From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932444AbbJNMvZ (ORCPT ); Wed, 14 Oct 2015 08:51:25 -0400 Received: from szxga03-in.huawei.com ([119.145.14.66]:27780 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753542AbbJNMmq (ORCPT ); Wed, 14 Oct 2015 08:42:46 -0400 From: Wang Nan To: , , CC: , , , , , , , , , , , , Wang Nan , Arnaldo Carvalho de Melo Subject: [PATCH 25/31] bpf tools: Extract and collect map names from BPF object file Date: Wed, 14 Oct 2015 12:41:36 +0000 Message-ID: <1444826502-49291-26-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1444826502-49291-1-git-send-email-wangnan0@huawei.com> References: <1444826502-49291-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.107.193.248] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020203.561E4DC3.0143,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 0949f9426c1c90483035c8d5c5c177d8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch collect name of map in BPF object files and saves them into 'maps' field in 'struct bpf_object'. 'bpf_object__get_map_by_name' is introduced to retrive map fd and definitions through its name. Signed-off-by: Wang Nan Signed-off-by: He Kuang Cc: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Brendan Gregg Cc: Daniel Borkmann Cc: David Ahern Cc: He Kuang Cc: Jiri Olsa Cc: Kaixu Xia Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/n/ebpf-ccbekxapr4xy91a3z57xctj0@git.kernel.org --- tools/lib/bpf/libbpf.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++-- tools/lib/bpf/libbpf.h | 3 +++ 2 files changed, 64 insertions(+), 2 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 8ae501b..c4283c7 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -111,6 +111,7 @@ struct bpf_program { struct bpf_map { int fd; + char *name; struct bpf_map_def def; void *priv; bpf_map_clear_priv_t clear_priv; @@ -471,12 +472,46 @@ 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); + 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); + pr_debug("map %zu is \"%s\"\n", map_idx, + obj->maps[map_idx].name); + } +} + static int bpf_object__elf_collect(struct bpf_object *obj) { Elf *elf = obj->efile.elf; GElf_Ehdr *ep = &obj->efile.ehdr; Elf_Scn *scn = NULL; - int idx = 0, err = 0; + int idx = 0, err = 0, maps_shndx = -1; /* Elf is corrupted/truncated, avoid calling elf_strptr. */ if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) { @@ -526,9 +561,11 @@ static int bpf_object__elf_collect(struct bpf_object *obj) err = bpf_object__init_kversion(obj, data->d_buf, data->d_size); - else if (strcmp(name, "maps") == 0) + else if (strcmp(name, "maps") == 0) { err = bpf_object__init_maps(obj, data->d_buf, data->d_size); + maps_shndx = idx; + } else if (sh.sh_type == SHT_SYMTAB) { if (obj->efile.symbols) { pr_warning("bpf: multiple SYMTAB in %s\n", @@ -569,6 +606,9 @@ static int bpf_object__elf_collect(struct bpf_object *obj) if (err) goto out; } + + if (maps_shndx >= 0) + bpf_object__init_maps_name(obj, maps_shndx); out: return err; } @@ -1194,6 +1234,13 @@ int bpf_map__get_def(struct bpf_map *map, struct bpf_map_def *pdef) return 0; } +const char *bpf_map__get_name(struct bpf_map *map) +{ + if (!map) + return NULL; + return map->name; +} + int bpf_map__set_private(struct bpf_map *map, void *priv, bpf_map_clear_priv_t clear_priv) { @@ -1245,3 +1292,15 @@ bpf_map__next(struct bpf_map *prev, struct bpf_object *obj) return NULL; return &obj->maps[idx]; } + +struct bpf_map * +bpf_object__get_map_by_name(struct bpf_object *obj, const char *name) +{ + struct bpf_map *pos; + + bpf_map__for_each(pos, obj) { + if (strcmp(pos->name, name) == 0) + return pos; + } + return NULL; +} diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index a3bf71e..37b8f27 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -107,6 +107,8 @@ struct bpf_map_def { * it is not a uapi header so no need to consider name confliction. */ struct bpf_map; +struct bpf_map * +bpf_object__get_map_by_name(struct bpf_object *obj, const char *name); struct bpf_map * bpf_map__next(struct bpf_map *map, struct bpf_object *obj); @@ -117,6 +119,7 @@ bpf_map__next(struct bpf_map *map, struct bpf_object *obj); int bpf_map__get_fd(struct bpf_map *map); int bpf_map__get_def(struct bpf_map *map, struct bpf_map_def *pdef); +const char *bpf_map__get_name(struct bpf_map *map); typedef void (*bpf_map_clear_priv_t)(struct bpf_map *, void *); int bpf_map__set_private(struct bpf_map *map, void *priv, -- 1.8.3.4