[PATCH] libbpf: add bpf object kern_version attribute setter

[Rafael David Tinoco <rafaeldtinoco@xxxxxxxxxx>]

Unfortunately some distros don't have their kernel version defined
accurately in <linux/version.h> due to different long term support
reasons.

It is important to have a way to override the bpf kern_version
attribute during runtime: some old kernels might still check for
kern_version attribute during bpf_prog_load().

Signed-off-by: Rafael David Tinoco <rafaeldtinoco@xxxxxxxxxx>
---
 src/libbpf.c | 15 +++++++++++++++
 src/libbpf.h |  1 +
 2 files changed, 16 insertions(+)

diff --git a/src/libbpf.c b/src/libbpf.c
index 0c4a386..7b52cd6 100644
--- a/src/libbpf.c
+++ b/src/libbpf.c
@@ -8278,6 +8278,21 @@ int bpf_object__btf_fd(const struct bpf_object *obj)
 	return obj->btf ? btf__fd(obj->btf) : -1;
 }
 
+int bpf_object__set_kversion(struct bpf_object *obj, char *kern_version)
+{
+	__u32 major, minor, patch;
+
+	if (!kern_version) {
+		obj->kern_version = 0;
+		return 0;
+	}
+	if (sscanf(kern_version, "%u.%u.%u", &major, &minor, &patch) != 3)
+		return -1;
+	obj->kern_version = KERNEL_VERSION(major, minor, patch);
+
+	return 0;
+}
+
 int bpf_object__set_priv(struct bpf_object *obj, void *priv,
 			 bpf_object_clear_priv_t clear_priv)
 {
diff --git a/src/libbpf.h b/src/libbpf.h
index 3c35eb4..3e14ae7 100644
--- a/src/libbpf.h
+++ b/src/libbpf.h
@@ -143,6 +143,7 @@ LIBBPF_API int bpf_object__unload(struct bpf_object *obj);
 
 LIBBPF_API const char *bpf_object__name(const struct bpf_object *obj);
 LIBBPF_API unsigned int bpf_object__kversion(const struct bpf_object *obj);
+LIBBPF_API int bpf_object__set_kversion(struct bpf_object *obj, char *kern_version);
 
 struct btf;
 LIBBPF_API struct btf *bpf_object__btf(const struct bpf_object *obj);
-- 
2.27.0