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
---
tools/lib/bpf/Makefile | 1 +
tools/lib/bpf/bpf.h| 118 ++
tools/lib/bpf/btf.h| 22 +++--
tools/lib/bpf/libbpf.h | 186 ++---
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
#include
+#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
