libbpf: Add bpf_object__unpin()

For bpf_object__pin_programs() there is bpf_object__unpin_programs().
Likewise bpf_object__unpin_maps() for bpf_object__pin_maps().

But no bpf_object__unpin() for bpf_object__pin(). Adding the former adds
symmetry to the API.

It's also convenient for cleanup in application code. It's an API I
would've used if it was available for a repro I was writing earlier.

Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/bpf/b2f9d41da4a350281a0b53a804d11b68327e14e5.1692832478.git.dxu@dxuuu.xyz

tools/lib/bpf/libbpf.c

@@ -8376,6 +8376,21 @@ int bpf_object__pin(struct bpf_object *obj, const char *path)
 	return 0;
 }
 
+int bpf_object__unpin(struct bpf_object *obj, const char *path)
+{
+	int err;
+
+	err = bpf_object__unpin_programs(obj, path);
+	if (err)
+		return libbpf_err(err);
+
+	err = bpf_object__unpin_maps(obj, path);
+	if (err)
+		return libbpf_err(err);
+
+	return 0;
+}
+
 static void bpf_map__destroy(struct bpf_map *map)
 {
 	if (map->inner_map) {

tools/lib/bpf/libbpf.h

@@ -266,6 +266,7 @@ LIBBPF_API int bpf_object__pin_programs(struct bpf_object *obj,
 LIBBPF_API int bpf_object__unpin_programs(struct bpf_object *obj,
 					  const char *path);
 LIBBPF_API int bpf_object__pin(struct bpf_object *object, const char *path);
+LIBBPF_API int bpf_object__unpin(struct bpf_object *object, const char *path);
 
 LIBBPF_API const char *bpf_object__name(const struct bpf_object *obj);
 LIBBPF_API unsigned int bpf_object__kversion(const struct bpf_object *obj);

tools/lib/bpf/libbpf.map

@@ -395,6 +395,7 @@ LIBBPF_1.2.0 {
 LIBBPF_1.3.0 {
 	global:
 		bpf_obj_pin_opts;
+		bpf_object__unpin;
 		bpf_prog_detach_opts;
 		bpf_program__attach_netfilter;
 		bpf_program__attach_tcx;