Re: prob: fg not sending CONT to 'make' children

["Bart Schaefer" <schaefer@xxxxxxxxxxxxxxxxxxxxxxx>]

On Aug 31,  1:25pm, Sven Wischnowsky wrote:
} Subject: Re: prob: fg not sending CONT to 'make' children
}
} The patch below makes the return value be -1 if at least one of the
} kill()s failed.

Really?  It doesn't look to me as though it changes that behavior at all.
And all those #ifdefs make it really hard to read, and testing sig != 0 is
redundant because the whole thing is inside "if (sig == SIGCONT) ...".

} NOTE: while playing with this I found a bug when I did `ls|sleep 800'
} where the `ls' finished before the `sleep' process was set up -- the
} `sleep' put itself in its own little process group and one couldn't fg 
} the whole thing. I tried several ways to fix this now and the hunks in 
} `exec.c' and `utils.c' are the only ones which made this work

That's very odd.  I didn't think the PID passed to killpg() should change
if you still want to signal the whole group, even if the group leader had
exited.  I wonder what happens if there are more than two processes in
the group when the leader exits?  Do all the leader's children become
their own little leaders?

Hmm, this is something I used to know, about 12 years ago ...

Index: Src/jobs.c
===================================================================
@@ -835,11 +835,7 @@
 
     /* child_block() around this loop in case #ifndef WNOHANG */
     child_block();		/* unblocked in child_suspend() */
-#ifdef BROKEN_KILL_ESRCH
-    while (!errflag && (kill(pid, 0) >= 0 || (errno != ESRCH && errno != EINVAL))) {
-#else /* not BROKEN_KILL_ESRCH */
     while (!errflag && (kill(pid, 0) >= 0 || errno != ESRCH)) {
-#endif /* BROKEN_KILL_ESRCH */
 	if (first)
 	    first = 0;
 	else
Index: Src/signals.c
===================================================================
@@ -593,38 +593,23 @@
                 for (pn = jobtab[jn->other].procs; pn; pn = pn->next)
                     if (killpg(pn->pid, sig) == -1)
 			if (kill(pn->pid, sig) == -1 && errno != ESRCH)
-#ifdef BROKEN_KILL_ESRCH
-			    if(errno != EINVAL || sig != 0)
-#endif /* BROKEN_KILL_ESRCH */
-				err = -1;
+			    err |= -1;
  
                 for (pn = jn->procs; pn->next; pn = pn->next)
                     if (kill(pn->pid, sig) == -1 && errno != ESRCH)
-#ifdef BROKEN_KILL_ESRCH
-			if(errno != EINVAL || sig != 0)
-#endif /* BROKEN_KILL_ESRCH */
-			    err = -1;
+			err |= -1;
 
 		if (!jobtab[jn->other].procs && pn)
 		    if (kill(pn->pid, sig) == -1 && errno != ESRCH)
-#ifdef BROKEN_KILL_ESRCH
-			if(errno != EINVAL || sig != 0)
-#endif /* BROKEN_KILL_ESRCH */
-			    err = -1;
+			err |= -1;
 
                 return err;
             }
             if (killpg(jobtab[jn->other].gleader, sig) == -1 && errno != ESRCH)
-#ifdef BROKEN_KILL_ESRCH
-		if(errno != EINVAL || sig != 0)
-#endif /* BROKEN_KILL_ESRCH */
-		    err = -1;
+		err = -1;
 		
 	    if (killpg(jn->gleader, sig) == -1 && errno != ESRCH)
-#ifdef BROKEN_KILL_ESRCH
-		if(errno != EINVAL || sig != 0)
-#endif /* BROKEN_KILL_ESRCH */
-		    err = -1;
+		err |= -1;
 
 	    return err;
         }
@@ -632,10 +617,7 @@
 	    return killpg(jn->gleader, sig);
     }
     for (pn = jn->procs; pn; pn = pn->next)
-        if ((err = kill(pn->pid, sig)) == -1 && errno != ESRCH)
-#ifdef BROKEN_KILL_ESRCH
-          if(errno != EINVAL || sig != 0)
-#endif /* BROKEN_KILL_ESRCH */
+        if ((err = kill(pn->pid, sig)) == -1 && errno != ESRCH && sig != 0)
             return -1;
     return err;
 }
Index: Src/system.h
===================================================================
@@ -620,3 +620,8 @@
 #ifdef BROKEN_TCSETPGRP
 #undef JOB_CONTROL
 #endif /* BROKEN_TCSETPGRP */
+
+#ifdef BROKEN_KILL_ESRCH
+#undef ESRCH
+#define ESRCH EINVAL
+#endif /* BROKEN_KILL_ESRCH */

-- 
Bart Schaefer                                 Brass Lantern Enterprises
http://www.well.com/user/barts              http://www.brasslantern.com