document riscv64 support in INSTALL document

[android-x86/external-musl-libc.git] / src / time / clock_gettime.c

diff --git a/src/time/clock_gettime.c b/src/time/clock_gettime.c
index ad5c09d..8fd1b8f 100644 (file)
--- a/src/time/clock_gettime.c
+++ b/src/time/clock_gettime.c
@@ -2,32 +2,54 @@
 #include <errno.h>
 #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
+
+static void *volatile vdso_func;
+
+static int cgt_init(clockid_t clk, struct timespec *ts)
 {
-       int r = __syscall(SYS_clock_gettime, clk, ts);
-       if (!r) return r;
+       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;
+
+#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, clk, ts, 0);
+                       __syscall(SYS_gettimeofday, ts, 0);
                        ts->tv_nsec = (int)ts->tv_nsec * 1000;
                        return 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);