[PATCH bpf-next 1/2] libbpf: Implement btf__save_to_file()

["Mauricio Vásquez" <mauricio@kinvolk.io>]

Implement helper function to save the contents of a BTF object to a
file.

Signed-off-by: Mauricio Vásquez <mauricio@kinvolk.io>
Signed-off-by: Rafael David Tinoco <rafael.tinoco@aquasec.com>
Signed-off-by: Lorenzo Fontana <lorenzo.fontana@elastic.co>
---
 tools/lib/bpf/btf.c      | 22 ++++++++++++++++++++++
 tools/lib/bpf/btf.h      |  2 ++
 tools/lib/bpf/libbpf.map |  1 +
 3 files changed, 25 insertions(+)

diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 0c628c33e23b..087035574dba 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -4773,3 +4773,25 @@ int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void
 
 	return 0;
 }
+
+int btf__save_to_file(struct btf *btf, const char *path)
+{
+	const void *data;
+	__u32 data_sz;
+	FILE *file;
+
+	data = btf_get_raw_data(btf, &data_sz, btf->swapped_endian);
+	if (!data)
+		return -ENOMEM;
+
+	file = fopen(path, "wb");
+	if (!file)
+		return -errno;
+
+	if (fwrite(data, 1, data_sz, file) != data_sz) {
+		fclose(file);
+		return -EIO;
+	}
+
+	return fclose(file);
+}
diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
index bc005ba3ceec..300ad498c615 100644
--- a/tools/lib/bpf/btf.h
+++ b/tools/lib/bpf/btf.h
@@ -114,6 +114,8 @@ LIBBPF_API struct btf *btf__parse_elf_split(const char *path, struct btf *base_b
 LIBBPF_API struct btf *btf__parse_raw(const char *path);
 LIBBPF_API struct btf *btf__parse_raw_split(const char *path, struct btf *base_btf);
 
+LIBBPF_API int btf__save_to_file(struct btf *btf, const char *path);
+
 LIBBPF_API struct btf *btf__load_vmlinux_btf(void);
 LIBBPF_API struct btf *btf__load_module_btf(const char *module_name, struct btf *vmlinux_btf);
 LIBBPF_API struct btf *libbpf_find_kernel_btf(void);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 15239c05659c..0e9bed7c9b9e 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -399,4 +399,5 @@ LIBBPF_0.6.0 {
 		btf__add_decl_tag;
 		btf__raw_data;
 		btf__type_cnt;
+		btf__save_to_file;
 } LIBBPF_0.5.0;
-- 
2.25.1