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#include <time.h>
#include <errno.h>
#include <stdint.h>
#include "syscall.h"
#include "atomic.h"
#ifdef VDSO_CGT_SYM
static void *volatile vdso_func;
#ifdef VDSO_CGT32_SYM
static void *volatile vdso_func_32;
static int cgt_time32_wrap(clockid_t clk, struct timespec *ts)
{
long ts32[2];
int (*f)(clockid_t, long[2]) =
(int (*)(clockid_t, long[2]))vdso_func_32;
int r = f(clk, ts32);
if (!r) {
/* Fallback to syscalls if time32 overflowed. Maybe
* we lucked out and somehow migrated to a kernel with
* time64 syscalls available. */
if (ts32[0] < 0) {
a_cas_p(&vdso_func, (void *)cgt_time32_wrap, 0);
return -ENOSYS;
}
ts->tv_sec = ts32[0];
ts->tv_nsec = ts32[1];
}
return r;
}
#endif
static int cgt_init(clockid_t clk, struct timespec *ts)
{
void *p = __vdsosym(VDSO_CGT_VER, VDSO_CGT_SYM);
#ifdef VDSO_CGT32_SYM
if (!p) {
void *q = __vdsosym(VDSO_CGT32_VER, VDSO_CGT32_SYM);
if (q) {
a_cas_p(&vdso_func_32, 0, q);
p = cgt_time32_wrap;
}
}
#endif
int (*f)(clockid_t, struct timespec *) =
(int (*)(clockid_t, struct timespec *))p;
a_cas_p(&vdso_func, (void *)cgt_init, p);
return f ? f(clk, ts) : -ENOSYS;
}
static void *volatile vdso_func = (void *)cgt_init;
#endif
int __clock_gettime(clockid_t clk, struct timespec *ts)
{
int r;
#ifdef VDSO_CGT_SYM
int (*f)(clockid_t, struct timespec *) =
(int (*)(clockid_t, struct timespec *))vdso_func;
if (f) {
r = f(clk, ts);
if (!r) return r;
if (r == -EINVAL) return __syscall_ret(r);
/* Fall through on errors other than EINVAL. Some buggy
* vdso implementations return ENOSYS for clocks they
* can't handle, rather than making the syscall. This
* also handles the case where cgt_init fails to find
* a vdso function to use. */
}
#endif
#ifdef SYS_clock_gettime64
r = -ENOSYS;
if (sizeof(time_t) > 4)
r = __syscall(SYS_clock_gettime64, clk, ts);
if (SYS_clock_gettime == SYS_clock_gettime64 || r!=-ENOSYS)
return __syscall_ret(r);
long ts32[2];
r = __syscall(SYS_clock_gettime, clk, ts32);
if (r==-ENOSYS && clk==CLOCK_REALTIME) {
r = __syscall(SYS_gettimeofday, ts32, 0);
ts32[1] *= 1000;
}
if (!r) {
ts->tv_sec = ts32[0];
ts->tv_nsec = ts32[1];
return r;
}
return __syscall_ret(r);
#else
r = __syscall(SYS_clock_gettime, clk, ts);
if (r == -ENOSYS) {
if (clk == CLOCK_REALTIME) {
__syscall(SYS_gettimeofday, ts, 0);
ts->tv_nsec = (int)ts->tv_nsec * 1000;
return 0;
}
r = -EINVAL;
}
return __syscall_ret(r);
#endif
}
weak_alias(__clock_gettime, clock_gettime);
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