URL: https://github.com/SSSD/sssd/pull/46 Author: HouzuoGuo Title: #46: sss_client: Defer thread cancellation until completion of nss/pam operations Action: synchronized
To pull the PR as Git branch: git remote add ghsssd https://github.com/SSSD/sssd git fetch ghsssd pull/46/head:pr46 git checkout pr46
From 3eae3802347e244a032624733ae28b720feba1d5 Mon Sep 17 00:00:00 2001 From: Howard Guo <h...@suse.com> Date: Tue, 11 Oct 2016 10:35:13 +0200 Subject: [PATCH] sss_client: Defer thread cancellation until completion of nss/pam operations https://fedorahosted.org/sssd/ticket/3156 The client code is not cancellation-safe, an application which has cancelled an NSS operation will experience subtle bugs, hence thread cancellation is deferred until completion of client operations. --- Makefile.am | 4 --- src/sss_client/common.c | 80 +++++-------------------------------------------- 2 files changed, 7 insertions(+), 77 deletions(-) diff --git a/Makefile.am b/Makefile.am index 1ea8f50..ca561de 100644 --- a/Makefile.am +++ b/Makefile.am @@ -771,10 +771,6 @@ endif CLIENT_LIBS = $(LTLIBINTL) -if HAVE_PTHREAD -CLIENT_LIBS += -lpthread -endif - if WITH_JOURNALD SYSLOG_LIBS = $(JOURNALD_LIBS) endif diff --git a/src/sss_client/common.c b/src/sss_client/common.c index 20106b1..b7a5ed7 100644 --- a/src/sss_client/common.c +++ b/src/sss_client/common.c @@ -1070,86 +1070,28 @@ typedef void (*sss_mutex_init)(void); struct sss_mutex { pthread_mutex_t mtx; - pthread_once_t once; - sss_mutex_init init; + int old_cancel_state; }; -static void sss_nss_mt_init(void); -static void sss_pam_mt_init(void); -static void sss_nss_mc_mt_init(void); +static struct sss_mutex sss_nss_mtx = { .mtx = PTHREAD_MUTEX_INITIALIZER }; -static struct sss_mutex sss_nss_mtx = { .mtx = PTHREAD_MUTEX_INITIALIZER, - .once = PTHREAD_ONCE_INIT, - .init = sss_nss_mt_init }; +static struct sss_mutex sss_pam_mtx = { .mtx = PTHREAD_MUTEX_INITIALIZER }; -static struct sss_mutex sss_pam_mtx = { .mtx = PTHREAD_MUTEX_INITIALIZER, - .once = PTHREAD_ONCE_INIT, - .init = sss_pam_mt_init }; - -static struct sss_mutex sss_nss_mc_mtx = { .mtx = PTHREAD_MUTEX_INITIALIZER, - .once = PTHREAD_ONCE_INIT, - .init = sss_nss_mc_mt_init }; - -/* Wrappers for robust mutex support */ -static int sss_mutexattr_setrobust (pthread_mutexattr_t *attr) -{ -#ifdef HAVE_PTHREAD_MUTEXATTR_SETROBUST - return pthread_mutexattr_setrobust(attr, PTHREAD_MUTEX_ROBUST); -#elif defined(HAVE_PTHREAD_MUTEXATTR_SETROBUST_NP) - return pthread_mutexattr_setrobust_np(attr, PTHREAD_MUTEX_ROBUST_NP); -#else -#warning Robust mutexes are not supported on this platform. - return 0; -#endif -} - -static int sss_mutex_consistent(pthread_mutex_t *mtx) -{ -#ifdef HAVE_PTHREAD_MUTEX_CONSISTENT - return pthread_mutex_consistent(mtx); -#elif defined(HAVE_PTHREAD_MUTEX_CONSISTENT_NP) - return pthread_mutex_consistent_np(mtx); -#else -#warning Robust mutexes are not supported on this platform. - return 0; -#endif -} - -/* Generic mutex init, lock, unlock functions */ -static void sss_mt_init(struct sss_mutex *m) -{ - pthread_mutexattr_t attr; - - if (pthread_mutexattr_init(&attr) != 0) { - return; - } - if (sss_mutexattr_setrobust(&attr) != 0) { - return; - } - - pthread_mutex_init(&m->mtx, &attr); - pthread_mutexattr_destroy(&attr); -} +static struct sss_mutex sss_nss_mc_mtx = { .mtx = PTHREAD_MUTEX_INITIALIZER }; static void sss_mt_lock(struct sss_mutex *m) { - pthread_once(&m->once, m->init); - if (pthread_mutex_lock(&m->mtx) == EOWNERDEAD) { - sss_cli_close_socket(); - sss_mutex_consistent(&m->mtx); - } + pthread_mutex_lock(&m->mtx); + pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &m->old_cancel_state); } static void sss_mt_unlock(struct sss_mutex *m) { + pthread_setcancelstate(m->old_cancel_state, NULL); pthread_mutex_unlock(&m->mtx); } /* NSS mutex wrappers */ -static void sss_nss_mt_init(void) -{ - sss_mt_init(&sss_nss_mtx); -} void sss_nss_lock(void) { sss_mt_lock(&sss_nss_mtx); @@ -1160,10 +1102,6 @@ void sss_nss_unlock(void) } /* NSS mutex wrappers */ -static void sss_pam_mt_init(void) -{ - sss_mt_init(&sss_pam_mtx); -} void sss_pam_lock(void) { sss_mt_lock(&sss_pam_mtx); @@ -1174,10 +1112,6 @@ void sss_pam_unlock(void) } /* NSS mutex wrappers */ -static void sss_nss_mc_mt_init(void) -{ - sss_mt_init(&sss_nss_mc_mtx); -} void sss_nss_mc_lock(void) { sss_mt_lock(&sss_nss_mc_mtx);
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