tools/testing/selftests/bpf/prog_tests/btf_split.c

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