| /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
| |
| #include "dlfcn-util.h" |
| #include "bpf-dlopen.h" |
| #include "log.h" |
| #include "strv.h" |
| |
| #if HAVE_LIBBPF |
| |
| /* libbpf changed types of function prototypes around, so we need to disable some type checking for older |
| * libbpf. We consider everything older than 0.7 too old for accurate type checks. */ |
| #if defined(__LIBBPF_CURRENT_VERSION_GEQ) |
| #if __LIBBPF_CURRENT_VERSION_GEQ(0, 7) |
| #define MODERN_LIBBPF 1 |
| #endif |
| #endif |
| #if !defined(MODERN_LIBBPF) |
| #define MODERN_LIBBPF 0 |
| #endif |
| |
| struct bpf_link* (*sym_bpf_program__attach_cgroup)(const struct bpf_program *, int); |
| struct bpf_link* (*sym_bpf_program__attach_lsm)(const struct bpf_program *); |
| int (*sym_bpf_link__fd)(const struct bpf_link *); |
| int (*sym_bpf_link__destroy)(struct bpf_link *); |
| int (*sym_bpf_map__fd)(const struct bpf_map *); |
| const char* (*sym_bpf_map__name)(const struct bpf_map *); |
| int (*sym_bpf_map_create)(enum bpf_map_type, const char *, __u32, __u32, __u32, const struct bpf_map_create_opts *); |
| int (*sym_bpf_map__set_max_entries)(struct bpf_map *, __u32); |
| int (*sym_bpf_map_update_elem)(int, const void *, const void *, __u64); |
| int (*sym_bpf_map_delete_elem)(int, const void *); |
| int (*sym_bpf_map__set_inner_map_fd)(struct bpf_map *, int); |
| int (*sym_bpf_object__open_skeleton)(struct bpf_object_skeleton *, const struct bpf_object_open_opts *); |
| int (*sym_bpf_object__load_skeleton)(struct bpf_object_skeleton *); |
| int (*sym_bpf_object__attach_skeleton)(struct bpf_object_skeleton *); |
| void (*sym_bpf_object__detach_skeleton)(struct bpf_object_skeleton *); |
| void (*sym_bpf_object__destroy_skeleton)(struct bpf_object_skeleton *); |
| int (*sym_libbpf_probe_bpf_prog_type)(enum bpf_prog_type, const void *); |
| const char* (*sym_bpf_program__name)(const struct bpf_program *); |
| libbpf_print_fn_t (*sym_libbpf_set_print)(libbpf_print_fn_t); |
| long (*sym_libbpf_get_error)(const void *); |
| |
| /* compat symbols removed in libbpf 1.0 */ |
| int (*sym_bpf_create_map)(enum bpf_map_type, int key_size, int value_size, int max_entries, __u32 map_flags); |
| bool (*sym_bpf_probe_prog_type)(enum bpf_prog_type, __u32); |
| |
| _printf_(2,0) |
| static int bpf_print_func(enum libbpf_print_level level, const char *fmt, va_list ap) { |
| #if !LOG_TRACE |
| /* libbpf logs a lot of details at its debug level, which we don't need to see. */ |
| if (level == LIBBPF_DEBUG) |
| return 0; |
| #endif |
| /* All other levels are downgraded to LOG_DEBUG */ |
| |
| /* errno is used here, on the assumption that if the log message uses %m, errno will be set to |
| * something useful. Otherwise, it shouldn't matter, we may pass 0 or some bogus value. */ |
| return log_internalv(LOG_DEBUG, errno, NULL, 0, NULL, fmt, ap); |
| } |
| |
| int dlopen_bpf(void) { |
| void *dl; |
| int r; |
| |
| DISABLE_WARNING_DEPRECATED_DECLARATIONS; |
| |
| dl = dlopen("libbpf.so.1", RTLD_LAZY); |
| if (!dl) { |
| /* libbpf < 1.0.0 (we rely on 0.1.0+) provide most symbols we care about, but |
| * unfortunately not all until 0.7.0. See bpf-compat.h for more details. |
| * Once we consider we can assume 0.7+ is present we can just use the same symbol |
| * list for both files, and when we assume 1.0+ is present we can remove this dlopen */ |
| dl = dlopen("libbpf.so.0", RTLD_LAZY); |
| if (!dl) |
| return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), |
| "neither libbpf.so.1 nor libbpf.so.0 are installed: %s", dlerror()); |
| |
| /* symbols deprecated in 1.0 we use as compat */ |
| r = dlsym_many_or_warn( |
| dl, LOG_DEBUG, |
| #if MODERN_LIBBPF |
| /* Don't exist anymore in new libbpf, hence cannot type check them */ |
| DLSYM_ARG_FORCE(bpf_create_map), |
| DLSYM_ARG_FORCE(bpf_probe_prog_type)); |
| #else |
| DLSYM_ARG(bpf_create_map), |
| DLSYM_ARG(bpf_probe_prog_type)); |
| #endif |
| } else { |
| /* symbols available from 0.7.0 */ |
| r = dlsym_many_or_warn( |
| dl, LOG_DEBUG, |
| #if MODERN_LIBBPF |
| DLSYM_ARG(bpf_map_create), |
| DLSYM_ARG(libbpf_probe_bpf_prog_type) |
| #else |
| /* These symbols did not exist in old libbpf, hence we cannot type check them */ |
| DLSYM_ARG_FORCE(bpf_map_create), |
| DLSYM_ARG_FORCE(libbpf_probe_bpf_prog_type) |
| #endif |
| ); |
| } |
| |
| r = dlsym_many_or_warn( |
| dl, LOG_DEBUG, |
| DLSYM_ARG(bpf_link__destroy), |
| DLSYM_ARG(bpf_link__fd), |
| DLSYM_ARG(bpf_map__fd), |
| DLSYM_ARG(bpf_map__name), |
| DLSYM_ARG(bpf_map__set_max_entries), |
| DLSYM_ARG(bpf_map_update_elem), |
| DLSYM_ARG(bpf_map_delete_elem), |
| DLSYM_ARG(bpf_map__set_inner_map_fd), |
| DLSYM_ARG(bpf_object__open_skeleton), |
| DLSYM_ARG(bpf_object__load_skeleton), |
| DLSYM_ARG(bpf_object__attach_skeleton), |
| DLSYM_ARG(bpf_object__detach_skeleton), |
| DLSYM_ARG(bpf_object__destroy_skeleton), |
| #if MODERN_LIBBPF |
| DLSYM_ARG(bpf_program__attach_cgroup), |
| DLSYM_ARG(bpf_program__attach_lsm), |
| #else |
| /* libbpf added a "const" to function parameters where it should not have, ignore this type incompatibility */ |
| DLSYM_ARG_FORCE(bpf_program__attach_cgroup), |
| DLSYM_ARG_FORCE(bpf_program__attach_lsm), |
| #endif |
| DLSYM_ARG(bpf_program__name), |
| DLSYM_ARG(libbpf_set_print), |
| DLSYM_ARG(libbpf_get_error)); |
| if (r < 0) |
| return r; |
| |
| /* We set the print helper unconditionally. Otherwise libbpf will emit not useful log messages. */ |
| (void) sym_libbpf_set_print(bpf_print_func); |
| |
| REENABLE_WARNING; |
| |
| return r; |
| } |
| |
| #else |
| |
| int dlopen_bpf(void) { |
| return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), |
| "libbpf support is not compiled in."); |
| } |
| #endif |
