ml-bounces was applied too soon.  we need a -bounces directory
to catch bounces if we're not going to reply on /dev/null to do it.
for now, just make the -bounces pipeto eat any bounces.  perhaps
something more intelligent could be done later.

Reference: /n/atom/patch/applied2013/mlmgr-bounces
Date: Thu Jul 11 21:45:26 CES 2013
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/upas/ml/mlmgr.c	Thu Jul 11 21:44:27 2013
+++ /sys/src/cmd/upas/ml/mlmgr.c	Thu Jul 11 21:44:28 2013
@@ -1,14 +1,23 @@
 #include "common.h"
 #include "dat.h"
 
-int cflag;
-int aflag;
-int rflag;
+enum {
+	Bounces,
+	Owner,
+	List,
+	Nboxes,
+};
+
+char *suffix[Nboxes] = {
+[Bounces]	"-bounces",
+[Owner]		"-owner",
+[List]		"",
+};
 
 int
-createpipeto(char *alfile, char *user, char *listname, int owner)
+createpipeto(char *alfile, char *user, char *listname, char *dom, int which)
 {
-	char buf[Pathlen];
+	char buf[Pathlen], rflag[64];
 	int fd;
 	Dir *d;
 
@@ -28,11 +37,23 @@
 		fprint(fd, "Couldn't wstat %s: %r\n", buf);
 	free(d);
 
+	if(dom != nil)
+		snprint(rflag, sizeof rflag, "-r%s@%s ", listname, dom);
+	else
+		rflag[0] = 0;
+
 	fprint(fd, "#!/bin/rc\n");
-	if(owner)
+	switch(which){
+	case Owner:
 		fprint(fd, "/bin/upas/mlowner %s %s\n", alfile, listname);
-	else
-		fprint(fd, "/bin/upas/ml %s %s\n", alfile, user);
+		break;
+	case List:
+		fprint(fd, "/bin/upas/ml %s%s %s\n", rflag, alfile, user);
+		break;
+	case Bounces:
+		fprint(fd, "exit ''\n");
+		break;
+	}
 	close(fd);
 
 	return 0;
@@ -49,25 +70,24 @@
 void
 main(int argc, char **argv)
 {
-	char *listname, *addr, alfile[Pathlen], owner[64];
+	char *listname, *dom, *addr, alfile[Pathlen], buf[64], flag[127];
+	int i;
+
 
 	rfork(RFENVG|RFREND);
 
+	memset(flag, 0, sizeof flag);
 	ARGBEGIN{
 	case 'c':
-		cflag = 1;
-		break;
 	case 'r':
-		rflag = 1;
-		break;
 	case 'a':
-		aflag = 1;
+		flag[ARGC()] = 1;
 		break;
 	default:
 		usage();
 	}ARGEND;
 
-	if(aflag + rflag + cflag > 1){
+	if(flag['a'] + flag['r'] + flag['c'] > 1){
 		fprint(2, "%s: -a, -r, and -c are mutually exclusive\n", argv0);
 		exits("usage");
 	}
@@ -76,26 +96,26 @@
 		usage();
 
 	listname = argv[0];
+	if((dom = strchr(listname, '@')) != nil)
+		*dom++ = 0;
 	mboxpathbuf(alfile, sizeof alfile, listname, "address-list");
 
-	if(cflag){
-		snprint(owner, sizeof owner, "%s-owner", listname);
-		if(creatembox(listname, nil) < 0)
-			sysfatal("creating %s's mbox: %r", listname);
-		if(creatembox(owner, nil) < 0)
-			sysfatal("creating %s's mbox: %r", owner);
-		if(createpipeto(alfile, listname, listname, 0) < 0)
-			sysfatal("creating %s's pipeto: %r", owner);
-		if(createpipeto(alfile, owner, listname, 1) < 0)
-			sysfatal("creating %s's pipeto: %r", owner);
+	if(flag['c']){
+		for(i = 0; i < Nboxes; i++){
+			snprint(buf, sizeof buf, "%s%s", listname, suffix[i]);
+			if(creatembox(buf, nil) < 0)
+				sysfatal("creating %s's mbox: %r", buf);
+			if(createpipeto(alfile, buf, listname, dom, i) < 0)
+				sysfatal("creating %s's pipeto: %r", buf);
+		}
 		writeaddr(alfile, "# mlmgr c flag", 0, listname);
-	} else if(rflag){
+	} else if(flag['r']){
 		if(argc != 2)
 			usage();
 		addr = argv[1];
 		writeaddr(alfile, "# mlmgr r flag", 0, listname);
 		writeaddr(alfile, addr, 1, listname);
-	} else if(aflag){
+	} else if(flag['a']){
 		if(argc != 2)
 			usage();
 		addr = argv[1];
--- /sys/man/1/mlmgr	Thu Jul 11 21:44:29 2013
+++ /sys/man/1/mlmgr	Thu Jul 11 21:44:29 2013
@@ -4,8 +4,11 @@
 .SH SYNOPSIS
 .B upas/mlmgr -c
 .I listname
+[
+.RI @ domain
+]
 .PP
-.B upas/mlmgr -ar
+.B upas/mlmgr -[ar]
 .I listname
 .I address
 .PP
@@ -25,10 +28,11 @@
 creates and updates unmoderated mailing lists.
 The
 .B -c
-option creates mail directories for both
-.I listname
-and
+option creates mail directories for
+.IR listname ,
 .IB listname -owner\f1,\fP
+and
+.IB listname -bounces\f1,\fP
 each containing a
 .B pipeto
 file.
@@ -42,10 +46,15 @@
 fields are
 removed from the messages and new ones are added
 directing replies to
-.I listname
+.I listname 
+or
+.IR listname @ domain
 and specifying bulk precedence.  The envelope address for
 error replies is set to
-.BR /dev/null .
+.IR listname -bounces.
+Its
+.B pipefile
+discards error messages.
 .PP
 The mailing list membership is the file
 .BR /mail/box/\fIlistname\fP/address-list .
@@ -118,6 +127,9 @@
 .TP
 .B /mail/box/\fI<listname>\fP-owner
 owner's mailbox directory
+.TP
+.B /mail/box/\fI<listname>\fP-bounces
+mailbox directory handling bounces
 .TP
 .B  /mail/box/\fI<listname>\fP/address-list
 log of mailing list deletions and additions