/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright 2006 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */ /* All Rights Reserved */ #pragma ident "%Z%%M% %I% %E% SMI" /* * Pseudo Terminal Master Driver. * * 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. * * 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. * * 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. * * If O_NONBLOCK or O_NDELAY is set, read on the master side returns -1 with * errno set to EAGAIN if no data is available, and write returns -1 with errno * set to EAGAIN if there is internal flow control. * * IOCTLS: * * ISPTM: determines whether the file descriptor is that of an open master * device. Return code of zero indicates that the file descriptor * represents master device. * * UNLKPT: unlocks the master and slave devices. It returns 0 on success. On * failure, the errno is set to EINVAL indicating that the master * device is not open. * * ZONEPT: sets the zone membership of the associated pts device. * * GRPPT: sets the group owner of the associated pts 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). * * 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 * 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 * 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: * * 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, pts.c and ptms_conf.c for more information. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef DEBUG int ptm_debug = 0; #define DBG(a) if (ptm_debug) cmn_err(CE_NOTE, a) #else #define DBG(a) #endif static int ptmopen(queue_t *, dev_t *, int, int, cred_t *); static int ptmclose(queue_t *, int, cred_t *); static void ptmwput(queue_t *, mblk_t *); static void ptmrsrv(queue_t *); static void ptmwsrv(queue_t *); /* * Master Stream Pseudo Terminal Module: stream data structure definitions */ static struct module_info ptm_info = { 0xdead, "ptm", 0, 512, 512, 128 }; static struct qinit ptmrint = { NULL, (int (*)()) ptmrsrv, ptmopen, ptmclose, NULL, &ptm_info, NULL }; static struct qinit ptmwint = { (int (*)()) ptmwput, (int (*)()) ptmwsrv, NULL, NULL, NULL, &ptm_info, NULL }; static struct streamtab ptminfo = { &ptmrint, &ptmwint, NULL, NULL }; static int ptm_attach(dev_info_t *, ddi_attach_cmd_t); static int ptm_detach(dev_info_t *, ddi_detach_cmd_t); static int ptm_devinfo(dev_info_t *, ddi_info_cmd_t, void *, void **); static dev_info_t *ptm_dip; /* private devinfo pointer */ /* * this will define (struct cb_ops cb_ptm_ops) and (struct dev_ops ptm_ops) */ DDI_DEFINE_STREAM_OPS(ptm_ops, nulldev, nulldev, ptm_attach, ptm_detach, nodev, ptm_devinfo, D_MP, &ptminfo); /* * Module linkage information for the kernel. */ static struct modldrv modldrv = { &mod_driverops, /* Type of module. This one is a pseudo driver */ "Master streams driver 'ptm' %I%", &ptm_ops, /* driver ops */ }; static struct modlinkage modlinkage = { MODREV_1, &modldrv, NULL }; int _init(void) { int rc; if ((rc = mod_install(&modlinkage)) == 0) ptms_init(); return (rc); } int _fini(void) { return (mod_remove(&modlinkage)); } int _info(struct modinfo *modinfop) { return (mod_info(&modlinkage, modinfop)); } static int ptm_attach(dev_info_t *devi, ddi_attach_cmd_t cmd) { if (cmd != DDI_ATTACH) return (DDI_FAILURE); if (ddi_create_minor_node(devi, "ptmajor", S_IFCHR, 0, DDI_PSEUDO, NULL) == DDI_FAILURE) { ddi_remove_minor_node(devi, NULL); return (DDI_FAILURE); } if (ddi_create_minor_node(devi, "ptmx", S_IFCHR, 0, DDI_PSEUDO, CLONE_DEV) == DDI_FAILURE) { ddi_remove_minor_node(devi, NULL); return (DDI_FAILURE); } ptm_dip = devi; return (DDI_SUCCESS); } static int ptm_detach(dev_info_t *devi, ddi_detach_cmd_t cmd) { if (cmd != DDI_DETACH) return (DDI_FAILURE); ddi_remove_minor_node(devi, NULL); return (DDI_SUCCESS); } /*ARGSUSED*/ static int ptm_devinfo(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result) { int error; switch (infocmd) { case DDI_INFO_DEVT2DEVINFO: if (ptm_dip == NULL) { error = DDI_FAILURE; } else { *result = (void *)ptm_dip; error = DDI_SUCCESS; } break; case DDI_INFO_DEVT2INSTANCE: *result = (void *)0; error = DDI_SUCCESS; break; default: error = DDI_FAILURE; } return (error); } /* ARGSUSED */ /* * Open a minor of the master device. Store the write queue pointer and set the * pt_state field to (PTMOPEN | PTLOCK). * This code will work properly with both clone opens and direct opens of the * master device. */ static int ptmopen( queue_t *rqp, /* pointer to the read side queue */ dev_t *devp, /* pointer to stream tail's dev */ int oflag, /* the user open(2) supplied flags */ int sflag, /* open state flag */ cred_t *credp) /* credentials */ { struct pt_ttys *ptmp; mblk_t *mop; /* ptr to a setopts message block */ struct stroptions *sop; minor_t dminor = getminor(*devp); /* Allow reopen */ if (rqp->q_ptr != NULL) return (0); if (sflag & MODOPEN) return (ENXIO); if (!(sflag & CLONEOPEN) && dminor != 0) { /* * This is a direct open to specific master device through an * artificially created entry with specific minor in * /dev/directory. Such behavior is not supported. */ return (ENXIO); } /* * The master open requires that the slave be attached * before it returns so that attempts to open the slave will * succeeed */ if (ptms_attach_slave() != 0) { return (ENXIO); } mop = allocb(sizeof (struct stroptions), BPRI_MED); if (mop == NULL) { DDBG("ptmopen(): mop allocation failed\n", 0); return (ENOMEM); } if ((ptmp = pt_ttys_alloc()) == NULL) { DDBG("ptmopen(): pty allocation failed\n", 0); freemsg(mop); return (ENOMEM); } dminor = ptmp->pt_minor; DDBGP("ptmopen(): allocated ptmp %p\n", (uintptr_t)ptmp); DDBG("ptmopen(): allocated minor %d\n", dminor); WR(rqp)->q_ptr = rqp->q_ptr = ptmp; qprocson(rqp); /* Allow slave to send messages to master */ PT_ENTER_WRITE(ptmp); ptmp->ptm_rdq = rqp; PT_EXIT_WRITE(ptmp); /* * set up hi/lo water marks on stream head read queue * and add controlling tty if not set */ mop->b_datap->db_type = M_SETOPTS; mop->b_wptr += sizeof (struct stroptions); sop = (struct stroptions *)mop->b_rptr; if (oflag & FNOCTTY) sop->so_flags = SO_HIWAT | SO_LOWAT; else sop->so_flags = SO_HIWAT | SO_LOWAT | SO_ISTTY; sop->so_hiwat = 512; sop->so_lowat = 256; putnext(rqp, mop); /* * The input, devp, is a major device number, the output is put * into the same parm as a major,minor pair. */ *devp = makedevice(getmajor(*devp), dminor); return (0); } /* * Find the address to private data identifying the slave's write queue. * Send a hang-up message up the slave's read queue to designate the * master/slave pair is tearing down. Uattach the master and slave by * nulling out the write queue fields in the private data structure. * Finally, unlock the master/slave pair and mark the master as closed. */ /*ARGSUSED1*/ static int ptmclose(queue_t *rqp, int flag, cred_t *credp) { struct pt_ttys *ptmp; queue_t *pts_rdq; ASSERT(rqp->q_ptr); ptmp = (struct pt_ttys *)rqp->q_ptr; PT_ENTER_READ(ptmp); if (ptmp->pts_rdq) { pts_rdq = ptmp->pts_rdq; if (pts_rdq->q_next) { DBG(("send hangup message to slave\n")); (void) putnextctl(pts_rdq, M_HANGUP); } } PT_EXIT_READ(ptmp); /* * ptm_rdq should be cleared before call to qprocsoff() to prevent pts * write procedure to attempt using ptm_rdq after qprocsoff. */ PT_ENTER_WRITE(ptmp); ptmp->ptm_rdq = NULL; freemsg(ptmp->pt_nullmsg); ptmp->pt_nullmsg = NULL; /* * qenable slave side write queue so that it can flush * its messages as master's read queue is going away */ if (ptmp->pts_rdq) qenable(WR(ptmp->pts_rdq)); PT_EXIT_WRITE(ptmp); qprocsoff(rqp); /* Finish the close */ rqp->q_ptr = NULL; WR(rqp)->q_ptr = NULL; ptms_close(ptmp, PTMOPEN | PTLOCK); return (0); } /* * The wput procedure will only handle ioctl and flush messages. */ static void ptmwput(queue_t *qp, mblk_t *mp) { struct pt_ttys *ptmp; struct iocblk *iocp; DBG(("entering ptmwput\n")); ASSERT(qp->q_ptr); ptmp = (struct pt_ttys *)qp->q_ptr; PT_ENTER_READ(ptmp); switch (mp->b_datap->db_type) { /* * if write queue request, flush master's write * queue and send FLUSHR up slave side. If read * queue request, convert to FLUSHW and putnext(). */ case M_FLUSH: { unsigned char flush_flg = 0; DBG(("ptm got flush request\n")); if (*mp->b_rptr & FLUSHW) { DBG(("got FLUSHW, flush ptm write Q\n")); if (*mp->b_rptr & FLUSHBAND) /* * if it is a FLUSHBAND, do flushband. */ flushband(qp, *(mp->b_rptr + 1), FLUSHDATA); else flushq(qp, FLUSHDATA); flush_flg = (*mp->b_rptr & ~FLUSHW) | FLUSHR; } if (*mp->b_rptr & FLUSHR) { DBG(("got FLUSHR, set FLUSHW\n")); flush_flg |= (*mp->b_rptr & ~FLUSHR) | FLUSHW; } if (flush_flg != 0 && ptmp->pts_rdq && !(ptmp->pt_state & PTLOCK)) { DBG(("putnext to pts\n")); *mp->b_rptr = flush_flg; putnext(ptmp->pts_rdq, mp); } else freemsg(mp); break; } case M_IOCTL: iocp = (struct iocblk *)mp->b_rptr; switch (iocp->ioc_cmd) { default: if ((ptmp->pt_state & PTLOCK) || (ptmp->pts_rdq == NULL)) { DBG(("got M_IOCTL but no slave\n")); miocnak(qp, mp, 0, EINVAL); PT_EXIT_READ(ptmp); return; } (void) putq(qp, mp); break; case UNLKPT: mutex_enter(&ptmp->pt_lock); ptmp->pt_state &= ~PTLOCK; mutex_exit(&ptmp->pt_lock); /*FALLTHROUGH*/ case ISPTM: DBG(("ack the UNLKPT/ISPTM\n")); miocack(qp, mp, 0, 0); break; case ZONEPT: { zoneid_t z; int error; if ((error = drv_priv(iocp->ioc_cr)) != 0) { miocnak(qp, mp, 0, error); break; } if ((error = miocpullup(mp, sizeof (zoneid_t))) != 0) { miocnak(qp, mp, 0, error); break; } z = *((zoneid_t *)mp->b_cont->b_rptr); if (z < MIN_ZONEID || z > MAX_ZONEID) { miocnak(qp, mp, 0, EINVAL); break; } mutex_enter(&ptmp->pt_lock); ptmp->pt_zoneid = z; mutex_exit(&ptmp->pt_lock); miocack(qp, mp, 0, 0); break; } case PT_OWNER: { pt_own_t *ptop; int error; if ((error = miocpullup(mp, sizeof (pt_own_t))) != 0) { miocnak(qp, mp, 0, error); break; } ptop = (pt_own_t *)mp->b_cont->b_rptr; if (ptop->pto_ruid < 0 || ptop->pto_rgid < 0) { miocnak(qp, mp, 0, EINVAL); break; } mutex_enter(&ptmp->pt_lock); ptmp->pt_ruid = ptop->pto_ruid; ptmp->pt_rgid = ptop->pto_rgid; mutex_exit(&ptmp->pt_lock); miocack(qp, mp, 0, 0); break; } } break; case M_READ: /* Caused by ldterm - can not pass to slave */ freemsg(mp); break; /* * send other messages to slave */ default: if ((ptmp->pt_state & PTLOCK) || (ptmp->pts_rdq == NULL)) { DBG(("got msg. but no slave\n")); mp = mexchange(NULL, mp, 2, M_ERROR, -1); if (mp != NULL) { mp->b_rptr[0] = NOERROR; mp->b_rptr[1] = EINVAL; qreply(qp, mp); } PT_EXIT_READ(ptmp); return; } DBG(("put msg on master's write queue\n")); (void) putq(qp, mp); break; } DBG(("return from ptmwput()\n")); PT_EXIT_READ(ptmp); } /* * enable the write side of the slave. This triggers the * slave to send any messages queued on its write side to * the read side of this master. */ static void ptmrsrv(queue_t *qp) { struct pt_ttys *ptmp; DBG(("entering ptmrsrv\n")); ASSERT(qp->q_ptr); ptmp = (struct pt_ttys *)qp->q_ptr; PT_ENTER_READ(ptmp); if (ptmp->pts_rdq) { qenable(WR(ptmp->pts_rdq)); } PT_EXIT_READ(ptmp); DBG(("leaving ptmrsrv\n")); } /* * If there are messages on this queue that can be sent to * slave, 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 slave no matter what. */ static void ptmwsrv(queue_t *qp) { struct pt_ttys *ptmp; mblk_t *mp; DBG(("entering ptmwsrv\n")); ASSERT(qp->q_ptr); ptmp = (struct pt_ttys *)qp->q_ptr; PT_ENTER_READ(ptmp); if ((ptmp->pt_state & PTLOCK) || (ptmp->pts_rdq == NULL)) { DBG(("in master write srv proc but no slave\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 */ while ((mp = getq(qp)) != NULL) { if (mp->b_datap->db_type == M_IOCTL) miocnak(qp, mp, 0, EINVAL); else freemsg(mp); } flushq(qp, FLUSHALL); mp = mexchange(NULL, NULL, 2, M_ERROR, -1); if (mp != NULL) { mp->b_rptr[0] = NOERROR; mp->b_rptr[1] = EINVAL; qreply(qp, mp); } PT_EXIT_READ(ptmp); return; } /* * while there are messages on this write queue... */ while ((mp = getq(qp)) != NULL) { /* * if don't have control message and cannot put * msg. on slave's read queue, put it back on * this queue. */ if (mp->b_datap->db_type <= QPCTL && !bcanputnext(ptmp->pts_rdq, mp->b_band)) { DBG(("put msg. back on queue\n")); (void) putbq(qp, mp); break; } /* * else send the message up slave's stream */ DBG(("send message to slave\n")); putnext(ptmp->pts_rdq, mp); } DBG(("leaving ptmwsrv\n")); PT_EXIT_READ(ptmp); }