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 <stdio.h>
14#ifndef NOLIBC
15#include <sys/auxv.h>
16#include <sys/time.h>
17#endif
18
19#include "kselftest.h"
20#include "parse_vdso.h"
21#include "vdso_config.h"
22#include "vdso_call.h"
23
24int 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}