bpf/prog_tests/legacy_printk.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /* Copyright (c) 2021 Facebook */
0003 #include <test_progs.h>
0004 #include "test_legacy_printk.skel.h"
0005
0006 static int execute_one_variant(bool legacy)
0007 {
0008     struct test_legacy_printk *skel;
0009     int err, zero = 0, my_pid = getpid(), res, map_fd;
0010
0011     skel = test_legacy_printk__open();
0012     if (!ASSERT_OK_PTR(skel, "skel_open"))
0013         return -errno;
0014
0015     bpf_program__set_autoload(skel->progs.handle_legacy, legacy);
0016     bpf_program__set_autoload(skel->progs.handle_modern, !legacy);
0017
0018     err = test_legacy_printk__load(skel);
0019     /* no ASSERT_OK, we expect one of two variants can fail here */
0020     if (err)
0021         goto err_out;
0022
0023     if (legacy) {
0024         map_fd = bpf_map__fd(skel->maps.my_pid_map);
0025         err = bpf_map_update_elem(map_fd, &zero, &my_pid, BPF_ANY);
0026         if (!ASSERT_OK(err, "my_pid_map_update"))
0027             goto err_out;
0028         err = bpf_map_lookup_elem(map_fd, &zero, &res);
0029     } else {
0030         skel->bss->my_pid_var = my_pid;
0031     }
0032
0033     err = test_legacy_printk__attach(skel);
0034     if (!ASSERT_OK(err, "skel_attach"))
0035         goto err_out;
0036
0037     usleep(1); /* trigger */
0038
0039     if (legacy) {
0040         map_fd = bpf_map__fd(skel->maps.res_map);
0041         err = bpf_map_lookup_elem(map_fd, &zero, &res);
0042         if (!ASSERT_OK(err, "res_map_lookup"))
0043             goto err_out;
0044     } else {
0045         res = skel->bss->res_var;
0046     }
0047
0048     if (!ASSERT_GT(res, 0, "res")) {
0049         err = -EINVAL;
0050         goto err_out;
0051     }
0052
0053 err_out:
0054     test_legacy_printk__destroy(skel);
0055     return err;
0056 }
0057
0058 void test_legacy_printk(void)
0059 {
0060     /* legacy variant should work everywhere */
0061     ASSERT_OK(execute_one_variant(true /* legacy */), "legacy_case");
0062
0063     /* execute modern variant, can fail the load on old kernels */
0064     execute_one_variant(false);
0065 }