v);
v = NULL;
}
return v;
}
static PyMethodDef marshal_methods[] = {
{"dump", marshal_dump, METH_VARARGS},
{"load", marshal_load, METH_VARARGS},
{"dumps", marshal_dumps, METH_VARARGS},
{"loads", marshal_loads, METH_VARARGS},
{NULL, NULL} /* sentinel */
};
void
PyMarshal_Init(void)
{
(void) Py_InitModule("marshal", marshal_methods);
}
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