From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org
X-Spam-Level: 
X-Spam-Status: No, score=0.2 required=5.0 tests=DKIM_INVALID,DKIM_SIGNED
	autolearn=no autolearn_force=no version=3.4.4
Received: (qmail 27845 invoked from network); 7 Sep 2021 18:19:31 -0000
Received: from 4ess.inri.net (216.126.196.42)
  by inbox.vuxu.org with ESMTPUTF8; 7 Sep 2021 18:19:31 -0000
Received: from wopr.sciops.net ([216.126.196.60]) by 4ess; Tue Sep  7 13:46:51 -0400 2021
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sciops.net; s=20210706;
	t=1631036801;
	h=from:from:reply-to:subject:subject:date:date:message-id:message-id:
	 to:to:cc:mime-version:mime-version:content-type:content-type:
	 content-transfer-encoding:content-transfer-encoding;
	bh=QMGBhzkYhj/AMnsr7c023awsbB9GQO9h0unsI499SHo=;
	b=NMskYp0rBHmRLOUjerN/qhbud1iQjE51OaoM5d07A7pPo61MSstvHy0iW15Jw2H5lyvJI9
	A3nid2Q3AHObLl84exs/FqT6SXGYbABtmTarx3g9jR7oln7tw6R09s6oZsSQk8V3q1nk2y
	1UlZyoFFRS5ugvY86DjHAgHySPQGnk0=
Received: 
	by wopr.sciops.net (OpenSMTPD) with ESMTPSA id 960c6e79 (TLSv1.2:ECDHE-RSA-CHACHA20-POLY1305:256:NO)
	for <9front@9front.org>;
	Tue, 7 Sep 2021 10:46:40 -0700 (PDT)
Message-ID: <AA80538B10AD48D91BEC0531F9C0FE64@wopr.sciops.net>
Date: Tue, 07 Sep 2021 19:46:39 +0200
From: qwx@sciops.net
To: 9front@9front.org
MIME-Version: 1.0
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
List-ID: <9front.9front.org>
List-Help: <http://lists.9front.org>
X-Glyph: ➈
X-Bullshit: proven lifecycle proxy strategy 
Subject: [9front] plumber: remove $plumbsrv, add optional srvname, usage check
Reply-To: 9front@9front.org
Precedence: bulk

Plumber both posts a service to /srv and sets a $plumbsrv environment
variable.  Our libplumb no longer uses $plumbsrv and nothing else
does.  It's a silly hack;  rc doesn't update /env immediately, and
scripts, which for instance set up subrios, cannot rely on it to
clean up the plumber at the end.

Instead, add the option to specify a srvname, actually check for some
common errors and print a usage string.

Thanks to Ori for input and a preliminary patch.  Thoughts?

Cheers,
qwx

diff 87a823332f9eaa4ff1e72f8524f6e59d1cc4f407 uncommitted
--- a//sys/man/4/plumber
+++ b//sys/man/4/plumber
@@ -6,6 +6,9 @@
 [
 .B -p
 .I plumbing
+] [
+.B -s
+.I srvname
 ]
 .SH DESCRIPTION
 The
@@ -31,11 +34,17 @@
 and a set of output
 .I ports
 for dispatching messages to applications.
+.PP
 The service is also published as a
 .IR srv (4)
-file, named in
-.BR $plumbsrv ,
+file,
+.IR srvname ,
 for mounting elsewhere.
+By default, its name is a dot-separated concatenation
+of the program's name and a process id.
+A different one can be specified via the
+.B -s
+option.
 .PP
 Programs use
 .B write
--- a//sys/src/cmd/plumb/fsys.c
+++ b//sys/src/cmd/plumb/fsys.c
@@ -218,9 +218,10 @@
 	clock = getclock();
 	if(cexecpipe(&mntfd, &srvfd) < 0)
 		error("can't create pipe: %r");
-	sprint(srvfile, "/srv/plumb.%s.%d", user, getpid());
-	if(putenv("plumbsrv", srvfile) < 0)
-		error("can't write $plumbsrv: %r");
+	if(srvname == nil)
+		snprint(srvfile, sizeof(srvfile), "/srv/plumb.%s.%d", user, getpid());
+	else
+		snprint(srvfile, sizeof(srvfile), "/srv/%s", srvname);
 	fd = create(srvfile, OWRITE|OCEXEC|ORCLOSE, 0600);
 	if(fd < 0)
 		error("can't create /srv file: %r");
--- a//sys/src/cmd/plumb/plumber.c
+++ b//sys/src/cmd/plumb/plumber.c
@@ -15,6 +15,7 @@
 int	printerrors=1;
 jmp_buf	parsejmp;
 char	*lasterror;
+char	*srvname;
 
 void
 makeports(Ruleset *rules[])
@@ -38,6 +39,13 @@
 }
 
 void
+usage(void)
+{
+	fprint(2, "usage: %s [-p plumbfile] [-s srvname]\n", argv0);
+	exits("usage");
+}
+
+void
 threadmain(int argc, char *argv[])
 {
 	char buf[512];
@@ -48,7 +56,13 @@
 
 	ARGBEGIN{
 	case 'p':
-		plumbfile = ARGF();
+		plumbfile = EARGF(usage());
+		break;
+	case 's':
+		srvname = EARGF(usage());
+		break;
+	default:
+		usage();
 		break;
 	}ARGEND
 
--- a//sys/src/cmd/plumb/plumber.h
+++ b//sys/src/cmd/plumb/plumber.h
@@ -92,3 +92,4 @@
 char		*lasterror;
 char		**ports;
 int		nports;
+char		*srvname;