Copy files from ../librthread in preparation for moving functionality

from libpthread to libc.  No changes to the build yet, just making it
easier to review the substantive diffs.

ok beck@ kettenis@ tedu@

1 files changed, 288 insertions, 0 deletions

diff --git a/lib/libc/thread/rthread_mutex.c b/lib/libc/thread/rthread_mutex.c
new file mode 100644
index 00000000000..73a87180086
--- /dev/null
+++ b/lib/libc/thread/rthread_mutex.c
@@ -0,0 +1,288 @@
+/*	$OpenBSD: rthread_mutex.c,v 1.1 2017/08/15 06:13:24 guenther Exp $ */
+/*
+ * Copyright (c) 2017 Martin Pieuchot <mpi@openbsd.org>
+ * Copyright (c) 2012 Philip Guenther <guenther@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <assert.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include <pthread.h>
+
+#include "rthread.h"
+#include "cancel.h"
+#include "synch.h"
+
+/*
+ * States defined in "Futexes Are Tricky" 5.2
+ */
+enum {
+	UNLOCKED = 0,
+	LOCKED = 1,	/* locked without waiter */
+	CONTENDED = 2,	/* threads waiting for this mutex */
+};
+
+#define SPIN_COUNT	128
+#if defined(__i386__) || defined(__amd64__)
+#define SPIN_WAIT()	asm volatile("pause": : : "memory")
+#else
+#define SPIN_WAIT()	do { } while (0)
+#endif
+
+static _atomic_lock_t static_init_lock = _SPINLOCK_UNLOCKED;
+
+int
+pthread_mutex_init(pthread_mutex_t *mutexp, const pthread_mutexattr_t *attr)
+{
+	pthread_mutex_t mutex;
+
+	mutex = calloc(1, sizeof(*mutex));
+	if (mutex == NULL)
+		return (ENOMEM);
+
+	if (attr == NULL) {
+		mutex->type = PTHREAD_MUTEX_DEFAULT;
+		mutex->prioceiling = -1;
+	} else {
+		mutex->type = (*attr)->ma_type;
+		mutex->prioceiling = (*attr)->ma_protocol ==
+		    PTHREAD_PRIO_PROTECT ? (*attr)->ma_prioceiling : -1;
+	}
+	*mutexp = mutex;
+
+	return (0);
+}
+DEF_STD(pthread_mutex_init);
+
+int
+pthread_mutex_destroy(pthread_mutex_t *mutexp)
+{
+	pthread_mutex_t mutex;
+
+	if (mutexp == NULL || *mutexp == NULL)
+		return (EINVAL);
+
+	mutex = *mutexp;
+	if (mutex) {
+		if (mutex->lock != UNLOCKED) {
+#define MSG "pthread_mutex_destroy on mutex with waiters!\n"
+			write(2, MSG, sizeof(MSG) - 1);
+#undef MSG
+			return (EBUSY);
+		}
+		free((void *)mutex);
+		*mutexp = NULL;
+	}
+
+	return (0);
+}
+DEF_STD(pthread_mutex_destroy);
+
+static int
+_rthread_mutex_trylock(pthread_mutex_t mutex, int trywait,
+    const struct timespec *abs)
+{
+	pthread_t self = pthread_self();
+
+	if (atomic_cas_uint(&mutex->lock, UNLOCKED, LOCKED) == UNLOCKED) {
+		membar_enter_after_atomic();
+		mutex->owner = self;
+		return (0);
+	}
+
+	if (mutex->owner == self) {
+		int type = mutex->type;
+
+		/* already owner?  handle recursive behavior */
+		if (type != PTHREAD_MUTEX_RECURSIVE) {
+			if (trywait || type == PTHREAD_MUTEX_ERRORCHECK)
+				return (trywait ? EBUSY : EDEADLK);
+
+			/* self-deadlock is disallowed by strict */
+			if (type == PTHREAD_MUTEX_STRICT_NP && abs == NULL)
+				abort();
+
+			/* self-deadlock, possibly until timeout */
+			while (_twait(&mutex->type, type, CLOCK_REALTIME,
+			    abs) != ETIMEDOUT)
+				;
+			return (ETIMEDOUT);
+		} else {
+			if (mutex->count == INT_MAX)
+				return (EAGAIN);
+			mutex->count++;
+			return (0);
+		}
+	}
+
+	return (EBUSY);
+}
+
+static int
+_rthread_mutex_timedlock(pthread_mutex_t *mutexp, int trywait,
+    const struct timespec *abs, int timed)
+{
+	pthread_t self = pthread_self();
+	pthread_mutex_t mutex;
+	unsigned int i, lock;
+	int error = 0;
+
+	if (mutexp == NULL)
+		return (EINVAL);
+
+	/*
+	 * If the mutex is statically initialized, perform the dynamic
+	 * initialization. Note: _thread_mutex_lock() in libc requires
+	 * pthread_mutex_lock() to perform the mutex init when *mutexp
+	 * is NULL.
+	 */
+	if (*mutexp == NULL) {
+		_spinlock(&static_init_lock);
+		if (*mutexp == NULL)
+			error = pthread_mutex_init(mutexp, NULL);
+		_spinunlock(&static_init_lock);
+		if (error != 0)
+			return (EINVAL);
+	}
+
+	mutex = *mutexp;
+	_rthread_debug(5, "%p: mutex_%slock %p (%p)\n", self,
+	    (timed ? "timed" : (trywait ? "try" : "")), (void *)mutex,
+	    (void *)mutex->owner);
+
+	error = _rthread_mutex_trylock(mutex, trywait, abs);
+	if (error != EBUSY || trywait)
+		return (error);
+
+	/* Try hard to not enter the kernel. */
+	for (i = 0; i < SPIN_COUNT; i ++) {
+		if (mutex->lock == UNLOCKED)
+			break;
+
+		SPIN_WAIT();
+	}
+
+	lock = atomic_cas_uint(&mutex->lock, UNLOCKED, LOCKED);
+	if (lock == UNLOCKED) {
+		membar_enter_after_atomic();
+		mutex->owner = self;
+		return (0);
+	}
+
+	if (lock != CONTENDED) {
+		/* Indicate that we're waiting on this mutex. */
+		lock = atomic_swap_uint(&mutex->lock, CONTENDED);
+	}
+
+	while (lock != UNLOCKED) {
+		error = _twait(&mutex->lock, CONTENDED, CLOCK_REALTIME, abs);
+		if (error == ETIMEDOUT)
+			return (error);
+		/*
+		 * We cannot know if there's another waiter, so in
+		 * doubt set the state to CONTENDED.
+		 */
+		lock = atomic_swap_uint(&mutex->lock, CONTENDED);
+	};
+
+	membar_enter_after_atomic();
+	mutex->owner = self;
+	return (0);
+}
+
+int
+pthread_mutex_trylock(pthread_mutex_t *mutexp)
+{
+	return (_rthread_mutex_timedlock(mutexp, 1, NULL, 0));
+}
+
+int
+pthread_mutex_timedlock(pthread_mutex_t *mutexp, const struct timespec *abs)
+{
+	return (_rthread_mutex_timedlock(mutexp, 0, abs, 1));
+}
+
+int
+pthread_mutex_lock(pthread_mutex_t *mutexp)
+{
+	return (_rthread_mutex_timedlock(mutexp, 0, NULL, 0));
+}
+DEF_STD(pthread_mutex_lock);
+
+int
+pthread_mutex_unlock(pthread_mutex_t *mutexp)
+{
+	pthread_t self = pthread_self();
+	pthread_mutex_t mutex;
+
+	if (mutexp == NULL)
+		return (EINVAL);
+
+	if (*mutexp == NULL)
+#if PTHREAD_MUTEX_DEFAULT == PTHREAD_MUTEX_ERRORCHECK
+		return (EPERM);
+#elif PTHREAD_MUTEX_DEFAULT == PTHREAD_MUTEX_NORMAL
+		return(0);
+#else
+		abort();
+#endif
+
+	mutex = *mutexp;
+	_rthread_debug(5, "%p: mutex_unlock %p (%p)\n", self, (void *)mutex,
+	    (void *)mutex->owner);
+
+	if (mutex->owner != self) {
+	_rthread_debug(5, "%p: different owner %p (%p)\n", self, (void *)mutex,
+	    (void *)mutex->owner);
+		if (mutex->type == PTHREAD_MUTEX_ERRORCHECK ||
+		    mutex->type == PTHREAD_MUTEX_RECURSIVE) {
+			return (EPERM);
+		} else {
+			/*
+			 * For mutex type NORMAL our undefined behavior for
+			 * unlocking an unlocked mutex is to succeed without
+			 * error.  All other undefined behaviors are to
+			 * abort() immediately.
+			 */
+			if (mutex->owner == NULL &&
+			    mutex->type == PTHREAD_MUTEX_NORMAL)
+				return (0);
+			else
+				abort();
+
+		}
+	}
+
+	if (mutex->type == PTHREAD_MUTEX_RECURSIVE) {
+		if (mutex->count > 0) {
+			mutex->count--;
+			return (0);
+		}
+	}
+
+	mutex->owner = NULL;
+	membar_exit_before_atomic();
+	if (atomic_dec_int_nv(&mutex->lock) != UNLOCKED) {
+		mutex->lock = UNLOCKED;
+		_wake(&mutex->lock, 1);
+	}
+
+	return (0);
+}
+DEF_STD(pthread_mutex_unlock);