xref: /plan9/sys/src/lib9p/post.c (revision 22a127bbfe4dd304949cc596400de973c0138e31)
19a747e4fSDavid du Colombier #include <u.h>
29a747e4fSDavid du Colombier #include <libc.h>
39a747e4fSDavid du Colombier #include <fcall.h>
49a747e4fSDavid du Colombier #include <thread.h>
59a747e4fSDavid du Colombier #include <9p.h>
6*22a127bbSDavid du Colombier #include <auth.h>
7*22a127bbSDavid du Colombier 
8*22a127bbSDavid du Colombier static void postproc(void*);
99a747e4fSDavid du Colombier 
109a747e4fSDavid du Colombier void
_postmountsrv(Srv * s,char * name,char * mtpt,int flag)11*22a127bbSDavid du Colombier _postmountsrv(Srv *s, char *name, char *mtpt, int flag)
129a747e4fSDavid du Colombier {
13*22a127bbSDavid du Colombier 	int fd[2];
149a747e4fSDavid du Colombier 
15*22a127bbSDavid du Colombier 	if(!s->nopipe){
16*22a127bbSDavid du Colombier 		if(pipe(fd) < 0)
17*22a127bbSDavid du Colombier 			sysfatal("pipe: %r");
18*22a127bbSDavid du Colombier 		s->infd = s->outfd = fd[1];
19*22a127bbSDavid du Colombier 		s->srvfd = fd[0];
209a747e4fSDavid du Colombier 	}
21*22a127bbSDavid du Colombier 	if(name)
22*22a127bbSDavid du Colombier 		if(postfd(name, s->srvfd) < 0)
23*22a127bbSDavid du Colombier 			sysfatal("postfd %s: %r", name);
24*22a127bbSDavid du Colombier 
25*22a127bbSDavid du Colombier 	if(_forker == nil)
26*22a127bbSDavid du Colombier 		sysfatal("no forker");
27*22a127bbSDavid du Colombier 	_forker(postproc, s, RFNAMEG);
28*22a127bbSDavid du Colombier 
29*22a127bbSDavid du Colombier 	/*
30*22a127bbSDavid du Colombier 	 * Normally the server is posting as the last thing it does
31*22a127bbSDavid du Colombier 	 * before exiting, so the correct thing to do is drop into
32*22a127bbSDavid du Colombier 	 * a different fd space and close the 9P server half of the
33*22a127bbSDavid du Colombier 	 * pipe before trying to mount the kernel half.  This way,
34*22a127bbSDavid du Colombier 	 * if the file server dies, we don't have a ref to the 9P server
35*22a127bbSDavid du Colombier 	 * half of the pipe.  Then killing the other procs will drop
36*22a127bbSDavid du Colombier 	 * all the refs on the 9P server half, and the mount will fail.
37*22a127bbSDavid du Colombier 	 * Otherwise the mount hangs forever.
38*22a127bbSDavid du Colombier 	 *
39*22a127bbSDavid du Colombier 	 * Libthread in general and acme win in particular make
40*22a127bbSDavid du Colombier 	 * it hard to make this fd bookkeeping work out properly,
41*22a127bbSDavid du Colombier 	 * so leaveinfdopen is a flag that win sets to opt out of this
42*22a127bbSDavid du Colombier 	 * safety net.
43*22a127bbSDavid du Colombier 	 */
44*22a127bbSDavid du Colombier 	if(!s->leavefdsopen){
45*22a127bbSDavid du Colombier 		rfork(RFFDG);
46*22a127bbSDavid du Colombier 		rendezvous(0, 0);
47*22a127bbSDavid du Colombier 		close(s->infd);
48*22a127bbSDavid du Colombier 		if(s->infd != s->outfd)
49*22a127bbSDavid du Colombier 			close(s->outfd);
509a747e4fSDavid du Colombier 	}
519a747e4fSDavid du Colombier 
52*22a127bbSDavid du Colombier 	if(mtpt){
53*22a127bbSDavid du Colombier 		if(amount(s->srvfd, mtpt, flag, "") == -1)
54*22a127bbSDavid du Colombier 			sysfatal("mount %s: %r", mtpt);
55*22a127bbSDavid du Colombier 	}else
56*22a127bbSDavid du Colombier 		close(s->srvfd);
57*22a127bbSDavid du Colombier }
58*22a127bbSDavid du Colombier 
59*22a127bbSDavid du Colombier static void
postproc(void * v)60*22a127bbSDavid du Colombier postproc(void *v)
61*22a127bbSDavid du Colombier {
62*22a127bbSDavid du Colombier 	Srv *s;
63*22a127bbSDavid du Colombier 
64*22a127bbSDavid du Colombier 	s = v;
65*22a127bbSDavid du Colombier 	if(!s->leavefdsopen){
66*22a127bbSDavid du Colombier 		rfork(RFNOTEG);
67*22a127bbSDavid du Colombier 		rendezvous(0, 0);
68*22a127bbSDavid du Colombier 		close(s->srvfd);
69*22a127bbSDavid du Colombier 	}
70*22a127bbSDavid du Colombier 	srv(s);
71*22a127bbSDavid du Colombier }
72