On 6/28/19 8:49 PM, Andrii Nakryiko wrote:
> Add tests verifying kprobe/kretprobe/uprobe/uretprobe APIs work as
> expected.
>
> Signed-off-by: Andrii Nakryiko <andriin@xxxxxx>
> Reviewed-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
> Acked-by: Song Liu <songliubraving@xxxxxx>
> ---
> .../selftests/bpf/prog_tests/attach_probe.c | 155 ++++++++++++++++++
> .../selftests/bpf/progs/test_attach_probe.c | 55 +++++++
> 2 files changed, 210 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/prog_tests/attach_probe.c
> create mode 100644 tools/testing/selftests/bpf/progs/test_attach_probe.c
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/attach_probe.c b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
> new file mode 100644
> index 000000000000..f22929063c58
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
> @@ -0,0 +1,155 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <test_progs.h>
> +
> +ssize_t get_base_addr() {
> + size_t start;
> + char buf[256];
> + FILE *f;
> +
> + f = fopen("/proc/self/maps", "r");
> + if (!f)
> + return -errno;
> +
> + while (fscanf(f, "%zx-%*x %s %*s\n", &start, buf) == 2) {
> + if (strcmp(buf, "r-xp") == 0) {
> + fclose(f);
> + return start;
> + }
> + }
> +
> + fclose(f);
> + return -EINVAL;
> +}
> +
> +void test_attach_probe(void)
> +{
> + const char *kprobe_name = "kprobe/sys_nanosleep";
> + const char *kretprobe_name = "kretprobe/sys_nanosleep";
> + const char *uprobe_name = "uprobe/trigger_func";
> + const char *uretprobe_name = "uretprobe/trigger_func";
> + const int kprobe_idx = 0, kretprobe_idx = 1;
> + const int uprobe_idx = 2, uretprobe_idx = 3;
> + const char *file = "./test_attach_probe.o";
> + struct bpf_program *kprobe_prog, *kretprobe_prog;
> + struct bpf_program *uprobe_prog, *uretprobe_prog;
> + struct bpf_object *obj;
> + int err, prog_fd, duration = 0, res;
> + struct bpf_link *kprobe_link = NULL;
> + struct bpf_link *kretprobe_link = NULL;
> + struct bpf_link *uprobe_link = NULL;
> + struct bpf_link *uretprobe_link = NULL;
> + int results_map_fd;
> + size_t uprobe_offset;
> + ssize_t base_addr;
> +
> + base_addr = get_base_addr();
> + if (CHECK(base_addr < 0, "get_base_addr",
> + "failed to find base addr: %zd", base_addr))
> + return;
> + uprobe_offset = (size_t)&get_base_addr - base_addr;
> +
> + /* load programs */
> + err = bpf_prog_load(file, BPF_PROG_TYPE_KPROBE, &obj, &prog_fd);
> + if (CHECK(err, "obj_load", "err %d errno %d\n", err, errno))
> + return;
> +
> + kprobe_prog = bpf_object__find_program_by_title(obj, kprobe_name);
> + if (CHECK(!kprobe_prog, "find_probe",
> + "prog '%s' not found\n", kprobe_name))
> + goto cleanup;
> + kretprobe_prog = bpf_object__find_program_by_title(obj, kretprobe_name);
> + if (CHECK(!kretprobe_prog, "find_probe",
> + "prog '%s' not found\n", kretprobe_name))
> + goto cleanup;
> + uprobe_prog = bpf_object__find_program_by_title(obj, uprobe_name);
> + if (CHECK(!uprobe_prog, "find_probe",
> + "prog '%s' not found\n", uprobe_name))
> + goto cleanup;
> + uretprobe_prog = bpf_object__find_program_by_title(obj, uretprobe_name);
> + if (CHECK(!uretprobe_prog, "find_probe",
> + "prog '%s' not found\n", uretprobe_name))
> + goto cleanup;
> +
> + /* load maps */
> + results_map_fd = bpf_find_map(__func__, obj, "results_map");
> + if (CHECK(results_map_fd < 0, "find_results_map",
> + "err %d\n", results_map_fd))
> + goto cleanup;
> +
> + kprobe_link = bpf_program__attach_kprobe(kprobe_prog,
> + false /* retprobe */,
> + "sys_nanosleep");
Another thing, in current kernel, `sys_nanosleep`does not exist
on x64. It is `__x64_sys_nanosleep`. See samples/bpf/bpf_load.c
function load_and_attach(). You can use macros to differentiate
different architectures.
> + if (CHECK(IS_ERR(kprobe_link), "attach_kprobe",
> + "err %ld\n", PTR_ERR(kprobe_link)))
> + goto cleanup;
> +
> + kretprobe_link = bpf_program__attach_kprobe(kretprobe_prog,
> + true /* retprobe */,
> + "sys_nanosleep");
> + if (CHECK(IS_ERR(kretprobe_link), "attach_kretprobe",
> + "err %ld\n", PTR_ERR(kretprobe_link)))
> + goto cleanup;
> +
> + uprobe_link = bpf_program__attach_uprobe(uprobe_prog,
> + false /* retprobe */,
> + 0 /* self pid */,
> + "/proc/self/exe",
> + uprobe_offset);
> + if (CHECK(IS_ERR(uprobe_link), "attach_uprobe",
> + "err %ld\n", PTR_ERR(uprobe_link)))
> + goto cleanup;
> +
> + uretprobe_link = bpf_program__attach_uprobe(uretprobe_prog,
> + true /* retprobe */,
> + -1 /* any pid */,
> + "/proc/self/exe",
> + uprobe_offset);
> + if (CHECK(IS_ERR(uretprobe_link), "attach_uretprobe",
> + "err %ld\n", PTR_ERR(uretprobe_link)))
> + goto cleanup;
> +
> + /* trigger & validate kprobe && kretprobe */
> + usleep(1);
> +
> + err = bpf_map_lookup_elem(results_map_fd, &kprobe_idx, &res);
> + if (CHECK(err, "get_kprobe_res",
> + "failed to get kprobe res: %d\n", err))
> + goto cleanup;
> + if (CHECK(res != kprobe_idx + 1, "check_kprobe_res",
> + "wrong kprobe res: %d\n", res))
> + goto cleanup;
> +
> + err = bpf_map_lookup_elem(results_map_fd, &kretprobe_idx, &res);
> + if (CHECK(err, "get_kretprobe_res",
> + "failed to get kretprobe res: %d\n", err))
> + goto cleanup;
> + if (CHECK(res != kretprobe_idx + 1, "check_kretprobe_res",
> + "wrong kretprobe res: %d\n", res))
> + goto cleanup;
> +
> + /* trigger & validate uprobe & uretprobe */
> + get_base_addr();
> +
> + err = bpf_map_lookup_elem(results_map_fd, &uprobe_idx, &res);
> + if (CHECK(err, "get_uprobe_res",
> + "failed to get uprobe res: %d\n", err))
> + goto cleanup;
> + if (CHECK(res != uprobe_idx + 1, "check_uprobe_res",
> + "wrong uprobe res: %d\n", res))
> + goto cleanup;
> +
> + err = bpf_map_lookup_elem(results_map_fd, &uretprobe_idx, &res);
> + if (CHECK(err, "get_uretprobe_res",
> + "failed to get uretprobe res: %d\n", err))
> + goto cleanup;
> + if (CHECK(res != uretprobe_idx + 1, "check_uretprobe_res",
> + "wrong uretprobe res: %d\n", res))
> + goto cleanup;
> +
> +cleanup:
> + bpf_link__destroy(kprobe_link);
> + bpf_link__destroy(kretprobe_link);
> + bpf_link__destroy(uprobe_link);
> + bpf_link__destroy(uretprobe_link);
> + bpf_object__close(obj);
> +}
[...]
