1 #include "threadimpl.h"
2 
3 enum
4 {
5 	STACK = 8192,
6 };
7 
8 void
9 iointerrupt(Ioproc *io)
10 {
11 	if(!io->inuse)
12 		return;
13 	threadint(io->tid);
14 }
15 
16 static void
17 xioproc(void *a)
18 {
19 	Ioproc *io, *x;
20 	io = a;
21 	/*
22 	 * first recvp acquires the ioproc.
23 	 * second tells us that the data is ready.
24 	 */
25 	for(;;){
26 		while(recv(io->c, &x) == -1)
27 			;
28 		if(x == 0)	/* our cue to leave */
29 			break;
30 		assert(x == io);
31 
32 		/* caller is now committed -- even if interrupted he'll return */
33 		while(recv(io->creply, &x) == -1)
34 			;
35 		if(x == 0)	/* caller backed out */
36 			continue;
37 		assert(x == io);
38 
39 		io->ret = io->op(&io->arg);
40 		if(io->ret < 0)
41 			rerrstr(io->err, sizeof io->err);
42 		while(send(io->creply, &io) == -1)
43 			;
44 		while(recv(io->creply, &x) == -1)
45 			;
46 	}
47 }
48 
49 Ioproc*
50 ioproc(void)
51 {
52 	Ioproc *io;
53 
54 	io = mallocz(sizeof(*io), 1);
55 	if(io == nil)
56 		sysfatal("ioproc malloc: %r");
57 	io->c = chancreate(sizeof(void*), 0);
58 	io->creply = chancreate(sizeof(void*), 0);
59 	io->tid = proccreate(xioproc, io, STACK);
60 	return io;
61 }
62 
63 void
64 closeioproc(Ioproc *io)
65 {
66 	if(io == nil)
67 		return;
68 	iointerrupt(io);
69 	while(send(io->c, 0) == -1)
70 		;
71 	chanfree(io->c);
72 	chanfree(io->creply);
73 	free(io);
74 }