From: Paul Chaignon <paul@isovalent.com>
Date: Mon, 20 Dec 2021 21:45:28 +0000 (+0100)
Subject: bpftool: Enable line buffering for stdout
X-Git-Tag: block-5.17-2022-01-21~91^2~92^2~14
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=1a1a0b0364ad291bd8e509da104ac8b5b1afec5d;p=linux-block.git

bpftool: Enable line buffering for stdout

The output of bpftool prog tracelog is currently buffered, which is
inconvenient when piping the output into other commands. A simple
tracelog | grep will typically not display anything. This patch fixes it
by enabling line buffering on stdout for the whole bpftool binary.

Fixes: 30da46b5dc3a ("tools: bpftool: add a command to dump the trace pipe")
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Paul Chaignon <paul@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20211220214528.GA11706@Mem
---

diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
index 8b71500e7cb2..020e91a542d5 100644
--- a/tools/bpf/bpftool/main.c
+++ b/tools/bpf/bpftool/main.c
@@ -408,6 +408,8 @@ int main(int argc, char **argv)
 	bool version_requested = false;
 	int opt, ret;
 
+	setlinebuf(stdout);
+
 	last_do_help = do_help;
 	pretty_output = false;
 	json_output = false;