PERFORCE change 147836 for review

[Ed Schouten]

http://perforce.freebsd.org/chv.cgi?CH=147836

Change 147836 by ed at ed_dull on 2008/08/19 21:08:04

	Add an unused example of how we could implement a safer TTY
	flushing routine for the input path, which would be very useful
	for utilities like passwd to call, because it guarantees we
	internally zeroise all buffers.
	
	I've not hooked it up to anything yet, but let's hope someone
	(me?) picks this up after the MPSAFE TTY import.
	
	While there, fix some small style(9) issues in tty_*q.c, as I
	didn't know we had the single line of whitespace rule when I
	wrote the code in question.
	
	Requested by:	csjp

Affected files ...

.. //depot/projects/mpsafetty/sys/kern/tty_inq.c#4 edit
.. //depot/projects/mpsafetty/sys/kern/tty_outq.c#4 edit

Differences ...

==== //depot/projects/mpsafetty/sys/kern/tty_inq.c#4 (text+ko) ====

@@ -145,6 +145,7 @@
 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) {
@@ -261,6 +262,7 @@
 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++)
@@ -336,6 +338,7 @@
 void
 ttyinq_canonicalize(struct ttyinq *ti)
 {
+
 	ti->ti_linestart = ti->ti_reprint = ti->ti_end;
 	ti->ti_startblock = ti->ti_reprintblock = ti->ti_lastblock;
 }
@@ -369,12 +372,29 @@
 void
 ttyinq_flush(struct ttyinq *ti)
 {
+
 	ti->ti_begin = 0;
 	ti->ti_linestart = 0;
 	ti->ti_reprint = 0;
 	ti->ti_end = 0;
 }
 
+#if 0
+void
+ttyinq_flush_safe(struct ttyinq *ti)
+{
+	struct ttyinq_block *tib;
+
+	ttyinq_flush(ti);
+
+	/* Zero all data in the input queue to make it more safe */
+	TAILQ_FOREACH(tib, &ti->ti_list, tib_list) {
+		bzero(&tib->tib_quotes, sizeof tib->tib_quotes);
+		bzero(&tib->tib_data, sizeof tib->tib_data);
+	}
+}
+#endif
+
 int
 ttyinq_peekchar(struct ttyinq *ti, char *c, int *quote)
 {
@@ -396,6 +416,7 @@
 void
 ttyinq_unputchar(struct ttyinq *ti)
 {
+
 	MPASS(ti->ti_linestart < ti->ti_end);
 
 	if (--ti->ti_end % TTYINQ_DATASIZE == 0) {
@@ -413,6 +434,7 @@
 void
 ttyinq_reprintpos_set(struct ttyinq *ti)
 {
+
 	ti->ti_reprint = ti->ti_end;
 	ti->ti_reprintblock = ti->ti_lastblock;
 }
@@ -420,6 +442,7 @@
 void
 ttyinq_reprintpos_reset(struct ttyinq *ti)
 {
+
 	ti->ti_reprint = ti->ti_linestart;
 	ti->ti_reprintblock = ti->ti_startblock;
 }
@@ -454,6 +477,7 @@
 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);
 }
@@ -462,6 +486,7 @@
 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);
 }
@@ -469,6 +494,7 @@
 static void
 ttyinq_startup(void *dummy)
 {
+
 	ttyinq_zone = uma_zcreate("ttyinq", sizeof(struct ttyinq_block),
 	    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
 }

==== //depot/projects/mpsafetty/sys/kern/tty_outq.c#4 (text+ko) ====

@@ -70,6 +70,7 @@
 void
 ttyoutq_flush(struct ttyoutq *to)
 {
+
 	to->to_begin = 0;
 	to->to_end = 0;
 }
@@ -197,6 +198,7 @@
 int
 ttyoutq_read_uio(struct ttyoutq *to, struct tty *tp, struct uio *uio)
 {
+
 	while (uio->uio_resid > 0) {
 		int error;
 		struct ttyoutq_block *tob;
@@ -355,6 +357,7 @@
 static void
 ttyoutq_startup(void *dummy)
 {
+
 	ttyoutq_zone = uma_zcreate("ttyoutq", sizeof(struct ttyoutq_block),
 	    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
 }