From: JP Kobryn <inwardvessel@xxxxxxxxx>
These tests expose the issue of being unable to properly check for errors
returned from bpf helpers that make inline calls to the bpf_map_ops
functions. At best, a check for zero or non-zero can be done but these
tests show it is not possible to check for a negative value or for a
specific error value.
Signed-off-by: JP Kobryn <inwardvessel@xxxxxxxxx>
---
.../selftests/bpf/prog_tests/map_ops.c | 130 ++++++++++++++++++
.../selftests/bpf/progs/test_map_ops.c | 90 ++++++++++++
2 files changed, 220 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/map_ops.c
create mode 100644 tools/testing/selftests/bpf/progs/test_map_ops.c
diff --git a/tools/testing/selftests/bpf/prog_tests/map_ops.c b/tools/testing/selftests/bpf/prog_tests/map_ops.c
new file mode 100644
index 000000000000..d08759801ad2
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/map_ops.c
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
+
+#include <errno.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+#include "test_progs.h"
+#include "test_map_ops.skel.h"
+
+static void map_update(void)
+{
+ (void)syscall(__NR_getpid);
+}
+
+static void map_delete(void)
+{
+ (void)syscall(__NR_getppid);
+}
+
+static void map_push(void)
+{
+ (void)syscall(__NR_getuid);
+}
+
+static void map_pop(void)
+{
+ (void)syscall(__NR_geteuid);
+}
+
+static void map_peek(void)
+{
+ (void)syscall(__NR_getgid);
+}
+
+static int setup(struct test_map_ops **skel)
+{
+ int err = 0;
+
+ if (!skel)
+ return -1;
+
+ *skel = test_map_ops__open();
+ if (!ASSERT_OK_PTR(*skel, "test_map_ops__open"))
+ return -1;
+
+ (*skel)->rodata->pid = getpid();
+
+ err = test_map_ops__load(*skel);
+ if (!ASSERT_OK(err, "test_map_ops__load"))
+ return err;
+
+ err = test_map_ops__attach(*skel);
+ if (!ASSERT_OK(err, "test_map_ops__attach"))
+ return err;
+
+ return err;
+}
+
+static void teardown(struct test_map_ops **skel)
+{
+ if (skel && *skel)
+ test_map_ops__destroy(*skel);
+}
+
+static void map_ops_update_delete_subtest(void)
+{
+ struct test_map_ops *skel;
+
+ if (setup(&skel))
+ goto teardown;
+
+ map_update();
+ ASSERT_OK(skel->bss->err, "map_update_initial");
+
+ map_update();
+ ASSERT_LT(skel->bss->err, 0, "map_update_existing");
+ ASSERT_EQ(skel->bss->err, -EEXIST, "map_update_existing");
+
+ map_delete();
+ ASSERT_OK(skel->bss->err, "map_delete_existing");
+
+ map_delete();
+ ASSERT_LT(skel->bss->err, 0, "map_delete_non_existing");
+ ASSERT_EQ(skel->bss->err, -ENOENT, "map_delete_non_existing");
+
+teardown:
+ teardown(&skel);
+}
+
+static void map_ops_push_peek_pop_subtest(void)
+{
+ struct test_map_ops *skel;
+
+ if (setup(&skel))
+ goto teardown;
+
+ map_push();
+ ASSERT_OK(skel->bss->err, "map_push_initial");
+
+ map_push();
+ ASSERT_LT(skel->bss->err, 0, "map_push_when_full");
+ ASSERT_EQ(skel->bss->err, -E2BIG, "map_push_when_full");
+
+ map_peek();
+ ASSERT_OK(skel->bss->err, "map_peek");
+
+ map_pop();
+ ASSERT_OK(skel->bss->err, "map_pop");
+
+ map_peek();
+ ASSERT_LT(skel->bss->err, 0, "map_peek_when_empty");
+ ASSERT_EQ(skel->bss->err, -ENOENT, "map_peek_when_empty");
+
+ map_pop();
+ ASSERT_LT(skel->bss->err, 0, "map_pop_when_empty");
+ ASSERT_EQ(skel->bss->err, -ENOENT, "map_pop_when_empty");
+
+teardown:
+ teardown(&skel);
+}
+
+void test_map_ops(void)
+{
+ if (test__start_subtest("map_ops_update_delete"))
+ map_ops_update_delete_subtest();
+
+ if (test__start_subtest("map_ops_push_peek_pop"))
+ map_ops_push_peek_pop_subtest();
+}
diff --git a/tools/testing/selftests/bpf/progs/test_map_ops.c b/tools/testing/selftests/bpf/progs/test_map_ops.c
new file mode 100644
index 000000000000..3b684073ea64
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_map_ops.c
@@ -0,0 +1,90 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+
+char _license[] SEC("license") = "GPL";
+
+struct {
+ __uint(type, BPF_MAP_TYPE_HASH);
+ __uint(max_entries, 1);
+ __type(key, int);
+ __type(value, int);
+} hash_map SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_STACK);
+ __uint(max_entries, 1);
+ __type(value, int);
+} stack_map SEC(".maps");
+
+const volatile pid_t pid;
+long err = 0;
+
+SEC("tp/syscalls/sys_enter_getpid")
+int map_update(void *ctx)
+{
+ const int key = 0;
+ const int val = 1;
+
+ if (pid != (bpf_get_current_pid_tgid() >> 32))
+ return 0;
+
+ err = bpf_map_update_elem(&hash_map, &key, &val, BPF_NOEXIST);
+
+ return 0;
+}
+
+SEC("tp/syscalls/sys_enter_getppid")
+int map_delete(void *ctx)
+{
+ const int key = 0;
+
+ if (pid != (bpf_get_current_pid_tgid() >> 32))
+ return 0;
+
+ err = bpf_map_delete_elem(&hash_map, &key);
+
+ return 0;
+}
+
+SEC("tp/syscalls/sys_enter_getuid")
+int map_push(void *ctx)
+{
+ const int val = 1;
+
+ if (pid != (bpf_get_current_pid_tgid() >> 32))
+ return 0;
+
+ err = bpf_map_push_elem(&stack_map, &val, 0);
+
+ return 0;
+}
+
+SEC("tp/syscalls/sys_enter_geteuid")
+int map_pop(void *ctx)
+{
+ int val;
+
+ if (pid != (bpf_get_current_pid_tgid() >> 32))
+ return 0;
+
+ err = bpf_map_pop_elem(&stack_map, &val);
+
+ return 0;
+}
+
+SEC("tp/syscalls/sys_enter_getgid")
+int map_peek(void *ctx)
+{
+ int val;
+
+ if (pid != (bpf_get_current_pid_tgid() >> 32))
+ return 0;
+
+ err = bpf_map_peek_elem(&stack_map, &val);
+
+ return 0;
+}
+
--
2.39.2
