From df36e621418b0de4d4afec5f8002d45ee636bb5c Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 7 Aug 2019 14:39:53 -0700 Subject: [PATCH] selftests/bpf: add CO-RE relocs testing setup Add CO-RE relocation test runner. Add one simple test validating that libbpf's logic for searching for kernel image and loading BTF out of it works. Signed-off-by: Andrii Nakryiko Acked-by: Song Liu Signed-off-by: Alexei Starovoitov --- .../testing/selftests/bpf/prog_tests/core_reloc.c | 129 +++++++++++++++++++++ .../selftests/bpf/progs/test_core_reloc_kernel.c | 36 ++++++ 2 files changed, 165 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/core_reloc.c create mode 100644 tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c diff --git a/tools/testing/selftests/bpf/prog_tests/core_reloc.c b/tools/testing/selftests/bpf/prog_tests/core_reloc.c new file mode 100644 index 0000000..4323a45 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/core_reloc.c @@ -0,0 +1,129 @@ +// SPDX-License-Identifier: GPL-2.0 +#include + +struct core_reloc_test_case { + const char *case_name; + const char *bpf_obj_file; + const char *btf_src_file; + const char *input; + int input_len; + const char *output; + int output_len; + bool fails; +}; + +static struct core_reloc_test_case test_cases[] = { + /* validate we can find kernel image and use its BTF for relocs */ + { + .case_name = "kernel", + .bpf_obj_file = "test_core_reloc_kernel.o", + .btf_src_file = NULL, /* load from /lib/modules/$(uname -r) */ + .input = "", + .input_len = 0, + .output = "\1", /* true */ + .output_len = 1, + }, +}; + +struct data { + char in[256]; + char out[256]; +}; + +void test_core_reloc(void) +{ + const char *probe_name = "raw_tracepoint/sys_enter"; + struct bpf_object_load_attr load_attr = {}; + struct core_reloc_test_case *test_case; + int err, duration = 0, i, equal; + struct bpf_link *link = NULL; + struct bpf_map *data_map; + struct bpf_program *prog; + struct bpf_object *obj; + const int zero = 0; + struct data data; + + for (i = 0; i < ARRAY_SIZE(test_cases); i++) { + test_case = &test_cases[i]; + + if (!test__start_subtest(test_case->case_name)) + continue; + + obj = bpf_object__open(test_case->bpf_obj_file); + if (CHECK(IS_ERR_OR_NULL(obj), "obj_open", + "failed to open '%s': %ld\n", + test_case->bpf_obj_file, PTR_ERR(obj))) + continue; + + prog = bpf_object__find_program_by_title(obj, probe_name); + if (CHECK(!prog, "find_probe", + "prog '%s' not found\n", probe_name)) + goto cleanup; + bpf_program__set_type(prog, BPF_PROG_TYPE_RAW_TRACEPOINT); + + load_attr.obj = obj; + load_attr.log_level = 0; + load_attr.target_btf_path = test_case->btf_src_file; + err = bpf_object__load_xattr(&load_attr); + if (test_case->fails) { + CHECK(!err, "obj_load_fail", + "should fail to load prog '%s'\n", probe_name); + goto cleanup; + } else { + if (CHECK(err, "obj_load", + "failed to load prog '%s': %d\n", + probe_name, err)) + goto cleanup; + } + + link = bpf_program__attach_raw_tracepoint(prog, "sys_enter"); + if (CHECK(IS_ERR(link), "attach_raw_tp", "err %ld\n", + PTR_ERR(link))) + goto cleanup; + + data_map = bpf_object__find_map_by_name(obj, "test_cor.bss"); + if (CHECK(!data_map, "find_data_map", "data map not found\n")) + goto cleanup; + + memset(&data, 0, sizeof(data)); + memcpy(data.in, test_case->input, test_case->input_len); + + err = bpf_map_update_elem(bpf_map__fd(data_map), + &zero, &data, 0); + if (CHECK(err, "update_data_map", + "failed to update .data map: %d\n", err)) + goto cleanup; + + /* trigger test run */ + usleep(1); + + err = bpf_map_lookup_elem(bpf_map__fd(data_map), &zero, &data); + if (CHECK(err, "get_result", + "failed to get output data: %d\n", err)) + goto cleanup; + + equal = memcmp(data.out, test_case->output, + test_case->output_len) == 0; + if (CHECK(!equal, "check_result", + "input/output data don't match\n")) { + int j; + + for (j = 0; j < test_case->input_len; j++) { + printf("input byte #%d: 0x%02hhx\n", + j, test_case->input[j]); + } + for (j = 0; j < test_case->output_len; j++) { + printf("output byte #%d: EXP 0x%02hhx GOT 0x%02hhx\n", + j, test_case->output[j], data.out[j]); + } + goto cleanup; + } + +cleanup: + if (!IS_ERR_OR_NULL(link)) { + bpf_link__destroy(link); + link = NULL; + } + bpf_object__close(obj); + } +} diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c b/tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c new file mode 100644 index 0000000..37e02aa --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c @@ -0,0 +1,36 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2019 Facebook + +#include +#include +#include "bpf_helpers.h" + +char _license[] SEC("license") = "GPL"; + +static volatile struct data { + char in[256]; + char out[256]; +} data; + +struct task_struct { + int pid; + int tgid; +}; + +SEC("raw_tracepoint/sys_enter") +int test_core_kernel(void *ctx) +{ + struct task_struct *task = (void *)bpf_get_current_task(); + uint64_t pid_tgid = bpf_get_current_pid_tgid(); + int pid, tgid; + + if (BPF_CORE_READ(&pid, &task->pid) || + BPF_CORE_READ(&tgid, &task->tgid)) + return 1; + + /* validate pid + tgid matches */ + data.out[0] = (((uint64_t)pid << 32) | tgid) == pid_tgid; + + return 0; +} + -- 2.7.4