selftests/bpf: Add btf_field_iter selftests

The added selftests verify that for every BTF kind we iterate correctly
over consituent strings and ids.

Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240605153314.3727466-1-alan.maguire@oracle.com

diff --git a/tools/testing/selftests/bpf/prog_tests/btf_field_iter.c b/tools/testing/selftests/bpf/prog_tests/btf_field_iter.c
new file mode 100644 (file)
index 0000000..32159d3
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/btf_field_iter.c
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024, Oracle and/or its affiliates. */
+
+#include <test_progs.h>
+#include <bpf/btf.h>
+#include "btf_helpers.h"
+#include "bpf/libbpf_internal.h"
+
+struct field_data {
+       __u32 ids[5];
+       const char *strs[5];
+} fields[] = {
+       { .ids = {},            .strs = {} },
+       { .ids = {},            .strs = { "int" } },
+       { .ids = {},            .strs = { "int64" } },
+       { .ids = { 1 },         .strs = { "" } },
+       { .ids = { 2, 1 },      .strs = { "" } },
+       { .ids = { 3, 1 },      .strs = { "s1", "f1", "f2" } },
+       { .ids = { 1, 5 },      .strs = { "u1", "f1", "f2" } },
+       { .ids = {},            .strs = { "e1", "v1", "v2" } },
+       { .ids = {},            .strs = { "fw1" } },
+       { .ids = { 1 },         .strs = { "t" } },
+       { .ids = { 2 },         .strs = { "" } },
+       { .ids = { 1 },         .strs = { "" } },
+       { .ids = { 3 },         .strs = { "" } },
+       { .ids = { 1, 1, 3 },   .strs = { "", "p1", "p2" } },
+       { .ids = { 13 },        .strs = { "func" } },
+       { .ids = { 1 },         .strs = { "var1" } },
+       { .ids = { 3 },         .strs = { "var2" } },
+       { .ids = {},            .strs = { "float" } },
+       { .ids = { 11 },        .strs = { "decltag" } },
+       { .ids = { 6 },         .strs = { "typetag" } },
+       { .ids = {},            .strs = { "e64", "eval1", "eval2", "eval3" } },
+       { .ids = { 15, 16 },    .strs = { "datasec1" } }
+
+};
+
+/* Fabricate BTF with various types and check BTF field iteration finds types,
+ * strings expected.
+ */
+void test_btf_field_iter(void)
+{
+       struct btf *btf = NULL;
+       int id;
+
+       btf = btf__new_empty();
+       if (!ASSERT_OK_PTR(btf, "empty_btf"))
+               return;
+
+       btf__add_int(btf, "int", 4, BTF_INT_SIGNED);    /* [1] int */
+       btf__add_int(btf, "int64", 8, BTF_INT_SIGNED);  /* [2] int64 */
+       btf__add_ptr(btf, 1);                           /* [3] int * */
+       btf__add_array(btf, 1, 2, 3);                   /* [4] int64[3] */
+       btf__add_struct(btf, "s1", 12);                 /* [5] struct s1 { */
+       btf__add_field(btf, "f1", 3, 0, 0);             /*      int *f1; */
+       btf__add_field(btf, "f2", 1, 0, 0);             /*      int f2; */
+                                                       /* } */
+       btf__add_union(btf, "u1", 12);                  /* [6] union u1 { */
+       btf__add_field(btf, "f1", 1, 0, 0);             /*      int f1; */
+       btf__add_field(btf, "f2", 5, 0, 0);             /*      struct s1 f2; */
+                                                       /* } */
+       btf__add_enum(btf, "e1", 4);                    /* [7] enum e1 { */
+       btf__add_enum_value(btf, "v1", 1);              /*      v1 = 1; */
+       btf__add_enum_value(btf, "v2", 2);              /*      v2 = 2; */
+                                                       /* } */
+
+       btf__add_fwd(btf, "fw1", BTF_FWD_STRUCT);       /* [8] struct fw1; */
+       btf__add_typedef(btf, "t", 1);                  /* [9] typedef int t; */
+       btf__add_volatile(btf, 2);                      /* [10] volatile int64; */
+       btf__add_const(btf, 1);                         /* [11] const int; */
+       btf__add_restrict(btf, 3);                      /* [12] restrict int *; */
+       btf__add_func_proto(btf, 1);                    /* [13] int (*)(int p1, int *p2); */
+       btf__add_func_param(btf, "p1", 1);
+       btf__add_func_param(btf, "p2", 3);
+
+       btf__add_func(btf, "func", BTF_FUNC_GLOBAL, 13);/* [14] int func(int p1, int *p2); */
+       btf__add_var(btf, "var1", BTF_VAR_STATIC, 1);   /* [15] static int var1; */
+       btf__add_var(btf, "var2", BTF_VAR_STATIC, 3);   /* [16] static int *var2; */
+       btf__add_float(btf, "float", 4);                /* [17] float; */
+       btf__add_decl_tag(btf, "decltag", 11, -1);      /* [18] decltag const int; */
+       btf__add_type_tag(btf, "typetag", 6);           /* [19] typetag union u1; */
+       btf__add_enum64(btf, "e64", 8, true);           /* [20] enum { */
+       btf__add_enum64_value(btf, "eval1", 1000);      /*       eval1 = 1000, */
+       btf__add_enum64_value(btf, "eval2", 2000);      /*       eval2 = 2000, */
+       btf__add_enum64_value(btf, "eval3", 3000);      /*       eval3 = 3000 */
+                                                       /* } */
+       btf__add_datasec(btf, "datasec1", 12);          /* [21] datasec datasec1 */
+       btf__add_datasec_var_info(btf, 15, 0, 4);
+       btf__add_datasec_var_info(btf, 16, 4, 8);
+
+       VALIDATE_RAW_BTF(
+               btf,
+               "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
+               "[2] INT 'int64' size=8 bits_offset=0 nr_bits=64 encoding=SIGNED",
+               "[3] PTR '(anon)' type_id=1",
+               "[4] ARRAY '(anon)' type_id=2 index_type_id=1 nr_elems=3",
+               "[5] STRUCT 's1' size=12 vlen=2\n"
+               "\t'f1' type_id=3 bits_offset=0\n"
+               "\t'f2' type_id=1 bits_offset=0",
+               "[6] UNION 'u1' size=12 vlen=2\n"
+               "\t'f1' type_id=1 bits_offset=0\n"
+               "\t'f2' type_id=5 bits_offset=0",
+               "[7] ENUM 'e1' encoding=UNSIGNED size=4 vlen=2\n"
+               "\t'v1' val=1\n"
+               "\t'v2' val=2",
+               "[8] FWD 'fw1' fwd_kind=struct",
+               "[9] TYPEDEF 't' type_id=1",
+               "[10] VOLATILE '(anon)' type_id=2",
+               "[11] CONST '(anon)' type_id=1",
+               "[12] RESTRICT '(anon)' type_id=3",
+               "[13] FUNC_PROTO '(anon)' ret_type_id=1 vlen=2\n"
+               "\t'p1' type_id=1\n"
+               "\t'p2' type_id=3",
+               "[14] FUNC 'func' type_id=13 linkage=global",
+               "[15] VAR 'var1' type_id=1, linkage=static",
+               "[16] VAR 'var2' type_id=3, linkage=static",
+               "[17] FLOAT 'float' size=4",
+               "[18] DECL_TAG 'decltag' type_id=11 component_idx=-1",
+               "[19] TYPE_TAG 'typetag' type_id=6",
+               "[20] ENUM64 'e64' encoding=SIGNED size=8 vlen=3\n"
+               "\t'eval1' val=1000\n"
+               "\t'eval2' val=2000\n"
+               "\t'eval3' val=3000",
+               "[21] DATASEC 'datasec1' size=12 vlen=2\n"
+               "\ttype_id=15 offset=0 size=4\n"
+               "\ttype_id=16 offset=4 size=8");
+
+       for (id = 1; id < btf__type_cnt(btf); id++) {
+               struct btf_type *t = btf_type_by_id(btf, id);
+               struct btf_field_iter it_strs, it_ids;
+               int str_idx = 0, id_idx = 0;
+               __u32 *next_str, *next_id;
+
+               if (!ASSERT_OK_PTR(t, "btf_type_by_id"))
+                       break;
+               if (!ASSERT_OK(btf_field_iter_init(&it_strs, t, BTF_FIELD_ITER_STRS),
+                              "iter_init_strs"))
+                       break;
+               if (!ASSERT_OK(btf_field_iter_init(&it_ids, t, BTF_FIELD_ITER_IDS),
+                              "iter_init_ids"))
+                       break;
+               while ((next_str = btf_field_iter_next(&it_strs))) {
+                       const char *str = btf__str_by_offset(btf, *next_str);
+
+                       if (!ASSERT_OK(strcmp(fields[id].strs[str_idx], str), "field_str_match"))
+                               break;
+                       str_idx++;
+               }
+               /* ensure no more strings are expected */
+               ASSERT_EQ(fields[id].strs[str_idx], NULL, "field_str_cnt");
+
+               while ((next_id = btf_field_iter_next(&it_ids))) {
+                       if (!ASSERT_EQ(*next_id, fields[id].ids[id_idx], "field_id_match"))
+                               break;
+                       id_idx++;
+               }
+               /* ensure no more ids are expected */
+               ASSERT_EQ(fields[id].ids[id_idx], 0, "field_id_cnt");
+       }
+       btf__free(btf);
+}