From b72091bd4ee4f4bfdb50468b7465cbc5a7b4442b Mon Sep 17 00:00:00 2001 From: Alan Maguire Date: Mon, 28 Sep 2020 12:31:10 +0100 Subject: selftests/bpf: Add test for bpf_seq_printf_btf helper Add a test verifying iterating over tasks and displaying BTF representation of task_struct succeeds. Suggested-by: Alexei Starovoitov Signed-off-by: Alan Maguire Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/1601292670-1616-9-git-send-email-alan.maguire@oracle.com --- tools/testing/selftests/bpf/prog_tests/bpf_iter.c | 74 ++++++++++++++++++++++ .../selftests/bpf/progs/bpf_iter_task_btf.c | 50 +++++++++++++++ 2 files changed, 124 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_task_btf.c (limited to 'tools') diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c index ad9de136158e..af15630a24dd 100644 --- a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c +++ b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c @@ -7,6 +7,7 @@ #include "bpf_iter_task.skel.h" #include "bpf_iter_task_stack.skel.h" #include "bpf_iter_task_file.skel.h" +#include "bpf_iter_task_btf.skel.h" #include "bpf_iter_tcp4.skel.h" #include "bpf_iter_tcp6.skel.h" #include "bpf_iter_udp4.skel.h" @@ -167,6 +168,77 @@ done: bpf_iter_task_file__destroy(skel); } +#define TASKBUFSZ 32768 + +static char taskbuf[TASKBUFSZ]; + +static void do_btf_read(struct bpf_iter_task_btf *skel) +{ + struct bpf_program *prog = skel->progs.dump_task_struct; + struct bpf_iter_task_btf__bss *bss = skel->bss; + int iter_fd = -1, len = 0, bufleft = TASKBUFSZ; + struct bpf_link *link; + char *buf = taskbuf; + + link = bpf_program__attach_iter(prog, NULL); + if (CHECK(IS_ERR(link), "attach_iter", "attach_iter failed\n")) + return; + + iter_fd = bpf_iter_create(bpf_link__fd(link)); + if (CHECK(iter_fd < 0, "create_iter", "create_iter failed\n")) + goto free_link; + + do { + len = read(iter_fd, buf, bufleft); + if (len > 0) { + buf += len; + bufleft -= len; + } + } while (len > 0); + + if (bss->skip) { + printf("%s:SKIP:no __builtin_btf_type_id\n", __func__); + test__skip(); + goto free_link; + } + + if (CHECK(len < 0, "read", "read failed: %s\n", strerror(errno))) + goto free_link; + + CHECK(strstr(taskbuf, "(struct task_struct)") == NULL, + "check for btf representation of task_struct in iter data", + "struct task_struct not found"); +free_link: + if (iter_fd > 0) + close(iter_fd); + bpf_link__destroy(link); +} + +static void test_task_btf(void) +{ + struct bpf_iter_task_btf__bss *bss; + struct bpf_iter_task_btf *skel; + + skel = bpf_iter_task_btf__open_and_load(); + if (CHECK(!skel, "bpf_iter_task_btf__open_and_load", + "skeleton open_and_load failed\n")) + return; + + bss = skel->bss; + + do_btf_read(skel); + + if (CHECK(bss->tasks == 0, "check if iterated over tasks", + "no task iteration, did BPF program run?\n")) + goto cleanup; + + CHECK(bss->seq_err != 0, "check for unexpected err", + "bpf_seq_printf_btf returned %ld", bss->seq_err); + +cleanup: + bpf_iter_task_btf__destroy(skel); +} + static void test_tcp4(void) { struct bpf_iter_tcp4 *skel; @@ -957,6 +1029,8 @@ void test_bpf_iter(void) test_task_stack(); if (test__start_subtest("task_file")) test_task_file(); + if (test__start_subtest("task_btf")) + test_task_btf(); if (test__start_subtest("tcp4")) test_tcp4(); if (test__start_subtest("tcp6")) diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_task_btf.c b/tools/testing/selftests/bpf/progs/bpf_iter_task_btf.c new file mode 100644 index 000000000000..a1ddc36f13ec --- /dev/null +++ b/tools/testing/selftests/bpf/progs/bpf_iter_task_btf.c @@ -0,0 +1,50 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2020, Oracle and/or its affiliates. */ +#include "bpf_iter.h" +#include +#include +#include + +#include + +char _license[] SEC("license") = "GPL"; + +long tasks = 0; +long seq_err = 0; +bool skip = false; + +SEC("iter/task") +int dump_task_struct(struct bpf_iter__task *ctx) +{ + struct seq_file *seq = ctx->meta->seq; + struct task_struct *task = ctx->task; + static struct btf_ptr ptr = { }; + long ret; + +#if __has_builtin(__builtin_btf_type_id) + ptr.type_id = bpf_core_type_id_kernel(struct task_struct); + ptr.ptr = task; + + if (ctx->meta->seq_num == 0) + BPF_SEQ_PRINTF(seq, "Raw BTF task\n"); + + ret = bpf_seq_printf_btf(seq, &ptr, sizeof(ptr), 0); + switch (ret) { + case 0: + tasks++; + break; + case -ERANGE: + /* NULL task or task->fs, don't count it as an error. */ + break; + case -E2BIG: + return 1; + default: + seq_err = ret; + break; + } +#else + skip = true; +#endif + + return 0; +} -- cgit v1.2.3-58-ga151