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tools/bpf: make libbpf _GNU_SOURCE friendly

PATCH Applied Yonghong Song 3 participants 3 messages Nov 30, 2018

Subsystems (4)
Networking Network drivers BPF libbpf
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Yonghong Song

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#0 lore raw

PATCH v2 1/1 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 <[email protected]>
---
 tools/lib/bpf/libbpf.c       | 2 ++
 tools/lib/bpf/libbpf_errno.c | 1 +
 2 files changed, 3 insertions(+)

Changelog:
v1 -> v2:
. undef _GNU_SOURCE instead of multiversioning strerror_r,
suggested by Jakub.

tools/lib/bpf/libbpf.c +2 -0
index ed4212a4c5f9..59b748ebd15f 100644
@@ -9,7 +9,9 @@
  * Copyright (C) 2017 Nicira, Inc.
  */
 
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
 #include <stdlib.h>
 #include <stdio.h>
 #include <stdarg.h>
tools/lib/bpf/libbpf_errno.c +1 -0
index d83b17f8435c..4343e40588c6 100644
@@ -7,6 +7,7 @@
  * Copyright (C) 2017 Nicira, Inc.
  */
 
+#undef _GNU_SOURCE
 #include <stdio.h>
 #include <string.h>
Signature · 1 line
2.17.1
Acked-by on v2 1/1
#1 lore raw
Quoted 12 lines · Yonghong Song

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);
Quoted 8 lines

...

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 <[email protected]>
Acked-by Jakub Kicinski <[email protected]>

FWIW :)

maintainer Applied
#2 lore raw
Quoted 20 lines · Jakub Kicinski
Quoted 19 lines · Yonghong Song

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.

Quoted 6 lines
Quoted 1 line
Signed-off-by Yonghong Song <[email protected]>
Acked-by Jakub Kicinski <[email protected]>

FWIW :)

Applied, thanks.