21 Jun
2017
21 Jun
'17
8:11 p.m.
Hi,
Thomas Petazzoni wrote,
Hello,
On Wed, 31 May 2017 23:41:26 +0000, Anthony G. Basile wrote:
As it seems to compile fine for glibc based toolchain, it is a
regression in uClibc-ng.
best regards
Waldemar
From: "Anthony G. Basile"
<blueness(a)gentoo.org>
man feature_test_macros(7) specifies that _BSD_SOURCE and _SVID_SOURCE have
been deprecated in favor of _DEFAULT_SOURCE since libc 2.20. Specifying
either of the former is now equivalent to specifying just the latter. We add
this macro to conform to this standard, but do not add the compiler warning
to maintain full backwards compatibility with earlier version of glibc and
uclibc.
Signed-off-by: Anthony G. Basile <blueness(a)gentoo.org>
This patch breaks the build of the "knock" package in Buildroot:
http://autobuild.buildroot.net/results/908/90863b5adb769a346acd3dc4bbe8d5fa…
src/knockd.c:1296:37: error: 'struct tcphdr' has no member named
'th_flags'
The tcphdr structure is defined in uClibc in two different ways,
depending on whether _FAVOR_BSD is defined or not. If _FAVOR_BSD is
defined, then the structure does have this th_flags member, otherwise
not.
_FAVOR_BSD is defined as follows:
#if defined _BSD_SOURCE && \
!(defined _POSIX_SOURCE || defined _POSIX_C_SOURCE || \
defined _XOPEN_SOURCE || defined _XOPEN_SOURCE_EXTENDED || \
defined _GNU_SOURCE || defined _SVID_SOURCE)
# define __FAVOR_BSD 1
#endif
When being built, the program passes both -D_BSD_SOURCE and
-D_DEFAULT_SOURCE. However, this patch has the effect that defining
_DEFAULT_SOURCE defines _SVID_SOURCE, which has the side effect of no
longer defining _FAVOR_BSD.
The definition of _DEFAULT_SOURCE is that it is equivalent to defining
_BSD_SOURCE and _SVID_SOURCE. However, it turns out that in the context
of uClibc, defining _SVID_SOURCE prevents __FAVOR_BSD from being
defined.
Where is the bug? In what the knock build system is doing, or in uClibc?