On Thu, Aug 25, 2022 at 11:49 PM Martin KaFai Lau kafai@fb.com wrote:
On Thu, Aug 25, 2022 at 11:31:15PM -0600, James Hilliard wrote:
On Thu, Aug 25, 2022 at 11:16 PM Martin KaFai Lau kafai@fb.com wrote:
On Thu, Aug 25, 2022 at 04:17:49PM -0600, James Hilliard wrote:
There is a potential for us to hit a type conflict when including netinet/tcp.h with sys/socket.h, we can replace both of these includes with linux/tcp.h to avoid this conflict.
Fixes errors like: In file included from /usr/include/netinet/tcp.h:91, from progs/bind4_prog.c:10: /home/buildroot/opt/cross/lib/gcc/bpf/13.0.0/include/stdint.h:34:23: error: conflicting types for 'int8_t'; have 'char' 34 | typedef __INT8_TYPE__ int8_t; | ^~~~~~ In file included from /usr/include/x86_64-linux-gnu/sys/types.h:155, from /usr/include/x86_64-linux-gnu/bits/socket.h:29, from /usr/include/x86_64-linux-gnu/sys/socket.h:33, from progs/bind4_prog.c:9: /usr/include/x86_64-linux-gnu/bits/stdint-intn.h:24:18: note: previous declaration of 'int8_t' with type 'int8_t' {aka 'signed char'} 24 | typedef __int8_t int8_t; | ^~~~~~ /home/buildroot/opt/cross/lib/gcc/bpf/13.0.0/include/stdint.h:43:24: error: conflicting types for 'int64_t'; have 'long int' 43 | typedef __INT64_TYPE__ int64_t; | ^~~~~~~ /usr/include/x86_64-linux-gnu/bits/stdint-intn.h:27:19: note: previous declaration of 'int64_t' with type 'int64_t' {aka 'long long int'} 27 | typedef __int64_t int64_t; | ^~~~~~~ make: *** [Makefile:537: /home/buildroot/bpf-next/tools/testing/selftests/bpf/bpf_gcc/bind4_prog.o] Error 1
Signed-off-by: James Hilliard james.hilliard1@gmail.com
tools/testing/selftests/bpf/progs/bind4_prog.c | 3 +-- tools/testing/selftests/bpf/progs/bind6_prog.c | 3 +-- 2 files changed, 2 insertions(+), 4 deletions(-)
diff --git a/tools/testing/selftests/bpf/progs/bind4_prog.c b/tools/testing/selftests/bpf/progs/bind4_prog.c index 474c6a62078a..6bd20042fd53 100644 --- a/tools/testing/selftests/bpf/progs/bind4_prog.c +++ b/tools/testing/selftests/bpf/progs/bind4_prog.c @@ -6,8 +6,7 @@ #include <linux/bpf.h> #include <linux/in.h> #include <linux/in6.h> -#include <sys/socket.h> -#include <netinet/tcp.h>
These includes look normal to me. What environment is hitting this.
I was hitting this error with GCC 13(GCC master branch).
These two includes (<sys/socket.h> and <netinet/tcp.h>) are normal, so does it mean all existing programs need to change to use gcc 13 ?
Well I think it's mostly just an issue getting hit with GCC-BPF as it looks to me like a cross compilation host/target header conflict.
This is an interesting issue.
Right now the BPF GCC target is a sort of a bare-metal target. As such, it provides a set of header files that implement ISO C types and other machinery (i.e. it doesn't rely on a C library to provide them):
iso646.h stdalign.h stdarg.h stdatomic.h stdbool.h stddef.h stdfix.h stdint.h stdnoreturn.h tgmath.h unwind.h varargs.h
This is because we were expecting this to be used like:
<compiler-provided std C headers> | | v | <kernel headers> | | | v v <BPF C program>
However, if it is expected/intended for C BPF programs to include libc headers, such as sys/socket.h, this can quickly go sour as you have found with that conflict.
So this leads to the question: should we turn the BPF target into a target that assumes a libc? This basically means we will be assuming BPF programs are always compiled in an environment that provides a standard stdint.h, stdbool.h and friends.
Thoughts?
I don't prefer the selftest writers need to remember this rule.
Beside, afaict, tcp.h should be removed because I don't see this test needs it. I tried removing it and it works fine. It should be removed instead of replacing it with another unnecessary tcp.h.
Oh, that does also appear to work, thought I had tried that already but I guess I hadn't, sent a v2 with them removed: https://lore.kernel.org/bpf/20220826052925.980431-1-james.hilliard1@gmail.co...
+#include <linux/tcp.h> #include <linux/if.h> #include <errno.h>
diff --git a/tools/testing/selftests/bpf/progs/bind6_prog.c b/tools/testing/selftests/bpf/progs/bind6_prog.c index c19cfa869f30..f37617b35a55 100644 --- a/tools/testing/selftests/bpf/progs/bind6_prog.c +++ b/tools/testing/selftests/bpf/progs/bind6_prog.c @@ -6,8 +6,7 @@ #include <linux/bpf.h> #include <linux/in.h> #include <linux/in6.h> -#include <sys/socket.h> -#include <netinet/tcp.h> +#include <linux/tcp.h> #include <linux/if.h> #include <errno.h>
-- 2.34.1