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| author | Tobias Brunner <tobias@strongswan.org> | 2014-07-17 10:35:42 +0200 |
|---|---|---|
| committer | Tobias Brunner <tobias@strongswan.org> | 2014-09-09 10:56:15 +0200 |
| commit | dbd7f4be31210044e85f70a054d921a7176403fc (patch) | |
| tree | 0513b9f27ecefa2f31e1466938d8956e9b0f5022 | |
| parent | 7e433456fcbfc19f8531258da1daad60b02753bf (diff) | |
| download | strongswan-dbd7f4be31210044e85f70a054d921a7176403fc.tar.bz2 strongswan-dbd7f4be31210044e85f70a054d921a7176403fc.tar.xz | |
mutex: Use atomics to set current thread in recursive mutex
Because this->thread is also read by threads that don't hold the
mutex the previous implementation was problematic (especially since
pthread_t is an opaque type of unknown length).
Fixes #654.
| -rw-r--r-- | src/libstrongswan/threading/mutex.c | 21 |
1 files changed, 12 insertions, 9 deletions
diff --git a/src/libstrongswan/threading/mutex.c b/src/libstrongswan/threading/mutex.c index f86e781c5..10cf04542 100644 --- a/src/libstrongswan/threading/mutex.c +++ b/src/libstrongswan/threading/mutex.c @@ -23,6 +23,7 @@ #include <library.h> #include <utils/debug.h> +#include "thread.h" #include "condvar.h" #include "mutex.h" #include "lock_profiler.h" @@ -70,7 +71,7 @@ struct private_r_mutex_t { /** * thread which currently owns mutex */ - pthread_t thread; + thread_t *thread; /** * times the current thread locked the mutex @@ -125,16 +126,16 @@ METHOD(mutex_t, unlock, void, METHOD(mutex_t, lock_r, void, private_r_mutex_t *this) { - pthread_t self = pthread_self(); + thread_t *self = thread_current(); - if (pthread_equal(this->thread, self)) + if (cas_ptr(&this->thread, self, self)) { this->times++; } else { lock(&this->generic); - this->thread = self; + cas_ptr(&this->thread, NULL, self); this->times = 1; } } @@ -144,7 +145,7 @@ METHOD(mutex_t, unlock_r, void, { if (--this->times == 0) { - memset(&this->thread, 0, sizeof(this->thread)); + cas_ptr(&this->thread, thread_current(), NULL); unlock(&this->generic); } } @@ -220,14 +221,15 @@ METHOD(condvar_t, wait_, void, if (mutex->recursive) { private_r_mutex_t* recursive = (private_r_mutex_t*)mutex; + thread_t *self = thread_current(); u_int times; /* keep track of the number of times this thread locked the mutex */ times = recursive->times; /* mutex owner gets cleared during condvar wait */ - memset(&recursive->thread, 0, sizeof(recursive->thread)); + cas_ptr(&recursive->thread, self, NULL); pthread_cond_wait(&this->condvar, &mutex->mutex); - recursive->thread = pthread_self(); + cas_ptr(&recursive->thread, NULL, self); recursive->times = times; } else @@ -253,13 +255,14 @@ METHOD(condvar_t, timed_wait_abs, bool, if (mutex->recursive) { private_r_mutex_t* recursive = (private_r_mutex_t*)mutex; + thread_t *self = thread_current(); u_int times; times = recursive->times; - memset(&recursive->thread, 0, sizeof(recursive->thread)); + cas_ptr(&recursive->thread, self, NULL); timed_out = pthread_cond_timedwait(&this->condvar, &mutex->mutex, &ts) == ETIMEDOUT; - recursive->thread = pthread_self(); + cas_ptr(&recursive->thread, NULL, self); recursive->times = times; } else |