From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 87240C76196 for ; Fri, 31 Mar 2023 09:33:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231718AbjCaJdH (ORCPT ); Fri, 31 Mar 2023 05:33:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232183AbjCaJcs (ORCPT ); Fri, 31 Mar 2023 05:32:48 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CD27B1EFD1 for ; Fri, 31 Mar 2023 02:32:25 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 385C6B82DC9 for ; Fri, 31 Mar 2023 09:32:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5790DC433EF; Fri, 31 Mar 2023 09:32:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1680255142; bh=pyNWgB+BYt6NpQv+YewnAK13rBDkOHmrmZ5nKooSB6o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eTA7RbfBKuibiGWD3ePU1wyxxanJKjdQzUrKHb+bcduXPLLWqcthSwlGwTdPI38UG SkbrhS9kc5o/mtnQUXYI+HGatGLXWAdzs2hviwgXyoAYvPwl29Q47+eOvXW/gEKqW+ A4ztvnJZ28U5jQM4P32cKit7mKN4P7pdSZPJ1Hspv/WyAMHVyn91LqSaz+CGZyPkGn nplyy/aWgrY8GXKhc2yhHiq62sJXFh1TyTgi+e8TD3DZQyPQODQ+cWD2duD+0MrM1c nfM5FL4rcpuUpgCY0DccycSnyvjCFSkHV0Ka4WLHUmDJmMjo1zNL0MO6ny6uqV3poa TaMd6yOE4xp0Q== From: Jiri Olsa To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: bpf@vger.kernel.org, Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo Subject: [PATCHv4 bpf-next 2/3] selftests/bpf: Add read_build_id function Date: Fri, 31 Mar 2023 11:31:56 +0200 Message-Id: <20230331093157.1749137-3-jolsa@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230331093157.1749137-1-jolsa@kernel.org> References: <20230331093157.1749137-1-jolsa@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Adding read_build_id function that parses out build id from specified binary. It will replace extract_build_id and also be used in following changes. Signed-off-by: Jiri Olsa --- tools/testing/selftests/bpf/trace_helpers.c | 82 +++++++++++++++++++++ tools/testing/selftests/bpf/trace_helpers.h | 5 ++ 2 files changed, 87 insertions(+) diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c index 934bf28fc888..9b070cdf44ac 100644 --- a/tools/testing/selftests/bpf/trace_helpers.c +++ b/tools/testing/selftests/bpf/trace_helpers.c @@ -11,6 +11,9 @@ #include #include #include "trace_helpers.h" +#include +#include +#include #define TRACEFS_PIPE "/sys/kernel/tracing/trace_pipe" #define DEBUGFS_PIPE "/sys/kernel/debug/tracing/trace_pipe" @@ -234,3 +237,82 @@ ssize_t get_rel_offset(uintptr_t addr) fclose(f); return -EINVAL; } + +static int +parse_build_id_buf(const void *note_start, Elf32_Word note_size, char *build_id) +{ + Elf32_Word note_offs = 0; + + while (note_offs + sizeof(Elf32_Nhdr) < note_size) { + Elf32_Nhdr *nhdr = (Elf32_Nhdr *)(note_start + note_offs); + + if (nhdr->n_type == 3 && nhdr->n_namesz == sizeof("GNU") && + !strcmp((char *)(nhdr + 1), "GNU") && nhdr->n_descsz > 0 && + nhdr->n_descsz <= BPF_BUILD_ID_SIZE) { + memcpy(build_id, note_start + note_offs + + ALIGN(sizeof("GNU"), 4) + sizeof(Elf32_Nhdr), nhdr->n_descsz); + memset(build_id + nhdr->n_descsz, 0, BPF_BUILD_ID_SIZE - nhdr->n_descsz); + return (int) nhdr->n_descsz; + } + + note_offs = note_offs + sizeof(Elf32_Nhdr) + + ALIGN(nhdr->n_namesz, 4) + ALIGN(nhdr->n_descsz, 4); + } + + return -ENOENT; +} + +/* Reads binary from *path* file and returns it in the *build_id* buffer + * with *size* which is expected to be at least BPF_BUILD_ID_SIZE bytes. + * Returns size of build id on success. On error the error value is + * returned. + */ +int read_build_id(const char *path, char *build_id, size_t size) +{ + int fd, err = -EINVAL; + Elf *elf = NULL; + GElf_Ehdr ehdr; + size_t max, i; + + if (size < BPF_BUILD_ID_SIZE) + return -EINVAL; + + fd = open(path, O_RDONLY | O_CLOEXEC); + if (fd < 0) + return -errno; + + (void)elf_version(EV_CURRENT); + + elf = elf_begin(fd, ELF_C_READ_MMAP, NULL); + if (!elf) + goto out; + if (elf_kind(elf) != ELF_K_ELF) + goto out; + if (!gelf_getehdr(elf, &ehdr)) + goto out; + + for (i = 0; i < ehdr.e_phnum; i++) { + GElf_Phdr mem, *phdr; + char *data; + + phdr = gelf_getphdr(elf, i, &mem); + if (!phdr) + goto out; + if (phdr->p_type != PT_NOTE) + continue; + data = elf_rawfile(elf, &max); + if (!data) + goto out; + if (phdr->p_offset + phdr->p_memsz > max) + goto out; + err = parse_build_id_buf(data + phdr->p_offset, phdr->p_memsz, build_id); + if (err > 0) + break; + } + +out: + if (elf) + elf_end(elf); + close(fd); + return err; +} diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/selftests/bpf/trace_helpers.h index 53efde0e2998..876f3e711df6 100644 --- a/tools/testing/selftests/bpf/trace_helpers.h +++ b/tools/testing/selftests/bpf/trace_helpers.h @@ -4,6 +4,9 @@ #include +#define __ALIGN_MASK(x, mask) (((x)+(mask))&~(mask)) +#define ALIGN(x, a) __ALIGN_MASK(x, (typeof(x))(a)-1) + struct ksym { long addr; char *name; @@ -23,4 +26,6 @@ void read_trace_pipe(void); ssize_t get_uprobe_offset(const void *addr); ssize_t get_rel_offset(uintptr_t addr); +int read_build_id(const char *path, char *build_id, size_t size); + #endif -- 2.39.2