tools/bpf: make libbpf _GNU_SOURCE friendly
authorYonghong Song <yhs@fb.com>
Thu, 29 Nov 2018 23:31:45 +0000 (15:31 -0800)
committerDaniel Borkmann <daniel@iogearbox.net>
Fri, 30 Nov 2018 01:41:02 +0000 (02:41 +0100)
commitb42699547fc9fb1057795bccc21a6445743a7fde
tree8389d04f1a6408da4c1f729618de4eff7c51dfdb
parent1ad93ab10e24856ea1ae9f0fd3352992afa67e1b
tools/bpf: make libbpf _GNU_SOURCE friendly

During porting libbpf to bcc, I got some warnings like below:
  ...
  [  2%] Building C object src/cc/CMakeFiles/bpf-shared.dir/libbpf/src/libbpf.c.o
  /home/yhs/work/bcc2/src/cc/libbpf/src/libbpf.c:12:0:
  warning: "_GNU_SOURCE" redefined [enabled by default]
   #define _GNU_SOURCE
  ...
  [  3%] Building C object src/cc/CMakeFiles/bpf-shared.dir/libbpf/src/libbpf_errno.c.o
  /home/yhs/work/bcc2/src/cc/libbpf/src/libbpf_errno.c: In function ‘libbpf_strerror’:
  /home/yhs/work/bcc2/src/cc/libbpf/src/libbpf_errno.c:45:7:
  warning: assignment makes integer from pointer without a cast [enabled by default]
     ret = strerror_r(err, buf, size);
  ...

bcc is built with _GNU_SOURCE defined and this caused the above warning.
This patch intends to make libpf _GNU_SOURCE friendly by
  . define _GNU_SOURCE in libbpf.c unless it is not defined
  . undefine _GNU_SOURCE as non-gnu version of strerror_r is expected.

Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
tools/lib/bpf/libbpf.c
tools/lib/bpf/libbpf_errno.c