bpf/prog_tests/btf_split.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /* Copyright (c) 2020 Facebook */
0003 #include <test_progs.h>
0004 #include <bpf/btf.h>
0005
0006 static char *dump_buf;
0007 static size_t dump_buf_sz;
0008 static FILE *dump_buf_file;
0009
0010 static void btf_dump_printf(void *ctx, const char *fmt, va_list args)
0011 {
0012     vfprintf(ctx, fmt, args);
0013 }
0014
0015 void test_btf_split() {
0016     struct btf_dump *d = NULL;
0017     const struct btf_type *t;
0018     struct btf *btf1, *btf2;
0019     int str_off, i, err;
0020
0021     btf1 = btf__new_empty();
0022     if (!ASSERT_OK_PTR(btf1, "empty_main_btf"))
0023         return;
0024
0025     btf__set_pointer_size(btf1, 8); /* enforce 64-bit arch */
0026
0027     btf__add_int(btf1, "int", 4, BTF_INT_SIGNED);   /* [1] int */
0028     btf__add_ptr(btf1, 1);              /* [2] ptr to int */
0029
0030     btf__add_struct(btf1, "s1", 4);         /* [3] struct s1 { */
0031     btf__add_field(btf1, "f1", 1, 0, 0);        /*      int f1; */
0032                             /* } */
0033
0034     btf2 = btf__new_empty_split(btf1);
0035     if (!ASSERT_OK_PTR(btf2, "empty_split_btf"))
0036         goto cleanup;
0037
0038     /* pointer size should be "inherited" from main BTF */
0039     ASSERT_EQ(btf__pointer_size(btf2), 8, "inherit_ptr_sz");
0040
0041     str_off = btf__find_str(btf2, "int");
0042     ASSERT_NEQ(str_off, -ENOENT, "str_int_missing");
0043
0044     t = btf__type_by_id(btf2, 1);
0045     if (!ASSERT_OK_PTR(t, "int_type"))
0046         goto cleanup;
0047     ASSERT_EQ(btf_is_int(t), true, "int_kind");
0048     ASSERT_STREQ(btf__str_by_offset(btf2, t->name_off), "int", "int_name");
0049
0050     btf__add_struct(btf2, "s2", 16);        /* [4] struct s2 {  */
0051     btf__add_field(btf2, "f1", 3, 0, 0);        /*      struct s1 f1;   */
0052     btf__add_field(btf2, "f2", 1, 32, 0);       /*      int f2;     */
0053     btf__add_field(btf2, "f3", 2, 64, 0);       /*      int *f3;    */
0054                             /* } */
0055
0056     t = btf__type_by_id(btf1, 4);
0057     ASSERT_NULL(t, "split_type_in_main");
0058
0059     t = btf__type_by_id(btf2, 4);
0060     if (!ASSERT_OK_PTR(t, "split_struct_type"))
0061         goto cleanup;
0062     ASSERT_EQ(btf_is_struct(t), true, "split_struct_kind");
0063     ASSERT_EQ(btf_vlen(t), 3, "split_struct_vlen");
0064     ASSERT_STREQ(btf__str_by_offset(btf2, t->name_off), "s2", "split_struct_name");
0065
0066     /* BTF-to-C dump of split BTF */
0067     dump_buf_file = open_memstream(&dump_buf, &dump_buf_sz);
0068     if (!ASSERT_OK_PTR(dump_buf_file, "dump_memstream"))
0069         return;
0070     d = btf_dump__new(btf2, btf_dump_printf, dump_buf_file, NULL);
0071     if (!ASSERT_OK_PTR(d, "btf_dump__new"))
0072         goto cleanup;
0073     for (i = 1; i < btf__type_cnt(btf2); i++) {
0074         err = btf_dump__dump_type(d, i);
0075         ASSERT_OK(err, "dump_type_ok");
0076     }
0077     fflush(dump_buf_file);
0078     dump_buf[dump_buf_sz] = 0; /* some libc implementations don't do this */
0079     ASSERT_STREQ(dump_buf,
0080 "struct s1 {\n"
0081 "   int f1;\n"
0082 "};\n"
0083 "\n"
0084 "struct s2 {\n"
0085 "   struct s1 f1;\n"
0086 "   int f2;\n"
0087 "   int *f3;\n"
0088 "};\n\n", "c_dump");
0089
0090 cleanup:
0091     if (dump_buf_file)
0092         fclose(dump_buf_file);
0093     free(dump_buf);
0094     btf_dump__free(d);
0095     btf__free(btf1);
0096     btf__free(btf2);
0097 }