1 files changed, 497 insertions, 0 deletions

diff --git a/freebsd/sys/kern/tty_inq.c b/freebsd/sys/kern/tty_inq.c
new file mode 100644
index 00000000..0093cb31
--- /dev/null
+++ b/freebsd/sys/kern/tty_inq.c
@@ -0,0 +1,497 @@
+#include <machine/rtems-bsd-kernel-space.h>
+
+/*-
+ * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Portions of this software were developed under sponsorship from Snow
+ * B.V., the Netherlands.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <rtems/bsd/sys/param.h>
+#include <sys/kernel.h>
+#include <rtems/bsd/sys/lock.h>
+#include <sys/queue.h>
+#include <sys/sysctl.h>
+#include <sys/systm.h>
+#include <sys/tty.h>
+#include <sys/uio.h>
+
+#include <vm/uma.h>
+
+/*
+ * TTY input queue buffering.
+ *
+ * Unlike the output queue, the input queue has more features that are
+ * needed to properly implement various features offered by the TTY
+ * interface:
+ *
+ * - Data can be removed from the tail of the queue, which is used to
+ *   implement backspace.
+ * - Once in a while, input has to be `canonicalized'. When ICANON is
+ *   turned on, this will be done after a CR has been inserted.
+ *   Otherwise, it should be done after any character has been inserted.
+ * - The input queue can store one bit per byte, called the quoting bit.
+ *   This bit is used by TTYDISC to make backspace work on quoted
+ *   characters.
+ *
+ * In most cases, there is probably less input than output, so unlike
+ * the outq, we'll stick to 128 byte blocks here.
+ */
+
+static int ttyinq_flush_secure = 1;
+SYSCTL_INT(_kern, OID_AUTO, tty_inq_flush_secure, CTLFLAG_RW,
+	&ttyinq_flush_secure, 0, "Zero buffers while flushing");
+
+#define TTYINQ_QUOTESIZE	(TTYINQ_DATASIZE / BMSIZE)
+#define BMSIZE			32
+#define GETBIT(tib,boff) \
+	((tib)->tib_quotes[(boff) / BMSIZE] & (1 << ((boff) % BMSIZE)))
+#define SETBIT(tib,boff) \
+	((tib)->tib_quotes[(boff) / BMSIZE] |= (1 << ((boff) % BMSIZE)))
+#define CLRBIT(tib,boff) \
+	((tib)->tib_quotes[(boff) / BMSIZE] &= ~(1 << ((boff) % BMSIZE)))
+
+struct ttyinq_block {
+	struct ttyinq_block	*tib_prev;
+	struct ttyinq_block	*tib_next;
+	uint32_t		tib_quotes[TTYINQ_QUOTESIZE];
+	char			tib_data[TTYINQ_DATASIZE];
+};
+
+static uma_zone_t ttyinq_zone;
+
+#define	TTYINQ_INSERT_TAIL(ti, tib) do {				\
+	if (ti->ti_end == 0) {						\
+		tib->tib_prev = NULL;					\
+		tib->tib_next = ti->ti_firstblock;			\
+		ti->ti_firstblock = tib;				\
+	} else {							\
+		tib->tib_prev = ti->ti_lastblock;			\
+		tib->tib_next = ti->ti_lastblock->tib_next;		\
+		ti->ti_lastblock->tib_next = tib;			\
+	}								\
+	if (tib->tib_next != NULL)					\
+		tib->tib_next->tib_prev = tib;				\
+	ti->ti_nblocks++;						\
+} while (0)
+
+#define	TTYINQ_REMOVE_HEAD(ti) do {					\
+	ti->ti_firstblock = ti->ti_firstblock->tib_next;		\
+	if (ti->ti_firstblock != NULL)					\
+		ti->ti_firstblock->tib_prev = NULL;			\
+	ti->ti_nblocks--;						\
+} while (0)
+
+#define	TTYINQ_RECYCLE(ti, tib) do {					\
+	if (ti->ti_quota <= ti->ti_nblocks)				\
+		uma_zfree(ttyinq_zone, tib);				\
+	else								\
+		TTYINQ_INSERT_TAIL(ti, tib);				\
+} while (0)
+
+int
+ttyinq_setsize(struct ttyinq *ti, struct tty *tp, size_t size)
+{
+	struct ttyinq_block *tib;
+
+	ti->ti_quota = howmany(size, TTYINQ_DATASIZE);
+
+	while (ti->ti_quota > ti->ti_nblocks) {
+		/*
+		 * List is getting bigger.
+		 * Add new blocks to the tail of the list.
+		 *
+		 * We must unlock the TTY temporarily, because we need
+		 * to allocate memory. This won't be a problem, because
+		 * in the worst case, another thread ends up here, which
+		 * may cause us to allocate too many blocks, but this
+		 * will be caught by the loop below.
+		 */
+		tty_unlock(tp);
+		tib = uma_zalloc(ttyinq_zone, M_WAITOK);
+		tty_lock(tp);
+
+		if (tty_gone(tp)) {
+			uma_zfree(ttyinq_zone, tib);
+			return (ENXIO);
+		}
+
+		TTYINQ_INSERT_TAIL(ti, tib);
+	}
+	return (0);
+}
+
+void
+ttyinq_free(struct ttyinq *ti)
+{
+	struct ttyinq_block *tib;
+
+	ttyinq_flush(ti);
+	ti->ti_quota = 0;
+
+	while ((tib = ti->ti_firstblock) != NULL) {
+		TTYINQ_REMOVE_HEAD(ti);
+		uma_zfree(ttyinq_zone, tib);
+	}
+
+	MPASS(ti->ti_nblocks == 0);
+}
+
+int
+ttyinq_read_uio(struct ttyinq *ti, struct tty *tp, struct uio *uio,
+    size_t rlen, size_t flen)
+{
+
+	MPASS(rlen <= uio->uio_resid);
+
+	while (rlen > 0) {
+		int error;
+		struct ttyinq_block *tib;
+		size_t cbegin, cend, clen;
+
+		/* See if there still is data. */
+		if (ti->ti_begin == ti->ti_linestart)
+			return (0);
+		tib = ti->ti_firstblock;
+		if (tib == NULL)
+			return (0);
+
+		/*
+		 * The end address should be the lowest of these three:
+		 * - The write pointer
+		 * - The blocksize - we can't read beyond the block
+		 * - The end address if we could perform the full read
+		 */
+		cbegin = ti->ti_begin;
+		cend = MIN(MIN(ti->ti_linestart, ti->ti_begin + rlen),
+		    TTYINQ_DATASIZE);
+		clen = cend - cbegin;
+		MPASS(clen >= flen);
+		rlen -= clen;
+
+		/*
+		 * We can prevent buffering in some cases:
+		 * - We need to read the block until the end.
+		 * - We don't need to read the block until the end, but
+		 *   there is no data beyond it, which allows us to move
+		 *   the write pointer to a new block.
+		 */
+		if (cend == TTYINQ_DATASIZE || cend == ti->ti_end) {
+			/*
+			 * Fast path: zero copy. Remove the first block,
+			 * so we can unlock the TTY temporarily.
+			 */
+			TTYINQ_REMOVE_HEAD(ti);
+			ti->ti_begin = 0;
+
+			/*
+			 * Because we remove the first block, we must
+			 * fix up the block offsets.
+			 */
+#define CORRECT_BLOCK(t) do {			\
+	if (t <= TTYINQ_DATASIZE)		\
+		t = 0;				\
+	else					\
+		t -= TTYINQ_DATASIZE;		\
+} while (0)
+			CORRECT_BLOCK(ti->ti_linestart);
+			CORRECT_BLOCK(ti->ti_reprint);
+			CORRECT_BLOCK(ti->ti_end);
+#undef CORRECT_BLOCK
+
+			/*
+			 * Temporary unlock and copy the data to
+			 * userspace. We may need to flush trailing
+			 * bytes, like EOF characters.
+			 */
+			tty_unlock(tp);
+			error = uiomove(tib->tib_data + cbegin,
+			    clen - flen, uio);
+			tty_lock(tp);
+
+			/* Block can now be readded to the list. */
+			TTYINQ_RECYCLE(ti, tib);
+		} else {
+			char ob[TTYINQ_DATASIZE - 1];
+
+			/*
+			 * Slow path: store data in a temporary buffer.
+			 */
+			memcpy(ob, tib->tib_data + cbegin, clen - flen);
+			ti->ti_begin += clen;
+			MPASS(ti->ti_begin < TTYINQ_DATASIZE);
+
+			/* Temporary unlock and copy the data to userspace. */
+			tty_unlock(tp);
+			error = uiomove(ob, clen - flen, uio);
+			tty_lock(tp);
+		}
+
+		if (error != 0)
+			return (error);
+		if (tty_gone(tp))
+			return (ENXIO);
+	}
+
+	return (0);
+}
+
+static __inline void
+ttyinq_set_quotes(struct ttyinq_block *tib, size_t offset,
+    size_t length, int value)
+{
+
+	if (value) {
+		/* Set the bits. */
+		for (; length > 0; length--, offset++)
+			SETBIT(tib, offset);
+	} else {
+		/* Unset the bits. */
+		for (; length > 0; length--, offset++)
+			CLRBIT(tib, offset);
+	}
+}
+
+size_t
+ttyinq_write(struct ttyinq *ti, const void *buf, size_t nbytes, int quote)
+{
+	const char *cbuf = buf;
+	struct ttyinq_block *tib;
+	unsigned int boff;
+	size_t l;
+
+	while (nbytes > 0) {
+		boff = ti->ti_end % TTYINQ_DATASIZE;
+
+		if (ti->ti_end == 0) {
+			/* First time we're being used or drained. */
+			MPASS(ti->ti_begin == 0);
+			tib = ti->ti_firstblock;
+			if (tib == NULL) {
+				/* Queue has no blocks. */
+				break;
+			}
+			ti->ti_lastblock = tib;
+		} else if (boff == 0) {
+			/* We reached the end of this block on last write. */
+			tib = ti->ti_lastblock->tib_next;
+			if (tib == NULL) {
+				/* We've reached the watermark. */
+				break;
+			}
+			ti->ti_lastblock = tib;
+		} else {
+			tib = ti->ti_lastblock;
+		}
+
+		/* Don't copy more than was requested. */
+		l = MIN(nbytes, TTYINQ_DATASIZE - boff);
+		MPASS(l > 0);
+		memcpy(tib->tib_data + boff, cbuf, l);
+
+		/* Set the quoting bits for the proper region. */
+		ttyinq_set_quotes(tib, boff, l, quote);
+
+		cbuf += l;
+		nbytes -= l;
+		ti->ti_end += l;
+	}
+
+	return (cbuf - (const char *)buf);
+}
+
+int
+ttyinq_write_nofrag(struct ttyinq *ti, const void *buf, size_t nbytes, int quote)
+{
+	size_t ret;
+
+	if (ttyinq_bytesleft(ti) < nbytes)
+		return (-1);
+
+	/* We should always be able to write it back. */
+	ret = ttyinq_write(ti, buf, nbytes, quote);
+	MPASS(ret == nbytes);
+
+	return (0);
+}
+
+void
+ttyinq_canonicalize(struct ttyinq *ti)
+{
+
+	ti->ti_linestart = ti->ti_reprint = ti->ti_end;
+	ti->ti_startblock = ti->ti_reprintblock = ti->ti_lastblock;
+}
+
+size_t
+ttyinq_findchar(struct ttyinq *ti, const char *breakc, size_t maxlen,
+    char *lastc)
+{
+	struct ttyinq_block *tib = ti->ti_firstblock;
+	unsigned int boff = ti->ti_begin;
+	unsigned int bend = MIN(MIN(TTYINQ_DATASIZE, ti->ti_linestart),
+	    ti->ti_begin + maxlen);
+
+	MPASS(maxlen > 0);
+
+	if (tib == NULL)
+		return (0);
+
+	while (boff < bend) {
+		if (strchr(breakc, tib->tib_data[boff]) && !GETBIT(tib, boff)) {
+			*lastc = tib->tib_data[boff];
+			return (boff - ti->ti_begin + 1);
+		}
+		boff++;
+	}
+
+	/* Not found - just process the entire block. */
+	return (bend - ti->ti_begin);
+}
+
+void
+ttyinq_flush(struct ttyinq *ti)
+{
+	struct ttyinq_block *tib;
+
+	ti->ti_begin = 0;
+	ti->ti_linestart = 0;
+	ti->ti_reprint = 0;
+	ti->ti_end = 0;
+
+	/* Zero all data in the input queue to get rid of passwords. */
+	if (ttyinq_flush_secure) {
+		for (tib = ti->ti_firstblock; tib != NULL; tib = tib->tib_next)
+			bzero(&tib->tib_data, sizeof tib->tib_data);
+	}
+}
+
+int
+ttyinq_peekchar(struct ttyinq *ti, char *c, int *quote)
+{
+	unsigned int boff;
+	struct ttyinq_block *tib = ti->ti_lastblock;
+
+	if (ti->ti_linestart == ti->ti_end)
+		return (-1);
+
+	MPASS(ti->ti_end > 0);
+	boff = (ti->ti_end - 1) % TTYINQ_DATASIZE;
+
+	*c = tib->tib_data[boff];
+	*quote = GETBIT(tib, boff);
+
+	return (0);
+}
+
+void
+ttyinq_unputchar(struct ttyinq *ti)
+{
+
+	MPASS(ti->ti_linestart < ti->ti_end);
+
+	if (--ti->ti_end % TTYINQ_DATASIZE == 0) {
+		/* Roll back to the previous block. */
+		ti->ti_lastblock = ti->ti_lastblock->tib_prev;
+		/*
+		 * This can only fail if we are unputchar()'ing the
+		 * first character in the queue.
+		 */
+		MPASS((ti->ti_lastblock == NULL) == (ti->ti_end == 0));
+	}
+}
+
+void
+ttyinq_reprintpos_set(struct ttyinq *ti)
+{
+
+	ti->ti_reprint = ti->ti_end;
+	ti->ti_reprintblock = ti->ti_lastblock;
+}
+
+void
+ttyinq_reprintpos_reset(struct ttyinq *ti)
+{
+
+	ti->ti_reprint = ti->ti_linestart;
+	ti->ti_reprintblock = ti->ti_startblock;
+}
+
+static void
+ttyinq_line_iterate(struct ttyinq *ti,
+    ttyinq_line_iterator_t *iterator, void *data,
+    unsigned int offset, struct ttyinq_block *tib)
+{
+	unsigned int boff;
+
+	/* Use the proper block when we're at the queue head. */
+	if (offset == 0)
+		tib = ti->ti_firstblock;
+
+	/* Iterate all characters and call the iterator function. */
+	for (; offset < ti->ti_end; offset++) {
+		boff = offset % TTYINQ_DATASIZE;
+		MPASS(tib != NULL);
+
+		/* Call back the iterator function. */
+		iterator(data, tib->tib_data[boff], GETBIT(tib, boff));
+
+		/* Last byte iterated - go to the next block. */
+		if (boff == TTYINQ_DATASIZE - 1)
+			tib = tib->tib_next;
+		MPASS(tib != NULL);
+	}
+}
+
+void
+ttyinq_line_iterate_from_linestart(struct ttyinq *ti,
+    ttyinq_line_iterator_t *iterator, void *data)
+{
+
+	ttyinq_line_iterate(ti, iterator, data,
+	    ti->ti_linestart, ti->ti_startblock);
+}
+
+void
+ttyinq_line_iterate_from_reprintpos(struct ttyinq *ti,
+    ttyinq_line_iterator_t *iterator, void *data)
+{
+
+	ttyinq_line_iterate(ti, iterator, data,
+	    ti->ti_reprint, ti->ti_reprintblock);
+}
+
+static void
+ttyinq_startup(void *dummy)
+{
+
+	ttyinq_zone = uma_zcreate("ttyinq", sizeof(struct ttyinq_block),
+	    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
+}
+
+SYSINIT(ttyinq, SI_SUB_DRIVERS, SI_ORDER_FIRST, ttyinq_startup, NULL);