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>
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 7e9c801..1354cc9 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);
+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);
-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 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);
