cpython.git - https://github.com/python/cpython.git

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author	Georg Brandl <georg@python.org>	2012-01-25 21:36:25 (GMT)
committer	Georg Brandl <georg@python.org>	2012-01-25 21:36:25 (GMT)
commit	e9401a0476d7e3e0e7dd89c54190c7f774ca49c1 (patch)
tree	164f8ca81c61791f8a476cf95e1f6b0f0a53a342 /Python/dynload_aix.c
parent	af90a4044571242c81e2f42a1f3c5b277afa9d47 (diff)
download	cpython-e9401a0476d7e3e0e7dd89c54190c7f774ca49c1.zip cpython-e9401a0476d7e3e0e7dd89c54190c7f774ca49c1.tar.gz cpython-e9401a0476d7e3e0e7dd89c54190c7f774ca49c1.tar.bz2

#13852: some small doc fixes.

Diffstat (limited to 'Python/dynload_aix.c')

0 files changed, 0 insertions, 0 deletions

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/* Thread and interpreter state structures and their interfaces */

#include "Python.h"

/* --------------------------------------------------------------------------
CAUTION

Always use PyMem_RawMalloc() and PyMem_RawFree() directly in this file.  A
number of these functions are advertised as safe to call when the GIL isn't
held, and in a debug build Python redirects (e.g.) PyMem_NEW (etc) to Python's
debugging obmalloc functions.  Those aren't thread-safe (they rely on the GIL
to avoid the expense of doing their own locking).
-------------------------------------------------------------------------- */

#ifdef HAVE_DLOPEN
#ifdef HAVE_DLFCN_H
#include <dlfcn.h>
#endif
#ifndef RTLD_LAZY
#define RTLD_LAZY 1
#endif
#endif

#ifdef __cplusplus
extern "C" {
#endif

#ifdef WITH_THREAD
#include "pythread.h"
static PyThread_type_lock head_mutex = NULL; /* Protects interp->tstate_head */
#define HEAD_INIT() (void)(head_mutex || (head_mutex = PyThread_allocate_lock()))
#define HEAD_LOCK() PyThread_acquire_lock(head_mutex, WAIT_LOCK)
#define HEAD_UNLOCK() PyThread_release_lock(head_mutex)

/* The single PyInterpreterState used by this process'
   GILState implementation
*/
static PyInterpreterState *autoInterpreterState = NULL;
static int autoTLSkey = 0;
#else
#define HEAD_INIT() /* Nothing */
#define HEAD_LOCK() /* Nothing */
#define HEAD_UNLOCK() /* Nothing */
#endif

static PyInterpreterState *interp_head = NULL;

/* Assuming the current thread holds the GIL, this is the
   PyThreadState for the current thread. */
_Py_atomic_address _PyThreadState_Current = {NULL};
PyThreadFrameGetter _PyThreadState_GetFrame = NULL;

#ifdef WITH_THREAD
static void _PyGILState_NoteThreadState(PyThreadState* tstate);
#endif


PyInterpreterState *
PyInterpreterState_New(void)
{
    PyInterpreterState *interp = (PyInterpreterState *)
                                 PyMem_RawMalloc(sizeof(PyInterpreterState));

    if (interp != NULL) {
        HEAD_INIT();
#ifdef WITH_THREAD
        if (head_mutex == NULL)
            Py_FatalError("Can't initialize threads for interpreter");
#endif
        interp->modules = NULL;
        interp->modules_by_index = NULL;
        interp->sysdict = NULL;
        interp->builtins = NULL;
        interp->builtins_copy = NULL;
        interp->tstate_head = NULL;
        interp->codec_search_path = NULL;
        interp->codec_search_cache = NULL;
        interp->codec_error_registry = NULL;
        interp->codecs_initialized = 0;
        interp->fscodec_initialized = 0;
        interp->importlib = NULL;
#ifdef HAVE_DLOPEN
#ifdef RTLD_NOW
        interp->dlopenflags = RTLD_NOW;
#else
        interp->dlopenflags = RTLD_LAZY;
#endif
#endif
#ifdef WITH_TSC
        interp->tscdump = 0;
#endif

        HEAD_LOCK();
        interp->next = interp_head;
        interp_head = interp;
        HEAD_UNLOCK();
    }

    return interp;
}


void
PyInterpreterState_Clear(PyInterpreterState *interp)
{
    PyThreadState *p;
    HEAD_LOCK();
    for (p = interp->tstate_head; p != NULL; p = p->next)
        PyThreadState_Clear(p);
    HEAD_UNLOCK();
    Py_CLEAR(interp->codec_search_path);
    Py_CLEAR(interp->codec_search_cache);
    Py_CLEAR(interp->codec_error_registry);
    Py_CLEAR(interp->modules);
    Py_CLEAR(interp->modules_by_index);
    Py_CLEAR(interp->sysdict);
    Py_CLEAR(interp->builtins);
    Py_CLEAR(interp->builtins_copy);
    Py_CLEAR(interp->importlib);
}


static void
zapthreads(PyInterpreterState *interp)
{
    PyThreadState *p;
    /* No need to lock the mutex here because this should only happen
       when the threads are all really dead (XXX famous last words). */
    while ((p = interp->tstate_head) != NULL) {
        PyThreadState_Delete(p);
    }
}


void
PyInterpreterState_Delete(PyInterpreterState *interp)
{
    PyInterpreterState **p;
    zapthreads(interp);
    HEAD_LOCK();
    for (p = &interp_head; ; p = &(*p)->next) {
        if (*p == NULL)
            Py_FatalError(
                "PyInterpreterState_Delete: invalid interp");
        if (*p == interp)
            break;
    }
    if (interp->tstate_head != NULL)
        Py_FatalError("PyInterpreterState_Delete: remaining threads");
    *p = interp->next;
    HEAD_UNLOCK();
    PyMem_RawFree(interp);
#ifdef WITH_THREAD
    if (interp_head == NULL && head_mutex != NULL) {
        PyThread_free_lock(head_mutex);
        head_mutex = NULL;
    }
#endif
}


/* Default implementation for _PyThreadState_GetFrame */
static struct _frame *
threadstate_getframe(PyThreadState *self)
{
    return self->frame;
}

static PyThreadState *
new_threadstate(PyInterpreterState *interp, int init)
{
    PyThreadState *tstate = (PyThreadState *)PyMem_RawMalloc(sizeof(PyThreadState));

    if (_PyThreadState_GetFrame == NULL)
        _PyThreadState_GetFrame = threadstate_getframe;

    if (tstate != NULL) {
        tstate->interp = interp;

        tstate->frame = NULL;
        tstate->recursion_depth = 0;
        tstate->overflowed = 0;
        tstate->recursion_critical = 0;
        tstate->tracing = 0;
        tstate->use_tracing = 0;
        tstate->gilstate_counter = 0;
        tstate->async_exc = NULL;
#ifdef WITH_THREAD
        tstate->thread_id = PyThread_get_thread_ident();
#else
        tstate->thread_id = 0;
#endif

        tstate->dict = NULL;

        tstate->curexc_type = NULL;
        tstate->curexc_value = NULL;
        tstate->curexc_traceback = NULL;

        tstate->exc_type = NULL;
        tstate->exc_value = NULL;
        tstate->exc_traceback = NULL;

        tstate->c_profilefunc = NULL;
        tstate->c_tracefunc = NULL;
        tstate->c_profileobj = NULL;
        tstate->c_traceobj = NULL;

        tstate->trash_delete_nesting = 0;
        tstate->trash_delete_later = NULL;
        tstate->on_delete = NULL;
        tstate->on_delete_data = NULL;

        tstate->coroutine_wrapper = NULL;
        tstate->in_coroutine_wrapper = 0;

        if (init)
            _PyThreadState_Init(tstate);

        HEAD_LOCK();
        tstate->prev = NULL;
        tstate->next = interp->tstate_head;
        if (tstate->next)
            tstate->next->prev = tstate;
        interp->tstate_head = tstate;
        HEAD_UNLOCK();
    }

    return tstate;
}

PyThreadState *
PyThreadState_New(PyInterpreterState *interp)
{
    return new_threadstate(interp, 1);
}

PyThreadState *
_PyThreadState_Prealloc(PyInterpreterState *interp)
{
    return new_threadstate(interp, 0);
}

void
_PyThreadState_Init(PyThreadState *tstate)
{
#ifdef WITH_THREAD
    _PyGILState_NoteThreadState(tstate);
#endif
}

PyObject*
PyState_FindModule(struct PyModuleDef* module)
{
    Py_ssize_t index = module->m_base.m_index;
    PyInterpreterState *state = PyThreadState_GET()->interp;
    PyObject *res;
    if (module->m_slots) {
        return NULL;
    }
    if (index == 0)
        return NULL;
    if (state->modules_by_index == NULL)
        return NULL;
    if (index >= PyList_GET_SIZE(state->modules_by_index))
        return NULL;
    res = PyList_GET_ITEM(state->modules_by_index, index);
    return res==Py_None ? NULL : res;
}

int
_PyState_AddModule(PyObject* module, struct PyModuleDef* def)
{
    PyInterpreterState *state;
    if (def->m_slots) {
        PyErr_SetString(PyExc_SystemError,
                        "PyState_AddModule called on module with slots");
        return -1;
    }
    state = PyThreadState_GET()->interp;
    if (!def)
        return -1;
    if (!state->modules_by_index) {
        state->modules_by_index = PyList_New(0);
        if (!state->modules_by_index)
            return -1;
    }
    while(PyList_GET_SIZE(state->modules_by_index) <= def->m_base.m_index)
        if (PyList_Append(state->modules_by_index, Py_None) < 0)
            return -1;
    Py_INCREF(module);
    return PyList_SetItem(state->modules_by_index,
                          def->m_base.m_index, module);
}

int
PyState_AddModule(PyObject* module, struct PyModuleDef* def)
{
    Py_ssize_t index;
    PyInterpreterState *state = PyThreadState_GET()->interp;
    if (!def) {
        Py_FatalError("PyState_AddModule: Module Definition is NULL");
        return -1;
    }
    index = def->m_base.m_index;
    if (state->modules_by_index) {
        if(PyList_GET_SIZE(state->modules_by_index) >= index) {
            if(module == PyList_GET_ITEM(state->modules_by_index, index)) {
                Py_FatalError("PyState_AddModule: Module already added!");
                return -1;
            }
        }
    }
    return _PyState_AddModule(module, def);
}

int
PyState_RemoveModule(struct PyModuleDef* def)
{
    PyInterpreterState *state;
    Py_ssize_t index = def->m_base.m_index;
    if (def->m_slots) {
        PyErr_SetString(PyExc_SystemError,
                        "PyState_RemoveModule called on module with slots");
        return -1;
    }
    state = PyThreadState_GET()->interp;
    if (index == 0) {
        Py_FatalError("PyState_RemoveModule: Module index invalid.");
        return -1;
    }
    if (state->modules_by_index == NULL) {
        Py_FatalError("PyState_RemoveModule: Interpreters module-list not acessible.");
        return -1;
    }
    if (index > PyList_GET_SIZE(state->modules_by_index)) {
        Py_FatalError("PyState_RemoveModule: Module index out of bounds.");
        return -1;
    }
    return PyList_SetItem(state->modules_by_index, index, Py_None);
}

/* used by import.c:PyImport_Cleanup */
void
_PyState_ClearModules(void)
{
    PyInterpreterState *state = PyThreadState_GET()->interp;
    if (state->modules_by_index) {
        Py_ssize_t i;
        for (i = 0; i < PyList_GET_SIZE(state->modules_by_index); i++) {
            PyObject *m = PyList_GET_ITEM(state->modules_by_index, i);
            if (PyModule_Check(m)) {
                /* cleanup the saved copy of module dicts */
                PyModuleDef *md = PyModule_GetDef(m);
                if (md)
                    Py_CLEAR(md->m_base.m_copy);
            }
        }
        /* Setting modules_by_index to NULL could be dangerous, so we
           clear the list instead. */
        if (PyList_SetSlice(state->modules_by_index,
                            0, PyList_GET_SIZE(state->modules_by_index),
                            NULL))
            PyErr_WriteUnraisable(state->modules_by_index);
    }
}

void
PyThreadState_Clear(PyThreadState *tstate)
{
    if (Py_VerboseFlag && tstate->frame != NULL)
        fprintf(stderr,
          "PyThreadState_Clear: warning: thread still has a frame\n");

    Py_CLEAR(tstate->frame);

    Py_CLEAR(tstate->dict);
    Py_CLEAR(tstate->async_exc);

    Py_CLEAR(tstate->curexc_type);
    Py_CLEAR(tstate->curexc_value);
    Py_CLEAR(tstate->curexc_traceback);

    Py_CLEAR(tstate->exc_type);
    Py_CLEAR(tstate->exc_value);
    Py_CLEAR(tstate->exc_traceback);

    tstate->c_profilefunc = NULL;
    tstate->c_tracefunc = NULL;
    Py_CLEAR(tstate->c_profileobj);
    Py_CLEAR(tstate->c_traceobj);

    Py_CLEAR(tstate->coroutine_wrapper);
}


/* Common code for PyThreadState_Delete() and PyThreadState_DeleteCurrent() */
static void
tstate_delete_common(PyThreadState *tstate)
{
    PyInterpreterState *interp;
    if (tstate == NULL)
        Py_FatalError("PyThreadState_Delete: NULL tstate");
    interp = tstate->interp;
    if (interp == NULL)
        Py_FatalError("PyThreadState_Delete: NULL interp");
    HEAD_LOCK();
    if (tstate->prev)
        tstate->prev->next = tstate->next;
    else
        interp->tstate_head = tstate->next;
    if (tstate->next)
        tstate->next->prev = tstate->prev;
    HEAD_UNLOCK();
    if (tstate->on_delete != NULL) {
        tstate->on_delete(tstate->on_delete_data);
    }
    PyMem_RawFree(tstate);
}


void
PyThreadState_Delete(PyThreadState *tstate)
{
    if (tstate == (PyThreadState*)_Py_atomic_load_relaxed(&_PyThreadState_Current))
        Py_FatalError("PyThreadState_Delete: tstate is still current");
#ifdef WITH_THREAD
    if (autoInterpreterState && PyThread_get_key_value(autoTLSkey) == tstate)
        PyThread_delete_key_value(autoTLSkey);
#endif /* WITH_THREAD */
    tstate_delete_common(tstate);
}


#ifdef WITH_THREAD
void
PyThreadState_DeleteCurrent()
{
    PyThreadState *tstate = (PyThreadState*)_Py_atomic_load_relaxed(
        &_PyThreadState_Current);
    if (tstate == NULL)
        Py_FatalError(
            "PyThreadState_DeleteCurrent: no current tstate");
    _Py_atomic_store_relaxed(&_PyThreadState_Current, NULL);
    if (autoInterpreterState && PyThread_get_key_value(autoTLSkey) == tstate)
        PyThread_delete_key_value(autoTLSkey);
    tstate_delete_common(tstate);
    PyEval_ReleaseLock();
}
#endif /* WITH_THREAD */


/*
 * Delete all thread states except the one passed as argument.
 * Note that, if there is a current thread state, it *must* be the one
 * passed as argument.  Also, this won't touch any other interpreters
 * than the current one, since we don't know which thread state should
 * be kept in those other interpreteres.
 */
void
_PyThreadState_DeleteExcept(PyThreadState *tstate)
{
    PyInterpreterState *interp = tstate->interp;
    PyThreadState *p, *next, *garbage;
    HEAD_LOCK();
    /* Remove all thread states, except tstate, from the linked list of
       thread states.  This will allow calling PyThreadState_Clear()
       without holding the lock. */
    garbage = interp->tstate_head;
    if (garbage == tstate)
        garbage = tstate->next;
    if (tstate->prev)
        tstate->prev->next = tstate->next;
    if (tstate->next)
        tstate->next->prev = tstate->prev;
    tstate->prev = tstate->next = NULL;
    interp->tstate_head = tstate;
    HEAD_UNLOCK();
    /* Clear and deallocate all stale thread states.  Even if this
       executes Python code, we should be safe since it executes
       in the current thread, not one of the stale threads. */
    for (p = garbage; p; p = next) {
        next = p->next;
        PyThreadState_Clear(p);
        PyMem_RawFree(p);
    }
}


PyThreadState *
PyThreadState_Get(void)
{
    PyThreadState *tstate = (PyThreadState*)_Py_atomic_load_relaxed(
        &_PyThreadState_Current);
    if (tstate == NULL)
        Py_FatalError("PyThreadState_Get: no current thread");

    return tstate;
}


PyThreadState *
PyThreadState_Swap(PyThreadState *newts)
{
    PyThreadState *oldts = (PyThreadState*)_Py_atomic_load_relaxed(
        &_PyThreadState_Current);

    _Py_atomic_store_relaxed(&_PyThreadState_Current, newts);
    /* It should not be possible for more than one thread state
       to be used for a thread.  Check this the best we can in debug
       builds.
    */
#if defined(Py_DEBUG) && defined(WITH_THREAD)
    if (newts) {
        /* This can be called from PyEval_RestoreThread(). Similar
           to it, we need to ensure errno doesn't change.
        */
        int err = errno;
        PyThreadState *check = PyGILState_GetThisThreadState();
        if (check && check->interp == newts->interp && check != newts)
            Py_FatalError("Invalid thread state for this thread");
        errno = err;
    }
#endif
    return oldts;
}

/* An extension mechanism to store arbitrary additional per-thread state.
   PyThreadState_GetDict() returns a dictionary that can be used to hold such
   state; the caller should pick a unique key and store its state there.  If
   PyThreadState_GetDict() returns NULL, an exception has *not* been raised
   and the caller should assume no per-thread state is available. */

PyObject *
PyThreadState_GetDict(void)
{
    PyThreadState *tstate = (PyThreadState*)_Py_atomic_load_relaxed(
        &_PyThreadState_Current);
    if (tstate == NULL)
        return NULL;

    if (tstate->dict == NULL) {
        PyObject *d;
        tstate->dict = d = PyDict_New();
        if (d == NULL)
            PyErr_Clear();
    }
    return tstate->dict;
}


/* Asynchronously raise an exception in a thread.
   Requested by Just van Rossum and Alex Martelli.
   To prevent naive misuse, you must write your own extension
   to call this, or use ctypes.  Must be called with the GIL held.
   Returns the number of tstates modified (normally 1, but 0 if `id` didn't
   match any known thread id).  Can be called with exc=NULL to clear an
   existing async exception.  This raises no exceptions. */

int
PyThreadState_SetAsyncExc(long id, PyObject *exc) {
    PyThreadState *tstate = PyThreadState_GET();
    PyInterpreterState *interp = tstate->interp;
    PyThreadState *p;

    /* Although the GIL is held, a few C API functions can be called
     * without the GIL held, and in particular some that create and
     * destroy thread and interpreter states.  Those can mutate the
     * list of thread states we're traversing, so to prevent that we lock
     * head_mutex for the duration.
     */
    HEAD_LOCK();
    for (p = interp->tstate_head; p != NULL; p = p->next) {
        if (p->thread_id == id) {
            /* Tricky:  we need to decref the current value
             * (if any) in p->async_exc, but that can in turn
             * allow arbitrary Python code to run, including
             * perhaps calls to this function.  To prevent
             * deadlock, we need to release head_mutex before
             * the decref.
             */
            PyObject *old_exc = p->async_exc;
            Py_XINCREF(exc);
            p->async_exc = exc;
            HEAD_UNLOCK();
            Py_XDECREF(old_exc);
            _PyEval_SignalAsyncExc();
            return 1;
        }
    }
    HEAD_UNLOCK();
    return 0;
}


/* Routines for advanced debuggers, requested by David Beazley.
   Don't use unless you know what you are doing! */


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