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libbpf: Add support for prog_tracing

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Cleanup libbpf from expected_attach_type == attach_btf_id hack
and introduce BPF_PROG_TYPE_TRACING.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191030223212.953010-3-ast@kernel.org
This commit is contained in:
Alexei Starovoitov
2019-10-30 15:32:12 -07:00
committed by Daniel Borkmann
parent f1b9509c2f
commit 12a8654b2e
7 changed files with 71 additions and 28 deletions
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79
tools/lib/bpf/libbpf.c
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@@ -188,6 +188,7 @@ struct bpf_program {
bpf_program_clear_priv_t clear_priv;
enum bpf_attach_type expected_attach_type;
__u32 attach_btf_id;
void *func_info;
__u32 func_info_rec_size;
__u32 func_info_cnt;
@@ -3446,6 +3447,7 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
load_attr.line_info_cnt = prog->line_info_cnt;
load_attr.log_level = prog->log_level;
load_attr.prog_flags = prog->prog_flags;
load_attr.attach_btf_id = prog->attach_btf_id;
retry_load:
log_buf = malloc(log_buf_size);
@@ -3607,6 +3609,8 @@ bpf_object__load_progs(struct bpf_object *obj, int log_level)
return 0;
}
static int libbpf_attach_btf_id_by_name(const char *name, __u32 *btf_id);
static struct bpf_object *
__bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
struct bpf_object_open_opts *opts)
@@ -3656,6 +3660,7 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
bpf_object__for_each_program(prog, obj) {
enum bpf_prog_type prog_type;
enum bpf_attach_type attach_type;
__u32 btf_id;
err = libbpf_prog_type_by_name(prog->section_name, &prog_type,
&attach_type);
@@ -3667,6 +3672,12 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
bpf_program__set_type(prog, prog_type);
bpf_program__set_expected_attach_type(prog, attach_type);
if (prog_type == BPF_PROG_TYPE_TRACING) {
err = libbpf_attach_btf_id_by_name(prog->section_name, &btf_id);
if (err)
goto out;
prog->attach_btf_id = btf_id;
}
}
return obj;
@@ -4518,6 +4529,7 @@ BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
BPF_PROG_TYPE_FNS(raw_tracepoint, BPF_PROG_TYPE_RAW_TRACEPOINT);
BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
BPF_PROG_TYPE_FNS(tracing, BPF_PROG_TYPE_TRACING);
enum bpf_attach_type
bpf_program__get_expected_attach_type(struct bpf_program *prog)
@@ -4546,7 +4558,8 @@ void bpf_program__set_expected_attach_type(struct bpf_program *prog,
BPF_PROG_SEC_IMPL(string, ptype, eatype, 1, 0, eatype)
/* Programs that use BTF to identify attach point */
#define BPF_PROG_BTF(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, 0, 1, 0)
#define BPF_PROG_BTF(string, ptype, eatype) \
BPF_PROG_SEC_IMPL(string, ptype, eatype, 0, 1, 0)
/* Programs that can be attached but attach type can't be identified by section
* name. Kept for backward compatibility.
@@ -4573,7 +4586,8 @@ static const struct {
BPF_PROG_SEC("tp/", BPF_PROG_TYPE_TRACEPOINT),
BPF_PROG_SEC("raw_tracepoint/", BPF_PROG_TYPE_RAW_TRACEPOINT),
BPF_PROG_SEC("raw_tp/", BPF_PROG_TYPE_RAW_TRACEPOINT),
BPF_PROG_BTF("tp_btf/", BPF_PROG_TYPE_RAW_TRACEPOINT),
BPF_PROG_BTF("tp_btf/", BPF_PROG_TYPE_TRACING,
BPF_TRACE_RAW_TP),
BPF_PROG_SEC("xdp", BPF_PROG_TYPE_XDP),
BPF_PROG_SEC("perf_event", BPF_PROG_TYPE_PERF_EVENT),
BPF_PROG_SEC("lwt_in", BPF_PROG_TYPE_LWT_IN),
@@ -4678,27 +4692,6 @@ int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
continue;
*prog_type = section_names[i].prog_type;
*expected_attach_type = section_names[i].expected_attach_type;
if (section_names[i].is_attach_btf) {
struct btf *btf = bpf_core_find_kernel_btf();
char raw_tp_btf_name[128] = "btf_trace_";
char *dst = raw_tp_btf_name + sizeof("btf_trace_") - 1;
int ret;
if (IS_ERR(btf)) {
pr_warn("vmlinux BTF is not found\n");
return -EINVAL;
}
/* prepend "btf_trace_" prefix per kernel convention */
strncat(dst, name + section_names[i].len,
sizeof(raw_tp_btf_name) - sizeof("btf_trace_"));
ret = btf__find_by_name(btf, raw_tp_btf_name);
btf__free(btf);
if (ret <= 0) {
pr_warn("%s is not found in vmlinux BTF\n", dst);
return -EINVAL;
}
*expected_attach_type = ret;
}
return 0;
}
pr_warn("failed to guess program type based on ELF section name '%s'\n", name);
@@ -4711,6 +4704,46 @@ int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
return -ESRCH;
}
#define BTF_PREFIX "btf_trace_"
static int libbpf_attach_btf_id_by_name(const char *name, __u32 *btf_id)
{
struct btf *btf = bpf_core_find_kernel_btf();
char raw_tp_btf_name[128] = BTF_PREFIX;
char *dst = raw_tp_btf_name + sizeof(BTF_PREFIX) - 1;
int ret, i, err = -EINVAL;
if (IS_ERR(btf)) {
pr_warn("vmlinux BTF is not found\n");
return -EINVAL;
}
if (!name)
goto out;
for (i = 0; i < ARRAY_SIZE(section_names); i++) {
if (!section_names[i].is_attach_btf)
continue;
if (strncmp(name, section_names[i].sec, section_names[i].len))
continue;
/* prepend "btf_trace_" prefix per kernel convention */
strncat(dst, name + section_names[i].len,
sizeof(raw_tp_btf_name) - sizeof(BTF_PREFIX));
ret = btf__find_by_name(btf, raw_tp_btf_name);
if (ret <= 0) {
pr_warn("%s is not found in vmlinux BTF\n", dst);
goto out;
}
*btf_id = ret;
err = 0;
goto out;
}
pr_warn("failed to identify btf_id based on ELF section name '%s'\n", name);
err = -ESRCH;
out:
btf__free(btf);
return err;
}
int libbpf_attach_type_by_name(const char *name,
enum bpf_attach_type *attach_type)
{