1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 /* Copyright (C) 2019 Facebook */
11 #include <linux/err.h>
17 #include <bpf/libbpf.h>
18 #include <bpf/libbpf_internal.h>
19 #include <sys/types.h>
24 #include "json_writer.h"
27 #define MAX_OBJ_NAME_LEN 64
29 static void sanitize_identifier(char *name)
33 for (i = 0; name[i]; i++)
34 if (!isalnum(name[i]) && name[i] != '_')
38 static bool str_has_prefix(const char *str, const char *prefix)
40 return strncmp(str, prefix, strlen(prefix)) == 0;
43 static bool str_has_suffix(const char *str, const char *suffix)
45 size_t i, n1 = strlen(str), n2 = strlen(suffix);
50 for (i = 0; i < n2; i++) {
51 if (str[n1 - i - 1] != suffix[n2 - i - 1])
58 static const struct btf_type *
59 resolve_func_ptr(const struct btf *btf, __u32 id, __u32 *res_id)
61 const struct btf_type *t;
63 t = skip_mods_and_typedefs(btf, id, NULL);
67 t = skip_mods_and_typedefs(btf, t->type, res_id);
69 return btf_is_func_proto(t) ? t : NULL;
72 static void get_obj_name(char *name, const char *file)
74 char file_copy[PATH_MAX];
76 /* Using basename() POSIX version to be more portable. */
77 strncpy(file_copy, file, PATH_MAX - 1)[PATH_MAX - 1] = '\0';
78 strncpy(name, basename(file_copy), MAX_OBJ_NAME_LEN - 1)[MAX_OBJ_NAME_LEN - 1] = '\0';
79 if (str_has_suffix(name, ".o"))
80 name[strlen(name) - 2] = '\0';
81 sanitize_identifier(name);
84 static void get_header_guard(char *guard, const char *obj_name, const char *suffix)
88 sprintf(guard, "__%s_%s__", obj_name, suffix);
89 for (i = 0; guard[i]; i++)
90 guard[i] = toupper(guard[i]);
93 static bool get_map_ident(const struct bpf_map *map, char *buf, size_t buf_sz)
95 static const char *sfxs[] = { ".data", ".rodata", ".bss", ".kconfig" };
96 const char *name = bpf_map__name(map);
99 if (!bpf_map__is_internal(map)) {
100 snprintf(buf, buf_sz, "%s", name);
104 for (i = 0, n = ARRAY_SIZE(sfxs); i < n; i++) {
105 const char *sfx = sfxs[i], *p;
107 p = strstr(name, sfx);
109 snprintf(buf, buf_sz, "%s", p + 1);
110 sanitize_identifier(buf);
118 static bool get_datasec_ident(const char *sec_name, char *buf, size_t buf_sz)
120 static const char *pfxs[] = { ".data", ".rodata", ".bss", ".kconfig" };
123 /* recognize hard coded LLVM section name */
124 if (strcmp(sec_name, ".arena.1") == 0) {
125 /* this is the name to use in skeleton */
126 snprintf(buf, buf_sz, "arena");
129 for (i = 0, n = ARRAY_SIZE(pfxs); i < n; i++) {
130 const char *pfx = pfxs[i];
132 if (str_has_prefix(sec_name, pfx)) {
133 snprintf(buf, buf_sz, "%s", sec_name + 1);
134 sanitize_identifier(buf);
142 static void codegen_btf_dump_printf(void *ctx, const char *fmt, va_list args)
147 static int codegen_datasec_def(struct bpf_object *obj,
150 const struct btf_type *sec,
151 const char *obj_name)
153 const char *sec_name = btf__name_by_offset(btf, sec->name_off);
154 const struct btf_var_secinfo *sec_var = btf_var_secinfos(sec);
155 int i, err, off = 0, pad_cnt = 0, vlen = btf_vlen(sec);
156 char var_ident[256], sec_ident[256];
157 bool strip_mods = false;
159 if (!get_datasec_ident(sec_name, sec_ident, sizeof(sec_ident)))
162 if (strcmp(sec_name, ".kconfig") != 0)
165 printf(" struct %s__%s {\n", obj_name, sec_ident);
166 for (i = 0; i < vlen; i++, sec_var++) {
167 const struct btf_type *var = btf__type_by_id(btf, sec_var->type);
168 const char *var_name = btf__name_by_offset(btf, var->name_off);
169 DECLARE_LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts,
170 .field_name = var_ident,
172 .strip_mods = strip_mods,
174 int need_off = sec_var->offset, align_off, align;
175 __u32 var_type_id = var->type;
177 /* static variables are not exposed through BPF skeleton */
178 if (btf_var(var)->linkage == BTF_VAR_STATIC)
181 if (off > need_off) {
182 p_err("Something is wrong for %s's variable #%d: need offset %d, already at %d.\n",
183 sec_name, i, need_off, off);
187 align = btf__align_of(btf, var->type);
189 p_err("Failed to determine alignment of variable '%s': %d",
193 /* Assume 32-bit architectures when generating data section
194 * struct memory layout. Given bpftool can't know which target
195 * host architecture it's emitting skeleton for, we need to be
196 * conservative and assume 32-bit one to ensure enough padding
197 * bytes are generated for pointer and long types. This will
198 * still work correctly for 64-bit architectures, because in
199 * the worst case we'll generate unnecessary padding field,
200 * which on 64-bit architectures is not strictly necessary and
201 * would be handled by natural 8-byte alignment. But it still
202 * will be a correct memory layout, based on recorded offsets
208 align_off = (off + align - 1) / align * align;
209 if (align_off != need_off) {
210 printf("\t\tchar __pad%d[%d];\n",
211 pad_cnt, need_off - off);
215 /* sanitize variable name, e.g., for static vars inside
216 * a function, it's name is '<function name>.<variable name>',
217 * which we'll turn into a '<function name>_<variable name>'
220 strncat(var_ident, var_name, sizeof(var_ident) - 1);
221 sanitize_identifier(var_ident);
224 err = btf_dump__emit_type_decl(d, var_type_id, &opts);
229 off = sec_var->offset + sec_var->size;
231 printf(" } *%s;\n", sec_ident);
235 static const struct btf_type *find_type_for_map(struct btf *btf, const char *map_ident)
237 int n = btf__type_cnt(btf), i;
240 for (i = 1; i < n; i++) {
241 const struct btf_type *t = btf__type_by_id(btf, i);
244 if (!btf_is_datasec(t))
247 name = btf__str_by_offset(btf, t->name_off);
248 if (!get_datasec_ident(name, sec_ident, sizeof(sec_ident)))
251 if (strcmp(sec_ident, map_ident) == 0)
257 static bool is_mmapable_map(const struct bpf_map *map, char *buf, size_t sz)
261 if (bpf_map__type(map) == BPF_MAP_TYPE_ARENA && bpf_map__initial_value(map, &tmp_sz)) {
262 snprintf(buf, sz, "arena");
266 if (!bpf_map__is_internal(map) || !(bpf_map__map_flags(map) & BPF_F_MMAPABLE))
269 if (!get_map_ident(map, buf, sz))
275 static int codegen_datasecs(struct bpf_object *obj, const char *obj_name)
277 struct btf *btf = bpf_object__btf(obj);
280 const struct btf_type *sec;
284 d = btf_dump__new(btf, codegen_btf_dump_printf, NULL, NULL);
288 bpf_object__for_each_map(map, obj) {
289 /* only generate definitions for memory-mapped internal maps */
290 if (!is_mmapable_map(map, map_ident, sizeof(map_ident)))
293 sec = find_type_for_map(btf, map_ident);
295 /* In some cases (e.g., sections like .rodata.cst16 containing
296 * compiler allocated string constants only) there will be
297 * special internal maps with no corresponding DATASEC BTF
298 * type. In such case, generate empty structs for each such
299 * map. It will still be memory-mapped and its contents
300 * accessible from user-space through BPF skeleton.
303 printf(" struct %s__%s {\n", obj_name, map_ident);
304 printf(" } *%s;\n", map_ident);
306 err = codegen_datasec_def(obj, btf, d, sec, obj_name);
318 static bool btf_is_ptr_to_func_proto(const struct btf *btf,
319 const struct btf_type *v)
321 return btf_is_ptr(v) && btf_is_func_proto(btf__type_by_id(btf, v->type));
324 static int codegen_subskel_datasecs(struct bpf_object *obj, const char *obj_name)
326 struct btf *btf = bpf_object__btf(obj);
329 const struct btf_type *sec, *var;
330 const struct btf_var_secinfo *sec_var;
331 int i, err = 0, vlen;
332 char map_ident[256], sec_ident[256];
333 bool strip_mods = false, needs_typeof = false;
334 const char *sec_name, *var_name;
337 d = btf_dump__new(btf, codegen_btf_dump_printf, NULL, NULL);
341 bpf_object__for_each_map(map, obj) {
342 /* only generate definitions for memory-mapped internal maps */
343 if (!is_mmapable_map(map, map_ident, sizeof(map_ident)))
346 sec = find_type_for_map(btf, map_ident);
350 sec_name = btf__name_by_offset(btf, sec->name_off);
351 if (!get_datasec_ident(sec_name, sec_ident, sizeof(sec_ident)))
354 strip_mods = strcmp(sec_name, ".kconfig") != 0;
355 printf(" struct %s__%s {\n", obj_name, sec_ident);
357 sec_var = btf_var_secinfos(sec);
358 vlen = btf_vlen(sec);
359 for (i = 0; i < vlen; i++, sec_var++) {
360 DECLARE_LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts,
362 .strip_mods = strip_mods,
363 /* we'll print the name separately */
367 var = btf__type_by_id(btf, sec_var->type);
368 var_name = btf__name_by_offset(btf, var->name_off);
369 var_type_id = var->type;
371 /* static variables are not exposed through BPF skeleton */
372 if (btf_var(var)->linkage == BTF_VAR_STATIC)
375 /* The datasec member has KIND_VAR but we want the
376 * underlying type of the variable (e.g. KIND_INT).
378 var = skip_mods_and_typedefs(btf, var->type, NULL);
381 /* Func and array members require special handling.
382 * Instead of producing `typename *var`, they produce
383 * `typeof(typename) *var`. This allows us to keep a
384 * similar syntax where the identifier is just prefixed
385 * by *, allowing us to ignore C declaration minutiae.
387 needs_typeof = btf_is_array(var) || btf_is_ptr_to_func_proto(btf, var);
391 err = btf_dump__emit_type_decl(d, var_type_id, &opts);
398 printf(" *%s;\n", var_name);
400 printf(" } %s;\n", sec_ident);
408 static void codegen(const char *template, ...)
410 const char *src, *end;
411 int skip_tabs = 0, n;
416 n = strlen(template);
423 /* find out "baseline" indentation to skip */
424 while ((c = *src++)) {
427 } else if (c == '\n') {
430 p_err("unrecognized character at pos %td in template '%s': '%c'",
431 src - template - 1, template, c);
438 /* skip baseline indentation tabs */
439 for (n = skip_tabs; n > 0; n--, src++) {
441 p_err("not enough tabs at pos %td in template '%s'",
442 src - template - 1, template);
447 /* trim trailing whitespace */
448 end = strchrnul(src, '\n');
449 for (n = end - src; n > 0 && isspace(src[n - 1]); n--)
455 src = *end ? end + 1 : end;
459 /* print out using adjusted template */
460 va_start(args, template);
461 n = vprintf(s, args);
467 static void print_hex(const char *data, int data_sz)
471 for (i = 0, len = 0; i < data_sz; i++) {
472 int w = data[i] ? 4 : 2;
482 printf("\\x%02x", (unsigned char)data[i]);
486 static size_t bpf_map_mmap_sz(const struct bpf_map *map)
488 long page_sz = sysconf(_SC_PAGE_SIZE);
491 map_sz = (size_t)roundup(bpf_map__value_size(map), 8) * bpf_map__max_entries(map);
492 map_sz = roundup(map_sz, page_sz);
496 /* Emit type size asserts for all top-level fields in memory-mapped internal maps. */
497 static void codegen_asserts(struct bpf_object *obj, const char *obj_name)
499 struct btf *btf = bpf_object__btf(obj);
501 struct btf_var_secinfo *sec_var;
503 const struct btf_type *sec;
504 char map_ident[256], var_ident[256];
511 __attribute__((unused)) static void \n\
512 %1$s__assert(struct %1$s *s __attribute__((unused))) \n\
514 #ifdef __cplusplus \n\
515 #define _Static_assert static_assert \n\
519 bpf_object__for_each_map(map, obj) {
520 if (!is_mmapable_map(map, map_ident, sizeof(map_ident)))
523 sec = find_type_for_map(btf, map_ident);
525 /* best effort, couldn't find the type for this map */
529 sec_var = btf_var_secinfos(sec);
530 vlen = btf_vlen(sec);
532 for (i = 0; i < vlen; i++, sec_var++) {
533 const struct btf_type *var = btf__type_by_id(btf, sec_var->type);
534 const char *var_name = btf__name_by_offset(btf, var->name_off);
537 /* static variables are not exposed through BPF skeleton */
538 if (btf_var(var)->linkage == BTF_VAR_STATIC)
541 var_size = btf__resolve_size(btf, var->type);
546 strncat(var_ident, var_name, sizeof(var_ident) - 1);
547 sanitize_identifier(var_ident);
549 printf("\t_Static_assert(sizeof(s->%s->%s) == %ld, \"unexpected size of '%s'\");\n",
550 map_ident, var_ident, var_size, var_ident);
555 #ifdef __cplusplus \n\
556 #undef _Static_assert \n\
562 static void codegen_attach_detach(struct bpf_object *obj, const char *obj_name)
564 struct bpf_program *prog;
566 bpf_object__for_each_program(prog, obj) {
572 static inline int \n\
573 %1$s__%2$s__attach(struct %1$s *skel) \n\
575 int prog_fd = skel->progs.%2$s.prog_fd; \n\
576 ", obj_name, bpf_program__name(prog));
578 switch (bpf_program__type(prog)) {
579 case BPF_PROG_TYPE_RAW_TRACEPOINT:
580 tp_name = strchr(bpf_program__section_name(prog), '/') + 1;
581 printf("\tint fd = skel_raw_tracepoint_open(\"%s\", prog_fd);\n", tp_name);
583 case BPF_PROG_TYPE_TRACING:
584 case BPF_PROG_TYPE_LSM:
585 if (bpf_program__expected_attach_type(prog) == BPF_TRACE_ITER)
586 printf("\tint fd = skel_link_create(prog_fd, 0, BPF_TRACE_ITER);\n");
588 printf("\tint fd = skel_raw_tracepoint_open(NULL, prog_fd);\n");
591 printf("\tint fd = ((void)prog_fd, 0); /* auto-attach not supported */\n");
598 skel->links.%1$s_fd = fd; \n\
601 ", bpf_program__name(prog));
607 static inline int \n\
608 %1$s__attach(struct %1$s *skel) \n\
614 bpf_object__for_each_program(prog, obj) {
617 ret = ret < 0 ? ret : %1$s__%2$s__attach(skel); \n\
618 ", obj_name, bpf_program__name(prog));
623 return ret < 0 ? ret : 0; \n\
626 static inline void \n\
627 %1$s__detach(struct %1$s *skel) \n\
631 bpf_object__for_each_program(prog, obj) {
634 skel_closenz(skel->links.%1$s_fd); \n\
635 ", bpf_program__name(prog));
644 static void codegen_destroy(struct bpf_object *obj, const char *obj_name)
646 struct bpf_program *prog;
653 %1$s__destroy(struct %1$s *skel) \n\
657 %1$s__detach(skel); \n\
661 bpf_object__for_each_program(prog, obj) {
664 skel_closenz(skel->progs.%1$s.prog_fd); \n\
665 ", bpf_program__name(prog));
668 bpf_object__for_each_map(map, obj) {
669 if (!get_map_ident(map, ident, sizeof(ident)))
671 if (bpf_map__is_internal(map) &&
672 (bpf_map__map_flags(map) & BPF_F_MMAPABLE))
673 printf("\tskel_free_map_data(skel->%1$s, skel->maps.%1$s.initial_value, %2$zd);\n",
674 ident, bpf_map_mmap_sz(map));
677 skel_closenz(skel->maps.%1$s.map_fd); \n\
688 static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *header_guard)
690 DECLARE_LIBBPF_OPTS(gen_loader_opts, opts);
695 err = bpf_object__gen_loader(obj, &opts);
699 err = bpf_object__load(obj);
701 p_err("failed to load object file");
704 /* If there was no error during load then gen_loader_opts
705 * are populated with the loader program.
708 /* finish generating 'struct skel' */
715 codegen_attach_detach(obj, obj_name);
717 codegen_destroy(obj, obj_name);
721 static inline struct %1$s * \n\
724 struct %1$s *skel; \n\
726 skel = skel_alloc(sizeof(*skel)); \n\
729 skel->ctx.sz = (void *)&skel->links - (void *)skel; \n\
731 obj_name, opts.data_sz);
732 bpf_object__for_each_map(map, obj) {
733 const void *mmap_data = NULL;
734 size_t mmap_size = 0;
736 if (!is_mmapable_map(map, ident, sizeof(ident)))
742 static const char data[] __attribute__((__aligned__(8))) = \"\\\n\
744 mmap_data = bpf_map__initial_value(map, &mmap_size);
745 print_hex(mmap_data, mmap_size);
750 skel->%1$s = skel_prep_map_data((void *)data, %2$zd,\n\
751 sizeof(data) - 1);\n\
754 skel->maps.%1$s.initial_value = (__u64) (long) skel->%1$s;\n\
756 ", ident, bpf_map_mmap_sz(map));
762 %1$s__destroy(skel); \n\
766 static inline int \n\
767 %1$s__load(struct %1$s *skel) \n\
769 struct bpf_load_and_run_opts opts = {}; \n\
771 static const char opts_data[] __attribute__((__aligned__(8))) = \"\\\n\
774 print_hex(opts.data, opts.data_sz);
778 static const char opts_insn[] __attribute__((__aligned__(8))) = \"\\\n\
780 print_hex(opts.insns, opts.insns_sz);
785 opts.ctx = (struct bpf_loader_ctx *)skel; \n\
786 opts.data_sz = sizeof(opts_data) - 1; \n\
787 opts.data = (void *)opts_data; \n\
788 opts.insns_sz = sizeof(opts_insn) - 1; \n\
789 opts.insns = (void *)opts_insn; \n\
791 err = bpf_load_and_run(&opts); \n\
795 bpf_object__for_each_map(map, obj) {
796 const char *mmap_flags;
798 if (!is_mmapable_map(map, ident, sizeof(ident)))
801 if (bpf_map__map_flags(map) & BPF_F_RDONLY_PROG)
802 mmap_flags = "PROT_READ";
804 mmap_flags = "PROT_READ | PROT_WRITE";
808 skel->%1$s = skel_finalize_map_data(&skel->maps.%1$s.initial_value, \n\
809 %2$zd, %3$s, skel->maps.%1$s.map_fd);\n\
813 ident, bpf_map_mmap_sz(map), mmap_flags);
820 static inline struct %1$s * \n\
821 %1$s__open_and_load(void) \n\
823 struct %1$s *skel; \n\
825 skel = %1$s__open(); \n\
828 if (%1$s__load(skel)) { \n\
829 %1$s__destroy(skel); \n\
837 codegen_asserts(obj, obj_name);
851 codegen_maps_skeleton(struct bpf_object *obj, size_t map_cnt, bool mmaped)
864 s->map_cnt = %zu; \n\
865 s->map_skel_sz = sizeof(*s->maps); \n\
866 s->maps = (struct bpf_map_skeleton *)calloc(s->map_cnt, s->map_skel_sz);\n\
875 bpf_object__for_each_map(map, obj) {
876 if (!get_map_ident(map, ident, sizeof(ident)))
882 s->maps[%zu].name = \"%s\"; \n\
883 s->maps[%zu].map = &obj->maps.%s; \n\
885 i, bpf_map__name(map), i, ident);
886 /* memory-mapped internal maps */
887 if (mmaped && is_mmapable_map(map, ident, sizeof(ident))) {
888 printf("\ts->maps[%zu].mmaped = (void **)&obj->%s;\n",
896 codegen_progs_skeleton(struct bpf_object *obj, size_t prog_cnt, bool populate_links)
898 struct bpf_program *prog;
908 s->prog_cnt = %zu; \n\
909 s->prog_skel_sz = sizeof(*s->progs); \n\
910 s->progs = (struct bpf_prog_skeleton *)calloc(s->prog_cnt, s->prog_skel_sz);\n\
919 bpf_object__for_each_program(prog, obj) {
923 s->progs[%1$zu].name = \"%2$s\"; \n\
924 s->progs[%1$zu].prog = &obj->progs.%2$s;\n\
926 i, bpf_program__name(prog));
928 if (populate_links) {
931 s->progs[%1$zu].link = &obj->links.%2$s;\n\
933 i, bpf_program__name(prog));
939 static int walk_st_ops_shadow_vars(struct btf *btf, const char *ident,
940 const struct btf_type *map_type, __u32 map_type_id)
942 LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts, .indent_level = 3);
943 const struct btf_type *member_type;
944 __u32 offset, next_offset = 0;
945 const struct btf_member *m;
946 struct btf_dump *d = NULL;
947 const char *member_name;
948 __u32 member_type_id;
952 d = btf_dump__new(btf, codegen_btf_dump_printf, NULL, NULL);
956 n = btf_vlen(map_type);
957 for (i = 0, m = btf_members(map_type); i < n; i++, m++) {
958 member_type = skip_mods_and_typedefs(btf, m->type, &member_type_id);
959 member_name = btf__name_by_offset(btf, m->name_off);
961 offset = m->offset / 8;
962 if (next_offset < offset)
963 printf("\t\t\tchar __padding_%d[%d];\n", i, offset - next_offset);
965 switch (btf_kind(member_type)) {
969 case BTF_KIND_ENUM64:
972 opts.field_name = member_name;
973 err = btf_dump__emit_type_decl(d, member_type_id, &opts);
975 p_err("Failed to emit type declaration for %s: %d", member_name, err);
980 size = btf__resolve_size(btf, member_type_id);
982 p_err("Failed to resolve size of %s: %d\n", member_name, size);
987 next_offset = offset + size;
991 if (resolve_func_ptr(btf, m->type, NULL)) {
992 /* Function pointer */
993 printf("\t\t\tstruct bpf_program *%s;\n", member_name);
995 next_offset = offset + sizeof(void *);
998 /* All pointer types are unsupported except for
1004 /* Unsupported types
1006 * Types other than scalar types and function
1007 * pointers are currently not supported in order to
1008 * prevent conflicts in the generated code caused
1009 * by multiple definitions. For instance, if the
1010 * struct type FOO is used in a struct_ops map,
1011 * bpftool has to generate definitions for FOO,
1012 * which may result in conflicts if FOO is defined
1013 * in different skeleton files.
1015 size = btf__resolve_size(btf, member_type_id);
1017 p_err("Failed to resolve size of %s: %d\n", member_name, size);
1021 printf("\t\t\tchar __unsupported_%d[%d];\n", i, size);
1023 next_offset = offset + size;
1028 /* Cannot fail since it must be a struct type */
1029 size = btf__resolve_size(btf, map_type_id);
1030 if (next_offset < (__u32)size)
1031 printf("\t\t\tchar __padding_end[%d];\n", size - next_offset);
1039 /* Generate the pointer of the shadow type for a struct_ops map.
1041 * This function adds a pointer of the shadow type for a struct_ops map.
1042 * The members of a struct_ops map can be exported through a pointer to a
1043 * shadow type. The user can access these members through the pointer.
1045 * A shadow type includes not all members, only members of some types.
1046 * They are scalar types and function pointers. The function pointers are
1047 * translated to the pointer of the struct bpf_program. The scalar types
1048 * are translated to the original type without any modifiers.
1050 * Unsupported types will be translated to a char array to occupy the same
1051 * space as the original field, being renamed as __unsupported_*. The user
1052 * should treat these fields as opaque data.
1054 static int gen_st_ops_shadow_type(const char *obj_name, struct btf *btf, const char *ident,
1055 const struct bpf_map *map)
1057 const struct btf_type *map_type;
1058 const char *type_name;
1062 map_type_id = bpf_map__btf_value_type_id(map);
1063 if (map_type_id == 0)
1065 map_type = btf__type_by_id(btf, map_type_id);
1069 type_name = btf__name_by_offset(btf, map_type->name_off);
1071 printf("\t\tstruct %s__%s__%s {\n", obj_name, ident, type_name);
1073 err = walk_st_ops_shadow_vars(btf, ident, map_type, map_type_id);
1077 printf("\t\t} *%s;\n", ident);
1082 static int gen_st_ops_shadow(const char *obj_name, struct btf *btf, struct bpf_object *obj)
1084 int err, st_ops_cnt = 0;
1085 struct bpf_map *map;
1091 /* Generate the pointers to shadow types of
1094 bpf_object__for_each_map(map, obj) {
1095 if (bpf_map__type(map) != BPF_MAP_TYPE_STRUCT_OPS)
1097 if (!get_map_ident(map, ident, sizeof(ident)))
1100 if (st_ops_cnt == 0) /* first struct_ops map */
1101 printf("\tstruct {\n");
1104 err = gen_st_ops_shadow_type(obj_name, btf, ident, map);
1110 printf("\t} struct_ops;\n");
1115 /* Generate the code to initialize the pointers of shadow types. */
1116 static void gen_st_ops_shadow_init(struct btf *btf, struct bpf_object *obj)
1118 struct bpf_map *map;
1124 /* Initialize the pointers to_ops shadow types of
1127 bpf_object__for_each_map(map, obj) {
1128 if (bpf_map__type(map) != BPF_MAP_TYPE_STRUCT_OPS)
1130 if (!get_map_ident(map, ident, sizeof(ident)))
1134 obj->struct_ops.%1$s = bpf_map__initial_value(obj->maps.%1$s, NULL);\n\
1140 static int do_skeleton(int argc, char **argv)
1142 char header_guard[MAX_OBJ_NAME_LEN + sizeof("__SKEL_H__")];
1143 size_t map_cnt = 0, prog_cnt = 0, file_sz, mmap_sz;
1144 DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts);
1145 char obj_name[MAX_OBJ_NAME_LEN] = "", *obj_data;
1146 struct bpf_object *obj = NULL;
1149 struct bpf_program *prog;
1151 struct bpf_map *map;
1165 if (is_prefix(*argv, "name")) {
1168 if (obj_name[0] != '\0') {
1169 p_err("object name already specified");
1173 strncpy(obj_name, *argv, MAX_OBJ_NAME_LEN - 1);
1174 obj_name[MAX_OBJ_NAME_LEN - 1] = '\0';
1176 p_err("unknown arg %s", *argv);
1184 p_err("extra unknown arguments");
1188 if (stat(file, &st)) {
1189 p_err("failed to stat() %s: %s", file, strerror(errno));
1192 file_sz = st.st_size;
1193 mmap_sz = roundup(file_sz, sysconf(_SC_PAGE_SIZE));
1194 fd = open(file, O_RDONLY);
1196 p_err("failed to open() %s: %s", file, strerror(errno));
1199 obj_data = mmap(NULL, mmap_sz, PROT_READ, MAP_PRIVATE, fd, 0);
1200 if (obj_data == MAP_FAILED) {
1202 p_err("failed to mmap() %s: %s", file, strerror(errno));
1205 if (obj_name[0] == '\0')
1206 get_obj_name(obj_name, file);
1207 opts.object_name = obj_name;
1209 /* log_level1 + log_level2 + stats, but not stable UAPI */
1210 opts.kernel_log_level = 1 + 2 + 4;
1211 obj = bpf_object__open_mem(obj_data, file_sz, &opts);
1216 libbpf_strerror(err, err_buf, sizeof(err_buf));
1217 p_err("failed to open BPF object file: %s", err_buf);
1221 bpf_object__for_each_map(map, obj) {
1222 if (!get_map_ident(map, ident, sizeof(ident))) {
1223 p_err("ignoring unrecognized internal map '%s'...",
1224 bpf_map__name(map));
1229 bpf_object__for_each_program(prog, obj) {
1233 get_header_guard(header_guard, obj_name, "SKEL_H");
1237 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ \n\
1238 /* THIS FILE IS AUTOGENERATED BY BPFTOOL! */ \n\
1242 #include <bpf/skel_internal.h> \n\
1245 struct bpf_loader_ctx ctx; \n\
1247 obj_name, header_guard
1252 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ \n\
1254 /* THIS FILE IS AUTOGENERATED BY BPFTOOL! */ \n\
1258 #include <errno.h> \n\
1259 #include <stdlib.h> \n\
1260 #include <bpf/libbpf.h> \n\
1263 struct bpf_object_skeleton *skeleton; \n\
1264 struct bpf_object *obj; \n\
1266 obj_name, header_guard
1271 printf("\tstruct {\n");
1272 bpf_object__for_each_map(map, obj) {
1273 if (!get_map_ident(map, ident, sizeof(ident)))
1276 printf("\t\tstruct bpf_map_desc %s;\n", ident);
1278 printf("\t\tstruct bpf_map *%s;\n", ident);
1280 printf("\t} maps;\n");
1283 btf = bpf_object__btf(obj);
1284 err = gen_st_ops_shadow(obj_name, btf, obj);
1289 printf("\tstruct {\n");
1290 bpf_object__for_each_program(prog, obj) {
1292 printf("\t\tstruct bpf_prog_desc %s;\n",
1293 bpf_program__name(prog));
1295 printf("\t\tstruct bpf_program *%s;\n",
1296 bpf_program__name(prog));
1298 printf("\t} progs;\n");
1299 printf("\tstruct {\n");
1300 bpf_object__for_each_program(prog, obj) {
1302 printf("\t\tint %s_fd;\n",
1303 bpf_program__name(prog));
1305 printf("\t\tstruct bpf_link *%s;\n",
1306 bpf_program__name(prog));
1308 printf("\t} links;\n");
1312 err = codegen_datasecs(obj, obj_name);
1317 err = gen_trace(obj, obj_name, header_guard);
1324 #ifdef __cplusplus \n\
1325 static inline struct %1$s *open(const struct bpf_object_open_opts *opts = nullptr);\n\
1326 static inline struct %1$s *open_and_load(); \n\
1327 static inline int load(struct %1$s *skel); \n\
1328 static inline int attach(struct %1$s *skel); \n\
1329 static inline void detach(struct %1$s *skel); \n\
1330 static inline void destroy(struct %1$s *skel); \n\
1331 static inline const void *elf_bytes(size_t *sz); \n\
1332 #endif /* __cplusplus */ \n\
1336 %1$s__destroy(struct %1$s *obj) \n\
1340 if (obj->skeleton) \n\
1341 bpf_object__destroy_skeleton(obj->skeleton);\n\
1345 static inline int \n\
1346 %1$s__create_skeleton(struct %1$s *obj); \n\
1348 static inline struct %1$s * \n\
1349 %1$s__open_opts(const struct bpf_object_open_opts *opts) \n\
1351 struct %1$s *obj; \n\
1354 obj = (struct %1$s *)calloc(1, sizeof(*obj)); \n\
1360 err = %1$s__create_skeleton(obj); \n\
1364 err = bpf_object__open_skeleton(obj->skeleton, opts);\n\
1370 gen_st_ops_shadow_init(btf, obj);
1376 %1$s__destroy(obj); \n\
1381 static inline struct %1$s * \n\
1382 %1$s__open(void) \n\
1384 return %1$s__open_opts(NULL); \n\
1387 static inline int \n\
1388 %1$s__load(struct %1$s *obj) \n\
1390 return bpf_object__load_skeleton(obj->skeleton); \n\
1393 static inline struct %1$s * \n\
1394 %1$s__open_and_load(void) \n\
1396 struct %1$s *obj; \n\
1399 obj = %1$s__open(); \n\
1402 err = %1$s__load(obj); \n\
1404 %1$s__destroy(obj); \n\
1411 static inline int \n\
1412 %1$s__attach(struct %1$s *obj) \n\
1414 return bpf_object__attach_skeleton(obj->skeleton); \n\
1417 static inline void \n\
1418 %1$s__detach(struct %1$s *obj) \n\
1420 bpf_object__detach_skeleton(obj->skeleton); \n\
1429 static inline const void *%1$s__elf_bytes(size_t *sz); \n\
1431 static inline int \n\
1432 %1$s__create_skeleton(struct %1$s *obj) \n\
1434 struct bpf_object_skeleton *s; \n\
1437 s = (struct bpf_object_skeleton *)calloc(1, sizeof(*s));\n\
1443 s->sz = sizeof(*s); \n\
1444 s->name = \"%1$s\"; \n\
1445 s->obj = &obj->obj; \n\
1450 codegen_maps_skeleton(obj, map_cnt, true /*mmaped*/);
1451 codegen_progs_skeleton(obj, prog_cnt, true /*populate_links*/);
1456 s->data = %1$s__elf_bytes(&s->data_sz); \n\
1458 obj->skeleton = s; \n\
1461 bpf_object__destroy_skeleton(s); \n\
1465 static inline const void *%1$s__elf_bytes(size_t *sz) \n\
1467 static const char data[] __attribute__((__aligned__(8))) = \"\\\n\
1472 /* embed contents of BPF object file */
1473 print_hex(obj_data, file_sz);
1479 *sz = sizeof(data) - 1; \n\
1480 return (const void *)data; \n\
1483 #ifdef __cplusplus \n\
1484 struct %1$s *%1$s::open(const struct bpf_object_open_opts *opts) { return %1$s__open_opts(opts); }\n\
1485 struct %1$s *%1$s::open_and_load() { return %1$s__open_and_load(); } \n\
1486 int %1$s::load(struct %1$s *skel) { return %1$s__load(skel); } \n\
1487 int %1$s::attach(struct %1$s *skel) { return %1$s__attach(skel); } \n\
1488 void %1$s::detach(struct %1$s *skel) { %1$s__detach(skel); } \n\
1489 void %1$s::destroy(struct %1$s *skel) { %1$s__destroy(skel); } \n\
1490 const void *%1$s::elf_bytes(size_t *sz) { return %1$s__elf_bytes(sz); } \n\
1491 #endif /* __cplusplus */ \n\
1496 codegen_asserts(obj, obj_name);
1501 #endif /* %1$s */ \n\
1506 bpf_object__close(obj);
1508 munmap(obj_data, mmap_sz);
1513 /* Subskeletons are like skeletons, except they don't own the bpf_object,
1514 * associated maps, links, etc. Instead, they know about the existence of
1515 * variables, maps, programs and are able to find their locations
1516 * _at runtime_ from an already loaded bpf_object.
1518 * This allows for library-like BPF objects to have userspace counterparts
1519 * with access to their own items without having to know anything about the
1520 * final BPF object that the library was linked into.
1522 static int do_subskeleton(int argc, char **argv)
1524 char header_guard[MAX_OBJ_NAME_LEN + sizeof("__SUBSKEL_H__")];
1525 size_t i, len, file_sz, map_cnt = 0, prog_cnt = 0, mmap_sz, var_cnt = 0, var_idx = 0;
1526 DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts);
1527 char obj_name[MAX_OBJ_NAME_LEN] = "", *obj_data;
1528 struct bpf_object *obj = NULL;
1529 const char *file, *var_name;
1531 int fd, err = -1, map_type_id;
1532 const struct bpf_map *map;
1533 struct bpf_program *prog;
1535 const struct btf_type *map_type, *var_type;
1536 const struct btf_var_secinfo *var;
1549 if (is_prefix(*argv, "name")) {
1552 if (obj_name[0] != '\0') {
1553 p_err("object name already specified");
1557 strncpy(obj_name, *argv, MAX_OBJ_NAME_LEN - 1);
1558 obj_name[MAX_OBJ_NAME_LEN - 1] = '\0';
1560 p_err("unknown arg %s", *argv);
1568 p_err("extra unknown arguments");
1573 p_err("cannot use loader for subskeletons");
1577 if (stat(file, &st)) {
1578 p_err("failed to stat() %s: %s", file, strerror(errno));
1581 file_sz = st.st_size;
1582 mmap_sz = roundup(file_sz, sysconf(_SC_PAGE_SIZE));
1583 fd = open(file, O_RDONLY);
1585 p_err("failed to open() %s: %s", file, strerror(errno));
1588 obj_data = mmap(NULL, mmap_sz, PROT_READ, MAP_PRIVATE, fd, 0);
1589 if (obj_data == MAP_FAILED) {
1591 p_err("failed to mmap() %s: %s", file, strerror(errno));
1594 if (obj_name[0] == '\0')
1595 get_obj_name(obj_name, file);
1597 /* The empty object name allows us to use bpf_map__name and produce
1598 * ELF section names out of it. (".data" instead of "obj.data")
1600 opts.object_name = "";
1601 obj = bpf_object__open_mem(obj_data, file_sz, &opts);
1605 libbpf_strerror(errno, err_buf, sizeof(err_buf));
1606 p_err("failed to open BPF object file: %s", err_buf);
1611 btf = bpf_object__btf(obj);
1614 p_err("need btf type information for %s", obj_name);
1618 bpf_object__for_each_program(prog, obj) {
1622 /* First, count how many variables we have to find.
1623 * We need this in advance so the subskel can allocate the right
1624 * amount of storage.
1626 bpf_object__for_each_map(map, obj) {
1627 if (!get_map_ident(map, ident, sizeof(ident)))
1630 /* Also count all maps that have a name */
1633 if (!is_mmapable_map(map, ident, sizeof(ident)))
1636 map_type_id = bpf_map__btf_value_type_id(map);
1637 if (map_type_id <= 0) {
1641 map_type = btf__type_by_id(btf, map_type_id);
1643 var = btf_var_secinfos(map_type);
1644 len = btf_vlen(map_type);
1645 for (i = 0; i < len; i++, var++) {
1646 var_type = btf__type_by_id(btf, var->type);
1648 if (btf_var(var_type)->linkage == BTF_VAR_STATIC)
1655 get_header_guard(header_guard, obj_name, "SUBSKEL_H");
1658 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ \n\
1660 /* THIS FILE IS AUTOGENERATED! */ \n\
1664 #include <errno.h> \n\
1665 #include <stdlib.h> \n\
1666 #include <bpf/libbpf.h> \n\
1669 struct bpf_object *obj; \n\
1670 struct bpf_object_subskeleton *subskel; \n\
1671 ", obj_name, header_guard);
1674 printf("\tstruct {\n");
1675 bpf_object__for_each_map(map, obj) {
1676 if (!get_map_ident(map, ident, sizeof(ident)))
1678 printf("\t\tstruct bpf_map *%s;\n", ident);
1680 printf("\t} maps;\n");
1683 err = gen_st_ops_shadow(obj_name, btf, obj);
1688 printf("\tstruct {\n");
1689 bpf_object__for_each_program(prog, obj) {
1690 printf("\t\tstruct bpf_program *%s;\n",
1691 bpf_program__name(prog));
1693 printf("\t} progs;\n");
1696 err = codegen_subskel_datasecs(obj, obj_name);
1700 /* emit code that will allocate enough storage for all symbols */
1704 #ifdef __cplusplus \n\
1705 static inline struct %1$s *open(const struct bpf_object *src);\n\
1706 static inline void destroy(struct %1$s *skel); \n\
1707 #endif /* __cplusplus */ \n\
1710 static inline void \n\
1711 %1$s__destroy(struct %1$s *skel) \n\
1715 if (skel->subskel) \n\
1716 bpf_object__destroy_subskeleton(skel->subskel);\n\
1720 static inline struct %1$s * \n\
1721 %1$s__open(const struct bpf_object *src) \n\
1723 struct %1$s *obj; \n\
1724 struct bpf_object_subskeleton *s; \n\
1727 obj = (struct %1$s *)calloc(1, sizeof(*obj)); \n\
1732 s = (struct bpf_object_subskeleton *)calloc(1, sizeof(*s));\n\
1737 s->sz = sizeof(*s); \n\
1739 s->var_skel_sz = sizeof(*s->vars); \n\
1740 obj->subskel = s; \n\
1743 s->var_cnt = %2$d; \n\
1744 s->vars = (struct bpf_var_skeleton *)calloc(%2$d, sizeof(*s->vars));\n\
1753 /* walk through each symbol and emit the runtime representation */
1754 bpf_object__for_each_map(map, obj) {
1755 if (!is_mmapable_map(map, ident, sizeof(ident)))
1758 map_type_id = bpf_map__btf_value_type_id(map);
1759 if (map_type_id <= 0)
1760 /* skip over internal maps with no type*/
1763 map_type = btf__type_by_id(btf, map_type_id);
1764 var = btf_var_secinfos(map_type);
1765 len = btf_vlen(map_type);
1766 for (i = 0; i < len; i++, var++) {
1767 var_type = btf__type_by_id(btf, var->type);
1768 var_name = btf__name_by_offset(btf, var_type->name_off);
1770 if (btf_var(var_type)->linkage == BTF_VAR_STATIC)
1773 /* Note that we use the dot prefix in .data as the
1774 * field access operator i.e. maps%s becomes maps.data
1779 s->vars[%3$d].name = \"%1$s\"; \n\
1780 s->vars[%3$d].map = &obj->maps.%2$s; \n\
1781 s->vars[%3$d].addr = (void **) &obj->%2$s.%1$s;\n\
1782 ", var_name, ident, var_idx);
1788 codegen_maps_skeleton(obj, map_cnt, false /*mmaped*/);
1789 codegen_progs_skeleton(obj, prog_cnt, false /*links*/);
1794 err = bpf_object__open_subskeleton(s); \n\
1800 gen_st_ops_shadow_init(btf, obj);
1806 %1$s__destroy(obj); \n\
1811 #ifdef __cplusplus \n\
1812 struct %1$s *%1$s::open(const struct bpf_object *src) { return %1$s__open(src); }\n\
1813 void %1$s::destroy(struct %1$s *skel) { %1$s__destroy(skel); }\n\
1814 #endif /* __cplusplus */ \n\
1816 #endif /* %2$s */ \n\
1818 obj_name, header_guard);
1821 bpf_object__close(obj);
1823 munmap(obj_data, mmap_sz);
1828 static int do_object(int argc, char **argv)
1830 struct bpf_linker *linker;
1831 const char *output_file, *file;
1839 output_file = GET_ARG();
1841 linker = bpf_linker__new(output_file, NULL);
1843 p_err("failed to create BPF linker instance");
1850 err = bpf_linker__add_file(linker, file, NULL);
1852 p_err("failed to link '%s': %s (%d)", file, strerror(errno), errno);
1857 err = bpf_linker__finalize(linker);
1859 p_err("failed to finalize ELF file: %s (%d)", strerror(errno), errno);
1865 bpf_linker__free(linker);
1869 static int do_help(int argc, char **argv)
1872 jsonw_null(json_wtr);
1877 "Usage: %1$s %2$s object OUTPUT_FILE INPUT_FILE [INPUT_FILE...]\n"
1878 " %1$s %2$s skeleton FILE [name OBJECT_NAME]\n"
1879 " %1$s %2$s subskeleton FILE [name OBJECT_NAME]\n"
1880 " %1$s %2$s min_core_btf INPUT OUTPUT OBJECT [OBJECT...]\n"
1883 " " HELP_SPEC_OPTIONS " |\n"
1884 " {-L|--use-loader} }\n"
1891 static int btf_save_raw(const struct btf *btf, const char *path)
1898 data = btf__raw_data(btf, &data_sz);
1902 f = fopen(path, "wb");
1906 if (fwrite(data, 1, data_sz, f) != data_sz)
1913 struct btfgen_info {
1914 struct btf *src_btf;
1915 struct btf *marked_btf; /* btf structure used to mark used types */
1918 static size_t btfgen_hash_fn(long key, void *ctx)
1923 static bool btfgen_equal_fn(long k1, long k2, void *ctx)
1928 static void btfgen_free_info(struct btfgen_info *info)
1933 btf__free(info->src_btf);
1934 btf__free(info->marked_btf);
1939 static struct btfgen_info *
1940 btfgen_new_info(const char *targ_btf_path)
1942 struct btfgen_info *info;
1945 info = calloc(1, sizeof(*info));
1949 info->src_btf = btf__parse(targ_btf_path, NULL);
1950 if (!info->src_btf) {
1952 p_err("failed parsing '%s' BTF file: %s", targ_btf_path, strerror(errno));
1956 info->marked_btf = btf__parse(targ_btf_path, NULL);
1957 if (!info->marked_btf) {
1959 p_err("failed parsing '%s' BTF file: %s", targ_btf_path, strerror(errno));
1966 btfgen_free_info(info);
1971 #define MARKED UINT32_MAX
1973 static void btfgen_mark_member(struct btfgen_info *info, int type_id, int idx)
1975 const struct btf_type *t = btf__type_by_id(info->marked_btf, type_id);
1976 struct btf_member *m = btf_members(t) + idx;
1978 m->name_off = MARKED;
1982 btfgen_mark_type(struct btfgen_info *info, unsigned int type_id, bool follow_pointers)
1984 const struct btf_type *btf_type = btf__type_by_id(info->src_btf, type_id);
1985 struct btf_type *cloned_type;
1986 struct btf_param *param;
1987 struct btf_array *array;
1993 /* mark type on cloned BTF as used */
1994 cloned_type = (struct btf_type *) btf__type_by_id(info->marked_btf, type_id);
1995 cloned_type->name_off = MARKED;
1997 /* recursively mark other types needed by it */
1998 switch (btf_kind(btf_type)) {
2001 case BTF_KIND_FLOAT:
2003 case BTF_KIND_ENUM64:
2004 case BTF_KIND_STRUCT:
2005 case BTF_KIND_UNION:
2008 if (follow_pointers) {
2009 err = btfgen_mark_type(info, btf_type->type, follow_pointers);
2014 case BTF_KIND_CONST:
2015 case BTF_KIND_RESTRICT:
2016 case BTF_KIND_VOLATILE:
2017 case BTF_KIND_TYPEDEF:
2018 err = btfgen_mark_type(info, btf_type->type, follow_pointers);
2022 case BTF_KIND_ARRAY:
2023 array = btf_array(btf_type);
2025 /* mark array type */
2026 err = btfgen_mark_type(info, array->type, follow_pointers);
2027 /* mark array's index type */
2028 err = err ? : btfgen_mark_type(info, array->index_type, follow_pointers);
2032 case BTF_KIND_FUNC_PROTO:
2034 err = btfgen_mark_type(info, btf_type->type, follow_pointers);
2038 /* mark parameters types */
2039 param = btf_params(btf_type);
2040 for (i = 0; i < btf_vlen(btf_type); i++) {
2041 err = btfgen_mark_type(info, param->type, follow_pointers);
2047 /* tells if some other type needs to be handled */
2049 p_err("unsupported kind: %s (%d)", btf_kind_str(btf_type), type_id);
2056 static int btfgen_record_field_relo(struct btfgen_info *info, struct bpf_core_spec *targ_spec)
2058 struct btf *btf = info->src_btf;
2059 const struct btf_type *btf_type;
2060 struct btf_member *btf_member;
2061 struct btf_array *array;
2062 unsigned int type_id = targ_spec->root_type_id;
2065 /* mark root type */
2066 btf_type = btf__type_by_id(btf, type_id);
2067 err = btfgen_mark_type(info, type_id, false);
2071 /* mark types for complex types (arrays, unions, structures) */
2072 for (int i = 1; i < targ_spec->raw_len; i++) {
2073 /* skip typedefs and mods */
2074 while (btf_is_mod(btf_type) || btf_is_typedef(btf_type)) {
2075 type_id = btf_type->type;
2076 btf_type = btf__type_by_id(btf, type_id);
2079 switch (btf_kind(btf_type)) {
2080 case BTF_KIND_STRUCT:
2081 case BTF_KIND_UNION:
2082 idx = targ_spec->raw_spec[i];
2083 btf_member = btf_members(btf_type) + idx;
2086 btfgen_mark_member(info, type_id, idx);
2088 /* mark member's type */
2089 type_id = btf_member->type;
2090 btf_type = btf__type_by_id(btf, type_id);
2091 err = btfgen_mark_type(info, type_id, false);
2095 case BTF_KIND_ARRAY:
2096 array = btf_array(btf_type);
2097 type_id = array->type;
2098 btf_type = btf__type_by_id(btf, type_id);
2101 p_err("unsupported kind: %s (%d)",
2102 btf_kind_str(btf_type), btf_type->type);
2110 /* Mark types, members, and member types. Compared to btfgen_record_field_relo,
2111 * this function does not rely on the target spec for inferring members, but
2112 * uses the associated BTF.
2114 * The `behind_ptr` argument is used to stop marking of composite types reached
2115 * through a pointer. This way, we can keep BTF size in check while providing
2116 * reasonable match semantics.
2118 static int btfgen_mark_type_match(struct btfgen_info *info, __u32 type_id, bool behind_ptr)
2120 const struct btf_type *btf_type;
2121 struct btf *btf = info->src_btf;
2122 struct btf_type *cloned_type;
2128 btf_type = btf__type_by_id(btf, type_id);
2129 /* mark type on cloned BTF as used */
2130 cloned_type = (struct btf_type *)btf__type_by_id(info->marked_btf, type_id);
2131 cloned_type->name_off = MARKED;
2133 switch (btf_kind(btf_type)) {
2136 case BTF_KIND_FLOAT:
2138 case BTF_KIND_ENUM64:
2140 case BTF_KIND_STRUCT:
2141 case BTF_KIND_UNION: {
2142 struct btf_member *m = btf_members(btf_type);
2143 __u16 vlen = btf_vlen(btf_type);
2148 for (i = 0; i < vlen; i++, m++) {
2150 btfgen_mark_member(info, type_id, i);
2152 /* mark member's type */
2153 err = btfgen_mark_type_match(info, m->type, false);
2159 case BTF_KIND_CONST:
2161 case BTF_KIND_RESTRICT:
2162 case BTF_KIND_TYPEDEF:
2163 case BTF_KIND_VOLATILE:
2164 return btfgen_mark_type_match(info, btf_type->type, behind_ptr);
2166 return btfgen_mark_type_match(info, btf_type->type, true);
2167 case BTF_KIND_ARRAY: {
2168 struct btf_array *array;
2170 array = btf_array(btf_type);
2171 /* mark array type */
2172 err = btfgen_mark_type_match(info, array->type, false);
2173 /* mark array's index type */
2174 err = err ? : btfgen_mark_type_match(info, array->index_type, false);
2179 case BTF_KIND_FUNC_PROTO: {
2180 __u16 vlen = btf_vlen(btf_type);
2181 struct btf_param *param;
2184 err = btfgen_mark_type_match(info, btf_type->type, false);
2188 /* mark parameters types */
2189 param = btf_params(btf_type);
2190 for (i = 0; i < vlen; i++) {
2191 err = btfgen_mark_type_match(info, param->type, false);
2198 /* tells if some other type needs to be handled */
2200 p_err("unsupported kind: %s (%d)", btf_kind_str(btf_type), type_id);
2207 /* Mark types, members, and member types. Compared to btfgen_record_field_relo,
2208 * this function does not rely on the target spec for inferring members, but
2209 * uses the associated BTF.
2211 static int btfgen_record_type_match_relo(struct btfgen_info *info, struct bpf_core_spec *targ_spec)
2213 return btfgen_mark_type_match(info, targ_spec->root_type_id, false);
2216 static int btfgen_record_type_relo(struct btfgen_info *info, struct bpf_core_spec *targ_spec)
2218 return btfgen_mark_type(info, targ_spec->root_type_id, true);
2221 static int btfgen_record_enumval_relo(struct btfgen_info *info, struct bpf_core_spec *targ_spec)
2223 return btfgen_mark_type(info, targ_spec->root_type_id, false);
2226 static int btfgen_record_reloc(struct btfgen_info *info, struct bpf_core_spec *res)
2228 switch (res->relo_kind) {
2229 case BPF_CORE_FIELD_BYTE_OFFSET:
2230 case BPF_CORE_FIELD_BYTE_SIZE:
2231 case BPF_CORE_FIELD_EXISTS:
2232 case BPF_CORE_FIELD_SIGNED:
2233 case BPF_CORE_FIELD_LSHIFT_U64:
2234 case BPF_CORE_FIELD_RSHIFT_U64:
2235 return btfgen_record_field_relo(info, res);
2236 case BPF_CORE_TYPE_ID_LOCAL: /* BPF_CORE_TYPE_ID_LOCAL doesn't require kernel BTF */
2238 case BPF_CORE_TYPE_ID_TARGET:
2239 case BPF_CORE_TYPE_EXISTS:
2240 case BPF_CORE_TYPE_SIZE:
2241 return btfgen_record_type_relo(info, res);
2242 case BPF_CORE_TYPE_MATCHES:
2243 return btfgen_record_type_match_relo(info, res);
2244 case BPF_CORE_ENUMVAL_EXISTS:
2245 case BPF_CORE_ENUMVAL_VALUE:
2246 return btfgen_record_enumval_relo(info, res);
2252 static struct bpf_core_cand_list *
2253 btfgen_find_cands(const struct btf *local_btf, const struct btf *targ_btf, __u32 local_id)
2255 const struct btf_type *local_type;
2256 struct bpf_core_cand_list *cands = NULL;
2257 struct bpf_core_cand local_cand = {};
2258 size_t local_essent_len;
2259 const char *local_name;
2262 local_cand.btf = local_btf;
2263 local_cand.id = local_id;
2265 local_type = btf__type_by_id(local_btf, local_id);
2271 local_name = btf__name_by_offset(local_btf, local_type->name_off);
2276 local_essent_len = bpf_core_essential_name_len(local_name);
2278 cands = calloc(1, sizeof(*cands));
2282 err = bpf_core_add_cands(&local_cand, local_essent_len, targ_btf, "vmlinux", 1, cands);
2289 bpf_core_free_cands(cands);
2294 /* Record relocation information for a single BPF object */
2295 static int btfgen_record_obj(struct btfgen_info *info, const char *obj_path)
2297 const struct btf_ext_info_sec *sec;
2298 const struct bpf_core_relo *relo;
2299 const struct btf_ext_info *seg;
2300 struct hashmap_entry *entry;
2301 struct hashmap *cand_cache = NULL;
2302 struct btf_ext *btf_ext = NULL;
2303 unsigned int relo_idx;
2304 struct btf *btf = NULL;
2308 btf = btf__parse(obj_path, &btf_ext);
2311 p_err("failed to parse BPF object '%s': %s", obj_path, strerror(errno));
2316 p_err("failed to parse BPF object '%s': section %s not found",
2317 obj_path, BTF_EXT_ELF_SEC);
2322 if (btf_ext->core_relo_info.len == 0) {
2327 cand_cache = hashmap__new(btfgen_hash_fn, btfgen_equal_fn, NULL);
2328 if (IS_ERR(cand_cache)) {
2329 err = PTR_ERR(cand_cache);
2333 seg = &btf_ext->core_relo_info;
2334 for_each_btf_ext_sec(seg, sec) {
2335 for_each_btf_ext_rec(seg, sec, relo_idx, relo) {
2336 struct bpf_core_spec specs_scratch[3] = {};
2337 struct bpf_core_relo_res targ_res = {};
2338 struct bpf_core_cand_list *cands = NULL;
2339 const char *sec_name = btf__name_by_offset(btf, sec->sec_name_off);
2341 if (relo->kind != BPF_CORE_TYPE_ID_LOCAL &&
2342 !hashmap__find(cand_cache, relo->type_id, &cands)) {
2343 cands = btfgen_find_cands(btf, info->src_btf, relo->type_id);
2349 err = hashmap__set(cand_cache, relo->type_id, cands,
2355 err = bpf_core_calc_relo_insn(sec_name, relo, relo_idx, btf, cands,
2356 specs_scratch, &targ_res);
2360 /* specs_scratch[2] is the target spec */
2361 err = btfgen_record_reloc(info, &specs_scratch[2]);
2369 btf_ext__free(btf_ext);
2371 if (!IS_ERR_OR_NULL(cand_cache)) {
2372 hashmap__for_each_entry(cand_cache, entry, i) {
2373 bpf_core_free_cands(entry->pvalue);
2375 hashmap__free(cand_cache);
2381 static int btfgen_remap_id(__u32 *type_id, void *ctx)
2383 unsigned int *ids = ctx;
2385 *type_id = ids[*type_id];
2390 /* Generate BTF from relocation information previously recorded */
2391 static struct btf *btfgen_get_btf(struct btfgen_info *info)
2393 struct btf *btf_new = NULL;
2394 unsigned int *ids = NULL;
2395 unsigned int i, n = btf__type_cnt(info->marked_btf);
2398 btf_new = btf__new_empty();
2404 ids = calloc(n, sizeof(*ids));
2410 /* first pass: add all marked types to btf_new and add their new ids to the ids map */
2411 for (i = 1; i < n; i++) {
2412 const struct btf_type *cloned_type, *type;
2416 cloned_type = btf__type_by_id(info->marked_btf, i);
2418 if (cloned_type->name_off != MARKED)
2421 type = btf__type_by_id(info->src_btf, i);
2423 /* add members for struct and union */
2424 if (btf_is_composite(type)) {
2425 struct btf_member *cloned_m, *m;
2426 unsigned short vlen;
2429 name = btf__str_by_offset(info->src_btf, type->name_off);
2431 if (btf_is_struct(type))
2432 err = btf__add_struct(btf_new, name, type->size);
2434 err = btf__add_union(btf_new, name, type->size);
2440 cloned_m = btf_members(cloned_type);
2441 m = btf_members(type);
2442 vlen = btf_vlen(cloned_type);
2443 for (idx_src = 0; idx_src < vlen; idx_src++, cloned_m++, m++) {
2444 /* add only members that are marked as used */
2445 if (cloned_m->name_off != MARKED)
2448 name = btf__str_by_offset(info->src_btf, m->name_off);
2449 err = btf__add_field(btf_new, name, m->type,
2450 btf_member_bit_offset(cloned_type, idx_src),
2451 btf_member_bitfield_size(cloned_type, idx_src));
2456 err = btf__add_type(btf_new, info->src_btf, type);
2462 /* add ID mapping */
2466 /* second pass: fix up type ids */
2467 for (i = 1; i < btf__type_cnt(btf_new); i++) {
2468 struct btf_type *btf_type = (struct btf_type *) btf__type_by_id(btf_new, i);
2470 err = btf_type_visit_type_ids(btf_type, btfgen_remap_id, ids);
2485 /* Create minimized BTF file for a set of BPF objects.
2487 * The BTFGen algorithm is divided in two main parts: (1) collect the
2488 * BTF types that are involved in relocations and (2) generate the BTF
2489 * object using the collected types.
2491 * In order to collect the types involved in the relocations, we parse
2492 * the BTF and BTF.ext sections of the BPF objects and use
2493 * bpf_core_calc_relo_insn() to get the target specification, this
2494 * indicates how the types and fields are used in a relocation.
2496 * Types are recorded in different ways according to the kind of the
2497 * relocation. For field-based relocations only the members that are
2498 * actually used are saved in order to reduce the size of the generated
2499 * BTF file. For type-based relocations empty struct / unions are
2500 * generated and for enum-based relocations the whole type is saved.
2502 * The second part of the algorithm generates the BTF object. It creates
2503 * an empty BTF object and fills it with the types recorded in the
2504 * previous step. This function takes care of only adding the structure
2505 * and union members that were marked as used and it also fixes up the
2506 * type IDs on the generated BTF object.
2508 static int minimize_btf(const char *src_btf, const char *dst_btf, const char *objspaths[])
2510 struct btfgen_info *info;
2511 struct btf *btf_new = NULL;
2514 info = btfgen_new_info(src_btf);
2517 p_err("failed to allocate info structure: %s", strerror(errno));
2521 for (i = 0; objspaths[i] != NULL; i++) {
2522 err = btfgen_record_obj(info, objspaths[i]);
2524 p_err("error recording relocations for %s: %s", objspaths[i],
2530 btf_new = btfgen_get_btf(info);
2533 p_err("error generating BTF: %s", strerror(errno));
2537 err = btf_save_raw(btf_new, dst_btf);
2539 p_err("error saving btf file: %s", strerror(errno));
2545 btfgen_free_info(info);
2550 static int do_min_core_btf(int argc, char **argv)
2552 const char *input, *output, **objs;
2563 objs = (const char **) calloc(argc + 1, sizeof(*objs));
2565 p_err("failed to allocate array for object names");
2571 objs[i++] = GET_ARG();
2573 err = minimize_btf(input, output, objs);
2578 static const struct cmd cmds[] = {
2579 { "object", do_object },
2580 { "skeleton", do_skeleton },
2581 { "subskeleton", do_subskeleton },
2582 { "min_core_btf", do_min_core_btf},
2583 { "help", do_help },
2587 int do_gen(int argc, char **argv)
2589 return cmd_select(cmds, argc, argv, do_help);