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14249 pseudo-terminal nomenclature should reflect POSIX
Change-Id: Ib4a3cef899ff4c71b09cb0dc6878863c5e8357bc
@@ -25,84 +25,88 @@
/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */
/*
* Copyright 2020 OmniOS Community Edition (OmniOSce) Association.
+ * Copyright 2021 Oxide Computer Company
*/
/*
- * Pseudo Terminal Slave Driver.
+ * PSEUDO-TERMINAL SUBSIDIARY DRIVER (PTS)
*
- * The pseudo-tty subsystem simulates a terminal connection, where the master
- * side represents the terminal and the slave represents the user process's
- * special device end point. The master device is set up as a cloned device
- * where its major device number is the major for the clone device and its minor
- * device number is the major for the ptm driver. There are no nodes in the file
- * system for master devices. The master pseudo driver is opened using the
- * open(2) system call with /dev/ptmx as the device parameter. The clone open
- * finds the next available minor device for the ptm major device.
+ * The pseudo-terminal subsystem simulates a terminal connection, where the
+ * manager side represents the terminal and the subsidiary represents the user
+ * process's special device end point. The manager device is set up as a
+ * cloned device where its major device number is the major for the clone
+ * device and its minor device number is the major for the ptm driver. There
+ * are no nodes in the file system for manager devices. The manager pseudo
+ * driver is opened using the open(2) system call with /dev/ptmx as the device
+ * parameter. The clone open finds the next available minor device for the ptm
+ * major device.
*
- * A master device is available only if it and its corresponding slave device
- * are not already open. When the master device is opened, the corresponding
- * slave device is automatically locked out. Only one open is allowed on a
- * master device. Multiple opens are allowed on the slave device. After both
- * the master and slave have been opened, the user has two file descriptors
- * which are the end points of a full duplex connection composed of two streams
- * which are automatically connected at the master and slave drivers. The user
- * may then push modules onto either side of the stream pair.
+ * A manager device is available only if it and its corresponding subsidiary
+ * device are not already open. When the manager device is opened, the
+ * corresponding subsidiary device is automatically locked out. Only one open
+ * is allowed on a manager device. Multiple opens are allowed on the
+ * subsidiary device. After both the manager and subsidiary have been opened,
+ * the user has two file descriptors which are the end points of a full duplex
+ * connection composed of two streams which are automatically connected at the
+ * manager and subsidiary drivers. The user may then push modules onto either
+ * side of the stream pair.
*
- * The master and slave drivers pass all messages to their adjacent queues.
- * Only the M_FLUSH needs some processing. Because the read queue of one side
- * is connected to the write queue of the other, the FLUSHR flag is changed to
- * the FLUSHW flag and vice versa. When the master device is closed an M_HANGUP
- * message is sent to the slave device which will render the device
- * unusable. The process on the slave side gets the EIO when attempting to write
- * on that stream but it will be able to read any data remaining on the stream
- * head read queue. When all the data has been read, read() returns 0
- * indicating that the stream can no longer be used. On the last close of the
- * slave device, a 0-length message is sent to the master device. When the
- * application on the master side issues a read() or getmsg() and 0 is returned,
- * the user of the master device decides whether to issue a close() that
- * dismantles the pseudo-terminal subsystem. If the master device is not closed,
- * the pseudo-tty subsystem will be available to another user to open the slave
- * device.
+ * The manager and subsidiary drivers pass all messages to their adjacent
+ * queues. Only the M_FLUSH needs some processing. Because the read queue of
+ * one side is connected to the write queue of the other, the FLUSHR flag is
+ * changed to the FLUSHW flag and vice versa. When the manager device is
+ * closed an M_HANGUP message is sent to the subsidiary device which will
+ * render the device unusable. The process on the subsidiary side gets the EIO
+ * when attempting to write on that stream but it will be able to read any data
+ * remaining on the stream head read queue. When all the data has been read,
+ * read() returns 0 indicating that the stream can no longer be used. On the
+ * last close of the subsidiary device, a 0-length message is sent to the
+ * manager device. When the application on the manager side issues a read() or
+ * getmsg() and 0 is returned, the user of the manager device decides whether
+ * to issue a close() that dismantles the pseudo-terminal subsystem. If the
+ * manager device is not closed, the pseudo-tty subsystem will be available to
+ * another user to open the subsidiary device.
*
- * Synchronization:
*
- * All global data synchronization between ptm/pts is done via global
- * ptms_lock mutex which is initialized at system boot time from
- * ptms_initspace (called from space.c).
+ * SYNCHRONIZATION
*
+ * All global data synchronization between ptm/pts is done via global ptms_lock
+ * mutex which is initialized at system boot time from ptms_initspace (called
+ * from space.c).
+ *
* Individual fields of pt_ttys structure (except ptm_rdq, pts_rdq and
* pt_nullmsg) are protected by pt_ttys.pt_lock mutex.
*
* PT_ENTER_READ/PT_ENTER_WRITE are reference counter based read-write locks
* which allow reader locks to be reacquired by the same thread (usual
- * reader/writer locks can't be used for that purpose since it is illegal for
- * a thread to acquire a lock it already holds, even as a reader). The sole
+ * reader/writer locks can't be used for that purpose since it is illegal for a
+ * thread to acquire a lock it already holds, even as a reader). The sole
* purpose of these macros is to guarantee that the peer queue will not
* disappear (due to closing peer) while it is used. It is safe to use
* PT_ENTER_READ/PT_EXIT_READ brackets across calls like putq/putnext (since
* they are not real locks but reference counts).
*
- * PT_ENTER_WRITE/PT_EXIT_WRITE brackets are used ONLY in master/slave
+ * PT_ENTER_WRITE/PT_EXIT_WRITE brackets are used ONLY in manager/subsidiary
* open/close paths to modify ptm_rdq and pts_rdq fields. These fields should
* be set to appropriate queues *after* qprocson() is called during open (to
* prevent peer from accessing the queue with incomplete plumbing) and set to
* NULL before qprocsoff() is called during close.
*
* The pt_nullmsg field is only used in open/close routines and it is also
* protected by PT_ENTER_WRITE/PT_EXIT_WRITE brackets to avoid extra mutex
* holds.
*
- * Lock Ordering:
*
+ * LOCK ORDERING
+ *
* If both ptms_lock and per-pty lock should be held, ptms_lock should always
* be entered first, followed by per-pty lock.
*
* See ptms.h, ptm.c and ptms_conf.c fore more information.
- *
*/
#include <sys/types.h>
#include <sys/param.h>
#include <sys/sysmacros.h>
@@ -133,13 +137,10 @@
static int ptsclose(queue_t *, int, cred_t *);
static int ptswput(queue_t *, mblk_t *);
static int ptsrsrv(queue_t *);
static int ptswsrv(queue_t *);
-/*
- * Slave Stream Pseudo Terminal Module: stream data structure definitions
- */
static struct module_info pts_info = {
0xface,
"pts",
0,
_TTY_BUFSIZ,
@@ -190,13 +191,13 @@
/*
* Module linkage information for the kernel.
*/
static struct modldrv modldrv = {
- &mod_driverops, /* Type of module. This one is a pseudo driver */
- "Slave Stream Pseudo Terminal driver 'pts'",
- &pts_ops, /* driver ops */
+ &mod_driverops,
+ "Pseudo-Terminal Subsidiary Driver",
+ &pts_ops,
};
static struct modlinkage modlinkage = {
MODREV_1,
&modldrv,
@@ -237,11 +238,10 @@
mutex_exit(&ptms_lock);
return (DDI_SUCCESS);
}
-/*ARGSUSED*/
static int
pts_detach(dev_info_t *devi, ddi_detach_cmd_t cmd)
{
if (cmd != DDI_DETACH)
return (DDI_FAILURE);
@@ -250,11 +250,10 @@
* For now, pts cannot be detached.
*/
return (DDI_FAILURE);
}
-/*ARGSUSED*/
static int
pts_devinfo(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg,
void **result)
{
int error;
@@ -278,13 +277,13 @@
return (error);
}
/* ARGSUSED */
/*
- * Open the slave device. Reject a clone open and do not allow the
- * driver to be pushed. If the slave/master pair is locked or if
- * the master is not open, return EACCESS.
+ * Open the subsidiary device. Reject a clone open and do not allow the
+ * driver to be pushed. If the subsidiary/manager pair is locked or if
+ * the manager is not open, return EACCESS.
* Upon success, store the write queue pointer in private data and
* set the PTSOPEN bit in the pt_state field.
*/
static int
ptsopen(
@@ -367,14 +366,14 @@
mutex_exit(&ptms_lock);
return (ENOMEM);
}
/*
- * Slave should send zero-length message to a master when it is
- * closing. If memory is low at that time, master will not detect slave
- * closes, this pty will not be deallocated. So, preallocate this
- * zero-length message block early.
+ * Subsidiary should send zero-length message to a manager when it is
+ * closing. If memory is low at that time, manager will not detect
+ * subsidiary closes, this pty will not be deallocated. So,
+ * preallocate this zero-length message block early.
*/
if ((mp = allocb(0, BPRI_MED)) == NULL) {
mutex_exit(&ptsp->pt_lock);
mutex_exit(&ptms_lock);
freemsg(mop);
@@ -393,13 +392,14 @@
qprocson(rqp);
/*
* After qprocson pts driver is fully plumbed into the stream and can
- * send/receive messages. Setting pts_rdq will allow master side to send
- * messages to the slave. This setting can't occur before qprocson() is
- * finished because slave is not ready to process them.
+ * send/receive messages. Setting pts_rdq will allow manager side to
+ * send messages to the subsidiary. This setting can't occur before
+ * qprocson() is finished because subsidiary is not ready to process
+ * them.
*/
PT_ENTER_WRITE(ptsp);
ptsp->pts_rdq = rqp;
ASSERT(ptsp->pt_nullmsg == NULL);
ptsp->pt_nullmsg = mp;
@@ -420,16 +420,15 @@
return (0);
}
/*
- * Find the address to private data identifying the slave's write
- * queue. Send a 0-length msg up the slave's read queue to designate
- * the master is closing. Uattach the master from the slave by nulling
- * out master's write queue field in private data.
+ * Find the address to private data identifying the subsidiary's write queue.
+ * Send a 0-length msg up the subsidiary's read queue to designate the manager
+ * is closing. Uattach the manager from the subsidiary by nulling out
+ * manager's write queue field in private data.
*/
-/*ARGSUSED1*/
static int
ptsclose(queue_t *rqp, int flag, cred_t *credp)
{
struct pt_ttys *ptsp;
queue_t *wqp;
@@ -448,14 +447,14 @@
}
ptsp = (struct pt_ttys *)rqp->q_ptr;
/*
- * Slave is going to close and doesn't want any new messages coming
- * from the master side, so set pts_rdq to NULL. This should be done
- * before call to qprocsoff() since slave can't process additional
- * messages from the master after qprocsoff is called.
+ * Subsidiary is going to close and doesn't want any new messages
+ * coming from the manager side, so set pts_rdq to NULL. This should
+ * be done before call to qprocsoff() since subsidiary can't process
+ * additional messages from the manager after qprocsoff is called.
*/
PT_ENTER_WRITE(ptsp);
mp = ptsp->pt_nullmsg;
ptsp->pt_nullmsg = NULL;
ptsp->pts_rdq = NULL;
@@ -477,12 +476,12 @@
} else {
freemsg(bp);
}
}
/*
- * qenable master side write queue so that it can flush
- * its messages as slaves's read queue is going away
+ * qenable manager side write queue so that it can flush its messages
+ * as subsidiarys's read queue is going away:
*/
if (ptsp->ptm_rdq) {
if (mp)
putnext(ptsp->ptm_rdq, mp);
else
@@ -501,13 +500,13 @@
return (0);
}
/*
- * The wput procedure will only handle flush messages.
- * All other messages are queued and the write side
- * service procedure sends them off to the master side.
+ * The wput procedure will only handle flush messages. All other messages are
+ * queued and the write side service procedure sends them off to the manager
+ * side.
*/
static int
ptswput(queue_t *qp, mblk_t *mp)
{
struct pt_ttys *ptsp;
@@ -518,13 +517,13 @@
ASSERT(qp->q_ptr);
ptsp = (struct pt_ttys *)qp->q_ptr;
PT_ENTER_READ(ptsp);
if (ptsp->ptm_rdq == NULL) {
- DBG(("in write put proc but no master\n"));
+ DBG(("in write put proc but no manager\n"));
/*
- * NAK ioctl as slave side read queue is gone.
+ * NAK ioctl as subsidiary side read queue is gone.
* Or else free the message.
*/
if (mp->b_datap->db_type == M_IOCTL) {
mp->b_datap->db_type = M_IOCNAK;
freemsg(mp->b_cont);
@@ -538,11 +537,11 @@
if (type >= QPCTL) {
switch (type) {
/*
- * if write queue request, flush slave's write
+ * if write queue request, flush subsidiary's write
* queue and send FLUSHR to ptm. If read queue
* request, send FLUSHR to ptm.
*/
case M_FLUSH:
DBG(("pts got flush request\n"));
@@ -583,13 +582,13 @@
putnext(ptsp->ptm_rdq, nmp);
}
}
}
/*
- * Since the packet module will toss any
- * M_FLUSHES sent to the master's stream head
- * read queue, we simply turn it around here.
+ * Since the packet module will toss any M_FLUSHES sent to the
+ * manager's stream head read queue, we simply turn it around
+ * here.
*/
if (*mp->b_rptr & FLUSHR) {
ASSERT(RD(qp)->q_first == NULL);
DBG(("qreply(qp) turning FLUSHR around\n"));
qreply(qp, mp);
@@ -597,11 +596,11 @@
freemsg(mp);
}
break;
case M_READ:
- /* Caused by ldterm - can not pass to master */
+ /* Caused by ldterm - can not pass to manager */
freemsg(mp);
break;
default:
if (ptsp->ptm_rdq)
@@ -643,13 +642,13 @@
return (0);
}
/* FALLTHROUGH */
default:
/*
- * send other messages to the master
+ * send other messages to the manager
*/
- DBG(("put msg on slave's write queue\n"));
+ DBG(("put msg on subsidiary's write queue\n"));
(void) putq(qp, mp);
break;
}
PT_EXIT_READ(ptsp);
@@ -657,13 +656,12 @@
return (0);
}
/*
- * enable the write side of the master. This triggers the
- * master to send any messages queued on its write side to
- * the read side of this slave.
+ * Enable the write side of the manager. This triggers the manager to send any
+ * messages queued on its write side to the read side of this subsidiary.
*/
static int
ptsrsrv(queue_t *qp)
{
struct pt_ttys *ptsp;
@@ -672,11 +670,11 @@
ASSERT(qp->q_ptr);
ptsp = (struct pt_ttys *)qp->q_ptr;
PT_ENTER_READ(ptsp);
if (ptsp->ptm_rdq == NULL) {
- DBG(("in read srv proc but no master\n"));
+ DBG(("in read srv proc but no manager\n"));
PT_EXIT_READ(ptsp);
return (0);
}
qenable(WR(ptsp->ptm_rdq));
PT_EXIT_READ(ptsp);
@@ -683,14 +681,14 @@
DBG(("leaving ptsrsrv\n"));
return (0);
}
/*
- * If there are messages on this queue that can be sent to
- * master, send them via putnext(). Else, if queued messages
- * cannot be sent, leave them on this queue. If priority
- * messages on this queue, send them to master no matter what.
+ * If there are messages on this queue that can be sent to manager, send them
+ * via putnext(). Otherwise, if queued messages cannot be sent, leave them on
+ * this queue. If priority messages on this queue, send them to manager no
+ * matter what.
*/
static int
ptswsrv(queue_t *qp)
{
struct pt_ttys *ptsp;
@@ -701,16 +699,15 @@
ASSERT(qp->q_ptr);
ptsp = (struct pt_ttys *)qp->q_ptr;
PT_ENTER_READ(ptsp);
if (ptsp->ptm_rdq == NULL) {
- DBG(("in write srv proc but no master\n"));
+ DBG(("in write srv proc but no manager\n"));
/*
- * Free messages on the write queue and send
- * NAK for any M_IOCTL type messages to wakeup
- * the user process waiting for ACK/NAK from
- * the ioctl invocation
+ * Free messages on the write queue and send NAK for any
+ * M_IOCTL type messages to wakeup the user process waiting for
+ * ACK/NAK from the ioctl invocation
*/
while ((mp = getq(qp)) != NULL) {
if (mp->b_datap->db_type == M_IOCTL) {
mp->b_datap->db_type = M_IOCNAK;
freemsg(mp->b_cont);
@@ -724,28 +721,27 @@
} else {
ptm_rdq = ptsp->ptm_rdq;
}
/*
- * while there are messages on this write queue...
+ * While there are messages on this write queue...
*/
while ((mp = getq(qp)) != NULL) {
/*
- * if don't have control message and cannot put
- * msg. on master's read queue, put it back on
- * this queue.
+ * If this is not a control message and we cannot put messages
+ * on the manager's read queue, put it back on this queue.
*/
if (mp->b_datap->db_type <= QPCTL &&
!bcanputnext(ptm_rdq, mp->b_band)) {
DBG(("put msg. back on Q\n"));
(void) putbq(qp, mp);
break;
}
/*
- * else send the message up master's stream
+ * Otherwise, send the message up manager's stream:
*/
- DBG(("send message to master\n"));
+ DBG(("send message to manager\n"));
putnext(ptm_rdq, mp);
}
DBG(("leaving ptswsrv\n"));
PT_EXIT_READ(ptsp);
return (0);