From fe0dd9d4b7402c9773fc7a453fa65875abaa24ec Mon Sep 17 00:00:00 2001 From: Hao Luo Date: Wed, 24 Aug 2022 16:31:14 -0700 Subject: selftests/bpf: Test cgroup_iter. Add a selftest for cgroup_iter. The selftest creates a mini cgroup tree of the following structure: ROOT (working cgroup) | PARENT / \ CHILD1 CHILD2 and tests the following scenarios: - invalid cgroup fd. - pre-order walk over descendants from PARENT. - post-order walk over descendants from PARENT. - walk of ancestors from PARENT. - process only a single object (i.e. PARENT). - early termination. Acked-by: Yonghong Song Acked-by: Andrii Nakryiko Signed-off-by: Hao Luo Link: https://lore.kernel.org/r/20220824233117.1312810-3-haoluo@google.com Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/prog_tests/btf_dump.c | 2 +- .../testing/selftests/bpf/prog_tests/cgroup_iter.c | 224 +++++++++++++++++++++ tools/testing/selftests/bpf/progs/bpf_iter.h | 7 + tools/testing/selftests/bpf/progs/cgroup_iter.c | 39 ++++ 4 files changed, 271 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/cgroup_iter.c create mode 100644 tools/testing/selftests/bpf/progs/cgroup_iter.c diff --git a/tools/testing/selftests/bpf/prog_tests/btf_dump.c b/tools/testing/selftests/bpf/prog_tests/btf_dump.c index 84c1cfaa2b02..a1bae92be1fc 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf_dump.c +++ b/tools/testing/selftests/bpf/prog_tests/btf_dump.c @@ -764,7 +764,7 @@ static void test_btf_dump_struct_data(struct btf *btf, struct btf_dump *d, /* union with nested struct */ TEST_BTF_DUMP_DATA(btf, d, "union", str, union bpf_iter_link_info, BTF_F_COMPACT, - "(union bpf_iter_link_info){.map = (struct){.map_fd = (__u32)1,},.cgroup = (struct){.order = (__u32)1,.cgroup_fd = (__u32)1,},}", + "(union bpf_iter_link_info){.map = (struct){.map_fd = (__u32)1,},.cgroup = (struct){.order = (enum bpf_cgroup_iter_order)BPF_ITER_SELF_ONLY,.cgroup_fd = (__u32)1,},}", { .cgroup = { .order = 1, .cgroup_fd = 1, }}); /* struct skb with nested structs/unions; because type output is so diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_iter.c b/tools/testing/selftests/bpf/prog_tests/cgroup_iter.c new file mode 100644 index 000000000000..38958c37b9ce --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/cgroup_iter.c @@ -0,0 +1,224 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Google */ + +#include +#include +#include +#include "cgroup_iter.skel.h" +#include "cgroup_helpers.h" + +#define ROOT 0 +#define PARENT 1 +#define CHILD1 2 +#define CHILD2 3 +#define NUM_CGROUPS 4 + +#define PROLOGUE "prologue\n" +#define EPILOGUE "epilogue\n" + +static const char *cg_path[] = { + "/", "/parent", "/parent/child1", "/parent/child2" +}; + +static int cg_fd[] = {-1, -1, -1, -1}; +static unsigned long long cg_id[] = {0, 0, 0, 0}; +static char expected_output[64]; + +static int setup_cgroups(void) +{ + int fd, i = 0; + + for (i = 0; i < NUM_CGROUPS; i++) { + fd = create_and_get_cgroup(cg_path[i]); + if (fd < 0) + return fd; + + cg_fd[i] = fd; + cg_id[i] = get_cgroup_id(cg_path[i]); + } + return 0; +} + +static void cleanup_cgroups(void) +{ + int i; + + for (i = 0; i < NUM_CGROUPS; i++) + close(cg_fd[i]); +} + +static void read_from_cgroup_iter(struct bpf_program *prog, int cgroup_fd, + int order, const char *testname) +{ + DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts); + union bpf_iter_link_info linfo; + struct bpf_link *link; + int len, iter_fd; + static char buf[128]; + size_t left; + char *p; + + memset(&linfo, 0, sizeof(linfo)); + linfo.cgroup.cgroup_fd = cgroup_fd; + linfo.cgroup.order = order; + opts.link_info = &linfo; + opts.link_info_len = sizeof(linfo); + + link = bpf_program__attach_iter(prog, &opts); + if (!ASSERT_OK_PTR(link, "attach_iter")) + return; + + iter_fd = bpf_iter_create(bpf_link__fd(link)); + if (iter_fd < 0) + goto free_link; + + memset(buf, 0, sizeof(buf)); + left = ARRAY_SIZE(buf); + p = buf; + while ((len = read(iter_fd, p, left)) > 0) { + p += len; + left -= len; + } + + ASSERT_STREQ(buf, expected_output, testname); + + /* read() after iter finishes should be ok. */ + if (len == 0) + ASSERT_OK(read(iter_fd, buf, sizeof(buf)), "second_read"); + + close(iter_fd); +free_link: + bpf_link__destroy(link); +} + +/* Invalid cgroup. */ +static void test_invalid_cgroup(struct cgroup_iter *skel) +{ + DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts); + union bpf_iter_link_info linfo; + struct bpf_link *link; + + memset(&linfo, 0, sizeof(linfo)); + linfo.cgroup.cgroup_fd = (__u32)-1; + opts.link_info = &linfo; + opts.link_info_len = sizeof(linfo); + + link = bpf_program__attach_iter(skel->progs.cgroup_id_printer, &opts); + ASSERT_ERR_PTR(link, "attach_iter"); + bpf_link__destroy(link); +} + +/* Specifying both cgroup_fd and cgroup_id is invalid. */ +static void test_invalid_cgroup_spec(struct cgroup_iter *skel) +{ + DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts); + union bpf_iter_link_info linfo; + struct bpf_link *link; + + memset(&linfo, 0, sizeof(linfo)); + linfo.cgroup.cgroup_fd = (__u32)cg_fd[PARENT]; + linfo.cgroup.cgroup_id = (__u64)cg_id[PARENT]; + opts.link_info = &linfo; + opts.link_info_len = sizeof(linfo); + + link = bpf_program__attach_iter(skel->progs.cgroup_id_printer, &opts); + ASSERT_ERR_PTR(link, "attach_iter"); + bpf_link__destroy(link); +} + +/* Preorder walk prints parent and child in order. */ +static void test_walk_preorder(struct cgroup_iter *skel) +{ + snprintf(expected_output, sizeof(expected_output), + PROLOGUE "%8llu\n%8llu\n%8llu\n" EPILOGUE, + cg_id[PARENT], cg_id[CHILD1], cg_id[CHILD2]); + + read_from_cgroup_iter(skel->progs.cgroup_id_printer, cg_fd[PARENT], + BPF_ITER_DESCENDANTS_PRE, "preorder"); +} + +/* Postorder walk prints child and parent in order. */ +static void test_walk_postorder(struct cgroup_iter *skel) +{ + snprintf(expected_output, sizeof(expected_output), + PROLOGUE "%8llu\n%8llu\n%8llu\n" EPILOGUE, + cg_id[CHILD1], cg_id[CHILD2], cg_id[PARENT]); + + read_from_cgroup_iter(skel->progs.cgroup_id_printer, cg_fd[PARENT], + BPF_ITER_DESCENDANTS_POST, "postorder"); +} + +/* Walking parents prints parent and then root. */ +static void test_walk_ancestors_up(struct cgroup_iter *skel) +{ + /* terminate the walk when ROOT is met. */ + skel->bss->terminal_cgroup = cg_id[ROOT]; + + snprintf(expected_output, sizeof(expected_output), + PROLOGUE "%8llu\n%8llu\n" EPILOGUE, + cg_id[PARENT], cg_id[ROOT]); + + read_from_cgroup_iter(skel->progs.cgroup_id_printer, cg_fd[PARENT], + BPF_ITER_ANCESTORS_UP, "ancestors_up"); + + skel->bss->terminal_cgroup = 0; +} + +/* Early termination prints parent only. */ +static void test_early_termination(struct cgroup_iter *skel) +{ + /* terminate the walk after the first element is processed. */ + skel->bss->terminate_early = 1; + + snprintf(expected_output, sizeof(expected_output), + PROLOGUE "%8llu\n" EPILOGUE, cg_id[PARENT]); + + read_from_cgroup_iter(skel->progs.cgroup_id_printer, cg_fd[PARENT], + BPF_ITER_DESCENDANTS_PRE, "early_termination"); + + skel->bss->terminate_early = 0; +} + +/* Waling self prints self only. */ +static void test_walk_self_only(struct cgroup_iter *skel) +{ + snprintf(expected_output, sizeof(expected_output), + PROLOGUE "%8llu\n" EPILOGUE, cg_id[PARENT]); + + read_from_cgroup_iter(skel->progs.cgroup_id_printer, cg_fd[PARENT], + BPF_ITER_SELF_ONLY, "self_only"); +} + +void test_cgroup_iter(void) +{ + struct cgroup_iter *skel = NULL; + + if (setup_cgroup_environment()) + return; + + if (setup_cgroups()) + goto out; + + skel = cgroup_iter__open_and_load(); + if (!ASSERT_OK_PTR(skel, "cgroup_iter__open_and_load")) + goto out; + + if (test__start_subtest("cgroup_iter__invalid_cgroup")) + test_invalid_cgroup(skel); + if (test__start_subtest("cgroup_iter__invalid_cgroup_spec")) + test_invalid_cgroup_spec(skel); + if (test__start_subtest("cgroup_iter__preorder")) + test_walk_preorder(skel); + if (test__start_subtest("cgroup_iter__postorder")) + test_walk_postorder(skel); + if (test__start_subtest("cgroup_iter__ancestors_up_walk")) + test_walk_ancestors_up(skel); + if (test__start_subtest("cgroup_iter__early_termination")) + test_early_termination(skel); + if (test__start_subtest("cgroup_iter__self_only")) + test_walk_self_only(skel); +out: + cgroup_iter__destroy(skel); + cleanup_cgroups(); + cleanup_cgroup_environment(); +} diff --git a/tools/testing/selftests/bpf/progs/bpf_iter.h b/tools/testing/selftests/bpf/progs/bpf_iter.h index e9846606690d..c41ee80533ca 100644 --- a/tools/testing/selftests/bpf/progs/bpf_iter.h +++ b/tools/testing/selftests/bpf/progs/bpf_iter.h @@ -17,6 +17,7 @@ #define bpf_iter__bpf_sk_storage_map bpf_iter__bpf_sk_storage_map___not_used #define bpf_iter__sockmap bpf_iter__sockmap___not_used #define bpf_iter__bpf_link bpf_iter__bpf_link___not_used +#define bpf_iter__cgroup bpf_iter__cgroup___not_used #define btf_ptr btf_ptr___not_used #define BTF_F_COMPACT BTF_F_COMPACT___not_used #define BTF_F_NONAME BTF_F_NONAME___not_used @@ -40,6 +41,7 @@ #undef bpf_iter__bpf_sk_storage_map #undef bpf_iter__sockmap #undef bpf_iter__bpf_link +#undef bpf_iter__cgroup #undef btf_ptr #undef BTF_F_COMPACT #undef BTF_F_NONAME @@ -141,6 +143,11 @@ struct bpf_iter__bpf_link { struct bpf_link *link; }; +struct bpf_iter__cgroup { + struct bpf_iter_meta *meta; + struct cgroup *cgroup; +} __attribute__((preserve_access_index)); + struct btf_ptr { void *ptr; __u32 type_id; diff --git a/tools/testing/selftests/bpf/progs/cgroup_iter.c b/tools/testing/selftests/bpf/progs/cgroup_iter.c new file mode 100644 index 000000000000..de03997322a7 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/cgroup_iter.c @@ -0,0 +1,39 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Google */ + +#include "bpf_iter.h" +#include +#include + +char _license[] SEC("license") = "GPL"; +int terminate_early = 0; +u64 terminal_cgroup = 0; + +static inline u64 cgroup_id(struct cgroup *cgrp) +{ + return cgrp->kn->id; +} + +SEC("iter/cgroup") +int cgroup_id_printer(struct bpf_iter__cgroup *ctx) +{ + struct seq_file *seq = ctx->meta->seq; + struct cgroup *cgrp = ctx->cgroup; + + /* epilogue */ + if (cgrp == NULL) { + BPF_SEQ_PRINTF(seq, "epilogue\n"); + return 0; + } + + /* prologue */ + if (ctx->meta->seq_num == 0) + BPF_SEQ_PRINTF(seq, "prologue\n"); + + BPF_SEQ_PRINTF(seq, "%8llu\n", cgroup_id(cgrp)); + + if (terminal_cgroup == cgroup_id(cgrp)) + return 1; + + return terminate_early ? 1 : 0; +} -- cgit v1.2.3-59-g8ed1b