622 lines
14 KiB
C
622 lines
14 KiB
C
// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
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/* Copyright (C) 2019 Facebook */
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#ifndef _GNU_SOURCE
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#define _GNU_SOURCE
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#endif
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#include <ctype.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <linux/err.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <bpf/bpf.h>
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#include <bpf/libbpf.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/mman.h>
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#include <bpf/btf.h>
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#include "json_writer.h"
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#include "main.h"
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#define MAX_OBJ_NAME_LEN 64
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static void sanitize_identifier(char *name)
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{
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int i;
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for (i = 0; name[i]; i++)
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if (!isalnum(name[i]) && name[i] != '_')
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name[i] = '_';
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}
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static bool str_has_suffix(const char *str, const char *suffix)
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{
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size_t i, n1 = strlen(str), n2 = strlen(suffix);
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if (n1 < n2)
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return false;
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for (i = 0; i < n2; i++) {
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if (str[n1 - i - 1] != suffix[n2 - i - 1])
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return false;
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}
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return true;
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}
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static void get_obj_name(char *name, const char *file)
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{
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/* Using basename() GNU version which doesn't modify arg. */
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strncpy(name, basename(file), MAX_OBJ_NAME_LEN - 1);
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name[MAX_OBJ_NAME_LEN - 1] = '\0';
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if (str_has_suffix(name, ".o"))
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name[strlen(name) - 2] = '\0';
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sanitize_identifier(name);
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}
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static void get_header_guard(char *guard, const char *obj_name)
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{
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int i;
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sprintf(guard, "__%s_SKEL_H__", obj_name);
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for (i = 0; guard[i]; i++)
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guard[i] = toupper(guard[i]);
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}
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static const char *get_map_ident(const struct bpf_map *map)
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{
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const char *name = bpf_map__name(map);
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if (!bpf_map__is_internal(map))
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return name;
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if (str_has_suffix(name, ".data"))
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return "data";
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else if (str_has_suffix(name, ".rodata"))
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return "rodata";
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else if (str_has_suffix(name, ".bss"))
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return "bss";
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else if (str_has_suffix(name, ".kconfig"))
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return "kconfig";
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else
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return NULL;
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}
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static void codegen_btf_dump_printf(void *ctx, const char *fmt, va_list args)
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{
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vprintf(fmt, args);
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}
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static int codegen_datasec_def(struct bpf_object *obj,
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struct btf *btf,
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struct btf_dump *d,
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const struct btf_type *sec,
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const char *obj_name)
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{
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const char *sec_name = btf__name_by_offset(btf, sec->name_off);
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const struct btf_var_secinfo *sec_var = btf_var_secinfos(sec);
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int i, err, off = 0, pad_cnt = 0, vlen = btf_vlen(sec);
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const char *sec_ident;
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char var_ident[256];
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bool strip_mods = false;
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if (strcmp(sec_name, ".data") == 0) {
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sec_ident = "data";
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} else if (strcmp(sec_name, ".bss") == 0) {
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sec_ident = "bss";
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} else if (strcmp(sec_name, ".rodata") == 0) {
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sec_ident = "rodata";
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strip_mods = true;
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} else if (strcmp(sec_name, ".kconfig") == 0) {
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sec_ident = "kconfig";
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} else {
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return 0;
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}
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printf(" struct %s__%s {\n", obj_name, sec_ident);
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for (i = 0; i < vlen; i++, sec_var++) {
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const struct btf_type *var = btf__type_by_id(btf, sec_var->type);
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const char *var_name = btf__name_by_offset(btf, var->name_off);
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DECLARE_LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts,
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.field_name = var_ident,
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.indent_level = 2,
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.strip_mods = strip_mods,
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);
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int need_off = sec_var->offset, align_off, align;
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__u32 var_type_id = var->type;
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if (off > need_off) {
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p_err("Something is wrong for %s's variable #%d: need offset %d, already at %d.\n",
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sec_name, i, need_off, off);
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return -EINVAL;
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}
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align = btf__align_of(btf, var->type);
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if (align <= 0) {
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p_err("Failed to determine alignment of variable '%s': %d",
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var_name, align);
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return -EINVAL;
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}
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/* Assume 32-bit architectures when generating data section
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* struct memory layout. Given bpftool can't know which target
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* host architecture it's emitting skeleton for, we need to be
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* conservative and assume 32-bit one to ensure enough padding
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* bytes are generated for pointer and long types. This will
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* still work correctly for 64-bit architectures, because in
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* the worst case we'll generate unnecessary padding field,
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* which on 64-bit architectures is not strictly necessary and
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* would be handled by natural 8-byte alignment. But it still
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* will be a correct memory layout, based on recorded offsets
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* in BTF.
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*/
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if (align > 4)
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align = 4;
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align_off = (off + align - 1) / align * align;
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if (align_off != need_off) {
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printf("\t\tchar __pad%d[%d];\n",
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pad_cnt, need_off - off);
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pad_cnt++;
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}
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/* sanitize variable name, e.g., for static vars inside
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* a function, it's name is '<function name>.<variable name>',
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* which we'll turn into a '<function name>_<variable name>'
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*/
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var_ident[0] = '\0';
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strncat(var_ident, var_name, sizeof(var_ident) - 1);
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sanitize_identifier(var_ident);
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printf("\t\t");
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err = btf_dump__emit_type_decl(d, var_type_id, &opts);
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if (err)
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return err;
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printf(";\n");
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off = sec_var->offset + sec_var->size;
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}
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printf(" } *%s;\n", sec_ident);
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return 0;
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}
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static int codegen_datasecs(struct bpf_object *obj, const char *obj_name)
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{
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struct btf *btf = bpf_object__btf(obj);
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int n = btf__get_nr_types(btf);
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struct btf_dump *d;
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int i, err = 0;
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d = btf_dump__new(btf, NULL, NULL, codegen_btf_dump_printf);
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if (IS_ERR(d))
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return PTR_ERR(d);
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for (i = 1; i <= n; i++) {
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const struct btf_type *t = btf__type_by_id(btf, i);
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if (!btf_is_datasec(t))
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continue;
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err = codegen_datasec_def(obj, btf, d, t, obj_name);
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if (err)
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goto out;
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}
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out:
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btf_dump__free(d);
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return err;
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}
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static void codegen(const char *template, ...)
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{
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const char *src, *end;
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int skip_tabs = 0, n;
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char *s, *dst;
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va_list args;
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char c;
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n = strlen(template);
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s = malloc(n + 1);
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if (!s)
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exit(-1);
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src = template;
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dst = s;
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/* find out "baseline" indentation to skip */
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while ((c = *src++)) {
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if (c == '\t') {
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skip_tabs++;
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} else if (c == '\n') {
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break;
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} else {
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p_err("unrecognized character at pos %td in template '%s'",
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src - template - 1, template);
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free(s);
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exit(-1);
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}
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}
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while (*src) {
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/* skip baseline indentation tabs */
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for (n = skip_tabs; n > 0; n--, src++) {
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if (*src != '\t') {
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p_err("not enough tabs at pos %td in template '%s'",
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src - template - 1, template);
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free(s);
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exit(-1);
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}
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}
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/* trim trailing whitespace */
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end = strchrnul(src, '\n');
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for (n = end - src; n > 0 && isspace(src[n - 1]); n--)
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;
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memcpy(dst, src, n);
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dst += n;
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if (*end)
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*dst++ = '\n';
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src = *end ? end + 1 : end;
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}
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*dst++ = '\0';
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/* print out using adjusted template */
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va_start(args, template);
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n = vprintf(s, args);
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va_end(args);
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free(s);
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}
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static int do_skeleton(int argc, char **argv)
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{
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char header_guard[MAX_OBJ_NAME_LEN + sizeof("__SKEL_H__")];
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size_t i, map_cnt = 0, prog_cnt = 0, file_sz, mmap_sz;
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DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts);
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char obj_name[MAX_OBJ_NAME_LEN], *obj_data;
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struct bpf_object *obj = NULL;
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const char *file, *ident;
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struct bpf_program *prog;
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int fd, len, err = -1;
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struct bpf_map *map;
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struct btf *btf;
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struct stat st;
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if (!REQ_ARGS(1)) {
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usage();
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return -1;
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}
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file = GET_ARG();
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if (argc) {
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p_err("extra unknown arguments");
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return -1;
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}
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if (stat(file, &st)) {
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p_err("failed to stat() %s: %s", file, strerror(errno));
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return -1;
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}
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file_sz = st.st_size;
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mmap_sz = roundup(file_sz, sysconf(_SC_PAGE_SIZE));
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fd = open(file, O_RDONLY);
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if (fd < 0) {
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p_err("failed to open() %s: %s", file, strerror(errno));
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return -1;
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}
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obj_data = mmap(NULL, mmap_sz, PROT_READ, MAP_PRIVATE, fd, 0);
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if (obj_data == MAP_FAILED) {
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obj_data = NULL;
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p_err("failed to mmap() %s: %s", file, strerror(errno));
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goto out;
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}
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get_obj_name(obj_name, file);
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opts.object_name = obj_name;
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obj = bpf_object__open_mem(obj_data, file_sz, &opts);
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if (IS_ERR(obj)) {
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char err_buf[256];
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libbpf_strerror(PTR_ERR(obj), err_buf, sizeof(err_buf));
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p_err("failed to open BPF object file: %s", err_buf);
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obj = NULL;
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goto out;
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}
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bpf_object__for_each_map(map, obj) {
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ident = get_map_ident(map);
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if (!ident) {
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p_err("ignoring unrecognized internal map '%s'...",
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bpf_map__name(map));
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continue;
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}
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map_cnt++;
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}
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bpf_object__for_each_program(prog, obj) {
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prog_cnt++;
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}
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get_header_guard(header_guard, obj_name);
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codegen("\
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\n\
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/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ \n\
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\n\
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/* THIS FILE IS AUTOGENERATED! */ \n\
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#ifndef %2$s \n\
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#define %2$s \n\
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\n\
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#include <stdlib.h> \n\
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#include <bpf/libbpf.h> \n\
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\n\
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struct %1$s { \n\
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struct bpf_object_skeleton *skeleton; \n\
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struct bpf_object *obj; \n\
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",
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obj_name, header_guard
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);
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if (map_cnt) {
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printf("\tstruct {\n");
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bpf_object__for_each_map(map, obj) {
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ident = get_map_ident(map);
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if (!ident)
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continue;
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printf("\t\tstruct bpf_map *%s;\n", ident);
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}
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printf("\t} maps;\n");
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}
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if (prog_cnt) {
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printf("\tstruct {\n");
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bpf_object__for_each_program(prog, obj) {
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printf("\t\tstruct bpf_program *%s;\n",
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bpf_program__name(prog));
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}
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printf("\t} progs;\n");
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printf("\tstruct {\n");
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bpf_object__for_each_program(prog, obj) {
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printf("\t\tstruct bpf_link *%s;\n",
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bpf_program__name(prog));
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}
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printf("\t} links;\n");
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}
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btf = bpf_object__btf(obj);
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if (btf) {
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err = codegen_datasecs(obj, obj_name);
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if (err)
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goto out;
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}
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codegen("\
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\n\
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}; \n\
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\n\
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static void \n\
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%1$s__destroy(struct %1$s *obj) \n\
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{ \n\
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if (!obj) \n\
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return; \n\
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if (obj->skeleton) \n\
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bpf_object__destroy_skeleton(obj->skeleton);\n\
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free(obj); \n\
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} \n\
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\n\
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static inline int \n\
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%1$s__create_skeleton(struct %1$s *obj); \n\
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\n\
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static inline struct %1$s * \n\
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%1$s__open_opts(const struct bpf_object_open_opts *opts) \n\
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{ \n\
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struct %1$s *obj; \n\
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\n\
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obj = (struct %1$s *)calloc(1, sizeof(*obj)); \n\
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if (!obj) \n\
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return NULL; \n\
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if (%1$s__create_skeleton(obj)) \n\
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goto err; \n\
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if (bpf_object__open_skeleton(obj->skeleton, opts)) \n\
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goto err; \n\
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\n\
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return obj; \n\
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err: \n\
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%1$s__destroy(obj); \n\
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return NULL; \n\
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} \n\
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\n\
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static inline struct %1$s * \n\
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%1$s__open(void) \n\
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{ \n\
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return %1$s__open_opts(NULL); \n\
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} \n\
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\n\
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static inline int \n\
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%1$s__load(struct %1$s *obj) \n\
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{ \n\
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return bpf_object__load_skeleton(obj->skeleton); \n\
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} \n\
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\n\
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static inline struct %1$s * \n\
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%1$s__open_and_load(void) \n\
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{ \n\
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struct %1$s *obj; \n\
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\n\
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obj = %1$s__open(); \n\
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if (!obj) \n\
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return NULL; \n\
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if (%1$s__load(obj)) { \n\
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%1$s__destroy(obj); \n\
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return NULL; \n\
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} \n\
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return obj; \n\
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} \n\
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\n\
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static inline int \n\
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%1$s__attach(struct %1$s *obj) \n\
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{ \n\
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return bpf_object__attach_skeleton(obj->skeleton); \n\
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} \n\
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\n\
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static inline void \n\
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%1$s__detach(struct %1$s *obj) \n\
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{ \n\
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return bpf_object__detach_skeleton(obj->skeleton); \n\
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} \n\
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",
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obj_name
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);
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codegen("\
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\n\
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\n\
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static inline int \n\
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%1$s__create_skeleton(struct %1$s *obj) \n\
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{ \n\
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struct bpf_object_skeleton *s; \n\
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\n\
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s = (struct bpf_object_skeleton *)calloc(1, sizeof(*s));\n\
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if (!s) \n\
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return -1; \n\
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obj->skeleton = s; \n\
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\n\
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s->sz = sizeof(*s); \n\
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s->name = \"%1$s\"; \n\
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s->obj = &obj->obj; \n\
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",
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obj_name
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);
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if (map_cnt) {
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codegen("\
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\n\
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\n\
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/* maps */ \n\
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s->map_cnt = %zu; \n\
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s->map_skel_sz = sizeof(*s->maps); \n\
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s->maps = (struct bpf_map_skeleton *)calloc(s->map_cnt, s->map_skel_sz);\n\
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if (!s->maps) \n\
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goto err; \n\
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",
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map_cnt
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);
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i = 0;
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bpf_object__for_each_map(map, obj) {
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ident = get_map_ident(map);
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if (!ident)
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continue;
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codegen("\
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\n\
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\n\
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s->maps[%zu].name = \"%s\"; \n\
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s->maps[%zu].map = &obj->maps.%s; \n\
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",
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i, bpf_map__name(map), i, ident);
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/* memory-mapped internal maps */
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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 = (struct bpf_prog_skeleton *)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);
|
|
}
|