selftests/bpf: Add test for legacy/perf kprobe/uprobe attach mode

Add the testing for kprobe/uprobe attaching in default, legacy, perf and
link mode. And the testing passed:

./test_progs -t attach_probe
$5/1 attach_probe/manual-default:OK
$5/2 attach_probe/manual-legacy:OK
$5/3 attach_probe/manual-perf:OK
$5/4 attach_probe/manual-link:OK
$5/5 attach_probe/auto:OK
$5/6 attach_probe/kprobe-sleepable:OK
$5/7 attach_probe/uprobe-lib:OK
$5/8 attach_probe/uprobe-sleepable:OK
$5/9 attach_probe/uprobe-ref_ctr:OK
$5 attach_probe:OK
Summary: 1/9 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Menglong Dong <imagedong@tencent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Biao Jiang <benbjiang@tencent.com>
Link: https://lore.kernel.org/bpf/20230306064833.7932-4-imagedong@tencent.com

selftests/bpf: Split test_attach_probe into multi subtests

In order to adapt to the older kernel, now we split the "attach_probe"
testing into multi subtests:

manual // manual attach tests for kprobe/uprobe
auto // auto-attach tests for kprobe and uprobe
kprobe-sleepable // kprobe sleepable test
uprobe-lib // uprobe tests for library function by name
uprobe-sleepable // uprobe sleepable test
uprobe-ref_ctr // uprobe ref_ctr test

As sleepable kprobe needs to set BPF_F_SLEEPABLE flag before loading,
we need to move it to a stand alone skel file, in case of it is not
supported by kernel and make the whole loading fail.

Therefore, we can only enable part of the subtests for older kernel.

Signed-off-by: Menglong Dong <imagedong@tencent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Biao Jiang <benbjiang@tencent.com>
Link: https://lore.kernel.org/bpf/20230306064833.7932-3-imagedong@tencent.com

selftests/bpf: Attach to fopen()/fclose() in attach_probe

malloc() and free() may be completely replaced by sanitizers, use
fopen() and fclose() instead.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230210001210.395194-7-iii@linux.ibm.com

selftests/bpf: use BPF_KSYSCALL and SEC("ksyscall") in selftests

Convert few selftest that used plain SEC("kprobe") with arch-specific
syscall wrapper prefix to ksyscall/kretsyscall and corresponding
BPF_KSYSCALL macro. test_probe_user.c is especially benefiting from this
simplification.

Tested-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220714070755.3235561-6-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: add tests for sleepable (uk)probes

Add tests that ensure sleepable uprobe programs work correctly.
Add tests that ensure sleepable kprobe programs cannot attach.

Also add tests that attach both sleepable and non-sleepable
uprobe programs to the same location (i.e. same bpf_prog_array).

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Delyan Kratunov <delyank@fb.com>
Link: https://lore.kernel.org/r/c744e5bb7a5c0703f05444dc41f2522ba3579a48.1655248076.git.delyank@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Use target-less SEC() definitions in various tests

Add new or modify existing SEC() definitions to be target-less and
validate that libbpf handles such program definitions correctly.

For kprobe/kretprobe we also add explicit test that generic
bpf_program__attach() works in cases when kprobe definition contains
proper target. It wasn't previously tested as selftests code always
explicitly specified the target regardless.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20220428185349.3799599-4-andrii@kernel.org

selftests/bpf: Add tests for u[ret]probe attach by name

add tests that verify attaching by name for

1. local functions in a program
2. library functions in a shared object

...succeed for uprobe and uretprobes using new "func_name"
option for bpf_program__attach_uprobe_opts(). Also verify
auto-attach works where uprobe, path to binary and function
name are specified, but fails with -EOPNOTSUPP with a SEC
name that does not specify binary path/function.

Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1648654000-21758-5-git-send-email-alan.maguire@oracle.com

libbpf: Merge selftests' bpf_trace_helpers.h into libbpf's bpf_tracing.h

Move BPF_PROG, BPF_KPROBE, and BPF_KRETPROBE macro into libbpf's bpf_tracing.h
header to make it available for non-selftests users.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200229231112.1240137-5-andriin@fb.com

selftests/bpf: Fix BPF_KRETPROBE macro and use it in attach_probe test

For kretprobes, there is no point in capturing input arguments from pt_regs,
as they are going to be, most probably, clobbered by the time probed kernel
function returns. So switch BPF_KRETPROBE to accept zero or one argument
(optional return result).

Fixes: ac065870d928 ("selftests/bpf: Add BPF_PROG, BPF_KPROBE, and BPF_KRETPROBE macros")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200229231112.1240137-4-andriin@fb.com

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 <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/157952560568.1683545.9649335788846513446.stgit@toke.dk

selftests/bpf: Add BPF skeletons selftests and convert attach_probe.c

Add BPF skeleton generation to selftest/bpf's Makefile. Convert attach_probe.c
to use skeleton.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191214014341.3442258-15-andriin@fb.com

libbpf: stop enforcing kern_version, populate it for users

Kernel version enforcement for kprobes/kretprobes was removed from
5.0 kernel in 6c4fc209fcf9 ("bpf: remove useless version check for prog load").
Since then, BPF programs were specifying SEC("version") just to please
libbpf. We should stop enforcing this in libbpf, if even kernel doesn't
care. Furthermore, libbpf now will pre-populate current kernel version
of the host system, in case we are still running on old kernel.

This patch also removes __bpf_object__open_xattr from libbpf.h, as
nothing in libbpf is relying on having it in that header. That function
was never exported as LIBBPF_API and even name suggests its internal
version. So this should be safe to remove, as it doesn't break ABI.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: fix test_attach_probe map definition

ef99b02b23ef ("libbpf: capture value in BTF type info for BTF-defined map
defs") changed BTF-defined maps syntax, while independently merged
1e8611bbdfc9 ("selftests/bpf: add kprobe/uprobe selftests") added new
test using outdated syntax of maps. This patch fixes this test after
corresponding patch sets were merged.

Fixes: ef99b02b23ef ("libbpf: capture value in BTF type info for BTF-defined map defs")
Fixes: 1e8611bbdfc9 ("selftests/bpf: add kprobe/uprobe selftests")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

selftests/bpf: add kprobe/uprobe selftests

Add tests verifying kprobe/kretprobe/uprobe/uretprobe APIs work as
expected.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>