Record High Load Average - due to SunOS 4.0 rwhod

[Mark Plotnick]

SunOS 4.0 users may have seen things like

rubato      up    12:45,     0 users,  load 1242604.92, 535.62,  0.00

due to bogus information being broadcast by rwhod.  A bad interaction
with Yellow Pages (isn't that a tautology?) is the culprit.  It looks like
YP depends on some file descriptors being kept open across calls.
rwhod closes all descriptors between 0 and 9, and does so after the
Yellow Pages has been initialized.  And it turns out that the problem
goes away when you #define DEBUG to take a closer look at the problem,
because the close() calls are bracketed by #ifndef DEBUG/#endif !

Here's my fix.  I also renamed the debugging version of sendto() that
rwhod provides so that it wouldn't mistakenly be called by Yellow Pages
routines.


*** rwhod.orig.c	Fri Aug 26 10:50:37 1988
--- rwhod.c	Fri Aug 26 11:04:57 1988
***************
*** 105,112 ****
  	if (fork())
  		exit(0);
  	{ int s;
! 	  for (s = 0; s < 10; s++)
  		(void) close(s);
  	  (void) open("/", 0);
  	  (void) dup2(0, 1);
  	  (void) dup2(0, 2);
--- 105,115 ----
  	if (fork())
  		exit(0);
  	{ int s;
! 	  for (s = getdtablesize()-10; s < getdtablesize(); s++)
  		(void) close(s);
+ 	  (void) close(0);
+ 	  (void) close(1);
+ 	  (void) close(2);
  	  (void) open("/", 0);
  	  (void) dup2(0, 1);
  	  (void) dup2(0, 2);
***************
*** 338,346 ****
  	mywd.wd_sendtime = htonl(time(0));
  	mywd.wd_vers = WHODVERSION;
  	mywd.wd_type = WHODTYPE_STATUS;
! 	for (np = neighbors; np != NULL; np = np->n_next)
  		(void) sendto(s, (char *)&mywd, cc, 0,
  			np->n_addr, np->n_addrlen);
  	if (utmpent && chdir(RWHODIR)) {
  		syslog(LOG_ERR, "chdir(%s): %m", RWHODIR);
  		exit(1);
--- 341,354 ----
  	mywd.wd_sendtime = htonl(time(0));
  	mywd.wd_vers = WHODVERSION;
  	mywd.wd_type = WHODTYPE_STATUS;
! 	for (np = neighbors; np != NULL; np = np->n_next) {
  		(void) sendto(s, (char *)&mywd, cc, 0,
  			np->n_addr, np->n_addrlen);
+ #ifdef DEBUG
+ 		(void) mysendto(s, (char *)&mywd, cc, 0,
+ 			np->n_addr, np->n_addrlen);
+ #endif
+ 	}
  	if (utmpent && chdir(RWHODIR)) {
  		syslog(LOG_ERR, "chdir(%s): %m", RWHODIR);
  		exit(1);
***************
*** 470,476 ****
  }
  
  #ifdef DEBUG
! sendto(s, buf, cc, flags, to, tolen)
  	int s;
  	char *buf;
  	int cc, flags;
--- 478,484 ----
  }
  
  #ifdef DEBUG
! mysendto(s, buf, cc, flags, to, tolen)
  	int s;
  	char *buf;
  	int cc, flags;

--
	Mark Plotnick
	andante!mp or allegra!mp