jehanne/sys/src/lib/9p/post.c

134 lines
3.4 KiB
C

/*
* This file is part of the UCB release of Plan 9. It is subject to the license
* terms in the LICENSE file found in the top-level directory of this
* distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No
* part of the UCB release of Plan 9, including this file, may be copied,
* modified, propagated, or distributed except according to the terms contained
* in the LICENSE file.
*/
/* Portions of this file are Copyright (C) 2015-2018 Giacomo Tesio <giacomo@tesio.it>
* See /doc/license/gpl-2.0.txt for details about the licensing.
*/
#include <u.h>
#include <lib9.h>
#include <9P2000.h>
#include <thread.h>
#include <9p.h>
#include <auth.h>
static void postproc(void*);
void
_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(name)
if(postfd(name, s->srvfd) < 0)
sysfatal("postfd %s: %r", name);
if(_forker == nil)
sysfatal("no forker");
_forker(postproc, s, RFNAMEG);
/*
* 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){
sys_rfork(RFFDG);
sys_rendezvous(0, 0);
sys_close(s->infd);
if(s->infd != s->outfd)
sys_close(s->outfd);
}
if(mtpt){
if(amount(s->srvfd, mtpt, flag, "") == -1)
sysfatal("mount %s: %r", mtpt);
}else
sys_close(s->srvfd);
}
void
_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(name)
if(postfd(name, s->srvfd) < 0)
sysfatal("postfd %s: %r", name);
if(_forker == nil)
sysfatal("no forker");
_forker(postproc, s, RFNAMEG);
/*
* 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){
sys_rfork(RFFDG);
sys_rendezvous(0, 0);
sys_close(s->infd);
if(s->infd != s->outfd)
sys_close(s->outfd);
}
if(mtpt){
if(sharefd(mtpt, desc, s->srvfd) < 0)
sysfatal("sharefd %s: %r", mtpt);
}else
sys_close(s->srvfd);
}
static void
postproc(void *v)
{
Srv *s;
s = v;
if(!s->leavefdsopen){
sys_rfork(RFNOTEG);
sys_rendezvous(0, 0);
sys_close(s->srvfd);
}
srv(s);
}