kamailio/modules/app_python/python_support.c

/* $Id$
 *
 * Copyright (C) 2009 Sippy Software, Inc., http://www.sippysoft.com
 *
 * This file is part of SIP-Router, a free SIP server.
 *
 * SIP-Router is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version
 *
 * SIP-Router is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
*/

#include <Python.h>
#include <stdio.h>
#include <stdarg.h>

#include "../../dprint.h"
#include "../../mem/mem.h"

#include "python_mod.h"
#include "python_support.h"

void python_handle_exception(const char *fmt, ...)
{
    PyObject *pResult;
    const char *msg;
    char *buf;
    size_t buflen, msglen;
    PyObject *exception, *v, *tb, *args;
    PyObject *line;
    int i;
    char *srcbuf;

    // We don't want to generate traceback when no errors occured
    if (!PyErr_Occurred())
	return;

    if (fmt == NULL)
	srcbuf = NULL;
    else
	srcbuf = make_message(fmt);

    PyErr_Fetch(&exception, &v, &tb);
    PyErr_Clear();
    if (exception == NULL) {
        LM_ERR("python_handle_exception(): Can't get traceback, PyErr_Fetch() has failed.\n");
        return;
    }

    PyErr_NormalizeException(&exception, &v, &tb);
    if (exception == NULL) {
        LM_ERR("python_handle_exception(): Can't get traceback, PyErr_NormalizeException() has failed.\n");
        return;
    }

    args = PyTuple_Pack(3, exception, v, tb ? tb : Py_None);
    Py_XDECREF(exception);
    Py_XDECREF(v);
    Py_XDECREF(tb);
    if (args == NULL) {
        LM_ERR("python_handle_exception(): Can't get traceback, PyTuple_Pack() has failed.\n");
        return;
    }

    pResult = PyObject_CallObject(format_exc_obj, args);
    Py_DECREF(args);
    if (pResult == NULL) {
        LM_ERR("python_handle_exception(): Can't get traceback, traceback.format_exception() has failed.\n");
        return;
    }

    buflen = 1;
    buf = (char *)pkg_realloc(NULL, buflen * sizeof(char *));
    if (!buf)
    {
	LM_ERR("python_handle_exception(): Can't allocate memory (%lu bytes), pkg_realloc() has failed. Not enough memory.\n", (unsigned long)(buflen * sizeof(char *)));
	return;
    }
    memset(buf, 0, sizeof(char *));

    for (i = 0; i < PySequence_Size(pResult); i++) {
        line = PySequence_GetItem(pResult, i);
        if (line == NULL) {
            LM_ERR("python_handle_exception(): Can't get traceback, PySequence_GetItem() has failed.\n");
            Py_DECREF(pResult);
	    if (buf)
		pkg_free(buf);
            return;
        }

        msg = PyString_AsString(line);

        if (msg == NULL) {
            LM_ERR("python_handle_exception(): Can't get traceback, PyString_AsString() has failed.\n");
            Py_DECREF(line);
            Py_DECREF(pResult);
	    if (buf)
		pkg_free(buf);
            return;
        }

	msglen = strlen(msg);
	buflen += ++msglen;

	buf = (char *)pkg_realloc(buf, buflen * sizeof(char *));
	if (!buf)
	{
	    LM_ERR("python_handle_exception(): Can't allocate memory (%lu bytes), pkg_realloc() has failed. Not enough memory.\n", (unsigned long)(buflen * sizeof(char *)));
	    Py_DECREF(line);
	    Py_DECREF(pResult);
	    return;
	}

	strncat(buf, msg, msglen >= buflen ? buflen-1 : msglen);

        Py_DECREF(line);
    }

    if (srcbuf == NULL)
	LM_ERR("Unhandled exception in the Python code:\n%s", buf);
    else
	LM_ERR("%s: Unhandled exception in the Python code:\n%s", srcbuf, buf);

    if (buf)
	pkg_free(buf);

    if (srcbuf)
	pkg_free(srcbuf);

    Py_DECREF(pResult);
}


PyObject *InitTracebackModule()
{
    PyObject *pModule, *pTracebackObject;

    pModule = PyImport_ImportModule("traceback");
    if (pModule == NULL) {
        LM_ERR("InitTracebackModule(): Cannot import module 'traceback'.\n");
        return NULL;
    }

    pTracebackObject = PyObject_GetAttrString(pModule, "format_exception");
    Py_DECREF(pModule);
    if (pTracebackObject == NULL || !PyCallable_Check(pTracebackObject)) {
        LM_ERR("InitTracebackModule(): AttributeError: 'module' object 'traceback' has no attribute 'format_exception'.\n");
        Py_XDECREF(pTracebackObject);
        return NULL;
    }

    return pTracebackObject;
}


char *make_message(const char *fmt, ...)
{
    int n;
    size_t size;
    char *p, *np;
    va_list ap;

    size = 100;     /* Guess we need no more than 100 bytes. */
    p = (char *)pkg_realloc(NULL, size * sizeof(char *));
    if (!p)
    {
	LM_ERR("make_message(): Can't allocate memory (%lu bytes), pkg_malloc() has failed: Not enough memory.\n", (unsigned long)(size * sizeof(char *)));
	return NULL;
    }
    memset(p, 0, size * sizeof(char *));
    
    while (1)
    {
        va_start(ap, fmt);
        n = vsnprintf(p, size, fmt, ap);
        va_end(ap);

        if (n > -1 && n < size)
    	    return p;

        if (n > -1)    /* glibc 2.1 */
    	    size = n+1;
        else           /* glibc 2.0 */
    	    size *= 2;

	np = (char *)pkg_realloc(p, size * sizeof(char *));
        if (!np)
	{
	    LM_ERR("make_message(): Can't allocate memory (%lu bytes), pkg_realloc() has failed: Not enough memory.\n", (unsigned long)size * sizeof(char *));
	    if (p)
    		pkg_free(p);
    	    return NULL;
        }
	else
    	    p = np;
    }

    return NULL;	// shall not happened, but who knows ;)
}

char *get_class_name(PyObject *y)
{
    PyObject *p;
    char *name;

    p = PyObject_GetAttrString(y, "__name__");
    if (p == NULL || p == Py_None)
    {
	Py_XDECREF(p);
	return NULL;
    }

    name = PyString_AsString(p);
    Py_XDECREF(p);

    return name;
}


char *get_instance_class_name(PyObject *y)
{
    PyObject *p, *n;
    char *name;

    n = PyObject_GetAttrString(y, "__class__");
    if (n == NULL || n == Py_None)
    {
	Py_XDECREF(n);
	return NULL;
    }

    p = PyObject_GetAttrString(n, "__name__");
    if (p == NULL || p == Py_None)
    {
	Py_XDECREF(p);
	return NULL;
    }

    name = PyString_AsString(p);
    Py_XDECREF(p);
    Py_XDECREF(n);

    return name;
}