Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753966AbbKXNhE (ORCPT ); Tue, 24 Nov 2015 08:37:04 -0500 Received: from szxga01-in.huawei.com ([58.251.152.64]:19401 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752603AbbKXNg7 (ORCPT ); Tue, 24 Nov 2015 08:36:59 -0500 From: Wang Nan To: , , CC: , , , Wang Nan , He Kuang , "Arnaldo Carvalho de Melo" , Namhyung Kim Subject: [PATCH 05/16] bpf tools: Extract and collect map names from BPF object file Date: Tue, 24 Nov 2015 13:36:10 +0000 Message-ID: <1448372181-151723-6-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1448372181-151723-1-git-send-email-wangnan0@huawei.com> References: <1448372181-151723-1-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=0001.0A020203.565467F0.018C,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: fdea7bf64dc238a3508167103dd2b842 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5060 Lines: 168 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: 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 61c9f40..79b1dc2 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); + 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)) { @@ -581,10 +616,11 @@ 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); - else if (sh.sh_type == SHT_SYMTAB) { + maps_shndx = idx; + } else if (sh.sh_type == SHT_SYMTAB) { if (obj->efile.symbols) { pr_warning("bpf: multiple SYMTAB in %s\n", obj->path); @@ -625,6 +661,9 @@ 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; } @@ -1086,6 +1125,7 @@ void bpf_object__close(struct bpf_object *obj) bpf_object__unload(obj); for (i = 0; i < obj->nr_maps; i++) { + zfree(&obj->maps[i].name); if (obj->maps[i].clear_priv) obj->maps[i].clear_priv(&obj->maps[i], obj->maps[i].priv); @@ -1266,6 +1306,13 @@ 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) { @@ -1317,3 +1364,15 @@ 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 709d2fa..9bc0a56 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -170,6 +170,8 @@ 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); @@ -180,6 +182,7 @@ 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 -- 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/