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cpython/Python/marshal.c
Jason Tishler 6bc06eca70 Bug #794140: cygwin builds do not embed 
The embed2.diff patch solves the user's problem by exporting the missing
symbols from the Python core so Python can be embedded in another Cygwin
application (well, at lest vim).
2003-09-04 11:59:50 +00:00

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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_FALSE 'F'
#define TYPE_TRUE 'T'
#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((char)( x & 0xff), p);
w_byte((char)((x>> 8) & 0xff), p);
}
static void
w_long(long x, WFILE *p)
{
w_byte((char)( x & 0xff), p);
w_byte((char)((x>> 8) & 0xff), p);
w_byte((char)((x>>16) & 0xff), p);
w_byte((char)((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 (v == Py_False) {
w_byte(TYPE_FALSE, p);
}
else if (v == Py_True) {
w_byte(TYPE_TRUE, 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_long(co->co_argcount, p);
w_long(co->co_nlocals, p);
w_long(co->co_stacksize, p);
w_long(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_long(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_FALSE:
Py_INCREF(Py_False);
return Py_False;
case TYPE_TRUE:
Py_INCREF(Py_True);
return Py_True;
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_long(p);
int nlocals = r_long(p);
int stacksize = r_long(p);
int flags = r_long(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_long(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 */
};
PyMODINIT_FUNC
PyMarshal_Init(void)
{
(void) Py_InitModule("marshal", marshal_methods);
}
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