selftests/bpf: Add test involving restrict type qualifier

This change adds a type based test involving the restrict type qualifier
to the BPF selftests. On the btfgen path, this will verify that bpftool
correctly handles the corresponding RESTRICT BTF kind.

Signed-off-by: Daniel Müller <deso@posteo.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20220706212855.1700615-3-deso@posteo.net

selftests/bpf: Add type match test against kernel's task_struct

This change extends the existing core_reloc/kernel test to include a
type match check of a local task_struct against the kernel's definition
-- which we assume to succeed.

Signed-off-by: Daniel Müller <deso@posteo.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220628160127.607834-11-deso@posteo.net

selftests/bpf: Add nested type to type based tests

This change extends the type based tests with another struct type (in
addition to a_struct) to check relocations against: a_complex_struct.
This type is nested more deeply to provide additional coverage of
certain paths in the type match logic.

Signed-off-by: Daniel Müller <deso@posteo.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220628160127.607834-10-deso@posteo.net

selftests/bpf: Add test checking more characteristics

This change adds another type-based self-test that specifically aims to
test some more characteristics of the TYPE_MATCH logic. Specifically, it
covers a few more potential differences between types, such as different
orders, enum variant values, and integer signedness.

Signed-off-by: Daniel Müller <deso@posteo.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220628160127.607834-9-deso@posteo.net

selftests/bpf: Add type-match checks to type-based tests

Now that we have type-match logic in both libbpf and the kernel, this
change adjusts the existing BPF self tests to check this functionality.
Specifically, we extend the existing type-based tests to check the
previously introduced bpf_core_type_matches macro.

Signed-off-by: Daniel Müller <deso@posteo.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220628160127.607834-8-deso@posteo.net

selftests/bpf: Add a test for enum64 value relocations

Add a test for enum64 value relocations.
The test will be skipped if clang version is 14 or lower
since enum64 is only supported from version 15.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220607062718.3726307-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Add bpf_core_field_offset() tests

Add test cases for bpf_core_field_offset() helper.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220509004148.1801791-7-andrii@kernel.org

selftests/bpf: Fix field existence CO-RE reloc tests

Negative field existence cases for have a broken assumption that FIELD_EXISTS
CO-RE relo will fail for fields that match the name but have incompatible type
signature. That's not how CO-RE relocations generally behave. Types and fields
that match by name but not by expected type are treated as non-matching
candidates and are skipped. Error later is reported if no matching candidate
was found. That's what happens for most relocations, but existence relocations
(FIELD_EXISTS and TYPE_EXISTS) are more permissive and they are designed to
return 0 or 1, depending if a match is found. This allows to handle
name-conflicting but incompatible types in BPF code easily. Combined with
___flavor suffixes, it's possible to handle pretty much any structural type
changes in kernel within the compiled once BPF source code.

So, long story short, negative field existence test cases are invalid in their
assumptions, so this patch reworks them into a single consolidated positive
case that doesn't match any of the fields.

Fixes: c7566a69695c ("selftests/bpf: Add field existence CO-RE relocs tests")
Reported-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Lorenz Bauer <lmb@cloudflare.com>
Link: https://lore.kernel.org/bpf/20210426192949.416837-5-andrii@kernel.org

selftests/bpf: Add BTF_KIND_FLOAT to test_core_reloc_size

Verify that bpf_core_field_size() is working correctly with floats.
Also document the required clang version.

Suggested-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210309005649.162480-2-iii@linux.ibm.com

selftests/bpf: Add CO-RE relocs selftest relying on kernel module BTF

Add a self-tests validating libbpf is able to perform CO-RE relocations
against the type defined in kernel module BTF. if bpf_testmod.o is not
supported by the kernel (e.g., due to version mismatch), skip tests, instead
of failing.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201203204634.1325171-9-andrii@kernel.org

selftests/bpf: Add tests for ENUMVAL_EXISTS/ENUMVAL_VALUE relocations

Add tests validating existence and value relocations for enum value-based
relocations. If __builtin_preserve_enum_value() built-in is not supported,
skip tests.

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/20200819194519.3375898-6-andriin@fb.com

selftests/bpf: Add CO-RE relo test for TYPE_ID_LOCAL/TYPE_ID_TARGET

Add tests for BTF type ID relocations. To allow testing this, enhance
core_relo.c test runner to allow dynamic initialization of test inputs.
If Clang doesn't have necessary support for new functionality, test is
skipped.

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/20200819194519.3375898-4-andriin@fb.com

selftests/bpf: Test TYPE_EXISTS and TYPE_SIZE CO-RE relocations

Add selftests for TYPE_EXISTS and TYPE_SIZE relocations, testing correctness
of relocations and handling of type compatiblity/incompatibility.

If __builtin_preserve_type_info() is not supported by compiler, skip tests.

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/20200819194519.3375898-3-andriin@fb.com

selftests/bpf: Add test validating failure on ambiguous relocation value

Add test simulating ambiguous field size relocation, while fields themselves
are at the exact same offset.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200818223921.2911963-5-andriin@fb.com

selftests/bpf: Correct various core_reloc 64-bit assumptions

Ensure that types are memory layout- and field alignment-compatible regardless
of 32/64-bitness mix of libbpf and BPF architecture.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200813204945.1020225-8-andriin@fb.com

bpf, libbpf: Replace zero-length array with flexible-array

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
int stuff;
struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200507185057.GA13981@embeddedor

selftests/bpf: Add flexible array relocation tests

Add few tests validation CO-RE relocation handling of flexible array accesses.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191215070844.1014385-3-andriin@fb.com

selftests/bpf: Add field size relocation tests

Add test verifying correctness and logic of field size relocation support in
libbpf.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191101222810.1246166-6-andriin@fb.com

selftest/bpf: Add relocatable bitfield reading tests

Add a bunch of selftests verifying correctness of relocatable bitfield reading
support in libbpf. Both bpf_probe_read()-based and direct read-based bitfield
macros are tested. core_reloc.c "test_harness" is extended to support raw
tracepoint and new typed raw tracepoints as test BPF program types.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191101222810.1246166-5-andriin@fb.com

selftests/bpf: Remove too strict field offset relo test cases

As libbpf is going to gain support for more field relocations, including field
size, some restrictions about exact size match are going to be lifted. Remove
test cases that explicitly test such failures.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191101222810.1246166-2-andriin@fb.com

selftests/bpf: Make CO-RE reloc test impartial to test_progs flavor

test_core_reloc_kernel test captures its own process name and validates
it as part of the test. Given extra "flavors" of test_progs, this break
for anything by default test_progs binary. Fix the test to cut out
flavor part of the process name.

Fixes: ee2eb063d330 ("selftests/bpf: Add BPF_CORE_READ and BPF_CORE_READ_STR_INTO macro tests")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191016060051.2024182-3-andriin@fb.com

selftests/bpf: Add field existence CO-RE relocs tests

Add a bunch of tests validating CO-RE is handling field existence
relocation. Relaxed CO-RE relocation mode is activated for these new
tests to prevent libbpf from rejecting BPF object for no-match
relocation, even though test BPF program is not going to use that
relocation, if field is missing.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191015182849.3922287-6-andriin@fb.com

selftests/bpf: Add BPF_CORE_READ and BPF_CORE_READ_STR_INTO macro tests

Validate BPF_CORE_READ correctness and handling of up to 9 levels of
nestedness using cyclic task->(group_leader->)*->tgid chains.

Also add a test of maximum-dpeth BPF_CORE_READ_STR_INTO() macro.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20191008175942.1769476-8-andriin@fb.com

tools/bpf: fix core_reloc.c compilation error

On my local machine, I have the following compilation errors:
=====
In file included from prog_tests/core_reloc.c:3:0:
./progs/core_reloc_types.h:517:46: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘fancy_char_ptr_t’
typedef const char * const volatile restrict fancy_char_ptr_t;
^
./progs/core_reloc_types.h:527:2: error: unknown type name ‘fancy_char_ptr_t’
fancy_char_ptr_t d;
^
=====

I am using gcc 4.8.5. Later compilers may change their behavior not emitting the
error. Nevertheless, let us fix the issue. "restrict" can be tested
without typedef.

Fixes: 9654e2ae908e ("selftests/bpf: add CO-RE relocs modifiers/typedef tests")
Cc: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: add CO-RE relocs misc tests

Add tests validating few edge-cases of capturing offset relocations.

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

selftests/bpf: add CO-RE relocs ints tests

Add various tests validating handling compatible/incompatible integer
types.

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

selftests/bpf: add CO-RE relocs ptr-as-array tests

Add test validating correct relocation handling for cases where pointer
to something is used as an array. E.g.:

int *ptr = ...;
int x = ptr[42];

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

selftests/bpf: add CO-RE relocs modifiers/typedef tests

Add tests validating correct handling of various combinations of
typedefs and const/volatile/restrict modifiers.

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

selftests/bpf: add CO-RE relocs enum/ptr/func_proto tests

Test CO-RE relocation handling of ints, enums, pointers, func protos, etc.

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

selftests/bpf: add CO-RE relocs array tests

Add tests for various array handling/relocation scenarios.

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

selftests/bpf: add CO-RE relocs nesting tests

Add a bunch of test validating correct handling of nested
structs/unions.

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

selftests/bpf: add CO-RE relocs struct flavors tests

Add tests verifying that BPF program can use various struct/union
"flavors" to extract data from the same target struct/union.

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