bpf/prog_tests/resolve_btfids.c

0001 // SPDX-License-Identifier: GPL-2.0
0002
0003 #include <linux/err.h>
0004 #include <string.h>
0005 #include <bpf/btf.h>
0006 #include <bpf/libbpf.h>
0007 #include <linux/btf.h>
0008 #include <linux/kernel.h>
0009 #define CONFIG_DEBUG_INFO_BTF
0010 #include <linux/btf_ids.h>
0011 #include "test_progs.h"
0012
0013 static int duration;
0014
0015 struct symbol {
0016     const char  *name;
0017     int      type;
0018     int      id;
0019 };
0020
0021 struct symbol test_symbols[] = {
0022     { "unused",  BTF_KIND_UNKN,     0 },
0023     { "S",       BTF_KIND_TYPEDEF, -1 },
0024     { "T",       BTF_KIND_TYPEDEF, -1 },
0025     { "U",       BTF_KIND_TYPEDEF, -1 },
0026     { "S",       BTF_KIND_STRUCT,  -1 },
0027     { "U",       BTF_KIND_UNION,   -1 },
0028     { "func",    BTF_KIND_FUNC,    -1 },
0029 };
0030
0031 /* Align the .BTF_ids section to 4 bytes */
0032 asm (
0033 ".pushsection " BTF_IDS_SECTION " ,\"a\"; \n"
0034 ".balign 4, 0;                            \n"
0035 ".popsection;                             \n");
0036
0037 BTF_ID_LIST(test_list_local)
0038 BTF_ID_UNUSED
0039 BTF_ID(typedef, S)
0040 BTF_ID(typedef, T)
0041 BTF_ID(typedef, U)
0042 BTF_ID(struct,  S)
0043 BTF_ID(union,   U)
0044 BTF_ID(func,    func)
0045
0046 extern __u32 test_list_global[];
0047 BTF_ID_LIST_GLOBAL(test_list_global, 1)
0048 BTF_ID_UNUSED
0049 BTF_ID(typedef, S)
0050 BTF_ID(typedef, T)
0051 BTF_ID(typedef, U)
0052 BTF_ID(struct,  S)
0053 BTF_ID(union,   U)
0054 BTF_ID(func,    func)
0055
0056 BTF_SET_START(test_set)
0057 BTF_ID(typedef, S)
0058 BTF_ID(typedef, T)
0059 BTF_ID(typedef, U)
0060 BTF_ID(struct,  S)
0061 BTF_ID(union,   U)
0062 BTF_ID(func,    func)
0063 BTF_SET_END(test_set)
0064
0065 static int
0066 __resolve_symbol(struct btf *btf, int type_id)
0067 {
0068     const struct btf_type *type;
0069     const char *str;
0070     unsigned int i;
0071
0072     type = btf__type_by_id(btf, type_id);
0073     if (!type) {
0074         PRINT_FAIL("Failed to get type for ID %d\n", type_id);
0075         return -1;
0076     }
0077
0078     for (i = 0; i < ARRAY_SIZE(test_symbols); i++) {
0079         if (test_symbols[i].id >= 0)
0080             continue;
0081
0082         if (BTF_INFO_KIND(type->info) != test_symbols[i].type)
0083             continue;
0084
0085         str = btf__name_by_offset(btf, type->name_off);
0086         if (!str) {
0087             PRINT_FAIL("Failed to get name for BTF ID %d\n", type_id);
0088             return -1;
0089         }
0090
0091         if (!strcmp(str, test_symbols[i].name))
0092             test_symbols[i].id = type_id;
0093     }
0094
0095     return 0;
0096 }
0097
0098 static int resolve_symbols(void)
0099 {
0100     struct btf *btf;
0101     int type_id;
0102     __u32 nr;
0103
0104     btf = btf__parse_elf("btf_data.o", NULL);
0105     if (CHECK(libbpf_get_error(btf), "resolve",
0106           "Failed to load BTF from btf_data.o\n"))
0107         return -1;
0108
0109     nr = btf__type_cnt(btf);
0110
0111     for (type_id = 1; type_id < nr; type_id++) {
0112         if (__resolve_symbol(btf, type_id))
0113             break;
0114     }
0115
0116     btf__free(btf);
0117     return 0;
0118 }
0119
0120 void test_resolve_btfids(void)
0121 {
0122     __u32 *test_list, *test_lists[] = { test_list_local, test_list_global };
0123     unsigned int i, j;
0124     int ret = 0;
0125
0126     if (resolve_symbols())
0127         return;
0128
0129     /* Check BTF_ID_LIST(test_list_local) and
0130      * BTF_ID_LIST_GLOBAL(test_list_global) IDs
0131      */
0132     for (j = 0; j < ARRAY_SIZE(test_lists); j++) {
0133         test_list = test_lists[j];
0134         for (i = 0; i < ARRAY_SIZE(test_symbols); i++) {
0135             ret = CHECK(test_list[i] != test_symbols[i].id,
0136                     "id_check",
0137                     "wrong ID for %s (%d != %d)\n",
0138                     test_symbols[i].name,
0139                     test_list[i], test_symbols[i].id);
0140             if (ret)
0141                 return;
0142         }
0143     }
0144
0145     /* Check BTF_SET_START(test_set) IDs */
0146     for (i = 0; i < test_set.cnt; i++) {
0147         bool found = false;
0148
0149         for (j = 0; j < ARRAY_SIZE(test_symbols); j++) {
0150             if (test_symbols[j].id != test_set.ids[i])
0151                 continue;
0152             found = true;
0153             break;
0154         }
0155
0156         ret = CHECK(!found, "id_check",
0157                 "ID %d not found in test_symbols\n",
0158                 test_set.ids[i]);
0159         if (ret)
0160             break;
0161
0162         if (i > 0) {
0163             if (!ASSERT_LE(test_set.ids[i - 1], test_set.ids[i], "sort_check"))
0164                 return;
0165         }
0166     }
0167 }