Hello,

Here is an adjusted patch for upas/fs (and its manpage) that adds an
'finit' control mesage to the mailbox ctl file.  When 'finit' is
written to said file, upas/fs will plumb all the messages back to
faces, resulting in identical behavior to the old faces -i.

diff -r e05e4b6c6546 sys/man/4/upasfs
--- a/sys/man/4/upasfs	Mon Oct 12 02:03:52 2020 +0200
+++ b/sys/man/4/upasfs	Sat Oct 17 22:21:13 2020 -0500
@@ -194,6 +194,12 @@
 Deleting message directories causes the message to be removed from
 the mailbox.
 .PP
+Each mailbox, if the underlying protocol supports it, has a `ctl' file
+under the mailbox directory as well.  For now, the only documented
+message is `finit', which will plumb all existing messages in the
+mailbox to
+.IR faces(1).
+.PP
 The mailbox is scanned and the structure updated
 whenever the mailbox changes.  Message directories are
 not renumbered. The results of the scan are
diff -r e05e4b6c6546 sys/src/cmd/upas/fs/dat.h
--- a/sys/src/cmd/upas/fs/dat.h	Mon Oct 12 02:03:52 2020 +0200
+++ b/sys/src/cmd/upas/fs/dat.h	Sat Oct 17 22:21:13 2020 -0500
@@ -241,6 +241,8 @@
 void		parsebody(Message*, Mailbox*);
 int		strtotm(char*, Tm*);
 char*		lowercase(char*);
+void 		mailplumb(Mailbox*, Message*);
+
 
 char*		sputc(char*, char*, int);
 char*		seappend(char*, char*, char*, int);
diff -r e05e4b6c6546 sys/src/cmd/upas/fs/fs.c
--- a/sys/src/cmd/upas/fs/fs.c	Mon Oct 12 02:03:52 2020 +0200
+++ b/sys/src/cmd/upas/fs/fs.c	Sat Oct 17 22:21:13 2020 -0500
@@ -1194,6 +1194,7 @@
 {
 	char *argvbuf[1024], **argv, file[Pathlen], *err, *v0;
 	int i, t, argc, flags;
+	Message *m;
 
 	t = FILE(f->qid.path);
 	rhdr.count = thdr.count;
@@ -1288,6 +1289,11 @@
 		argc = tokenize(thdr.data, argv, nelem(argvbuf));
 		if(argc == 0)
 			return Ebadctl;
+		if(strcmp(argv[0], "finit") == 0){
+			for(m = f->mb->root->part; m != nil; m = m->next)
+				mailplumb(f->mb, m);
+			return nil;
+		}
 		return f->mb->ctl(f->mb, argc, argv);
 	case Qflags:
 		/*
diff -r e05e4b6c6546 sys/src/cmd/upas/fs/mbox.c
--- a/sys/src/cmd/upas/fs/mbox.c	Mon Oct 12 02:03:52 2020 +0200
+++ b/sys/src/cmd/upas/fs/mbox.c	Sat Oct 17 22:21:13 2020 -0500
@@ -56,7 +56,6 @@
 };
 
 static void delmessage(Mailbox*, Message*);
-static void mailplumb(Mailbox*, Message*);
 
 char*
 syncmbox(Mailbox *mb, int doplumb)
@@ -1544,14 +1543,20 @@
 	return n;
 }
 
-static void
+void
 mailplumb(Mailbox *mb, Message *m)
 {
-	char buf[256], dbuf[SHA1dlen*2 + 1], len[10], date[32], *from, *subject;
+	char buf[256], dbuf[SHA1dlen*2 + 1], len[10], date[32], addr[320], *from, *subject, *bang, *unixfrom;
 	int ai;
 	Plumbmsg p;
 	Plumbattr a[7];
 	static int fd = -1;
+	int didflip;
+
+	if(m == nil){
+		fprint(2, "upasfs mailplumb: nil message\n");
+		return;
+	}
 
 	subject = m->subject;
 	if(subject == nil)
@@ -1572,8 +1577,27 @@
 	if(fd < 0)
 		return;
 
+	/* convert uucp address for faces */
+	didflip = 0;
+	if(from == m->unixfrom){
+		unixfrom = strdup(m->unixfrom);
+		if(unixfrom == nil)
+			return;
+		bang = strchr(unixfrom, '!');
+		*bang++ = '\0';
+		strcpy(addr, bang);
+		strcat(addr, "@");
+		strcat(addr, unixfrom);
+		from = strdup(addr);
+		if(from == nil){
+			free(unixfrom);
+			return;
+		}
+		didflip++;
+	}
+
 	p.src = "mailfs";
-	p.dst = "seemail";
+	p.dst = "notify";
 	p.wdir = "/mail/fs";
 	p.type = "text";
 
@@ -1603,12 +1627,18 @@
 	a[ai].value = date;
 	a[ai-1].next = &a[ai];
 
-	if(m->digest){
-		snprint(dbuf, sizeof dbuf, "%A", m->digest);
-		a[++ai].name = "digest";
-		a[ai].value = dbuf;
-		a[ai-1].next = &a[ai];
-	}
+	if(m->digest == nil)
+		digestmessage(mb, m);
+	snprint(dbuf, sizeof dbuf, "%A", m->digest);
+	
+	a[++ai].name = "digest";
+	a[ai].value = dbuf;
+	a[ai-1].next = &a[ai];
+
+	a[++ai].name = "dst";
+	a[ai].value = "showmail";
+	a[ai-1].next = &a[ai];
+	
 	a[ai].next = nil;
 	p.attr = a;
 	snprint(buf, sizeof buf, "%s/%s/%s",
@@ -1617,6 +1647,11 @@
 	p.data = buf;
 
 	myplumbsend(fd, &p);
+
+	if(didflip != 0){
+		free(unixfrom);
+		free(from);
+	}
 }
 
 /*