pcitool/pcilib/py.c

#include "config.h"

#ifdef HAVE_PYTHON
# include <Python.h>

# if PY_MAJOR_VERSION >= 3
#  include <pthread.h>
# endif /* PY_MAJOR_VERSION >= 3 */
#endif /* HAVE_PYTHON */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <alloca.h>

#include "pci.h"
#include "debug.h"
#include "pcilib.h"
#include "py.h"
#include "error.h"

#ifdef HAVE_PYTHON
# define PCILIB_PYTHON_WRAPPER "pcipywrap"

typedef struct pcilib_script_s pcilib_script_t;

struct pcilib_script_s {
    const char *name;			/**< Script name */
    PyObject *module;			/**< PyModule object, contains script enviroment */	
    UT_hash_handle hh;			/**< hash */
};

struct pcilib_py_s {
    int finalyze; 			/**< Indicates, that we are initialized from wrapper and should not destroy Python resources in destructor */
    PyObject *main_module;		/**< Main interpreter */
    PyObject *pywrap_module;		/**< Pcilib python wrapper */
    PyObject *threading_module;		/**< Threading module */
    PyObject *global_dict;		/**< Dictionary of main interpreter */
    PyObject *pcilib_pywrap;		/**< pcilib wrapper context */
    pcilib_script_t *script_hash;	/**< Hash with loaded scripts */
    
# if PY_MAJOR_VERSION >= 3
    int status;				/**< Indicates if python was initialized successfuly (0) or error have occured */
    pthread_t pth;			/**< Helper thread for Python initialization */
    pthread_cond_t cond;		/**< Condition informing about initialization success and request for clean-up */
    pthread_mutex_t lock;		/**< Condition lock */

//    PyInterpreterState *istate;
//    PyThreadState *tstate;
# endif /* PY_MAJOR_VERSION > 3 */
};
#endif /* HAVE_PYTHON */

void pcilib_log_python_error(const char *file, int line, pcilib_log_flags_t flags, pcilib_log_priority_t prio, const char *msg, ...) {
    va_list va;
    const char *type = NULL;
    const char *val = NULL;

#ifdef HAVE_PYTHON
    PyGILState_STATE gstate;
    PyObject *pytype = NULL;
    PyObject *pyval = NULL;
    PyObject *pystr = NULL;
    PyObject *pytraceback = NULL;


    gstate = PyGILState_Ensure();
    if (PyErr_Occurred()) {
	PyErr_Fetch(&pytype, &pyval, &pytraceback);
	PyErr_NormalizeException(&pytype, &pyval, &pytraceback);
	if (pyval) pystr = PyObject_Str(pyval);

# if PY_MAJOR_VERSION >= 3
	if (pytype) {
	    if (PyUnicode_Check(pytype))
		type = PyUnicode_AsUTF8(pytype);
	    else
		type = PyExceptionClass_Name(pytype);
	}
	if (pystr) {
	    val = PyUnicode_AsUTF8(pystr);
	}
# else /* PY_MAJOR_VERSION >= 3 */
	if (pytype) {
	    if (PyString_Check(pytype))
		type = PyString_AsString(pytype);
	    else
		type = PyExceptionClass_Name(pytype);
	}
	if (pystr) {
	    val = PyString_AsString(pystr);
	}
# endif /*PY_MAJOR_VERSION >= 3*/
    }
    PyGILState_Release(gstate);
#endif /* HAVE_PYTHON */

    va_start(va, msg);
    if (type) {
	char *str;
	size_t len = 32;

	if (msg) len += strlen(msg);
	if (type) len += strlen(type);
	if (val) len += strlen(val);
	    
	str = alloca(len * sizeof(char));
	if (str) {
	    if (msg&&val)
		sprintf(str, "%s <%s: %s>", msg, type, val);
	    else if (msg)
		sprintf(str, "%s <%s>", msg, type);
	    else if (val)
		sprintf(str, "Python error %s: %s", type, val);
	    else
		sprintf(str, "Python error %s", type);
	    
	    pcilib_log_vmessage(file, line, flags, prio, str, va);
	}
    } else  {
	pcilib_log_vmessage(file, line, flags, prio, msg, va);
    }
    va_end(va);

#ifdef HAVE_PYTHON
    if (pystr) Py_DECREF(pystr);
    if (pytype) Py_DECREF(pytype);
    if (pyval) Py_DECREF(pyval);
    if (pytraceback) Py_DECREF(pytraceback);
#endif /* HAVE_PYTHON */
}

#ifdef HAVE_PYTHON
static int pcilib_py_load_default_modules(pcilib_t *ctx) {
    PyGILState_STATE gstate = PyGILState_Ensure();

    ctx->py->main_module = PyImport_AddModule("__parser__");
    if (!ctx->py->main_module) {
	PyGILState_Release(gstate);
	pcilib_python_warning("Error importing python parser");
        return PCILIB_ERROR_FAILED;
    }

    ctx->py->global_dict = PyModule_GetDict(ctx->py->main_module);
    if (!ctx->py->global_dict) {
	PyGILState_Release(gstate);
	pcilib_python_warning("Error locating global python dictionary");
        return PCILIB_ERROR_FAILED;
    }

    ctx->py->pywrap_module = PyImport_ImportModule(PCILIB_PYTHON_WRAPPER);
    if (!ctx->py->pywrap_module) {
	PyGILState_Release(gstate);
	pcilib_python_warning("Error importing pcilib python wrapper");
	return PCILIB_ERROR_FAILED;
    }

    /**
     * We need to load threading module here, otherwise if any of the scripts
     * will use threading, on cleanup Python3 will complain:
     * Exception KeyError: KeyError(140702199305984,) in <module 'threading' from '/usr/lib64/python3.3/threading.py'> ignored
     * The idea to load threading module is inspired by
     * http://stackoverflow.com/questions/8774958/keyerror-in-module-threading-after-a-successful-py-test-run
     */
    ctx->py->threading_module = PyImport_ImportModule("threading");
    if (!ctx->py->threading_module) {
	PyGILState_Release(gstate);
	pcilib_python_warning("Error importing threading python module");
	return PCILIB_ERROR_FAILED;
    }
	
    PyObject *mod_name = PyUnicode_FromString(PCILIB_PYTHON_WRAPPER);
    PyObject *pyctx = PyCapsule_New(ctx, "pcilib", NULL);
    ctx->py->pcilib_pywrap = PyObject_CallMethodObjArgs(ctx->py->pywrap_module, mod_name, pyctx, NULL);
    Py_XDECREF(pyctx);
    Py_XDECREF(mod_name);
	
    if (!ctx->py->pcilib_pywrap) {
	PyGILState_Release(gstate);
	pcilib_python_warning("Error initializing python wrapper");
        return PCILIB_ERROR_FAILED;
    }

    PyGILState_Release(gstate);
    return 0;
}

static void pcilib_py_clean_default_modules(pcilib_t *ctx) {
    PyGILState_STATE gstate;

    gstate = PyGILState_Ensure();

    if (ctx->py->pcilib_pywrap) Py_DECREF(ctx->py->pcilib_pywrap);

    if (ctx->py->threading_module) Py_DECREF(ctx->py->threading_module);
    if (ctx->py->pywrap_module) Py_DECREF(ctx->py->pywrap_module);

	// Crashes Python2
//    if (ctx->py->main_module) Py_DECREF(ctx->py->main_module);

    PyGILState_Release(gstate);
}


# if PY_MAJOR_VERSION >= 3
/**
 * Python3 specially treats the main thread intializing Python. It crashes if
 * the Lock is released and any Python code is executed under the GIL compaling
 * that GIL is not locked. Python3 assumes that the main thread most of the time
 * holds the Lock, only shortly giving it away to other threads and re-obtaining 
 * it hereafter. This is not possible to do with GILs, but instead (probably)
 * PyEval_{Save,Restore}Thread() should be used. On other hand, the other threads
 * are working fine with GILs. This makes things complicated as we need to know
 * if we are running in main thread or not.
 * To simplify matters, during initalization we start a new thread which will
 * performa actual initialization of Python and, hence, act as main thread.
 * We only intialize here. No python code is executed afterwards. So we don't
 * need to care about special locking mechanisms in main thread. Instead all
 * our user threads can use GILs normally. 
 * See more details here:
 * http://stackoverflow.com/questions/24499393/cpython-locking-the-gil-in-the-main-thread
 * http://stackoverflow.com/questions/15470367/pyeval-initthreads-in-python-3-how-when-to-call-it-the-saga-continues-ad-naus
 */
static void *pcilib_py_run_init_thread(void *arg) {
    PyThreadState *state;
    pcilib_t *ctx = (pcilib_t*)arg;
    pcilib_py_t *py = ctx->py;

    Py_Initialize();

    PyEval_InitThreads();

//    state = PyThreadState_Get();
//    py->istate = state->interp;

    py->status = pcilib_py_load_default_modules(ctx);

    state = PyEval_SaveThread();

	// Ensure that main thread waiting for our signal
    pthread_mutex_lock(&(py->lock));

	// Inform the parent thread that initialization is finished
    pthread_cond_signal(&(py->cond));

	// Wait untill cleanup is requested
    pthread_cond_wait(&(py->cond), &(py->lock));
    pthread_mutex_unlock(&(py->lock));

    PyEval_RestoreThread(state);
    pcilib_py_clean_default_modules(ctx);
    Py_Finalize();

    return NULL;
}
# endif /* PY_MAJOR_VERSION < 3 */
#endif /* HAVE_PYTHON */

int pcilib_init_py(pcilib_t *ctx) {
#ifdef HAVE_PYTHON
    int err = 0;

    ctx->py = (pcilib_py_t*)malloc(sizeof(pcilib_py_t));
    if (!ctx->py) return PCILIB_ERROR_MEMORY;
    memset(ctx->py, 0, sizeof(pcilib_py_t));

    if (!Py_IsInitialized()) {
# if PY_MAJOR_VERSION < 3
        Py_Initialize();
    	    // Since python is being initializing from c programm, it needs to initialize threads to work properly with c threads
        PyEval_InitThreads();
        PyEval_ReleaseLock();

	err = pcilib_py_load_default_modules(ctx);
# else /* PY_MAJOR_VERSION < 3 */
	int err = pthread_mutex_init(&(ctx->py->lock), NULL);
	if (err) return PCILIB_ERROR_FAILED;

	err = pthread_cond_init(&(ctx->py->cond), NULL);
	if (err) {
	    pthread_mutex_destroy(&(ctx->py->lock));
	    return PCILIB_ERROR_FAILED;
	}

	err = pthread_mutex_lock(&(ctx->py->lock));
	if (err) {
	    pthread_cond_destroy(&(ctx->py->cond));
	    pthread_mutex_destroy(&(ctx->py->lock));
	    return PCILIB_ERROR_FAILED;
	}

	    // Create initalizer thread and wait until it releases the Lock
        err = pthread_create(&(ctx->py->pth), NULL, pcilib_py_run_init_thread, (void*)ctx);
	if (err) {
	    pthread_mutex_unlock(&(ctx->py->lock));
	    pthread_cond_destroy(&(ctx->py->cond));
	    pthread_mutex_destroy(&(ctx->py->lock));
	    return PCILIB_ERROR_FAILED;
	}

    	    // Wait until initialized and keep the lock afterwards until free executed
	pthread_cond_wait(&(ctx->py->cond), &(ctx->py->lock));
	err = ctx->py->status;

//	ctx->py->tstate =  PyThreadState_New(ctx->py->istate);
# endif /* PY_MAJOR_VERSION < 3 */
	ctx->py->finalyze = 1;
    } else {
	err = pcilib_py_load_default_modules(ctx);
    }

    if (err) {
	pcilib_free_py(ctx);
	return err;
    }
#endif /* HAVE_PYTHON */

    return 0;
}

void pcilib_free_py(pcilib_t *ctx) {
#ifdef HAVE_PYTHON
    if (ctx->py) {
	PyGILState_STATE gstate;

	gstate = PyGILState_Ensure();
	if (ctx->py->script_hash) {
	    pcilib_script_t *script, *script_tmp;

	    HASH_ITER(hh, ctx->py->script_hash, script, script_tmp) {
		Py_DECREF(script->module);
		HASH_DEL(ctx->py->script_hash, script);
		free(script);
	    }
	    ctx->py->script_hash = NULL;
	}
	PyGILState_Release(gstate);

#if PY_MAJOR_VERSION < 3
	pcilib_py_clean_default_modules(ctx);
#endif /* PY_MAJOR_VERSION < 3 */

	if (ctx->py->finalyze) {
#if PY_MAJOR_VERSION < 3
	    Py_Finalize();
#else /* PY_MAJOR_VERSION < 3 */
//	    PyThreadState_Delete(ctx->py->tstate);

		// singal python init thread to stop and wait it to finish
	    pthread_cond_signal(&(ctx->py->cond));
	    pthread_mutex_unlock(&(ctx->py->lock));
	    pthread_join(ctx->py->pth, NULL);

		// destroy synchronization primitives
	    pthread_cond_destroy(&(ctx->py->cond));
	    pthread_mutex_destroy(&(ctx->py->lock));
#endif /* PY_MAJOR_VERSION < 3 */
	}
        free(ctx->py);
        ctx->py = NULL;
    }
#endif /* HAVE_PYTHON */
}

int pcilib_py_add_script_dir(pcilib_t *ctx, const char *dir) {
#ifdef HAVE_PYTHON
    int err = 0;
    PyObject *pypath, *pynewdir;
    PyObject *pydict, *pystr, *pyret = NULL;
    char *script_dir;

    if (!ctx->py) return 0;

    const char *model_dir = getenv("PCILIB_MODEL_DIR");
    if (!model_dir) model_dir = PCILIB_MODEL_DIR;

    if (!dir) dir = ctx->model;

    if (*dir == '/') {
	script_dir = (char*)dir;
    } else {
	script_dir = alloca(strlen(model_dir) + strlen(dir) + 2);
	if (!script_dir) return PCILIB_ERROR_MEMORY;
	sprintf(script_dir, "%s/%s", model_dir, dir);
    }

    PyGILState_STATE gstate = PyGILState_Ensure();

    pypath = PySys_GetObject("path");
    if (!pypath) {
	PyGILState_Release(gstate);
	pcilib_python_warning("Can't get python path");
	return PCILIB_ERROR_FAILED;
    }

    pynewdir = PyUnicode_FromString(script_dir);
    if (!pynewdir) {
	PyGILState_Release(gstate);
	pcilib_python_warning("Can't create python string");
	return PCILIB_ERROR_MEMORY;
    }

    // Checking if the directory already in the path?
    pydict = PyDict_New();
    if (pydict) {
	pystr = PyUnicode_FromString("cur");
        if (pystr) {
	    PyDict_SetItem(pydict, pystr, pynewdir);
	    Py_DECREF(pystr);
	}

	pystr = PyUnicode_FromString("path");
	if (pystr) {
	    PyDict_SetItem(pydict, pystr, pypath);
	    Py_DECREF(pystr);
	}

	pyret = PyRun_String("cur in path", Py_eval_input, ctx->py->global_dict, pydict);
	Py_DECREF(pydict);
    } 

    if ((pyret == Py_False)&&(PyList_Append(pypath, pynewdir) == -1))
	err = PCILIB_ERROR_FAILED;

    if (pyret) Py_DECREF(pyret);
    Py_DECREF(pynewdir);

    PyGILState_Release(gstate);

    if (err) {
	pcilib_python_warning("Can't add directory (%s) to python path", script_dir);
	return err;
    }
#endif /* HAVE_PYTHON */

    return 0;
}


int pcilib_py_load_script(pcilib_t *ctx, const char *script_name) {
#ifdef HAVE_PYTHON
    PyObject* pymodule;
    pcilib_script_t *module = NULL;
    PyGILState_STATE gstate;

    if (!ctx->py) return 0;

    char *module_name = strdupa(script_name);
    if (!module_name) return PCILIB_ERROR_MEMORY;

    char *py = strrchr(module_name, '.');
    if ((!py)||(strcasecmp(py, ".py"))) {
	pcilib_error("Invalid script name (%s) is specified", script_name);
	return PCILIB_ERROR_INVALID_ARGUMENT;
    }
    *py = 0;

    HASH_FIND_STR(ctx->py->script_hash, script_name, module);
    if (module) return 0;

    gstate = PyGILState_Ensure();
    pymodule = PyImport_ImportModule(module_name);
    if (!pymodule) {
	PyGILState_Release(gstate);
	pcilib_python_error("Error importing script (%s)", script_name);
	return PCILIB_ERROR_FAILED;
    }

    module = (pcilib_script_t*)malloc(sizeof(pcilib_script_t));
    if (!module) {
	Py_DECREF(pymodule);
	PyGILState_Release(gstate);
	return PCILIB_ERROR_MEMORY;
    }

    PyGILState_Release(gstate);

    module->module = pymodule;
    module->name = script_name;
    HASH_ADD_KEYPTR(hh, ctx->py->script_hash, module->name, strlen(module->name), module);
#endif /* HAVE_PYTHON */
    return 0;
}

int pcilib_py_get_transform_script_properties(pcilib_t *ctx, const char *script_name, pcilib_access_mode_t *mode_ret) {
    pcilib_access_mode_t mode = 0;

#ifdef HAVE_PYTHON
    PyObject *dict;
    PyObject *pystr;
    pcilib_script_t *module;
    PyGILState_STATE gstate;

    if (!ctx->py) {
	if (mode_ret) *mode_ret = mode;
	return 0;
    }

    HASH_FIND_STR(ctx->py->script_hash, script_name, module);

    if(!module) {
	pcilib_error("Script (%s) is not loaded yet", script_name);
	return PCILIB_ERROR_NOTFOUND;
    }
    
    gstate = PyGILState_Ensure();
	
    dict = PyModule_GetDict(module->module);
    if (!dict) {
	PyGILState_Release(gstate);
	pcilib_python_error("Error getting dictionary for script (%s)", script_name);
	return PCILIB_ERROR_FAILED;
    }
    
    pystr = PyUnicode_FromString("read_from_register");
    if (pystr) {
	if (PyDict_Contains(dict, pystr)) mode |= PCILIB_ACCESS_R;
	Py_DECREF(pystr);
    }

    pystr = PyUnicode_FromString("write_to_register");
    if (pystr) {
	if (PyDict_Contains(dict, pystr)) mode |= PCILIB_ACCESS_W;
	Py_DECREF(pystr);
    }
    
    PyGILState_Release(gstate);
#endif /* HAVE_PYTHON */

//    pcilib_py_load_default_modules(py->ctx);

    if (mode_ret) *mode_ret = mode;
    return 0;
}

pcilib_py_object *pcilib_get_value_as_pyobject(pcilib_t* ctx, pcilib_value_t *val, int *ret) {
#ifdef HAVE_PYTHON	
    int err = 0;
    PyObject *res = NULL;
    PyGILState_STATE gstate;

    long ival;
    double fval;

    if (!ctx->py) return NULL;

    gstate = PyGILState_Ensure();
    switch(val->type) {
     case PCILIB_TYPE_LONG:
	ival = pcilib_get_value_as_int(ctx, val, &err);
	if (!err) res = (PyObject*)PyLong_FromLong(ival);
	break;
     case PCILIB_TYPE_DOUBLE:
	fval = pcilib_get_value_as_float(ctx, val, &err);
	if (!err) res = (PyObject*)PyFloat_FromDouble(fval);
	break;	
     default:
	PyGILState_Release(gstate);
	pcilib_error("Can't convert pcilib value of type (%lu) to PyObject", val->type);
	if (ret) *ret = PCILIB_ERROR_NOTSUPPORTED;
	return NULL;
    }
    PyGILState_Release(gstate);

    if (err) {
	if (ret) *ret = err;
	return NULL;
    } else if (!res) {
	if (ret) *ret = PCILIB_ERROR_MEMORY;
	return res;
    } 

    if (ret) *ret = 0;
    return res;
#else /* HAVE_PYTHON */
    pcilib_error("Python is not supported");
    return NULL;
#endif /* HAVE_PYTHON */
}

int pcilib_set_value_from_pyobject(pcilib_t* ctx, pcilib_value_t *val, pcilib_py_object *pval) {
#ifdef HAVE_PYTHON
    int err = 0;
    PyObject *pyval = (PyObject*)pval;
    PyGILState_STATE gstate;

    if (!ctx->py) return PCILIB_ERROR_NOTINITIALIZED;

    gstate = PyGILState_Ensure();
    if (PyLong_Check(pyval)) {
        err = pcilib_set_value_from_int(ctx, val, PyLong_AsLong(pyval));
    } else if (PyFloat_Check(pyval)) {
        err = pcilib_set_value_from_float(ctx, val, PyFloat_AsDouble(pyval));
#if PY_MAJOR_VERSION < 3
    } else if (PyInt_Check(pyval)) {
        err = pcilib_set_value_from_int(ctx, val, PyInt_AsLong(pyval));
    } else if (PyString_Check(pyval)) {
        err = pcilib_set_value_from_string(ctx, val, PyString_AsString(pyval));
    } else if (PyUnicode_Check(pyval)) {
        PyObject *buf = PyUnicode_AsASCIIString(pyval);
        if (buf) {
    	    err = pcilib_set_value_from_string(ctx, val, PyString_AsString(buf));
    	    Py_DecRef(buf);
    	} else {
    	    err = PCILIB_ERROR_FAILED;
	}
#else /* PY_MAJOR_VERSION < 3 */
    } else if (PyUnicode_Check(pyval)) {
        err = pcilib_set_value_from_string(ctx, val, PyUnicode_AsUTF8(pyval));
#endif /* PY_MAJOR_VERSION < 3 */
    } else {
        PyGILState_Release(gstate);
        pcilib_error("Can't convert PyObject to polymorphic pcilib value");
	return PCILIB_ERROR_NOTSUPPORTED;
    }
    PyGILState_Release(gstate);

    return err;
#else /* HAVE_PYTHON */
    pcilib_error("Python is not supported");
    return PCILIB_ERROR_NOTSUPPORTED;
#endif /* HAVE_PYTHON */
}

#ifdef HAVE_PYTHON
static char *pcilib_py_parse_string(pcilib_t *ctx, const char *codestr, pcilib_value_t *value) {
    int i;
    int err = 0;
    pcilib_value_t val = {0};
    pcilib_register_value_t regval;

    char save;
    char *reg, *cur;
    size_t offset = 0;

    size_t size;
    char *src;
    char *dst;

    size_t max_repl = 2 + 2 * sizeof(pcilib_value_t);                               // the text representation of largest integer

    if (value) {
        err = pcilib_copy_value(ctx, &val, value);
        if (err) return NULL;

        err = pcilib_convert_value_type(ctx, &val, PCILIB_TYPE_STRING);
        if (err) return NULL;

        if (strlen(val.sval) > max_repl)
            max_repl = strlen(val.sval);
    }

    size = ((max_repl + 1) / 3 + 1) * strlen(codestr);                          // minimum register length is 3 symbols ($a + delimiter space), it is replaces with (max_repl+1) symbols

    src = strdup(codestr);
    dst = (char*)malloc(size);                                                  // allocating maximum required space

    if ((!src)||(!dst)) {
        if (src) free(src);
        if (dst) free(dst);
        pcilib_error("Failed to allocate memory for string formulas");
        return NULL;
    }

    cur = src;
    reg = strchr(src, '$');
    while (reg) {
        strcpy(dst + offset, cur);
        offset += reg - cur;

            // find the end of the register name
        reg++;
        if (*reg == '{') {
            reg++;
            for (i = 0; (reg[i])&&(reg[i] != '}'); i++);
            if (!reg[i]) {
                pcilib_error("Python formula (%s) contains unterminated variable reference", codestr);
                err = PCILIB_ERROR_INVALID_DATA;
                break;
            }
        } else {
            for (i = 0; isalnum(reg[i])||(reg[i] == '_'); i++);
        }
        save = reg[i];
        reg[i] = 0;

            // determine replacement value
        if (!strcasecmp(reg, "value")) {
            if (!value) {
                pcilib_error("Python formula (%s) relies on the value of register, but it is not provided", codestr);
                err = PCILIB_ERROR_INVALID_REQUEST;
                break;
            }

            strcpy(dst + offset, val.sval);
        } else {
            if (*reg == '/') {
                pcilib_value_t val = {0};
                err = pcilib_get_property(ctx, reg, &val);
                if (err) break;
                err = pcilib_convert_value_type(ctx, &val, PCILIB_TYPE_STRING);
                if (err) break;
                sprintf(dst + offset, "%s", val.sval);
            } else {
                err = pcilib_read_register(ctx, NULL, reg, &regval);
                if (err) break;
                sprintf(dst + offset, "0x%lx", regval);
            }
        }

        offset += strlen(dst + offset);
        if (save == '}') i++;
        else reg[i] = save;

            // Advance to the next register if any
        cur = reg + i;
        reg = strchr(cur, '$');
    }

    strcpy(dst + offset, cur);

    free(src);

    if (err) {
        free(dst);
        return NULL;
    }

    return dst;
}
#endif /* HAVE_PYTHON */

int pcilib_py_eval_string(pcilib_t *ctx, const char *codestr, pcilib_value_t *value) {
#ifdef HAVE_PYTHON
    int err;

    PyGILState_STATE gstate;
    char *code;
    PyObject* obj;

    if (!ctx->py) return PCILIB_ERROR_NOTINITIALIZED;

    code = pcilib_py_parse_string(ctx, codestr, value);
    if (!code) {
        pcilib_error("Failed to parse registers in the code: %s", codestr);
        return PCILIB_ERROR_FAILED;
    }

    gstate = PyGILState_Ensure();
    obj = PyRun_String(code, Py_eval_input, ctx->py->global_dict, ctx->py->global_dict);
    PyGILState_Release(gstate);

    if (!obj) {
        pcilib_error("Failed to run the Python code: %s", code);
        free(code);
        return PCILIB_ERROR_FAILED;
    }

    pcilib_debug(VIEWS, "Evaluating a Python string \'%s\' to %lf=\'%s\'", codestr, PyFloat_AsDouble(obj), code);
    err = pcilib_set_value_from_float(ctx, value, PyFloat_AsDouble(obj));

    Py_DECREF(obj);
    free(code);

    return err;
#else /* HAVE_PYTHON */
	pcilib_error("Current build not support python.");
    return PCILIB_ERROR_NOTAVAILABLE;
#endif /* HAVE_PYTHON */
}

int pcilib_py_eval_func(pcilib_t *ctx, const char *script_name, const char *func_name, pcilib_value_t *val) {
#ifdef HAVE_PYTHON
    int err = 0;
    PyObject *pyfunc;
    PyObject *pyval = NULL, *pyret;
    pcilib_script_t *module = NULL;

    if (!ctx->py) return PCILIB_ERROR_NOTINITIALIZED;

    HASH_FIND_STR(ctx->py->script_hash, script_name, module);

    if (!module) {
	pcilib_error("Script (%s) is not loaded", script_name);
	return PCILIB_ERROR_NOTFOUND;
    }

    if (val) {
	pyval = pcilib_get_value_as_pyobject(ctx, val, &err);
	if (err) return err;
    }

    PyGILState_STATE gstate = PyGILState_Ensure();

    pyfunc = PyUnicode_FromString(func_name);
    if (!pyfunc) {
	if (pyval) Py_DECREF(pyval);
	PyGILState_Release(gstate);
	return PCILIB_ERROR_MEMORY;
    }

    pyret = PyObject_CallMethodObjArgs(module->module, pyfunc, ctx->py->pcilib_pywrap, pyval, NULL);

    Py_DECREF(pyfunc);
    Py_DECREF(pyval);
	
    if (!pyret) {
	PyGILState_Release(gstate);
	pcilib_python_error("Error executing function (%s) of python script (%s)", func_name, script_name);
	return PCILIB_ERROR_FAILED;
    }

    if ((val)&&(pyret != Py_None))
	err = pcilib_set_value_from_pyobject(ctx, val, pyret);

    Py_DECREF(pyret);
    PyGILState_Release(gstate);

    return err;
#else /* HAVE_PYTHON */
    pcilib_error("Python is not supported");
    return PCILIB_ERROR_NOTSUPPORTED;
#endif /* HAVE_PYTHON */
}