1 619085f0 2004-12-25 devnull #include <u.h>
  2 619085f0 2004-12-25 devnull #include <libc.h>
  3 619085f0 2004-12-25 devnull #include <thread.h>
  4 619085f0 2004-12-25 devnull #include "ioproc.h"
  5 619085f0 2004-12-25 devnull 
  6 619085f0 2004-12-25 devnull enum
  7 619085f0 2004-12-25 devnull {
  8 619085f0 2004-12-25 devnull 	STACK = 32768,
  9 619085f0 2004-12-25 devnull };
 10 619085f0 2004-12-25 devnull 
 11 619085f0 2004-12-25 devnull void
 12 619085f0 2004-12-25 devnull iointerrupt(Ioproc *io)
 13 619085f0 2004-12-25 devnull {
 14 619085f0 2004-12-25 devnull 	if(!io->inuse)
 15 619085f0 2004-12-25 devnull 		return;
 16 619085f0 2004-12-25 devnull 	fprint(2, "bug: cannot iointerrupt yet\n");
 17 619085f0 2004-12-25 devnull }
 18 619085f0 2004-12-25 devnull 
 19 619085f0 2004-12-25 devnull static void
 20 619085f0 2004-12-25 devnull xioproc(void *a)
 21 619085f0 2004-12-25 devnull {
 22 619085f0 2004-12-25 devnull 	Ioproc *io, *x;
 23 619085f0 2004-12-25 devnull 	io = a;
 24 619085f0 2004-12-25 devnull 	/*
 25 619085f0 2004-12-25 devnull 	 * first recvp acquires the ioproc.
 26 619085f0 2004-12-25 devnull 	 * second tells us that the data is ready.
 27 619085f0 2004-12-25 devnull 	 */
 28 619085f0 2004-12-25 devnull 	for(;;){
 29 619085f0 2004-12-25 devnull 		while(recv(io->c, &x) == -1)
 30 619085f0 2004-12-25 devnull 			;
 31 619085f0 2004-12-25 devnull 		if(x == 0)	/* our cue to leave */
 32 619085f0 2004-12-25 devnull 			break;
 33 619085f0 2004-12-25 devnull 		assert(x == io);
 34 619085f0 2004-12-25 devnull 
 35 619085f0 2004-12-25 devnull 		/* caller is now committed -- even if interrupted he'll return */
 36 619085f0 2004-12-25 devnull 		while(recv(io->creply, &x) == -1)
 37 619085f0 2004-12-25 devnull 			;
 38 619085f0 2004-12-25 devnull 		if(x == 0)	/* caller backed out */
 39 619085f0 2004-12-25 devnull 			continue;
 40 619085f0 2004-12-25 devnull 		assert(x == io);
 41 619085f0 2004-12-25 devnull 
 42 619085f0 2004-12-25 devnull 		io->ret = io->op(&io->arg);
 43 619085f0 2004-12-25 devnull 		if(io->ret < 0)
 44 619085f0 2004-12-25 devnull 			rerrstr(io->err, sizeof io->err);
 45 619085f0 2004-12-25 devnull 		while(send(io->creply, &io) == -1)
 46 619085f0 2004-12-25 devnull 			;
 47 619085f0 2004-12-25 devnull 		while(recv(io->creply, &x) == -1)
 48 619085f0 2004-12-25 devnull 			;
 49 619085f0 2004-12-25 devnull 	}
 50 619085f0 2004-12-25 devnull }
 51 619085f0 2004-12-25 devnull 
 52 619085f0 2004-12-25 devnull Ioproc*
 53 619085f0 2004-12-25 devnull ioproc(void)
 54 619085f0 2004-12-25 devnull {
 55 619085f0 2004-12-25 devnull 	Ioproc *io;
 56 619085f0 2004-12-25 devnull 
 57 619085f0 2004-12-25 devnull 	io = mallocz(sizeof(*io), 1);
 58 619085f0 2004-12-25 devnull 	if(io == nil)
 59 619085f0 2004-12-25 devnull 		sysfatal("ioproc malloc: %r");
 60 619085f0 2004-12-25 devnull 	io->c = chancreate(sizeof(void*), 0);
 61 619085f0 2004-12-25 devnull 	chansetname(io->c, "ioc%p", io->c);
 62 619085f0 2004-12-25 devnull 	io->creply = chancreate(sizeof(void*), 0);
 63 619085f0 2004-12-25 devnull 	chansetname(io->creply, "ior%p", io->c);
 64 619085f0 2004-12-25 devnull 	io->tid = proccreate(xioproc, io, STACK);
 65 619085f0 2004-12-25 devnull 	return io;
 66 619085f0 2004-12-25 devnull }
 67 619085f0 2004-12-25 devnull 
 68 619085f0 2004-12-25 devnull void
 69 619085f0 2004-12-25 devnull closeioproc(Ioproc *io)
 70 619085f0 2004-12-25 devnull {
 71 619085f0 2004-12-25 devnull 	if(io == nil)
 72 619085f0 2004-12-25 devnull 		return;
 73 619085f0 2004-12-25 devnull 	iointerrupt(io);
 74 619085f0 2004-12-25 devnull 	while(send(io->c, 0) == -1)
 75 619085f0 2004-12-25 devnull 		;
 76 619085f0 2004-12-25 devnull 	chanfree(io->c);
 77 619085f0 2004-12-25 devnull 	chanfree(io->creply);
 78 619085f0 2004-12-25 devnull 	free(io);
 79 619085f0 2004-12-25 devnull }
 80 619085f0 2004-12-25 devnull 
 81 619085f0 2004-12-25 devnull long
 82 619085f0 2004-12-25 devnull iocall(Ioproc *io, long (*op)(va_list*), ...)
 83 619085f0 2004-12-25 devnull {
 84 619085f0 2004-12-25 devnull 	char e[ERRMAX];
 85 619085f0 2004-12-25 devnull 	int ret, inted;
 86 619085f0 2004-12-25 devnull 	Ioproc *msg;
 87 619085f0 2004-12-25 devnull 
 88 619085f0 2004-12-25 devnull 	if(send(io->c, &io) == -1){
 89 619085f0 2004-12-25 devnull 		werrstr("interrupted");
 90 619085f0 2004-12-25 devnull 		return -1;
 91 619085f0 2004-12-25 devnull 	}
 92 619085f0 2004-12-25 devnull 	assert(!io->inuse);
 93 619085f0 2004-12-25 devnull 	io->inuse = 1;
 94 619085f0 2004-12-25 devnull 	io->op = op;
 95 619085f0 2004-12-25 devnull 	va_start(io->arg, op);
 96 619085f0 2004-12-25 devnull 	msg = io;
 97 619085f0 2004-12-25 devnull 	inted = 0;
 98 619085f0 2004-12-25 devnull 	while(send(io->creply, &msg) == -1){
 99 619085f0 2004-12-25 devnull 		msg = nil;
100 619085f0 2004-12-25 devnull 		inted = 1;
101 619085f0 2004-12-25 devnull 	}
102 619085f0 2004-12-25 devnull 	if(inted){
103 619085f0 2004-12-25 devnull 		werrstr("interrupted");
104 619085f0 2004-12-25 devnull 		return -1;
105 619085f0 2004-12-25 devnull 	}
106 619085f0 2004-12-25 devnull 
107 619085f0 2004-12-25 devnull 	/*
108 619085f0 2004-12-25 devnull 	 * If we get interrupted, we have stick around so that
109 619085f0 2004-12-25 devnull 	 * the IO proc has someone to talk to.  Send it an interrupt
110 619085f0 2004-12-25 devnull 	 * and try again.
111 619085f0 2004-12-25 devnull 	 */
112 619085f0 2004-12-25 devnull 	inted = 0;
113 619085f0 2004-12-25 devnull 	while(recv(io->creply, nil) == -1){
114 619085f0 2004-12-25 devnull 		inted = 1;
115 619085f0 2004-12-25 devnull 		iointerrupt(io);
116 619085f0 2004-12-25 devnull 	}
117 619085f0 2004-12-25 devnull 	USED(inted);
118 619085f0 2004-12-25 devnull 	va_end(io->arg);
119 619085f0 2004-12-25 devnull 	ret = io->ret;
120 619085f0 2004-12-25 devnull 	if(ret < 0)
121 619085f0 2004-12-25 devnull 		strecpy(e, e+sizeof e, io->err);
122 619085f0 2004-12-25 devnull 	io->inuse = 0;
123 619085f0 2004-12-25 devnull 
124 619085f0 2004-12-25 devnull 	/* release resources */
125 619085f0 2004-12-25 devnull 	while(send(io->creply, &io) == -1)
126 619085f0 2004-12-25 devnull 		;
127 619085f0 2004-12-25 devnull 	if(ret < 0)
128 619085f0 2004-12-25 devnull 		errstr(e, sizeof e);
129 619085f0 2004-12-25 devnull 	return ret;
130 619085f0 2004-12-25 devnull }