Setup another socketpair between parent and child, so that primary sandboxed

worker can ask the main privileged process to connect in worker's behalf
and then we can migrate descriptor using this socketpair to worker.
This is not really needed now, but will be needed once we start to use
capsicum for sandboxing.

MFC after:	1 week

5 files changed, 143 insertions, 31 deletions

diff --git a/sbin/hastd/control.c b/sbin/hastd/control.c
index 4faf05d..5e18691 100644
--- a/sbin/hastd/control.c
+++ b/sbin/hastd/control.c
@@ -62,6 +62,10 @@ child_cleanup(struct hast_resource *res)
 		proto_close(res->hr_event);
 		res->hr_event = NULL;
 	}
+	if (res->hr_conn != NULL) {
+		proto_close(res->hr_conn);
+		res->hr_conn = NULL;
+	}
 	res->hr_workerpid = 0;
 }
 
diff --git a/sbin/hastd/hast.h b/sbin/hastd/hast.h
index dbbe0da..35a43ef 100644
--- a/sbin/hastd/hast.h
+++ b/sbin/hastd/hast.h
@@ -182,10 +182,12 @@ struct hast_resource {
 	int	hr_previous_role;
 	/* PID of child worker process. 0 - no child. */
 	pid_t	hr_workerpid;
-	/* Control connection between parent and child. */
+	/* Control commands from parent to child. */
 	struct proto_conn *hr_ctrl;
 	/* Events from child to parent. */
 	struct proto_conn *hr_event;
+	/* Connection requests from child to parent. */
+	struct proto_conn *hr_conn;
 
 	/* Activemap structure. */
 	struct activemap *hr_amp;
diff --git a/sbin/hastd/hastd.c b/sbin/hastd/hastd.c
index 5bced2c..cbac4f4 100644
--- a/sbin/hastd/hastd.c
+++ b/sbin/hastd/hastd.c
@@ -214,6 +214,19 @@ descriptors_assert(const struct hast_resource *res, int pjdlogmode)
 				    fd, dtype2str(mode), dtype2str(S_IFSOCK));
 				break;
 			}
+		} else if (fd == proto_descriptor(res->hr_conn)) {
+			if (!isopen) {
+				snprintf(msg, sizeof(msg),
+				    "Descriptor %d (conn) is closed, but should be open.",
+				    fd);
+				break;
+			}
+			if (!S_ISSOCK(mode)) {
+				snprintf(msg, sizeof(msg),
+				    "Descriptor %d (conn) is %s, but should be %s.",
+				    fd, dtype2str(mode), dtype2str(S_IFSOCK));
+				break;
+			}
 		} else if (res->hr_role == HAST_ROLE_SECONDARY &&
 		    fd == proto_descriptor(res->hr_remotein)) {
 			if (!isopen) {
@@ -802,6 +815,41 @@ close:
 }
 
 static void
+connection_migrate(struct hast_resource *res)
+{
+	struct proto_conn *conn;
+	int16_t val = 0;
+
+	if (proto_recv(res->hr_conn, &val, sizeof(val)) < 0) {
+		pjdlog_errno(LOG_WARNING,
+		    "Unable to receive connection command");
+		return;
+	}
+	if (proto_client(res->hr_remoteaddr, &conn) < 0) {
+		val = errno;
+		pjdlog_errno(LOG_WARNING,
+		    "Unable to create outgoing connection to %s",
+		    res->hr_remoteaddr);
+		goto out;
+	}
+	if (proto_connect(conn, -1) < 0) {
+		val = errno;
+		pjdlog_errno(LOG_WARNING, "Unable to connect to %s",
+		    res->hr_remoteaddr);
+		proto_close(conn);
+		goto out;
+	}
+	val = 0;
+out:
+	if (proto_send(res->hr_conn, &val, sizeof(val)) < 0) {
+		pjdlog_errno(LOG_WARNING,
+		    "Unable to send reply to connection request");
+	}
+	if (val == 0 && proto_connection_send(res->hr_conn, conn) < 0)
+		pjdlog_errno(LOG_WARNING, "Unable to send connection");
+}
+
+static void
 main_loop(void)
 {
 	struct hast_resource *res;
@@ -858,10 +906,18 @@ main_loop(void)
 		TAILQ_FOREACH(res, &cfg->hc_resources, hr_next) {
 			if (res->hr_event == NULL)
 				continue;
+			PJDLOG_ASSERT(res->hr_conn != NULL);
 			fd = proto_descriptor(res->hr_event);
 			PJDLOG_ASSERT(fd >= 0);
 			FD_SET(fd, &rfds);
 			maxfd = fd > maxfd ? fd : maxfd;
+			if (res->hr_role == HAST_ROLE_PRIMARY) {
+				/* Only primary workers asks for connections. */
+				fd = proto_descriptor(res->hr_conn);
+				PJDLOG_ASSERT(fd >= 0);
+				FD_SET(fd, &rfds);
+				maxfd = fd > maxfd ? fd : maxfd;
+			}
 		}
 
 		PJDLOG_ASSERT(maxfd + 1 <= (int)FD_SETSIZE);
@@ -882,12 +938,20 @@ main_loop(void)
 		TAILQ_FOREACH(res, &cfg->hc_resources, hr_next) {
 			if (res->hr_event == NULL)
 				continue;
+			PJDLOG_ASSERT(res->hr_conn != NULL);
 			if (FD_ISSET(proto_descriptor(res->hr_event), &rfds)) {
 				if (event_recv(res) == 0)
 					continue;
 				/* The worker process exited? */
 				proto_close(res->hr_event);
 				res->hr_event = NULL;
+				proto_close(res->hr_conn);
+				res->hr_conn = NULL;
+				continue;
+			}
+			if (res->hr_role == HAST_ROLE_PRIMARY &&
+			    FD_ISSET(proto_descriptor(res->hr_conn), &rfds)) {
+				connection_migrate(res);
 			}
 		}
 	}
diff --git a/sbin/hastd/primary.c b/sbin/hastd/primary.c
index 7081096..408edbc 100644
--- a/sbin/hastd/primary.c
+++ b/sbin/hastd/primary.c
@@ -488,6 +488,46 @@ init_local(struct hast_resource *res)
 		exit(EX_NOINPUT);
 }
 
+static int
+primary_connect(struct hast_resource *res, struct proto_conn **connp)
+{
+	struct proto_conn *conn;
+	int16_t val;
+
+	val = 1;
+	if (proto_send(res->hr_conn, &val, sizeof(val)) < 0) {
+		primary_exit(EX_TEMPFAIL,
+		    "Unable to send connection request to parent");
+	}
+	if (proto_recv(res->hr_conn, &val, sizeof(val)) < 0) {
+		primary_exit(EX_TEMPFAIL,
+		    "Unable to receive reply to connection request from parent");
+	}
+	if (val != 0) {
+		errno = val;
+		pjdlog_errno(LOG_WARNING, "Unable to connect to %s",
+		    res->hr_remoteaddr);
+		return (-1);
+	}
+	if (proto_connection_recv(res->hr_conn, true, &conn) < 0) {
+		primary_exit(EX_TEMPFAIL,
+		    "Unable to receive connection from parent");
+	}
+	if (proto_connect_wait(conn, HAST_TIMEOUT) < 0) {
+		pjdlog_errno(LOG_WARNING, "Unable to connect to %s",
+		    res->hr_remoteaddr);
+		proto_close(conn);
+		return (-1);
+	}
+	/* Error in setting timeout is not critical, but why should it fail? */
+	if (proto_timeout(conn, res->hr_timeout) < 0)
+		pjdlog_errno(LOG_WARNING, "Unable to set connection timeout");
+
+	*connp = conn;
+
+	return (0);
+}
+
 static bool
 init_remote(struct hast_resource *res, struct proto_conn **inp,
     struct proto_conn **outp)
@@ -508,21 +548,9 @@ init_remote(struct hast_resource *res, struct proto_conn **inp,
 	in = out = NULL;
 	errmsg = NULL;
 
-	/* Prepare outgoing connection with remote node. */
-	if (proto_client(res->hr_remoteaddr, &out) < 0) {
-		primary_exit(EX_TEMPFAIL,
-		    "Unable to create outgoing connection to %s",
-		    res->hr_remoteaddr);
-	}
-	/* Try to connect, but accept failure. */
-	if (proto_connect(out, HAST_TIMEOUT) < 0) {
-		pjdlog_errno(LOG_WARNING, "Unable to connect to %s",
-		    res->hr_remoteaddr);
-		goto close;
-	}
-	/* Error in setting timeout is not critical, but why should it fail? */
-	if (proto_timeout(out, res->hr_timeout) < 0)
-		pjdlog_errno(LOG_WARNING, "Unable to set connection timeout");
+	if (primary_connect(res, &out) == -1)
+		return (false);
+
 	/*
 	 * First handshake step.
 	 * Setup outgoing connection with remote node.
@@ -576,20 +604,9 @@ init_remote(struct hast_resource *res, struct proto_conn **inp,
 	 * Second handshake step.
 	 * Setup incoming connection with remote node.
 	 */
-	if (proto_client(res->hr_remoteaddr, &in) < 0) {
-		primary_exit(EX_TEMPFAIL,
-		    "Unable to create incoming connection to %s",
-		    res->hr_remoteaddr);
-	}
-	/* Try to connect, but accept failure. */
-	if (proto_connect(in, HAST_TIMEOUT) < 0) {
-		pjdlog_errno(LOG_WARNING, "Unable to connect to %s",
-		    res->hr_remoteaddr);
+	if (primary_connect(res, &in) == -1)
 		goto close;
-	}
-	/* Error in setting timeout is not critical, but why should it fail? */
-	if (proto_timeout(in, res->hr_timeout) < 0)
-		pjdlog_errno(LOG_WARNING, "Unable to set connection timeout");
+
 	nvout = nv_alloc();
 	nv_add_string(nvout, res->hr_name, "resource");
 	nv_add_uint8_array(nvout, res->hr_token, sizeof(res->hr_token),
@@ -792,7 +809,8 @@ hastd_primary(struct hast_resource *res)
 	int error, mode;
 
 	/*
-	 * Create communication channel between parent and child.
+	 * Create communication channel for sending control commands from
+	 * parent to child.
 	 */
 	if (proto_client("socketpair://", &res->hr_ctrl) < 0) {
 		/* TODO: There's no need for this to be fatal error. */
@@ -801,7 +819,7 @@ hastd_primary(struct hast_resource *res)
 		    "Unable to create control sockets between parent and child");
 	}
 	/*
-	 * Create communication channel between child and parent.
+	 * Create communication channel for sending events from child to parent.
 	 */
 	if (proto_client("socketpair://", &res->hr_event) < 0) {
 		/* TODO: There's no need for this to be fatal error. */
@@ -809,6 +827,16 @@ hastd_primary(struct hast_resource *res)
 		pjdlog_exit(EX_OSERR,
 		    "Unable to create event sockets between child and parent");
 	}
+	/*
+	 * Create communication channel for sending connection requests from
+	 * child to parent.
+	 */
+	if (proto_client("socketpair://", &res->hr_conn) < 0) {
+		/* TODO: There's no need for this to be fatal error. */
+		KEEP_ERRNO((void)pidfile_remove(pfh));
+		pjdlog_exit(EX_OSERR,
+		    "Unable to create connection sockets between child and parent");
+	}
 
 	pid = fork();
 	if (pid < 0) {
@@ -821,6 +849,7 @@ hastd_primary(struct hast_resource *res)
 		/* This is parent. */
 		/* Declare that we are receiver. */
 		proto_recv(res->hr_event, NULL, 0);
+		proto_recv(res->hr_conn, NULL, 0);
 		/* Declare that we are sender. */
 		proto_send(res->hr_ctrl, NULL, 0);
 		res->hr_workerpid = pid;
@@ -832,6 +861,7 @@ hastd_primary(struct hast_resource *res)
 
 	/* Declare that we are sender. */
 	proto_send(res->hr_event, NULL, 0);
+	proto_send(res->hr_conn, NULL, 0);
 	/* Declare that we are receiver. */
 	proto_recv(res->hr_ctrl, NULL, 0);
 	descriptors_cleanup(res);
diff --git a/sbin/hastd/secondary.c b/sbin/hastd/secondary.c
index 12a68de..9c859e0 100644
--- a/sbin/hastd/secondary.c
+++ b/sbin/hastd/secondary.c
@@ -364,6 +364,16 @@ hastd_secondary(struct hast_resource *res, struct nv *nvin)
 		pjdlog_exit(EX_OSERR,
 		    "Unable to create event sockets between child and parent");
 	}
+	/*
+	 * Create communication channel for sending connection requests from
+	 * parent to child.
+	 */
+	if (proto_client("socketpair://", &res->hr_conn) < 0) {
+		/* TODO: There's no need for this to be fatal error. */
+		KEEP_ERRNO((void)pidfile_remove(pfh));
+		pjdlog_exit(EX_OSERR,
+		    "Unable to create connection sockets between parent and child");
+	}
 
 	pid = fork();
 	if (pid < 0) {
@@ -381,6 +391,7 @@ hastd_secondary(struct hast_resource *res, struct nv *nvin)
 		proto_recv(res->hr_event, NULL, 0);
 		/* Declare that we are sender. */
 		proto_send(res->hr_ctrl, NULL, 0);
+		proto_send(res->hr_conn, NULL, 0);
 		res->hr_workerpid = pid;
 		return;
 	}
@@ -392,6 +403,7 @@ hastd_secondary(struct hast_resource *res, struct nv *nvin)
 	proto_send(res->hr_event, NULL, 0);
 	/* Declare that we are receiver. */
 	proto_recv(res->hr_ctrl, NULL, 0);
+	proto_recv(res->hr_conn, NULL, 0);
 	descriptors_cleanup(res);
 
 	descriptors_assert(res, mode);