From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933123AbbFIF6Q (ORCPT ); Tue, 9 Jun 2015 01:58:16 -0400 Received: from szxga01-in.huawei.com ([58.251.152.64]:63205 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753658AbbFIFvS (ORCPT ); Tue, 9 Jun 2015 01:51:18 -0400 From: Wang Nan To: , , , , , , , , , , CC: , , , , Subject: [RFC PATCH v6 12/32] bpf tools: Collect relocation sections from SHT_REL sections Date: Tue, 9 Jun 2015 05:50:16 +0000 Message-ID: <1433829036-23687-13-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1433829036-23687-1-git-send-email-wangnan0@huawei.com> References: <1433829036-23687-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.107.197.200] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch collects relocation sections into 'struct object'. Such sections are used for connecting maps to bpf programs. 'reloc' field in 'struct bpf_object' is introduced for storing such informations. This patch simply store the data into 'reloc' field. Following patch will parse them to know the exact instructions which are needed to be relocated. Note that the collected data will be invalid after ELF object file is closed. Signed-off-by: Wang Nan Acked-by: Alexei Starovoitov --- tools/lib/bpf/libbpf.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 91b2490..2b7f0f4 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -110,6 +110,11 @@ struct bpf_object { Elf *elf; GElf_Ehdr ehdr; Elf_Data *symbols; + struct { + GElf_Shdr shdr; + Elf_Data *data; + } *reloc; + int nr_reloc; } efile; char path[]; }; @@ -220,6 +225,9 @@ static void bpf_object__elf_finish(struct bpf_object *obj) obj->efile.elf = NULL; } obj->efile.symbols = NULL; + + zfree(&obj->efile.reloc); + obj->efile.nr_reloc = 0; zclose(obj->efile.fd); obj->efile.obj_buf = NULL; obj->efile.obj_buf_sz = 0; @@ -439,6 +447,24 @@ static int bpf_object__elf_collect(struct bpf_object *obj) } else pr_debug("found program %s\n", prog->section_name); + } else if (sh.sh_type == SHT_REL) { + void *reloc = obj->efile.reloc; + int nr_reloc = obj->efile.nr_reloc; + + reloc = realloc(reloc, + sizeof(*obj->efile.reloc) * (++nr_reloc)); + if (!reloc) { + pr_warning("realloc failed\n"); + err = -ENOMEM; + } else { + int n = nr_reloc - 1; + + obj->efile.reloc = reloc; + obj->efile.nr_reloc = nr_reloc; + + obj->efile.reloc[n].shdr = sh; + obj->efile.reloc[n].data = data; + } } if (err) goto out; -- 1.8.3.4