1 files changed, 28 insertions, 6 deletions

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 4ccfae30e681..17bc922f543f 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -498,6 +498,10 @@ struct bpf_object {
 	 * it at load time.
 	 */
 	struct btf *btf_vmlinux;
+	/* Path to the custom BTF to be used for BPF CO-RE relocations as an
+	 * override for vmlinux BTF.
+	 */
+	char *btf_custom_path;
 	/* vmlinux BTF override for CO-RE relocations */
 	struct btf *btf_vmlinux_override;
 	/* Lazily initialized kernel module BTFs */
@@ -2645,8 +2649,10 @@ static bool obj_needs_vmlinux_btf(const struct bpf_object *obj)
 	struct bpf_program *prog;
 	int i;
 
-	/* CO-RE relocations need kernel BTF */
-	if (obj->btf_ext && obj->btf_ext->core_relo_info.len)
+	/* CO-RE relocations need kernel BTF, only when btf_custom_path
+	 * is not specified
+	 */
+	if (obj->btf_ext && obj->btf_ext->core_relo_info.len && !obj->btf_custom_path)
 		return true;
 
 	/* Support for typed ksyms needs kernel BTF */
@@ -7596,7 +7602,7 @@ static struct bpf_object *
 __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
 		   const struct bpf_object_open_opts *opts)
 {
-	const char *obj_name, *kconfig;
+	const char *obj_name, *kconfig, *btf_tmp_path;
 	struct bpf_program *prog;
 	struct bpf_object *obj;
 	char tmp_name[64];
@@ -7627,11 +7633,26 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
 	if (IS_ERR(obj))
 		return obj;
 
+	btf_tmp_path = OPTS_GET(opts, btf_custom_path, NULL);
+	if (btf_tmp_path) {
+		if (strlen(btf_tmp_path) >= PATH_MAX) {
+			err = -ENAMETOOLONG;
+			goto out;
+		}
+		obj->btf_custom_path = strdup(btf_tmp_path);
+		if (!obj->btf_custom_path) {
+			err = -ENOMEM;
+			goto out;
+		}
+	}
+
 	kconfig = OPTS_GET(opts, kconfig, NULL);
 	if (kconfig) {
 		obj->kconfig = strdup(kconfig);
-		if (!obj->kconfig)
-			return ERR_PTR(-ENOMEM);
+		if (!obj->kconfig) {
+			err = -ENOMEM;
+			goto out;
+		}
 	}
 
 	err = bpf_object__elf_init(obj);
@@ -8097,7 +8118,7 @@ int bpf_object__load_xattr(struct bpf_object_load_attr *attr)
 	err = err ? : bpf_object__sanitize_maps(obj);
 	err = err ? : bpf_object__init_kern_struct_ops_maps(obj);
 	err = err ? : bpf_object__create_maps(obj);
-	err = err ? : bpf_object__relocate(obj, attr->target_btf_path);
+	err = err ? : bpf_object__relocate(obj, obj->btf_custom_path ? : attr->target_btf_path);
 	err = err ? : bpf_object__load_progs(obj, attr->log_level);
 
 	if (obj->gen_loader) {
@@ -8744,6 +8765,7 @@ void bpf_object__close(struct bpf_object *obj)
 	for (i = 0; i < obj->nr_maps; i++)
 		bpf_map__destroy(&obj->maps[i]);
 
+	zfree(&obj->btf_custom_path);
 	zfree(&obj->kconfig);
 	zfree(&obj->externs);
 	obj->nr_extern = 0;