tools/testing/selftests/bpf/prog_tests/link_pinning.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2020 Facebook */
   3
   4 #include <test_progs.h>
   5 #include <sys/stat.h>
   6
   7 #include "test_link_pinning.skel.h"
   8
   9 static int duration = 0;
  10
  11 void test_link_pinning_subtest(struct bpf_program *prog,
  12                                struct test_link_pinning__bss *bss)
  13 {
  14         const char *link_pin_path = "/sys/fs/bpf/pinned_link_test";
  15         struct stat statbuf = {};
  16         struct bpf_link *link;
  17         int err, i;
  18
  19         link = bpf_program__attach(prog);
  20         if (!ASSERT_OK_PTR(link, "link_attach"))
  21                 goto cleanup;
  22
  23         bss->in = 1;
  24         usleep(1);
  25         CHECK(bss->out != 1, "res_check1", "exp %d, got %d\n", 1, bss->out);
  26
  27         /* pin link */
  28         err = bpf_link__pin(link, link_pin_path);
  29         if (CHECK(err, "link_pin", "err: %d\n", err))
  30                 goto cleanup;
  31
  32         CHECK(strcmp(link_pin_path, bpf_link__pin_path(link)), "pin_path1",
  33               "exp %s, got %s\n", link_pin_path, bpf_link__pin_path(link));
  34
  35         /* check that link was pinned */
  36         err = stat(link_pin_path, &statbuf);
  37         if (CHECK(err, "stat_link", "err %d errno %d\n", err, errno))
  38                 goto cleanup;
  39
  40         bss->in = 2;
  41         usleep(1);
  42         CHECK(bss->out != 2, "res_check2", "exp %d, got %d\n", 2, bss->out);
  43
  44         /* destroy link, pinned link should keep program attached */
  45         bpf_link__destroy(link);
  46         link = NULL;
  47
  48         bss->in = 3;
  49         usleep(1);
  50         CHECK(bss->out != 3, "res_check3", "exp %d, got %d\n", 3, bss->out);
  51
  52         /* re-open link from BPFFS */
  53         link = bpf_link__open(link_pin_path);
  54         if (!ASSERT_OK_PTR(link, "link_open"))
  55                 goto cleanup;
  56
  57         CHECK(strcmp(link_pin_path, bpf_link__pin_path(link)), "pin_path2",
  58               "exp %s, got %s\n", link_pin_path, bpf_link__pin_path(link));
  59
  60         /* unpin link from BPFFS, program still attached */
  61         err = bpf_link__unpin(link);
  62         if (CHECK(err, "link_unpin", "err: %d\n", err))
  63                 goto cleanup;
  64
  65         /* still active, as we have FD open now */
  66         bss->in = 4;
  67         usleep(1);
  68         CHECK(bss->out != 4, "res_check4", "exp %d, got %d\n", 4, bss->out);
  69
  70         bpf_link__destroy(link);
  71         link = NULL;
  72
  73         /* Validate it's finally detached.
  74          * Actual detachment might get delayed a bit, so there is no reliable
  75          * way to validate it immediately here, let's count up for long enough
  76          * and see if eventually output stops being updated
  77          */
  78         for (i = 5; i < 10000; i++) {
  79                 bss->in = i;
  80                 usleep(1);
  81                 if (bss->out == i - 1)
  82                         break;
  83         }
  84         CHECK(i == 10000, "link_attached", "got to iteration #%d\n", i);
  85
  86 cleanup:
  87         bpf_link__destroy(link);
  88 }
  89
  90 void test_link_pinning(void)
  91 {
  92         struct test_link_pinning* skel;
  93
  94         skel = test_link_pinning__open_and_load();
  95         if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
  96                 return;
  97
  98         if (test__start_subtest("pin_raw_tp"))
  99                 test_link_pinning_subtest(skel->progs.raw_tp_prog, skel->bss);
 100         if (test__start_subtest("pin_tp_btf"))
 101                 test_link_pinning_subtest(skel->progs.tp_btf_prog, skel->bss);
 102
 103         test_link_pinning__destroy(skel);
 104 }