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Commit 9d759a9b authored by Wang Nan's avatar Wang Nan Committed by Arnaldo Carvalho de Melo
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tools lib bpf: Collect map definition in bpf_object 



This patch collects more information from maps sections in BPF object
files into 'struct bpf_object', enables later patches access those
information (such as the type and size of the map).

In this patch, a new handler 'struct bpf_map' is extracted in parallel
with bpf_object and bpf_program. Its iterator and accessor is also
created.

Signed-off-by: default avatarWang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1448614067-197576-2-git-send-email-wangnan0@huawei.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 03905048

tools/lib/bpf/libbpf.c

+127 −60
Original line number Diff line number Diff line
@@ -163,22 +163,24 @@ struct bpf_program { 
	bpf_program_clear_priv_t clear_priv;

};



struct bpf_map {

	int fd;

	struct bpf_map_def def;

	void *priv;

	bpf_map_clear_priv_t clear_priv;

};



static LIST_HEAD(bpf_objects_list);



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;

	int *map_fds;

	/*

	 * This field is required because maps_buf will be freed and

	 * maps_buf_sz will be set to 0 after loaded.

	 */

	size_t nr_map_fds;

	struct bpf_map *maps;

	size_t nr_maps;



	bool loaded;



	/*
@@ -489,21 +491,38 @@ static int 
bpf_object__init_maps(struct bpf_object *obj, void *data,

		      size_t size)

{

	if (size == 0) {

	size_t nr_maps;

	int i;



	nr_maps = size / sizeof(struct bpf_map_def);

	if (!data || !nr_maps) {

		pr_debug("%s doesn't need map definition\n",

			 obj->path);

		return 0;

	}



	obj->maps_buf = malloc(size);

	if (!obj->maps_buf) {

		pr_warning("malloc maps failed: %s\n", obj->path);

	pr_debug("maps in %s: %zd bytes\n", obj->path, size);



	obj->maps = calloc(nr_maps, sizeof(obj->maps[0]));

	if (!obj->maps) {

		pr_warning("alloc maps for object failed\n");

		return -ENOMEM;

	}

	obj->nr_maps = nr_maps;



	for (i = 0; i < nr_maps; i++) {

		struct bpf_map_def *def = &obj->maps[i].def;



		/*

		 * fill all fd with -1 so won't close incorrect

		 * fd (fd=0 is stdin) when failure (zclose won't close

		 * negative fd)).

		 */

		obj->maps[i].fd = -1;



	obj->maps_buf_sz = size;

	memcpy(obj->maps_buf, data, size);

	pr_debug("maps in %s: %ld bytes\n", obj->path, (long)size);

		/* Save map definition into obj->maps */

		*def = ((struct bpf_map_def *)data)[i];

	}

	return 0;

}
@@ -688,37 +707,15 @@ static int 
bpf_object__create_maps(struct bpf_object *obj)

{

	unsigned int i;

	size_t nr_maps;

	int *pfd;



	nr_maps = obj->maps_buf_sz / sizeof(struct bpf_map_def);

	if (!obj->maps_buf || !nr_maps) {

		pr_debug("don't need create maps for %s\n",

			 obj->path);

		return 0;

	}



	obj->map_fds = malloc(sizeof(int) * nr_maps);

	if (!obj->map_fds) {

		pr_warning("realloc perf_bpf_map_fds failed\n");

		return -ENOMEM;

	}

	obj->nr_map_fds = nr_maps;



	/* fill all fd with -1 */

	memset(obj->map_fds, -1, sizeof(int) * nr_maps);



	pfd = obj->map_fds;

	for (i = 0; i < nr_maps; i++) {

		struct bpf_map_def def;



		def = *(struct bpf_map_def *)(obj->maps_buf +

				i * sizeof(struct bpf_map_def));

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

		struct bpf_map_def *def = &obj->maps[i].def;

		int *pfd = &obj->maps[i].fd;



		*pfd = bpf_create_map(def.type,

				      def.key_size,

				      def.value_size,

				      def.max_entries);

		*pfd = bpf_create_map(def->type,

				      def->key_size,

				      def->value_size,

				      def->max_entries);

		if (*pfd < 0) {

			size_t j;

			int err = *pfd;
@@ -726,22 +723,17 @@ bpf_object__create_maps(struct bpf_object *obj) 
			pr_warning("failed to create map: %s\n",

				   strerror(errno));

			for (j = 0; j < i; j++)

				zclose(obj->map_fds[j]);

			obj->nr_map_fds = 0;

			zfree(&obj->map_fds);

				zclose(obj->maps[j].fd);

			return err;

		}

		pr_debug("create map: fd=%d\n", *pfd);

		pfd++;

	}



	zfree(&obj->maps_buf);

	obj->maps_buf_sz = 0;

	return 0;

}



static int

bpf_program__relocate(struct bpf_program *prog, int *map_fds)

bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)

{

	int i;
@@ -761,7 +753,7 @@ bpf_program__relocate(struct bpf_program *prog, int *map_fds) 
			return -LIBBPF_ERRNO__RELOC;

		}

		insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;

		insns[insn_idx].imm = map_fds[map_idx];

		insns[insn_idx].imm = obj->maps[map_idx].fd;

	}



	zfree(&prog->reloc_desc);
@@ -780,7 +772,7 @@ bpf_object__relocate(struct bpf_object *obj) 
	for (i = 0; i < obj->nr_programs; i++) {

		prog = &obj->programs[i];



		err = bpf_program__relocate(prog, obj->map_fds);

		err = bpf_program__relocate(prog, obj);

		if (err) {

			pr_warning("failed to relocate '%s'\n",

				   prog->section_name);
@@ -804,8 +796,7 @@ static int bpf_object__collect_reloc(struct bpf_object *obj) 
		Elf_Data *data = obj->efile.reloc[i].data;

		int idx = shdr->sh_info;

		struct bpf_program *prog;

		size_t nr_maps = obj->maps_buf_sz /

				 sizeof(struct bpf_map_def);

		size_t nr_maps = obj->nr_maps;



		if (shdr->sh_type != SHT_REL) {

			pr_warning("internal error at %d\n", __LINE__);
@@ -1050,10 +1041,8 @@ int bpf_object__unload(struct bpf_object *obj) 
	if (!obj)

		return -EINVAL;



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

		zclose(obj->map_fds[i]);

	zfree(&obj->map_fds);

	obj->nr_map_fds = 0;

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

		zclose(obj->maps[i].fd);



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

		bpf_program__unload(&obj->programs[i]);
@@ -1096,7 +1085,15 @@ void bpf_object__close(struct bpf_object *obj) 
	bpf_object__elf_finish(obj);

	bpf_object__unload(obj);



	zfree(&obj->maps_buf);

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

		if (obj->maps[i].clear_priv)

			obj->maps[i].clear_priv(&obj->maps[i],

						obj->maps[i].priv);

		obj->maps[i].priv = NULL;

		obj->maps[i].clear_priv = NULL;

	}

	zfree(&obj->maps);

	obj->nr_maps = 0;



	if (obj->programs && obj->nr_programs) {

		for (i = 0; i < obj->nr_programs; i++)
@@ -1251,3 +1248,73 @@ int bpf_program__nth_fd(struct bpf_program *prog, int n) 


	return fd;

}



int bpf_map__get_fd(struct bpf_map *map)

{

	if (!map)

		return -EINVAL;



	return map->fd;

}



int bpf_map__get_def(struct bpf_map *map, struct bpf_map_def *pdef)

{

	if (!map || !pdef)

		return -EINVAL;



	*pdef = map->def;

	return 0;

}



int bpf_map__set_private(struct bpf_map *map, void *priv,

			 bpf_map_clear_priv_t clear_priv)

{

	if (!map)

		return -EINVAL;



	if (map->priv) {

		if (map->clear_priv)

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

	}



	map->priv = priv;

	map->clear_priv = clear_priv;

	return 0;

}



int bpf_map__get_private(struct bpf_map *map, void **ppriv)

{

	if (!map)

		return -EINVAL;



	if (ppriv)

		*ppriv = map->priv;

	return 0;

}



struct bpf_map *

bpf_map__next(struct bpf_map *prev, struct bpf_object *obj)

{

	size_t idx;

	struct bpf_map *s, *e;



	if (!obj || !obj->maps)

		return NULL;



	s = obj->maps;

	e = obj->maps + obj->nr_maps;



	if (prev == NULL)

		return s;



	if ((prev < s) || (prev >= e)) {

		pr_warning("error in %s: map handler doesn't belong to object\n",

			   __func__);

		return NULL;

	}



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

	if (idx >= obj->nr_maps)

		return NULL;

	return &obj->maps[idx];

}

tools/lib/bpf/libbpf.h

+21 −0
Original line number Diff line number Diff line
@@ -165,4 +165,25 @@ struct bpf_map_def { 
	unsigned int max_entries;

};



/*

 * There is another 'struct bpf_map' in include/linux/map.h. However,

 * it is not a uapi header so no need to consider name clash.

 */

struct bpf_map;



struct bpf_map *

bpf_map__next(struct bpf_map *map, struct bpf_object *obj);

#define bpf_map__for_each(pos, obj)		\

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

	     (pos) != NULL;				\

	     (pos) = bpf_map__next((pos), (obj)))



int bpf_map__get_fd(struct bpf_map *map);

int bpf_map__get_def(struct bpf_map *map, struct bpf_map_def *pdef);



typedef void (*bpf_map_clear_priv_t)(struct bpf_map *, void *);

int bpf_map__set_private(struct bpf_map *map, void *priv,

			 bpf_map_clear_priv_t clear_priv);

int bpf_map__get_private(struct bpf_map *map, void **ppriv);



#endif