Commit 1306c980 authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Alexei Starovoitov
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selftests/bpf: Add checking of raw type dump in BTF writer APIs selftests 



Add re-usable btf_helpers.{c,h} to provide BTF-related testing routines. Start
with adding a raw BTF dumping helpers.

Raw BTF dump is the most succinct and at the same time a very human-friendly
way to validate exact contents of BTF types. Cross-validate raw BTF dump and
writable BTF in a single selftest. Raw type dump checks also serve as a good
self-documentation.

Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarSong Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20201105043402.2530976-7-andrii@kernel.org
parent 197389da

tools/testing/selftests/bpf/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -386,7 +386,7 @@ TRUNNER_TESTS_DIR := prog_tests 
TRUNNER_BPF_PROGS_DIR := progs

TRUNNER_EXTRA_SOURCES := test_progs.c cgroup_helpers.c trace_helpers.c	\

			 network_helpers.c testing_helpers.c		\

			 flow_dissector_load.h

			 btf_helpers.c	flow_dissector_load.h

TRUNNER_EXTRA_FILES := $(OUTPUT)/urandom_read				\

		       $(wildcard progs/btf_dump_test_case_*.c)

TRUNNER_BPF_BUILD_RULE := CLANG_BPF_BUILD_RULE

tools/testing/selftests/bpf/btf_helpers.c

0 → 100644
+200 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2020 Facebook */

#include <stdio.h>

#include <errno.h>

#include <bpf/btf.h>



static const char * const btf_kind_str_mapping[] = {

	[BTF_KIND_UNKN]		= "UNKNOWN",

	[BTF_KIND_INT]		= "INT",

	[BTF_KIND_PTR]		= "PTR",

	[BTF_KIND_ARRAY]	= "ARRAY",

	[BTF_KIND_STRUCT]	= "STRUCT",

	[BTF_KIND_UNION]	= "UNION",

	[BTF_KIND_ENUM]		= "ENUM",

	[BTF_KIND_FWD]		= "FWD",

	[BTF_KIND_TYPEDEF]	= "TYPEDEF",

	[BTF_KIND_VOLATILE]	= "VOLATILE",

	[BTF_KIND_CONST]	= "CONST",

	[BTF_KIND_RESTRICT]	= "RESTRICT",

	[BTF_KIND_FUNC]		= "FUNC",

	[BTF_KIND_FUNC_PROTO]	= "FUNC_PROTO",

	[BTF_KIND_VAR]		= "VAR",

	[BTF_KIND_DATASEC]	= "DATASEC",

};



static const char *btf_kind_str(__u16 kind)

{

	if (kind > BTF_KIND_DATASEC)

		return "UNKNOWN";

	return btf_kind_str_mapping[kind];

}



static const char *btf_int_enc_str(__u8 encoding)

{

	switch (encoding) {

	case 0:

		return "(none)";

	case BTF_INT_SIGNED:

		return "SIGNED";

	case BTF_INT_CHAR:

		return "CHAR";

	case BTF_INT_BOOL:

		return "BOOL";

	default:

		return "UNKN";

	}

}



static const char *btf_var_linkage_str(__u32 linkage)

{

	switch (linkage) {

	case BTF_VAR_STATIC:

		return "static";

	case BTF_VAR_GLOBAL_ALLOCATED:

		return "global-alloc";

	default:

		return "(unknown)";

	}

}



static const char *btf_func_linkage_str(const struct btf_type *t)

{

	switch (btf_vlen(t)) {

	case BTF_FUNC_STATIC:

		return "static";

	case BTF_FUNC_GLOBAL:

		return "global";

	case BTF_FUNC_EXTERN:

		return "extern";

	default:

		return "(unknown)";

	}

}



static const char *btf_str(const struct btf *btf, __u32 off)

{

	if (!off)

		return "(anon)";

	return btf__str_by_offset(btf, off) ?: "(invalid)";

}



int fprintf_btf_type_raw(FILE *out, const struct btf *btf, __u32 id)

{

	const struct btf_type *t;

	int kind, i;

	__u32 vlen;



	t = btf__type_by_id(btf, id);

	if (!t)

		return -EINVAL;



	vlen = btf_vlen(t);

	kind = btf_kind(t);



	fprintf(out, "[%u] %s '%s'", id, btf_kind_str(kind), btf_str(btf, t->name_off));



	switch (kind) {

	case BTF_KIND_INT:

		fprintf(out, " size=%u bits_offset=%u nr_bits=%u encoding=%s",

			t->size, btf_int_offset(t), btf_int_bits(t),

			btf_int_enc_str(btf_int_encoding(t)));

		break;

	case BTF_KIND_PTR:

	case BTF_KIND_CONST:

	case BTF_KIND_VOLATILE:

	case BTF_KIND_RESTRICT:

	case BTF_KIND_TYPEDEF:

		fprintf(out, " type_id=%u", t->type);

		break;

	case BTF_KIND_ARRAY: {

		const struct btf_array *arr = btf_array(t);



		fprintf(out, " type_id=%u index_type_id=%u nr_elems=%u",

			arr->type, arr->index_type, arr->nelems);

		break;

	}

	case BTF_KIND_STRUCT:

	case BTF_KIND_UNION: {

		const struct btf_member *m = btf_members(t);



		fprintf(out, " size=%u vlen=%u", t->size, vlen);

		for (i = 0; i < vlen; i++, m++) {

			__u32 bit_off, bit_sz;



			bit_off = btf_member_bit_offset(t, i);

			bit_sz = btf_member_bitfield_size(t, i);

			fprintf(out, "\n\t'%s' type_id=%u bits_offset=%u",

				btf_str(btf, m->name_off), m->type, bit_off);

			if (bit_sz)

				fprintf(out, " bitfield_size=%u", bit_sz);

		}

		break;

	}

	case BTF_KIND_ENUM: {

		const struct btf_enum *v = btf_enum(t);



		fprintf(out, " size=%u vlen=%u", t->size, vlen);

		for (i = 0; i < vlen; i++, v++) {

			fprintf(out, "\n\t'%s' val=%u",

				btf_str(btf, v->name_off), v->val);

		}

		break;

	}

	case BTF_KIND_FWD:

		fprintf(out, " fwd_kind=%s", btf_kflag(t) ? "union" : "struct");

		break;

	case BTF_KIND_FUNC:

		fprintf(out, " type_id=%u linkage=%s", t->type, btf_func_linkage_str(t));

		break;

	case BTF_KIND_FUNC_PROTO: {

		const struct btf_param *p = btf_params(t);



		fprintf(out, " ret_type_id=%u vlen=%u", t->type, vlen);

		for (i = 0; i < vlen; i++, p++) {

			fprintf(out, "\n\t'%s' type_id=%u",

				btf_str(btf, p->name_off), p->type);

		}

		break;

	}

	case BTF_KIND_VAR:

		fprintf(out, " type_id=%u, linkage=%s",

			t->type, btf_var_linkage_str(btf_var(t)->linkage));

		break;

	case BTF_KIND_DATASEC: {

		const struct btf_var_secinfo *v = btf_var_secinfos(t);



		fprintf(out, " size=%u vlen=%u", t->size, vlen);

		for (i = 0; i < vlen; i++, v++) {

			fprintf(out, "\n\ttype_id=%u offset=%u size=%u",

				v->type, v->offset, v->size);

		}

		break;

	}

	default:

		break;

	}



	return 0;

}



/* Print raw BTF type dump into a local buffer and return string pointer back.

 * Buffer *will* be overwritten by subsequent btf_type_raw_dump() calls

 */

const char *btf_type_raw_dump(const struct btf *btf, int type_id)

{

	static char buf[16 * 1024];

	FILE *buf_file;



	buf_file = fmemopen(buf, sizeof(buf) - 1, "w");

	if (!buf_file) {

		fprintf(stderr, "Failed to open memstream: %d\n", errno);

		return NULL;

	}



	fprintf_btf_type_raw(buf_file, btf, type_id);

	fflush(buf_file);

	fclose(buf_file);



	return buf;

}

tools/testing/selftests/bpf/btf_helpers.h

0 → 100644
+12 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

/* Copyright (c) 2020 Facebook */

#ifndef __BTF_HELPERS_H

#define __BTF_HELPERS_H



#include <stdio.h>

#include <bpf/btf.h>



int fprintf_btf_type_raw(FILE *out, const struct btf *btf, __u32 id);

const char *btf_type_raw_dump(const struct btf *btf, int type_id);



#endif

tools/testing/selftests/bpf/prog_tests/btf_write.c

+43 −0
Original line number Diff line number Diff line
@@ -2,6 +2,7 @@ 
/* Copyright (c) 2020 Facebook */

#include <test_progs.h>

#include <bpf/btf.h>

#include "btf_helpers.h"



static int duration = 0;
@@ -39,6 +40,8 @@ void test_btf_write() { 
	ASSERT_EQ(t->size, 4, "int_sz");

	ASSERT_EQ(btf_int_encoding(t), BTF_INT_SIGNED, "int_enc");

	ASSERT_EQ(btf_int_bits(t), 32, "int_bits");

	ASSERT_STREQ(btf_type_raw_dump(btf, 1),

		     "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", "raw_dump");



	/* invalid int size */

	id = btf__add_int(btf, "bad sz int", 7, 0);
@@ -59,24 +62,32 @@ void test_btf_write() { 
	t = btf__type_by_id(btf, 2);

	ASSERT_EQ(btf_kind(t), BTF_KIND_PTR, "ptr_kind");

	ASSERT_EQ(t->type, 1, "ptr_type");

	ASSERT_STREQ(btf_type_raw_dump(btf, 2),

		     "[2] PTR '(anon)' type_id=1", "raw_dump");



	id = btf__add_const(btf, 5); /* points forward to restrict */

	ASSERT_EQ(id, 3, "const_id");

	t = btf__type_by_id(btf, 3);

	ASSERT_EQ(btf_kind(t), BTF_KIND_CONST, "const_kind");

	ASSERT_EQ(t->type, 5, "const_type");

	ASSERT_STREQ(btf_type_raw_dump(btf, 3),

		     "[3] CONST '(anon)' type_id=5", "raw_dump");



	id = btf__add_volatile(btf, 3);

	ASSERT_EQ(id, 4, "volatile_id");

	t = btf__type_by_id(btf, 4);

	ASSERT_EQ(btf_kind(t), BTF_KIND_VOLATILE, "volatile_kind");

	ASSERT_EQ(t->type, 3, "volatile_type");

	ASSERT_STREQ(btf_type_raw_dump(btf, 4),

		     "[4] VOLATILE '(anon)' type_id=3", "raw_dump");



	id = btf__add_restrict(btf, 4);

	ASSERT_EQ(id, 5, "restrict_id");

	t = btf__type_by_id(btf, 5);

	ASSERT_EQ(btf_kind(t), BTF_KIND_RESTRICT, "restrict_kind");

	ASSERT_EQ(t->type, 4, "restrict_type");

	ASSERT_STREQ(btf_type_raw_dump(btf, 5),

		     "[5] RESTRICT '(anon)' type_id=4", "raw_dump");



	/* ARRAY */

	id = btf__add_array(btf, 1, 2, 10); /* int *[10] */
@@ -86,6 +97,8 @@ void test_btf_write() { 
	ASSERT_EQ(btf_array(t)->index_type, 1, "array_index_type");

	ASSERT_EQ(btf_array(t)->type, 2, "array_elem_type");

	ASSERT_EQ(btf_array(t)->nelems, 10, "array_nelems");

	ASSERT_STREQ(btf_type_raw_dump(btf, 6),

		     "[6] ARRAY '(anon)' type_id=2 index_type_id=1 nr_elems=10", "raw_dump");



	/* STRUCT */

	err = btf__add_field(btf, "field", 1, 0, 0);
@@ -113,6 +126,10 @@ void test_btf_write() { 
	ASSERT_EQ(m->type, 1, "f2_type");

	ASSERT_EQ(btf_member_bit_offset(t, 1), 32, "f2_bit_off");

	ASSERT_EQ(btf_member_bitfield_size(t, 1), 16, "f2_bit_sz");

	ASSERT_STREQ(btf_type_raw_dump(btf, 7),

		     "[7] STRUCT 's1' size=8 vlen=2\n"

		     "\t'f1' type_id=1 bits_offset=0\n"

		     "\t'f2' type_id=1 bits_offset=32 bitfield_size=16", "raw_dump");



	/* UNION */

	id = btf__add_union(btf, "u1", 8);
@@ -136,6 +153,9 @@ void test_btf_write() { 
	ASSERT_EQ(m->type, 1, "f1_type");

	ASSERT_EQ(btf_member_bit_offset(t, 0), 0, "f1_bit_off");

	ASSERT_EQ(btf_member_bitfield_size(t, 0), 16, "f1_bit_sz");

	ASSERT_STREQ(btf_type_raw_dump(btf, 8),

		     "[8] UNION 'u1' size=8 vlen=1\n"

		     "\t'f1' type_id=1 bits_offset=0 bitfield_size=16", "raw_dump");



	/* ENUM */

	id = btf__add_enum(btf, "e1", 4);
@@ -156,6 +176,10 @@ void test_btf_write() { 
	v = btf_enum(t) + 1;

	ASSERT_STREQ(btf__str_by_offset(btf, v->name_off), "v2", "v2_name");

	ASSERT_EQ(v->val, 2, "v2_val");

	ASSERT_STREQ(btf_type_raw_dump(btf, 9),

		     "[9] ENUM 'e1' size=4 vlen=2\n"

		     "\t'v1' val=1\n"

		     "\t'v2' val=2", "raw_dump");



	/* FWDs */

	id = btf__add_fwd(btf, "struct_fwd", BTF_FWD_STRUCT);
@@ -164,6 +188,8 @@ void test_btf_write() { 
	ASSERT_STREQ(btf__str_by_offset(btf, t->name_off), "struct_fwd", "fwd_name");

	ASSERT_EQ(btf_kind(t), BTF_KIND_FWD, "fwd_kind");

	ASSERT_EQ(btf_kflag(t), 0, "fwd_kflag");

	ASSERT_STREQ(btf_type_raw_dump(btf, 10),

		     "[10] FWD 'struct_fwd' fwd_kind=struct", "raw_dump");



	id = btf__add_fwd(btf, "union_fwd", BTF_FWD_UNION);

	ASSERT_EQ(id, 11, "union_fwd_id");
@@ -171,6 +197,8 @@ void test_btf_write() { 
	ASSERT_STREQ(btf__str_by_offset(btf, t->name_off), "union_fwd", "fwd_name");

	ASSERT_EQ(btf_kind(t), BTF_KIND_FWD, "fwd_kind");

	ASSERT_EQ(btf_kflag(t), 1, "fwd_kflag");

	ASSERT_STREQ(btf_type_raw_dump(btf, 11),

		     "[11] FWD 'union_fwd' fwd_kind=union", "raw_dump");



	id = btf__add_fwd(btf, "enum_fwd", BTF_FWD_ENUM);

	ASSERT_EQ(id, 12, "enum_fwd_id");
@@ -179,6 +207,8 @@ void test_btf_write() { 
	ASSERT_EQ(btf_kind(t), BTF_KIND_ENUM, "enum_fwd_kind");

	ASSERT_EQ(btf_vlen(t), 0, "enum_fwd_kind");

	ASSERT_EQ(t->size, 4, "enum_fwd_sz");

	ASSERT_STREQ(btf_type_raw_dump(btf, 12),

		     "[12] ENUM 'enum_fwd' size=4 vlen=0", "raw_dump");



	/* TYPEDEF */

	id = btf__add_typedef(btf, "typedef1", 1);
@@ -187,6 +217,8 @@ void test_btf_write() { 
	ASSERT_STREQ(btf__str_by_offset(btf, t->name_off), "typedef1", "typedef_name");

	ASSERT_EQ(btf_kind(t), BTF_KIND_TYPEDEF, "typedef_kind");

	ASSERT_EQ(t->type, 1, "typedef_type");

	ASSERT_STREQ(btf_type_raw_dump(btf, 13),

		     "[13] TYPEDEF 'typedef1' type_id=1", "raw_dump");



	/* FUNC & FUNC_PROTO */

	id = btf__add_func(btf, "func1", BTF_FUNC_GLOBAL, 15);
@@ -196,6 +228,8 @@ void test_btf_write() { 
	ASSERT_EQ(t->type, 15, "func_type");

	ASSERT_EQ(btf_kind(t), BTF_KIND_FUNC, "func_kind");

	ASSERT_EQ(btf_vlen(t), BTF_FUNC_GLOBAL, "func_vlen");

	ASSERT_STREQ(btf_type_raw_dump(btf, 14),

		     "[14] FUNC 'func1' type_id=15 linkage=global", "raw_dump");



	id = btf__add_func_proto(btf, 1);

	ASSERT_EQ(id, 15, "func_proto_id");
@@ -214,6 +248,10 @@ void test_btf_write() { 
	p = btf_params(t) + 1;

	ASSERT_STREQ(btf__str_by_offset(btf, p->name_off), "p2", "p2_name");

	ASSERT_EQ(p->type, 2, "p2_type");

	ASSERT_STREQ(btf_type_raw_dump(btf, 15),

		     "[15] FUNC_PROTO '(anon)' ret_type_id=1 vlen=2\n"

		     "\t'p1' type_id=1\n"

		     "\t'p2' type_id=2", "raw_dump");



	/* VAR */

	id = btf__add_var(btf, "var1", BTF_VAR_GLOBAL_ALLOCATED, 1);
@@ -223,6 +261,8 @@ void test_btf_write() { 
	ASSERT_EQ(btf_kind(t), BTF_KIND_VAR, "var_kind");

	ASSERT_EQ(t->type, 1, "var_type");

	ASSERT_EQ(btf_var(t)->linkage, BTF_VAR_GLOBAL_ALLOCATED, "var_type");

	ASSERT_STREQ(btf_type_raw_dump(btf, 16),

		     "[16] VAR 'var1' type_id=1, linkage=global-alloc", "raw_dump");



	/* DATASECT */

	id = btf__add_datasec(btf, "datasec1", 12);
@@ -239,6 +279,9 @@ void test_btf_write() { 
	ASSERT_EQ(vi->type, 1, "v1_type");

	ASSERT_EQ(vi->offset, 4, "v1_off");

	ASSERT_EQ(vi->size, 8, "v1_sz");

	ASSERT_STREQ(btf_type_raw_dump(btf, 17),

		     "[17] DATASEC 'datasec1' size=12 vlen=1\n"

		     "\ttype_id=1 offset=4 size=8", "raw_dump");



	btf__free(btf);

}