minix/lib/libc/other/asynchio.c

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/* asyn_init(), asyn_read(), asyn_write(), asyn_ioctl(),
* asyn_wait(), asyn_synch(), asyn_close()
* Author: Kees J. Bot
* 26 Jan 1995
* Thise are just stub routines that are call compatible with
* the asynchio(3) library of Minix-vmd. See asynchio.h.
*/
#define nil 0
#define alarm _alarm
#define ioctl _ioctl
#define read _read
#define sigaction _sigaction
#define sigfillset _sigfillset
#define time _time
#define write _write
#include <lib.h>
#include <time.h>
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#include <sys/ioctl.h>
#include <sys/asynchio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#define IO_IDLE 0
#define IO_INPROGRESS 1
#define IO_RESULT 2
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#define OP_NOOP 0
#define OP_READ 1
#define OP_WRITE 2
#define OP_IOCTL 3
static asynchio_t *asyn_current;
void asyn_init(asynchio_t *asyn)
{
asyn->state= IO_IDLE;
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asyn->op= OP_NOOP;
}
static ssize_t operation(int op, asynchio_t *asyn, int fd, int req,
void *data, ssize_t count)
{
switch (asyn->state) {
case IO_INPROGRESS:
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if (asyn_current != asyn && asyn->op != op) abort();
/*FALL THROUGH*/
case IO_IDLE:
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asyn_current= asyn;
asyn->op= op;
asyn->fd= fd;
asyn->req= req;
asyn->data= data;
asyn->count= count;
asyn->state= IO_INPROGRESS;
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errno= EINPROGRESS;
return -1;
case IO_RESULT:
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if (asyn_current != asyn && asyn->op != op) abort();
errno= asyn->errno;
return asyn->count;
}
}
ssize_t asyn_read(asynchio_t *asyn, int fd, void *buf, size_t len)
{
return operation(OP_READ, asyn, fd, 0, buf, len);
}
ssize_t asyn_write(asynchio_t *asyn, int fd, const void *buf, size_t len)
{
return operation(OP_WRITE, asyn, fd, 0, (void *) buf, len);
}
int asyn_ioctl(asynchio_t *asyn, int fd, unsigned long request, void *data)
{
return operation(OP_IOCTL, asyn, fd, request, data, 0);
}
static void time_out(int sig)
{
alarm(1);
}
int asyn_wait(asynchio_t *asyn, int flags, struct timeval *to)
{
time_t now;
unsigned old_timer, new_timer;
struct sigaction old_sa, new_sa;
if (asyn_current != asyn) abort();
if (flags & ASYN_NONBLOCK) abort();
if (asyn->state == IO_RESULT) {
asyn->state= IO_IDLE;
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asyn->op= OP_NOOP;
return 0;
}
if (to != nil) {
now= time(nil);
if (to->tv_sec <= now) { errno= EINTR; return -1; }
old_timer= alarm(0);
new_sa.sa_handler= time_out;
sigfillset(&new_sa.sa_mask);
new_sa.sa_flags= 0;
sigaction(SIGALRM, &new_sa, &old_sa);
new_timer= to->tv_sec - now;
if (new_timer < old_timer) {
new_timer= old_timer;
}
alarm(new_timer);
}
switch (asyn->op) {
case OP_NOOP:
asyn->count= pause();
asyn->errno= errno;
case OP_READ:
asyn->count= read(asyn->fd, asyn->data, asyn->count);
asyn->errno= errno;
break;
case OP_WRITE:
asyn->count= write(asyn->fd, asyn->data, asyn->count);
asyn->errno= errno;
break;
case OP_IOCTL:
asyn->count= ioctl(asyn->fd, asyn->req, asyn->data);
asyn->errno= errno;
break;
}
if (to != nil) {
alarm(0);
sigaction(SIGALRM, &old_sa, (struct sigaction *)0);
alarm(old_timer);
}
if (asyn->count == -1 && asyn->errno == EINTR) {
errno= EINTR;
return -1;
} else {
asyn->state= IO_RESULT;
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return 0;
}
}
int asyn_synch(asynchio_t *asyn, int fd)
{
}
int asyn_close(asynchio_t *asyn, int fd)
{
asyn_init(asyn);
}