Commit cb1e5e96 authored by Wang Nan's avatar Wang Nan Committed by Arnaldo Carvalho de Melo
Browse files

bpf tools: Collect version and license from ELF sections 



Expand bpf_obj_elf_collect() to collect license and kernel version
information in eBPF object file. eBPF object file should have a section
named 'license', which contains a string. It should also have a section
named 'version', contains a u32 LINUX_VERSION_CODE.

bpf_obj_validate() is introduced to validate object file after loaded.
Currently it only check existence of 'version' section.

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/1435716878-189507-10-git-send-email-wangnan0@huawei.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 29603665

tools/lib/bpf/libbpf.c

+53 −0
Original line number Original line Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <fcntl.h>

#include <fcntl.h>

#include <errno.h>

#include <errno.h>

#include <asm/unistd.h>

#include <asm/unistd.h>

#include <linux/kernel.h>

#include <linux/bpf.h>

#include <linux/bpf.h>

#include <libelf.h>

#include <libelf.h>

#include <gelf.h>

#include <gelf.h>
@@ -78,6 +79,8 @@ void libbpf_set_print(libbpf_print_fn_t warn, 
#endif

#endif





struct bpf_object {

struct bpf_object {

	char license[64];

	u32 kern_version;

	/*

	/*

	 * Information when doing elf related work. Only valid if fd

	 * Information when doing elf related work. Only valid if fd

	 * is valid.

	 * is valid.
@@ -220,6 +223,33 @@ mismatch: 
	return -EINVAL;

	return -EINVAL;

}

}





static int

bpf_object__init_license(struct bpf_object *obj,

			 void *data, size_t size)

{

	memcpy(obj->license, data,

	       min(size, sizeof(obj->license) - 1));

	pr_debug("license of %s is %s\n", obj->path, obj->license);

	return 0;

}



static int

bpf_object__init_kversion(struct bpf_object *obj,

			  void *data, size_t size)

{

	u32 kver;



	if (size != sizeof(kver)) {

		pr_warning("invalid kver section in %s\n", obj->path);

		return -EINVAL;

	}

	memcpy(&kver, data, sizeof(kver));

	obj->kern_version = kver;

	pr_debug("kernel version of %s is %x\n", obj->path,

		 obj->kern_version);

	return 0;

}



static int bpf_object__elf_collect(struct bpf_object *obj)

static int bpf_object__elf_collect(struct bpf_object *obj)

{

{

	Elf *elf = obj->efile.elf;

	Elf *elf = obj->efile.elf;
@@ -266,11 +296,32 @@ static int bpf_object__elf_collect(struct bpf_object *obj) 
			 name, (unsigned long)data->d_size,

			 name, (unsigned long)data->d_size,

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

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

			 (int)sh.sh_type);

			 (int)sh.sh_type);



		if (strcmp(name, "license") == 0)

			err = bpf_object__init_license(obj,

						       data->d_buf,

						       data->d_size);

		else if (strcmp(name, "version") == 0)

			err = bpf_object__init_kversion(obj,

							data->d_buf,

							data->d_size);

		if (err)

			goto out;

	}

	}

out:

out:

	return err;

	return err;

}

}





static int bpf_object__validate(struct bpf_object *obj)

{

	if (obj->kern_version == 0) {

		pr_warning("%s doesn't provide kernel version\n",

			   obj->path);

		return -EINVAL;

	}

	return 0;

}



static struct bpf_object *

static struct bpf_object *

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

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

{

{
@@ -291,6 +342,8 @@ __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz) 
		goto out;

		goto out;

	if (bpf_object__elf_collect(obj))

	if (bpf_object__elf_collect(obj))

		goto out;

		goto out;

	if (bpf_object__validate(obj))

		goto out;





	bpf_object__elf_finish(obj);

	bpf_object__elf_finish(obj);

	return obj;

	return obj;

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