From patchwork Tue Feb 28 09:32:02 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiri Olsa X-Patchwork-Id: 13154595 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 3A69FC7EE32 for ; Tue, 28 Feb 2023 09:33:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231354AbjB1Jdf (ORCPT ); Tue, 28 Feb 2023 04:33:35 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48232 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231370AbjB1Jd3 (ORCPT ); Tue, 28 Feb 2023 04:33:29 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9E39F1E28F; Tue, 28 Feb 2023 01:33:20 -0800 (PST) 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 31E3FB80D3A; Tue, 28 Feb 2023 09:33:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C43FEC433D2; Tue, 28 Feb 2023 09:33:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1677576797; bh=c9z68q+WdAEZYqVryh8zZBbeNYueFUIM9/Jpow2jaNA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ig3GSFl6mH1gtKMNYEwibcAW7JNIHR8jX9SMP4+o1z10djXhgAmdA70qQeTXISQwj 6kmZOFt/BRo35UGXyT0MyxaJM2gT20Dc/OAvY/sOrQLOkc1UPuDL+3nYvsJ5vey6SW 78yXIfTc8YS62UD+6vhwCq+Mdh1g8lCRcT44EX9+Sjbv8IAoiTAsjrvxw93aTKTX0i jTtDaeU5cvMgDE4B0W/LxBiMBgmc0rCvJv4xKYYwWK/rCxNSmZ6AIcQgPyhCDqQK7X GQVQJa8izimvaKUlWPYrb5rvrs0dQg1E9pF77uWyFo0d+kPaNk+ahJXpO+hArWBPYa Tvd2HkhnVTk4w== From: Jiri Olsa To: Alexei Starovoitov , Andrii Nakryiko , Hao Luo , Andrew Morton , Alexander Viro , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Matthew Wilcox Cc: bpf@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-perf-users@vger.kernel.org, Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Daniel Borkmann , Namhyung Kim Subject: [PATCH RFC v2 bpf-next 5/9] selftests/bpf: Add read_buildid function Date: Tue, 28 Feb 2023 10:32:02 +0100 Message-Id: <20230228093206.821563-6-jolsa@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230228093206.821563-1-jolsa@kernel.org> References: <20230228093206.821563-1-jolsa@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@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 | 98 +++++++++++++++++++++ tools/testing/selftests/bpf/trace_helpers.h | 5 ++ 2 files changed, 103 insertions(+) diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c index 09a16a77bae4..c10e16626cd3 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 DEBUGFS "/sys/kernel/debug/tracing/" @@ -230,3 +233,98 @@ 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, new_offs; + + 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; + } + + new_offs = note_offs + sizeof(Elf32_Nhdr) + + ALIGN(nhdr->n_namesz, 4) + ALIGN(nhdr->n_descsz, 4); + + if (new_offs >= note_size) + break; + note_offs = new_offs; + } + + return -EINVAL; +} + +/* Reads binary from *path* file and returns it in the *build_id* + * 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) +{ + int fd, err = -EINVAL; + Elf *elf = NULL; + GElf_Ehdr ehdr; + size_t max, i; + + fd = open(path, O_RDONLY | O_CLOEXEC); + if (fd < 0) + return -errno; + + (void)elf_version(EV_CURRENT); + + elf = elf_begin(fd, ELF_C_READ, NULL); + if (!elf) + goto out; + + if (elf_kind(elf) != ELF_K_ELF) + goto out; + + if (gelf_getehdr(elf, &ehdr) == NULL) + goto out; + + if (ehdr.e_ident[EI_CLASS] != ELFCLASS64) + 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 >= max || + (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) + goto out; + } + +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..50b2cc498ba7 100644 --- a/tools/testing/selftests/bpf/trace_helpers.h +++ b/tools/testing/selftests/bpf/trace_helpers.h @@ -4,6 +4,9 @@ #include +#define ALIGN(x, a) __ALIGN_MASK(x, (typeof(x))(a)-1) +#define __ALIGN_MASK(x, mask) (((x)+(mask))&~(mask)) + 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); + #endif