/* dl module */

#include "Python.h"

#include <dlfcn.h>

#ifdef __VMS
#include <unistd.h>
#endif

#ifndef RTLD_LAZY
#define RTLD_LAZY 1
#endif

typedef void *PyUnivPtr;
typedef struct {
    PyObject_HEAD
    PyUnivPtr *dl_handle;
} dlobject;

static PyTypeObject Dltype;

static PyObject *Dlerror;

static PyObject *
newdlobject(PyUnivPtr *handle)
{
    dlobject *xp;
    xp = PyObject_New(dlobject, &Dltype);
    if (xp == NULL)
        return NULL;
    xp->dl_handle = handle;
    return (PyObject *)xp;
}

static void
dl_dealloc(dlobject *xp)
{
    if (xp->dl_handle != NULL)
        dlclose(xp->dl_handle);
    PyObject_Del(xp);
}

static PyObject *
dl_close(dlobject *xp)
{
    if (xp->dl_handle != NULL) {
        dlclose(xp->dl_handle);
        xp->dl_handle = NULL;
    }
    Py_INCREF(Py_None);
    return Py_None;
}

static PyObject *
dl_sym(dlobject *xp, PyObject *args)
{
    char *name;
    PyUnivPtr *func;
    if (PyString_Check(args)) {
        name = PyString_AS_STRING(args);
    } else {
        PyErr_Format(PyExc_TypeError, "expected string, found %.200s",
                     Py_TYPE(args)->tp_name);
        return NULL;
    }
    func = dlsym(xp->dl_handle, name);
    if (func == NULL) {
        Py_INCREF(Py_None);
        return Py_None;
    }
    return PyInt_FromLong((long)func);
}

static PyObject *
dl_call(dlobject *xp, PyObject *args)
{
    PyObject *name;
    long (*func)(long, long, long, long, long,
                 long, long, long, long, long);
    long alist[10];
    long res;
    Py_ssize_t i;
    Py_ssize_t n = PyTuple_Size(args);
    if (n < 1) {
        PyErr_SetString(PyExc_TypeError, "at least a name is needed");
        return NULL;
    }
    name = PyTuple_GetItem(args, 0);
    if (!PyString_Check(name)) {
        PyErr_SetString(PyExc_TypeError,
                        "function name must be a string");
        return NULL;
    }
    func = (long (*)(long, long, long, long, long,
                     long, long, long, long, long))
      dlsym(xp->dl_handle, PyString_AsString(name));
    if (func == NULL) {
        PyErr_SetString(PyExc_ValueError, dlerror());
        return NULL;
    }
    if (n-1 > 10) {
        PyErr_SetString(PyExc_TypeError,
                        "too many arguments (max 10)");
        return NULL;
    }
    for (i = 1; i < n; i++) {
        PyObject *v = PyTuple_GetItem(args, i);
        if (PyInt_Check(v))
            alist[i-1] = PyInt_AsLong(v);
        else if (PyString_Check(v))
            alist[i-1] = (long)PyString_AsString(v);
        else if (v == Py_None)
            alist[i-1] = (long) ((char *)NULL);
        else {
            PyErr_SetString(PyExc_TypeError,
                       "arguments must be int, string or None");
            return NULL;
        }
    }
    for (; i <= 10; i++)
        alist[i-1] = 0;
    res = (*func)(alist[0], alist[1], alist[2], alist[3], alist[4],
                  alist[5], alist[6], alist[7], alist[8], alist[9]);
    return PyInt_FromLong(res);
}

static PyMethodDef dlobject_methods[] = {
    {"call",            (PyCFunction)dl_call, METH_VARARGS},
    {"sym",             (PyCFunction)dl_sym, METH_O},
    {"close",           (PyCFunction)dl_close, METH_NOARGS},
    {NULL,              NULL}                    /* Sentinel */
};

static PyObject *
dl_getattr(dlobject *xp, char *name)
{
    return Py_FindMethod(dlobject_methods, (PyObject *)xp, name);
}


static PyTypeObject Dltype = {
    PyVarObject_HEAD_INIT(NULL, 0)
    "dl.dl",                    /*tp_name*/
    sizeof(dlobject),           /*tp_basicsize*/
    0,                          /*tp_itemsize*/
    /* methods */
    (destructor)dl_dealloc, /*tp_dealloc*/
    0,                          /*tp_print*/
    (getattrfunc)dl_getattr,/*tp_getattr*/
    0,                          /*tp_setattr*/
    0,                          /*tp_compare*/
    0,                          /*tp_repr*/
    0,                          /*tp_as_number*/
    0,                          /*tp_as_sequence*/
    0,                          /*tp_as_mapping*/
    0,                          /*tp_hash*/
};

static PyObject *
dl_open(PyObject *self, PyObject *args)
{
    char *name;
    int mode;
    PyUnivPtr *handle;
    if (sizeof(int) != sizeof(long) ||
        sizeof(long) != sizeof(char *)) {
        PyErr_SetString(PyExc_SystemError,
 "module dl requires sizeof(int) == sizeof(long) == sizeof(char*)");
                return NULL;
    }

    if (PyArg_ParseTuple(args, "z:open", &name))
        mode = RTLD_LAZY;
    else {
        PyErr_Clear();
        if (!PyArg_ParseTuple(args, "zi:open", &name, &mode))
            return NULL;
#ifndef RTLD_NOW
        if (mode != RTLD_LAZY) {
            PyErr_SetString(PyExc_ValueError, "mode must be 1");
            return NULL;
        }
#endif
    }
    handle = dlopen(name, mode);
    if (handle == NULL) {
        char *errmsg = dlerror();
        if (!errmsg)
            errmsg = "dlopen() error";
        PyErr_SetString(Dlerror, errmsg);
        return NULL;
    }
#ifdef __VMS
    /*   Under OpenVMS dlopen doesn't do any check, just save the name
     * for later use, so we have to check if the file is readable,
     * the name can be a logical or a file from SYS$SHARE.
     */
    if (access(name, R_OK)) {
        char fname[strlen(name) + 20];
        strcpy(fname, "SYS$SHARE:");
        strcat(fname, name);
        strcat(fname, ".EXE");
        if (access(fname, R_OK)) {
            dlclose(handle);
            PyErr_SetString(Dlerror,
                "File not found or protection violation");
            return NULL;
        }
    }
#endif
    return newdlobject(handle);
}

static PyMethodDef dl_methods[] = {
    {"open",            dl_open, METH_VARARGS},
    {NULL,              NULL}           /* sentinel */
};

/* From socketmodule.c
 * Convenience routine to export an integer value.
 *
 * Errors are silently ignored, for better or for worse...
 */
static void
insint(PyObject *d, char *name, int value)
{
    PyObject *v = PyInt_FromLong((long) value);
    if (!v || PyDict_SetItemString(d, name, v))
        PyErr_Clear();

    Py_XDECREF(v);
}

PyMODINIT_FUNC
initdl(void)
{
    PyObject *m, *d, *x;

    if (PyErr_WarnPy3k("the dl module has been removed in "
                        "Python 3.0; use the ctypes module instead", 2) < 0)
    return;

    /* Initialize object type */
    Py_TYPE(&Dltype) = &PyType_Type;

    /* Create the module and add the functions */
    m = Py_InitModule("dl", dl_methods);
    if (m == NULL)
        return;

    /* Add some symbolic constants to the module */
    d = PyModule_GetDict(m);
    Dlerror = x = PyErr_NewException("dl.error", NULL, NULL);
    PyDict_SetItemString(d, "error", x);
    x = PyInt_FromLong((long)RTLD_LAZY);
    PyDict_SetItemString(d, "RTLD_LAZY", x);
#define INSINT(X)    insint(d,#X,X)
#ifdef RTLD_NOW
    INSINT(RTLD_NOW);
#endif
#ifdef RTLD_NOLOAD
    INSINT(RTLD_NOLOAD);
#endif
#ifdef RTLD_GLOBAL
    INSINT(RTLD_GLOBAL);
#endif
#ifdef RTLD_LOCAL
    INSINT(RTLD_LOCAL);
#endif
#ifdef RTLD_PARENT
    INSINT(RTLD_PARENT);
#endif
#ifdef RTLD_GROUP
    INSINT(RTLD_GROUP);
#endif
#ifdef RTLD_WORLD
    INSINT(RTLD_WORLD);
#endif
#ifdef RTLD_NODELETE
    INSINT(RTLD_NODELETE);
#endif
}