92

Unix/Linux 网络时间协议版本3 Network Time Protocol Version 3 (NTP) distribution for Unix systems

Replied: Tue, 18 Feb 1997 01:30:00 -0500
Replied: "Don Lewis <[e-mail]> "
Replied: Mon, 17 Feb 1997 20:23:09 -0500
Replied: "[e-mail] Don Lewis <[e-mail]>"
Replied: Mon, 17 Feb 1997 20:06:58 -0500
Replied: "Don Lewis <[e-mail]>, "Edward J. Huff" <[e-mail]> [e-mail]"
Replied: Mon, 17 Feb 1997 19:20:37 -0500
Replied: "Don Lewis <[e-mail]> "
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From: Don Lewis <[e-mail]>
Message-Id: <[e-mail]>
Date: Mon, 17 Feb 1997 00:59:25 -0800
In-Reply-To: [e-mail]
       "Re: xntp3-5.89.6 will be available soon" (Feb 14, 11:38pm)
X-Mailer: Mail User's Shell (7.2.6 alpha(3) 7/19/95)
To: [e-mail], Don Lewis <[e-mail]>
Subject: Re: xntp3-5.89.6 will be available soon
Cc: [e-mail]

On Feb 14, 11:38pm, [e-mail] wrote:
} Subject: Re: xntp3-5.89.6 will be available soon
} Not a lot of time right now.
} 
} I don't recall the failure mode offhand.
} 
} My original change to enable both SIGIO and NBIO was to change the code
} in ntp_io.c from:
} 
}  #ifdef HAVE_SIGNALED_IO		(about line 926)
}    init_socket_sig(fd);
}  #else /* not HAVE_SIGNALED_IO
}   ...
}  #endif /* HAVE_SIGNALED_IO */		(about line 966)
} 
} to:
} 
}  #ifdef HAVE_SIGNALED_IO		(about line 926)
}    init_socket_sig(fd);
}  #else /* not HAVE_SIGNALED_IO
}  #endif
}   ...
}  #if 0
}  #endif /* HAVE_SIGNALED_IO */		(about line 968)

That would be bad ... the code after init_socket_sig(fd) calls
fcntl(fd, F_SETFL, ...), which would turn off the FASYNC flag.
It's somewhat cleaner to do these in the opposite order, but
there's still once case in init_socket_sig() that has to be
handled specially.

Here's a patch vs. 3-5.89.7 with the following:

	The SunOS 4.x changes to configure.in for tick and tickadj

	The Solaris 2.x change to configure.in for tickadj

	Removing of the extra logging in ntpdate

	Cleanup of the #ifdef spaghetti for setting nonblocking I/O
	in open_socket, and async I/O in init_socket_sig()

	The call to init_socket_sig() is moved after nonblocking I/O
	is turned on, and it can be called in addition to making I/O
	nonblocking.

	The input_handler() routing is changed back to the 89.6 version
	with the following changes:

		Edward Huff's change to remove FD_CLR().
		(Hmn, this could be done in the case where recvfrom()
		fails because there was nothing for it to grab).

		All three flavors of non-blocking returns from recvfrom()
		are checked for so they don't cause errors to be logged.

		We don't goto select_again in case of a recvfrom() error.

I've got this running on SunOS 4.1.4, Solaris 2.5.1, HP-UX 9.0.5, and
FreeBSD 2.1.6.

Weaknesses of my testing are that none of these machines is multihomed
and we don't use broadcast mode, which is where I suspect the problem
of one packet setting multiple fd flags in the select() output comes from.

One thing that I'd suggest changing is getting rid of the outer for
loop in input_handler(), at least in the HAVE_SIGNALED_IO case,
because any packets that arrive while the handler is running will post
another signal, and the signal handler will be called again as soon as
it returns.  This change will reduce the number of times that the handler
will be called but will find nothing to do, and will save a number of
extra calls to select().

*** ORIGconfigure.in	Thu Feb 13 18:06:54 1997
--- configure.in	Mon Feb 17 00:07:44 1997
***************
*** 1814,1819 ****
--- 1814,1822 ----
        *-*-irix*)
  	 ans=10000
  	 ;;
+       *-*-sunos4*)
+ 	 ans=10000
+ 	 ;;
        *-*-linux*)
  	 ans=txc.tick
  	 ;;
***************
*** 1848,1853 ****
--- 1851,1859 ----
         no) ans=1000 ;;
        esac
        ;;
+    *-*-sunos4*)
+       ans='tick/2000'
+       ;;
     *-*-domainos)	# Skippy: won't be found...
        case "$ac_cv_var_can_kmem" in
         no) ans=668 ;;
***************
*** 1867,1873 ****
     *-*-solaris2*)
        case "$ac_cv_var_adjtime_is_accurate" in
         yes)
!           #ans='tick/16'
  	  ;;
        esac
        ;;
--- 1873,1879 ----
     *-*-solaris2*)
        case "$ac_cv_var_adjtime_is_accurate" in
         yes)
!           ans='tick/16'
  	  ;;
        esac
        ;;
*** ntpdate/ORIGntpdate.c	Wed Feb 12 16:50:05 1997
--- ntpdate/ntpdate.c	Sun Feb 16 22:30:31 1997
***************
*** 433,440 ****
  #endif /* SYS_WINNT */
  				 ) {
                                  msyslog(LOG_ERR, "select() error: %m");
-                         } else {
- 			  msyslog(LOG_DEBUG, "select(): nfound = %d, error: %m", nfound);
  			}
                          if (alarm_flag) {               /* alarmed? */
                                  was_alarmed = 1;
--- 433,438 ----
*** xntpd/ORIGntp_io.c	Wed Feb 12 16:36:42 1997
--- xntpd/ntp_io.c	Sun Feb 16 23:04:30 1997
***************
*** 923,937 ****
      maxactivefd = fd;
    FD_SET(fd, &activefds);
  
- #ifdef HAVE_SIGNALED_IO
-   init_socket_sig(fd);
- #else /* not HAVE_SIGNALED_IO */
- 
    /*
     * set non-blocking,
     */
  
! #if defined(O_NONBLOCK)
    if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0)
      {
        msyslog(LOG_ERR, "fcntl(O_NONBLOCK) fails: %m");
--- 923,933 ----
      maxactivefd = fd;
    FD_SET(fd, &activefds);
  
    /*
     * set non-blocking,
     */
  
! #if defined(O_NONBLOCK) /* POSIX */
    if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0)
      {
        msyslog(LOG_ERR, "fcntl(O_NONBLOCK) fails: %m");
***************
*** 938,968 ****
        exit(1);
        /*NOTREACHED*/
      }
! #else /* O_NONBLOCK */
! # if defined(FNDELAY)
    if (fcntl(fd, F_SETFL, FNDELAY) < 0)
      {
!       msyslog(LOG_ERR, "fcntl(FNDELAY) fails: %m");
        exit(1);
        /*NOTREACHED*/
      }
! # else /* FNDELAY */
! #  if defined(VMS) || defined(SYS_WINNT) /* VMS+UCX or SYS_WINNT */
! #   ifndef SYS_WINNT
    if (ioctl(fd,FIONBIO,&1) < 0)
! #   else
    if (ioctlsocket(fd,FIONBIO,(u_long *) &on) == SOCKET_ERROR)
! #   endif /* SYS_WINNT */
      {
        msyslog(LOG_ERR, "ioctl(FIONBIO) fails: %m");
        exit(1);
      }
! #  else
  #   include "Bletch: Need non blocking I/O!"
! #  endif /* VMS+UCX or SYS_WINNT */
! # endif /* FNDELAY */
! #endif /* O_NONBLOCK */
  
  #endif /* not HAVE_SIGNALED_IO */
  
    /*
--- 934,979 ----
        exit(1);
        /*NOTREACHED*/
      }
! #elif defined(FNDELAY)
    if (fcntl(fd, F_SETFL, FNDELAY) < 0)
      {
!       msyslog(LOG_ERR, "fcntl(O_NONBLOCK) fails: %m");
        exit(1);
        /*NOTREACHED*/
      }
! #elif defined(O_NDELAY) /* generally the same as FNDELAY */
!   if (fcntl(fd, F_SETFL, O_NDELAY) < 0)
!     {
!       msyslog(LOG_ERR, "fcntl(O_NONBLOCK) fails: %m");
!       exit(1);
!       /*NOTREACHED*/
!     }
! #elif defined(FIONBIO)
! # if defined(VMS)
    if (ioctl(fd,FIONBIO,&1) < 0)
! # elif defined(SYS_WINNT)
    if (ioctlsocket(fd,FIONBIO,(u_long *) &on) == SOCKET_ERROR)
! # else
!   if (ioctl(fd,FIONBIO,&on) < 0)
! # endif
      {
        msyslog(LOG_ERR, "ioctl(FIONBIO) fails: %m");
        exit(1);
+       /*NOTREACHED*/
      }
! #elif defined(FIOSNBIO)
!   if (ioctl(fd,FIOSNBIO,&on) < 0)
!     {
!       msyslog(LOG_ERR, "ioctl(FIOSNBIO) fails: %m");
!       exit(1);
!       /*NOTREACHED*/
!     }
! #else
  #   include "Bletch: Need non blocking I/O!"
! #endif
  
+ #ifdef HAVE_SIGNALED_IO
+   init_socket_sig(fd);
  #endif /* not HAVE_SIGNALED_IO */
  
    /*
***************
*** 1294,1299 ****
--- 1305,1311 ----
    return buffer;
  }
  
+ 
  /*
   * input_handler - receive packets asynchronously
   */
***************
*** 1362,1368 ****
  		  if (FD_ISSET(fd, &fds))
  		    {
  		      n--;
- 		      FD_CLR(fd, &fds); /* HMS: Added 961211 */
  		      if (free_recvbufs == 0)
  			{
  			  char buf[RX_BUFF_SIZE];
--- 1374,1379 ----
***************
*** 1460,1466 ****
  		  if (FD_ISSET(fd, &fds))
  		    {
  		      n--;
- 		      FD_CLR(fd, &fds); /* HMS: Added 961211 */
  
  		      /*
  		       * Get a buffer and read the frame.  If we
--- 1471,1476 ----
***************
*** 1519,1526 ****
  			}
  
  		      rb = freelist;
- 		      freelist = rb->next;
- 		      free_recvbufs--;
  
  		      fromlen = sizeof(struct sockaddr_in);
  		      rb->recv_length = recvfrom(fd,
--- 1529,1534 ----
***************
*** 1528,1548 ****
  						 sizeof(rb->recv_space), 0,
  						 (struct sockaddr *)&rb->recv_srcadr,
  						 &fromlen);
! 		      if (rb->recv_length == -1)
! 			{
  			  msyslog(LOG_ERR, "recvfrom() fd=%d: %m", fd);
- 			  rb->next = freelist;
- 			  freelist = rb;
- 			  free_recvbufs++;
  #ifdef DEBUG
  			  if (debug)
  			    printf("input_handler: fd=%d dropped (bad recvfrom)\n", fd);
  #endif
- #if 1
- 			  goto select_again;
- #else
  			  continue;
- #endif
  			}
  #ifdef DEBUG
  		      if (debug)
--- 1536,1563 ----
  						 sizeof(rb->recv_space), 0,
  						 (struct sockaddr *)&rb->recv_srcadr,
  						 &fromlen);
! 		      if (rb->recv_length > 0)
! 		        {
! 		          freelist = rb->next;
! 		          free_recvbufs--;
! 		        }
! 		      else if (rb->recv_length == 0
! #ifdef EWOULDBLOCK
! 			       || errno==EWOULDBLOCK
! #endif
! #ifdef EAGAIN
! 			       || errno==EAGAIN
! #endif
! 		              )
! 		        continue;
! 		      else
! 		        {
  			  msyslog(LOG_ERR, "recvfrom() fd=%d: %m", fd);
  #ifdef DEBUG
  			  if (debug)
  			    printf("input_handler: fd=%d dropped (bad recvfrom)\n", fd);
  #endif
  			  continue;
  			}
  #ifdef DEBUG
  		      if (debug)
***************
*** 1667,1673 ****
    return;
  }
  
- 
  /*
   * findinterface - utility used by other modules to find an interface
   *		   given an address.
--- 1682,1687 ----
***************
*** 1981,2007 ****
        exit(1);
      }
  }
! # else
! /*
!  * Socket SIGPOLL initialization routines.
!  * Special cases first!
!  */
! /* Was: defined(SYS_HPUX) || defined(SYS_LINUX) */
! #  if defined(FIOSNBIO) && defined(FIOASYNC)
! #define SOCKET_DONE
  {
!   int pgrp, on = 1;
  
!   /*
!    * Big difference here for HP-UX ... why can't life be easy ?
!    */
!   if (ioctl(fd, FIOSNBIO, (char *)&on) == -1)
!     {
!       msyslog(LOG_ERR, "ioctl(FIOSNBIO) fails: %m");
!       exit(1);
!       /*NOTREACHED*/
!     }
! 
    if (ioctl(fd, FIOASYNC, (char *)&on) == -1)
      {
        msyslog(LOG_ERR, "ioctl(FIOASYNC) fails: %m");
--- 1995,2008 ----
        exit(1);
      }
  }
! # else /* USE_UDP_SIGPOLL */
  {
!   int pgrp;
! # ifdef FIOASYNC
!   int on = 1;
! # endif
  
! #  if defined(FIOASYNC)
    if (ioctl(fd, FIOASYNC, (char *)&on) == -1)
      {
        msyslog(LOG_ERR, "ioctl(FIOASYNC) fails: %m");
***************
*** 2008,2019 ****
        exit(1);
        /*NOTREACHED*/
      }
  
! #   ifdef UDP_BACKWARDS_SETOWN
    pgrp = -getpid();
! #   else
    pgrp = getpid();
! #   endif
    if (ioctl(fd, SIOCSPGRP, (char *)&pgrp) == -1)
      {
        msyslog(LOG_ERR, "ioctl(SIOCSPGRP) fails: %m");
--- 2009,2042 ----
        exit(1);
        /*NOTREACHED*/
      }
+ #  elif defined(FASYNC)
+   {
+     int flags;
  
!     if ((flags = fcntl(fd, F_GETFL, 0)) == -1)
!       {
!         msyslog(LOG_ERR, "fcntl(F_GETFL) fails: %m");
!         exit(1);
!         /*NOTREACHED*/
!       }
!     if (fcntl(fd, F_SETFL, flags|FASYNC) < 0)
!       {
!         msyslog(LOG_ERR, "fcntl(...|FASYNC) fails: %m");
!         exit(1);
!         /*NOTREACHED*/
!       }
!    }
! #  else
! #   include "Bletch: Need asynchronous I/O!"
! #  endif
! 
! #  ifdef UDP_BACKWARDS_SETOWN
    pgrp = -getpid();
! #  else
    pgrp = getpid();
! #  endif
! 
! #  if defined(SIOCSPGRP)
    if (ioctl(fd, SIOCSPGRP, (char *)&pgrp) == -1)
      {
        msyslog(LOG_ERR, "ioctl(SIOCSPGRP) fails: %m");
***************
*** 2020,2043 ****
        exit(1);
        /*NOTREACHED*/
      }
! }
! #  endif /* SYS_HPUX || SYS_LINUX: FIOSNBIO && FIOASYNC */
! /* Was:  defined(SYS_AIX) && !defined(_BSD) */
! #  if !defined(_BSD) && defined(_AIX) && defined(FIOASYNC) && defined(FIOSETOWN)
! /*
!  * SYSV compatibility mod under AIX
!  */
! #define SOCKET_DONE
! {
!   int pgrp, on = 1;
! 
!   if (ioctl(fd, FIOASYNC, (char *)&on) == -1)
!     {
!       msyslog(LOG_ERR, "ioctl(FIOASYNC) fails: %m");
!       exit(1);
!       /*NOTREACHED*/
!     }
!   pgrp = -getpid();
    if (ioctl(fd, FIOSETOWN, (char*)&pgrp) == -1)
      {
        msyslog(LOG_ERR, "ioctl(FIOSETOWN) fails: %m");
--- 2043,2049 ----
        exit(1);
        /*NOTREACHED*/
      }
! #  elif defined(FIOSETOWN)
    if (ioctl(fd, FIOSETOWN, (char*)&pgrp) == -1)
      {
        msyslog(LOG_ERR, "ioctl(FIOSETOWN) fails: %m");
***************
*** 2044,2087 ****
        exit(1);
        /*NOTREACHED*/
      }
! 
!   if (fcntl(fd, F_SETFL, FNDELAY|FASYNC) < 0)
      {
-       msyslog(LOG_ERR, "fcntl(FNDELAY|FASYNC) fails: %m");
-       exit(1);
-       /*NOTREACHED*/
-     }
- }
- #  endif /* AIX && !BSD: !_BSD && FIOASYNC && FIOSETOWN */
- #  ifndef SOCKET_DONE
- {
-   int pid = getpid();
- 
- #   if defined(UDP_BACKWARDS_SETOWN)
-   /*
-    * The way Sun did it as recently as SunOS 3.5.  Only
-    * in the case of sockets, of course, just to confuse
-    * the issue.  Don't they even bother to test the stuff
-    * they send out?  Ibid for Ultrix 2.0
-    */
-   pid = -pid;
- #   endif /* UDP_BACKWARDS_SETOWN */
-   if (fcntl(fd, F_SETOWN, pid) == -1)
-     {
        msyslog(LOG_ERR, "fcntl(F_SETOWN) fails: %m");
        exit(1);
-     }
-   /*
-    * set non-blocking, async I/O on the descriptor
-    */
-   if (fcntl(fd, F_SETFL, FNDELAY|FASYNC) < 0)
-     {
-       msyslog(LOG_ERR, "fcntl(FNDELAY|FASYNC) fails: %m");
-       exit(1);
        /*NOTREACHED*/
      }
  }
- #  endif /* SOCKET_DONE */
  # endif /* USE_UDP_SIGPOLL */
  
  
--- 2050,2066 ----
        exit(1);
        /*NOTREACHED*/
      }
! #  elif defined(F_SETOWN)
!   if (fcntl(fd, F_SETOWN, pgrp) == -1)
      {
        msyslog(LOG_ERR, "fcntl(F_SETOWN) fails: %m");
        exit(1);
        /*NOTREACHED*/
      }
+ #  else
+ #   include "Bletch: Need to set process(group) to receive SIG(IO|POLL)"
+ #  endif
  }
  # endif /* USE_UDP_SIGPOLL */
  
  

			---  Truck