From 782898ed3aabd9611386db6e72370d2cf7941a02 Mon Sep 17 00:00:00 2001
From: Timo Kokkonen <timo.t.kokkonen@iki.fi>
Date: Sun, 11 Oct 2020 11:55:42 +0300
Subject: [PATCH] register_event_handler: Make also modifications and deletes
 possible

Take the op parameter as an argument that is given to
epoll_ctl(). This way the function can also modify and delete epoll
events.

Signed-off-by: Timo Kokkonen <timo.t.kokkonen@iki.fi>
---
 process.c | 27 +++++++++++++++++++++++----
 process.h |  3 ++-
 2 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/process.c b/process.c
index 96c93f8..8a4059b 100644
--- a/process.c
+++ b/process.c
@@ -574,10 +574,11 @@ print:
 	return 0;
 }
 
-int register_event_handler(struct event_handler *handler)
+int register_event_handler(struct event_handler *handler, int op)
 {
 	struct epoll_event ev;
 	int ret;
+	const char *str;
 
 	if (handler->fd <= 0) {
 		pr_err("Invalid file descriptor of %d\n", handler->fd);
@@ -589,15 +590,33 @@ int register_event_handler(struct event_handler *handler)
 		return -1;
 	}
 
-	pr_info("Registering handler for %s, fd %d\n",
+	switch (op) {
+	case EPOLL_CTL_ADD:
+		str = "register";
+		break;
+
+	case EPOLL_CTL_MOD:
+		str = "modify";
+		break;
+
+	case EPOLL_CTL_DEL:
+		str = "deregister";
+		break;
+
+	default:
+		pr_err("Invalid op %d\n", op);
+		return -1;
+	}
+
+	pr_info("Doing a epoll %s for handler %s, fd %d\n", str,
 		handler->name, handler->fd);
 
 	ev.data.fd = handler->fd;
 	ev.data.ptr = handler;
 	ev.events = handler->events;
-	ret = epoll_ctl(epoll_fd, EPOLL_CTL_ADD, handler->fd, &ev);
+	ret = epoll_ctl(epoll_fd, op, handler->fd, &ev);
 	if (ret) {
-		pr_err("Failed to add epoll_fd: %m\n");
+		pr_err("Failed to do epoll_ctl %s: %m\n", str);
 		return -1;
 	}
 
diff --git a/process.h b/process.h
index 0971a71..1b92e5b 100644
--- a/process.h
+++ b/process.h
@@ -9,6 +9,7 @@
 #include <error.h>
 #include <errno.h>
 #include <stdint.h>
+#include <sys/epoll.h>
 
 struct event_handler;
 
@@ -22,7 +23,7 @@ struct event_handler {
 	char *name;
 };
 
-int register_event_handler(struct event_handler *handler);
+int register_event_handler(struct event_handler *handler, int op);
 
 int init_jobcontrol(int max_jobs_requested);
 int poll_job_requests(int timeout);
-- 
2.45.0