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Re: PATCH: Threads and SIGINT
Tom Tromey wrote:
> 1. The new "jthread" field in _Jv_Thread_t needs a comment.
> 2. Now that we have jthread, we can remove the "object" field in
> struct starter in posix-threads.cc.
Now that I look at it, "jthread" is redundant. I removed it.
Attached is the patch that I checked in.
regards
[ bryce ]
1999-12-22 Bryce McKinlay <bryce@albatross.co.nz>
* java/lang/natObject.cc (notify): Throw message with
IllegalMonitorStateException.
(notifyAll): Ditto.
(wait): Ditto.
* java/lang/Thread.java (isInterrupted): Don't clear
interrupt_flag.
(isInterrupted_): New function, which does clear interrupt_flag.
(interrupt): Use `isInterrupted_'.
* java/lang/natThread.cc (interrupt): Add comment.
(join): Set `prev' in joiner loop.
Change various calls to `isInterrupted' to use `isInterrupted_'.
* posix-threads.cc (_Jv_CondWait): Allways use
pthread_cond_timedwait
on linux. Set result to 0 on an interrupt. Test interrupted
status
of java Thread object directly.
FLAG_INTERRUPTED: removed.
(_Jv_ThreadStart): Throw OutOfMemoryError if pthread_create
fails.
(_Jv_ThreadInterrupt): Don't set FLAG_INTERRUPTED.
(_Jv_InitThreads): Don't block SIGINT.
(_Jv_ThreadWait): Don't configure SIGINT handler.
Index: libjava/java/lang/natThread.cc
===================================================================
RCS file: /cvs/java/libgcj/libjava/java/lang/natThread.cc,v
retrieving revision 1.8
diff -u -r1.8 natThread.cc
--- natThread.cc 1999/11/05 20:59:40 1.8
+++ natThread.cc 1999/12/24 00:48:39
@@ -130,10 +130,13 @@
// another thread to exit.
natThread *nt = (natThread *) data;
_Jv_MutexLock (&nt->interrupt_mutex);
+ // Notify the interrupt condition to interrupt sleep() and join() calls.
_Jv_CondNotify (&nt->interrupt_cond, &nt->interrupt_mutex);
- _Jv_MutexUnlock (&nt->interrupt_mutex);
-
+ // Send a signal to the target thread to interrupt system calls. On Linux,
+ // this will also interrupt the target thread from *any* _Jv_CondWait call,
+ // ie wait(). This behaviour is not portable, however.
_Jv_ThreadInterrupt (nt->thread);
+ _Jv_MutexUnlock (&nt->interrupt_mutex);
}
void
@@ -145,7 +148,7 @@
_Jv_Throw (new IllegalArgumentException);
Thread *current = currentThread ();
- if (current->isInterrupted ())
+ if (current->isInterrupted_ ())
_Jv_Throw (new InterruptedException);
// Update the list of all threads waiting for this thread to exit.
@@ -199,11 +202,12 @@
t->next = 0;
break;
}
+ prev = t;
}
JvAssert (t != NULL);
_Jv_MonitorExit (this);
- if (current->isInterrupted ())
+ if (current->isInterrupted_ ())
_Jv_Throw (new InterruptedException);
}
@@ -240,7 +244,7 @@
++nanos;
Thread *current = currentThread ();
- if (current->isInterrupted ())
+ if (current->isInterrupted_ ())
_Jv_Throw (new InterruptedException);
// We use a condition variable to implement sleeping so that an
@@ -253,7 +257,7 @@
millis, nanos);
}
- if (current->isInterrupted ())
+ if (current->isInterrupted_ ())
_Jv_Throw (new InterruptedException);
}
Index: libjava/java/lang/natObject.cc
===================================================================
RCS file: /cvs/java/libgcj/libjava/java/lang/natObject.cc,v
retrieving revision 1.4
diff -u -r1.4 natObject.cc
--- natObject.cc 1999/11/25 00:36:51 1.4
+++ natObject.cc 1999/12/24 00:48:40
@@ -175,7 +175,8 @@
sync_init ();
_Jv_SyncInfo *si = (_Jv_SyncInfo *) sync_info;
if (_Jv_CondNotify (&si->condition, &si->mutex))
- JvThrow (new IllegalMonitorStateException);
+ JvThrow (new IllegalMonitorStateException(JvNewStringLatin1
+ ("current thread not owner")));
}
void
@@ -185,7 +186,8 @@
sync_init ();
_Jv_SyncInfo *si = (_Jv_SyncInfo *) sync_info;
if (_Jv_CondNotifyAll (&si->condition, &si->mutex))
- JvThrow (new IllegalMonitorStateException);
+ JvThrow (new IllegalMonitorStateException(JvNewStringLatin1
+ ("current thread not owner")));
}
void
@@ -197,7 +199,8 @@
JvThrow (new IllegalArgumentException);
_Jv_SyncInfo *si = (_Jv_SyncInfo *) sync_info;
if (_Jv_CondWait (&si->condition, &si->mutex, timeout, nanos))
- JvThrow (new IllegalMonitorStateException);
+ JvThrow (new IllegalMonitorStateException(JvNewStringLatin1
+ ("current thread not owner")));
if (Thread::interrupted())
JvThrow (new InterruptedException);
}
Index: libjava/posix-threads.cc
===================================================================
RCS file: /cvs/java/libgcj/libjava/posix-threads.cc,v
retrieving revision 1.14
diff -u -r1.14 posix-threads.cc
--- posix-threads.cc 1999/11/30 18:53:15 1.14
+++ posix-threads.cc 1999/12/24 00:48:42
@@ -27,11 +27,14 @@
#include <time.h>
#include <signal.h>
#include <errno.h>
+#include <limits.h>
#include <gcj/cni.h>
#include <jvm.h>
#include <java/lang/Thread.h>
#include <java/lang/System.h>
+#include <java/lang/Long.h>
+#include <java/lang/OutOfMemoryError.h>
// This is used to implement thread startup.
struct starter
@@ -58,7 +61,7 @@
// The signal to use when interrupting a thread.
#ifdef LINUX_THREADS
- // LinuxThreads usurps both SIGUSR1 and SIGUSR2.
+ // LinuxThreads (prior to glibc 2.1) usurps both SIGUSR1 and SIGUSR2.
# define INTR SIGHUP
#else /* LINUX_THREADS */
# define INTR SIGUSR2
@@ -72,8 +75,6 @@
#define FLAG_START 0x01
// Thread is daemon.
#define FLAG_DAEMON 0x02
-// Thread was interrupted by _Jv_ThreadInterrupt.
-#define FLAG_INTERRUPTED 0x04
@@ -86,58 +87,82 @@
int r;
pthread_mutex_t *pmu = _Jv_PthreadGetMutex (mu);
- struct timespec ts;
+ struct timespec ts;
jlong m, m2, startTime;
bool done_sleeping = false;
if (millis == 0 && nanos == 0)
- r = pthread_cond_wait (cv, pmu);
+ {
+#ifdef LINUX_THREADS
+ // pthread_cond_timedwait can be interrupted by a signal on linux, while
+ // pthread_cond_wait can not. So pthread_cond_timedwait() forever.
+ m = java::lang::Long::MAX_VALUE;
+ ts.tv_sec = LONG_MAX;
+ ts.tv_nsec = 0;
+#endif
+ }
else
{
startTime = java::lang::System::currentTimeMillis();
m = millis + startTime;
+ ts.tv_sec = m / 1000;
+ ts.tv_nsec = ((m % 1000) * 1000000) + nanos;
+ }
- do
- {
- ts.tv_sec = m / 1000;
- ts.tv_nsec = ((m % 1000) * 1000000) + nanos;
+ java::lang::Thread *current = _Jv_ThreadCurrent();
+ do
+ {
+ r = EINTR;
+ // Check to ensure the thread hasn't already been interrupted.
+ if (!(current->isInterrupted ()))
+ {
+#ifdef LINUX_THREADS
+ // FIXME: in theory, interrupt() could be called on this thread
+ // between the test above and the wait below, resulting in the
+ // interupt() call failing. I don't see a way to fix this
+ // without significant changes to the implementation.
r = pthread_cond_timedwait (cv, pmu, &ts);
-
- if (r == EINTR)
+#else
+ if (millis == 0 && nanos == 0)
+ r = pthread_cond_wait (cv, pmu);
+ else
+ r = pthread_cond_timedwait (cv, pmu, &ts);
+#endif
+ }
+
+ if (r == EINTR)
+ {
+ /* We were interrupted by a signal. Either this is
+ because we were interrupted intentionally (i.e. by
+ Thread.interrupt()) or by the GC if it is
+ signal-based. */
+ if (current->isInterrupted ())
{
- /* We were interrupted by a signal. Either this is
- because we were interrupted intentionally (i.e. by
- Thread.interrupt()) or by the GC if it is
- signal-based. */
- _Jv_Thread_t *current = _Jv_ThreadCurrentData();
- if (current->flags & FLAG_INTERRUPTED)
+ r = 0;
+ done_sleeping = true;
+ }
+ else
+ {
+ /* We were woken up by the GC or another signal. */
+ m2 = java::lang::System::currentTimeMillis ();
+ if (m2 >= m)
{
- current->flags &= ~(FLAG_INTERRUPTED);
- done_sleeping = true;
- }
- else
- {
- /* We were woken up by the GC or another signal. */
- m2 = java::lang::System::currentTimeMillis ();
- if (m2 >= m)
- {
- r = 0;
- done_sleeping = true;
- }
+ r = 0;
+ done_sleeping = true;
}
}
- else if (r == ETIMEDOUT)
- {
- /* A timeout is a normal result. */
- r = 0;
- done_sleeping = true;
- }
- else
- done_sleeping = true;
}
- while (! done_sleeping);
+ else if (r == ETIMEDOUT)
+ {
+ /* A timeout is a normal result. */
+ r = 0;
+ done_sleeping = true;
+ }
+ else
+ done_sleeping = true;
}
+ while (! done_sleeping);
return r != 0;
}
@@ -272,20 +297,12 @@
sigemptyset (&act.sa_mask);
act.sa_flags = 0;
sigaction (INTR, &act, NULL);
-
- // Arrange for SIGINT to be blocked to all threads. It is only
- // deliverable to the master thread.
- sigset_t mask;
- sigemptyset (&mask);
- sigaddset (&mask, SIGINT);
- pthread_sigmask (SIG_BLOCK, &mask, NULL);
}
void
_Jv_ThreadInitData (_Jv_Thread_t **data, java::lang::Thread *)
{
_Jv_Thread_t *info = new _Jv_Thread_t;
-
info->flags = 0;
// FIXME register a finalizer for INFO here.
@@ -361,20 +378,20 @@
}
else
data->flags |= FLAG_DAEMON;
- pthread_create (&data->thread, &attr, really_start, (void *) info);
-
+ int r = pthread_create (&data->thread, &attr, really_start, (void *) info);
+
pthread_attr_destroy (&attr);
+
+ if (r)
+ {
+ const char* msg = "Cannot create additional threads";
+ JvThrow (new java::lang::OutOfMemoryError (JvNewStringUTF (msg)));
+ }
}
void
_Jv_ThreadWait (void)
{
- // Arrange for SIGINT to be delivered to the master thread.
- sigset_t mask;
- sigemptyset (&mask);
- sigaddset (&mask, SIGINT);
- pthread_sigmask (SIG_UNBLOCK, &mask, NULL);
-
pthread_mutex_lock (&daemon_mutex);
if (non_daemon_count)
pthread_cond_wait (&daemon_cond, &daemon_mutex);
@@ -384,6 +401,5 @@
void
_Jv_ThreadInterrupt (_Jv_Thread_t *data)
{
- data->flags |= FLAG_INTERRUPTED;
pthread_kill (data->thread, INTR);
}