From 986fdf471ba639108ad043e0a9276060f923d274 Mon Sep 17 00:00:00 2001
From: Rusty Bird <rustybird@net-c.com>
Date: Mon, 16 Jan 2023 12:57:17 +0000
Subject: [PATCH] split-browser: Increase pipe capacity

To avoid a hang before DisposableVM launch if the user has configured
very many pref() lines, try to increase the capacity of the named pipe
from 64 KiB to 1 MiB (the default for the fs.pipe-max-size sysctl).
---
 vm/qubes-split-browser/usr/bin/split-browser | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/vm/qubes-split-browser/usr/bin/split-browser b/vm/qubes-split-browser/usr/bin/split-browser
index 4384ea1..6889d7d 100755
--- a/vm/qubes-split-browser/usr/bin/split-browser
+++ b/vm/qubes-split-browser/usr/bin/split-browser
@@ -89,9 +89,13 @@ dispvm() (
     mkfifo -- "$SB_CMD_INPUT".tmp
     exec {cmd_fd}<>"$SB_CMD_INPUT".tmp
 
+    # 1031 is fcntl.F_SETPIPE_SZ in Python 3.10+
+    python3 -Sc 'import fcntl; fcntl.fcntl(0, 1031, 1024**2)' <&"$cmd_fd" ||
+    true
+
     d=/etc/qubes-rpc
     bash_line="PATH=/usr/local$d:$d:\$PATH exec split-browser-disp"
-    printf '%s\n' "$bash_line" "$@" >&"$cmd_fd"  # 64 KB pipe capacity
+    printf '%s\n' "$bash_line" "$@" >&"$cmd_fd"
     mv -T -- "$SB_CMD_INPUT"{.tmp,}
 
     {