[RFC PATCH 07/52] Y2038: add function __clock_gettime64

["Albert ARIBAUD (3ADEV)" <albert.aribaud@3adev.fr>]

Note: __clock_gettime64 is implemented in VDSO.
Signed-off-by: Albert ARIBAUD (3ADEV) <albert.aribaud@3adev.fr>
---
 include/time.h                           |  8 ++++++
 sysdeps/unix/clock_gettime.c             | 46 ++++++++++++++++++++++++++++++++
 sysdeps/unix/sysv/linux/arm/Versions     |  3 +++
 sysdeps/unix/sysv/linux/arm/init-first.c | 15 +++++++++++
 sysdeps/unix/sysv/linux/arm/libc-vdso.h  |  1 +
 sysdeps/unix/sysv/linux/clock_gettime.c  | 44 ++++++++++++++++++++++++++++++
 6 files changed, 117 insertions(+)

diff --git a/include/time.h b/include/time.h
index c436c44539..eeefbb4e98 100644
--- a/include/time.h
+++ b/include/time.h
@@ -20,6 +20,11 @@ libc_hidden_proto (localtime)
 libc_hidden_proto (strftime)
 libc_hidden_proto (strptime)
 
+/* Indicates whether the underlying kernel has 64-bit time support.
+   This is required for e.g. librt, which cannot directly check the
+   flag variable that init-first.c sets when detecting support. */
+extern int __y2038_kernel_support (void);
+
 #if BYTE_ORDER == BIG_ENDIAN
 struct __timespec64
 {
@@ -43,6 +48,9 @@ extern __typeof (clock_settime) __clock_settime;
 extern __typeof (clock_nanosleep) __clock_nanosleep;
 extern __typeof (clock_getcpuclockid) __clock_getcpuclockid;
 
+extern int __clock_gettime64 (clockid_t __clock_id,
+			      struct __timespec64 *__tp) __THROW;
+
 /* Now define the internal interfaces.  */
 struct tm;
 
diff --git a/sysdeps/unix/clock_gettime.c b/sysdeps/unix/clock_gettime.c
index 5262066f51..ac224c919b 100644
--- a/sysdeps/unix/clock_gettime.c
+++ b/sysdeps/unix/clock_gettime.c
@@ -134,3 +134,49 @@ __clock_gettime (clockid_t clock_id, struct timespec *tp)
 }
 weak_alias (__clock_gettime, clock_gettime)
 libc_hidden_def (__clock_gettime)
+
+/* Get current value of CLOCK and store it in TP, 64-bit version.  */
+int
+__clock_gettime64 (clockid_t clock_id, struct __timespec64 *tp)
+{
+  int retval = -1;
+
+  switch (clock_id)
+    {
+#ifdef SYSDEP_GETTIME64
+      SYSDEP_GETTIME64;
+#endif
+
+#ifndef HANDLED_REALTIME
+    case CLOCK_REALTIME:
+      {
+	struct timeval tv;
+	retval = gettimeofday (&tv, NULL);
+	if (retval == 0)
+	  TIMEVAL_TO_TIMESPEC (&tv, tp);
+      }
+      break;
+#endif
+
+    default:
+#ifdef SYSDEP_GETTIME64_CPU
+      SYSDEP_GETTIME64_CPU (clock_id, tp);
+#endif
+#if HP_TIMING_AVAIL
+      if ((clock_id & ((1 << CLOCK_IDFIELD_SIZE) - 1))
+	  == CLOCK_THREAD_CPUTIME_ID)
+	retval = hp_timing_gettime (clock_id, tp);
+      else
+#endif
+	__set_errno (EINVAL);
+      break;
+
+#if HP_TIMING_AVAIL && !defined HANDLED_CPUTIME
+    case CLOCK_PROCESS_CPUTIME_ID:
+      retval = hp_timing_gettime (clock_id, tp);
+      break;
+#endif
+    }
+
+  return retval;
+}
diff --git a/sysdeps/unix/sysv/linux/arm/Versions b/sysdeps/unix/sysv/linux/arm/Versions
index f7feda3650..a2655d6262 100644
--- a/sysdeps/unix/sysv/linux/arm/Versions
+++ b/sysdeps/unix/sysv/linux/arm/Versions
@@ -27,5 +27,8 @@ libc {
     __localtime64; __localtime64_r;
     __mktime64; __timelocal64_r;
     __timegm64;
+    __clock_gettime64;
+    __vdso_clock_gettime64;
+    __y2038_kernel_support;
   }
 }
diff --git a/sysdeps/unix/sysv/linux/arm/init-first.c b/sysdeps/unix/sysv/linux/arm/init-first.c
index 3c289c2a25..61c01a56a7 100644
--- a/sysdeps/unix/sysv/linux/arm/init-first.c
+++ b/sysdeps/unix/sysv/linux/arm/init-first.c
@@ -23,6 +23,14 @@
 
 int (*VDSO_SYMBOL(gettimeofday)) (struct timeval *, void *) attribute_hidden;
 int (*VDSO_SYMBOL(clock_gettime)) (clockid_t, struct timespec *);
+long (*VDSO_SYMBOL(clock_gettime64)) (clockid_t, struct __timespec64 *);
+
+int __y2038_linux_support;
+
+int __y2038_kernel_support (void)
+{
+  return __y2038_linux_support;
+}
 
 static inline void
 _libc_vdso_platform_setup (void)
@@ -36,6 +44,13 @@ _libc_vdso_platform_setup (void)
   p = _dl_vdso_vsym ("__vdso_clock_gettime", &linux26);
   PTR_MANGLE (p);
   VDSO_SYMBOL (clock_gettime) = p;
+
+  /* (aaribaud) TODO: map to version where clock_gettime64 officially appears */
+  p = _dl_vdso_vsym ("__vdso_clock_gettime64", NULL);
+  PTR_MANGLE (p);
+  VDSO_SYMBOL (clock_gettime64) = p;
+
+  __y2038_linux_support = (p != NULL) ? 1 : 0;
 }
 
 # define VDSO_SETUP _libc_vdso_platform_setup
diff --git a/sysdeps/unix/sysv/linux/arm/libc-vdso.h b/sysdeps/unix/sysv/linux/arm/libc-vdso.h
index ae37b574e1..ee0e5941c0 100644
--- a/sysdeps/unix/sysv/linux/arm/libc-vdso.h
+++ b/sysdeps/unix/sysv/linux/arm/libc-vdso.h
@@ -27,6 +27,7 @@
 extern int (*VDSO_SYMBOL(gettimeofday)) (struct timeval *, void *)
    attribute_hidden;
 extern int (*VDSO_SYMBOL(clock_gettime)) (clockid_t, struct timespec *);
+extern long (*VDSO_SYMBOL(clock_gettime64)) (clockid_t, struct __timespec64 *);
 
 #endif
 
diff --git a/sysdeps/unix/sysv/linux/clock_gettime.c b/sysdeps/unix/sysv/linux/clock_gettime.c
index e232f69a4f..df4e16e6db 100644
--- a/sysdeps/unix/sysv/linux/clock_gettime.c
+++ b/sysdeps/unix/sysv/linux/clock_gettime.c
@@ -44,4 +44,48 @@
   break
 #define SYSDEP_GETTIME_CPUTIME	/* Default catches them too.  */
 
+/* 64-bit versions */
+
+/* The REALTIME and MONOTONIC clock are definitely supported in the
+   kernel.  */
+#define SYSDEP_GETTIME64 \
+  SYSDEP_GETTIME64_CPUTIME;						      \
+  case CLOCK_REALTIME:							      \
+  case CLOCK_MONOTONIC:							      \
+    if (__y2038_linux_support)						      \
+      {									      \
+        retval = INLINE_VSYSCALL (clock_gettime64, 2, clock_id, tp);	      \
+      }									      \
+    else								      \
+      {									      \
+        retval = INLINE_VSYSCALL (clock_gettime, 2, clock_id, &ts32);	      \
+        if (retval==0)							      \
+          {								      \
+            tp->tv_sec = ts32.tv_sec;					      \
+            tp->tv_nsec = ts32.tv_nsec;					      \
+            tp->tv_pad = 0;						      \
+          }								      \
+      }									      \
+    break
+
+#define SYSDEP_GETTIME64_CPU(clock_id, tp) \
+  if (__y2038_linux_support)						      \
+    {									      \
+      retval = INLINE_VSYSCALL (clock_gettime64, 2, clock_id, tp);	      \
+    }									      \
+  else									      \
+    {									      \
+      retval = INLINE_VSYSCALL (clock_gettime, 2, clock_id, &ts32);	      \
+      if (retval==0)							      \
+        {								      \
+          tp->tv_sec = ts32.tv_sec;					      \
+          tp->tv_nsec = ts32.tv_nsec;					      \
+          tp->tv_pad = 0;						      \
+        }								      \
+    }									      \
+  break
+#define SYSDEP_GETTIME64_CPUTIME \
+  struct timespec ts32;							      \
+  extern int __y2038_linux_support;
+
 #include <sysdeps/unix/clock_gettime.c>
-- 
2.11.0