Function ttyoutq_write

freebsd/kern/tty_outq.c:279–322

}

size_t
ttyoutq_write(struct ttyoutq *to, const void *buf, size_t nbytes)
{
	const char *cbuf = buf;
	struct ttyoutq_block *tob;
	unsigned int boff;
	size_t l;

	while (nbytes > 0) {
		boff = to->to_end % TTYOUTQ_DATASIZE;

		if (to->to_end == 0) {
			/* First time we're being used or drained. */
			MPASS(to->to_begin == 0);
			tob = to->to_firstblock;
			if (tob == NULL) {
				/* Queue has no blocks. */
				break;
			}
			to->to_lastblock = tob;
		} else if (boff == 0) {
			/* We reached the end of this block on last write. */
			tob = to->to_lastblock->tob_next;
			if (tob == NULL) {
				/* We've reached the watermark. */
				break;
			}
			to->to_lastblock = tob;
		} else {
			tob = to->to_lastblock;
		}

		/* Don't copy more than was requested. */
		l = MIN(nbytes, TTYOUTQ_DATASIZE - boff);
		MPASS(l > 0);
		memcpy(tob->tob_data + boff, cbuf, l);

		cbuf += l;
		nbytes -= l;
		to->to_end += l;
	}

	return (cbuf - (const char *)buf);
}

int
ttyoutq_write_nofrag(struct ttyoutq *to, const void *buf, size_t nbytes)