Re: PATCH: that execution stuff

[Sven Wischnowsky <wischnow@informatik.hu-berlin.de>]

Bart Schaefer wrote:

> Thanks, Sven; this finally seems to have nailed the critical bits.

Ha. One thing I knew already about yesterday:

  % f() { while read a; do :; done; mutt }
  % cat foo | f

The important bit is that mutt is started when the cat has finished.
In this case it is put in the group of the parent shell. Bing! Something
similar happens when we ^Z such a thing when the beginning of the
pipeline has already exited (the sub-shell is left in the group of the 
parent shell).

While trying to fix this I also found another one:

  % f() { cat builtin.c }
  % f | while read a; do :; done

Then ^Z it and try to fg it -- nothing happens. The sub-shell for the
function is not continued correctly.

There were some other things (like the sub-shell not continuing the
cat in the second example) I found and which should be fixed now, but
I don't really remember them. Some were probably caused by me trying
to get these two to work.

If someone feels adventurous and has spare time (ha!), he could
probably try more of these combinations (^Z'ing, fg'ing, ^C'ing loops, 
function, pipes, combinations of all of them) and tell us if he finds
something that still doesn't work.
  

Bye
 Sven

P.S.:   If you have the impression that the execution code is getting
        more and more complicated, you are right.
P.P.S.: Execution code is really hard to bug. Sigh.

diff -u os/exec.c Src/exec.c
--- os/exec.c	Tue Jun 29 17:25:48 1999
+++ Src/exec.c	Wed Jun 30 11:51:09 1999
@@ -903,7 +903,7 @@
 
 		    /* If the super-job contains only the sub-shell, the
 		       sub-shell is the group leader. */
-		    if (!jn->procs->next)
+		    if (!jn->procs->next || lpforked == 2)
 			jn->gleader = list_pipe_pid;
 
 		    for (pn = jobtab[jn->other].procs; pn; pn = pn->next)
@@ -961,7 +961,8 @@
 		    else if (pid) {
 			char dummy;
 
-			lpforked = 1;
+			lpforked = 
+			    (killpg(jobtab[list_pipe_job].gleader, 0) == -1 ? 2 : 1);
 			list_pipe_pid = pid;
 			nowait = errflag = 1;
 			breaks = loops;
@@ -983,9 +984,12 @@
 		    else {
 			close(synch[0]);
 			entersubsh(Z_ASYNC, 0, 0);
-			if (jobtab[list_pipe_job].procs)
-			    setpgrp(0L, mypgrp = jobtab[list_pipe_job].gleader);
-			else
+			if (jobtab[list_pipe_job].procs) {
+			    if (setpgrp(0L, mypgrp = jobtab[list_pipe_job].gleader)
+				== -1) {
+				setpgrp(0L, mypgrp = getpid());
+			    }
+			} else
 			    setpgrp(0L, mypgrp = getpid());
 			close(synch[1]);
 			kill(getpid(), SIGSTOP);
@@ -2206,9 +2210,8 @@
 	    if (kill(jobtab[list_pipe_job].gleader, 0) == -1 ||
 		setpgrp(0L, jobtab[list_pipe_job].gleader) == -1) {
 		jobtab[list_pipe_job].gleader =
-		    jobtab[thisjob].gleader = mypgrp;
-		setpgrp(0L, mypgrp);
-
+		    jobtab[thisjob].gleader = (list_pipe_child ? mypgrp : getpid());
+		setpgrp(0L, jobtab[list_pipe_job].gleader);
 		if (how & Z_SYNC)
 		    attachtty(jobtab[thisjob].gleader);
 	    }
diff -u os/jobs.c Src/jobs.c
--- os/jobs.c	Tue Jun 29 12:51:16 1999
+++ Src/jobs.c	Wed Jun 30 11:51:48 1999
@@ -787,9 +787,13 @@
 	       what this might be.  --oberon
 
 	    errflag = 0; */
+	    if (subsh) {
+		killjb(jn, SIGCONT);
+		jn->stat &= ~STAT_STOPPED;
+	    }
 	    if (jn->stat & STAT_SUPERJOB) {
 		Job sj = jobtab + jn->other;
-		if (sj->stat & STAT_DONE) {
+		if ((sj->stat & STAT_DONE) || !sj->procs) {
 		    struct process *p;
 		    
 		    for (p = sj->procs; p; p = p->next)
@@ -803,11 +807,18 @@
 			    break;
 			}
 		    if (!p) {
+			int cp;
+
 			jn->stat &= ~STAT_SUPERJOB;
 			jn->stat |= STAT_WASSUPER;
-			if (WIFEXITED(jn->procs->status) &&
-			    killpg(jn->gleader, 0) == -1)
-			    jn->gleader = mypgrp;
+
+			if ((cp = ((WIFEXITED(jn->procs->status) ||
+				    WIFSIGNALED(jn->procs->status)) &&
+				   killpg(jn->gleader, 0) == -1))) {
+			    Process p;
+			    for (p = jn->procs; p->next; p = p->next);
+			    jn->gleader = p->pid;
+			}
 			/* This deleted the job too early if the parent
 			   shell waited for a command in a list that will
 			   be executed by the sub-shell (e.g.: if we have
@@ -819,7 +830,7 @@
 			/* If this super-job contains only the sub-shell,
 			   we have to attach the tty to our process group
 			   (which is shared by the sub-shell) now. */
-			if (!jn->procs->next)
+			if (!jn->procs->next || cp || jn->procs->pid != jn->gleader)
 			    attachtty(jn->gleader);
 			kill(sj->other, SIGCONT);
 		    }
@@ -830,7 +841,9 @@
 
 		    jn->stat |= STAT_STOPPED;
 		    for (p = jn->procs; p; p = p->next)
-			p->status = sj->procs->status;
+			if (p->status == SP_RUNNING ||
+			    (!WIFEXITED(p->status) && !WIFSIGNALED(p->status)))
+			    p->status = sj->procs->status;
 		    curjob = jn - jobtab;
 		    printjob(jn, !!isset(LONGLISTJOBS), 1);
 		    break;
@@ -1250,7 +1263,10 @@
 		if (func != BIN_WAIT) {		/* fg */
 		    thisjob = job;
 		    if ((jobtab[job].stat & STAT_SUPERJOB) &&
-			!jobtab[job].procs->next)
+			((!jobtab[job].procs->next ||
+			  WIFEXITED(jobtab[job].procs->status) ||
+			  WIFSIGNALED(jobtab[job].procs->status))) &&
+			jobtab[jobtab[job].other].gleader)
 			attachtty(jobtab[jobtab[job].other].gleader);
 		    else
 			attachtty(jobtab[job].gleader);
diff -u os/signals.c Src/signals.c
--- os/signals.c	Tue Jun 29 12:51:17 1999
+++ Src/signals.c	Wed Jun 30 11:43:50 1999
@@ -586,7 +586,10 @@
  
                 for (pn = jn->procs; pn->next; pn = pn->next)
                     err = kill(pn->pid, sig);
- 
+
+		if (!jobtab[jn->other].procs && pn)
+		    err = kill(pn->pid, sig);
+
                 return err;
             }
  

--
Sven Wischnowsky                         wischnow@informatik.hu-berlin.de