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 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