[libqb] [PATCH 4/4] IPC: use rb refcount to check for "connectiveness"

[Angus Salkeld]

This makes it possible the detect the loss of the server
and return -ENOTCONN.

Signed-off-by: Angus Salkeld 
---
 lib/ipc_shm.c |    5 +++++
 lib/ipcc.c    |   53 +++++++++++++++++++++++++++++++++++++++++++++--------
 tests/bmc.c   |    2 +-
 3 files changed, 51 insertions(+), 9 deletions(-)

diff --git a/lib/ipc_shm.c b/lib/ipc_shm.c
index 55670dc..0cf3ecf 100644
--- a/lib/ipc_shm.c
+++ b/lib/ipc_shm.c
@@ -123,6 +123,11 @@ static void qb_ipc_shm_fc_set(struct qb_ipc_one_way *one_way,
 static int32_t qb_ipc_shm_fc_get(struct qb_ipc_one_way *one_way)
 {
    int32_t *fc;
+	int32_t rc = qb_rb_refcount_get(one_way->u.shm.rb);
+
+	if (rc != 2) {
+		return -ENOTCONN;
+	}
    fc = qb_rb_shared_user_data_get(one_way->u.shm.rb);
    return *fc;
 }
diff --git a/lib/ipcc.c b/lib/ipcc.c
index 8248cdd..8ef1812 100644
--- a/lib/ipcc.c
+++ b/lib/ipcc.c
@@ -87,8 +87,17 @@ ssize_t qb_ipcc_send(struct qb_ipcc_connection * c, const void *msg_ptr,
    if (msg_len > c->request.max_msg_size) {
    	return -EINVAL;
    }
-	if (c->funcs.fc_get && c->funcs.fc_get(&c->request)) {
-		return -EAGAIN;
+	if (c->funcs.fc_get) {
+		res = c->funcs.fc_get(&c->request);
+		if (res < 0) {
+			return res;
+		} else if (res > 0) {
+			return -EAGAIN;
+		} else {
+			/*
+			 * we can transmit
+			 */
+		}
    }

res = c->funcs.send(&c->request, msg_ptr, msg_len);
@@ -96,6 +105,9 @@ ssize_t qb_ipcc_send(struct qb_ipcc_connection * c, const void *msg_ptr,
    	do {
    		res2 = qb_ipc_us_send(&c->setup, msg_ptr, 1);
    	} while (res2 == -EAGAIN);
+		if (res2 == -EPIPE) {
+			return -ENOTCONN;
+		}
    	if (res2 != 1) {
    		res = res2;
    	}
@@ -109,6 +121,7 @@ ssize_t qb_ipcc_sendv(struct qb_ipcc_connection* c, const struct iovec* iov,
    int32_t total_size = 0;
    int32_t i;
    int32_t res;
+	int32_t res2;

for (i = 0; i < iov_len; i++) {
    	total_size += iov[i].iov_len;
@@ -117,15 +130,30 @@ ssize_t qb_ipcc_sendv(struct qb_ipcc_connection* c, const struct iovec* iov,
    	return -EINVAL;
    }

-	if (c->funcs.fc_get && c->funcs.fc_get(&c->request)) {
-		return -EAGAIN;
+	if (c->funcs.fc_get) {
+		res = c->funcs.fc_get(&c->request);
+		if (res < 0) {
+			return res;
+		} else if (res > 0) {
+			return -EAGAIN;
+		} else {
+			/*
+			 * we can transmit
+			 */
+		}
    }

res = c->funcs.sendv(&c->request, iov, iov_len);
    if (res > 0 && c->needs_sock_for_poll) {
    	do {
-			res = qb_ipc_us_send(&c->setup, &res, 1);
-		} while (res == -EAGAIN);
+			res2 = qb_ipc_us_send(&c->setup, &res, 1);
+		} while (res2 == -EAGAIN);
+		if (res2 == -EPIPE) {
+			return -ENOTCONN;
+		}
+		if (res2 != 1) {
+			res = res2;
+		}
    }
    return res;
 }
@@ -155,8 +183,17 @@ ssize_t qb_ipcc_sendv_recv(qb_ipcc_connection_t *c,
 {
    ssize_t res = 0;

-	if (c->funcs.fc_get && c->funcs.fc_get(&c->request)) {
-		return -EAGAIN;
+	if (c->funcs.fc_get) {
+		res = c->funcs.fc_get(&c->request);
+		if (res < 0) {
+			return res;
+		} else if (res > 0) {
+			return -EAGAIN;
+		} else {
+			/*
+			 * we can transmit
+			 */
+		}
    }

res = qb_ipcc_sendv(c, iov, iov_len);
diff --git a/tests/bmc.c b/tests/bmc.c
index e49d0e6..85db32d 100644
--- a/tests/bmc.c
+++ b/tests/bmc.c
@@ -88,7 +88,7 @@ repeat_send:
    if (res < 0) {
    	if (res == -EAGAIN) {
    		goto repeat_send;
-		} else if (res == -EINVAL || res == -EINTR) {
+		} else if (res == -EINVAL || res == -EINTR || res == -ENOTCONN) {
    		perror("qb_ipcc_send");
    		return -1;
    	} else {