xiaoxiang781216 commented on a change in pull request #3170: URL: https://github.com/apache/incubator-nuttx/pull/3170#discussion_r601535036
########## File path: libs/libc/unistd/lib_getoptvars.c ########## @@ -0,0 +1,170 @@ +/**************************************************************************** + * libs/libc/unistd/lib_getoptvars.c + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. The + * ASF licenses this file to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance with the + * License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT + * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the + * License for the specific language governing permissions and limitations + * under the License. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <unistd.h> +#include <pthread.h> + +#include "unistd.h" +#include "libc.h" + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ + +#define INVALID_KEY CONFIG_TLS_NELEM +#define VALID_KEY(key) ((key) >= 0 && key < CONFIG_TLS_NELEM) + +/* Configuration. Currently no thread-specific data destructors. */ + +#undef HAVE_DESTRUCTOR +#define HAVE_CLEANUP 1 +#define HAVE_TLSVARS 1 + +/* Check if we have some way to avoid a memory leak */ + +#if defined(CONFIG_DISABLE_PTHREAD) || !defined(CONFIG_PTHREAD_CLEANUP) +# undef HAVE_CLEANUP +#endif + +/* Don't use TLS if we cannot avoid the memory leak or if TLS is disabled. + * Furthermore, TLS is not needed in the KERNEL build because it naturally + * supports per-process data. + */ + +#if !defined(HAVE_DESTRUCTOR) && !defined(HAVE_CLEANUP) +# undef HAVE_TLSVARS +#endif + +#ifdef CONFIG_BUILD_KERNEL +# undef HAVE_TLSVARS +#endif + +/**************************************************************************** + * Private Data + ****************************************************************************/ + +#ifdef HAVE_TLSVARS +static pthread_key_t g_getopt_key = (pthread_key_t)INVALID_KEY; +static pthread_mutex_t g_getopt_mutex = PTHREAD_MUTEX_INITIALIZER; + +#else +/* Fallback to avoid memory leak when there is no destructor and no cleanup + * or when there is no TLS. + */ + +FAR struct getopt_s g_getopt_vars = +{ + NULL, + 0, + 1, + '?' +}; +#endif + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +#ifdef HAVE_TLSVARS +void _getopt_destructor(FAR void *getoptvars) +{ + lib_free(getoptvars); +} +#endif + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: getoptvars + * + * Description: + * Returns a pointer to to the thread-specific getopt() data. + * + ****************************************************************************/ + +FAR struct getopt_s *getoptvars(void) +{ +#ifdef HAVE_TLSVARS + FAR struct getopt_s *go; + int ret; + + ret = pthread_mutex_lock(&g_getopt_mutex); + DEBUGASSERT(ret == OK); + UNUSED(ret); + + /* Check if a key has been assigned */ + + if (!VALID_KEY(g_getopt_key)) + { + ret = pthread_key_create(&g_getopt_key, _getopt_destructor); + DEBUGASSERT(ret == OK); + UNUSED(ret); + } + + /* Get the structure of getopt() variables using the key. */ + + go = (FAR struct getopt_s *)pthread_getspecific(g_getopt_key); + if (go == NULL) + { + /* The instance has not yet been created. Allocate getopt() + * it now. + */ + + go = (FAR struct getopt_s *)lib_malloc(sizeof(struct getopt_s)); + DEBUGASSERT(go != NULL); + + /* Initialize the getopt() variables */ + + go->go_optarg = NULL; + go->go_opterr = 0; + go->go_optind = 1; + go->go_optopt = '?'; + + go->go_optptr = NULL; + go->go_binitialized = false; + + /* Save this as the new thread-specific data */ + + ret = pthread_setspecific(g_getopt_key, go); + +#if !defined(HAVE_DESTRUCTOR) && defined(CONFIG_PTHREAD_CLEANUP) + if (ret == OK) + { + /* Free the thread-specific data when the thread exits */ + + pthread_cleanup_push(_getopt_destructor, go); Review comment: from https://pubs.opengroup.org/onlinepubs/7908799/xsh/pthread_cleanup_push.html: pthread_cleanup_pop is desgined to be called before exit the function which call pthread_cleanup_push. The usage in getopt will break the caller: ``` pthread_cleanup_push(my_destructor) getopt pthread_cleanup_pop-->execute _getopt_destructor not my_destructor ``` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
