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- /*
- * 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;
- }
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