Re: [PATCH v2 bpf-next 4/4] selftests/bpf: add dump type data tests to btf dump tests
From: Andrii Nakryiko <hidden>
Date: 2021-01-21 07:06:11
Also in:
bpf, linux-kselftest, lkml
On Sun, Jan 17, 2021 at 2:21 PM Alan Maguire [off-list ref] wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- 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. */ +
[...]