From: Sven Trenkel Date: Tue, 16 Aug 2016 21:52:38 +0000 (+0000) Subject: python plugin: Fixing possible problems with the GIL. X-Git-Tag: collectd-5.6.0~5^2~1 X-Git-Url: https://git.tokkee.org/?a=commitdiff_plain;h=46a35862cb9ff3caddad1fc01e02141b6e0a9f72;p=collectd.git python plugin: Fixing possible problems with the GIL. If AfterFork is called after threads have been initialized. Also handle SIGTERM while reading from an interactive session slightly more gracefully. --- diff --git a/src/python.c b/src/python.c index 1a7359cd..27a1b25c 100644 --- a/src/python.c +++ b/src/python.c @@ -925,7 +925,17 @@ static PyMethodDef cpy_methods[] = { static int cpy_shutdown(void) { PyObject *ret; - PyEval_RestoreThread(state); + if (!state) { + printf("================================================================\n"); + printf("collectd shutdown while running an interactive session. This will\n"); + printf("probably leave your terminal in a mess.\n"); + printf("Run the command \"reset\" to get it back into a usable state.\n"); + printf("You can press Ctrl+D in the interactive session to\n"); + printf("close collectd and avoid this problem in the future.\n"); + printf("================================================================\n"); + } + + CPY_LOCK_THREADS for (cpy_callback_t *c = cpy_shutdown_callbacks; c; c = c->next) { ret = PyObject_CallFunctionObjArgs(c->callback, c->data, (void *) 0); /* New reference. */ @@ -936,18 +946,23 @@ static int cpy_shutdown(void) { } PyErr_Print(); + Py_BEGIN_ALLOW_THREADS cpy_unregister_list(&cpy_config_callbacks); cpy_unregister_list(&cpy_init_callbacks); cpy_unregister_list(&cpy_shutdown_callbacks); cpy_shutdown_triggered = 1; + Py_END_ALLOW_THREADS - if (!cpy_num_callbacks) + if (!cpy_num_callbacks) { Py_Finalize(); + return 0; + } + CPY_RELEASE_THREADS return 0; } -static void *cpy_interactive(void *data) { +static void *cpy_interactive(void *pipefd) { PyOS_sighandler_t cur_sig; /* Signal handler in a plugin? Bad stuff, but the best way to @@ -972,18 +987,18 @@ static void *cpy_interactive(void *data) { * This will make sure that SIGINT won't kill collectd but * still interrupt syscalls like sleep and pause. */ - PyEval_AcquireThread(state); if (PyImport_ImportModule("readline") == NULL) { /* This interactive session will suck. */ cpy_log_exception("interactive session init"); } cur_sig = PyOS_setsig(SIGINT, python_sigint_handler); - /* We totally forked just now. Everyone saw that, right? */ PyOS_AfterFork(); + PyEval_InitThreads(); + close(*(int *) pipefd); PyRun_InteractiveLoop(stdin, ""); PyOS_setsig(SIGINT, cur_sig); PyErr_Print(); - PyEval_ReleaseThread(state); + state = PyEval_SaveThread(); NOTICE("python: Interactive interpreter exited, stopping collectd ..."); pthread_kill(main_thread, SIGINT); return NULL; @@ -991,6 +1006,8 @@ static void *cpy_interactive(void *data) { static int cpy_init(void) { PyObject *ret; + int pipefd[2]; + char buf; static pthread_t thread; if (!Py_IsInitialized()) { @@ -999,8 +1016,22 @@ static int cpy_init(void) { Py_Finalize(); return 0; } - PyEval_InitThreads(); - /* Now it's finally OK to use python threads. */ + main_thread = pthread_self(); + if (do_interactive) { + if (pipe(pipefd)) { + ERROR("python: Unable to create pipe."); + return 1; + } + if (plugin_thread_create(&thread, NULL, cpy_interactive, pipefd + 1)) { + ERROR("python: Error creating thread for interactive interpreter."); + } + (void)read(pipefd[0], &buf, 1); + (void)close(pipefd[0]); + } else { + PyEval_InitThreads(); + state = PyEval_SaveThread(); + } + CPY_LOCK_THREADS for (cpy_callback_t *c = cpy_init_callbacks; c; c = c->next) { ret = PyObject_CallFunctionObjArgs(c->callback, c->data, (void *) 0); /* New reference. */ if (ret == NULL) @@ -1008,13 +1039,7 @@ static int cpy_init(void) { else Py_DECREF(ret); } - state = PyEval_SaveThread(); - main_thread = pthread_self(); - if (do_interactive) { - if (plugin_thread_create(&thread, NULL, cpy_interactive, NULL)) { - ERROR("python: Error creating thread for interactive interpreter."); - } - } + CPY_RELEASE_THREADS return 0; }