reading a python file object in c extension crashes python

[travis ray]

Hi,

I have an extension in which a file object is created in python and
passed down to a c extension which attempts to read from it or write
to it.  Writing to the file pointer seems to work okay, but reading
from it results in EBADF and causes python to crash on exit.

I've attached the minimal (I think) c code, python code, build script,
build log, and run log.  Any and all help is greatly appreciated.

Thanks.

System: Win-XP Professional
Compiler: Vc7 (MSVS 2003)
Python: Python 2.4.1
Builder: SCons 0.96.1

#include <Python.h>
#define MAXLEN 128

int 
my_read(char *buffer, int max, FILE *fp)
{   
    int n = 0;
    fprintf (stdout, "[c] pre-read: errno=%d, fp=%x\n", errno, fp);
    n = fread(buffer, 1, max, fp);
    fprintf (stdout, "[c] post-write: errno=%d, fp=%x, count=%d, data='%s'\n", 
errno, fp, n, buffer);
    return n;
}

int 
my_write(const char *buffer, FILE *fp)
{   
    int n = 0;
    fprintf (stdout, "[c] pre-write: errno=%d, fp=%x, data='%s'\n", errno, fp, 
buffer);
    n = fprintf(fp, "%s", buffer);
    fprintf (stdout, "[c] post-write: errno=%d, fp=%x, count=%d\n", errno, fp, 
n);
    return n;
}

static PyObject *
my_module_my_read(PyObject *self, PyObject *args)
{
    char buffer[MAXLEN];
    int  count = 0;
    FILE *fp = NULL;
    PyObject* py_file = NULL;
    
    memset((void*)&(buffer),0,sizeof(char)*MAXLEN);
    
    if (!PyArg_ParseTuple(args, "O", &py_file))
        return NULL;

    if (PyFile_Check(py_file))
    {
        
        /*count = my_read((char*)&(buffer), MAXLEN, PyFile_AsFile(py_file));*/
        count = my_read((char*)&(buffer), MAXLEN, ((PyFileObject 
*)py_file)->f_fp);
        return Py_BuildValue("(is)", count, (char*)buffer);
    }
    return NULL;
}

static PyObject *
my_module_my_write(PyObject *self, PyObject *args)
{
    char buffer[MAXLEN];
    int  count = 0;
    FILE *fp = NULL;
    PyObject* py_file = NULL;
    const char* py_string;
    
    memset((void*)&(buffer),0,sizeof(char)*MAXLEN);

    if (!PyArg_ParseTuple(args, "sO", &py_string, &py_file))
        return NULL;

    if ((PyFile_Check(py_file)) && (py_string != NULL))
    {
        count = my_write(py_string, PyFile_AsFile(py_file));        
        return Py_BuildValue("i", count);
    }
    return NULL;
}

static PyMethodDef MyModuleMethods[] = {
    {"my_read",  my_module_my_read,  METH_VARARGS, "read at most 128 bytes from 
a file"},
    {"my_write", my_module_my_write, METH_VARARGS, "write a string to a file"},
    {NULL,NULL,0,NULL}
};

PyMODINIT_FUNC
initmy_module(void)
{
    PyObject *m;
    m = Py_InitModule("my_module", MyModuleMethods);
}

import my_module

filename = "hello.txt"
fp1 = open(filename, "wb")
print "[py] pre-write: fp=%s" % (fp1)
result1 = my_module.my_write("Hello, World!", fp1)
print "[py] result=", result1
fp1.close()

fp2 = open(filename, "rb")
print "[py] pre-read: fp=%s" % (fp2)
result2 = my_module.my_read(fp2)
print "[py] result=", result2
#fp2.close()     # <- crashes python here (probably because of EBADF)
print "done"
                # <- crashes python here when fp2.close() is commented out

SConstruct
Description: Binary data

build.log
Description: Binary data

run.log
Description: Binary data

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