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
22 /*
23 * ARM64's vDSO exports its gettimeofday() implementation with a different
24 * name and version from other architectures, so we need to handle it as
25 * a special case.
26 */
27 #if defined(__aarch64__)
28 const char *version = "LINUX_2.6.39";
29 const char *name = "__kernel_gettimeofday";
30 #else
31 const char *version = "LINUX_2.6";
32 const char *name = "__vdso_gettimeofday";
33 #endif
34
main(int argc,char ** argv)35 int main(int argc, char **argv)
36 {
37 unsigned long sysinfo_ehdr = getauxval(AT_SYSINFO_EHDR);
38 if (!sysinfo_ehdr) {
39 printf("AT_SYSINFO_EHDR is not present!\n");
40 return KSFT_SKIP;
41 }
42
43 vdso_init_from_sysinfo_ehdr(getauxval(AT_SYSINFO_EHDR));
44
45 /* Find gettimeofday. */
46 typedef long (*gtod_t)(struct timeval *tv, struct timezone *tz);
47 gtod_t gtod = (gtod_t)vdso_sym(version, name);
48
49 if (!gtod) {
50 printf("Could not find %s\n", name);
51 return KSFT_SKIP;
52 }
53
54 struct timeval tv;
55 long ret = gtod(&tv, 0);
56
57 if (ret == 0) {
58 printf("The time is %lld.%06lld\n",
59 (long long)tv.tv_sec, (long long)tv.tv_usec);
60 } else {
61 printf("%s failed\n", name);
62 return KSFT_FAIL;
63 }
64
65 return 0;
66 }
67