netdev - [PATCH bpf-next] libbpf: Ignore -Wformat-nonliteral warning

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Message-ID: <20190407053734.781995-1-rdna@fb.com>
Date:   Sat, 6 Apr 2019 22:37:34 -0700
From:   Andrey Ignatov <rdna@...com>
To:     <netdev@...r.kernel.org>
CC:     Andrey Ignatov <rdna@...com>, <ast@...nel.org>,
        <daniel@...earbox.net>, <kernel-team@...com>
Subject: [PATCH bpf-next] libbpf: Ignore -Wformat-nonliteral warning

vsprintf() in __base_pr() uses nonliteral format string and it breaks
compilation for those who provide corresponding extra CFLAGS, e.g.:
https://github.com/libbpf/libbpf/issues/27

If libbpf is built with the flags from PR:

  libbpf.c:68:26: error: format string is not a string literal
  [-Werror,-Wformat-nonliteral]
          return vfprintf(stderr, format, args);
                                  ^~~~~~
  1 error generated.

Ignore this warning since the use case in libbpf.c is legit.

Signed-off-by: Andrey Ignatov <rdna@...com>
---
 tools/lib/bpf/libbpf.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index e1e4d35cf08e..1ebfe7943d53 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -52,6 +52,11 @@
 #define BPF_FS_MAGIC		0xcafe4a11
 #endif
 
+/* vsprintf() in __base_pr() uses nonliteral format string. It may break
+ * compilation if user enables corresponding warning. Disable it explicitly.
+ */
+#pragma GCC diagnostic ignored "-Wformat-nonliteral"
+
 #define __printf(a, b)	__attribute__((format(printf, a, b)))
 
 static int __base_pr(enum libbpf_print_level level, const char *format,
-- 
2.17.1