[PATCH bpf-next 3/6] libbpf: add bpf_object__load_xattr() API function to pass log_level

[Quentin Monnet <quentin.monnet@netronome.com>]

libbpf was recently made aware of the log_level attribute for programs,
used to specify the level of information expected to be dumped by the
verifier.

Create an API function to pass additional attributes when loading a
bpf_object, so we can set this log_level value in programs when loading
them, and so that so that applications relying on libbpf but not calling
bpf_prog_load_xattr() can also use that feature.

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
---
 tools/lib/bpf/libbpf.c   | 20 +++++++++++++++++---
 tools/lib/bpf/libbpf.h   |  6 ++++++
 tools/lib/bpf/libbpf.map |  1 +
 3 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 11a65db4b93f..9bba86404e65 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2095,7 +2095,7 @@ static bool bpf_program__is_function_storage(struct bpf_program *prog,
 }
 
 static int
-bpf_object__load_progs(struct bpf_object *obj)
+bpf_object__load_progs(struct bpf_object *obj, int log_level)
 {
 	size_t i;
 	int err;
@@ -2103,6 +2103,7 @@ bpf_object__load_progs(struct bpf_object *obj)
 	for (i = 0; i < obj->nr_programs; i++) {
 		if (bpf_program__is_function_storage(&obj->programs[i], obj))
 			continue;
+		obj->programs[i].log_level = log_level;
 		err = bpf_program__load(&obj->programs[i],
 					obj->license,
 					obj->kern_version);
@@ -2254,10 +2255,14 @@ int bpf_object__unload(struct bpf_object *obj)
 	return 0;
 }
 
-int bpf_object__load(struct bpf_object *obj)
+int bpf_object__load_xattr(struct bpf_object_load_attr *attr)
 {
+	struct bpf_object *obj;
 	int err;
 
+	if (!attr)
+		return -EINVAL;
+	obj = attr->obj;
 	if (!obj)
 		return -EINVAL;
 
@@ -2270,7 +2275,7 @@ int bpf_object__load(struct bpf_object *obj)
 
 	CHECK_ERR(bpf_object__create_maps(obj), err, out);
 	CHECK_ERR(bpf_object__relocate(obj), err, out);
-	CHECK_ERR(bpf_object__load_progs(obj), err, out);
+	CHECK_ERR(bpf_object__load_progs(obj, attr->log_level), err, out);
 
 	return 0;
 out:
@@ -2279,6 +2284,15 @@ int bpf_object__load(struct bpf_object *obj)
 	return err;
 }
 
+int bpf_object__load(struct bpf_object *obj)
+{
+	struct bpf_object_load_attr attr = {
+		.obj = obj,
+	};
+
+	return bpf_object__load_xattr(&attr);
+}
+
 static int check_path(const char *path)
 {
 	char *cp, errmsg[STRERR_BUFSIZE];
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index c5ff00515ce7..e1c748db44f6 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -89,8 +89,14 @@ LIBBPF_API int bpf_object__unpin_programs(struct bpf_object *obj,
 LIBBPF_API int bpf_object__pin(struct bpf_object *object, const char *path);
 LIBBPF_API void bpf_object__close(struct bpf_object *object);
 
+struct bpf_object_load_attr {
+	struct bpf_object *obj;
+	int log_level;
+};
+
 /* Load/unload object into/from kernel */
 LIBBPF_API int bpf_object__load(struct bpf_object *obj);
+LIBBPF_API int bpf_object__load_xattr(struct bpf_object_load_attr *attr);
 LIBBPF_API int bpf_object__unload(struct bpf_object *obj);
 LIBBPF_API const char *bpf_object__name(struct bpf_object *obj);
 LIBBPF_API unsigned int bpf_object__kversion(struct bpf_object *obj);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 673001787cba..d2d52c8641d2 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -162,5 +162,6 @@ LIBBPF_0.0.3 {
 	global:
 		bpf_map__is_internal;
 		bpf_map_freeze;
+		bpf_object__load_xattr;
 		btf__finalize_data;
 } LIBBPF_0.0.2;
-- 
2.17.1