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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2023 Hengqi Chen */
   3
   4 #include <test_progs.h>
   5 #include "test_uprobe.skel.h"
   6
   7 static FILE *urand_spawn(int *pid)
   8 {
   9         FILE *f;
  10
  11         /* urandom_read's stdout is wired into f */
  12         f = popen("./urandom_read 1 report-pid", "r");
  13         if (!f)
  14                 return NULL;
  15
  16         if (fscanf(f, "%d", pid) != 1) {
  17                 pclose(f);
  18                 errno = EINVAL;
  19                 return NULL;
  20         }
  21
  22         return f;
  23 }
  24
  25 static int urand_trigger(FILE **urand_pipe)
  26 {
  27         int exit_code;
  28
  29         /* pclose() waits for child process to exit and returns their exit code */
  30         exit_code = pclose(*urand_pipe);
  31         *urand_pipe = NULL;
  32
  33         return exit_code;
  34 }
  35
  36 void test_uprobe(void)
  37 {
  38         LIBBPF_OPTS(bpf_uprobe_opts, uprobe_opts);
  39         struct test_uprobe *skel;
  40         FILE *urand_pipe = NULL;
  41         int urand_pid = 0, err;
  42
  43         skel = test_uprobe__open_and_load();
  44         if (!ASSERT_OK_PTR(skel, "skel_open"))
  45                 return;
  46
  47         urand_pipe = urand_spawn(&urand_pid);
  48         if (!ASSERT_OK_PTR(urand_pipe, "urand_spawn"))
  49                 goto cleanup;
  50
  51         skel->bss->my_pid = urand_pid;
  52
  53         /* Manual attach uprobe to urandlib_api
  54          * There are two `urandlib_api` symbols in .dynsym section:
  55          *   - urandlib_api@LIBURANDOM_READ_1.0.0
  56          *   - urandlib_api@@LIBURANDOM_READ_2.0.0
  57          * Both are global bind and would cause a conflict if user
  58          * specify the symbol name without a version suffix
  59          */
  60         uprobe_opts.func_name = "urandlib_api";
  61         skel->links.test4 = bpf_program__attach_uprobe_opts(skel->progs.test4,
  62                                                             urand_pid,
  63                                                             "./liburandom_read.so",
  64                                                             0 /* offset */,
  65                                                             &uprobe_opts);
  66         if (!ASSERT_ERR_PTR(skel->links.test4, "urandlib_api_attach_conflict"))
  67                 goto cleanup;
  68
  69         uprobe_opts.func_name = "urandlib_api@LIBURANDOM_READ_1.0.0";
  70         skel->links.test4 = bpf_program__attach_uprobe_opts(skel->progs.test4,
  71                                                             urand_pid,
  72                                                             "./liburandom_read.so",
  73                                                             0 /* offset */,
  74                                                             &uprobe_opts);
  75         if (!ASSERT_OK_PTR(skel->links.test4, "urandlib_api_attach_ok"))
  76                 goto cleanup;
  77
  78         /* Auto attach 3 u[ret]probes to urandlib_api_sameoffset */
  79         err = test_uprobe__attach(skel);
  80         if (!ASSERT_OK(err, "skel_attach"))
  81                 goto cleanup;
  82
  83         /* trigger urandom_read */
  84         ASSERT_OK(urand_trigger(&urand_pipe), "urand_exit_code");
  85
  86         ASSERT_EQ(skel->bss->test1_result, 1, "urandlib_api_sameoffset");
  87         ASSERT_EQ(skel->bss->test2_result, 1, "urandlib_api_sameoffset@v1");
  88         ASSERT_EQ(skel->bss->test3_result, 3, "urandlib_api_sameoffset@@v2");
  89         ASSERT_EQ(skel->bss->test4_result, 1, "urandlib_api");
  90
  91 cleanup:
  92         if (urand_pipe)
  93                 pclose(urand_pipe);
  94         test_uprobe__destroy(skel);
  95 }