linux-stable/tools/testing/selftests/bpf/prog_tests/btf_endian.c
Daniel Müller afef88e655 selftests/bpf: Store BPF object files with .bpf.o extension
BPF object files are, in a way, the final artifact produced as part of
the ahead-of-time compilation process. That makes them somewhat special
compared to "regular" object files, which are a intermediate build
artifacts that can typically be removed safely. As such, it can make
sense to name them differently to make it easier to spot this difference
at a glance.

Among others, libbpf-bootstrap [0] has established the extension .bpf.o
for BPF object files. It seems reasonable to follow this example and
establish the same denomination for selftest build artifacts. To that
end, this change adjusts the corresponding part of the build system and
the test programs loading BPF object files to work with .bpf.o files.

  [0] https://github.com/libbpf/libbpf-bootstrap

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Müller <deso@posteo.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220901222253.1199242-1-deso@posteo.net
2022-09-02 15:55:37 +02:00

99 lines
3.2 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Facebook */
#define _GNU_SOURCE
#include <string.h>
#include <byteswap.h>
#include <test_progs.h>
#include <bpf/btf.h>
void test_btf_endian() {
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
enum btf_endianness endian = BTF_LITTLE_ENDIAN;
#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
enum btf_endianness endian = BTF_BIG_ENDIAN;
#else
#error "Unrecognized __BYTE_ORDER__"
#endif
enum btf_endianness swap_endian = 1 - endian;
struct btf *btf = NULL, *swap_btf = NULL;
const void *raw_data, *swap_raw_data;
const struct btf_type *t;
const struct btf_header *hdr;
__u32 raw_sz, swap_raw_sz;
int var_id;
/* Load BTF in native endianness */
btf = btf__parse_elf("btf_dump_test_case_syntax.bpf.o", NULL);
if (!ASSERT_OK_PTR(btf, "parse_native_btf"))
goto err_out;
ASSERT_EQ(btf__endianness(btf), endian, "endian");
btf__set_endianness(btf, swap_endian);
ASSERT_EQ(btf__endianness(btf), swap_endian, "endian");
/* Get raw BTF data in non-native endianness... */
raw_data = btf__raw_data(btf, &raw_sz);
if (!ASSERT_OK_PTR(raw_data, "raw_data_inverted"))
goto err_out;
/* ...and open it as a new BTF instance */
swap_btf = btf__new(raw_data, raw_sz);
if (!ASSERT_OK_PTR(swap_btf, "parse_swap_btf"))
goto err_out;
ASSERT_EQ(btf__endianness(swap_btf), swap_endian, "endian");
ASSERT_EQ(btf__type_cnt(swap_btf), btf__type_cnt(btf), "nr_types");
swap_raw_data = btf__raw_data(swap_btf, &swap_raw_sz);
if (!ASSERT_OK_PTR(swap_raw_data, "swap_raw_data"))
goto err_out;
/* both raw data should be identical (with non-native endianness) */
ASSERT_OK(memcmp(raw_data, swap_raw_data, raw_sz), "mem_identical");
/* make sure that at least BTF header data is really swapped */
hdr = swap_raw_data;
ASSERT_EQ(bswap_16(hdr->magic), BTF_MAGIC, "btf_magic_swapped");
ASSERT_EQ(raw_sz, swap_raw_sz, "raw_sizes");
/* swap it back to native endianness */
btf__set_endianness(swap_btf, endian);
swap_raw_data = btf__raw_data(swap_btf, &swap_raw_sz);
if (!ASSERT_OK_PTR(swap_raw_data, "swap_raw_data"))
goto err_out;
/* now header should have native BTF_MAGIC */
hdr = swap_raw_data;
ASSERT_EQ(hdr->magic, BTF_MAGIC, "btf_magic_native");
ASSERT_EQ(raw_sz, swap_raw_sz, "raw_sizes");
/* now modify original BTF */
var_id = btf__add_var(btf, "some_var", BTF_VAR_GLOBAL_ALLOCATED, 1);
ASSERT_GT(var_id, 0, "var_id");
btf__free(swap_btf);
swap_btf = NULL;
btf__set_endianness(btf, swap_endian);
raw_data = btf__raw_data(btf, &raw_sz);
if (!ASSERT_OK_PTR(raw_data, "raw_data_inverted"))
goto err_out;
/* and re-open swapped raw data again */
swap_btf = btf__new(raw_data, raw_sz);
if (!ASSERT_OK_PTR(swap_btf, "parse_swap_btf"))
goto err_out;
ASSERT_EQ(btf__endianness(swap_btf), swap_endian, "endian");
ASSERT_EQ(btf__type_cnt(swap_btf), btf__type_cnt(btf), "nr_types");
/* the type should appear as if it was stored in native endianness */
t = btf__type_by_id(swap_btf, var_id);
ASSERT_STREQ(btf__str_by_offset(swap_btf, t->name_off), "some_var", "var_name");
ASSERT_EQ(btf_var(t)->linkage, BTF_VAR_GLOBAL_ALLOCATED, "var_linkage");
ASSERT_EQ(t->type, 1, "var_type");
err_out:
btf__free(btf);
btf__free(swap_btf);
}