Provide versions of mutex, condvar, and aio init that never fail.

If the underlying platform fails (FreeBSD is the only one I'm aware
of that does this!), we use a global lock or condition variable instead.
This means that our lock initializers never ever fail.

Probably we could eliminate most of this for Linux and Darwin, since
on those platforms, mutex and condvar initialization reasonably never
fails.  Initial benchmarks show little difference either way -- so we
can revisit (optimize) later.

This removes a lot of otherwise untested code in error cases and so forth,
improving coverage and resilience in the face of allocation failures.

Platforms other than POSIX should follow a similar pattern if they need
this.  (VxWorks, I'm thinking of you.)  Most sane platforms won't have
an issue here, since normally these initializations do not need to allocate
memory. (Reportedly, even FreeBSD has plans to "fix" this in libthr2.)

While here, some bugs were fixed in initialization & teardown.

The fallback code is properly tested with dedicated test cases.

2 files changed, 23 insertions, 68 deletions

diff --git a/src/protocol/survey/respond.c b/src/protocol/survey/respond.c
index 32513134..a097f551 100644
--- a/src/protocol/survey/respond.c
+++ b/src/protocol/survey/respond.c
@@ -77,6 +77,11 @@ nni_resp_sock_init(void **pp, nni_sock *nsock)
 	if ((psock = NNI_ALLOC_STRUCT(psock)) == NULL) {
 		return (NNG_ENOMEM);
 	}
+	if ((rv = nni_idhash_init(&psock->pipes)) != 0) {
+		NNI_FREE_STRUCT(psock);
+		return (rv);
+	}
+
 	psock->ttl        = 8; // Per RFC
 	psock->nsock      = nsock;
 	psock->raw        = 0;
@@ -85,24 +90,12 @@ nni_resp_sock_init(void **pp, nni_sock *nsock)
 	psock->urq        = nni_sock_recvq(nsock);
 	psock->uwq        = nni_sock_sendq(nsock);
 
-	if ((rv = nni_mtx_init(&psock->mtx)) != 0) {
-		goto fail;
-	}
-	if ((rv = nni_idhash_init(&psock->pipes)) != 0) {
-		goto fail;
-	}
-	rv = nni_aio_init(&psock->aio_getq, nni_resp_sock_getq_cb, psock);
-	if (rv != 0) {
-		goto fail;
-	}
+	nni_mtx_init(&psock->mtx);
+	nni_aio_init(&psock->aio_getq, nni_resp_sock_getq_cb, psock);
 
 	*pp = psock;
 	nni_sock_senderr(nsock, NNG_ESTATE);
 	return (0);
-
-fail:
-	nni_resp_sock_fini(psock);
-	return (rv);
 }
 
 static void
@@ -131,33 +124,18 @@ nni_resp_pipe_init(void **pp, nni_pipe *npipe, void *psock)
 		return (NNG_ENOMEM);
 	}
 	if ((rv = nni_msgq_init(&ppipe->sendq, 2)) != 0) {
-		goto fail;
-	}
-	rv = nni_aio_init(&ppipe->aio_putq, nni_resp_putq_cb, ppipe);
-	if (rv != 0) {
-		goto fail;
-	}
-	rv = nni_aio_init(&ppipe->aio_recv, nni_resp_recv_cb, ppipe);
-	if (rv != 0) {
-		goto fail;
-	}
-	rv = nni_aio_init(&ppipe->aio_getq, nni_resp_getq_cb, ppipe);
-	if (rv != 0) {
-		goto fail;
-	}
-	rv = nni_aio_init(&ppipe->aio_send, nni_resp_send_cb, ppipe);
-	if (rv != 0) {
-		goto fail;
+		NNI_FREE_STRUCT(ppipe);
+		return (rv);
 	}
+	nni_aio_init(&ppipe->aio_putq, nni_resp_putq_cb, ppipe);
+	nni_aio_init(&ppipe->aio_recv, nni_resp_recv_cb, ppipe);
+	nni_aio_init(&ppipe->aio_getq, nni_resp_getq_cb, ppipe);
+	nni_aio_init(&ppipe->aio_send, nni_resp_send_cb, ppipe);
 
 	ppipe->npipe = npipe;
 	ppipe->psock = psock;
 	*pp          = ppipe;
 	return (0);
-
-fail:
-	nni_resp_pipe_fini(ppipe);
-	return (rv);
 }
 
 static void
diff --git a/src/protocol/survey/survey.c b/src/protocol/survey/survey.c
index cb90c13f..2a32f289 100644
--- a/src/protocol/survey/survey.c
+++ b/src/protocol/survey/survey.c
@@ -70,19 +70,13 @@ static int
 nni_surv_sock_init(void **sp, nni_sock *nsock)
 {
 	nni_surv_sock *psock;
-	int            rv;
 
 	if ((psock = NNI_ALLOC_STRUCT(psock)) == NULL) {
 		return (NNG_ENOMEM);
 	}
-	if ((rv = nni_mtx_init(&psock->mtx)) != 0) {
-		goto fail;
-	}
-	rv = nni_aio_init(&psock->aio_getq, nni_surv_sock_getq_cb, psock);
-	if (rv != 0) {
-		goto fail;
-	}
 	NNI_LIST_INIT(&psock->pipes, nni_surv_pipe, node);
+	nni_mtx_init(&psock->mtx);
+	nni_aio_init(&psock->aio_getq, nni_surv_sock_getq_cb, psock);
 	nni_timer_init(&psock->timer, nni_surv_timeout, psock);
 
 	psock->nextid   = nni_random();
@@ -96,10 +90,6 @@ nni_surv_sock_init(void **sp, nni_sock *nsock)
 	*sp = psock;
 	nni_sock_recverr(nsock, NNG_ESTATE);
 	return (0);
-
-fail:
-	nni_surv_sock_fini(psock);
-	return (rv);
 }
 
 static void
@@ -143,32 +133,19 @@ nni_surv_pipe_init(void **pp, nni_pipe *npipe, void *psock)
 	}
 	// This depth could be tunable.
 	if ((rv = nni_msgq_init(&ppipe->sendq, 16)) != 0) {
-		goto failed;
-	}
-	rv = nni_aio_init(&ppipe->aio_getq, nni_surv_getq_cb, ppipe);
-	if (rv != 0) {
-		goto failed;
-	}
-	rv = nni_aio_init(&ppipe->aio_putq, nni_surv_putq_cb, ppipe);
-	if (rv != 0) {
-		goto failed;
-	}
-	rv = nni_aio_init(&ppipe->aio_send, nni_surv_send_cb, ppipe);
-	if (rv != 0) {
-		goto failed;
-	}
-	rv = nni_aio_init(&ppipe->aio_recv, nni_surv_recv_cb, ppipe);
-	if (rv != 0) {
-		goto failed;
+		NNI_FREE_STRUCT(ppipe);
+		return (rv);
 	}
+
+	nni_aio_init(&ppipe->aio_getq, nni_surv_getq_cb, ppipe);
+	nni_aio_init(&ppipe->aio_putq, nni_surv_putq_cb, ppipe);
+	nni_aio_init(&ppipe->aio_send, nni_surv_send_cb, ppipe);
+	nni_aio_init(&ppipe->aio_recv, nni_surv_recv_cb, ppipe);
+
 	ppipe->npipe = npipe;
 	ppipe->psock = psock;
 	*pp          = ppipe;
 	return (0);
-
-failed:
-	nni_surv_pipe_fini(ppipe);
-	return (rv);
 }
 
 static int