tools/testing/selftests/vDSO/vdso_test_gettimeofday.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * vdso_test_gettimeofday.c: Sample code to test parse_vdso.c and
   4  *                           vDSO gettimeofday()
   5  * Copyright (c) 2014 Andy Lutomirski
   6  *
   7  * Compile with:
   8  * gcc -std=gnu99 vdso_test_gettimeofday.c parse_vdso_gettimeofday.c
   9  *
  10  * Tested on x86, 32-bit and 64-bit.  It may work on other architectures, too.
  11  */
  12
  13 #include <stdint.h>
  14 #include <elf.h>
  15 #include <stdio.h>
  16 #include <sys/auxv.h>
  17 #include <sys/time.h>
  18
  19 #include "../kselftest.h"
  20 #include "parse_vdso.h"
  21 #include "vdso_config.h"
  22 #include "vdso_call.h"
  23
  24 int main(int argc, char **argv)
  25 {
  26         const char *version = versions[VDSO_VERSION];
  27         const char **name = (const char **)&names[VDSO_NAMES];
  28
  29         unsigned long sysinfo_ehdr = getauxval(AT_SYSINFO_EHDR);
  30         if (!sysinfo_ehdr) {
  31                 printf("AT_SYSINFO_EHDR is not present!\n");
  32                 return KSFT_SKIP;
  33         }
  34
  35         vdso_init_from_sysinfo_ehdr(getauxval(AT_SYSINFO_EHDR));
  36
  37         /* Find gettimeofday. */
  38         typedef long (*gtod_t)(struct timeval *tv, struct timezone *tz);
  39         gtod_t gtod = (gtod_t)vdso_sym(version, name[0]);
  40
  41         if (!gtod) {
  42                 printf("Could not find %s\n", name[0]);
  43                 return KSFT_SKIP;
  44         }
  45
  46         struct timeval tv;
  47         long ret = VDSO_CALL(gtod, 2, &tv, 0);
  48
  49         if (ret == 0) {
  50                 printf("The time is %lld.%06lld\n",
  51                        (long long)tv.tv_sec, (long long)tv.tv_usec);
  52         } else {
  53                 printf("%s failed\n", name[0]);
  54                 return KSFT_FAIL;
  55         }
  56
  57         return 0;
  58 }