4ebbefd6b9
This adds a new vdso_test.c that's written entirely in C. It also makes all of the vDSO examples work on 32-bit x86. Cc: Stefani Seibold <stefani@seibold.net> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/62b701fc44b79f118ac2b2d64d19965fc5c291fb.1402620737.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@zytor.com>
52 lines
1.2 KiB
C
52 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;
|
|
}
|