Commit 29603665 authored by Wang Nan's avatar Wang Nan Committed by Arnaldo Carvalho de Melo
Browse files

bpf tools: Iterate over ELF sections to collect information 



bpf_obj_elf_collect() is introduced to iterate over each elf sections to
collection information in eBPF object files. This function will futher
enhanced to collect license, kernel version, programs, configs and map
information.

Signed-off-by: default avatarWang Nan <wangnan0@huawei.com>
Acked-by: default avatarAlexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1435716878-189507-9-git-send-email-wangnan0@huawei.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent cc4228d5

tools/lib/bpf/libbpf.c

+53 −0
Original line number Diff line number Diff line
@@ -220,6 +220,57 @@ mismatch: 
	return -EINVAL;

}



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;



	/* Elf is corrupted/truncated, avoid calling elf_strptr. */

	if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {

		pr_warning("failed to get e_shstrndx from %s\n",

			   obj->path);

		return -EINVAL;

	}



	while ((scn = elf_nextscn(elf, scn)) != NULL) {

		char *name;

		GElf_Shdr sh;

		Elf_Data *data;



		idx++;

		if (gelf_getshdr(scn, &sh) != &sh) {

			pr_warning("failed to get section header from %s\n",

				   obj->path);

			err = -EINVAL;

			goto out;

		}



		name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);

		if (!name) {

			pr_warning("failed to get section name from %s\n",

				   obj->path);

			err = -EINVAL;

			goto out;

		}



		data = elf_getdata(scn, 0);

		if (!data) {

			pr_warning("failed to get section data from %s(%s)\n",

				   name, obj->path);

			err = -EINVAL;

			goto out;

		}

		pr_debug("section %s, size %ld, link %d, flags %lx, type=%d\n",

			 name, (unsigned long)data->d_size,

			 (int)sh.sh_link, (unsigned long)sh.sh_flags,

			 (int)sh.sh_type);

	}

out:

	return err;

}



static struct bpf_object *

__bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz)

{
@@ -238,6 +289,8 @@ __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz) 
		goto out;

	if (bpf_object__check_endianness(obj))

		goto out;

	if (bpf_object__elf_collect(obj))

		goto out;



	bpf_object__elf_finish(obj);

	return obj;

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