libbpf: Add support to attach to fentry/fexit tracing progs
Teach libbpf to recognize tracing programs types and attach them to fentry/fexit. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20191114185720.1641606-7-ast@kernel.org
This commit is contained in:
parent
1442e2871b
commit
b8c54ea455
|
@ -201,6 +201,8 @@ enum bpf_attach_type {
|
|||
BPF_CGROUP_GETSOCKOPT,
|
||||
BPF_CGROUP_SETSOCKOPT,
|
||||
BPF_TRACE_RAW_TP,
|
||||
BPF_TRACE_FENTRY,
|
||||
BPF_TRACE_FEXIT,
|
||||
__MAX_BPF_ATTACH_TYPE
|
||||
};
|
||||
|
||||
|
|
|
@ -3856,7 +3856,8 @@ 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 int libbpf_attach_btf_id_by_name(const char *name,
|
||||
enum bpf_attach_type attach_type);
|
||||
|
||||
static struct bpf_object *
|
||||
__bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
|
||||
|
@ -3910,7 +3911,6 @@ __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);
|
||||
|
@ -3923,10 +3923,11 @@ __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)
|
||||
err = libbpf_attach_btf_id_by_name(prog->section_name,
|
||||
attach_type);
|
||||
if (err <= 0)
|
||||
goto out;
|
||||
prog->attach_btf_id = btf_id;
|
||||
prog->attach_btf_id = err;
|
||||
}
|
||||
}
|
||||
|
||||
|
@ -4935,6 +4936,10 @@ static const struct {
|
|||
BPF_PROG_SEC("raw_tp/", BPF_PROG_TYPE_RAW_TRACEPOINT),
|
||||
BPF_PROG_BTF("tp_btf/", BPF_PROG_TYPE_TRACING,
|
||||
BPF_TRACE_RAW_TP),
|
||||
BPF_PROG_BTF("fentry/", BPF_PROG_TYPE_TRACING,
|
||||
BPF_TRACE_FENTRY),
|
||||
BPF_PROG_BTF("fexit/", BPF_PROG_TYPE_TRACING,
|
||||
BPF_TRACE_FEXIT),
|
||||
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),
|
||||
|
@ -5052,43 +5057,56 @@ int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
|
|||
}
|
||||
|
||||
#define BTF_PREFIX "btf_trace_"
|
||||
static int libbpf_attach_btf_id_by_name(const char *name, __u32 *btf_id)
|
||||
int libbpf_find_vmlinux_btf_id(const char *name,
|
||||
enum bpf_attach_type attach_type)
|
||||
{
|
||||
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;
|
||||
char raw_tp_btf[128] = BTF_PREFIX;
|
||||
char *dst = raw_tp_btf + sizeof(BTF_PREFIX) - 1;
|
||||
const char *btf_name;
|
||||
int err = -EINVAL;
|
||||
u32 kind;
|
||||
|
||||
if (IS_ERR(btf)) {
|
||||
pr_warn("vmlinux BTF is not found\n");
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
if (attach_type == BPF_TRACE_RAW_TP) {
|
||||
/* prepend "btf_trace_" prefix per kernel convention */
|
||||
strncat(dst, name, sizeof(raw_tp_btf) - sizeof(BTF_PREFIX));
|
||||
btf_name = raw_tp_btf;
|
||||
kind = BTF_KIND_TYPEDEF;
|
||||
} else {
|
||||
btf_name = name;
|
||||
kind = BTF_KIND_FUNC;
|
||||
}
|
||||
err = btf__find_by_name_kind(btf, btf_name, kind);
|
||||
btf__free(btf);
|
||||
return err;
|
||||
}
|
||||
|
||||
static int libbpf_attach_btf_id_by_name(const char *name,
|
||||
enum bpf_attach_type attach_type)
|
||||
{
|
||||
int i, err;
|
||||
|
||||
if (!name)
|
||||
goto out;
|
||||
return -EINVAL;
|
||||
|
||||
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;
|
||||
err = libbpf_find_vmlinux_btf_id(name + section_names[i].len,
|
||||
attach_type);
|
||||
if (err <= 0)
|
||||
pr_warn("%s is not found in vmlinux BTF\n", name);
|
||||
return err;
|
||||
}
|
||||
pr_warn("failed to identify btf_id based on ELF section name '%s'\n", name);
|
||||
err = -ESRCH;
|
||||
out:
|
||||
btf__free(btf);
|
||||
return err;
|
||||
return -ESRCH;
|
||||
}
|
||||
|
||||
int libbpf_attach_type_by_name(const char *name,
|
||||
|
@ -5716,6 +5734,37 @@ struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
|
|||
return (struct bpf_link *)link;
|
||||
}
|
||||
|
||||
struct bpf_link *bpf_program__attach_trace(struct bpf_program *prog)
|
||||
{
|
||||
char errmsg[STRERR_BUFSIZE];
|
||||
struct bpf_link_fd *link;
|
||||
int prog_fd, pfd;
|
||||
|
||||
prog_fd = bpf_program__fd(prog);
|
||||
if (prog_fd < 0) {
|
||||
pr_warn("program '%s': can't attach before loaded\n",
|
||||
bpf_program__title(prog, false));
|
||||
return ERR_PTR(-EINVAL);
|
||||
}
|
||||
|
||||
link = malloc(sizeof(*link));
|
||||
if (!link)
|
||||
return ERR_PTR(-ENOMEM);
|
||||
link->link.destroy = &bpf_link__destroy_fd;
|
||||
|
||||
pfd = bpf_raw_tracepoint_open(NULL, prog_fd);
|
||||
if (pfd < 0) {
|
||||
pfd = -errno;
|
||||
free(link);
|
||||
pr_warn("program '%s': failed to attach to trace: %s\n",
|
||||
bpf_program__title(prog, false),
|
||||
libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
|
||||
return ERR_PTR(pfd);
|
||||
}
|
||||
link->fd = pfd;
|
||||
return (struct bpf_link *)link;
|
||||
}
|
||||
|
||||
enum bpf_perf_event_ret
|
||||
bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size,
|
||||
void **copy_mem, size_t *copy_size,
|
||||
|
|
|
@ -188,6 +188,8 @@ libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
|
|||
enum bpf_attach_type *expected_attach_type);
|
||||
LIBBPF_API int libbpf_attach_type_by_name(const char *name,
|
||||
enum bpf_attach_type *attach_type);
|
||||
LIBBPF_API int libbpf_find_vmlinux_btf_id(const char *name,
|
||||
enum bpf_attach_type attach_type);
|
||||
|
||||
/* Accessors of bpf_program */
|
||||
struct bpf_program;
|
||||
|
@ -251,6 +253,8 @@ LIBBPF_API struct bpf_link *
|
|||
bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
|
||||
const char *tp_name);
|
||||
|
||||
LIBBPF_API struct bpf_link *
|
||||
bpf_program__attach_trace(struct bpf_program *prog);
|
||||
struct bpf_insn;
|
||||
|
||||
/*
|
||||
|
|
|
@ -199,10 +199,12 @@ LIBBPF_0.0.6 {
|
|||
bpf_map__set_pin_path;
|
||||
bpf_object__open_file;
|
||||
bpf_object__open_mem;
|
||||
bpf_program__attach_trace;
|
||||
bpf_program__get_expected_attach_type;
|
||||
bpf_program__get_type;
|
||||
bpf_program__is_tracing;
|
||||
bpf_program__set_tracing;
|
||||
bpf_program__size;
|
||||
btf__find_by_name_kind;
|
||||
libbpf_find_vmlinux_btf_id;
|
||||
} LIBBPF_0.0.5;
|
||||
|
|
Loading…
Reference in a new issue