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: Few fixes for selftests/bpf built in release mode

Fix few issues found when building and running test_progs in
release mode.

First, potentially uninitialized idx variable in xskxceiver,
force-initialize to zero to satisfy compiler.

Few instances of defining uprobe trigger functions break in release mode
unless marked as noinline, due to being static. Add noinline to make
sure everything works.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/bpf/20220816001929.369487-5-andrii@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

selftests/bpf: fix uprobe offset calculation in selftests

Fix how selftests determine relative offset of a function that is
uprobed. Previously, there was an assumption that uprobed function is
always in the first executable region, which is not always the case
(libbpf CI hits this case now). So get_base_addr() approach in isolation
doesn't work anymore. So teach get_uprobe_offset() to determine correct
memory mapping and calculate uprobe offset correctly.

While at it, I merged together two implementations of
get_uprobe_offset() helper, moving powerpc64-specific logic inside (had
to add extra {} block to avoid unused variable error for insn).

Also ensured that uprobed functions are never inlined, but are still
static (and thus local to each selftest), by using a no-op asm volatile
block internally. I didn't want to keep them global __weak, because some
tests use uprobe's ref counter offset (to test USDT-like logic) which is
not compatible with non-refcounted uprobe. So it's nicer to have each
test uprobe target local to the file and guaranteed to not be inlined or
skipped by the compiler (which can happen with static functions,
especially if compiling selftests with -O2).

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220126193058.3390292-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Fix attach_probe in parallel mode

This patch makes attach_probe uses its own method as attach point,
avoiding conflict with other tests like bpf_cookie.

Signed-off-by: Yucong Sun <sunyucong@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211025223345.2136168-4-fallentree@fb.com

selftests/bpf: Adopt attach_probe selftest to work on old kernels

Make sure to not use ref_ctr_off feature when running on old kernels
that don't support this feature. This allows to test libbpf's legacy
kprobe and uprobe logic on old kernels.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210921210036.1545557-3-andrii@kernel.org

selftests/bpf: Add ref_ctr_offset selftests

Extend attach_probe selftests to specify ref_ctr_offset for uprobe/uretprobe
and validate that its value is incremented from zero.

Turns out that once uprobe is attached with ref_ctr_offset, uretprobe for the
same location/function *has* to use ref_ctr_offset as well, otherwise
perf_event_open() fails with -EINVAL. So this test uses ref_ctr_offset for
both uprobe and uretprobe, even though for the purpose of test uprobe would be
enough.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210815070609.987780-17-andrii@kernel.org

selftests/bpf: Extract uprobe-related helpers into trace_helpers.{c,h}

Extract two helpers used for working with uprobes into trace_helpers.{c,h} to
be re-used between multiple uprobe-using selftests. Also rename get_offset()
into more appropriate get_uprobe_offset().

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210815070609.987780-14-andrii@kernel.org

selftests/bpf: Turn on libbpf 1.0 mode and fix all IS_ERR checks

Turn ony libbpf 1.0 mode. Fix all the explicit IS_ERR checks that now will be
broken because libbpf returns NULL on error (and sets errno). Fix
ASSERT_OK_PTR and ASSERT_ERR_PTR to work for both old mode and new modes and
use them throughout selftests. This is trivial to do by using
libbpf_get_error() API that all libbpf users are supposed to use, instead of
IS_ERR checks.

A bunch of checks also did explicit -1 comparison for various fd-returning
APIs. Such checks are replaced with >= 0 or < 0 cases.

There were also few misuses of bpf_object__find_map_by_name() in test_maps.
Those are fixed in this patch as well.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210525035935.1461796-3-andrii@kernel.org

selftests/bpf: Fix test_attach_probe for powerpc uprobes

When testing uprobes we the test gets GEP (Global Entry Point)
address from kallsyms, but then the function is called locally
so the uprobe is not triggered.

Fixing this by adjusting the address to LEP (Local Entry Point)
for powerpc arch plus instruction check stolen from ppc_function_entry
function pointed out and explained by Michael and Naveen.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Link: https://lore.kernel.org/bpf/20210305134050.139840-1-jolsa@kernel.org

selftests/bpf: Fix test_attach_probe

Fix two issues in test_attach_probe:

1. it was not able to parse /proc/self/maps beyond the first line,
since %s means parse string until white space.
2. offset has to be accounted for otherwise uprobed address is incorrect.

Fixes: 1e8611bbdfc9 ("selftests/bpf: add kprobe/uprobe selftests")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191219020442.1922617-1-ast@kernel.org

bpftool, selftests/bpf: Embed object file inside skeleton

Embed contents of BPF object file used for BPF skeleton generation inside
skeleton itself. This allows to keep BPF object file and its skeleton in sync
at all times, and simpifies skeleton instantiation.

Also switch existing selftests to not require BPF_EMBED_OBJ anymore.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20191218052552.2915188-2-andriin@fb.com

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: Add BPF_EMBED_OBJ macro for embedding BPF .o files

Add a convenience macro BPF_EMBED_OBJ, which allows to embed other files
(typically used to embed BPF .o files) into a hosting userspace programs. To
C program it is exposed as struct bpf_embed_data, containing a pointer to
raw data and its size in bytes.

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/20191214014341.3442258-5-andriin@fb.com

libbpf: Make DECLARE_LIBBPF_OPTS macro strictly a variable declaration

LIBBPF_OPTS is implemented as a mix of field declaration and memset
+ assignment. This makes it neither variable declaration nor purely
statements, which is a problem, because you can't mix it with either
other variable declarations nor other function statements, because C90
compiler mode emits warning on mixing all that together.

This patch changes LIBBPF_OPTS into a strictly declaration of variable
and solves this problem, as can be seen in case of bpftool, which
previously would emit compiler warning, if done this way (LIBBPF_OPTS as
part of function variables declaration block).

This patch also renames LIBBPF_OPTS into DECLARE_LIBBPF_OPTS to follow
kernel convention for similar macros more closely.

v1->v2:
- rename LIBBPF_OPTS into DECLARE_LIBBPF_OPTS (Jakub Sitnicki).

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20191022172100.3281465-1-andriin@fb.com

selftest/bpf: Get rid of a bunch of explicit BPF program type setting

Now that libbpf can correctly guess BPF program types from section
names, remove a bunch of explicit bpf_program__set_type() calls
throughout tests.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191021033902.3856966-8-andriin@fb.com

selftests/bpf: switch tests to new bpf_object__open_{file, mem}() APIs

Verify new bpf_object__open_mem() and bpf_object__open_file() APIs work
as expected by switching test_attach_probe test to use embedded BPF
object and bpf_object__open_mem() and test_reference_tracking to
bpf_object__open_file().

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

selftests/bpf: fix perf_buffer on s390

perf_buffer test fails for exactly the same reason test_attach_probe
used to fail: different nanosleep syscall kprobe name.

Reuse the test_attach_probe fix.

Fixes: ee5cf82ce04a ("selftests/bpf: test perf buffer API")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: fix attach_probe on s390

attach_probe test fails, because it cannot install a kprobe on a
non-existent sys_nanosleep symbol.

Use the correct symbol name for the nanosleep syscall on 64-bit s390.
Don't bother adding one for 31-bit mode, since tests are compiled only
in 64-bit mode.

Fixes: 1e8611bbdfc9 ("selftests/bpf: add kprobe/uprobe selftests")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Acked-by: Andrii Nakryiko <andriin@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>