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Commit 55cffde2 authored by Wang Nan's avatar Wang Nan Committed by Arnaldo Carvalho de Melo
Browse files

bpf tools: Load eBPF programs in object files into kernel 



This patch utilizes previous introduced bpf_load_program to load
programs in the ELF file into kernel. Result is stored in 'fd' field in
'struct bpf_program'.

During loading, it allocs a log buffer and free it before return.  Note
that that buffer is not passed to bpf_load_program() if the first
loading try is successful. Doesn't use a statically allocated log buffer
to avoid potention multi-thread problem.

Instructions collected during opening is cleared after loading.

load_program() is created for loading a 'struct bpf_insn' array into
kernel, bpf_program__load() calls it. By this design we have a function
loads instructions into kernel. It will be used by further patches,
which creates different instances from a program and load them into
kernel.

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/1435716878-189507-20-git-send-email-wangnan0@huawei.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 7bf98369

tools/lib/bpf/libbpf.c

+90 −0
Original line number Diff line number Diff line
@@ -96,6 +96,8 @@ struct bpf_program { 
		int map_idx;

	} *reloc_desc;

	int nr_reloc;



	int fd;

};



struct bpf_object {
@@ -135,11 +137,20 @@ struct bpf_object { 
};

#define obj_elf_valid(o)	((o)->efile.elf)



static void bpf_program__unload(struct bpf_program *prog)

{

	if (!prog)

		return;



	zclose(prog->fd);

}



static void bpf_program__exit(struct bpf_program *prog)

{

	if (!prog)

		return;



	bpf_program__unload(prog);

	zfree(&prog->section_name);

	zfree(&prog->insns);

	zfree(&prog->reloc_desc);
@@ -176,6 +187,7 @@ bpf_program__init(void *data, size_t size, char *name, int idx, 
	memcpy(prog->insns, data,

	       prog->insns_cnt * sizeof(struct bpf_insn));

	prog->idx = idx;

	prog->fd = -1;



	return 0;

errout:
@@ -718,6 +730,79 @@ static int bpf_object__collect_reloc(struct bpf_object *obj) 
	return 0;

}



static int

load_program(struct bpf_insn *insns, int insns_cnt,

	     char *license, u32 kern_version, int *pfd)

{

	int ret;

	char *log_buf;



	if (!insns || !insns_cnt)

		return -EINVAL;



	log_buf = malloc(BPF_LOG_BUF_SIZE);

	if (!log_buf)

		pr_warning("Alloc log buffer for bpf loader error, continue without log\n");



	ret = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns,

			       insns_cnt, license, kern_version,

			       log_buf, BPF_LOG_BUF_SIZE);



	if (ret >= 0) {

		*pfd = ret;

		ret = 0;

		goto out;

	}



	ret = -EINVAL;

	pr_warning("load bpf program failed: %s\n", strerror(errno));



	if (log_buf) {

		pr_warning("-- BEGIN DUMP LOG ---\n");

		pr_warning("\n%s\n", log_buf);

		pr_warning("-- END LOG --\n");

	}



out:

	free(log_buf);

	return ret;

}



static int

bpf_program__load(struct bpf_program *prog,

		  char *license, u32 kern_version)

{

	int err, fd;



	err = load_program(prog->insns, prog->insns_cnt,

			   license, kern_version, &fd);

	if (!err)

		prog->fd = fd;



	if (err)

		pr_warning("failed to load program '%s'\n",

			   prog->section_name);

	zfree(&prog->insns);

	prog->insns_cnt = 0;

	return err;

}



static int

bpf_object__load_progs(struct bpf_object *obj)

{

	size_t i;

	int err;



	for (i = 0; i < obj->nr_programs; i++) {

		err = bpf_program__load(&obj->programs[i],

					obj->license,

					obj->kern_version);

		if (err)

			return err;

	}

	return 0;

}



static int bpf_object__validate(struct bpf_object *obj)

{

	if (obj->kern_version == 0) {
@@ -795,6 +880,9 @@ int bpf_object__unload(struct bpf_object *obj) 
	zfree(&obj->map_fds);

	obj->nr_map_fds = 0;



	for (i = 0; i < obj->nr_programs; i++)

		bpf_program__unload(&obj->programs[i]);



	return 0;

}
@@ -813,6 +901,8 @@ int bpf_object__load(struct bpf_object *obj) 
		goto out;

	if (bpf_object__relocate(obj))

		goto out;

	if (bpf_object__load_progs(obj))

		goto out;



	return 0;

out: