Commit 5532dfd4 authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Alexei Starovoitov
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libbpf: Simplify BPF program auto-attach code 



Remove the need to explicitly pass bpf_sec_def for auto-attachable BPF
programs, as it is already recorded at bpf_object__open() time for all
recognized type of BPF programs. This further reduces number of explicit
calls to find_sec_def(), simplifying further refactorings.

No functional changes are done by this patch.

Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20210914014733.2768-4-andrii@kernel.org
parent 91b4d1d1

tools/lib/bpf/libbpf.c

+22 −39
Original line number Diff line number Diff line
@@ -218,8 +218,7 @@ struct reloc_desc { 


struct bpf_sec_def;



typedef struct bpf_link *(*attach_fn_t)(const struct bpf_sec_def *sec,

					struct bpf_program *prog);

typedef struct bpf_link *(*attach_fn_t)(struct bpf_program *prog);



struct bpf_sec_def {

	const char *sec;
@@ -7920,18 +7919,12 @@ void bpf_program__set_expected_attach_type(struct bpf_program *prog, 
	__VA_ARGS__							    \

}



static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec,

				      struct bpf_program *prog);

static struct bpf_link *attach_tp(const struct bpf_sec_def *sec,

				  struct bpf_program *prog);

static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec,

				      struct bpf_program *prog);

static struct bpf_link *attach_trace(const struct bpf_sec_def *sec,

				     struct bpf_program *prog);

static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec,

				   struct bpf_program *prog);

static struct bpf_link *attach_iter(const struct bpf_sec_def *sec,

				    struct bpf_program *prog);

static struct bpf_link *attach_kprobe(struct bpf_program *prog);

static struct bpf_link *attach_tp(struct bpf_program *prog);

static struct bpf_link *attach_raw_tp(struct bpf_program *prog);

static struct bpf_link *attach_trace(struct bpf_program *prog);

static struct bpf_link *attach_lsm(struct bpf_program *prog);

static struct bpf_link *attach_iter(struct bpf_program *prog);



static const struct bpf_sec_def section_defs[] = {

	BPF_PROG_SEC("socket",			BPF_PROG_TYPE_SOCKET_FILTER),
@@ -9391,8 +9384,7 @@ struct bpf_link *bpf_program__attach_kprobe(struct bpf_program *prog, 
	return bpf_program__attach_kprobe_opts(prog, func_name, &opts);

}



static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec,

				      struct bpf_program *prog)

static struct bpf_link *attach_kprobe(struct bpf_program *prog)

{

	DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, opts);

	unsigned long offset = 0;
@@ -9401,8 +9393,8 @@ static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec, 
	char *func;

	int n, err;



	func_name = prog->sec_name + sec->len;

	opts.retprobe = strcmp(sec->sec, "kretprobe/") == 0;

	func_name = prog->sec_name + prog->sec_def->len;

	opts.retprobe = strcmp(prog->sec_def->sec, "kretprobe/") == 0;



	n = sscanf(func_name, "%m[a-zA-Z0-9_.]+%li", &func, &offset);

	if (n < 1) {
@@ -9565,8 +9557,7 @@ struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog, 
	return bpf_program__attach_tracepoint_opts(prog, tp_category, tp_name, NULL);

}



static struct bpf_link *attach_tp(const struct bpf_sec_def *sec,

				  struct bpf_program *prog)

static struct bpf_link *attach_tp(struct bpf_program *prog)

{

	char *sec_name, *tp_cat, *tp_name;

	struct bpf_link *link;
@@ -9576,7 +9567,7 @@ static struct bpf_link *attach_tp(const struct bpf_sec_def *sec, 
		return libbpf_err_ptr(-ENOMEM);



	/* extract "tp/<category>/<name>" */

	tp_cat = sec_name + sec->len;

	tp_cat = sec_name + prog->sec_def->len;

	tp_name = strchr(tp_cat, '/');

	if (!tp_name) {

		free(sec_name);
@@ -9620,10 +9611,9 @@ struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog, 
	return link;

}



static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec,

				      struct bpf_program *prog)

static struct bpf_link *attach_raw_tp(struct bpf_program *prog)

{

	const char *tp_name = prog->sec_name + sec->len;

	const char *tp_name = prog->sec_name + prog->sec_def->len;



	return bpf_program__attach_raw_tracepoint(prog, tp_name);

}
@@ -9668,14 +9658,12 @@ struct bpf_link *bpf_program__attach_lsm(struct bpf_program *prog) 
	return bpf_program__attach_btf_id(prog);

}



static struct bpf_link *attach_trace(const struct bpf_sec_def *sec,

				     struct bpf_program *prog)

static struct bpf_link *attach_trace(struct bpf_program *prog)

{

	return bpf_program__attach_trace(prog);

}



static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec,

				   struct bpf_program *prog)

static struct bpf_link *attach_lsm(struct bpf_program *prog)

{

	return bpf_program__attach_lsm(prog);

}
@@ -9806,21 +9794,17 @@ bpf_program__attach_iter(struct bpf_program *prog, 
	return link;

}



static struct bpf_link *attach_iter(const struct bpf_sec_def *sec,

				    struct bpf_program *prog)

static struct bpf_link *attach_iter(struct bpf_program *prog)

{

	return bpf_program__attach_iter(prog, NULL);

}



struct bpf_link *bpf_program__attach(struct bpf_program *prog)

{

	const struct bpf_sec_def *sec_def;



	sec_def = find_sec_def(prog->sec_name);

	if (!sec_def || !sec_def->attach_fn)

	if (!prog->sec_def || !prog->sec_def->attach_fn)

		return libbpf_err_ptr(-ESRCH);



	return sec_def->attach_fn(sec_def, prog);

	return prog->sec_def->attach_fn(prog);

}



static int bpf_link__detach_struct_ops(struct bpf_link *link)
@@ -10899,16 +10883,15 @@ int bpf_object__attach_skeleton(struct bpf_object_skeleton *s) 
	for (i = 0; i < s->prog_cnt; i++) {

		struct bpf_program *prog = *s->progs[i].prog;

		struct bpf_link **link = s->progs[i].link;

		const struct bpf_sec_def *sec_def;



		if (!prog->load)

			continue;



		sec_def = find_sec_def(prog->sec_name);

		if (!sec_def || !sec_def->attach_fn)

		/* auto-attaching not supported for this program */

		if (!prog->sec_def || !prog->sec_def->attach_fn)

			continue;



		*link = sec_def->attach_fn(sec_def, prog);

		*link = prog->sec_def->attach_fn(prog);

		err = libbpf_get_error(*link);

		if (err) {

			pr_warn("failed to auto-attach program '%s': %d\n",