From 4d4cd9cde9e01d4ad9354e6e30ac2f90d13042b2 Mon Sep 17 00:00:00 2001
From: Timo Sirainen <tss@iki.fi>
Date: Fri, 15 Oct 2010 19:04:42 +0100
Subject: [PATCH] epoll: Suggest not-so-UUOC if epoll_ctl() fails for stdin

---
 src/lib/ioloop-epoll.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/lib/ioloop-epoll.c b/src/lib/ioloop-epoll.c
index f22bafee92..5f7095b7dc 100644
--- a/src/lib/ioloop-epoll.c
+++ b/src/lib/ioloop-epoll.c
@@ -112,7 +112,9 @@ void io_loop_handle_add(struct io_file *io)
 	if (epoll_ctl(ctx->epfd, op, io->fd, &event) < 0) {
 		if (errno == EPERM && op == EPOLL_CTL_ADD) {
 			i_fatal("epoll_ctl(add, %d) failed: %m "
-				"(fd doesn't support epoll)", io->fd);
+				"(fd doesn't support epoll%s)", io->fd,
+				io->fd != STDIN_FILENO ? "" :
+				" - instead of '<file', try 'cat file|'");
 		}
 		i_panic("epoll_ctl(%s, %d) failed: %m",
 			op == EPOLL_CTL_ADD ? "add" : "mod", io->fd);
-- 
2.47.3