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#include <u.h>
#include <libc.h>
#include <thread.h>
#include "ioproc.h"
enum
{
STACK = 32768
};
void
iointerrupt(Ioproc *io)
{
if(!io->inuse)
return;
fprint(2, "bug: cannot iointerrupt %p yet\n", io);
}
static void
xioproc(void *a)
{
Ioproc *io, *x;
threadsetname("ioproc");
io = a;
/*
* first recvp acquires the ioproc.
* second tells us that the data is ready.
*/
for(;;){
while(recv(io->c, &x) == -1)
;
if(x == 0) /* our cue to leave */
break;
assert(x == io);
/* caller is now committed -- even if interrupted he'll return */
while(recv(io->creply, &x) == -1)
;
if(x == 0) /* caller backed out */
continue;
assert(x == io);
io->ret = io->op(&io->arg);
if(io->ret < 0)
rerrstr(io->err, sizeof io->err);
while(send(io->creply, &io) == -1)
;
while(recv(io->creply, &x) == -1)
;
}
}
Ioproc*
ioproc(void)
{
Ioproc *io;
io = mallocz(sizeof(*io), 1);
if(io == nil)
sysfatal("ioproc malloc: %r");
io->c = chancreate(sizeof(void*), 0);
chansetname(io->c, "ioc%p", io->c);
io->creply = chancreate(sizeof(void*), 0);
chansetname(io->creply, "ior%p", io->c);
io->tid = proccreate(xioproc, io, STACK);
return io;
}
void
closeioproc(Ioproc *io)
{
if(io == nil)
return;
iointerrupt(io);
while(send(io->c, 0) == -1)
;
chanfree(io->c);
chanfree(io->creply);
free(io);
}
long
iocall(Ioproc *io, long (*op)(va_list*), ...)
{
char e[ERRMAX];
int ret, inted;
Ioproc *msg;
if(send(io->c, &io) == -1){
werrstr("interrupted");
return -1;
}
assert(!io->inuse);
io->inuse = 1;
io->op = op;
va_start(io->arg, op);
msg = io;
inted = 0;
while(send(io->creply, &msg) == -1){
msg = nil;
inted = 1;
}
if(inted){
werrstr("interrupted");
return -1;
}
/*
* If we get interrupted, we have stick around so that
* the IO proc has someone to talk to. Send it an interrupt
* and try again.
*/
inted = 0;
while(recv(io->creply, nil) == -1){
inted = 1;
iointerrupt(io);
}
USED(inted);
va_end(io->arg);
ret = io->ret;
if(ret < 0)
strecpy(e, e+sizeof e, io->err);
io->inuse = 0;
/* release resources */
while(send(io->creply, &io) == -1)
;
if(ret < 0)
errstr(e, sizeof e);
return ret;
}
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