Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752022AbbK2QPJ (ORCPT ); Sun, 29 Nov 2015 11:15:09 -0500 Received: from mail-pa0-f47.google.com ([209.85.220.47]:34855 "EHLO mail-pa0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751501AbbK2QPG (ORCPT ); Sun, 29 Nov 2015 11:15:06 -0500 Date: Mon, 30 Nov 2015 01:14:34 +0900 From: Namhyung Kim To: Wang Nan Cc: acme@kernel.org, ast@kernel.org, linux-kernel@vger.kernel.org, masami.hiramatsu.pt@hitachi.com, lizefan@huawei.com, pi3orama@163.com, He Kuang , Arnaldo Carvalho de Melo Subject: Re: [PATCH v2 02/13] bpf tools: Extract and collect map names from BPF object file Message-ID: <20151129161434.GE16382@danjae.kornet> References: <1448614067-197576-1-git-send-email-wangnan0@huawei.com> <1448614067-197576-3-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1448614067-197576-3-git-send-email-wangnan0@huawei.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2549 Lines: 86 Hi Wang, On Fri, Nov 27, 2015 at 08:47:36AM +0000, Wang Nan wrote: > This patch collects name of maps in BPF object files and saves them into > 'maps' field in 'struct bpf_object'. 'bpf_object__get_map_by_name' is > introduced to retrive fd and definitions of a map through its name. > > Signed-off-by: Wang Nan > Signed-off-by: He Kuang > Cc: Alexei Starovoitov > Cc: Arnaldo Carvalho de Melo > Cc: Masami Hiramatsu > Cc: Namhyung Kim > Cc: Zefan Li > Cc: pi3orama@163.com > --- > tools/lib/bpf/libbpf.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++--- > tools/lib/bpf/libbpf.h | 3 +++ > 2 files changed, 65 insertions(+), 3 deletions(-) > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > index f509825..a298614 100644 > --- a/tools/lib/bpf/libbpf.c > +++ b/tools/lib/bpf/libbpf.c > @@ -165,6 +165,7 @@ struct bpf_program { > > struct bpf_map { > int fd; > + char *name; > struct bpf_map_def def; > void *priv; > bpf_map_clear_priv_t clear_priv; > @@ -526,12 +527,46 @@ bpf_object__init_maps(struct bpf_object *obj, void *data, > return 0; > } > > +static void > +bpf_object__init_maps_name(struct bpf_object *obj, int maps_shndx) > +{ > + int i; > + Elf_Data *symbols = obj->efile.symbols; > + > + if (!symbols || maps_shndx < 0) > + return; > + > + for (i = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) { > + GElf_Sym sym; > + size_t map_idx; > + const char *map_name; > + > + if (!gelf_getsym(symbols, i, &sym)) > + continue; > + if (sym.st_shndx != maps_shndx) > + continue; > + > + map_name = elf_strptr(obj->efile.elf, > + obj->efile.ehdr.e_shstrndx, > + sym.st_name); It means that each map name is saved in section header string table? > + map_idx = sym.st_value / sizeof(struct bpf_map_def); > + if (map_idx >= obj->nr_maps) { > + pr_warning("index of map \"%s\" is buggy: %zu > %zu\n", > + map_name, map_idx, obj->nr_maps); > + continue; > + } > + obj->maps[map_idx].name = strdup(map_name); You need to check the return value. thanks, Namhyung > + pr_debug("map %zu is \"%s\"\n", map_idx, > + obj->maps[map_idx].name); > + } > +} > + -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/