1 #include <u.h>
2 #include <libc.h>
3 #include <fcall.h>
4 #include <thread.h>
5 #include <9p.h>
6 #include <auth.h>
7 #include "post.h"
8 
9 Postcrud*
10 _post1(Srv *s, char *name, char *mtpt, int flag)
11 {
12 	Postcrud *p;
13 
14 	p = emalloc9p(sizeof *p);
15 	if(!s->nopipe){
16 		if(pipe(p->fd) < 0)
17 			sysfatal("pipe: %r");
18 		s->infd = s->outfd = p->fd[1];
19 		s->srvfd = p->fd[0];
20 	}
21 	if(name)
22 		if(postfd(name, s->srvfd) < 0)
23 			sysfatal("postfd %s: %r", name);
24 	p->s = s;
25 	p->mtpt = mtpt;
26 	p->flag = flag;
27 	return p;
28 }
29 
30 void
31 _post2(void *v)
32 {
33 	Srv *s;
34 
35 	s = v;
36 	if(!s->leavefdsopen){
37 		rfork(RFNOTEG);
38 		rendezvous((ulong)s, 0);
39 		close(s->srvfd);
40 	}
41 	srv(s);
42 }
43 
44 void
45 _post3(Postcrud *p)
46 {
47 	/*
48 	 * Normally the server is posting as the last thing it does
49 	 * before exiting, so the correct thing to do is drop into
50 	 * a different fd space and close the 9P server half of the
51 	 * pipe before trying to mount the kernel half.  This way,
52 	 * if the file server dies, we don't have a ref to the 9P server
53 	 * half of the pipe.  Then killing the other procs will drop
54 	 * all the refs on the 9P server half, and the mount will fail.
55 	 * Otherwise the mount hangs forever.
56 	 *
57 	 * Libthread in general and acme win in particular make
58 	 * it hard to make this fd bookkeeping work out properly,
59 	 * so leaveinfdopen is a flag that win sets to opt out of this
60 	 * safety net.
61 	 */
62 	if(!p->s->leavefdsopen){
63 		rfork(RFFDG);
64 		rendezvous((ulong)p->s, 0);
65 		close(p->s->infd);
66 		if(p->s->infd != p->s->outfd)
67 			close(p->s->outfd);
68 	}
69 
70 	if(p->mtpt){
71 		if(amount(p->s->srvfd, p->mtpt, p->flag, "") == -1)
72 			sysfatal("mount %s: %r", p->mtpt);
73 	}else
74 		close(p->s->srvfd);
75 	free(p);
76 }
77