Re: zsh: Strange feature with 'jobs' commmand

[Peter Stephenson <pws@xxxxxxx>]

=?iso-8859-1?Q?Bj=F6rn_Johannesson?= wrote:
> Hi.
> 
> If you start a few jobs in the background and do:
> zsh% jobs
> [1]  - running    xmixer
> [2]  + running    gtcd
> zsh% _
> 
> ok, this is expected but this is not...
> zsh% jobs | less
> (END)

This annoys everybody.

The problem is fairly localised: you only need to list jobs in
subshells, and the subshells will not be changing the status of jobs.
So maybe something relatively straightforward like the following is good
enough.

Index: Src/exec.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/exec.c,v
retrieving revision 1.41
diff -u -r1.41 exec.c
--- Src/exec.c	6 May 2002 14:46:11 -0000	1.41
+++ Src/exec.c	30 May 2002 15:12:37 -0000
@@ -2507,13 +2507,13 @@
 static void
 entersubsh(int how, int cl, int fake)
 {
-    int sig;
+    int sig, monitor;
 
     if (cl != 2)
 	for (sig = 0; sig < VSIGCOUNT; sig++)
 	    if (!(sigtrapped[sig] & ZSIG_FUNC))
 		unsettrap(sig);
-    if (unset(MONITOR)) {
+    if (!(monitor = isset(MONITOR))) {
 	if (how & Z_ASYNC) {
 	    settrap(SIGINT, NULL);
 	    settrap(SIGQUIT, NULL);
@@ -2569,7 +2569,7 @@
     opts[MONITOR] = opts[USEZLE] = 0;
     zleactive = 0;
     if (cl)
-	clearjobtab();
+	clearjobtab(monitor);
     times(&shtms);
     forklevel = locallevel;
 }
Index: Src/jobs.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/jobs.c,v
retrieving revision 1.15
diff -u -r1.15 jobs.c
--- Src/jobs.c	21 Dec 2001 16:33:39 -0000	1.15
+++ Src/jobs.c	30 May 2002 15:12:37 -0000
@@ -55,6 +55,12 @@
 /**/
 mod_export struct job jobtab[MAXJOB];
 
+/* If we have entered a subshell, the original shell's job table. */
+static struct job *oldjobtab;
+
+/* The size of that. */
+static int oldmaxjob;
+
 /* shell timings */
  
 /**/
@@ -612,13 +618,18 @@
 printjob(Job jn, int lng, int synch)
 {
     Process pn;
-    int job = jn - jobtab, len = 9, sig, sflag = 0, llen;
+    int job, len = 9, sig, sflag = 0, llen;
     int conted = 0, lineleng = columns, skip = 0, doputnl = 0;
     FILE *fout = (synch == 2) ? stdout : shout;
 
     if (jn->stat & STAT_NOPRINT)
 	return;
 
+    if (jn < jobtab || jn >= jobtab + MAXJOB)
+	job = jn - oldjobtab;
+    else
+	job = jn - jobtab;
+
     if (lng < 0) {
 	conted = 1;
 	lng = 0;
@@ -655,10 +666,10 @@
 	}
     }
 
-/* print if necessary */
+/* print if necessary: ignore option state on explicit call to `jobs'. */
 
-    if (interact && jobbing && ((jn->stat & STAT_STOPPED) || sflag ||
-				job != thisjob)) {
+    if (((interact && jobbing) || synch == 2) &&
+	((jn->stat & STAT_STOPPED) || sflag ||job != thisjob)) {
 	int len2, fline = 1;
 	Process qn;
 
@@ -681,7 +692,7 @@
 	    if (job != thisjob) {
 		if (fline)
 		    fprintf(fout, "[%ld]  %c ",
-			    (long)(jn - jobtab),
+			    (long)job,
 			    (job == curjob) ? '+'
 			    : (job == prevjob) ? '-' : ' ');
 		else
@@ -956,13 +967,32 @@
 
 /**/
 mod_export void
-clearjobtab(void)
+clearjobtab(int monitor)
 {
     int i;
 
-    for (i = 1; i < MAXJOB; i++)
-	if (jobtab[i].ty)
+    for (i = 1; i < MAXJOB; i++) {
+	if (jobtab[i].ty) {
 	    zfree(jobtab[i].ty, sizeof(struct ttyinfo));
+	    jobtab[i].ty = NULL;
+	}
+	if (monitor) {
+	    /*
+	     * See if there is a jobtable worth saving.
+	     * We never free the saved version; it only happens
+	     * once for each subshell of a shell with job control,
+	     * so doesn't create a leak.
+	     */
+	    if (jobtab[i].stat)
+		oldmaxjob = i;
+	}
+    }
+
+    if (monitor && oldmaxjob) {
+	int sz = oldmaxjob * sizeof(struct job);
+	oldjobtab = (struct job *)zalloc(sz);
+	memcpy(oldjobtab, jobtab, sz);
+    }
 
     memset(jobtab, 0, sizeof(jobtab)); /* zero out table */
 }
@@ -1274,13 +1304,22 @@
 	    firstjob = curjob;
 	} else if (func == BIN_JOBS) {
 	    /* List jobs. */
-	    for (job = 0; job != MAXJOB; job++)
-		if (job != thisjob && jobtab[job].stat) {
+	    struct job *jobptr;
+	    int maxjob;
+	    if (unset(MONITOR) && oldmaxjob) {
+		jobptr = oldjobtab;
+		maxjob = oldmaxjob;
+	    } else {
+		jobptr = jobtab;
+		maxjob = MAXJOB;
+	    }
+	    for (job = 0; job != maxjob; job++, jobptr++)
+		if (job != thisjob && jobptr->stat) {
 		    if ((!ops['r'] && !ops['s']) ||
 			(ops['r'] && ops['s']) ||
-			(ops['r'] && !(jobtab[job].stat & STAT_STOPPED)) ||
-			(ops['s'] && jobtab[job].stat & STAT_STOPPED))
-			printjob(job + jobtab, lng, 2);
+			(ops['r'] && !(jobptr->stat & STAT_STOPPED)) ||
+			(ops['s'] && jobptr->stat & STAT_STOPPED))
+			printjob(jobptr, lng, 2);
 		}
 	    unqueue_signals();
 	    return 0;

-- 
Peter Stephenson <pws@xxxxxxx>                  Software Engineer
CSR Ltd., Science Park, Milton Road,
Cambridge, CB4 0WH, UK                          Tel: +44 (0)1223 392070


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