[PATCH v5 bpf-next 16/21] libbpf: Introduce bpf_map__initial_value().

[Alexei Starovoitov <alexei.starovoitov@gmail.com>]

From: Alexei Starovoitov <ast@kernel.org>

Introduce bpf_map__initial_value() to read initial contents
of rodata/bss maps. Note only mmaped maps qualify.
Just as bpf_map__set_initial_value() works only for mmaped kconfig.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 tools/lib/bpf/libbpf.c   | 8 ++++++++
 tools/lib/bpf/libbpf.h   | 1 +
 tools/lib/bpf/libbpf.map | 1 +
 3 files changed, 10 insertions(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 8fd70f0592ad..8d3b136c6b29 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -9736,6 +9736,14 @@ int bpf_map__set_initial_value(struct bpf_map *map,
 	return 0;
 }
 
+const void *bpf_map__initial_value(struct bpf_map *map, size_t *psize)
+{
+	if (!map->mmaped)
+		return NULL;
+	*psize = map->def.value_size;
+	return map->mmaped;
+}
+
 bool bpf_map__is_offload_neutral(const struct bpf_map *map)
 {
 	return map->def.type == BPF_MAP_TYPE_PERF_EVENT_ARRAY;
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 8cf168f3717c..a50eab5fec0a 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -471,6 +471,7 @@ LIBBPF_API int bpf_map__set_priv(struct bpf_map *map, void *priv,
 LIBBPF_API void *bpf_map__priv(const struct bpf_map *map);
 LIBBPF_API int bpf_map__set_initial_value(struct bpf_map *map,
 					  const void *data, size_t size);
+LIBBPF_API const void *bpf_map__initial_value(struct bpf_map *map, size_t *psize);
 LIBBPF_API bool bpf_map__is_offload_neutral(const struct bpf_map *map);
 LIBBPF_API bool bpf_map__is_internal(const struct bpf_map *map);
 LIBBPF_API int bpf_map__set_pin_path(struct bpf_map *map, const char *path);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 889ee2f3611c..dd0f24370939 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -359,6 +359,7 @@ LIBBPF_0.4.0 {
 		bpf_linker__finalize;
 		bpf_linker__free;
 		bpf_linker__new;
+		bpf_map__initial_value;
 		bpf_map__inner_map;
 		bpf_object__gen_loader;
 		bpf_object__set_kversion;
-- 
2.30.2