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Commit aa9b1ac3 authored by Wang Nan's avatar Wang Nan Committed by Arnaldo Carvalho de Melo
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bpf tools: Introduce accessors for struct bpf_program 



This patch introduces accessors for user of libbpf to retrieve section
name and fd of a opened/loaded eBPF program. 'struct bpf_prog_handler'
is used for that purpose. Accessors of programs section name and file
descriptor are provided. Set/get private data are also impelmented.

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>
Link: http://lkml.kernel.org/r/1435716878-189507-21-git-send-email-wangnan0@huawei.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 55cffde2

tools/lib/bpf/libbpf.c

+72 −0
Original line number Diff line number Diff line
@@ -98,6 +98,10 @@ struct bpf_program { 
	int nr_reloc;



	int fd;



	struct bpf_object *obj;

	void *priv;

	bpf_program_clear_priv_t clear_priv;

};



struct bpf_object {
@@ -150,6 +154,12 @@ static void bpf_program__exit(struct bpf_program *prog) 
	if (!prog)

		return;



	if (prog->clear_priv)

		prog->clear_priv(prog, prog->priv);



	prog->priv = NULL;

	prog->clear_priv = NULL;



	bpf_program__unload(prog);

	zfree(&prog->section_name);

	zfree(&prog->insns);
@@ -225,6 +235,7 @@ bpf_object__add_program(struct bpf_object *obj, void *data, size_t size, 
	pr_debug("found program %s\n", prog.section_name);

	obj->programs = progs;

	obj->nr_programs = nr_progs + 1;

	prog.obj = obj;

	progs[nr_progs] = prog;

	return 0;

}
@@ -931,3 +942,64 @@ void bpf_object__close(struct bpf_object *obj) 


	free(obj);

}



struct bpf_program *

bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)

{

	size_t idx;



	if (!obj->programs)

		return NULL;

	/* First handler */

	if (prev == NULL)

		return &obj->programs[0];



	if (prev->obj != obj) {

		pr_warning("error: program handler doesn't match object\n");

		return NULL;

	}



	idx = (prev - obj->programs) + 1;

	if (idx >= obj->nr_programs)

		return NULL;

	return &obj->programs[idx];

}



int bpf_program__set_private(struct bpf_program *prog,

			     void *priv,

			     bpf_program_clear_priv_t clear_priv)

{

	if (prog->priv && prog->clear_priv)

		prog->clear_priv(prog, prog->priv);



	prog->priv = priv;

	prog->clear_priv = clear_priv;

	return 0;

}



int bpf_program__get_private(struct bpf_program *prog, void **ppriv)

{

	*ppriv = prog->priv;

	return 0;

}



const char *bpf_program__title(struct bpf_program *prog, bool dup)

{

	const char *title;



	title = prog->section_name;

	if (dup) {

		title = strdup(title);

		if (!title) {

			pr_warning("failed to strdup program title\n");

			return NULL;

		}

	}



	return title;

}



int bpf_program__fd(struct bpf_program *prog)

{

	return prog->fd;

}

tools/lib/bpf/libbpf.h

+24 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#define __BPF_LIBBPF_H



#include <stdio.h>

#include <stdbool.h>



/*

 * In include/linux/compiler-gcc.h, __printf is defined. However
@@ -34,6 +35,29 @@ void bpf_object__close(struct bpf_object *object); 
int bpf_object__load(struct bpf_object *obj);

int bpf_object__unload(struct bpf_object *obj);



/* Accessors of bpf_program. */

struct bpf_program;

struct bpf_program *bpf_program__next(struct bpf_program *prog,

				      struct bpf_object *obj);



#define bpf_object__for_each_program(pos, obj)		\

	for ((pos) = bpf_program__next(NULL, (obj));	\

	     (pos) != NULL;				\

	     (pos) = bpf_program__next((pos), (obj)))



typedef void (*bpf_program_clear_priv_t)(struct bpf_program *,

					 void *);



int bpf_program__set_private(struct bpf_program *prog, void *priv,

			     bpf_program_clear_priv_t clear_priv);



int bpf_program__get_private(struct bpf_program *prog,

			     void **ppriv);



const char *bpf_program__title(struct bpf_program *prog, bool dup);



int bpf_program__fd(struct bpf_program *prog);



/*

 * We don't need __attribute__((packed)) now since it is

 * unnecessary for 'bpf_map_def' because they are all aligned.