#include <stdint.h>
#include "syscall.h"
#include "libc.h"
+#include "atomic.h"
-static int sc_clock_gettime(clockid_t clk, struct timespec *ts)
+#ifdef VDSO_CGT_SYM
+
+void *__vdsosym(const char *, const char *);
+
+static void *volatile vdso_func;
+
+static int cgt_init(clockid_t clk, struct timespec *ts)
+{
+ void *p = __vdsosym(VDSO_CGT_VER, VDSO_CGT_SYM);
+ 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 = __syscall(SYS_clock_gettime, clk, ts);
- if (!r) return r;
+ 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
+
+ r = __syscall(SYS_clock_gettime, clk, ts);
if (r == -ENOSYS) {
if (clk == CLOCK_REALTIME) {
__syscall(SYS_gettimeofday, ts, 0);
}
r = -EINVAL;
}
- errno = -r;
- return -1;
-}
-
-weak_alias(sc_clock_gettime, __vdso_clock_gettime);
-
-int (*__cgt)(clockid_t, struct timespec *) = __vdso_clock_gettime;
-
-int __clock_gettime(clockid_t clk, struct timespec *ts)
-{
- /* Conditional is to make this work prior to dynamic linking */
- return __cgt ? __cgt(clk, ts) : sc_clock_gettime(clk, ts);
+ return __syscall_ret(r);
}
weak_alias(__clock_gettime, clock_gettime);