/tools/bpf/bpftool/gen.c
C | 609 lines | 537 code | 59 blank | 13 comment | 77 complexity | d587898d47d826bd4de705f8e2c9c947 MD5 | raw file
Possible License(s): LGPL-2.0, AGPL-1.0, GPL-2.0
- // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
- /* Copyright (C) 2019 Facebook */
- #ifndef _GNU_SOURCE
- #define _GNU_SOURCE
- #endif
- #include <ctype.h>
- #include <errno.h>
- #include <fcntl.h>
- #include <linux/err.h>
- #include <stdbool.h>
- #include <stdio.h>
- #include <string.h>
- #include <unistd.h>
- #include <bpf/bpf.h>
- #include <bpf/libbpf.h>
- #include <sys/types.h>
- #include <sys/stat.h>
- #include <sys/mman.h>
- #include <bpf/btf.h>
- #include "bpf/libbpf_internal.h"
- #include "json_writer.h"
- #include "main.h"
- #define MAX_OBJ_NAME_LEN 64
- static void sanitize_identifier(char *name)
- {
- int i;
- for (i = 0; name[i]; i++)
- if (!isalnum(name[i]) && name[i] != '_')
- name[i] = '_';
- }
- static bool str_has_suffix(const char *str, const char *suffix)
- {
- size_t i, n1 = strlen(str), n2 = strlen(suffix);
- if (n1 < n2)
- return false;
- for (i = 0; i < n2; i++) {
- if (str[n1 - i - 1] != suffix[n2 - i - 1])
- return false;
- }
- return true;
- }
- static void get_obj_name(char *name, const char *file)
- {
- /* Using basename() GNU version which doesn't modify arg. */
- strncpy(name, basename(file), MAX_OBJ_NAME_LEN - 1);
- name[MAX_OBJ_NAME_LEN - 1] = '\0';
- if (str_has_suffix(name, ".o"))
- name[strlen(name) - 2] = '\0';
- sanitize_identifier(name);
- }
- static void get_header_guard(char *guard, const char *obj_name)
- {
- int i;
- sprintf(guard, "__%s_SKEL_H__", obj_name);
- for (i = 0; guard[i]; i++)
- guard[i] = toupper(guard[i]);
- }
- static const char *get_map_ident(const struct bpf_map *map)
- {
- const char *name = bpf_map__name(map);
- if (!bpf_map__is_internal(map))
- return name;
- if (str_has_suffix(name, ".data"))
- return "data";
- else if (str_has_suffix(name, ".rodata"))
- return "rodata";
- else if (str_has_suffix(name, ".bss"))
- return "bss";
- else if (str_has_suffix(name, ".kconfig"))
- return "kconfig";
- else
- return NULL;
- }
- static void codegen_btf_dump_printf(void *ct, const char *fmt, va_list args)
- {
- vprintf(fmt, args);
- }
- static int codegen_datasec_def(struct bpf_object *obj,
- struct btf *btf,
- struct btf_dump *d,
- const struct btf_type *sec,
- const char *obj_name)
- {
- const char *sec_name = btf__name_by_offset(btf, sec->name_off);
- const struct btf_var_secinfo *sec_var = btf_var_secinfos(sec);
- int i, err, off = 0, pad_cnt = 0, vlen = btf_vlen(sec);
- const char *sec_ident;
- char var_ident[256];
- if (strcmp(sec_name, ".data") == 0)
- sec_ident = "data";
- else if (strcmp(sec_name, ".bss") == 0)
- sec_ident = "bss";
- else if (strcmp(sec_name, ".rodata") == 0)
- sec_ident = "rodata";
- else if (strcmp(sec_name, ".kconfig") == 0)
- sec_ident = "kconfig";
- else
- return 0;
- printf(" struct %s__%s {\n", obj_name, sec_ident);
- for (i = 0; i < vlen; i++, sec_var++) {
- const struct btf_type *var = btf__type_by_id(btf, sec_var->type);
- const char *var_name = btf__name_by_offset(btf, var->name_off);
- DECLARE_LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts,
- .field_name = var_ident,
- .indent_level = 2,
- );
- int need_off = sec_var->offset, align_off, align;
- __u32 var_type_id = var->type;
- const struct btf_type *t;
- t = btf__type_by_id(btf, var_type_id);
- while (btf_is_mod(t)) {
- var_type_id = t->type;
- t = btf__type_by_id(btf, var_type_id);
- }
- if (off > need_off) {
- p_err("Something is wrong for %s's variable #%d: need offset %d, already at %d.\n",
- sec_name, i, need_off, off);
- return -EINVAL;
- }
- align = btf__align_of(btf, var->type);
- if (align <= 0) {
- p_err("Failed to determine alignment of variable '%s': %d",
- var_name, align);
- return -EINVAL;
- }
- align_off = (off + align - 1) / align * align;
- if (align_off != need_off) {
- printf("\t\tchar __pad%d[%d];\n",
- pad_cnt, need_off - off);
- pad_cnt++;
- }
- /* sanitize variable name, e.g., for static vars inside
- * a function, it's name is '<function name>.<variable name>',
- * which we'll turn into a '<function name>_<variable name>'
- */
- var_ident[0] = '\0';
- strncat(var_ident, var_name, sizeof(var_ident) - 1);
- sanitize_identifier(var_ident);
- printf("\t\t");
- err = btf_dump__emit_type_decl(d, var_type_id, &opts);
- if (err)
- return err;
- printf(";\n");
- off = sec_var->offset + sec_var->size;
- }
- printf(" } *%s;\n", sec_ident);
- return 0;
- }
- static int codegen_datasecs(struct bpf_object *obj, const char *obj_name)
- {
- struct btf *btf = bpf_object__btf(obj);
- int n = btf__get_nr_types(btf);
- struct btf_dump *d;
- int i, err = 0;
- d = btf_dump__new(btf, NULL, NULL, codegen_btf_dump_printf);
- if (IS_ERR(d))
- return PTR_ERR(d);
- for (i = 1; i <= n; i++) {
- const struct btf_type *t = btf__type_by_id(btf, i);
- if (!btf_is_datasec(t))
- continue;
- err = codegen_datasec_def(obj, btf, d, t, obj_name);
- if (err)
- goto out;
- }
- out:
- btf_dump__free(d);
- return err;
- }
- static void codegen(const char *template, ...)
- {
- const char *src, *end;
- int skip_tabs = 0, n;
- char *s, *dst;
- va_list args;
- char c;
- n = strlen(template);
- s = malloc(n + 1);
- if (!s)
- exit(-1);
- src = template;
- dst = s;
- /* find out "baseline" indentation to skip */
- while ((c = *src++)) {
- if (c == '\t') {
- skip_tabs++;
- } else if (c == '\n') {
- break;
- } else {
- p_err("unrecognized character at pos %td in template '%s'",
- src - template - 1, template);
- free(s);
- exit(-1);
- }
- }
- while (*src) {
- /* skip baseline indentation tabs */
- for (n = skip_tabs; n > 0; n--, src++) {
- if (*src != '\t') {
- p_err("not enough tabs at pos %td in template '%s'",
- src - template - 1, template);
- free(s);
- exit(-1);
- }
- }
- /* trim trailing whitespace */
- end = strchrnul(src, '\n');
- for (n = end - src; n > 0 && isspace(src[n - 1]); n--)
- ;
- memcpy(dst, src, n);
- dst += n;
- if (*end)
- *dst++ = '\n';
- src = *end ? end + 1 : end;
- }
- *dst++ = '\0';
- /* print out using adjusted template */
- va_start(args, template);
- n = vprintf(s, args);
- va_end(args);
- free(s);
- }
- static int do_skeleton(int argc, char **argv)
- {
- char header_guard[MAX_OBJ_NAME_LEN + sizeof("__SKEL_H__")];
- size_t i, map_cnt = 0, prog_cnt = 0, file_sz, mmap_sz;
- DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts);
- char obj_name[MAX_OBJ_NAME_LEN], *obj_data;
- struct bpf_object *obj = NULL;
- const char *file, *ident;
- struct bpf_program *prog;
- int fd, len, err = -1;
- struct bpf_map *map;
- struct btf *btf;
- struct stat st;
- if (!REQ_ARGS(1)) {
- usage();
- return -1;
- }
- file = GET_ARG();
- if (argc) {
- p_err("extra unknown arguments");
- return -1;
- }
- if (stat(file, &st)) {
- p_err("failed to stat() %s: %s", file, strerror(errno));
- return -1;
- }
- file_sz = st.st_size;
- mmap_sz = roundup(file_sz, sysconf(_SC_PAGE_SIZE));
- fd = open(file, O_RDONLY);
- if (fd < 0) {
- p_err("failed to open() %s: %s", file, strerror(errno));
- return -1;
- }
- obj_data = mmap(NULL, mmap_sz, PROT_READ, MAP_PRIVATE, fd, 0);
- if (obj_data == MAP_FAILED) {
- obj_data = NULL;
- p_err("failed to mmap() %s: %s", file, strerror(errno));
- goto out;
- }
- get_obj_name(obj_name, file);
- opts.object_name = obj_name;
- obj = bpf_object__open_mem(obj_data, file_sz, &opts);
- if (IS_ERR(obj)) {
- obj = NULL;
- p_err("failed to open BPF object file: %ld", PTR_ERR(obj));
- goto out;
- }
- bpf_object__for_each_map(map, obj) {
- ident = get_map_ident(map);
- if (!ident) {
- p_err("ignoring unrecognized internal map '%s'...",
- bpf_map__name(map));
- continue;
- }
- map_cnt++;
- }
- bpf_object__for_each_program(prog, obj) {
- prog_cnt++;
- }
- get_header_guard(header_guard, obj_name);
- codegen("\
- \n\
- /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ \n\
- \n\
- /* THIS FILE IS AUTOGENERATED! */ \n\
- #ifndef %2$s \n\
- #define %2$s \n\
- \n\
- #include <stdlib.h> \n\
- #include <bpf/libbpf.h> \n\
- \n\
- struct %1$s { \n\
- struct bpf_object_skeleton *skeleton; \n\
- struct bpf_object *obj; \n\
- ",
- obj_name, header_guard
- );
- if (map_cnt) {
- printf("\tstruct {\n");
- bpf_object__for_each_map(map, obj) {
- ident = get_map_ident(map);
- if (!ident)
- continue;
- printf("\t\tstruct bpf_map *%s;\n", ident);
- }
- printf("\t} maps;\n");
- }
- if (prog_cnt) {
- printf("\tstruct {\n");
- bpf_object__for_each_program(prog, obj) {
- printf("\t\tstruct bpf_program *%s;\n",
- bpf_program__name(prog));
- }
- printf("\t} progs;\n");
- printf("\tstruct {\n");
- bpf_object__for_each_program(prog, obj) {
- printf("\t\tstruct bpf_link *%s;\n",
- bpf_program__name(prog));
- }
- printf("\t} links;\n");
- }
- btf = bpf_object__btf(obj);
- if (btf) {
- err = codegen_datasecs(obj, obj_name);
- if (err)
- goto out;
- }
- codegen("\
- \n\
- }; \n\
- \n\
- static void \n\
- %1$s__destroy(struct %1$s *obj) \n\
- { \n\
- if (!obj) \n\
- return; \n\
- if (obj->skeleton) \n\
- bpf_object__destroy_skeleton(obj->skeleton);\n\
- free(obj); \n\
- } \n\
- \n\
- static inline int \n\
- %1$s__create_skeleton(struct %1$s *obj); \n\
- \n\
- static inline struct %1$s * \n\
- %1$s__open_opts(const struct bpf_object_open_opts *opts) \n\
- { \n\
- struct %1$s *obj; \n\
- \n\
- obj = (typeof(obj))calloc(1, sizeof(*obj)); \n\
- if (!obj) \n\
- return NULL; \n\
- if (%1$s__create_skeleton(obj)) \n\
- goto err; \n\
- if (bpf_object__open_skeleton(obj->skeleton, opts)) \n\
- goto err; \n\
- \n\
- return obj; \n\
- err: \n\
- %1$s__destroy(obj); \n\
- return NULL; \n\
- } \n\
- \n\
- static inline struct %1$s * \n\
- %1$s__open(void) \n\
- { \n\
- return %1$s__open_opts(NULL); \n\
- } \n\
- \n\
- static inline int \n\
- %1$s__load(struct %1$s *obj) \n\
- { \n\
- return bpf_object__load_skeleton(obj->skeleton); \n\
- } \n\
- \n\
- static inline struct %1$s * \n\
- %1$s__open_and_load(void) \n\
- { \n\
- struct %1$s *obj; \n\
- \n\
- obj = %1$s__open(); \n\
- if (!obj) \n\
- return NULL; \n\
- if (%1$s__load(obj)) { \n\
- %1$s__destroy(obj); \n\
- return NULL; \n\
- } \n\
- return obj; \n\
- } \n\
- \n\
- static inline int \n\
- %1$s__attach(struct %1$s *obj) \n\
- { \n\
- return bpf_object__attach_skeleton(obj->skeleton); \n\
- } \n\
- \n\
- static inline void \n\
- %1$s__detach(struct %1$s *obj) \n\
- { \n\
- return bpf_object__detach_skeleton(obj->skeleton); \n\
- } \n\
- ",
- obj_name
- );
- codegen("\
- \n\
- \n\
- static inline int \n\
- %1$s__create_skeleton(struct %1$s *obj) \n\
- { \n\
- struct bpf_object_skeleton *s; \n\
- \n\
- s = (typeof(s))calloc(1, sizeof(*s)); \n\
- if (!s) \n\
- return -1; \n\
- obj->skeleton = s; \n\
- \n\
- s->sz = sizeof(*s); \n\
- s->name = \"%1$s\"; \n\
- s->obj = &obj->obj; \n\
- ",
- obj_name
- );
- if (map_cnt) {
- codegen("\
- \n\
- \n\
- /* maps */ \n\
- s->map_cnt = %zu; \n\
- s->map_skel_sz = sizeof(*s->maps); \n\
- s->maps = (typeof(s->maps))calloc(s->map_cnt, s->map_skel_sz);\n\
- if (!s->maps) \n\
- goto err; \n\
- ",
- map_cnt
- );
- i = 0;
- bpf_object__for_each_map(map, obj) {
- ident = get_map_ident(map);
- if (!ident)
- continue;
- codegen("\
- \n\
- \n\
- s->maps[%zu].name = \"%s\"; \n\
- s->maps[%zu].map = &obj->maps.%s; \n\
- ",
- i, bpf_map__name(map), i, ident);
- /* memory-mapped internal maps */
- if (bpf_map__is_internal(map) &&
- (bpf_map__def(map)->map_flags & BPF_F_MMAPABLE)) {
- printf("\ts->maps[%zu].mmaped = (void **)&obj->%s;\n",
- i, ident);
- }
- i++;
- }
- }
- if (prog_cnt) {
- codegen("\
- \n\
- \n\
- /* programs */ \n\
- s->prog_cnt = %zu; \n\
- s->prog_skel_sz = sizeof(*s->progs); \n\
- s->progs = (typeof(s->progs))calloc(s->prog_cnt, s->prog_skel_sz);\n\
- if (!s->progs) \n\
- goto err; \n\
- ",
- prog_cnt
- );
- i = 0;
- bpf_object__for_each_program(prog, obj) {
- codegen("\
- \n\
- \n\
- s->progs[%1$zu].name = \"%2$s\"; \n\
- s->progs[%1$zu].prog = &obj->progs.%2$s;\n\
- s->progs[%1$zu].link = &obj->links.%2$s;\n\
- ",
- i, bpf_program__name(prog));
- i++;
- }
- }
- codegen("\
- \n\
- \n\
- s->data_sz = %d; \n\
- s->data = (void *)\"\\ \n\
- ",
- file_sz);
- /* embed contents of BPF object file */
- for (i = 0, len = 0; i < file_sz; i++) {
- int w = obj_data[i] ? 4 : 2;
- len += w;
- if (len > 78) {
- printf("\\\n");
- len = w;
- }
- if (!obj_data[i])
- printf("\\0");
- else
- printf("\\x%02x", (unsigned char)obj_data[i]);
- }
- codegen("\
- \n\
- \"; \n\
- \n\
- return 0; \n\
- err: \n\
- bpf_object__destroy_skeleton(s); \n\
- return -1; \n\
- } \n\
- \n\
- #endif /* %s */ \n\
- ",
- header_guard);
- err = 0;
- out:
- bpf_object__close(obj);
- if (obj_data)
- munmap(obj_data, mmap_sz);
- close(fd);
- return err;
- }
- static int do_help(int argc, char **argv)
- {
- if (json_output) {
- jsonw_null(json_wtr);
- return 0;
- }
- fprintf(stderr,
- "Usage: %1$s %2$s skeleton FILE\n"
- " %1$s %2$s help\n"
- "\n"
- " " HELP_SPEC_OPTIONS "\n"
- "",
- bin_name, "gen");
- return 0;
- }
- static const struct cmd cmds[] = {
- { "skeleton", do_skeleton },
- { "help", do_help },
- { 0 }
- };
- int do_gen(int argc, char **argv)
- {
- return cmd_select(cmds, argc, argv, do_help);
- }