lib/net: set the file descriptor to non-block on ReregisterRead

In case the user of poll changes the fd flags to block for reading
or writing and forgot to set it non-block again, this may cause an issue
on the poll.

2 files changed, 13 insertions, 2 deletions

diff --git a/lib/net/poll_bsd.go b/lib/net/poll_bsd.go
index e8ff5d69..813f131c 100644
--- a/lib/net/poll_bsd.go
+++ b/lib/net/poll_bsd.go
@@ -9,6 +9,7 @@ package net
 
 import (
 	"fmt"
+	"log"
 
 	"golang.org/x/sys/unix"
 )
@@ -60,7 +61,10 @@ func (poll *kqueue) RegisterRead(fd int) (err error) {
 }
 
 func (poll *kqueue) ReregisterRead(idx, fd int) {
-	// no-op
+	var err = unix.SetNonblock(fd, true)
+	if err != nil {
+		log.Printf(`ReregisterRead: %s`, err)
+	}
 }
 
 func (poll *kqueue) UnregisterRead(fd int) (err error) {
diff --git a/lib/net/poll_linux.go b/lib/net/poll_linux.go
index 5dfc7d69..075f8aa3 100644
--- a/lib/net/poll_linux.go
+++ b/lib/net/poll_linux.go
@@ -58,9 +58,16 @@ func (poll *epoll) RegisterRead(fd int) (err error) {
 }
 
 func (poll *epoll) ReregisterRead(idx, fd int) {
+	var err error
+
 	poll.events[idx].Events = unix.EPOLLIN | unix.EPOLLONESHOT
 
-	err := unix.EpollCtl(poll.read, unix.EPOLL_CTL_MOD, fd, &poll.events[idx])
+	err = unix.SetNonblock(fd, true)
+	if err != nil {
+		log.Printf("epoll.ReregisterRead: %s", err.Error())
+	}
+
+	err = unix.EpollCtl(poll.read, unix.EPOLL_CTL_MOD, fd, &poll.events[idx])
 	if err != nil {
 		log.Println("epoll.RegisterRead: unix.EpollCtl: " + err.Error())
 		err = poll.UnregisterRead(fd)