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

Signed-off-by: Andrii Nakryiko <redacted>
Acked-by: Song Liu <redacted>
---
  tools/lib/bpf/libbpf.c   | 37 +++++++++++++++++++++++++++++++++++++
  tools/lib/bpf/libbpf.h   |  3 +++
  tools/lib/bpf/libbpf.map |  1 +
  3 files changed, 41 insertions(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 8ad4f915df38..f8c7a7ecb35e 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c

@@ -4263,6 +4263,43 @@ 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));
+	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,

diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 60611f4b4e1d..f55933784f95 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h

@@ -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;
  

diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 3c618b75ef65..e6b7d4edbc93 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map

@@ -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;