selftests/bpf: Fix C++ compile error from missing _Bool type

While building, bpftool makes a skeleton from test_core_extern.c, which
itself includes <stdbool.h> and uses the 'bool' type. However, th

selftests/bpf: Fix C++ compile error from missing _Bool type

While building, bpftool makes a skeleton from test_core_extern.c, which
itself includes <stdbool.h> and uses the 'bool' type. However, the skeleton
test_core_extern.skel.h generated *does not* include <stdbool.h> or use the
'bool' type, instead using the C-only '_Bool' type. Compiling test_cpp.cpp
with g++ 12.3 for mips64el/musl-libc then fails with error:

In file included from test_cpp.cpp:9:
test_core_extern.skel.h:45:17: error: '_Bool' does not name a type
45 | _Bool CONFIG_BOOL;
| ^~~~~

This was likely missed previously because glibc uses a GNU extension for
<stdbool.h> with C++ (#define _Bool bool), not supported by musl libc.

Normally, a C fragment would include <stdbool.h> and use the 'bool' type,
and thus cleanly work after import by C++. The ideal fix would be for
'bpftool gen skeleton' to output the correct type/include supporting C++,
but in the meantime add a conditional define as above.

Fixes: 7c8dce4b1661 ("bpftool: Make skeleton C code compilable with C++ compiler")
Signed-off-by: Tony Ambardar <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/bpf/6fc1dd28b8bda49e51e4f610bdc9d22f4455632d.1722244708.git.tony.ambardar@gmail.com

show more ...

bpftool: Cast pointers for shadow types explicitly.

According to a report, skeletons fail to assign shadow pointers when being
compiled with C++ programs. Unlike C doing implicit casting for void
po

bpftool: Cast pointers for shadow types explicitly.

According to a report, skeletons fail to assign shadow pointers when being
compiled with C++ programs. Unlike C doing implicit casting for void
pointers, C++ requires an explicit casting.

To support C++, we do explicit casting for each shadow pointer.

Also add struct_ops_module.skel.h to test_cpp to validate C++
compilation as part of BPF selftests.

Signed-off-by: Kui-Feng Lee <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Acked-by: Yonghong Song <[email protected]>
Acked-by: Quentin Monnet <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

show more ...

Fix typos in selftest/bpf files

Run spell checker on files in selftest/bpf and fixed typos.

Signed-off-by: Taichi Nishimura <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>

Fix typos in selftest/bpf files

Run spell checker on files in selftest/bpf and fixed typos.

Signed-off-by: Taichi Nishimura <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Reviewed-by: Randy Dunlap <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

show more ...

selftests/bpf: Make sure enum-less bpf_enable_stats() API works in C++ mode

Just a simple test to make sure we don't introduce unwanted compiler
warnings and API still supports passing enums as inpu

selftests/bpf: Make sure enum-less bpf_enable_stats() API works in C++ mode

Just a simple test to make sure we don't introduce unwanted compiler
warnings and API still supports passing enums as input argument.

Signed-off-by: Andrii Nakryiko <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

show more ...

selftests/bpf: Fix a clang deprecated-declarations compilation error

Build the kernel and selftest with clang compiler with LLVM=1,
make -j LLVM=1
make -C tools/testing/selftests/bpf -j LLVM=1

selftests/bpf: Fix a clang deprecated-declarations compilation error

Build the kernel and selftest with clang compiler with LLVM=1,
make -j LLVM=1
make -C tools/testing/selftests/bpf -j LLVM=1

I hit the following selftests/bpf compilation error:
In file included from test_cpp.cpp:3:
/.../tools/testing/selftests/bpf/tools/include/bpf/libbpf.h:73:8:
error: 'relaxed_core_relocs' is deprecated: libbpf v0.6+: field has no effect [-Werror,-Wdeprecated-declarations]
struct bpf_object_open_opts {
^
test_cpp.cpp:56:2: note: in implicit move constructor for 'bpf_object_open_opts' first required here
LIBBPF_OPTS(bpf_object_open_opts, opts);
^
/.../tools/testing/selftests/bpf/tools/include/bpf/libbpf_common.h:77:3: note: expanded from macro 'LIBBPF_OPTS'
(struct TYPE) { \
^
/.../tools/testing/selftests/bpf/tools/include/bpf/libbpf.h:90:2: note: 'relaxed_core_relocs' has been explicitly marked deprecated here
LIBBPF_DEPRECATED_SINCE(0, 6, "field has no effect")
^
/.../tools/testing/selftests/bpf/tools/include/bpf/libbpf_common.h:24:4: note: expanded from macro 'LIBBPF_DEPRECATED_SINCE'
(LIBBPF_DEPRECATED("libbpf v" # major "." # minor "+: " msg))
^
/.../tools/testing/selftests/bpf/tools/include/bpf/libbpf_common.h:19:47: note: expanded from macro 'LIBBPF_DEPRECATED'
#define LIBBPF_DEPRECATED(msg) __attribute__((deprecated(msg)))

There are two ways to fix the issue, one is to use GCC diagnostic ignore pragma, and the
other is to open code bpf_object_open_opts instead of using LIBBPF_OPTS.
Since in general LIBBPF_OPTS is preferred, the patch fixed the issue by
adding proper GCC diagnostic ignore pragmas.

Signed-off-by: Yonghong Song <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

show more ...

selftests/bpf: Add Skeleton templated wrapper as an example

Add an example of how to build C++ template-based BPF skeleton wrapper.
It's an actually runnable valid use of skeleton through more C++-l

selftests/bpf: Add Skeleton templated wrapper as an example

Add an example of how to build C++ template-based BPF skeleton wrapper.
It's an actually runnable valid use of skeleton through more C++-like
interface. Note that skeleton destuction happens implicitly through
Skeleton<T>'s destructor.

Also make test_cpp runnable as it would have crashed on invalid btf
passed into btf_dump__new().

Signed-off-by: Andrii Nakryiko <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

show more ...

selftests/bpf: Add btf_dump__new to test_cpp

Adding btf_dump__new call to test_cpp, so we can
test C++ compilation with that.

Signed-off-by: Jiri Olsa <[email protected]>
Signed-off-by: Andrii Nakry

selftests/bpf: Add btf_dump__new to test_cpp

Adding btf_dump__new call to test_cpp, so we can
test C++ compilation with that.

Signed-off-by: Jiri Olsa <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Acked-by: Yonghong Song <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

show more ...

selftests: Use consistent include paths for libbpf

Fix all selftests to include libbpf header files with the bpf/ prefix, to
be consistent with external users of the library. Also ensure that all
in

selftests: Use consistent include paths for libbpf

Fix all selftests to include libbpf header files with the bpf/ prefix, to
be consistent with external users of the library. Also ensure that all
includes of exported libbpf header files (those that are exported on 'make
install' of the library) use bracketed includes instead of quoted.

To not break the build, keep the old include path until everything has been
changed to the new one; a subsequent patch will remove that.

Fixes: 6910d7d3867a ("selftests/bpf: Ensure bpf_helper_defs.h are taken from selftests dir")
Signed-off-by: Toke Høiland-Jørgensen <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Acked-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

show more ...

bpftool: Make skeleton C code compilable with C++ compiler

When auto-generated BPF skeleton C code is included from C++ application, it
triggers compilation error due to void * being implicitly cast

bpftool: Make skeleton C code compilable with C++ compiler

When auto-generated BPF skeleton C code is included from C++ application, it
triggers compilation error due to void * being implicitly casted to whatever
target pointer type. This is supported by C, but not C++. To solve this
problem, add explicit casts, where necessary.

To ensure issues like this are captured going forward, add skeleton usage in
test_cpp test.

Signed-off-by: Andrii Nakryiko <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

show more ...

selftests/bpf: Bring back c++ include/link test

Commit 5c26f9a78358 ("libbpf: Don't use cxx to test_libpf target")
converted existing c++ test to c. We still want to include and
link against libbpf

selftests/bpf: Bring back c++ include/link test

Commit 5c26f9a78358 ("libbpf: Don't use cxx to test_libpf target")
converted existing c++ test to c. We still want to include and
link against libbpf from c++ code, so reinstate this test back,
this time in a form of a selftest with a clear comment about
its purpose.

v2:
* -lelf -> $(LDLIBS) (Andrii Nakryiko)

Fixes: 5c26f9a78358 ("libbpf: Don't use cxx to test_libpf target")
Signed-off-by: Stanislav Fomichev <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Acked-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

show more ...