bobvan (09/23/82)
The line turn around scheme I described recently in net.unix-wizards has
generated enough interest that I feel justified in posting diffs to
net.sources. First, I'll give a brief English description of the changes
and then a diff -c. Don't let the size of the diff -c scare you, the changes
really are trivial.
In my original note, I expressed some nervousness about having the 128 bit
set in t_dev. Since then, several sites have said that they have been
using the same or similar schemes for many months without problems.
Changes to dz.c for line turn around:
1) Strip the 128 bit from existing references to minor(dev)
2) In dzopen(dev, flag)
a) Copy dev into t_dev
b) Sleep if in use outgoing and incoming open
c) Fail open if in use incoming and outgoing open
d) Sleep on t_state instead of t_rawq
3) In dzclose()
a) Turn off carrier if was open outgoing
b) Wakeup processes sleeping on t_state
c) Knock bit off of t_dev (paranoia)
4) In dzscan()
a) Wakeup on t_state, not t_rawq as before
b) Wakeup when carrier drops, as well as when it comes up
----------------------------------------
*** dz.old.c Mon Aug 31 03:53:36 1981
--- dz.c Thu Sep 16 07:51:33 1982
***************
*** 6,11
* DZ-11 Driver
*
* This driver mimics dh.c; see it for explanation of common code.
*/
#include "bk.h"
#include "../h/param.h"
--- 6,16 -----
* DZ-11 Driver
*
* This driver mimics dh.c; see it for explanation of common code.
+ *
+ * Line turnaround added 9/1/82, RAV, based on work by dove@mit-mc.
+ * In a nutshell, outgoing inodes (/dev/cul?) have 128 bit set in
+ * the minor number. Minor number is copied into t_dev to record
+ * the "direction" the line is open in.
*/
#include "bk.h"
#include "../h/param.h"
***************
*** 62,67
/* Flags for modem-control */
#define DZ_ON 1
#define DZ_OFF 0
int dzstart(), dzxint(), dzdma();
int ttrstrt();
--- 67,74 -----
/* Flags for modem-control */
#define DZ_ON 1
#define DZ_OFF 0
+
+ #define OUTGOING(dev) ((dev&0200)!=0)
int dzstart(), dzxint(), dzdma();
int ttrstrt();
***************
*** 145,151
register struct tty *tp;
register int unit;
! unit = minor(dev);
if (unit >= dz_cnt || dzpdma[unit].p_addr == 0) {
u.u_error = ENXIO;
return;
--- 152,158 -----
register struct tty *tp;
register int unit;
! unit = minor(dev)&0177;
if (unit >= dz_cnt || dzpdma[unit].p_addr == 0) {
u.u_error = ENXIO;
return;
***************
*** 165,171
u.u_error = EBUSY;
return;
}
- dzmodem(unit, DZ_ON);
(void) spl5();
while ((tp->t_state & CARR_ON) == 0) {
tp->t_state |= WOPEN;
--- 172,177 -----
u.u_error = EBUSY;
return;
}
(void) spl5();
if ((tp->t_state&ISOPEN)==0 && OUTGOING(dev))
tp->t_dev = dev;
***************
*** 167,175
}
dzmodem(unit, DZ_ON);
(void) spl5();
! while ((tp->t_state & CARR_ON) == 0) {
! tp->t_state |= WOPEN;
! sleep((caddr_t)&tp->t_rawq, TTIPRI);
}
(void) spl0();
(*linesw[tp->t_line].l_open)(dev, tp);
--- 173,188 -----
return;
}
(void) spl5();
! if ((tp->t_state&ISOPEN)==0 && OUTGOING(dev))
! tp->t_dev = dev;
! dzmodem(unit, DZ_ON);
! while ((tp->t_state & CARR_ON) == 0
! || (OUTGOING(tp->t_dev) && !OUTGOING(dev))) {
! if ((tp->t_state&ISOPEN) == 0) {
! tp->t_state |= WOPEN;
! dzmodem(unit, DZ_ON);
! }
! sleep((caddr_t)&tp->t_state, TTIPRI);
}
if (!OUTGOING(tp->t_dev) && OUTGOING(dev)) {
u.u_error = EBUSY;
***************
*** 171,176
tp->t_state |= WOPEN;
sleep((caddr_t)&tp->t_rawq, TTIPRI);
}
(void) spl0();
(*linesw[tp->t_line].l_open)(dev, tp);
}
--- 184,193 -----
}
sleep((caddr_t)&tp->t_state, TTIPRI);
}
+ if (!OUTGOING(tp->t_dev) && OUTGOING(dev)) {
+ u.u_error = EBUSY;
+ return;
+ }
(void) spl0();
(*linesw[tp->t_line].l_open)(dev, tp);
}
***************
*** 181,186
{
register struct tty *tp;
register int unit;
int dz;
unit = minor(dev);
--- 198,204 -----
{
register struct tty *tp;
register int unit;
+ int s;
int dz;
unit = minor(dev)&0177;
***************
*** 183,189
register int unit;
int dz;
! unit = minor(dev);
dz = unit >> 3;
tp = &dz_tty[unit];
(*linesw[tp->t_line].l_close)(tp);
--- 201,207 -----
int s;
int dz;
! unit = minor(dev)&0177;
dz = unit >> 3;
tp = &dz_tty[unit];
(*linesw[tp->t_line].l_close)(tp);
***************
*** 189,195
(*linesw[tp->t_line].l_close)(tp);
((struct pdma *)(tp->t_addr))->p_addr->dzbrk =
(dz_brk[dz] &= ~(1 << (unit&07)));
! if (tp->t_state & HUPCLS)
dzmodem(unit, DZ_OFF);
ttyclose(tp);
}
--- 207,213 -----
(*linesw[tp->t_line].l_close)(tp);
((struct pdma *)(tp->t_addr))->p_addr->dzbrk =
(dz_brk[dz] &= ~(1 << (unit&07)));
! if (tp->t_state & HUPCLS || OUTGOING(dev))
dzmodem(unit, DZ_OFF);
ttyclose(tp);
s = spl5();
***************
*** 192,197
if (tp->t_state & HUPCLS)
dzmodem(unit, DZ_OFF);
ttyclose(tp);
}
dzread(dev)
--- 210,221 -----
if (tp->t_state & HUPCLS || OUTGOING(dev))
dzmodem(unit, DZ_OFF);
ttyclose(tp);
+ s = spl5();
+ if (OUTGOING(tp->t_dev) && OUTGOING(dev)) {
+ tp->t_dev &= ~0200;
+ wakeup((caddr_t)&tp->t_state);
+ }
+ splx(s);
}
dzread(dev)
***************
*** 199,205
{
register struct tty *tp;
! tp = &dz_tty[minor(dev)];
(*linesw[tp->t_line].l_read)(tp);
}
--- 223,229 -----
{
register struct tty *tp;
! tp = &dz_tty[minor(dev)&0177];
(*linesw[tp->t_line].l_read)(tp);
}
***************
*** 208,214
{
register struct tty *tp;
! tp = &dz_tty[minor(dev)];
(*linesw[tp->t_line].l_write)(tp);
}
--- 232,238 -----
{
register struct tty *tp;
! tp = &dz_tty[minor(dev)&0177];
(*linesw[tp->t_line].l_write)(tp);
}
***************
*** 265,271
caddr_t addr;
{
register struct tty *tp;
! register int unit = minor(dev);
register int dz = unit >> 3;
tp = &dz_tty[unit];
--- 289,295 -----
caddr_t addr;
{
register struct tty *tp;
! register int unit = minor(dev)&0177;
register int dz = unit >> 3;
tp = &dz_tty[unit];
***************
*** 436,442
if ((dzsoftCAR[i>>3]&bit) || (dzaddr->dzmsr&bit)) {
/* carrier present */
if ((tp->t_state & CARR_ON) == 0) {
! wakeup((caddr_t)&tp->t_rawq);
tp->t_state |= CARR_ON;
}
} else {
--- 460,466 -----
if ((dzsoftCAR[i>>3]&bit) || (dzaddr->dzmsr&bit)) {
/* carrier present */
if ((tp->t_state & CARR_ON) == 0) {
! wakeup((caddr_t)&tp->t_state);
tp->t_state |= CARR_ON;
}
} else {
***************
*** 443,448
if ((tp->t_state&CARR_ON) &&
(tp->t_local&LNOHANG)==0) {
/* carrier lost */
if (tp->t_state&ISOPEN) {
gsignal(tp->t_pgrp, SIGHUP);
gsignal(tp->t_pgrp, SIGCONT);
--- 467,473 -----
if ((tp->t_state&CARR_ON) &&
(tp->t_local&LNOHANG)==0) {
/* carrier lost */
+ wakeup((caddr_t)&tp->t_state);
if (tp->t_state&ISOPEN) {
gsignal(tp->t_pgrp, SIGHUP);
gsignal(tp->t_pgrp, SIGCONT);
----------------------------------------
Bob Van Valzah
(...!decvax!ittvax!tpdcvax!bobvan)