diff mbox series

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

Message ID 20190407053734.781995-1-rdna@fb.com
State Accepted
Delegated to: BPF Maintainers
Headers show
Series [bpf-next] libbpf: Ignore -Wformat-nonliteral warning | expand

Commit Message

Andrey Ignatov April 7, 2019, 5:37 a.m. UTC
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@fb.com>
---
 tools/lib/bpf/libbpf.c | 5 +++++
 1 file changed, 5 insertions(+)

Comments

Yonghong Song April 7, 2019, 6:11 a.m. UTC | #1
On 4/6/19 10:37 PM, Andrey Ignatov wrote:
> 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@fb.com>

Tested with clang compiler as well. It also resolved the same issue
when using clang to build libbpf in libbpf repo.
Acked-by: Yonghong Song <yhs@fb.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,
>
Alexei Starovoitov April 7, 2019, 6:15 a.m. UTC | #2
On Sat, Apr 06, 2019 at 10:37:34PM -0700, Andrey Ignatov wrote:
> 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@fb.com>

Applied, Thanks
diff mbox series

Patch

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,