LXR linux/tools/testing/selftests/bpf/prog_tests/btf

   1// SPDX-License-Identifier: GPL-2.0
   2/* Copyright (c) 2020 Facebook */
   3#include <test_progs.h>
   4#include <bpf/btf.h>
   5
   6static char *dump_buf;
   7static size_t dump_buf_sz;
   8static FILE *dump_buf_file;
   9
  10static void btf_dump_printf(void *ctx, const char *fmt, va_list args)
  11{
  12        vfprintf(ctx, fmt, args);
  13}
  14
  15void test_btf_split() {
  16        struct btf_dump_opts opts;
  17        struct btf_dump *d = NULL;
  18        const struct btf_type *t;
  19        struct btf *btf1, *btf2;
  20        int str_off, i, err;
  21
  22        btf1 = btf__new_empty();
  23        if (!ASSERT_OK_PTR(btf1, "empty_main_btf"))
  24                return;
  25
  26        btf__set_pointer_size(btf1, 8); /* enforce 64-bit arch */
  27
  28        btf__add_int(btf1, "int", 4, BTF_INT_SIGNED);   /* [1] int */
  29        btf__add_ptr(btf1, 1);                          /* [2] ptr to int */
  30
  31        btf__add_struct(btf1, "s1", 4);                 /* [3] struct s1 { */
  32        btf__add_field(btf1, "f1", 1, 0, 0);            /*      int f1; */
  33                                                        /* } */
  34
  35        btf2 = btf__new_empty_split(btf1);
  36        if (!ASSERT_OK_PTR(btf2, "empty_split_btf"))
  37                goto cleanup;
  38
  39        /* pointer size should be "inherited" from main BTF */
  40        ASSERT_EQ(btf__pointer_size(btf2), 8, "inherit_ptr_sz");
  41
  42        str_off = btf__find_str(btf2, "int");
  43        ASSERT_NEQ(str_off, -ENOENT, "str_int_missing");
  44
  45        t = btf__type_by_id(btf2, 1);
  46        if (!ASSERT_OK_PTR(t, "int_type"))
  47                goto cleanup;
  48        ASSERT_EQ(btf_is_int(t), true, "int_kind");
  49        ASSERT_STREQ(btf__str_by_offset(btf2, t->name_off), "int", "int_name");
  50
  51        btf__add_struct(btf2, "s2", 16);                /* [4] struct s2 {      */
  52        btf__add_field(btf2, "f1", 3, 0, 0);            /*      struct s1 f1;   */
  53        btf__add_field(btf2, "f2", 1, 32, 0);           /*      int f2;         */
  54        btf__add_field(btf2, "f3", 2, 64, 0);           /*      int *f3;        */
  55                                                        /* } */
  56
  57        t = btf__type_by_id(btf1, 4);
  58        ASSERT_NULL(t, "split_type_in_main");
  59
  60        t = btf__type_by_id(btf2, 4);
  61        if (!ASSERT_OK_PTR(t, "split_struct_type"))
  62                goto cleanup;
  63        ASSERT_EQ(btf_is_struct(t), true, "split_struct_kind");
  64        ASSERT_EQ(btf_vlen(t), 3, "split_struct_vlen");
  65        ASSERT_STREQ(btf__str_by_offset(btf2, t->name_off), "s2", "split_struct_name");
  66
  67        /* BTF-to-C dump of split BTF */
  68        dump_buf_file = open_memstream(&dump_buf, &dump_buf_sz);
  69        if (!ASSERT_OK_PTR(dump_buf_file, "dump_memstream"))
  70                return;
  71        opts.ctx = dump_buf_file;
  72        d = btf_dump__new(btf2, NULL, &opts, btf_dump_printf);
  73        if (!ASSERT_OK_PTR(d, "btf_dump__new"))
  74                goto cleanup;
  75        for (i = 1; i <= btf__get_nr_types(btf2); i++) {
  76                err = btf_dump__dump_type(d, i);
  77                ASSERT_OK(err, "dump_type_ok");
  78        }
  79        fflush(dump_buf_file);
  80        dump_buf[dump_buf_sz] = 0; /* some libc implementations don't do this */
  81        ASSERT_STREQ(dump_buf,
  82"struct s1 {\n"
  83"       int f1;\n"
  84"};\n"
  85"\n"
  86"struct s2 {\n"
  87"       struct s1 f1;\n"
  88"       int f2;\n"
  89"       int *f3;\n"
  90"};\n\n", "c_dump");
  91
  92cleanup:
  93        if (dump_buf_file)
  94                fclose(dump_buf_file);
  95        free(dump_buf);
  96        btf_dump__free(d);
  97        btf__free(btf1);
  98        btf__free(btf2);
  99}
 100