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#include <asm/interrupt.h>
#include <errno.h>
#include <kernel/sched.h>
#include <kernel/serial.h>
#include <kernel/tty.h>
#include <limits.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#define NRTTY \
(sizeof(ttys) / sizeof(struct tty_struct*))
static struct tty_struct *ttys[] = {
NULL,
&tty_rs
};
/* check if the buffer's empty and if so, go to sleep */
static int sleep_while_empty(struct tty_queue *q) {
if(q->pread != q->pwrite)
return 0;
cli();
while(1) {
if(q->pread == q->pwrite)
interruptible_sleep_on(&q->waiting);
/* check again to see if anything was read, or we were interrupted */
if(q->pread == q->pwrite) {
sti();
return -1;
}
sti();
return 0;
}
}
ssize_t tty_read(unsigned tty, void *buf, size_t len) {
size_t i;
char *b = buf;
struct tty_queue *q = &ttys[tty]->rqueue;
if(tty > NRTTY || ttys[tty] == NULL)
return -1;
if(len == 0)
return 0;
if(len > SSIZE_MAX)
len = SSIZE_MAX;
for(i = 0; i < len; i++) {
/* check if the buffer's empty and if so, go to sleep */
if(sleep_while_empty(q) < 0) {
if(i == 0)
return -EINTR;
return i;
}
*b++ = q->buf[q->pread];
q->pread = q->pread + 1 % TTY_BUF_SIZE;
}
return len;
}
void tty_init(void) {
int i;
for(i = 0; i < NRTTY; i++) {
if(!ttys[i])
continue;
memset(&ttys[i]->rqueue, 0, sizeof(struct tty_queue));
memset(&ttys[i]->wqueue, 0, sizeof(struct tty_queue));
ttys[i]->rqueue.pwrite = 1;
ttys[i]->wqueue.pwrite = 1;
if(ttys[i]->init)
ttys[i]->init();
}
}
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