libbpf: Per-symbol visibility for DSO

Make global symbols in libbpf DSO hidden by default with
-fvisibility=hidden and export symbols that are part of ABI explicitly
with __attribute__((visibility("default"))).

This is common practice that should prevent from accidentally exporting
a symbol, that is not supposed to be a part of ABI what, in turn,
improves both libbpf developer- and user-experiences. See [1] for more
details.

Export control becomes more important since more and more projects use
libbpf.

The patch doesn't export a bunch of netlink related functions since as
agreed in [2] they'll be reworked. That doesn't break bpftool since
bpftool links libbpf statically.

[1] https://www.akkadia.org/drepper/dsohowto.pdf (2.2 Export Control)
[2] https://www.mail-archive.com/netdev@vger.kernel.org/msg251434.html

Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

4 files changed, 179 insertions, 148 deletions

diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index 79d84413ddf2..425b480bda75 100644
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -125,6 +125,7 @@ override CFLAGS += $(EXTRA_WARNINGS)
 override CFLAGS += -Werror -Wall
 override CFLAGS += -fPIC
 override CFLAGS += $(INCLUDES)
+override CFLAGS += -fvisibility=hidden
 
 ifeq ($(VERBOSE),1)
   Q =
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 69a4d40c4227..258c3c178333 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -27,6 +27,10 @@
 #include <stdbool.h>
 #include <stddef.h>
 
+#ifndef LIBBPF_API
+#define LIBBPF_API __attribute__((visibility("default")))
+#endif
+
 struct bpf_create_map_attr {
 	const char *name;
 	enum bpf_map_type map_type;
@@ -42,21 +46,24 @@ struct bpf_create_map_attr {
 	__u32 inner_map_fd;
 };
 
-int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr);
-int bpf_create_map_node(enum bpf_map_type map_type, const char *name,
-			int key_size, int value_size, int max_entries,
-			__u32 map_flags, int node);
-int bpf_create_map_name(enum bpf_map_type map_type, const char *name,
-			int key_size, int value_size, int max_entries,
-			__u32 map_flags);
-int bpf_create_map(enum bpf_map_type map_type, int key_size, int value_size,
-		   int max_entries, __u32 map_flags);
-int bpf_create_map_in_map_node(enum bpf_map_type map_type, const char *name,
-			       int key_size, int inner_map_fd, int max_entries,
-			       __u32 map_flags, int node);
-int bpf_create_map_in_map(enum bpf_map_type map_type, const char *name,
-			  int key_size, int inner_map_fd, int max_entries,
-			  __u32 map_flags);
+LIBBPF_API int
+bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr);
+LIBBPF_API int bpf_create_map_node(enum bpf_map_type map_type, const char *name,
+				   int key_size, int value_size,
+				   int max_entries, __u32 map_flags, int node);
+LIBBPF_API int bpf_create_map_name(enum bpf_map_type map_type, const char *name,
+				   int key_size, int value_size,
+				   int max_entries, __u32 map_flags);
+LIBBPF_API int bpf_create_map(enum bpf_map_type map_type, int key_size,
+			      int value_size, int max_entries, __u32 map_flags);
+LIBBPF_API int bpf_create_map_in_map_node(enum bpf_map_type map_type,
+					  const char *name, int key_size,
+					  int inner_map_fd, int max_entries,
+					  __u32 map_flags, int node);
+LIBBPF_API int bpf_create_map_in_map(enum bpf_map_type map_type,
+				     const char *name, int key_size,
+				     int inner_map_fd, int max_entries,
+				     __u32 map_flags);
 
 struct bpf_load_program_attr {
 	enum bpf_prog_type prog_type;
@@ -74,44 +81,49 @@ struct bpf_load_program_attr {
 
 /* Recommend log buffer size */
 #define BPF_LOG_BUF_SIZE (256 * 1024)
-int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
-			   char *log_buf, size_t log_buf_sz);
-int bpf_load_program(enum bpf_prog_type type, const struct bpf_insn *insns,
-		     size_t insns_cnt, const char *license,
-		     __u32 kern_version, char *log_buf,
-		     size_t log_buf_sz);
-int bpf_verify_program(enum bpf_prog_type type, const struct bpf_insn *insns,
-		       size_t insns_cnt, int strict_alignment,
-		       const char *license, __u32 kern_version,
-		       char *log_buf, size_t log_buf_sz, int log_level);
+LIBBPF_API int
+bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
+		       char *log_buf, size_t log_buf_sz);
+LIBBPF_API int bpf_load_program(enum bpf_prog_type type,
+				const struct bpf_insn *insns, size_t insns_cnt,
+				const char *license, __u32 kern_version,
+				char *log_buf, size_t log_buf_sz);
+LIBBPF_API int bpf_verify_program(enum bpf_prog_type type,
+				  const struct bpf_insn *insns,
+				  size_t insns_cnt, int strict_alignment,
+				  const char *license, __u32 kern_version,
+				  char *log_buf, size_t log_buf_sz,
+				  int log_level);
 
-int bpf_map_update_elem(int fd, const void *key, const void *value,
-			__u64 flags);
+LIBBPF_API int bpf_map_update_elem(int fd, const void *key, const void *value,
+				   __u64 flags);
 
-int bpf_map_lookup_elem(int fd, const void *key, void *value);
-int bpf_map_delete_elem(int fd, const void *key);
-int bpf_map_get_next_key(int fd, const void *key, void *next_key);
-int bpf_obj_pin(int fd, const char *pathname);
-int bpf_obj_get(const char *pathname);
-int bpf_prog_attach(int prog_fd, int attachable_fd, enum bpf_attach_type type,
-		    unsigned int flags);
-int bpf_prog_detach(int attachable_fd, enum bpf_attach_type type);
-int bpf_prog_detach2(int prog_fd, int attachable_fd, enum bpf_attach_type type);
-int bpf_prog_test_run(int prog_fd, int repeat, void *data, __u32 size,
-		      void *data_out, __u32 *size_out, __u32 *retval,
-		      __u32 *duration);
-int bpf_prog_get_next_id(__u32 start_id, __u32 *next_id);
-int bpf_map_get_next_id(__u32 start_id, __u32 *next_id);
-int bpf_prog_get_fd_by_id(__u32 id);
-int bpf_map_get_fd_by_id(__u32 id);
-int bpf_btf_get_fd_by_id(__u32 id);
-int bpf_obj_get_info_by_fd(int prog_fd, void *info, __u32 *info_len);
-int bpf_prog_query(int target_fd, enum bpf_attach_type type, __u32 query_flags,
-		   __u32 *attach_flags, __u32 *prog_ids, __u32 *prog_cnt);
-int bpf_raw_tracepoint_open(const char *name, int prog_fd);
-int bpf_load_btf(void *btf, __u32 btf_size, char *log_buf, __u32 log_buf_size,
-		 bool do_log);
-int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf, __u32 *buf_len,
-		      __u32 *prog_id, __u32 *fd_type, __u64 *probe_offset,
-		      __u64 *probe_addr);
+LIBBPF_API int bpf_map_lookup_elem(int fd, const void *key, void *value);
+LIBBPF_API int bpf_map_delete_elem(int fd, const void *key);
+LIBBPF_API int bpf_map_get_next_key(int fd, const void *key, void *next_key);
+LIBBPF_API int bpf_obj_pin(int fd, const char *pathname);
+LIBBPF_API int bpf_obj_get(const char *pathname);
+LIBBPF_API int bpf_prog_attach(int prog_fd, int attachable_fd,
+			       enum bpf_attach_type type, unsigned int flags);
+LIBBPF_API int bpf_prog_detach(int attachable_fd, enum bpf_attach_type type);
+LIBBPF_API int bpf_prog_detach2(int prog_fd, int attachable_fd,
+				enum bpf_attach_type type);
+LIBBPF_API int bpf_prog_test_run(int prog_fd, int repeat, void *data,
+				 __u32 size, void *data_out, __u32 *size_out,
+				 __u32 *retval, __u32 *duration);
+LIBBPF_API int bpf_prog_get_next_id(__u32 start_id, __u32 *next_id);
+LIBBPF_API int bpf_map_get_next_id(__u32 start_id, __u32 *next_id);
+LIBBPF_API int bpf_prog_get_fd_by_id(__u32 id);
+LIBBPF_API int bpf_map_get_fd_by_id(__u32 id);
+LIBBPF_API int bpf_btf_get_fd_by_id(__u32 id);
+LIBBPF_API int bpf_obj_get_info_by_fd(int prog_fd, void *info, __u32 *info_len);
+LIBBPF_API int bpf_prog_query(int target_fd, enum bpf_attach_type type,
+			      __u32 query_flags, __u32 *attach_flags,
+			      __u32 *prog_ids, __u32 *prog_cnt);
+LIBBPF_API int bpf_raw_tracepoint_open(const char *name, int prog_fd);
+LIBBPF_API int bpf_load_btf(void *btf, __u32 btf_size, char *log_buf,
+			    __u32 log_buf_size, bool do_log);
+LIBBPF_API int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf,
+				 __u32 *buf_len, __u32 *prog_id, __u32 *fd_type,
+				 __u64 *probe_offset, __u64 *probe_addr);
 #endif /* __LIBBPF_BPF_H */
diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
index 6db5462bb2ef..b77e7080f7e7 100644
--- a/tools/lib/bpf/btf.h
+++ b/tools/lib/bpf/btf.h
@@ -6,6 +6,10 @@
 
 #include <linux/types.h>
 
+#ifndef LIBBPF_API
+#define LIBBPF_API __attribute__((visibility("default")))
+#endif
+
 #define BTF_ELF_SEC ".BTF"
 
 struct btf;
@@ -14,13 +18,15 @@ struct btf_type;
 typedef int (*btf_print_fn_t)(const char *, ...)
 	__attribute__((format(printf, 1, 2)));
 
-void btf__free(struct btf *btf);
-struct btf *btf__new(__u8 *data, __u32 size, btf_print_fn_t err_log);
-__s32 btf__find_by_name(const struct btf *btf, const char *type_name);
-const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 id);
-__s64 btf__resolve_size(const struct btf *btf, __u32 type_id);
-int btf__resolve_type(const struct btf *btf, __u32 type_id);
-int btf__fd(const struct btf *btf);
-const char *btf__name_by_offset(const struct btf *btf, __u32 offset);
+LIBBPF_API void btf__free(struct btf *btf);
+LIBBPF_API struct btf *btf__new(__u8 *data, __u32 size, btf_print_fn_t err_log);
+LIBBPF_API __s32 btf__find_by_name(const struct btf *btf,
+				   const char *type_name);
+LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf,
+						  __u32 id);
+LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id);
+LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id);
+LIBBPF_API int btf__fd(const struct btf *btf);
+LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset);
 
 #endif /* __LIBBPF_BTF_H */
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 7e9c801a9fdd..1354cc9f8cba 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -16,6 +16,10 @@
 #include <sys/types.h>  // for size_t
 #include <linux/bpf.h>
 
+#ifndef LIBBPF_API
+#define LIBBPF_API __attribute__((visibility("default")))
+#endif
+
 enum libbpf_errno {
 	__LIBBPF_ERRNO__START = 4000,
 
@@ -37,7 +41,7 @@ enum libbpf_errno {
 	__LIBBPF_ERRNO__END,
 };
 
-int libbpf_strerror(int err, char *buf, size_t size);
+LIBBPF_API int libbpf_strerror(int err, char *buf, size_t size);
 
 /*
  * __printf is defined in include/linux/compiler-gcc.h. However,
@@ -47,9 +51,9 @@ int libbpf_strerror(int err, char *buf, size_t size);
 typedef int (*libbpf_print_fn_t)(const char *, ...)
 	__attribute__((format(printf, 1, 2)));
 
-void libbpf_set_print(libbpf_print_fn_t warn,
-		      libbpf_print_fn_t info,
-		      libbpf_print_fn_t debug);
+LIBBPF_API void libbpf_set_print(libbpf_print_fn_t warn,
+				 libbpf_print_fn_t info,
+				 libbpf_print_fn_t debug);
 
 /* Hide internal to user */
 struct bpf_object;
@@ -59,27 +63,28 @@ struct bpf_object_open_attr {
 	enum bpf_prog_type prog_type;
 };
 
-struct bpf_object *bpf_object__open(const char *path);
-struct bpf_object *bpf_object__open_xattr(struct bpf_object_open_attr *attr);
+LIBBPF_API struct bpf_object *bpf_object__open(const char *path);
+LIBBPF_API struct bpf_object *
+bpf_object__open_xattr(struct bpf_object_open_attr *attr);
 struct bpf_object *__bpf_object__open_xattr(struct bpf_object_open_attr *attr,
 					    int flags);
-struct bpf_object *bpf_object__open_buffer(void *obj_buf,
-					   size_t obj_buf_sz,
-					   const char *name);
-int bpf_object__pin(struct bpf_object *object, const char *path);
-void bpf_object__close(struct bpf_object *object);
+LIBBPF_API struct bpf_object *bpf_object__open_buffer(void *obj_buf,
+						      size_t obj_buf_sz,
+						      const char *name);
+LIBBPF_API int bpf_object__pin(struct bpf_object *object, const char *path);
+LIBBPF_API void bpf_object__close(struct bpf_object *object);
 
 /* Load/unload object into/from kernel */
-int bpf_object__load(struct bpf_object *obj);
-int bpf_object__unload(struct bpf_object *obj);
-const char *bpf_object__name(struct bpf_object *obj);
-unsigned int bpf_object__kversion(struct bpf_object *obj);
-int bpf_object__btf_fd(const struct bpf_object *obj);
+LIBBPF_API int bpf_object__load(struct bpf_object *obj);
+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);
+LIBBPF_API int bpf_object__btf_fd(const struct bpf_object *obj);
 
-struct bpf_program *
+LIBBPF_API struct bpf_program *
 bpf_object__find_program_by_title(struct bpf_object *obj, const char *title);
 
-struct bpf_object *bpf_object__next(struct bpf_object *prev);
+LIBBPF_API struct bpf_object *bpf_object__next(struct bpf_object *prev);
 #define bpf_object__for_each_safe(pos, tmp)			\
 	for ((pos) = bpf_object__next(NULL),		\
 		(tmp) = bpf_object__next(pos);		\
@@ -87,19 +92,20 @@ struct bpf_object *bpf_object__next(struct bpf_object *prev);
 	     (pos) = (tmp), (tmp) = bpf_object__next(tmp))
 
 typedef void (*bpf_object_clear_priv_t)(struct bpf_object *, void *);
-int bpf_object__set_priv(struct bpf_object *obj, void *priv,
-			 bpf_object_clear_priv_t clear_priv);
-void *bpf_object__priv(struct bpf_object *prog);
+LIBBPF_API int bpf_object__set_priv(struct bpf_object *obj, void *priv,
+				    bpf_object_clear_priv_t clear_priv);
+LIBBPF_API void *bpf_object__priv(struct bpf_object *prog);
 
-int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
-			     enum bpf_attach_type *expected_attach_type);
-int libbpf_attach_type_by_name(const char *name,
-			       enum bpf_attach_type *attach_type);
+LIBBPF_API int
+libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
+			 enum bpf_attach_type *expected_attach_type);
+LIBBPF_API int libbpf_attach_type_by_name(const char *name,
+					  enum bpf_attach_type *attach_type);
 
 /* Accessors of bpf_program */
 struct bpf_program;
-struct bpf_program *bpf_program__next(struct bpf_program *prog,
-				      struct bpf_object *obj);
+LIBBPF_API struct bpf_program *bpf_program__next(struct bpf_program *prog,
+						 struct bpf_object *obj);
 
 #define bpf_object__for_each_program(pos, obj)		\
 	for ((pos) = bpf_program__next(NULL, (obj));	\
@@ -109,21 +115,24 @@ struct bpf_program *bpf_program__next(struct bpf_program *prog,
 typedef void (*bpf_program_clear_priv_t)(struct bpf_program *,
 					 void *);
 
-int bpf_program__set_priv(struct bpf_program *prog, void *priv,
-			  bpf_program_clear_priv_t clear_priv);
+LIBBPF_API int bpf_program__set_priv(struct bpf_program *prog, void *priv,
+				     bpf_program_clear_priv_t clear_priv);
 
-void *bpf_program__priv(struct bpf_program *prog);
-void bpf_program__set_ifindex(struct bpf_program *prog, __u32 ifindex);
+LIBBPF_API void *bpf_program__priv(struct bpf_program *prog);
+LIBBPF_API void bpf_program__set_ifindex(struct bpf_program *prog,
+					 __u32 ifindex);
 
-const char *bpf_program__title(struct bpf_program *prog, bool needs_copy);
+LIBBPF_API const char *bpf_program__title(struct bpf_program *prog,
+					  bool needs_copy);
 
-int bpf_program__load(struct bpf_program *prog, char *license,
-		      __u32 kern_version);
-int bpf_program__fd(struct bpf_program *prog);
-int bpf_program__pin_instance(struct bpf_program *prog, const char *path,
-			      int instance);
-int bpf_program__pin(struct bpf_program *prog, const char *path);
-void bpf_program__unload(struct bpf_program *prog);
+LIBBPF_API int bpf_program__load(struct bpf_program *prog, char *license,
+				 __u32 kern_version);
+LIBBPF_API int bpf_program__fd(struct bpf_program *prog);
+LIBBPF_API int bpf_program__pin_instance(struct bpf_program *prog,
+					 const char *path,
+					 int instance);
+LIBBPF_API int bpf_program__pin(struct bpf_program *prog, const char *path);
+LIBBPF_API void bpf_program__unload(struct bpf_program *prog);
 
 struct bpf_insn;
 
@@ -184,34 +193,36 @@ typedef int (*bpf_program_prep_t)(struct bpf_program *prog, int n,
 				  struct bpf_insn *insns, int insns_cnt,
 				  struct bpf_prog_prep_result *res);
 
-int bpf_program__set_prep(struct bpf_program *prog, int nr_instance,
-			  bpf_program_prep_t prep);
+LIBBPF_API int bpf_program__set_prep(struct bpf_program *prog, int nr_instance,
+				     bpf_program_prep_t prep);
 
-int bpf_program__nth_fd(struct bpf_program *prog, int n);
+LIBBPF_API int bpf_program__nth_fd(struct bpf_program *prog, int n);
 
 /*
  * Adjust type of BPF program. Default is kprobe.
  */
-int bpf_program__set_socket_filter(struct bpf_program *prog);
-int bpf_program__set_tracepoint(struct bpf_program *prog);
-int bpf_program__set_raw_tracepoint(struct bpf_program *prog);
-int bpf_program__set_kprobe(struct bpf_program *prog);
-int bpf_program__set_sched_cls(struct bpf_program *prog);
-int bpf_program__set_sched_act(struct bpf_program *prog);
-int bpf_program__set_xdp(struct bpf_program *prog);
-int bpf_program__set_perf_event(struct bpf_program *prog);
-void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type);
-void bpf_program__set_expected_attach_type(struct bpf_program *prog,
-					   enum bpf_attach_type type);
-
-bool bpf_program__is_socket_filter(struct bpf_program *prog);
-bool bpf_program__is_tracepoint(struct bpf_program *prog);
-bool bpf_program__is_raw_tracepoint(struct bpf_program *prog);
-bool bpf_program__is_kprobe(struct bpf_program *prog);
-bool bpf_program__is_sched_cls(struct bpf_program *prog);
-bool bpf_program__is_sched_act(struct bpf_program *prog);
-bool bpf_program__is_xdp(struct bpf_program *prog);
-bool bpf_program__is_perf_event(struct bpf_program *prog);
+LIBBPF_API int bpf_program__set_socket_filter(struct bpf_program *prog);
+LIBBPF_API int bpf_program__set_tracepoint(struct bpf_program *prog);
+LIBBPF_API int bpf_program__set_raw_tracepoint(struct bpf_program *prog);
+LIBBPF_API int bpf_program__set_kprobe(struct bpf_program *prog);
+LIBBPF_API int bpf_program__set_sched_cls(struct bpf_program *prog);
+LIBBPF_API int bpf_program__set_sched_act(struct bpf_program *prog);
+LIBBPF_API int bpf_program__set_xdp(struct bpf_program *prog);
+LIBBPF_API int bpf_program__set_perf_event(struct bpf_program *prog);
+LIBBPF_API void bpf_program__set_type(struct bpf_program *prog,
+				      enum bpf_prog_type type);
+LIBBPF_API void
+bpf_program__set_expected_attach_type(struct bpf_program *prog,
+				      enum bpf_attach_type type);
+
+LIBBPF_API bool bpf_program__is_socket_filter(struct bpf_program *prog);
+LIBBPF_API bool bpf_program__is_tracepoint(struct bpf_program *prog);
+LIBBPF_API bool bpf_program__is_raw_tracepoint(struct bpf_program *prog);
+LIBBPF_API bool bpf_program__is_kprobe(struct bpf_program *prog);
+LIBBPF_API bool bpf_program__is_sched_cls(struct bpf_program *prog);
+LIBBPF_API bool bpf_program__is_sched_act(struct bpf_program *prog);
+LIBBPF_API bool bpf_program__is_xdp(struct bpf_program *prog);
+LIBBPF_API bool bpf_program__is_perf_event(struct bpf_program *prog);
 
 /*
  * No need for __attribute__((packed)), all members of 'bpf_map_def'
@@ -232,39 +243,39 @@ struct bpf_map_def {
  * so no need to worry about a name clash.
  */
 struct bpf_map;
-struct bpf_map *
+LIBBPF_API struct bpf_map *
 bpf_object__find_map_by_name(struct bpf_object *obj, const char *name);
 
 /*
  * Get bpf_map through the offset of corresponding struct bpf_map_def
  * in the BPF object file.
  */
-struct bpf_map *
+LIBBPF_API struct bpf_map *
 bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset);
 
-struct bpf_map *
+LIBBPF_API struct bpf_map *
 bpf_map__next(struct bpf_map *map, struct bpf_object *obj);
 #define bpf_map__for_each(pos, obj)		\
 	for ((pos) = bpf_map__next(NULL, (obj));	\
 	     (pos) != NULL;				\
 	     (pos) = bpf_map__next((pos), (obj)))
 
-int bpf_map__fd(struct bpf_map *map);
-const struct bpf_map_def *bpf_map__def(struct bpf_map *map);
-const char *bpf_map__name(struct bpf_map *map);
-__u32 bpf_map__btf_key_type_id(const struct bpf_map *map);
-__u32 bpf_map__btf_value_type_id(const struct bpf_map *map);
+LIBBPF_API int bpf_map__fd(struct bpf_map *map);
+LIBBPF_API const struct bpf_map_def *bpf_map__def(struct bpf_map *map);
+LIBBPF_API const char *bpf_map__name(struct bpf_map *map);
+LIBBPF_API __u32 bpf_map__btf_key_type_id(const struct bpf_map *map);
+LIBBPF_API __u32 bpf_map__btf_value_type_id(const struct bpf_map *map);
 
 typedef void (*bpf_map_clear_priv_t)(struct bpf_map *, void *);
-int bpf_map__set_priv(struct bpf_map *map, void *priv,
-		      bpf_map_clear_priv_t clear_priv);
-void *bpf_map__priv(struct bpf_map *map);
-int bpf_map__reuse_fd(struct bpf_map *map, int fd);
-bool bpf_map__is_offload_neutral(struct bpf_map *map);
-void bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex);
-int bpf_map__pin(struct bpf_map *map, const char *path);
+LIBBPF_API int bpf_map__set_priv(struct bpf_map *map, void *priv,
+				 bpf_map_clear_priv_t clear_priv);
+LIBBPF_API void *bpf_map__priv(struct bpf_map *map);
+LIBBPF_API int bpf_map__reuse_fd(struct bpf_map *map, int fd);
+LIBBPF_API bool bpf_map__is_offload_neutral(struct bpf_map *map);
+LIBBPF_API void bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex);
+LIBBPF_API int bpf_map__pin(struct bpf_map *map, const char *path);
 
-long libbpf_get_error(const void *ptr);
+LIBBPF_API long libbpf_get_error(const void *ptr);
 
 struct bpf_prog_load_attr {
 	const char *file;
@@ -273,12 +284,12 @@ struct bpf_prog_load_attr {
 	int ifindex;
 };
 
-int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
-			struct bpf_object **pobj, int *prog_fd);
-int bpf_prog_load(const char *file, enum bpf_prog_type type,
-		  struct bpf_object **pobj, int *prog_fd);
+LIBBPF_API int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
+				   struct bpf_object **pobj, int *prog_fd);
+LIBBPF_API int bpf_prog_load(const char *file, enum bpf_prog_type type,
+			     struct bpf_object **pobj, int *prog_fd);
 
-int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags);
+LIBBPF_API int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags);
 
 enum bpf_perf_event_ret {
 	LIBBPF_PERF_EVENT_DONE	= 0,
@@ -288,10 +299,11 @@ enum bpf_perf_event_ret {
 
 typedef enum bpf_perf_event_ret (*bpf_perf_event_print_t)(void *event,
 							  void *priv);
-int bpf_perf_event_read_simple(void *mem, unsigned long size,
-			       unsigned long page_size,
-			       void **buf, size_t *buf_len,
-			       bpf_perf_event_print_t fn, void *priv);
+LIBBPF_API int bpf_perf_event_read_simple(void *mem, unsigned long size,
+					  unsigned long page_size,
+					  void **buf, size_t *buf_len,
+					  bpf_perf_event_print_t fn,
+					  void *priv);
 
 struct nlattr;
 typedef int (*libbpf_dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb);