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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2021 Facebook */
   3 #include <test_progs.h>
   4 #include "test_legacy_printk.skel.h"
   5
   6 static int execute_one_variant(bool legacy)
   7 {
   8         struct test_legacy_printk *skel;
   9         int err, zero = 0, my_pid = getpid(), res, map_fd;
  10
  11         skel = test_legacy_printk__open();
  12         if (!ASSERT_OK_PTR(skel, "skel_open"))
  13                 return -errno;
  14
  15         bpf_program__set_autoload(skel->progs.handle_legacy, legacy);
  16         bpf_program__set_autoload(skel->progs.handle_modern, !legacy);
  17
  18         err = test_legacy_printk__load(skel);
  19         /* no ASSERT_OK, we expect one of two variants can fail here */
  20         if (err)
  21                 goto err_out;
  22
  23         if (legacy) {
  24                 map_fd = bpf_map__fd(skel->maps.my_pid_map);
  25                 err = bpf_map_update_elem(map_fd, &zero, &my_pid, BPF_ANY);
  26                 if (!ASSERT_OK(err, "my_pid_map_update"))
  27                         goto err_out;
  28                 err = bpf_map_lookup_elem(map_fd, &zero, &res);
  29         } else {
  30                 skel->bss->my_pid_var = my_pid;
  31         }
  32
  33         err = test_legacy_printk__attach(skel);
  34         if (!ASSERT_OK(err, "skel_attach"))
  35                 goto err_out;
  36
  37         usleep(1); /* trigger */
  38
  39         if (legacy) {
  40                 map_fd = bpf_map__fd(skel->maps.res_map);
  41                 err = bpf_map_lookup_elem(map_fd, &zero, &res);
  42                 if (!ASSERT_OK(err, "res_map_lookup"))
  43                         goto err_out;
  44         } else {
  45                 res = skel->bss->res_var;
  46         }
  47
  48         if (!ASSERT_GT(res, 0, "res")) {
  49                 err = -EINVAL;
  50                 goto err_out;
  51         }
  52
  53 err_out:
  54         test_legacy_printk__destroy(skel);
  55         return err;
  56 }
  57
  58 void test_legacy_printk(void)
  59 {
  60         /* legacy variant should work everywhere */
  61         ASSERT_OK(execute_one_variant(true /* legacy */), "legacy_case");
  62
  63         /* execute modern variant, can fail the load on old kernels */
  64         execute_one_variant(false);
  65 }