blob: 7443879e87afea37122ff4914f10f982a7f3e7df [file] [log] [blame]
// 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);
if (n)
exit(-1);
}
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);
}