alistair23-linux/tools/testing/selftests/vDSO/vdso_test.c
Shuah Khan f9b6b0ef60 selftests: move vDSO tests from Documentation/vDSO
Remove vDSO from Makefile to move the to selftests. Update vDSO Makefile
to work under selftests. vDSO will not be run as part of selftests suite
and will not be included in install targets. They can be built separately
for now.

Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
2016-09-20 09:58:04 -06:00

53 lines
1.2 KiB
C

/*
* vdso_test.c: Sample code to test parse_vdso.c
* Copyright (c) 2014 Andy Lutomirski
* Subject to the GNU General Public License, version 2
*
* Compile with:
* gcc -std=gnu99 vdso_test.c parse_vdso.c
*
* Tested on x86, 32-bit and 64-bit. It may work on other architectures, too.
*/
#include <stdint.h>
#include <elf.h>
#include <stdio.h>
#include <sys/auxv.h>
#include <sys/time.h>
extern void *vdso_sym(const char *version, const char *name);
extern void vdso_init_from_sysinfo_ehdr(uintptr_t base);
extern void vdso_init_from_auxv(void *auxv);
int main(int argc, char **argv)
{
unsigned long sysinfo_ehdr = getauxval(AT_SYSINFO_EHDR);
if (!sysinfo_ehdr) {
printf("AT_SYSINFO_EHDR is not present!\n");
return 0;
}
vdso_init_from_sysinfo_ehdr(getauxval(AT_SYSINFO_EHDR));
/* Find gettimeofday. */
typedef long (*gtod_t)(struct timeval *tv, struct timezone *tz);
gtod_t gtod = (gtod_t)vdso_sym("LINUX_2.6", "__vdso_gettimeofday");
if (!gtod) {
printf("Could not find __vdso_gettimeofday\n");
return 1;
}
struct timeval tv;
long ret = gtod(&tv, 0);
if (ret == 0) {
printf("The time is %lld.%06lld\n",
(long long)tv.tv_sec, (long long)tv.tv_usec);
} else {
printf("__vdso_gettimeofday failed\n");
}
return 0;
}