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