From ae18718f58a619abf463eca538c497972d24e173 Mon Sep 17 00:00:00 2001
From: Ulrich Drepper <drepper@redhat.com>
Date: Mon, 10 Dec 2007 23:51:42 +0000
Subject: * sysdeps/unix/sysv/linux/adjtime.c: Use ADJ_OFFSET_SS_READ if

	possible.
	* sysdeps/unix/sysv/linux/kernel-features.h
	(__ASSUME_ADJ_OFFSET_SS_READ): Define for 2.6.24.
	* sysdeps/unix/sysv/linux/sys/timex.h (ADJ_OFFSET_SS_READ): Define.
---
 ChangeLog                                 |  8 ++++++++
 sysdeps/unix/sysv/linux/adjtime.c         | 24 +++++++++++++++++++++---
 sysdeps/unix/sysv/linux/kernel-features.h |  5 +++++
 sysdeps/unix/sysv/linux/sys/timex.h       |  3 ++-
 4 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 560a6e6cc1..c94d0e4cfd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2007-12-10  Ulrich Drepper  <drepper@redhat.com>
+
+	* sysdeps/unix/sysv/linux/adjtime.c: Use ADJ_OFFSET_SS_READ if
+	possible.
+	* sysdeps/unix/sysv/linux/kernel-features.h
+	(__ASSUME_ADJ_OFFSET_SS_READ): Define for 2.6.24.
+	* sysdeps/unix/sysv/linux/sys/timex.h (ADJ_OFFSET_SS_READ): Define.
+
 2007-12-08  Ulrich Drepper  <drepper@redhat.com>
 
 	[BZ #5424]
diff --git a/sysdeps/unix/sysv/linux/adjtime.c b/sysdeps/unix/sysv/linux/adjtime.c
index 38ef805cd5..202bb14485 100644
--- a/sysdeps/unix/sysv/linux/adjtime.c
+++ b/sysdeps/unix/sysv/linux/adjtime.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1995, 1996, 1997, 1998, 2002, 2004
+/* Copyright (C) 1995, 1996, 1997, 1998, 2002, 2004, 2007
    Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
@@ -22,6 +22,8 @@
 #include <sys/time.h>
 #include <sys/timex.h>
 
+#include <kernel-features.h>
+
 #define MAX_SEC	(INT_MAX / 1000000L - 2)
 #define MIN_SEC	(INT_MIN / 1000000L + 2)
 
@@ -69,13 +71,29 @@ ADJTIME (const struct TIMEVAL *itv, struct TIMEVAL *otv)
 	  return -1;
 	}
       tntx.offset = tmp.tv_usec + tmp.tv_sec * 1000000L;
+#ifdef ADJ_OFFSET_SS_READ
+      tntx.modes = ADJ_OFFSET_SS_READ;
+#else
       tntx.modes = ADJ_OFFSET_SINGLESHOT;
+#endif
     }
   else
     tntx.modes = 0;
 
-  if (ADJTIMEX (&tntx) < 0)
-    return -1;
+#if defined ADJ_OFFSET_SS_READ && !defined __ASSUME_ADJ_OFFSET_SS_READ
+ again:
+#endif
+  if (__builtin_expect (ADJTIMEX (&tntx) < 0, 0))
+    {
+#if defined ADJ_OFFSET_SS_READ && !defined __ASSUME_ADJ_OFFSET_SS_READ
+      if (itv && errno == EINVAL && tntx.modes == ADJ_OFFSET_SS_READ)
+	{
+	  tntx.modes = ADJ_OFFSET_SINGLESHOT;
+	  goto again;
+	}
+#endif
+      return -1;
+    }
 
   if (otv)
     {
diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h
index aab3df348e..01baab0903 100644
--- a/sysdeps/unix/sysv/linux/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/kernel-features.h
@@ -487,3 +487,8 @@
 	|| (__LINUX_KERNEL_VERSION >= 0x020618 && defined __s390__))
 # define __ASSUME_FALLOCATE	1
 #endif
+
+/* Support for ADJ_OFFSET_SS_READ was added in 2.6.24.  */
+#if __LINUX_KERNEL_VERSION >= 0x020618
+# define __ASSUME_ADJ_OFFSET_SS_READ	1
+#endif
diff --git a/sysdeps/unix/sysv/linux/sys/timex.h b/sysdeps/unix/sysv/linux/sys/timex.h
index 773a5ab8d0..f7bd6e7929 100644
--- a/sysdeps/unix/sysv/linux/sys/timex.h
+++ b/sysdeps/unix/sysv/linux/sys/timex.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 1995, 1996, 1997, 1999 Free Software Foundation, Inc.
+/* Copyright (C) 1995, 1996, 1997, 1999, 2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -69,6 +69,7 @@ struct timex
 #define ADJ_TIMECONST		0x0020	/* pll time constant */
 #define ADJ_TICK		0x4000	/* tick value */
 #define ADJ_OFFSET_SINGLESHOT	0x8001	/* old-fashioned adjtime */
+#define ADJ_OFFSET_SS_READ	0xa001	/* read-only adjtime */
 
 /* xntp 3.4 compatibility names */
 #define MOD_OFFSET	ADJ_OFFSET
-- 
cgit 1.4.1