Use monotonic time source if available.

  Changelog for the c-ares project

* May 9 2008 (Yang Tse)

- Use monotonic time source if available, for private function ares__tvnow()

* May 7 2008 (Daniel Stenberg)

- Sebastian made c-ares able to return all PTR-records when doing reverse

ares_expand_name.c ares_parse_a_reply.c windows_port.c			\

ares_expand_string.c ares_parse_ptr_reply.c ares_parse_aaaa_reply.c	\

ares_getnameinfo.c inet_net_pton.c bitncmp.c inet_ntop.c		\

ares_parse_ns_reply.c ares_llist.c

ares_parse_ns_reply.c ares_llist.c ares__timeval.c

HHEADERS = ares.h ares_private.h setup.h ares_dns.h ares_version.h          \

           nameser.h inet_net_pton.h inet_ntop.h ares_ipv6.h bitncmp.h      \

          $(OBJ_DIR)\ares_init.obj             \

          $(OBJ_DIR)\ares_llist.obj            \

          $(OBJ_DIR)\ares_timeout.obj          \

          $(OBJ_DIR)\ares__timeval.obj         \

          $(OBJ_DIR)\ares_destroy.obj          \

          $(OBJ_DIR)\ares_mkquery.obj          \

          $(OBJ_DIR)\ares_version.obj          \

       @echo   ares_inet_pton         >> $@

       @echo   ares_writev            >> $@

       @echo   ares_getnameinfo       >> $@

       @echo   ares_gettimeofday      >> $@

       @echo   ares_parse_aaaa_reply  >> $@

ahost.exe: $(OBJ_DIR) $(OBJ_DIR)\ahost.obj $(OBJ_DIR)\ares_getopt.obj cares_imp.lib

$(OBJ_DIR)\ares_timeout.obj: ares_timeout.c setup.h setup_once.h ares.h        \

  ares_private.h ares_ipv6.h

$(OBJ_DIR)\ares__timeval.obj: ares__timeval.c setup.h setup_once.h ares.h      \

  ares_private.h ares_ipv6.h

$(OBJ_DIR)\ares_destroy.obj: ares_destroy.c setup.h setup_once.h ares.h        \

  ares_private.h ares_ipv6.h

This is what's new and changed in the c-ares 1.5.2 release:

 o improved parsing of resolver configuration files

 o use monotonic time source if available

Thanks go to these friendly people for their efforts and contributions:

/* $Id$ */

/* Copyright (C) 2008 by Daniel Stenberg et al

 *

 * Permission to use, copy, modify, and distribute this software and its

 * documentation for any purpose and without fee is hereby granted, provided

 * that the above copyright notice appear in all copies and that both that

 * copyright notice and this permission notice appear in supporting

 * documentation, and that the name of M.I.T. not be used in advertising or

 * publicity pertaining to distribution of the software without specific,

 * written prior permission.  M.I.T. makes no representations about the

 * suitability of this software for any purpose.  It is provided "as is"

 * without express or implied warranty.

 */

#include "setup.h"

#include "ares.h"

#include "ares_private.h"

#if defined(WIN32) && !defined(MSDOS)

struct timeval ares__tvnow(void)

{

  /*

  ** GetTickCount() is available on _all_ Windows versions from W95 up

  ** to nowadays. Returns milliseconds elapsed since last system boot,

  ** increases monotonically and wraps once 49.7 days have elapsed.

  */

  struct timeval now;

  DWORD milliseconds = GetTickCount();

  now.tv_sec = milliseconds / 1000;

  now.tv_usec = (milliseconds % 1000) * 1000;

  return now;

}

#elif defined(HAVE_CLOCK_GETTIME) && defined(CLOCK_MONOTONIC)

struct timeval ares__tvnow(void)

{

  /*

  ** clock_gettime() is granted to be increased monotonically when the

  ** monotonic clock is queried. Time starting point is unspecified, it

  ** could be the system start-up time, the Epoch, or something else,

  ** in any case the time starting point does not change once that the

  ** system has started up.

  */

  struct timeval now;

  struct timespec tsnow;

  (void)clock_gettime(CLOCK_MONOTONIC, &tsnow)

  now.tv_sec = tsnow.tv_sec;

  now.tv_usec = tsnow.tv_nsec / 1000;

  return now;

}

#elif defined(HAVE_GETTIMEOFDAY)

struct timeval ares__tvnow(void)

{

  /*

  ** gettimeofday() is not granted to be increased monotonically, due to

  ** clock drifting and external source time synchronization it can jump

  ** forward or backward in time.

  */

  struct timeval now;

  (void)gettimeofday(&now, NULL);

  return now;

}

#else

struct timeval ares__tvnow(void)

{

  /*

  ** time() returns the value of time in seconds since the Epoch.

  */

  struct timeval now;

  now.tv_sec = (long)time(NULL);

  now.tv_usec = 0;

  return now;

}

#endif

/*

 * Make sure that the first argument is the more recent time, as otherwise

 * we'll get a weird negative time-diff back...

 *

 * Returns: the time difference in number of milliseconds.

 */

long ares__tvdiff(struct timeval newer, struct timeval older)

{

  return (newer.tv_sec-older.tv_sec)*1000+

    (newer.tv_usec-older.tv_usec)/1000;

}