selftests/bpf: add number iterator tests

Add number iterator (bpf_iter_num_{new,next,destroy}()) tests,
validating the correct handling of various corner and common cases
*at runtime*.

Signed-off-by: Andrii Nakryiko <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alexei Starovoitov <[e-mail]>

tools/testing/selftests/bpf/prog_tests/iters.c

···
 #include "iters.skel.h"
 #include "iters_state_safety.skel.h"
 #include "iters_looping.skel.h"
+#include "iters_num.skel.h"
+
+static void subtest_num_iters(void)
+{
+	struct iters_num *skel;
+	int err;
+
+	skel = iters_num__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "skel_open_and_load"))
+		return;
+
+	err = iters_num__attach(skel);
+	if (!ASSERT_OK(err, "skel_attach"))
+		goto cleanup;
+
+	usleep(1);
+	iters_num__detach(skel);
+
+#define VALIDATE_CASE(case_name)					\
+	ASSERT_EQ(skel->bss->res_##case_name,				\
+		  skel->rodata->exp_##case_name,			\
+		  #case_name)
+
+	VALIDATE_CASE(empty_zero);
+	VALIDATE_CASE(empty_int_min);
+	VALIDATE_CASE(empty_int_max);
+	VALIDATE_CASE(empty_minus_one);
+
+	VALIDATE_CASE(simple_sum);
+	VALIDATE_CASE(neg_sum);
+	VALIDATE_CASE(very_neg_sum);
+	VALIDATE_CASE(neg_pos_sum);
+
+	VALIDATE_CASE(invalid_range);
+	VALIDATE_CASE(max_range);
+	VALIDATE_CASE(e2big_range);
+
+	VALIDATE_CASE(succ_elem_cnt);
+	VALIDATE_CASE(overfetched_elem_cnt);
+	VALIDATE_CASE(fail_elem_cnt);
+
+#undef VALIDATE_CASE
+
+cleanup:
+	iters_num__destroy(skel);
+}
 
 void test_iters(void)
 {
 	RUN_TESTS(iters_state_safety);
 	RUN_TESTS(iters_looping);
 	RUN_TESTS(iters);
+
+	if (test__start_subtest("num"))
+		subtest_num_iters();
 }

tools/testing/selftests/bpf/progs/iters_num.c

···
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
+
+#include <limits.h>
+#include <linux/errno.h>
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+
+const volatile __s64 exp_empty_zero = 0 + 1;
+__s64 res_empty_zero;
+
+SEC("raw_tp/sys_enter")
+int num_empty_zero(const void *ctx)
+{
+	__s64 sum = 0, i;
+
+	bpf_for(i, 0, 0) sum += i;
+	res_empty_zero = 1 + sum;
+
+	return 0;
+}
+
+const volatile __s64 exp_empty_int_min = 0 + 2;
+__s64 res_empty_int_min;
+
+SEC("raw_tp/sys_enter")
+int num_empty_int_min(const void *ctx)
+{
+	__s64 sum = 0, i;
+
+	bpf_for(i, INT_MIN, INT_MIN) sum += i;
+	res_empty_int_min = 2 + sum;
+
+	return 0;
+}
+
+const volatile __s64 exp_empty_int_max = 0 + 3;
+__s64 res_empty_int_max;
+
+SEC("raw_tp/sys_enter")
+int num_empty_int_max(const void *ctx)
+{
+	__s64 sum = 0, i;
+
+	bpf_for(i, INT_MAX, INT_MAX) sum += i;
+	res_empty_int_max = 3 + sum;
+
+	return 0;
+}
+
+const volatile __s64 exp_empty_minus_one = 0 + 4;
+__s64 res_empty_minus_one;
+
+SEC("raw_tp/sys_enter")
+int num_empty_minus_one(const void *ctx)
+{
+	__s64 sum = 0, i;
+
+	bpf_for(i, -1, -1) sum += i;
+	res_empty_minus_one = 4 + sum;
+
+	return 0;
+}
+
+const volatile __s64 exp_simple_sum = 9 * 10 / 2;
+__s64 res_simple_sum;
+
+SEC("raw_tp/sys_enter")
+int num_simple_sum(const void *ctx)
+{
+	__s64 sum = 0, i;
+
+	bpf_for(i, 0, 10) sum += i;
+	res_simple_sum = sum;
+
+	return 0;
+}
+
+const volatile __s64 exp_neg_sum = -11 * 10 / 2;
+__s64 res_neg_sum;
+
+SEC("raw_tp/sys_enter")
+int num_neg_sum(const void *ctx)
+{
+	__s64 sum = 0, i;
+
+	bpf_for(i, -10, 0) sum += i;
+	res_neg_sum = sum;
+
+	return 0;
+}
+
+const volatile __s64 exp_very_neg_sum = INT_MIN + (__s64)(INT_MIN + 1);
+__s64 res_very_neg_sum;
+
+SEC("raw_tp/sys_enter")
+int num_very_neg_sum(const void *ctx)
+{
+	__s64 sum = 0, i;
+
+	bpf_for(i, INT_MIN, INT_MIN + 2) sum += i;
+	res_very_neg_sum = sum;
+
+	return 0;
+}
+
+const volatile __s64 exp_very_big_sum = (__s64)(INT_MAX - 1) + (__s64)(INT_MAX - 2);
+__s64 res_very_big_sum;
+
+SEC("raw_tp/sys_enter")
+int num_very_big_sum(const void *ctx)
+{
+	__s64 sum = 0, i;
+
+	bpf_for(i, INT_MAX - 2, INT_MAX) sum += i;
+	res_very_big_sum = sum;
+
+	return 0;
+}
+
+const volatile __s64 exp_neg_pos_sum = -3;
+__s64 res_neg_pos_sum;
+
+SEC("raw_tp/sys_enter")
+int num_neg_pos_sum(const void *ctx)
+{
+	__s64 sum = 0, i;
+
+	bpf_for(i, -3, 3) sum += i;
+	res_neg_pos_sum = sum;
+
+	return 0;
+}
+
+const volatile __s64 exp_invalid_range = -EINVAL;
+__s64 res_invalid_range;
+
+SEC("raw_tp/sys_enter")
+int num_invalid_range(const void *ctx)
+{
+	struct bpf_iter_num it;
+
+	res_invalid_range = bpf_iter_num_new(&it, 1, 0);
+	bpf_iter_num_destroy(&it);
+
+	return 0;
+}
+
+const volatile __s64 exp_max_range = 0 + 10;
+__s64 res_max_range;
+
+SEC("raw_tp/sys_enter")
+int num_max_range(const void *ctx)
+{
+	struct bpf_iter_num it;
+
+	res_max_range = 10 + bpf_iter_num_new(&it, 0, BPF_MAX_LOOPS);
+	bpf_iter_num_destroy(&it);
+
+	return 0;
+}
+
+const volatile __s64 exp_e2big_range = -E2BIG;
+__s64 res_e2big_range;
+
+SEC("raw_tp/sys_enter")
+int num_e2big_range(const void *ctx)
+{
+	struct bpf_iter_num it;
+
+	res_e2big_range = bpf_iter_num_new(&it, -1, BPF_MAX_LOOPS);
+	bpf_iter_num_destroy(&it);
+
+	return 0;
+}
+
+const volatile __s64 exp_succ_elem_cnt = 10;
+__s64 res_succ_elem_cnt;
+
+SEC("raw_tp/sys_enter")
+int num_succ_elem_cnt(const void *ctx)
+{
+	struct bpf_iter_num it;
+	int cnt = 0, *v;
+
+	bpf_iter_num_new(&it, 0, 10);
+	while ((v = bpf_iter_num_next(&it))) {
+		cnt++;
+	}
+	bpf_iter_num_destroy(&it);
+
+	res_succ_elem_cnt = cnt;
+
+	return 0;
+}
+
+const volatile __s64 exp_overfetched_elem_cnt = 5;
+__s64 res_overfetched_elem_cnt;
+
+SEC("raw_tp/sys_enter")
+int num_overfetched_elem_cnt(const void *ctx)
+{
+	struct bpf_iter_num it;
+	int cnt = 0, *v, i;
+
+	bpf_iter_num_new(&it, 0, 5);
+	for (i = 0; i < 10; i++) {
+		v = bpf_iter_num_next(&it);
+		if (v)
+			cnt++;
+	}
+	bpf_iter_num_destroy(&it);
+
+	res_overfetched_elem_cnt = cnt;
+
+	return 0;
+}
+
+const volatile __s64 exp_fail_elem_cnt = 20 + 0;
+__s64 res_fail_elem_cnt;
+
+SEC("raw_tp/sys_enter")
+int num_fail_elem_cnt(const void *ctx)
+{
+	struct bpf_iter_num it;
+	int cnt = 0, *v, i;
+
+	bpf_iter_num_new(&it, 100, 10);
+	for (i = 0; i < 10; i++) {
+		v = bpf_iter_num_next(&it);
+		if (v)
+			cnt++;
+	}
+	bpf_iter_num_destroy(&it);
+
+	res_fail_elem_cnt = 20 + cnt;
+
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";