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authorjasone <jasone@FreeBSD.org>2000-06-14 17:17:41 +0000
committerjasone <jasone@FreeBSD.org>2000-06-14 17:17:41 +0000
commit9f479e9f39861a77981b3e6234e796caa25cfe0f (patch)
tree25b4c819ee7794359e6c426e91cd15c2c56a2f49 /lib/libc_r
parentcc22f14b179a55f7686e798febd938bfef76c982 (diff)
downloadFreeBSD-src-9f479e9f39861a77981b3e6234e796caa25cfe0f.zip
FreeBSD-src-9f479e9f39861a77981b3e6234e796caa25cfe0f.tar.gz
pthread_mutex_lock(), pthread_cond_trywait(), and pthread_cond_wait() are
not allowed to return EINTR, but use of pthread_suspend_np() could cause EINTR to be returned. To fix this, restructure pthread_suspend_np() so that it does not interrupt a thread that is waiting on a mutex or condition, and keep enough state around that pthread_resume_np() can fix things up afterwards. Reviewed by: deischen
Diffstat (limited to 'lib/libc_r')
-rw-r--r--lib/libc_r/uthread/pthread_private.h13
-rw-r--r--lib/libc_r/uthread/uthread_cancel.c23
-rw-r--r--lib/libc_r/uthread/uthread_cond.c28
-rw-r--r--lib/libc_r/uthread/uthread_mutex.c52
-rw-r--r--lib/libc_r/uthread/uthread_resume_np.c31
-rw-r--r--lib/libc_r/uthread/uthread_suspend_np.c14
6 files changed, 125 insertions, 36 deletions
diff --git a/lib/libc_r/uthread/pthread_private.h b/lib/libc_r/uthread/pthread_private.h
index a86cfc6..6b48f23 100644
--- a/lib/libc_r/uthread/pthread_private.h
+++ b/lib/libc_r/uthread/pthread_private.h
@@ -350,6 +350,17 @@ struct pthread_attr {
#define PTHREAD_CREATE_SUSPENDED 1
/*
+ * Additional state for a thread suspended with pthread_suspend_np().
+ */
+enum pthread_susp {
+ SUSP_NO, /* Not suspended. */
+ SUSP_YES, /* Suspended. */
+ SUSP_NOWAIT, /* Suspended, was in a mutex or condition queue. */
+ SUSP_MUTEX_WAIT,/* Suspended, still in a mutex queue. */
+ SUSP_COND_WAIT /* Suspended, still in a condition queue. */
+};
+
+/*
* Miscellaneous definitions.
*/
#define PTHREAD_STACK_DEFAULT 65536
@@ -577,7 +588,7 @@ struct pthread {
#define PTHREAD_CANCEL_NEEDED 0x0010
int cancelflags;
- int suspended;
+ enum pthread_susp suspended;
thread_continuation_t continuation;
diff --git a/lib/libc_r/uthread/uthread_cancel.c b/lib/libc_r/uthread/uthread_cancel.c
index 82ddbb8..c6df52e 100644
--- a/lib/libc_r/uthread/uthread_cancel.c
+++ b/lib/libc_r/uthread/uthread_cancel.c
@@ -37,15 +37,6 @@ pthread_cancel(pthread_t pthread)
pthread->cancelflags |= PTHREAD_CANCELLING;
break;
- case PS_SUSPENDED:
- /*
- * This thread isn't in any scheduling
- * queues; just change it's state:
- */
- pthread->cancelflags |= PTHREAD_CANCELLING;
- PTHREAD_SET_STATE(pthread, PS_RUNNING);
- break;
-
case PS_SPINBLOCK:
case PS_FDR_WAIT:
case PS_FDW_WAIT:
@@ -67,6 +58,20 @@ pthread_cancel(pthread_t pthread)
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
break;
+ case PS_SUSPENDED:
+ if (pthread->suspended == SUSP_NO ||
+ pthread->suspended == SUSP_YES ||
+ pthread->suspended == SUSP_NOWAIT) {
+ /*
+ * This thread isn't in any scheduling
+ * queues; just change it's state:
+ */
+ pthread->cancelflags |=
+ PTHREAD_CANCELLING;
+ PTHREAD_SET_STATE(pthread, PS_RUNNING);
+ break;
+ }
+ /* FALLTHROUGH */
case PS_MUTEX_WAIT:
case PS_COND_WAIT:
case PS_FDLR_WAIT:
diff --git a/lib/libc_r/uthread/uthread_cond.c b/lib/libc_r/uthread/uthread_cond.c
index 78ee042..49062be 100644
--- a/lib/libc_r/uthread/uthread_cond.c
+++ b/lib/libc_r/uthread/uthread_cond.c
@@ -285,7 +285,6 @@ pthread_cond_wait(pthread_cond_t * cond, pthread_mutex_t * mutex)
if (interrupted != 0) {
if (_thread_run->continuation != NULL)
_thread_run->continuation((void *) _thread_run);
- rval = EINTR;
}
_thread_leave_cancellation_point();
@@ -455,7 +454,6 @@ pthread_cond_timedwait(pthread_cond_t * cond, pthread_mutex_t * mutex,
if (interrupted != 0) {
if (_thread_run->continuation != NULL)
_thread_run->continuation((void *) _thread_run);
- rval = EINTR;
}
_thread_leave_cancellation_point();
@@ -489,9 +487,18 @@ pthread_cond_signal(pthread_cond_t * cond)
switch ((*cond)->c_type) {
/* Fast condition variable: */
case COND_TYPE_FAST:
- if ((pthread = cond_queue_deq(*cond)) != NULL)
- /* Allow the thread to run: */
- PTHREAD_NEW_STATE(pthread,PS_RUNNING);
+ if ((pthread = cond_queue_deq(*cond)) != NULL) {
+ /*
+ * Unless the thread is currently suspended,
+ * allow it to run. If the thread is suspended,
+ * make a note that the thread isn't in a wait
+ * queue any more.
+ */
+ if (pthread->state != PS_SUSPENDED)
+ PTHREAD_NEW_STATE(pthread,PS_RUNNING);
+ else
+ pthread->suspended = SUSP_NOWAIT;
+ }
/* Check for no more waiters: */
if (TAILQ_FIRST(&(*cond)->c_queue) == NULL)
@@ -546,7 +553,16 @@ pthread_cond_broadcast(pthread_cond_t * cond)
* condition queue:
*/
while ((pthread = cond_queue_deq(*cond)) != NULL) {
- PTHREAD_NEW_STATE(pthread,PS_RUNNING);
+ /*
+ * Unless the thread is currently suspended,
+ * allow it to run. If the thread is suspended,
+ * make a note that the thread isn't in a wait
+ * queue any more.
+ */
+ if (pthread->state != PS_SUSPENDED)
+ PTHREAD_NEW_STATE(pthread,PS_RUNNING);
+ else
+ pthread->suspended = SUSP_NOWAIT;
}
/* There are no more waiting threads: */
diff --git a/lib/libc_r/uthread/uthread_mutex.c b/lib/libc_r/uthread/uthread_mutex.c
index c97c86b..12fdc8e 100644
--- a/lib/libc_r/uthread/uthread_mutex.c
+++ b/lib/libc_r/uthread/uthread_mutex.c
@@ -612,7 +612,6 @@ pthread_mutex_lock(pthread_mutex_t * mutex)
*/
if (_thread_run->interrupted != 0) {
mutex_queue_remove(*mutex, _thread_run);
- ret = EINTR;
}
/* Unlock the mutex structure: */
@@ -777,11 +776,20 @@ mutex_unlock_common(pthread_mutex_t * mutex, int add_reference)
if (((*mutex)->m_owner =
mutex_queue_deq(*mutex)) != NULL) {
/*
- * Allow the new owner of the mutex to
- * run:
+ * Unless the new owner of the mutex is
+ * currently suspended, allow the owner
+ * to run. If the thread is suspended,
+ * make a note that the thread isn't in
+ * a wait queue any more.
*/
- PTHREAD_NEW_STATE((*mutex)->m_owner,
- PS_RUNNING);
+ if (((*mutex)->m_owner->state !=
+ PS_SUSPENDED)) {
+ PTHREAD_NEW_STATE((*mutex)->m_owner,
+ PS_RUNNING);
+ } else {
+ (*mutex)->m_owner->suspended =
+ SUSP_NOWAIT;
+ }
/*
* Add the mutex to the threads list of
@@ -899,11 +907,20 @@ mutex_unlock_common(pthread_mutex_t * mutex, int add_reference)
(*mutex)->m_prio;
/*
- * Allow the new owner of the mutex to
- * run:
+ * Unless the new owner of the mutex is
+ * currently suspended, allow the owner
+ * to run. If the thread is suspended,
+ * make a note that the thread isn't in
+ * a wait queue any more.
*/
- PTHREAD_NEW_STATE((*mutex)->m_owner,
- PS_RUNNING);
+ if (((*mutex)->m_owner->state !=
+ PS_SUSPENDED)) {
+ PTHREAD_NEW_STATE((*mutex)->m_owner,
+ PS_RUNNING);
+ } else {
+ (*mutex)->m_owner->suspended =
+ SUSP_NOWAIT;
+ }
}
}
break;
@@ -1019,11 +1036,20 @@ mutex_unlock_common(pthread_mutex_t * mutex, int add_reference)
(*mutex)->m_prio;
/*
- * Allow the new owner of the mutex to
- * run:
+ * Unless the new owner of the mutex is
+ * currently suspended, allow the owner
+ * to run. If the thread is suspended,
+ * make a note that the thread isn't in
+ * a wait queue any more.
*/
- PTHREAD_NEW_STATE((*mutex)->m_owner,
- PS_RUNNING);
+ if (((*mutex)->m_owner->state !=
+ PS_SUSPENDED)) {
+ PTHREAD_NEW_STATE((*mutex)->m_owner,
+ PS_RUNNING);
+ } else {
+ (*mutex)->m_owner->suspended =
+ SUSP_NOWAIT;
+ }
}
}
break;
diff --git a/lib/libc_r/uthread/uthread_resume_np.c b/lib/libc_r/uthread/uthread_resume_np.c
index fae355a..32b3d05 100644
--- a/lib/libc_r/uthread/uthread_resume_np.c
+++ b/lib/libc_r/uthread/uthread_resume_np.c
@@ -40,12 +40,14 @@
int
pthread_resume_np(pthread_t thread)
{
- int ret;
+ int ret;
+ enum pthread_susp old_suspended;
/* Find the thread in the list of active threads: */
if ((ret = _find_thread(thread)) == 0) {
/* Cancel any pending suspensions: */
- thread->suspended = 0;
+ old_suspended = thread->suspended;
+ thread->suspended = SUSP_NO;
/* Is it currently suspended? */
if (thread->state == PS_SUSPENDED) {
@@ -55,9 +57,28 @@ pthread_resume_np(pthread_t thread)
*/
_thread_kern_sig_defer();
- /* Allow the thread to run. */
- PTHREAD_SET_STATE(thread,PS_RUNNING);
- PTHREAD_PRIOQ_INSERT_TAIL(thread);
+ switch (old_suspended) {
+ case SUSP_MUTEX_WAIT:
+ /* Set the thread's state back. */
+ PTHREAD_SET_STATE(thread,PS_MUTEX_WAIT);
+ break;
+ case SUSP_COND_WAIT:
+ /* Set the thread's state back. */
+ PTHREAD_SET_STATE(thread,PS_COND_WAIT);
+ break;
+ case SUSP_NOWAIT:
+ /* Allow the thread to run. */
+ PTHREAD_SET_STATE(thread,PS_RUNNING);
+ PTHREAD_WAITQ_REMOVE(thread);
+ PTHREAD_PRIOQ_INSERT_TAIL(thread);
+ break;
+ case SUSP_NO:
+ case SUSP_YES:
+ /* Allow the thread to run. */
+ PTHREAD_SET_STATE(thread,PS_RUNNING);
+ PTHREAD_PRIOQ_INSERT_TAIL(thread);
+ break;
+ }
/*
* Undefer and handle pending signals, yielding if
diff --git a/lib/libc_r/uthread/uthread_suspend_np.c b/lib/libc_r/uthread/uthread_suspend_np.c
index 9b08115..083f552 100644
--- a/lib/libc_r/uthread/uthread_suspend_np.c
+++ b/lib/libc_r/uthread/uthread_suspend_np.c
@@ -91,13 +91,23 @@ pthread_suspend_np(pthread_t thread)
break;
case PS_MUTEX_WAIT:
+ /* Mark the thread as suspended and still in a queue. */
+ thread->suspended = SUSP_MUTEX_WAIT;
+
+ PTHREAD_SET_STATE(thread, PS_SUSPENDED);
+ break;
case PS_COND_WAIT:
+ /* Mark the thread as suspended and still in a queue. */
+ thread->suspended = SUSP_COND_WAIT;
+
+ PTHREAD_SET_STATE(thread, PS_SUSPENDED);
+ break;
case PS_FDLR_WAIT:
case PS_FDLW_WAIT:
case PS_FILE_WAIT:
case PS_JOIN:
/* Mark the thread as suspended: */
- thread->suspended = 1;
+ thread->suspended = SUSP_YES;
/*
* Threads in these states may be in queues.
@@ -134,7 +144,7 @@ pthread_suspend_np(pthread_t thread)
static void
finish_suspension(void *arg)
{
- if (_thread_run->suspended != 0)
+ if (_thread_run->suspended != SUSP_NO)
_thread_kern_sched_state(PS_SUSPENDED, __FILE__, __LINE__);
}
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