From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753765AbbGIMqw (ORCPT ); Thu, 9 Jul 2015 08:46:52 -0400 Received: from szxga01-in.huawei.com ([58.251.152.64]:33612 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754474AbbGIMqV (ORCPT ); Thu, 9 Jul 2015 08:46:21 -0400 From: Wang Nan To: , CC: , , , , Subject: [PATCH 02/39] bpf tools: Collect eBPF programs from their own sections Date: Thu, 9 Jul 2015 12:35:05 +0000 Message-ID: <1436445342-1402-3-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1436445342-1402-1-git-send-email-wangnan0@huawei.com> References: <1436445342-1402-1-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 all programs in an object file into an array of 'struct bpf_program' for further processing. That structure is for representing each eBPF program. 'bpf_prog' should be a better name, but it has been used by linux/filter.h. Although it is a kernel space name, I still prefer to call it 'bpf_program' to prevent possible confusion. bpf_program__new() creates a new 'struct bpf_program' object. It first init a variable in stack using __bpf_program__new(), then if success, enlarges obj->programs array and copy the new object in. Signed-off-by: Wang Nan Acked-by: 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/r/1435716878-189507-13-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/lib/bpf/libbpf.c | 117 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 117 insertions(+) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 9b016c0..3b717de 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -78,12 +78,27 @@ void libbpf_set_print(libbpf_print_fn_t warn, # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ #endif +/* + * bpf_prog should be a better name but it has been used in + * linux/filter.h. + */ +struct bpf_program { + /* Index in elf obj file, for relocation use. */ + int idx; + char *section_name; + struct bpf_insn *insns; + size_t insns_cnt; +}; + struct bpf_object { char license[64]; u32 kern_version; void *maps_buf; size_t maps_buf_sz; + struct bpf_program *programs; + size_t nr_programs; + /* * Information when doing elf related work. Only valid if fd * is valid. @@ -100,6 +115,84 @@ struct bpf_object { }; #define obj_elf_valid(o) ((o)->efile.elf) +static void bpf_program__clear(struct bpf_program *prog) +{ + if (!prog) + return; + + zfree(&prog->section_name); + zfree(&prog->insns); + prog->insns_cnt = 0; + prog->idx = -1; +} + +static int +__bpf_program__new(void *data, size_t size, char *name, int idx, + struct bpf_program *prog) +{ + if (size < sizeof(struct bpf_insn)) { + pr_warning("corrupted section '%s'\n", name); + return -EINVAL; + } + + bzero(prog, sizeof(*prog)); + + prog->section_name = strdup(name); + if (!prog->section_name) { + pr_warning("failed to alloc name for prog %s\n", + name); + goto errout; + } + + prog->insns = malloc(size); + if (!prog->insns) { + pr_warning("failed to alloc insns for %s\n", name); + goto errout; + } + prog->insns_cnt = size / sizeof(struct bpf_insn); + memcpy(prog->insns, data, + prog->insns_cnt * sizeof(struct bpf_insn)); + prog->idx = idx; + + return 0; +errout: + bpf_program__clear(prog); + return -ENOMEM; +} + +static struct bpf_program * +bpf_program__new(struct bpf_object *obj, void *data, size_t size, + char *name, int idx) +{ + struct bpf_program prog, *progs; + int nr_progs, err; + + err = __bpf_program__new(data, size, name, idx, &prog); + if (err) + return NULL; + + progs = obj->programs; + nr_progs = obj->nr_programs; + + progs = realloc(progs, sizeof(progs[0]) * (nr_progs + 1)); + if (!progs) { + /* + * In this case the original obj->programs + * is still valid, so don't need special treat for + * bpf_close_object(). + */ + pr_warning("failed to alloc a new program '%s'\n", + name); + bpf_program__clear(&prog); + return NULL; + } + + obj->programs = progs; + obj->nr_programs = nr_progs + 1; + progs[nr_progs] = prog; + return &progs[nr_progs]; +} + static struct bpf_object *bpf_object__new(const char *path, void *obj_buf, size_t obj_buf_sz) @@ -342,6 +435,21 @@ static int bpf_object__elf_collect(struct bpf_object *obj) err = -EEXIST; } else obj->efile.symbols = data; + } else if ((sh.sh_type == SHT_PROGBITS) && + (sh.sh_flags & SHF_EXECINSTR) && + (data->d_size > 0)) { + struct bpf_program *prog; + + prog = bpf_program__new(obj, data->d_buf, + data->d_size, name, + idx); + if (!prog) { + pr_warning("failed to alloc program %s (%s)", + name, obj->path); + err = -ENOMEM; + } else + pr_debug("found program %s\n", + prog->section_name); } if (err) goto out; @@ -415,11 +523,20 @@ struct bpf_object *bpf_object__open_buffer(void *obj_buf, void bpf_object__close(struct bpf_object *obj) { + size_t i; + if (!obj) return; bpf_object__elf_finish(obj); zfree(&obj->maps_buf); + + if (obj->programs && obj->nr_programs) { + for (i = 0; i < obj->nr_programs; i++) + bpf_program__clear(&obj->programs[i]); + } + zfree(&obj->programs); + free(obj); } -- 1.8.3.4