From f72a08c80261296f2649bb04c2f3b2552636d404 Mon Sep 17 00:00:00 2001
From: William Casarin <jb55@jb55.com>
Date: Fri, 11 Mar 2022 12:08:59 -0800
Subject: [PATCH] websocketd: fix random failures by blocking stdin reads

Example request that is dying:

NEW REQUEST! lightning_websocketd:main [1955685] <-- bad request from safari

   read 507
   write_all 1
-> websocket_to_lightningd
-> read_payload_header
   read 2
   read_all 1
   read -11      <--- This tried to read a part of the header, is this -EAGAIN?
   read_all 0         should we be blocking on these reads?
   *dies*

Fixes #5089

Changelog-Fixed: `experimental-websocket` intermittent read errors fixed
Signed-off-by: William Casarin <jb55@jb55.com>
---
 connectd/websocketd.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/connectd/websocketd.c b/connectd/websocketd.c
index 324a17f79..9dc65bec2 100644
--- a/connectd/websocketd.c
+++ b/connectd/websocketd.c
@@ -5,6 +5,7 @@
 #include <ccan/base64/base64.h>
 #include <ccan/endian/endian.h>
 #include <ccan/err/err.h>
+#include <ccan/io/io.h>
 #include <ccan/mem/mem.h>
 #include <ccan/read_write_all/read_write_all.h>
 #include <ccan/str/hex/hex.h>
@@ -326,6 +327,7 @@ int main(int argc, char *argv[])
 		errx(1, "Usage: %s", argv[0]);
 
 	/* Do HTTP-style negotiation to get into websocket frames. */
+	io_fd_block(STDIN_FILENO, true);
 	http_upgrade(STDIN_FILENO);
 
 	pfds[0].fd = STDIN_FILENO;