On Sun, Jan 17, 2021 at 2:21 PM Alan Maguire <alan.maguire@xxxxxxxxxx> wrote:
>
> Test various type data dumping operations by comparing expected
> format with the dumped string; an snprintf-style printf function
> is used to record the string dumped.
>
> Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
> ---
> tools/testing/selftests/bpf/prog_tests/btf_dump.c | 233 ++++++++++++++++++++++
> 1 file changed, 233 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/btf_dump.c b/tools/testing/selftests/bpf/prog_tests/btf_dump.c
> index c60091e..262561f4 100644
> --- a/tools/testing/selftests/bpf/prog_tests/btf_dump.c
> +++ b/tools/testing/selftests/bpf/prog_tests/btf_dump.c
> @@ -232,6 +232,237 @@ void test_btf_dump_incremental(void)
> btf__free(btf);
> }
>
> +#define STRSIZE 2048
> +#define EXPECTED_STRSIZE 256
> +
> +void btf_dump_snprintf(void *ctx, const char *fmt, va_list args)
> +{
> + char *s = ctx, new[STRSIZE];
> +
> + vsnprintf(new, STRSIZE, fmt, args);
> + strncat(s, new, STRSIZE);
> + vfprintf(ctx, fmt, args);
> +}
> +
> +/* skip "enum "/"struct " prefixes */
> +#define SKIP_PREFIX(_typestr, _prefix) \
> + do { \
> + if (strstr(_typestr, _prefix) == _typestr) \
why not strncmp?
> + _typestr += strlen(_prefix) + 1; \
> + } while (0)
> +
> +int btf_dump_data(struct btf *btf, struct btf_dump *d,
> + char *ptrtype, __u64 flags, void *ptr,
> + char *str, char *expectedval)
> +{
> + struct btf_dump_emit_type_data_opts opts = { 0 };
> + int ret = 0, cmp;
> + __s32 type_id;
> +
> + opts.sz = sizeof(opts);
> + opts.compact = true;
Please use DECLARE_LIBBPF_OPTS(), check other examples in selftests
> + if (flags & BTF_F_NONAME)
> + opts.noname = true;
> + if (flags & BTF_F_ZERO)
> + opts.zero = true;
> + SKIP_PREFIX(ptrtype, "enum");
> + SKIP_PREFIX(ptrtype, "struct");
> + SKIP_PREFIX(ptrtype, "union");
> + type_id = btf__find_by_name(btf, ptrtype);
> + if (CHECK(type_id <= 0, "find type id",
> + "no '%s' in BTF: %d\n", ptrtype, type_id)) {
> + ret = -ENOENT;
> + goto err;
> + }
> + str[0] = '\0';
> + ret = btf_dump__emit_type_data(d, type_id, &opts, ptr);
> + if (CHECK(ret < 0, "btf_dump__emit_type_data",
> + "failed: %d\n", ret))
> + goto err;
> +
> + cmp = strncmp(str, expectedval, EXPECTED_STRSIZE);
> + if (CHECK(cmp, "ensure expected/actual match",
> + "'%s' does not match expected '%s': %d\n",
> + str, expectedval, cmp))
> + ret = -EFAULT;
> +
> +err:
> + if (ret)
> + btf_dump__free(d);
> + return ret;
> +}
> +
> +#define TEST_BTF_DUMP_DATA(_b, _d, _str, _type, _flags, _expected, ...) \
> + do { \
> + char _expectedval[EXPECTED_STRSIZE] = _expected; \
> + char __ptrtype[64] = #_type; \
> + char *_ptrtype = (char *)__ptrtype; \
> + static _type _ptrdata = __VA_ARGS__; \
> + void *_ptr = &_ptrdata; \
> + \
> + if (btf_dump_data(_b, _d, _ptrtype, _flags, _ptr, \
> + _str, _expectedval)) \
> + return; \
> + } while (0)
> +
> +/* Use where expected data string matches its stringified declaration */
> +#define TEST_BTF_DUMP_DATA_C(_b, _d, _str, _type, _opts, ...) \
> + TEST_BTF_DUMP_DATA(_b, _d, _str, _type, _opts, \
> + "(" #_type ")" #__VA_ARGS__, __VA_ARGS__)
> +
> +void test_btf_dump_data(void)
> +{
> + struct btf *btf = libbpf_find_kernel_btf();
> + char str[STRSIZE];
> + struct btf_dump_opts opts = { .ctx = str };
> + struct btf_dump *d;
> +
> + if (CHECK(!btf, "get kernel BTF", "no kernel BTF found"))
> + return;
> +
use libbpf_get_error(), btf won't be NULL on error
> + d = btf_dump__new(btf, NULL, &opts, btf_dump_snprintf);
> +
> + if (CHECK(!d, "new dump", "could not create BTF dump"))
same, d won't be NULL on error
> + return;
> +
> + /* Verify type display for various types. */
> +
[...]
