Re: [PATCH bpf-next 06/11] selftests/bpf: add checking of raw type dump in BTF writer APIs selftests
From: Song Liu <hidden>
Date: 2020-11-03 00:08:25
Also in:
bpf
On Oct 28, 2020, at 5:58 PM, Andrii Nakryiko [off-list ref] wrote:
From: Andrii Nakryiko <redacted>
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: Andrii Nakryiko <andrii@kernel.org>Acked-by: Song Liu <redacted> with a couple nits: [...]
quoted hunk ↗ jump to hunk
+ +/* 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; +}diff --git a/tools/testing/selftests/bpf/btf_helpers.h b/tools/testing/selftests/bpf/btf_helpers.h new file mode 100644 index 000000000000..2c9ce1b61dc9 --- /dev/null +++ b/tools/testing/selftests/bpf/btf_helpers.h@@ -0,0 +1,12 @@ +/* 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); + +#endifdiff --git a/tools/testing/selftests/bpf/prog_tests/btf_write.c b/tools/testing/selftests/bpf/prog_tests/btf_write.c index 314e1e7c36df..bc1412de1b3d 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf_write.c +++ b/tools/testing/selftests/bpf/prog_tests/btf_write.c@@ -2,6 +2,7 @@/* Copyright (c) 2020 Facebook */ #include <test_progs.h> #include <bpf/btf.h> +#include "btf_helpers.h" static int duration = 0;@@ -11,12 +12,12 @@ void test_btf_write() {const struct btf_member *m; const struct btf_enum *v; const struct btf_param *p; - struct btf *btf; + struct btf *btf = NULL;
No need to initialize btf.
int id, err, str_off; btf = btf__new_empty(); if (CHECK(IS_ERR(btf), "new_empty", "failed: %ld\n", PTR_ERR(btf))) - return; + goto err_out;
err_out is not needed either. [...]