1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 /* Copyright (C) 2019 Facebook */
10 #include <linux/err.h>
16 #include <bpf/libbpf.h>
17 #include <sys/types.h>
21 #include <bpf/bpf_gen_internal.h>
23 #include "json_writer.h"
26 #define MAX_OBJ_NAME_LEN 64
28 static void sanitize_identifier(char *name)
32 for (i = 0; name[i]; i++)
33 if (!isalnum(name[i]) && name[i] != '_')
37 static bool str_has_suffix(const char *str, const char *suffix)
39 size_t i, n1 = strlen(str), n2 = strlen(suffix);
44 for (i = 0; i < n2; i++) {
45 if (str[n1 - i - 1] != suffix[n2 - i - 1])
52 static void get_obj_name(char *name, const char *file)
54 /* Using basename() GNU version which doesn't modify arg. */
55 strncpy(name, basename(file), MAX_OBJ_NAME_LEN - 1);
56 name[MAX_OBJ_NAME_LEN - 1] = '\0';
57 if (str_has_suffix(name, ".o"))
58 name[strlen(name) - 2] = '\0';
59 sanitize_identifier(name);
62 static void get_header_guard(char *guard, const char *obj_name)
66 sprintf(guard, "__%s_SKEL_H__", obj_name);
67 for (i = 0; guard[i]; i++)
68 guard[i] = toupper(guard[i]);
71 static const char *get_map_ident(const struct bpf_map *map)
73 const char *name = bpf_map__name(map);
75 if (!bpf_map__is_internal(map))
78 if (str_has_suffix(name, ".data"))
80 else if (str_has_suffix(name, ".rodata"))
82 else if (str_has_suffix(name, ".bss"))
84 else if (str_has_suffix(name, ".kconfig"))
90 static void codegen_btf_dump_printf(void *ctx, const char *fmt, va_list args)
95 static int codegen_datasec_def(struct bpf_object *obj,
98 const struct btf_type *sec,
101 const char *sec_name = btf__name_by_offset(btf, sec->name_off);
102 const struct btf_var_secinfo *sec_var = btf_var_secinfos(sec);
103 int i, err, off = 0, pad_cnt = 0, vlen = btf_vlen(sec);
104 const char *sec_ident;
106 bool strip_mods = false;
108 if (strcmp(sec_name, ".data") == 0) {
111 } else if (strcmp(sec_name, ".bss") == 0) {
114 } else if (strcmp(sec_name, ".rodata") == 0) {
115 sec_ident = "rodata";
117 } else if (strcmp(sec_name, ".kconfig") == 0) {
118 sec_ident = "kconfig";
123 printf(" struct %s__%s {\n", obj_name, sec_ident);
124 for (i = 0; i < vlen; i++, sec_var++) {
125 const struct btf_type *var = btf__type_by_id(btf, sec_var->type);
126 const char *var_name = btf__name_by_offset(btf, var->name_off);
127 DECLARE_LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts,
128 .field_name = var_ident,
130 .strip_mods = strip_mods,
132 int need_off = sec_var->offset, align_off, align;
133 __u32 var_type_id = var->type;
135 /* static variables are not exposed through BPF skeleton */
136 if (btf_var(var)->linkage == BTF_VAR_STATIC)
139 if (off > need_off) {
140 p_err("Something is wrong for %s's variable #%d: need offset %d, already at %d.\n",
141 sec_name, i, need_off, off);
145 align = btf__align_of(btf, var->type);
147 p_err("Failed to determine alignment of variable '%s': %d",
151 /* Assume 32-bit architectures when generating data section
152 * struct memory layout. Given bpftool can't know which target
153 * host architecture it's emitting skeleton for, we need to be
154 * conservative and assume 32-bit one to ensure enough padding
155 * bytes are generated for pointer and long types. This will
156 * still work correctly for 64-bit architectures, because in
157 * the worst case we'll generate unnecessary padding field,
158 * which on 64-bit architectures is not strictly necessary and
159 * would be handled by natural 8-byte alignment. But it still
160 * will be a correct memory layout, based on recorded offsets
166 align_off = (off + align - 1) / align * align;
167 if (align_off != need_off) {
168 printf("\t\tchar __pad%d[%d];\n",
169 pad_cnt, need_off - off);
173 /* sanitize variable name, e.g., for static vars inside
174 * a function, it's name is '<function name>.<variable name>',
175 * which we'll turn into a '<function name>_<variable name>'
178 strncat(var_ident, var_name, sizeof(var_ident) - 1);
179 sanitize_identifier(var_ident);
182 err = btf_dump__emit_type_decl(d, var_type_id, &opts);
187 off = sec_var->offset + sec_var->size;
189 printf(" } *%s;\n", sec_ident);
193 static int codegen_datasecs(struct bpf_object *obj, const char *obj_name)
195 struct btf *btf = bpf_object__btf(obj);
196 int n = btf__get_nr_types(btf);
200 d = btf_dump__new(btf, NULL, NULL, codegen_btf_dump_printf);
204 for (i = 1; i <= n; i++) {
205 const struct btf_type *t = btf__type_by_id(btf, i);
207 if (!btf_is_datasec(t))
210 err = codegen_datasec_def(obj, btf, d, t, obj_name);
219 static void codegen(const char *template, ...)
221 const char *src, *end;
222 int skip_tabs = 0, n;
227 n = strlen(template);
234 /* find out "baseline" indentation to skip */
235 while ((c = *src++)) {
238 } else if (c == '\n') {
241 p_err("unrecognized character at pos %td in template '%s'",
242 src - template - 1, template);
249 /* skip baseline indentation tabs */
250 for (n = skip_tabs; n > 0; n--, src++) {
252 p_err("not enough tabs at pos %td in template '%s'",
253 src - template - 1, template);
258 /* trim trailing whitespace */
259 end = strchrnul(src, '\n');
260 for (n = end - src; n > 0 && isspace(src[n - 1]); n--)
266 src = *end ? end + 1 : end;
270 /* print out using adjusted template */
271 va_start(args, template);
272 n = vprintf(s, args);
278 static void print_hex(const char *data, int data_sz)
282 for (i = 0, len = 0; i < data_sz; i++) {
283 int w = data[i] ? 4 : 2;
293 printf("\\x%02x", (unsigned char)data[i]);
297 static size_t bpf_map_mmap_sz(const struct bpf_map *map)
299 long page_sz = sysconf(_SC_PAGE_SIZE);
302 map_sz = (size_t)roundup(bpf_map__value_size(map), 8) * bpf_map__max_entries(map);
303 map_sz = roundup(map_sz, page_sz);
307 static void codegen_attach_detach(struct bpf_object *obj, const char *obj_name)
309 struct bpf_program *prog;
311 bpf_object__for_each_program(prog, obj) {
317 static inline int \n\
318 %1$s__%2$s__attach(struct %1$s *skel) \n\
320 int prog_fd = skel->progs.%2$s.prog_fd; \n\
321 ", obj_name, bpf_program__name(prog));
323 switch (bpf_program__get_type(prog)) {
324 case BPF_PROG_TYPE_RAW_TRACEPOINT:
325 tp_name = strchr(bpf_program__section_name(prog), '/') + 1;
326 printf("\tint fd = bpf_raw_tracepoint_open(\"%s\", prog_fd);\n", tp_name);
328 case BPF_PROG_TYPE_TRACING:
329 printf("\tint fd = bpf_raw_tracepoint_open(NULL, prog_fd);\n");
332 printf("\tint fd = ((void)prog_fd, 0); /* auto-attach not supported */\n");
339 skel->links.%1$s_fd = fd; \n\
342 ", bpf_program__name(prog));
348 static inline int \n\
349 %1$s__attach(struct %1$s *skel) \n\
355 bpf_object__for_each_program(prog, obj) {
358 ret = ret < 0 ? ret : %1$s__%2$s__attach(skel); \n\
359 ", obj_name, bpf_program__name(prog));
364 return ret < 0 ? ret : 0; \n\
367 static inline void \n\
368 %1$s__detach(struct %1$s *skel) \n\
372 bpf_object__for_each_program(prog, obj) {
375 skel_closenz(skel->links.%1$s_fd); \n\
376 ", bpf_program__name(prog));
385 static void codegen_destroy(struct bpf_object *obj, const char *obj_name)
387 struct bpf_program *prog;
393 %1$s__destroy(struct %1$s *skel) \n\
397 %1$s__detach(skel); \n\
401 bpf_object__for_each_program(prog, obj) {
404 skel_closenz(skel->progs.%1$s.prog_fd); \n\
405 ", bpf_program__name(prog));
408 bpf_object__for_each_map(map, obj) {
411 ident = get_map_ident(map);
414 if (bpf_map__is_internal(map) &&
415 (bpf_map__def(map)->map_flags & BPF_F_MMAPABLE))
416 printf("\tmunmap(skel->%1$s, %2$zd);\n",
417 ident, bpf_map_mmap_sz(map));
420 skel_closenz(skel->maps.%1$s.map_fd); \n\
431 static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *header_guard)
433 struct bpf_object_load_attr load_attr = {};
434 DECLARE_LIBBPF_OPTS(gen_loader_opts, opts);
438 err = bpf_object__gen_loader(obj, &opts);
444 /* log_level1 + log_level2 + stats, but not stable UAPI */
445 load_attr.log_level = 1 + 2 + 4;
447 err = bpf_object__load_xattr(&load_attr);
449 p_err("failed to load object file");
452 /* If there was no error during load then gen_loader_opts
453 * are populated with the loader program.
456 /* finish generating 'struct skel' */
463 codegen_attach_detach(obj, obj_name);
465 codegen_destroy(obj, obj_name);
469 static inline struct %1$s * \n\
472 struct %1$s *skel; \n\
474 skel = calloc(sizeof(*skel), 1); \n\
477 skel->ctx.sz = (void *)&skel->links - (void *)skel; \n\
479 obj_name, opts.data_sz);
480 bpf_object__for_each_map(map, obj) {
482 const void *mmap_data = NULL;
483 size_t mmap_size = 0;
485 ident = get_map_ident(map);
489 if (!bpf_map__is_internal(map) ||
490 !(bpf_map__def(map)->map_flags & BPF_F_MMAPABLE))
496 mmap(NULL, %2$zd, PROT_READ | PROT_WRITE,\n\
497 MAP_SHARED | MAP_ANONYMOUS, -1, 0); \n\
498 if (skel->%1$s == (void *) -1) \n\
500 memcpy(skel->%1$s, (void *)\"\\ \n\
501 ", ident, bpf_map_mmap_sz(map));
502 mmap_data = bpf_map__initial_value(map, &mmap_size);
503 print_hex(mmap_data, mmap_size);
504 printf("\", %2$zd);\n"
505 "\tskel->maps.%1$s.initial_value = (__u64)(long)skel->%1$s;\n",
512 %1$s__destroy(skel); \n\
516 static inline int \n\
517 %1$s__load(struct %1$s *skel) \n\
519 struct bpf_load_and_run_opts opts = {}; \n\
522 opts.ctx = (struct bpf_loader_ctx *)skel; \n\
523 opts.data_sz = %2$d; \n\
524 opts.data = (void *)\"\\ \n\
526 obj_name, opts.data_sz);
527 print_hex(opts.data, opts.data_sz);
535 opts.insns_sz = %d; \n\
536 opts.insns = (void *)\"\\ \n\
539 print_hex(opts.insns, opts.insns_sz);
543 err = bpf_load_and_run(&opts); \n\
547 bpf_object__for_each_map(map, obj) {
548 const char *ident, *mmap_flags;
550 ident = get_map_ident(map);
554 if (!bpf_map__is_internal(map) ||
555 !(bpf_map__def(map)->map_flags & BPF_F_MMAPABLE))
557 if (bpf_map__def(map)->map_flags & BPF_F_RDONLY_PROG)
558 mmap_flags = "PROT_READ";
560 mmap_flags = "PROT_READ | PROT_WRITE";
562 printf("\tskel->%1$s =\n"
563 "\t\tmmap(skel->%1$s, %2$zd, %3$s, MAP_SHARED | MAP_FIXED,\n"
564 "\t\t\tskel->maps.%1$s.map_fd, 0);\n",
565 ident, bpf_map_mmap_sz(map), mmap_flags);
572 static inline struct %1$s * \n\
573 %1$s__open_and_load(void) \n\
575 struct %1$s *skel; \n\
577 skel = %1$s__open(); \n\
580 if (%1$s__load(skel)) { \n\
581 %1$s__destroy(skel); \n\
599 static int do_skeleton(int argc, char **argv)
601 char header_guard[MAX_OBJ_NAME_LEN + sizeof("__SKEL_H__")];
602 size_t i, map_cnt = 0, prog_cnt = 0, file_sz, mmap_sz;
603 DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts);
604 char obj_name[MAX_OBJ_NAME_LEN] = "", *obj_data;
605 struct bpf_object *obj = NULL;
606 const char *file, *ident;
607 struct bpf_program *prog;
623 if (is_prefix(*argv, "name")) {
626 if (obj_name[0] != '\0') {
627 p_err("object name already specified");
631 strncpy(obj_name, *argv, MAX_OBJ_NAME_LEN - 1);
632 obj_name[MAX_OBJ_NAME_LEN - 1] = '\0';
634 p_err("unknown arg %s", *argv);
642 p_err("extra unknown arguments");
646 if (stat(file, &st)) {
647 p_err("failed to stat() %s: %s", file, strerror(errno));
650 file_sz = st.st_size;
651 mmap_sz = roundup(file_sz, sysconf(_SC_PAGE_SIZE));
652 fd = open(file, O_RDONLY);
654 p_err("failed to open() %s: %s", file, strerror(errno));
657 obj_data = mmap(NULL, mmap_sz, PROT_READ, MAP_PRIVATE, fd, 0);
658 if (obj_data == MAP_FAILED) {
660 p_err("failed to mmap() %s: %s", file, strerror(errno));
663 if (obj_name[0] == '\0')
664 get_obj_name(obj_name, file);
665 opts.object_name = obj_name;
666 obj = bpf_object__open_mem(obj_data, file_sz, &opts);
670 libbpf_strerror(PTR_ERR(obj), err_buf, sizeof(err_buf));
671 p_err("failed to open BPF object file: %s", err_buf);
676 bpf_object__for_each_map(map, obj) {
677 ident = get_map_ident(map);
679 p_err("ignoring unrecognized internal map '%s'...",
685 bpf_object__for_each_program(prog, obj) {
689 get_header_guard(header_guard, obj_name);
693 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ \n\
694 /* THIS FILE IS AUTOGENERATED! */ \n\
698 #include <stdlib.h> \n\
699 #include <bpf/bpf.h> \n\
700 #include <bpf/skel_internal.h> \n\
703 struct bpf_loader_ctx ctx; \n\
705 obj_name, header_guard
710 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ \n\
712 /* THIS FILE IS AUTOGENERATED! */ \n\
716 #include <errno.h> \n\
717 #include <stdlib.h> \n\
718 #include <bpf/libbpf.h> \n\
721 struct bpf_object_skeleton *skeleton; \n\
722 struct bpf_object *obj; \n\
724 obj_name, header_guard
729 printf("\tstruct {\n");
730 bpf_object__for_each_map(map, obj) {
731 ident = get_map_ident(map);
735 printf("\t\tstruct bpf_map_desc %s;\n", ident);
737 printf("\t\tstruct bpf_map *%s;\n", ident);
739 printf("\t} maps;\n");
743 printf("\tstruct {\n");
744 bpf_object__for_each_program(prog, obj) {
746 printf("\t\tstruct bpf_prog_desc %s;\n",
747 bpf_program__name(prog));
749 printf("\t\tstruct bpf_program *%s;\n",
750 bpf_program__name(prog));
752 printf("\t} progs;\n");
753 printf("\tstruct {\n");
754 bpf_object__for_each_program(prog, obj) {
756 printf("\t\tint %s_fd;\n",
757 bpf_program__name(prog));
759 printf("\t\tstruct bpf_link *%s;\n",
760 bpf_program__name(prog));
762 printf("\t} links;\n");
765 btf = bpf_object__btf(obj);
767 err = codegen_datasecs(obj, obj_name);
772 err = gen_trace(obj, obj_name, header_guard);
781 %1$s__destroy(struct %1$s *obj) \n\
785 if (obj->skeleton) \n\
786 bpf_object__destroy_skeleton(obj->skeleton);\n\
790 static inline int \n\
791 %1$s__create_skeleton(struct %1$s *obj); \n\
793 static inline struct %1$s * \n\
794 %1$s__open_opts(const struct bpf_object_open_opts *opts) \n\
796 struct %1$s *obj; \n\
799 obj = (struct %1$s *)calloc(1, sizeof(*obj)); \n\
805 err = %1$s__create_skeleton(obj); \n\
806 err = err ?: bpf_object__open_skeleton(obj->skeleton, opts);\n\
812 %1$s__destroy(obj); \n\
817 static inline struct %1$s * \n\
820 return %1$s__open_opts(NULL); \n\
823 static inline int \n\
824 %1$s__load(struct %1$s *obj) \n\
826 return bpf_object__load_skeleton(obj->skeleton); \n\
829 static inline struct %1$s * \n\
830 %1$s__open_and_load(void) \n\
832 struct %1$s *obj; \n\
835 obj = %1$s__open(); \n\
838 err = %1$s__load(obj); \n\
840 %1$s__destroy(obj); \n\
847 static inline int \n\
848 %1$s__attach(struct %1$s *obj) \n\
850 return bpf_object__attach_skeleton(obj->skeleton); \n\
853 static inline void \n\
854 %1$s__detach(struct %1$s *obj) \n\
856 return bpf_object__detach_skeleton(obj->skeleton); \n\
865 static inline int \n\
866 %1$s__create_skeleton(struct %1$s *obj) \n\
868 struct bpf_object_skeleton *s; \n\
870 s = (struct bpf_object_skeleton *)calloc(1, sizeof(*s));\n\
873 obj->skeleton = s; \n\
875 s->sz = sizeof(*s); \n\
876 s->name = \"%1$s\"; \n\
877 s->obj = &obj->obj; \n\
886 s->map_cnt = %zu; \n\
887 s->map_skel_sz = sizeof(*s->maps); \n\
888 s->maps = (struct bpf_map_skeleton *)calloc(s->map_cnt, s->map_skel_sz);\n\
895 bpf_object__for_each_map(map, obj) {
896 ident = get_map_ident(map);
904 s->maps[%zu].name = \"%s\"; \n\
905 s->maps[%zu].map = &obj->maps.%s; \n\
907 i, bpf_map__name(map), i, ident);
908 /* memory-mapped internal maps */
909 if (bpf_map__is_internal(map) &&
910 (bpf_map__def(map)->map_flags & BPF_F_MMAPABLE)) {
911 printf("\ts->maps[%zu].mmaped = (void **)&obj->%s;\n",
922 s->prog_cnt = %zu; \n\
923 s->prog_skel_sz = sizeof(*s->progs); \n\
924 s->progs = (struct bpf_prog_skeleton *)calloc(s->prog_cnt, s->prog_skel_sz);\n\
931 bpf_object__for_each_program(prog, obj) {
935 s->progs[%1$zu].name = \"%2$s\"; \n\
936 s->progs[%1$zu].prog = &obj->progs.%2$s;\n\
937 s->progs[%1$zu].link = &obj->links.%2$s;\n\
939 i, bpf_program__name(prog));
947 s->data = (void *)\"\\ \n\
951 /* embed contents of BPF object file */
952 print_hex(obj_data, file_sz);
960 bpf_object__destroy_skeleton(s); \n\
969 bpf_object__close(obj);
971 munmap(obj_data, mmap_sz);
976 static int do_object(int argc, char **argv)
978 struct bpf_linker *linker;
979 const char *output_file, *file;
987 output_file = GET_ARG();
989 linker = bpf_linker__new(output_file, NULL);
991 p_err("failed to create BPF linker instance");
998 err = bpf_linker__add_file(linker, file, NULL);
1000 p_err("failed to link '%s': %s (%d)", file, strerror(err), err);
1005 err = bpf_linker__finalize(linker);
1007 p_err("failed to finalize ELF file: %s (%d)", strerror(err), err);
1013 bpf_linker__free(linker);
1017 static int do_help(int argc, char **argv)
1020 jsonw_null(json_wtr);
1025 "Usage: %1$s %2$s object OUTPUT_FILE INPUT_FILE [INPUT_FILE...]\n"
1026 " %1$s %2$s skeleton FILE [name OBJECT_NAME]\n"
1029 " " HELP_SPEC_OPTIONS "\n"
1036 static const struct cmd cmds[] = {
1037 { "object", do_object },
1038 { "skeleton", do_skeleton },
1039 { "help", do_help },
1043 int do_gen(int argc, char **argv)
1045 return cmd_select(cmds, argc, argv, do_help);