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

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <test_progs.h>
   3 #include "test_probe_read_user_str.skel.h"
   4
   5 static const char str1[] = "mestring";
   6 static const char str2[] = "mestringalittlebigger";
   7 static const char str3[] = "mestringblubblubblubblubblub";
   8
   9 static int test_one_str(struct test_probe_read_user_str *skel, const char *str,
  10                         size_t len)
  11 {
  12         int err, duration = 0;
  13         char buf[256];
  14
  15         /* Ensure bytes after string are ones */
  16         memset(buf, 1, sizeof(buf));
  17         memcpy(buf, str, len);
  18
  19         /* Give prog our userspace pointer */
  20         skel->bss->user_ptr = buf;
  21
  22         /* Trigger tracepoint */
  23         usleep(1);
  24
  25         /* Did helper fail? */
  26         if (CHECK(skel->bss->ret < 0, "prog_ret", "prog returned: %ld\n",
  27                   skel->bss->ret))
  28                 return 1;
  29
  30         /* Check that string was copied correctly */
  31         err = memcmp(skel->bss->buf, str, len);
  32         if (CHECK(err, "memcmp", "prog copied wrong string"))
  33                 return 1;
  34
  35         /* Now check that no extra trailing bytes were copied */
  36         memset(buf, 0, sizeof(buf));
  37         err = memcmp(skel->bss->buf + len, buf, sizeof(buf) - len);
  38         if (CHECK(err, "memcmp", "trailing bytes were not stripped"))
  39                 return 1;
  40
  41         return 0;
  42 }
  43
  44 void test_probe_read_user_str(void)
  45 {
  46         struct test_probe_read_user_str *skel;
  47         int err, duration = 0;
  48
  49         skel = test_probe_read_user_str__open_and_load();
  50         if (CHECK(!skel, "test_probe_read_user_str__open_and_load",
  51                   "skeleton open and load failed\n"))
  52                 return;
  53
  54         /* Give pid to bpf prog so it doesn't read from anyone else */
  55         skel->bss->pid = getpid();
  56
  57         err = test_probe_read_user_str__attach(skel);
  58         if (CHECK(err, "test_probe_read_user_str__attach",
  59                   "skeleton attach failed: %d\n", err))
  60                 goto out;
  61
  62         if (test_one_str(skel, str1, sizeof(str1)))
  63                 goto out;
  64         if (test_one_str(skel, str2, sizeof(str2)))
  65                 goto out;
  66         if (test_one_str(skel, str3, sizeof(str3)))
  67                 goto out;
  68
  69 out:
  70         test_probe_read_user_str__destroy(skel);
  71 }