From 78f4b87c3f014e378377d3ecc55d1ec46cd57b51 Mon Sep 17 00:00:00 2001
From: Andrea Claudi <aclaudi@redhat.com>
Date: Mon, 29 Apr 2019 20:08:08 +0200
Subject: [PATCH] lib/bpf: Check return value of write()

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1465646
Upstream Status: iproute2.git commit b5c78e1b2c868

commit b5c78e1b2c8681e82684f47563acd3d383893658
Author: Phil Sutter <phil@nwl.cc>
Date:   Thu Aug 24 11:41:29 2017 +0200

    lib/bpf: Check return value of write()

    This is merely to silence the compiler warning. If write to stderr
    failed, assume that printing an error message will fail as well so don't
    even try.

    Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 lib/bpf.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/bpf.c b/lib/bpf.c
index 33c5288e82187..7eb754ad7cb56 100644
--- a/lib/bpf.c
+++ b/lib/bpf.c
@@ -486,7 +486,8 @@ int bpf_trace_pipe(void)
 
 		ret = read(fd, buff, sizeof(buff) - 1);
 		if (ret > 0) {
-			write(2, buff, ret);
+			if (write(STDERR_FILENO, buff, ret) != ret)
+				return -1;
 			fflush(stderr);
 		}
 	}
-- 
2.20.1