From 2277c5d7bbe1f9595fad512d8f790708473a9bf1 Mon Sep 17 00:00:00 2001
From: rsc <devnull@localhost>
Date: Sun, 21 Mar 2004 04:33:13 +0000
Subject: Small tweaks Lots of new code imported.

---
 src/lib9p/_post.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)
 create mode 100644 src/lib9p/_post.c

(limited to 'src/lib9p/_post.c')

diff --git a/src/lib9p/_post.c b/src/lib9p/_post.c
new file mode 100644
index 00000000..e8313be1
--- /dev/null
+++ b/src/lib9p/_post.c
@@ -0,0 +1,77 @@
+#include <u.h>
+#include <libc.h>
+#include <fcall.h>
+#include <thread.h>
+#include <9p.h>
+#include <auth.h>
+#include "post.h"
+
+Postcrud*
+_post1(Srv *s, char *name, char *mtpt, int flag)
+{
+	Postcrud *p;
+
+	p = emalloc9p(sizeof *p);
+	if(!s->nopipe){
+		if(pipe(p->fd) < 0)
+			sysfatal("pipe: %r");
+		s->infd = s->outfd = p->fd[1];
+		s->srvfd = p->fd[0];
+	}
+	if(name)
+		if(postfd(name, s->srvfd) < 0)
+			sysfatal("postfd %s: %r", name);
+	p->s = s;
+	p->mtpt = mtpt;
+	p->flag = flag;
+	return p;
+}
+
+void
+_post2(void *v)
+{
+	Srv *s;
+
+	s = v;
+	rfork(RFNOTEG);
+	if(!s->leavefdsopen){
+		rendezvous((ulong)s, 0);
+		close(s->srvfd);
+	}
+	srv(s);
+}
+
+void
+_post3(Postcrud *p)
+{
+	/*
+	 * 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(!p->s->leavefdsopen){
+		rfork(RFFDG);
+		rendezvous((ulong)p->s, 0);
+		close(p->s->infd);
+		if(p->s->infd != p->s->outfd)
+			close(p->s->outfd);
+	}
+
+	if(p->mtpt){
+		if(amount(p->s->srvfd, p->mtpt, p->flag, "") == -1)
+			sysfatal("mount %s: %r", p->mtpt);
+	}else
+		close(p->s->srvfd);
+	free(p);
+}
+
-- 
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