From 225c359beab9e2f17c66e65647b9e0a94f942620 Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@felloff.net>
Date: Sat, 7 Mar 2020 20:19:14 +0100
Subject: [PATCH] lib9p: get rid of Srv.nopipe and Srv.leavefdsopen hacks

it is unclear how Srv.nopipe flag should work inside
postmountserv(). if a server wants to serve on stdio
descriptors, he can just call srv() after initializing
Srv.infd and Srv.outfd.

The Srv.leavefdsopen hack can be removed now that acme
win has been fixed.
---
 sys/include/9p.h      |  2 --
 sys/man/2/9p          |  6 +---
 sys/src/lib9p/post.c  | 82 ++++++++++---------------------------------
 sys/src/lib9p/ramfs.c |  2 +-
 4 files changed, 21 insertions(+), 71 deletions(-)

diff --git a/sys/include/9p.h b/sys/include/9p.h
index c51b1c2b9..53b16ca4a 100644
--- a/sys/include/9p.h
+++ b/sys/include/9p.h
@@ -215,9 +215,7 @@ struct Srv {
 
 	int		infd;
 	int		outfd;
-	int		nopipe;
 	int		srvfd;
-	int		leavefdsopen;	/* magic for acme win */
 	char*	keyspec;
 
 /* below is implementation-specific; don't use */
diff --git a/sys/man/2/9p b/sys/man/2/9p
index f0f50a87e..c1c75fd61 100644
--- a/sys/man/2/9p
+++ b/sys/man/2/9p
@@ -59,7 +59,6 @@ typedef struct Srv {
 	int		infd;
 	int		outfd;
 	int		srvfd;
-	int		nopipe;
 } Srv;
 .fi
 .PP
@@ -175,10 +174,7 @@ are wrappers that create a separate process in which to run
 .IR srv .
 They do the following:
 .IP
-If
-.IB s -> nopipe
-is zero (the common case),
-initialize
+Initialize
 .IB s -> infd
 and
 .IB s -> outfd
diff --git a/sys/src/lib9p/post.c b/sys/src/lib9p/post.c
index 8abddfbd1..0241c3157 100644
--- a/sys/src/lib9p/post.c
+++ b/sys/src/lib9p/post.c
@@ -12,42 +12,22 @@ _postmountsrv(Srv *s, char *name, char *mtpt, int flag)
 {
 	int fd[2];
 
-	if(!s->nopipe){
-		if(pipe(fd) < 0)
-			sysfatal("pipe: %r");
-		s->infd = s->outfd = fd[1];
-		s->srvfd = fd[0];
-	}
+	if(pipe(fd) < 0)
+		sysfatal("pipe: %r");
+	s->infd = s->outfd = fd[1];
+	s->srvfd = fd[0];
+
 	if(name)
 		if(postfd(name, s->srvfd) < 0)
 			sysfatal("postfd %s: %r", name);
 
 	if(_forker == nil)
 		sysfatal("no forker");
-	_forker(postproc, s, RFNAMEG);
+	_forker(postproc, s, RFNAMEG|RFFDG|RFNOTEG);
 
-	/*
-	 * Normally the server is posting as the last thing it does
-	 * before exiting, so the correct thing to do is drop into
-	 * a different fd space and close the 9P server half of the
-	 * pipe before trying to mount the kernel half.  This way,
-	 * if the file server dies, we don't have a ref to the 9P server
-	 * half of the pipe.  Then killing the other procs will drop
-	 * all the refs on the 9P server half, and the mount will fail.
-	 * Otherwise the mount hangs forever.
-	 *
-	 * Libthread in general and acme win in particular make
-	 * it hard to make this fd bookkeeping work out properly,
-	 * so leaveinfdopen is a flag that win sets to opt out of this
-	 * safety net.
-	 */
-	if(!s->leavefdsopen){
-		rfork(RFFDG);
-		rendezvous(0, 0);
-		close(s->infd);
-		if(s->infd != s->outfd)
-			close(s->outfd);
-	}
+	close(s->infd);
+	if(s->infd != s->outfd)
+		close(s->outfd);
 
 	if(mtpt){
 		if(amount(s->srvfd, mtpt, flag, "") == -1)
@@ -61,42 +41,22 @@ _postsharesrv(Srv *s, char *name, char *mtpt, char *desc)
 {
 	int fd[2];
 
-	if(!s->nopipe){
-		if(pipe(fd) < 0)
-			sysfatal("pipe: %r");
-		s->infd = s->outfd = fd[1];
-		s->srvfd = fd[0];
-	}
+	if(pipe(fd) < 0)
+		sysfatal("pipe: %r");
+	s->infd = s->outfd = fd[1];
+	s->srvfd = fd[0];
+
 	if(name)
 		if(postfd(name, s->srvfd) < 0)
 			sysfatal("postfd %s: %r", name);
 
 	if(_forker == nil)
 		sysfatal("no forker");
-	_forker(postproc, s, RFNAMEG);
+	_forker(postproc, s, RFNAMEG|RFFDG|RFNOTEG);
 
-	/*
-	 * Normally the server is posting as the last thing it does
-	 * before exiting, so the correct thing to do is drop into
-	 * a different fd space and close the 9P server half of the
-	 * pipe before trying to mount the kernel half.  This way,
-	 * if the file server dies, we don't have a ref to the 9P server
-	 * half of the pipe.  Then killing the other procs will drop
-	 * all the refs on the 9P server half, and the mount will fail.
-	 * Otherwise the mount hangs forever.
-	 *
-	 * Libthread in general and acme win in particular make
-	 * it hard to make this fd bookkeeping work out properly,
-	 * so leaveinfdopen is a flag that win sets to opt out of this
-	 * safety net.
-	 */
-	if(!s->leavefdsopen){
-		rfork(RFFDG);
-		rendezvous(0, 0);
-		close(s->infd);
-		if(s->infd != s->outfd)
-			close(s->outfd);
-	}
+	close(s->infd);
+	if(s->infd != s->outfd)
+		close(s->outfd);
 
 	if(mtpt){
 		if(sharefd(mtpt, desc, s->srvfd) < 0)
@@ -112,10 +72,6 @@ postproc(void *v)
 	Srv *s;
 
 	s = v;
-	if(!s->leavefdsopen){
-		rfork(RFNOTEG);
-		rendezvous(0, 0);
-		close(s->srvfd);
-	}
+	close(s->srvfd);
 	srv(s);
 }
diff --git a/sys/src/lib9p/ramfs.c b/sys/src/lib9p/ramfs.c
index 13004a4ec..10e9b98be 100644
--- a/sys/src/lib9p/ramfs.c
+++ b/sys/src/lib9p/ramfs.c
@@ -158,7 +158,7 @@ main(int argc, char **argv)
 		usage();
 
 	if(chatty9p)
-		fprint(2, "ramsrv.nopipe %d srvname %s mtpt %s\n", fs.nopipe, srvname, mtpt);
+		fprint(2, "srvname %s mtpt %s\n", srvname, mtpt);
 	if(addr == nil && srvname == nil && mtpt == nil)
 		sysfatal("must specify -a, -s, or -m option");
 	if(addr)