Attachment 32048 Details for Bug 25624 – Use monotonic clock for _dbus_get_current_time() if it's available

[patch] Use monotonic clock for _dbus_get_current_time() if it's available

0001-Use-monotonic-clock-for-_dbus_get_current_time-if.patch (text/plain), 1.91 KB, created by Tom Hughes on 2009-12-13 13:46:13 UTC

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Creator: Tom Hughes

Created: 2009-12-13 13:46:13 UTC

Size: 1.91 KB

patch

obsolete

>From ed745042e03c383f6ca4387e59078a5616b314e1 Mon Sep 17 00:00:00 2001
>From: Tom Hughes <tom.hughes@palm.com>
>Date: Sun, 13 Dec 2009 13:30:09 -0800
>Subject: [PATCH] Use monotonic clock for _dbus_get_current_time() if it's available.
>
>_dbus_get_current_time() is used for timeouts, but uses gettimeofday(), which
>relies on the wall clock time, which can change. If the time is changed forwards
>or backwards, the timeouts are no longer valid, so the monotonic clock must be used.
>---
> configure.in             |    3 +++
> dbus/dbus-sysdeps-unix.c |   13 ++++++++++++-
> 2 files changed, 15 insertions(+), 1 deletions(-)
>
>diff --git a/configure.in b/configure.in
>index 7ef6632..6000dc4 100644
>--- a/configure.in
>+++ b/configure.in
>@@ -922,6 +922,9 @@ if test x$dbus_win = xyes ; then
>   NETWORK_libs="-lws2_32"
> fi
> 
>+# librt detection
>+AC_CHECK_LIB(rt, clock_gettime)
>+
> #### Set up final flags
> DBUS_CLIENT_CFLAGS=
> DBUS_CLIENT_LIBS="$THREAD_LIBS $NETWORK_libs"
>diff --git a/dbus/dbus-sysdeps-unix.c b/dbus/dbus-sysdeps-unix.c
>index eb6f963..c583b6e 100644
>--- a/dbus/dbus-sysdeps-unix.c
>+++ b/dbus/dbus-sysdeps-unix.c
>@@ -2399,7 +2399,8 @@ _dbus_poll (DBusPollFD *fds,
> }
> 
> /**
>- * Get current time, as in gettimeofday().
>+ * Get current time, as in gettimeofday(). Use the monotonic clock if
>+ * available, to avoid problems when the system time changes.
>  *
>  * @param tv_sec return location for number of seconds
>  * @param tv_usec return location for number of microseconds (thousandths)
>@@ -2410,12 +2411,22 @@ _dbus_get_current_time (long *tv_sec,
> {
>   struct timeval t;
> 
>+#if defined(_POSIX_TIMERS) && defined(_POSIX_MONOTONIC_CLOCK)
>+  struct timespec ts;
>+  clock_gettime(CLOCK_MONOTONIC, &ts);
>+
>+  if (tv_sec)
>+    *tv_sec = ts.tv_sec;
>+  if (tv_usec)
>+    *tv_usec = ts.tv_nsec / 1000;
>+#else
>   gettimeofday (&t, NULL);
> 
>   if (tv_sec)
>     *tv_sec = t.tv_sec;
>   if (tv_usec)
>     *tv_usec = t.tv_usec;
>+#endif
> }
> 
> /**
>-- 
>1.5.4.3
>

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