1#include <time.h> 2#include <errno.h> 3#include <stdint.h> 4#include "syscall.h" 5#include "libc.h" 6#include "atomic.h" 7 8#ifdef VDSO_CGT_SYM 9 10void *__vdsosym(const char *, const char *); 11 12static void *volatile vdso_func; 13 14static int cgt_init(clockid_t clk, struct timespec *ts) 15{ 16 void *p = __vdsosym(VDSO_CGT_VER, VDSO_CGT_SYM); 17 int (*f)(clockid_t, struct timespec *) = 18 (int (*)(clockid_t, struct timespec *))p; 19 a_cas_p(&vdso_func, (void *)cgt_init, p); 20 return f ? f(clk, ts) : -ENOSYS; 21} 22 23static void *volatile vdso_func = (void *)cgt_init; 24 25#endif 26 27int __clock_gettime(clockid_t clk, struct timespec *ts) 28{ 29 int r; 30 31#ifdef VDSO_CGT_SYM 32 int (*f)(clockid_t, struct timespec *) = 33 (int (*)(clockid_t, struct timespec *))vdso_func; 34 if (f) { 35 r = f(clk, ts); 36 if (!r) return r; 37 if (r == -EINVAL) return __syscall_ret(r); 38 /* Fall through on errors other than EINVAL. Some buggy 39 * vdso implementations return ENOSYS for clocks they 40 * can't handle, rather than making the syscall. This 41 * also handles the case where cgt_init fails to find 42 * a vdso function to use. */ 43 } 44#endif 45 46 r = __syscall(SYS_clock_gettime, clk, ts); 47 if (r == -ENOSYS) { 48 if (clk == CLOCK_REALTIME) { 49 __syscall(SYS_gettimeofday, ts, 0); 50 ts->tv_nsec = (int)ts->tv_nsec * 1000; 51 return 0; 52 } 53 r = -EINVAL; 54 } 55 return __syscall_ret(r); 56} 57 58weak_alias(__clock_gettime, clock_gettime); 59