Because it is very hard to make fork(2) from threaded process safe (we are

limited to async-signal safe functions in the child process), move all hooks
execution to the main (non-threaded) process.

Do it by maintaining connection (socketpair) between child and parent
and sending events from the child to parent, so it can execute the hook.

This is step in right direction for others reasons too. For example there is
one less problem to drop privs in worker processes.

MFC after:	2 weeks
Obtained from:	Wheel Systems Sp. z o.o. http://www.wheelsystems.com

1 files changed, 17 insertions, 4 deletions

diff --git a/sbin/hastd/secondary.c b/sbin/hastd/secondary.c
index d1575e8..14016f7 100644
--- a/sbin/hastd/secondary.c
+++ b/sbin/hastd/secondary.c
@@ -54,6 +54,7 @@ __FBSDID("$FreeBSD$");
 #include <pjdlog.h>
 
 #include "control.h"
+#include "event.h"
 #include "hast.h"
 #include "hast_proto.h"
 #include "hastd.h"
@@ -325,7 +326,7 @@ init_remote(struct hast_resource *res, struct nv *nvin)
 	if (res->hr_secondary_localcnt > res->hr_primary_remotecnt &&
 	     res->hr_primary_localcnt > res->hr_secondary_remotecnt) {
 		/* Exit on split-brain. */
-		hook_exec(res->hr_exec, "split-brain", res->hr_name, NULL);
+		event_send(res, EVENT_SPLITBRAIN);
 		exit(EX_CONFIG);
 	}
 }
@@ -345,6 +346,14 @@ hastd_secondary(struct hast_resource *res, struct nv *nvin)
 		pjdlog_exit(EX_OSERR,
 		    "Unable to create control sockets between parent and child");
 	}
+	/*
+	 * Create communication channel between child and parent.
+	 */
+	if (proto_client("socketpair://", &res->hr_event) < 0) {
+		KEEP_ERRNO((void)pidfile_remove(pfh));
+		pjdlog_exit(EX_OSERR,
+		    "Unable to create event sockets between child and parent");
+	}
 
 	pid = fork();
 	if (pid < 0) {
@@ -358,6 +367,8 @@ hastd_secondary(struct hast_resource *res, struct nv *nvin)
 		res->hr_remotein = NULL;
 		proto_close(res->hr_remoteout);
 		res->hr_remoteout = NULL;
+		/* Declare that we are receiver. */
+		proto_recv(res->hr_event, NULL, 0);
 		res->hr_workerpid = pid;
 		return;
 	}
@@ -372,17 +383,19 @@ hastd_secondary(struct hast_resource *res, struct nv *nvin)
 	signal(SIGHUP, SIG_DFL);
 	signal(SIGCHLD, SIG_DFL);
 
+	/* Declare that we are sender. */
+	proto_send(res->hr_event, NULL, 0);
+
 	/* Error in setting timeout is not critical, but why should it fail? */
 	if (proto_timeout(res->hr_remotein, 0) < 0)
 		pjdlog_errno(LOG_WARNING, "Unable to set connection timeout");
 	if (proto_timeout(res->hr_remoteout, res->hr_timeout) < 0)
 		pjdlog_errno(LOG_WARNING, "Unable to set connection timeout");
 
-	hook_init();
 	init_local(res);
 	init_remote(res, nvin);
 	init_environment();
-	hook_exec(res->hr_exec, "connect", res->hr_name, NULL);
+	event_send(res, EVENT_CONNECT);
 
 	error = pthread_create(&td, NULL, recv_thread, res);
 	assert(error == 0);
@@ -515,7 +528,7 @@ secondary_exit(int exitcode, const char *fmt, ...)
 	va_start(ap, fmt);
 	pjdlogv_errno(LOG_ERR, fmt, ap);
 	va_end(ap);
-	hook_exec(gres->hr_exec, "disconnect", gres->hr_name, NULL);
+	event_send(gres, EVENT_DISCONNECT);
 	exit(exitcode);
 }