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libbpf: add raw tracepoint attach API

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Add a wrapper utilizing bpf_link "infrastructure" to allow attaching BPF
programs to raw tracepoints.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Andrii Nakryiko 2019-07-01 16:59:00 -07:00 committed by Daniel Borkmann
parent f6de59c17f
commit 84bf5e1f4f
3 changed files with 43 additions and 0 deletions
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39
tools/lib/bpf/libbpf.c
View File

@ -4269,6 +4269,45 @@ struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog,
return link;
}
static int bpf_link__destroy_fd(struct bpf_link *link)
{
struct bpf_link_fd *l = (void *)link;
return close(l->fd);
}
struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
const char *tp_name)
{
char errmsg[STRERR_BUFSIZE];
struct bpf_link_fd *link;
int prog_fd, pfd;
prog_fd = bpf_program__fd(prog);
if (prog_fd < 0) {
pr_warning("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(tp_name, prog_fd);
if (pfd < 0) {
pfd = -errno;
free(link);
pr_warning("program '%s': failed to attach to raw tracepoint '%s': %s\n",
bpf_program__title(prog, false), tp_name,
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,

3
tools/lib/bpf/libbpf.h
View File

@ -182,6 +182,9 @@ LIBBPF_API struct bpf_link *
bpf_program__attach_tracepoint(struct bpf_program *prog,
const char *tp_category,
const char *tp_name);
LIBBPF_API struct bpf_link *
bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
const char *tp_name);
struct bpf_insn;

1
tools/lib/bpf/libbpf.map
View File

@ -171,6 +171,7 @@ LIBBPF_0.0.4 {
bpf_object__load_xattr;
bpf_program__attach_kprobe;
bpf_program__attach_perf_event;
bpf_program__attach_raw_tracepoint;
bpf_program__attach_tracepoint;
bpf_program__attach_uprobe;
btf_dump__dump_type;